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44“"? LIBRARY
Michigan State
University

 

 

 

This is to certify that the

thesis entitled

Test Stand Design for a High Compression, Direct-
Injection Spark-Ignition Methanol Fueled Engine
and Results of Various Engine Configurations

presented by

Steven Robert George

has been accepted towards fulﬁllment
of the requirements for

Master oLSciencL—degree in Jiechanica]. Engineering

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Major professor

Date W

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ESE? DUE

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DECJ. 2 2002
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TEST STAND DESIGN FOR A HIGH COMPRESSION, DIRECT-
INJECTION SPARK-IGNITION METHANOL FUELED ENGINE
AND RESULTS OF VARIOUS ENGINE CONFIGURATIONS
By

Steven Robert George

A THESIS

Submitted to
Michigan State University
in partial fulfillment Of the requirements
for the degree of

MASTER OF SCIENCE
Department of Mechanical Engineering

2000

ABSTRACT

TEST STAND DESIGN FOR A HIGH COMPRESSION, DIRECT-
INJECTION SPARK-IGNITION METHANOL FUELED ENGINE
AND RESULTS OF VARIOUS ENGINE CONFIGURATIONS

By

STEVE GEORGE

A stratiﬁed charge research engine and test stand was designed and
built for this work. This engine was designed to exhibit some of the
desirable traits of both the premixed gasoline engine and modern diesel
engine. This spark ignition engine is fueled by M100 (99.99% pure
methanol), operates under high compression (19.321) and uses direct fuel
injection to form a stratiﬁcation of the fuel-air mixture in the cylinder. The
beginning of the combustion event of the stratiﬁed mixture is triggered by
spark plug discharge. Additionally, the engine head was designed to accept
a removable combustion chamber, which allows testing to determine the
effects Of combustion chamber design on engine performance. This paper
provides an explanation of the hardware included in the experimental setup
of the engine components including the fuel, cooling, intake and exhaust
systems, along with installation of instrumentation and controls for the
engine. Upon setup completion, performance results were measured from
four combustion chamber/injector conﬁgurations, and results are presented.

High speed ﬂow visualization Of different injector nozzle needle lifts
indicated that the most ideal injector fuel spray resulted with a wide spray

angle direct injector (45’) and a needle lift Of SOum. Four engine

conﬁgurations were tested examining two direct injector needle lifts, and
three combustion chamber bowl volumes while compression ratio was held
at 19.3: 1. The two injector nozzle needle lifts tested were 65pm and 50pm.
The 50pm lift injector produced better fuel atomization and resulted in a
single, continuous injection burst. The 50pm injector conﬁguration also
produced more consistent engine operation (as measured by COV in IMEP)
than did the 65pm needle lift injector, especially at part load. The
performance of the engine with three combustion chamber designs was
measured: one with a total (hemispherical) bowl volume containing 17.5%
of the total compressed volume, a second with a total (hemispherical) bowl
volume containing 32% of the total compressed volume, and a third with a
hemispherical bowl in the piston, and a non hemispherical bowl in the
head, with a bowl volume containing 35.7% of the total compressed
volume. The smaller bowl volumes produced higher IMEP and smaller
COV in IMEP than the larger chamber bowls under globally lean
conditions()t=2.0-2.75). The larger bowl volumes showed higher IMEP and
smaller COV in IMEP than did the smaller chamber bowls under globally
rich conditions (A = 1.5, 1.75).

ACKNOWLEDGMENTS

I would like to take this opportunity to thank numerous people that helped
make this work reality. First and foremost to my wife Alanna, for her
patience and help with everything I’ve done over the past several years.

My Parents, Charlie and Aggie, for the wisdom, guidance and
determination they have given me through the years. Also to the rest of my
family for their continued support, encouragement and two-wheeled stress
relief. Dr. Harold Schock, for giving me the opportunity to attend graduate
school, to be associated with the MSU Engine Research Laboratory, and for
being the Advisor for my project. Dr. Giles Brereton, for being on my
advisory committee and for helping me understand subject matter and
theory of components and ideas. Dr. Tom Shih, for being on my advisory
committee, and for taking the time to make sure I understand Fluid
Mechanics. Tom Stuecken for helping me with so many things I can’t even
remember them all, and for letting me use his shop at my convenience.
Special thanks too for his help editing my papers, helping with my target
practice, for the ever important stress relief, and for his friendship. Ed
Timm, for giving me a hand with things around the lab, and keeping Tom
and I out of too much trouble. John Brandon for helping me with electrical
troubleshooting. Bobbie and Jan for all help trying to get organized at the
lab, and for all the cookies, candies, and goodies that I really didn’t want
but ate anyway. Finally, to the rest of the lab students and staff, including
Mark Novak, Dr. Yu Liang Lin, Mahmood Rahi, Stephen Yen, Xin Zhang,
Anthony Christie, Alvin Goh, Andy Sasak, Andy Fedewa, Kyle Judd, and

Boone Keat Chui for their help on numerous occasions and matters.

iv

TABLE OF CONTENTS

LIST OF TABLES ........................................................................................ vii

LIST OF FIGURES ..................................................................................... viii
CHAPTER 1

INTRODUCTION .......................................................................................... 1

1.1 Motivation .................................................................................. 1

1.2 Introduction to Methanol as Fuel ............................................... 2

1.3 Introduction to Charge Stratiﬁcation ......................................... 4

1.4 Stratiﬁed Charge Methanol Engines .......................................... 5
CHAPTER 2

EXPERIMENTAL EQUIPMENT .................................................................. 8

2.1 Test Rig ....................................................................................... 8

2.2 Engine Head and Cam Canier .................................................. 11

2.3 Custom Service Tools ............................................................... 16

2.4 Cooling System ........................................................................ 19

2.5 Intake/Exhaust System ............................................................. 19

2.6 Fuel Supply ............................................................................... 21

2.7 Fuel Injection System ............................................................... 21

2.8 Sensors ..................................................................................... 25

2.8.1 Pressure Transducers ...................................................... 25

2. 8. 2 Thermocouples ............................................................... 26

2. 8. 3 F lowmeter ...................................................................... 26

2. 8. 4 Speed and Position Sensors ............................................ 27

2. 8. 5 Load Cell ........................................................................ 27

2. 8. 6 NF Meter ...................................................................... 28

2.9 Data Acquisition and Control Systems ..................................... 29

2.9.1 Cosworth IC5460 & 15580 ............................................. 29

2. 9. 2 SAKOR System ............................................................ 29

2. 9. 3 RTCAM System ............................................................ 30

2.10 High Speed Photography System ............................................. 31
CHAPTER 3

EXPERIMENTAL PROCEDURE ................................................................ 34

3.1 Injector Conﬁguration Selection .............................................. 34

3.1.1 Injector Nozzle Selection ............................................... 34

3.1.2 Unit Injector Driving Cam Selection ............................. 39

3.1.3 Injector Spring and Needle Lift ..................................... 39

3.2 Data Collection/Conﬁgurations ............................................... 44

3.3 Routine Maintenance ............................................................... 47

TABLE OF CONTENTS (CONT.)

CHAPTER 4

RESULTS AND DISCUSSION ................................................................... 50
4.1 Conﬁgurations l & 2 ............................................................... 50
4.2 Conﬁgurations 3 & 4 ............................................................... 52

CHAPTER 5

SUMMARY AND CONCLUSIONS ........................................................... 73

CHAPTER 6

RECOMMENDATIONS .............................................................................. 75

LIST OF REFERENCES .............................................................................. 77

vi

Table 1.

Table 2.

Table 3.

Table 4.

LIST OF TABLES

Fuel Properties ........................................................................... 3
AVL Geometric Characteristics ............................................... 10
Ford Valvetrain Component Part Numbers .............................. 12
EPA DISI Stratiﬁed Charge Methanol Engine Results ............ 55

vii

Figure 1.
Figure 2.

Figure 3.
Figure 4.
Figure 5.
Figure 6.
Figure 7.
Figure 8.
Figure 9.

Figure 10.
Figure 11.
Figure 12.
Figure 13.
Figure 14.

Figure 15.
Figure 16.
Figure 17.
Figure 18.
Figure 19.
Figure 20.
Figure 21.
Figure 22.
Figure 23.

LIST OF FIGURES

AVL Engine Block ..................................................................... 8
AVL Engine Block, Head, & Cam Carrier ................................. 9
Bearing Plate and Injector Cam ............................................... 10
AVL Engine Block and Optical Shaft Encoders ...................... 11
Cam Carrier .............................................................................. 12
Engine Head and Cam Carrier ................................................. 13
Engine Head, Insert, Spark Plug, and Injectors ....................... 13
Engine Head, Top Side ............................................................. 15
Engine Head, Bottom Side ....................................................... 16
Custom Service Tools .............................................................. 17
Overhead Engine Hoist ............................................................ 18
Coolant Pump and Valve .......................................................... 18
Exhaust Fan and Heat Exchanger ............................................ 20
Engine Head with Intake Header and Port Injector

Nozzles ..................................................................................... 20
Fuel Cell ................................................................................... 22
Direct Injector Pump and Mount ............................................. 22
Engine Head with Port Fuel Injectors ...................................... 23
Injector Setup for High Speed Filming .................................... 33
Cordin Drum Camera ............................................................... 33
Direct Injector Nozzles ............................................................ 35
Nozzle 1 Spray Pattern ............................................................ 35
Nozzle 3 Spray Pattern ............................................................ 35
Injector Needle Lift = 150nm, Weak Nozzle Spring ............... 37

viii

Figure 24.
Figure 25.
Figure 26.
Figure 27.
Figure 28.
Figure 29.
Figure 30.
Figure 31.
Figure 32.
Figure 33.
Figure 34.
Figure 35.
Figure 36.
Figure 37.
Figure 38.
Figure 39.
Figure 40.
Figure 41.
Figure 42.

Figure 43.

Figure 44.

Figure 45.

Injector Needle Lift = 150nm, Heavy Nozzle Spring .............. 37

Injector Needle Lift = 100nm, Heavy Nozzle Spring .............. 38
Injector Needle Lift = 65pm, Heavy Nozzle Spring ................ 38
Exploded View of Injector Nozzle ........................................... 41
Injector Needle Lift = 30um, Heavy Nozzle Spring ................ 43
Injector Needle Lift = 50pm, Heavy Nozzle Spring ................. 43
Compression Volume Illustration ............................................. 44
Testing Sequence ...................................................................... 46
Average IMEP, Conﬁguration 1, A = 1.5, 1.75 ........................ 59
COV of IMEP, Conﬁguration 1, l = 1.5, 1.75 .......................... 59
Average IMEP, Conﬁguration 1, A = 2.5, 2.75 .......................... 60
COV of IMEP, Conﬁguration 1, A = 2.5, 2.75 .......................... 60
Average IMEP, Conﬁguration 2, A = 1.5, 1.75 .......................... 61
COV of IMEP, Conﬁguration 2, A = 1.5, 1.75 .......................... 61
Average IMEP, Conﬁguration 3, 7» = 1.5, 1.75 .......................... 62
COV of IMEP, Conﬁguration 3, A = 1.5, 1.75 .......................... 62
Average IMEP, Conﬁguration 4, A = 1.5, 1.75 .......................... 63
COV of IMEP, Conﬁguration 4, A = 1.5, 1.75 .......................... 63
Pressure vs. Crank Angle, it = 1.5,

Conﬁguration 3 ........................................................................ 64
Pressure vs. Crank Angle, it = 1.5,

Conﬁguration 3 (cont.) ............................................................ 64
Pressure vs. Crank Angle, A = 1.75,

Conﬁguration 3 ........................................................................ 65
Pressure vs. Crank Angle, A = 1.75,

Conﬁguration 3 (cont.) ............................................................. 65

ix

Figure 46.

Figure 47.

Figure 48.

Figure 49.

Figure 50
Figure 51
Figure 52
Figure 53

Figure 54

Pressure vs. Crank Angle, Lambda = 1.5,

Conﬁguration 4 ........................................................................ 66
Pressure vs. Crank Angle, Lambda = 1.5,

Conﬁguration 4 (cont.) ........................................................... 66
Pressure vs. Crank Angle, Lambda = 1.75,

Conﬁguration 4 ....................................................................... 67
Pressure vs. Crank Angle, Lambda = 1.75,

Conﬁguration 4 (cont.) ............................................................ 67
Engine Head Detailed Drawing ............................................... 68
Cam Carrier Detailed Drawing ................................................ 69
Injector Cam Detailed Drawing ............................................... 7O
Hemispherical Bowl Combustion Chamber

Detailed Drawing ..................................................................... 71
Maximum Bowl Combustion Chamber

Detailed Drawing ..................................................................... 72

* Images in this thesis are presented in color.

CHAPTER 1

INTRODUCTION

1.1 Motivation

Over the past three decades, people have developed an increased
awareness of the depleting supply of petroleum products used today as fuel.
This awareness has raised many questions, including whether there is a
sufﬁcient supply of fossil fuels to carry mankind’s transportation needs well
into the next millennium. Although these questions have not been
deﬁnitively answered, they have sparked extensive research. Research in
this area has not only been to improve the power output and efﬁciency of
the modern internal combustion engine (typically gasoline or diesel fuel
powered), but also to develop engines that utilize alternative, renewable
power sources.

Alcohols were used as a motor fuel during the beginning of this
century, but were essentially forced off the market by abundant, low cost
gasoline. Recent focus has turned to re-exainine alcohol fuels because they
provide a renewable, clean burning alternative to gasoline. This research is
concerned with the development of an engine which functiOns by
combusting one such alcohol fuel: methanol. Properties of methanol fuel
suggest that operating an engine under high compression, direct-injection
stratiﬁed-charge (DISC) conditions may yield important efficiency gains.
The engine set up and examined in this work operates at a compression
ratio of 19.3:1, higher than conﬁgurations examined in previous works [6].

This thesis examines the preparation required to design and build a directly

injected methanol fueled engine, to set up a test cell for operating a
methanol fueled engine under these conditions, and the evaluation of the

performance of various combustion chamber designs.

1.2 Introduction to Methanol as Fuel

Alcohols have been evaluated and used as fuels for internal
combustion engines since the early 1800’s, and they have been used in the
automobile to some extent since its invention. In fact, alcohols were
frequently used as fuels for vehicles during the early part of the 20th
century, until low cost gasoline essentially forced them off the market as a
primary fuel. Alcohols are currently used as motor fuels. Alcohols,
methanol in particular, are still used today in many high performance racing
engines, where high performance is desired without great concern over cost
and fuel consumption. As time progresses, it appears that now more than
ever, methanol utilization may once again return to the automobile industry.

During the last thirty years society has developed an increased
awareness of the depletion of petroleum fuels. This awareness has
rekindled the interest in evaluating the use of synthetic fuels; and of these
fuels methanol Seems to hold the most promise. Methanol can be
manufactured from both natural gas and coal, which are believed to be in
more abundant supply than crude Oil. Also, methanol can be produced
from natural, renewable feedstocks such as municipal solid wastes and
waste biomass, in addition to speciﬁcally grown biomass, which have been
suggested as methanol feedstocks [1].

Methanol has many properties (see Table 1) that make it appealing as
a clean, renewable synthetic fuel with the potential to reduce emissions to

the environment when compared to its gasoline and diesel counterparts.

Table 1. Fuel Properties

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Characteristic Gasoline No. 2 Diesel Methanol
Speciﬁc Gravity @ 60 F 72-75 0.85 0.79
Boiling Point °F 85-437 375-630 149
Boiling Point °C 30-225 210-325 65
Heating Value (Mass)

BTU/lb 1 8,700 1 8,400 8,600
Heating Value (Mass)

MJ/kg 43.5 43 20.1
Heating Value (Bol)

BTU/Gal 1 17,000 130,000 57,000
Heating Value (Bol) MM 32 36.6 15.9
Vapor Pressure @ 100 °F

psi 9 to 13 0.04 4.6
Vapor Pressure @ 100 °F

kpa 62-90 0.27 32
Heat of Vaporization kj/kg 400 600 1,1 10
Research Octane Number 91-100 NA 112
Motor Octane Number 82-92 NA 91
Cetane Number below 15 40-60 below 15
Stoichiometric A/F 14.6 14.6 6.4

 

 

 

 

 

Researchers believe that methanol holds much promise for being the
automotive fuel of the future for many reasons, possibly the most important
ones being availability, renewability, and decreased emissions to the
environment. Methanol as a fuel is much cleaner burning than gasoline and
diesel fuel, and it is believed that the exhaust gasses (unburned fuel in
particular) are less photochemically reactive in the atmosphere [2]. These
traits are not the only ones that make methanol appealing. The methanol
fuel molecule (CH 3-0H) contains its own oxygen atom, so it requires less
air for complete combustion than gasoline. Methanol also has high octane
ratings, which are typically reported as Research Octane Number (RON) =
112, and Motor Octane Number (MON) = 91, yielding an average octane
rating of 101.5 ((RON+MON)/2). This value is signiﬁcantly higher than

the typical octane ratings for premium unleaded gasoline (92-93), allowing

a methanol fueled engine to operate with higher compression ratios than a
gasoline engine, suggesting increased thermodynamic efficiency. Methanol
has a high latent heat of vaporization, so it requires several times as much
heat to vaporize the fuel as compared to gasoline. This trait suggests
possible advantages for direct injection conﬁgurations. This high heat of
vaporization results in charge cooling, increased knock limited compression
ratio limits, and a subsequent increase in thermodynamic efﬁciency.
Finally, methanol has wide ﬂammability limits, so it will burn under lean
conditions similar to diesel fuel, suggesting the possibility of increased low
load efﬁciency. These characteristics are some of the primary reasons
methanol is seen as having potential as a fuel for stratiﬁed charge internal

combustion engines.

1.3 Introduction to Charge Stratiﬁcation

"The writer believes that there is little doubt that, sooner
or later, the system of working with a stratiﬁed charge
will become commercial, it is possible and the high
efﬁciency theoretically obtainable from it can be
approached." [3]

Sir Harry R. Ricardo, 1922

Nearly 80 years ago Sir Harry Ricardo had performed some of the
ﬁrst work with stratiﬁed charge engines, and he could clearly see the great
potential of this type of engine. The stratiﬁed charge engine is basically a
combination of the standard spark-ignition engine, and the compression-
ignition (diesel) engine, in an attempt to realize the major beneﬁts of both.
These beneﬁts are the high efﬁciency of the diesel engine, along with the
ignition control and high power output of the spark ignition (gasoline)

engine.

It is of primary importance to understand the major differences (other
than ignition type and control) between a standard gasoline cycle and a
diesel cycle to realize the beneﬁts of a stratiﬁed charge engine. In a
standard spark-ignition gasoline engine, an air fuel charge of nearly
constant composition is inducted into the cylinder during the intake stroke.
Load is varied by throttling the inducted air, decreasing the mass of fuel air
charge drawn into the cylinder. As a result, the composition of the charge
is nearly identical for every cycle, resulting in charge temperatures that are
somewhat independent of load. For the diesel cycle, load is controlled quite
differently. A diesel engine has an unthrottled air intake (with a much
higher compression ratio than a gasoline engine), so essentially the same
amount of air is drawn into the cylinder for each cycle. To control load, the
mass of fuel injected into the cylinder is changed, resulting in charge
temperatures and pressures necessary to produce the desired work per
cycle. Under low load conditions, the charge temperature after combustion
is much lower for a compression-ignition engine than for an equivalently
loaded spark ignition engine. The most important advantages of the
compression ignition engine occur at less than full load, and are a result of
the following: lower heat losses to the jacket because of lower charge
temperatures, lower losses due to dissociation and to variation in speciﬁc

heats, and reduced pumping losses because the air intake is not throttled

[4].

1.4 Stratified Charge Methanol Engines
Many of the properties of methanol suggest that it is well suited for
use in a direct injection, stratiﬁed charge (DISC) engine. Methanol, which

has wide ﬂammability limits, is better suited for more globally lean

operation than gasoline. This increases part load engine efﬁciency as in a
diesel engine [5]. Because of its higher octane rating, a D1 methanol
engine can Often operate with compression ratios in the mid-teens, verses
the typical compression ratios of about 9.0 with a current gasoline engine.
When direct fuel injection is used with methanol, the high latent heat of
vaporization cools the in-cylinder charge signiﬁcantly more than gasoline
injection. The increased charge cooling allows for an additional increase in
compression, ﬁsrther increasing thermodynamic efﬁciency [6]. Likewise,
because the heat required to vaporize the methanol lowers the mixture and
combustion temperatures, NOx emissions are generally less signiﬁcant for
methanol than for diesel engines at high loads. [7]. However, increasing
the compression ratio is still expected to increase NOx emissions (at high
loads), and attempts to decrease NOx emissions in engines usually results
in decreases in efﬁciency. [6, 8]

Recent work by Sato et.al [9] has shown that exhaust gas
recirculation (EGR) can be used to reduce the oxygen concentration in the
charge, lowering the combustion temperatures and reducing NOx emissions
in a methanol engine. This method of reducing NOx is especially useful in
a methanol-fueled engine because of its wide smokeless operating range.
Unlike diesel fueled engines, methanol combustion will not generate smoke
even if a localized poor oxygen area is present [9]. For this reason, a
methanol engine does not face the same NOx/particulate trade off that a
diesel engine faces, so EGR can be more effectively applied to reduce NOX.
Other studies have shown that supercharging can be used in conjunction
with EGR, resulting in a lowering of NOx emissions, without deteriorating
engine thermal efﬁciency, and without forming smoke in the exhaust gasses

[9]. The tendency of methanol to burn soot free, even in rich stoichiometric

conditions where oxygen deﬁciencies may exist in localized areas, also
suggests that the methanol fueled DISC engine could have greater power

potential than the modern diesel engine. [10, 11]

CHAPTER 2

EXPERIMENTAL EQUIPMENT

2.1 Test Rig

The engine used for this experimentation is an AVL model 503 single
cylinder research engine, with a custom built head and cam carrier. The
custom built head allows for direct fuel injection, and modiﬁcation of the
combustion chamber. The AVL engine block is connected to a 200hp
General Electric DC Electric dynamometer, which acts both as a power
source for motoring the engine and a brake for absorbing power produced
by the engine. The engine and DC dynamometer are connected by a
Paraﬂex ﬂexible shaft coupling, which isolates the vibrations created by the
engine from the dynamometer. This entire assembly is mounted on a large
cast iron bedplate, which is isolated from the ﬂoor via several rubber

“legs”. The dynamometer is powered by a Siemens SiemoReg DC motor

[-

 

 

. 7' ”3"“ ‘ '
Figure 2. AV]: Engine Block, Head & Cam Carrier

drive, which is controlled by and housed in an interface cabinet, built by
PowerTek, Inc.

The basis for the engine setup is the AVL model 503 engine block
(See Figure l & 2), designed speciﬁcally for research purposes. The AVL
engine is a robust, single cylinder engine block with a separate cylinder and
liner that can be shimmed to provide a range of compression ratios without
changing head designs. Mahle ﬂat-top pistons were used for all testing
conﬁgurations, and hemispherical pockets were machined into the center of
the piston face. The AVL model 503 research engine also has a large
ﬂywheel, (which has been enclosed by a shield for safety purposes), with
stamped, single degree increments for accurate timing. The AVL geometric

characteristics are as follow:

Table 2. AVL Geometric Characteristics
7.95 cm
cm

1 cm
19.321

V 1
Intake Valve 8
V 38 BBDC
V A

 

The engine has an internal cam for pushrod valve actuation and a
drive pulley out of the front (running at cam speed (crank speed/2)), which
was used for powering overhead cams. The engine case was further
modiﬁed (Figure 3), by machining a plate and bearing mount to support a
second shaft out the front of the AVL engine block (Figure 4). This shaft
also rotates at cam speed. The second shaft powers the mechanical direct
injector pump and an optical shaﬁ encoder for ﬁlming injector spray
patterns. The engine has an oil supply that can be accessed from outside the
engine, allowing external lines to connect the engine head/cam carrier to
the AVL engine oil system. An optical shaft encoder mounted on the front
of the crankshaft is used for timing the data acquisition and control

systems.

Injector

    

Figure 3. Bearing Plate and Injector Cam

10

  

Crank Shaft ’
OSE ~ . (‘3.

Figure 4. AVL Engine Block and Optical Shaft Encoders

 

2.2 Engine Head and Cam Carrier

The basic design for the engine head is Dual Over Head Cam
(DOHC) valve actuation, with four vertical valves, two intake and two
exhaust. The engine head and cam carrier were custom designed and built
for Michigan State University as separate pieces. The intent was to allow
changes in the combustion chamber geometry of the head surface without
manufacturing separate engine heads for each conﬁguration. All valve
components are supplied by Ford, and the part numbers are listed in Table
3:

11

Table 3. Ford Valvetrain Component Part Numbers

 

 

 

 

 

 

 

 

Component Part No. Component Part No.
Exhaust Valves F5 RZ-6507-D Exhaust Cam F53E-6A268-A8C
Intake Valves F5RZ—6505-D Intake Cam F 63E-6A266-AC
Rocker Arms YFlZ-6513-DA Valve Keys F5RZ-6518-B
Valve Bushings F5 RZ-65 1 0-A Valve Retainers F 5RZ-657 l -B
Valve Seal
Assembly F5RZ-6514-B Valve Adjusters F6DZ-6C501-A
Valve Springs YFlZ-6513-DA

 

 

 

 

 

Figure 5.

Cam Carrier

12

 

Magnetic
Posmon
Sensor

Port
Injector
Tube

 

Figure 7. Engine Head, Insert, Spark Plug and Injectors

l3

The cam carrier, as seen in Figures 5 & 6 and in the detailed drawing
on Figure 51, has the cams driven by adjustable pulleys out the front of the
engine. Each of these cams drives two valves via roller rocker arms and
hydraulic valve lifters. High pressure lubricating oil is supplied from the
AVL block by two lines running into the rear of the cam carrier. The
lubricating oil then drains down to the base of the head and returns to the
engine block by two additional oil lines. On the backside of the cam
carrier, a bracket has been mounted for a magnetic position sensor, which
senses the rotation of a cam-mounted magnet and outputs a pulse for every
rotation of the camshaft. This pulse is used by the engine controller to time
spark plug discharge during the correct engine cycle.

The engine head was custom designed and built to allow access for a
direct injector and a spark plug, both of which are located in a removable
block (Figures 53 & 54 ), allowing for changes in combustion chamber
pocket shape and volume. Figure 7 shows the bottom of the engine head
(with valves removed), one of the removable combustion chamber inserts,
an extended electrode spark plug, a direct injector, and a nozzle that was
installed for future port injection. Several removable chambers have been
machined with hemispherical bowls of different shapes, and one chamber
containing the maximum allowable volume, which is not hemispherical.
Additionally, the engine head was machined to accommodate a pressure
transducer for monitoring cylinder pressures. The head has also been
modiﬁed to accept a plastic stem with a small injector nozzle directed
toward the back of the intake valves (Figure 7), which can be used for port
fuel injection in future studies. The top view of the engine head (Figure 8)
shows two water passages near the openings for the removable block,
allowing coolant to ﬂow not only through the engine head, but also through

the removable portion of the combustion chamber.

14

It is also important to notice the small, quarter moon shaped
surfaces, where corners were machined to provide spark plug clearance,
decreasing the likeliness Of the spark energy shorting to the engine head
outside of the cylinder. Examining the head (with the valves removed)
from the bottom side in Figure 9, one can see the bowl with the spark plug
and direct injector inserted into the head, the port fuel injector positioned
above the valve seat, and the tapped hole for installing a pressure

transducer.

 

Figure 8. Engine Head, Top Side

15

_ Direct
Injector

Pressure

Transducer
Hole

 

 

Port Injector
Nozzle

 

 

 

Figure 9. Engine Head, Bottom Side

2.3 Custom Service Tools

Several custom tools were built to simplify routine maintenance and
inspection procedures. These tools are shown in Figure 10, unless
otherwise noted.

1. An overhead hoist was built (Figure 11) to allow one person to
disassemble the engine without the risk of damaging expensive
components. The hoist was also essential for reassembling the
engine valvetrain (installing hydraulic valve lifters and roller
rocker arms) when a second person was not available.

2. A small pipe was machined to use with a clamp to compress valve
springs in order to extract/install valve retainers.

3. A cap was made to place over the end of the cam drive pulley to
turn an optical shaft encoder for injector spray ﬁlming. An

additional bracket (not shown) was built to support the encoder.

l6

. A special wrench was made to remove the spark plug from the
combustion chamber insert. This wrench was required because of
the unique style of spark plug (Champion part #304-891/3M7)
used in combustion experimentation.

. A cylinder was machined on the ends to slide into the wrist—pin
holes in the piston. This cylinder was used to clamp the ﬂat top
pistons to a mill, so the combustion chamber pockets could be
machined into the surface of the piston.

. Special sockets were machined to tighten the high pressure direct
injector fuel line to the injector tip, and to install the cylinder
pressure transducer into the engine head.

. A vise grip was modiﬁed to compress the spring on the direct
injector nozzles. This tool was used to install shims in the direct
injector nozzle, serving one of two functions. The shims can
increase the needle spring preload, increasing the pressure at
which injection begins, or decrease the amount that the injector

needle lifts, which in general increases injection pressures, and

reduces the injected fuel droplet size.

4

   

5 6
I“
0

Figure 10. Custom Service Tools

 

l7

    

; Air Dryer 8t 5'
Regulator "

Figure 12. Coolant Pump and Valve

18

2.4 Cooling System

Engine coolant is supplied by an external system. An 110v electric
water pump supplies the pressure to pump coolant through the system
(Figure 12). A proportional control valve is located downstream of the
pump. The coolant control valve uses an electronic air pressure regulator
(controlled by the SAKOR data acquisition system, based on engine head
temperatures), to modulate the force acting on a sliding plate within the
valve. This sliding plate changes the cross sectional area of the coolant
supply line, modulating the amount of coolant ﬂowing through the engine
head and oil cooler. A mounting ﬁxture was designed and built to support
the valve, electronic pressure regulator, air line ﬁlter/dryer, and a regulator
to limit the incoming air pressure to 20 psi. The “throttled” coolant is then
directed through a turbine style ﬂowmeter and into the engine head. The
heated coolant ﬂowing out of the engine head ﬂows through an engine Oil
cooler, and is then pumped to a large, fan assisted heat exchanger located
outside the building (Figure. 13). Once the lower temperature coolant

leaves the heat exchanger, it is then returned to the coolant pump.

2.5 Intake/Exhaust System

Intake and exhaust headers were custom built to accommodate a
number of requirements, while ﬁtting neatly into allotted spaces (Figure 6).
The intake header was built to accept an easily removable roundair ﬁlter, a
port for sampling intake temperature, and threaded adapters to accept the
nozzles for port fuel injection (Figure 14). The exhaust header has similar
ports for measurement, including exhaust gas temperature, A value (A/F
sensor) and a port for future sampling of exhaust gasses for emissions
measurement. A duct is connected to the exhaust header, and noxious

gasses are drawn outside the building by an exhaust fan (Figure 13).

19

‘i ' I-‘a a. h
’ " ‘37 Mina-.‘I aw

Port Injector
Nozzles

 

Figure 14. Engine Head wih Intake Header and Prt Injector Nozzles

20

2.6 Fuel Supply

The fuel system for this engine consists of a few simple parts with
methanol safe automotive fuel hose connecting all fuel components. Fuel
storage is in a 2.5 gallon stainless steel ﬁre] cell (Figure 15), with a
methanol safe fuel pump and fuel ﬁlter located upstream of the ﬁrst
pressure regulator. A Mallory pressure regulator (with methanol safe
diaphragm), reduces fuel pressure to 60 psi, bleeding excess fuel back into
the fuel cell. The regulated fuel then ﬂows through the direct injector
pump, and returns to a second pressure regulator (for adequate back-
pressure), before returning to the fuel cell. The entire system is mounted

close to the direct injector pump to eliminate unnecessary fuel line length.

2.7 Fuel Injection Systems

This engine has been set up to operate on two separate fuel injection
systems; direct injection and port injection. Ideally, only the direct
injection will function for idle and low load conditions, whereas for future
studies the port fuel injection system will assist for higher load applications.

The direct injection consists of a GM mechanical, high-pressure
injector pump (GM unit injector pump part number 7G70, shown in Figure
16), which has been modiﬁed to supply high pressure fuel to a remote
nozzle. The unit injector pump is connected by stainless steel injector line
to a remote injector nozzle located in the removable portion of the engine
head. The GM injector is driven by a specially designed cam (protruding
from the front of the engine), which operates the unit injector plunger,
pressurizing fuel in the high pressure line. Fuel ﬂow is controlled by the
position of a small rack on the injector pump that re-orients the plunger

relative to bleeder valves within the injector.

21

‘ , Supply
/ Pressure
%' Regulator

Pressure
Regulator

Fuel
'“ “‘“ Adjustment
Rack

 

Figure 16. Direct Injector Pump and Mount

22

A direct-injector mounting ﬁxture (Figure 16) was designed for
multiple purposes. This ﬁxture connects the injector (through a sliding
plunger) to a cam follower wheel, that follows the proﬁle of a (removable)
cam mounted to the shaft protruding from the front of the AVL engine
block. The cam is mounted to the shaft by a machined key-way and secured
by two set screws, allowing easy exchange of injection cam proﬁles. The
mounting ﬁxture also provides a mechanism to adjust the injector rack
position using a standard throttle cable, and incorporates a dial gauge to
Show precise rack position of the injector. Finally, the ﬁxture is mounted to
the engine in a fashion that allows the entire unit injector to be rotated
around the driving cam. This adjustability, along with the degree

increments on the ﬁxture, allows the user to accurately vary the injection

timing of the engine.

 

. Port Injector ” -. ..
Nozzles '

Figure 17. Engine Head with Port Fuel Injectors

   
  

  

 

    

23

The injector pump creates high pressure in the fuel line, which is
connected to the nozzle located in the head. The nozzle operation is
simple: once the fuel line reaches a certain pressure, the nozzle needle lifts
off the nozzle seat and delivers fuel inside the engine cylinder. Once the
pressure in the high pressure line drops below the opening pressure, the
direct injector needle closes and the injection event has ﬁnished. Although
simple in function, there are many ways to adjust the spray pattern and
function of the nozzle, which will be discussed in Chapter 3, Experimental
Procedure.

The engine has also been set up to utilize port fuel injection for high
load applications. Because of the tight packaging of the vertical valve
system and the removable portion of the combustion chamber, there is
inadequate space to install standard port fuel injectors in the intake ports of
the engine head. With this restriction in mind, the port injector from the
GM Vortec engine line (GM part # 17091432) was utilized. It is a small
injector unit, with a long plastic tube and an injector tip pressed into the
end. This injector design allows the injector body to remain outside the
port, while the injector tube and tip are aimed in toward the valve (Figure
17). This conﬁguration allows the port fuel injector to spray onto the back
of the valves, without obstructing the intake port or signiﬁcantly reducing
airﬂow.

The GM injector functions correctly under 60 psi of fuel supply
pressure. Using the COSWORTH IC5460 engine controller, which will be
brieﬂy discussed under Data Acquisition & Control Systems, injection

timing of the port injectors can be easily controlled.

24

2.8 Sensors

Numerous sensors are used to monitor the operating characteristics of
the engine, including pressure transducers, thermocouples, ﬂow-meters,
speed and position sensors, a load cell, and a sensor for measurement of
air/fuel ratio. All of these sensors allow proper operation, and/or

characterization Of the running engine and its performance.

2.8.1 Pressure Transducers

T wo high pressure transducers (Optrand Model # Q31294-Q optical
pressure transducers) are used on the experimental setup; one in the fuel
line, and the other inside the engine cylinder. The fuel line pressure
transducer is used primarily to time the beginning of the injection event,
where the peak indicated injector line pressure is taken as the approximate
beginning of injection. It can also be used to calculate an approximate peak
fuel line pressure value (approximate because of the one sample per degree
CA resolution, which is not enough resolution to accurately describe fuel
line pressure throughout the injection event). The in-cylinder pressure
transducer is used to collect cylinder pressure vs. crank angle data, which
can be viewed and compared in raw form (Figures 42 - 49). Additionally,
the cylinder pressure can be used for calculations such as: Indicated Mean
EfTective Pressure (IMEP), Pumping Mean Effective Pressure (PMEP),
Peak Pressure Location (PPL) and Peak Pressure Value (PPV). This yields
an accurate measurement of engine performance under a given set of

conditions, such as: it, injection timing, and spark timing.

25

2.8.2 Thermocouples

K-type thermocouples are used for controlling engine operating
temperatures, and for monitoring the engine at certain operating conditions.
Components were modiﬁed to allow thermocouple access to intake and
exhaust headers, coolant inlet and outlet lines, oil lines ﬂowing to and from
the oil cooler, and in the fuel system. The removable insert from the engine
head was also modiﬁed to accept a thermocouple probe to characterize
approximate cylinder temperature. OMEGATHERM "201" High
Temperature, High Thermal Conductivity paste was sealed in the insert
with the thermocouple probe to ensure quick, accurate response of the
thermocouple. The engine head temperature reading is used to control the
amount of coolant ﬂowing through the engine, thus holding the engine
temperature within a constant range of values (186 to 194 Degrees F).
Using these temperature values, the engine can be monitored to ensure that
it is operating correctly, and to keep the engine operating temperature under

close control.

2.8.3 Flowmeter

One ﬂowmeter, located in the coolant lines, is used on the engine
stand. This meter was intended to monitor volumetric ﬂow of coolant
ﬂowing through the engine at all times. The ﬂowmeter is useful to ensure
that the coolant control valve is functioning correctly. However due to the
operation of the valve, and the response of the ﬂowmeter under unsteady
conditions, the values reported by the ﬂowmeter are insufﬁcient for
characterizing the mass ﬂow of coolant through the engine. This makes it

impossible to accurately calculate heat lost from the engine to the coolant.

26

2.8.4 Speed and Position Sensors

The speed and position sensors located in the test cell include BEI
model H25D-F3-360 Optical shaft encoders (OSE, shown in Figure 4) for
monitoring engine speed (and cam speed when injector spray ﬁlms are
taken), a cam mounted position sensor, and a dynamometer mounted speed
sensor. The OSE generates one pulse for every degree of crank angle
rotation, and an additional pulse at the pistons top dead center (TDC)
position. The OSE output provides accurate engine position and speed
information for two of the data acquisition and control systems, the
Cosworth engine controller, and the Real Time Combustion Analysis
Module (RTCAM) combustion analysis system. The Cosworth IC5460
uses the OSE once-per—degree outputs for precise control of spark and
injection timing. The RTCAM uses the OSE for accurate pressure value
sampling and pressure calculations. Additionally, when injector ﬁlms are
taken, an OSE is operated from the injector cam, ensuring proper timing of
the high-speed camera and laser. The cam position sensor provides a signal
to the IC5460 once for every complete rotation of the engine cams. This
signal is used to distinguish between the compression and exhaust strokes
of the engine, so the IC5460 will trigger a spark only during the time

speciﬁed relative to TDC compression.

2.8.5 Load Cell

A BLH Electronics model U3G1C load cell is connected to a
moment arm on the DC dynamometer. The load cell, calibrated using
known weights, measures the force exerted on it by the dynamometer
. casing. By knowing the length of the moment arm (18007"), the load cell

is used to give the torque output of the engine at a given set of conditions.

27

This torque value would then be used to calculate power output and
efﬁciency for the engine.

The load cell currently used on the test rig measures the torque
transmitted to the engine dynamometer case, which also recognizes the
effects of friction from the case bearings of the dynamometer. This effect
caused the load cell to measure values within an approximate range of i 2.5
ft-lb, while the engine was at rest. Because the estimated friction error was
such a large percentage of engine torque produced (just over 15 ft-lb at
peak output), the torque values were not accurate enough for characterizing
the performance of the engine, and were therefore used only for very rough

estimation of engine performance.

2.8.6 A/F Meter

The meter used for monitoring and recording air/fuel ratios (2.) is an
ECM AFRecorder model 2400G. Air to fuel ratios are reported as lambda
(it), the operating air/fuel ratio divided by the stoichiometric air/fuel ratio,
or the reciprocal of the equivalence ratio.

A = (A/F)/(A/F Stoichiometric)

Using a single exhaust gas sensor, the meter measures concentrations
of Oxygen (02), Carbon Monoxide (CO), and Hydrogen (H2) in the
engines exhaust. Using chemical equilibrium relations and atom balances
these readings can be used to ﬁnd the operating air/fuel ratio of the engine
for a variety of fuels, including methanol. The measurement accuracy
range of the ECM model 2400G is reported as a i 0.009 for 0.4 < A < 4.0,

with greater accuracy near stoichiometric ﬁring conditions.

28

2.9 Data Acquisition and Control Systems

Three different systems are used to acquire data and control
operation of the direct-injection, stratiﬁed charge (DISC), methanol-fueled
engine. These systems make it possible to hold tight control on the
operating parameters of the engine, and gather and store useful information
on the performance of the engine under certain conditions. Each of these
systems and their functions will be discussed brieﬂy in the following

sections.

2.9.1 Cosworth IC5460 & IC5580

The Cosworth IC5460 controls the spark timing of the engine (with
the capability to control port fuel injection for future studies). It reads
crankshaft position signals from the OSE, and uses the cam position sensor
to ensure proper cycle timing of both fuel and spark delivery. The IC5460
sends output signals to the IC 5580, a distributorless ignition system
connected to a 12v DC power supply. Using the input signal from the
IC5460 for spark timing, the IC5580 then energizes a standard 4 amp
automotive coil, and this results in a high-energy arc across the gap of the
spark plug. This ignition system only has single strike capability (only one
spark for each cycle), and does not allow the user to accurately adjust spark
current and duration. This will likely limit its utility for testing lean limit

combustion.

2.9.2 SAKOR System
The system built by SAKOR functions as a data acquisition system
'and an engine control system for the engine test cell. The system monitors

all the low speed channels, such as: thermocouple outputs, speed, torque, A

29

(from ECM), and volumetric ﬂow rates from the coolant ﬂowmeter. These
values can all be recorded and averaged over a certain time period, and the
results can be data logged in ASCII ﬁle format. Additionally, the SAKOR
system uses the thermocouple mounted in the engine head to control the
amount of coolant ﬂowing through the engine, keeping the engine cylinder
temperature within a few degrees of a screen input set-point.

The SAKOR data acquisition system also has unlimited calculation
channels for real time calculations using the input data, in addition to many
engine control functions not yet utilized in the DISC methanol engine test
stand. Some of these functions include automatic control of the
dynamometer and "throttle", allowing automatic execution of

predetermined test sequences.

2.9.3 RTCAM System

The Real Time Combustion Analysis Module collects all the high-
speed pressure vs. crank angle (P vs. CA) data from the engine. Using the
in—cylinder pressure transducer, along with the BEI optical shaft encoder
(OSE), the system can display pressure as a function of crank angle in real
time. This allows the effects of injection and ignition timing changes to be
easily Observed. The P vs. CA data (for a speciﬁed number of engine
cycles) can also be permanently recorded in ASCII ﬁle format.

Additionally, the RTCAM system can use this raw data to calculate
pressure vs. volume graphs (also available in real time), IMEP data and
PMEP data. This data can then be recorded and stored for comparison with
corresponding temperature, power, and torque data collected with the
SAKOR system. The primary function of the RTCAM system was to
record P vs. CA plots, and to calculate net IMEP values (IMEP gross —

PMEP gross), the primary method for recording engine performance.

30

2.10 High Speed Photography System

A high speed photography system was utilized to characterize direct
injector behavior (in still air), with numerous injector conﬁgurations. The
system used to ﬁlm injector behavior consists of two basic subsystems, one
is the injector/OSE system, and the other is a laser and camera system

The injector/OSE system is the physical setup for spraying the direct
injector in still air. Figure 18 shows the typical setup for viewing injector
spray patterns. The injector unit pump is driven off the cam exiting the
front of the AVL engine block. A mounting ﬁxture was fabricated to mount
an OSE to the injector cam for timing the laser and high-speed camera.

The cam driven unit injector sends pressurized fuel through the stainless
high-pressure injector line to the vertically positioned injector nozzle. An
Optrand optical pressure transducer is mounted in the high-pressure injector
line, and a thin rod supports the injector line and nozzle. Not shown in
Figure 18 are the exhaust tube for collecting the methanol fuel spray, and
the black backdrop necessary for ﬁlming of the injector spray pattern.

An Oxford copper-vapor laser was used to illuminate the fuel spray
patterns for ﬁlming, and a Cordin model 370 35mm drum camera (Figure
19) photographed the illuminated spray; Laser light from the copper vapor
laser was reduced to half strength using a beam splitter, and the useful light
was focused into a ﬁber-optic cable to transmit the laser light to the injector
setup. A ﬁxture was mounted to the engine bedplate to support the ﬁber
optic probe, and the vertical light sheet emitted from the probe was focused
on the center of the injector tip. The high-speed drum camera was then
positioned to photograph the injector tip and fuel spray perpendicular to the
“illuminated laser-light sheet. Timing of the copper vapor laser and the

high-speed camera is controlled by an Oxford Laser "N" Shot Controller,

31

and a Cordin model 447A camera controller, respectively. An automotive
timing light is used to set the beginning of the high-speed ﬁlm. Once the
engine is running at the desired speed (all injector ﬁlms were taken at 1500
RPM engine speed), the automotive timing light is used to set the camera
and laser to begin collecting images roughly 2 crank angle degrees before
the beginning Of the injection event. When all systems are timed to begin
ﬁlming just before the beginning of the injection event, the lights are turned
out. When all systems are set to collect images and the system is triggered,
the camera controller is signaled to open the shutter and the laser controller
signals the laser to pulse at 10,000 Hz. When the injector ﬁres, the pulsing
vertical laser-light sheet illuminates the center of the fuel spray, exposing
one image on each frame of the ﬁlm. When the drum in the camera has
made one complete revolution, the camera shutter is closed, and the laser
controller signals the laser to return to the full on state. The drum camera
is then unloaded, and the 35mm ﬁlm can be processed at a l-hour photo

shop for development and examination the same day.

32

 

. ‘ in . i ' .. . -, ':.
Figure 18. Injector Setup for High Speed Filming

 

Figure 19. Cordin Drum Camera

33

CHAPTER 3

EXPERIMENTAL PROCEDURE

3.1 Injector Configuration Selection

A signiﬁcant amount of time was spent examining fuel injector
nozzle spray patterns to choose the correct injector conﬁguration. Three
injector traits were considered most desirable when choosing an injector
nozzle: low penetration, large spray angle, and high atomization of the
fuel. A low penetration, large spray angle injector was desired to help
retain good stratiﬁcation of the fuel and air within the cylinder, and to
prevent the fuel spray from impinging on the surface of the piston. High
fuel atomization is desired to quickly produce an ignitable mixture near the

spark plug when the plug ﬁres.

3.1.1 Injector Nozzle Selection

Initially, there were three different injector nozzles available to use in
the DISC Methanol engine, which shall be referred to as nozzles 1, 2 and 3
(Figure 20). Nozzle 1 produced a 45° cone angle with low penetration
(Figure 21), which immediately looked promising. Nozzle 2 produced a
fuel spray very Similar to nozzle 1, with a slightly smaller spray cone angle,
and slightly more penetration. The spray produced by nozzle 3 was much
different than the previous two (Figure 22). The spray pattern from nozzle
3 produced a very narrow spray angle, and very deep penetration. The idea
of using nozzle 3 was quickly discarded, and after some discussion nozzle 1
was chosen as a result of the slightly larger spray angle it produced relative

to nozzle 2.

34

         

 

 

 

 

Q A?

Nozzle l Nozzle 2 Nozzle 3

Figure 20. Direct Injector Nozzles

 

Figure 21. Nozzle 1 Spray Pattern Figure 22. Nozzle 3 Spray Pattern

35

Once the injector nozzle was chosen for basic spray characteristics,
there were a number of undesirable traits to be corrected in the injector
spray pattern. The high speed ﬁlms for all three injectors suggested that
during a single injection event, the fuel pressure ﬂuctuations within the
high pressure fuel line were causing the injector needle to "bounce" on it’s
seat. The result of this “bouncing” was what looked to be numerous small
injection bursts within one injection event. Figures 23 through 26 all
display this bouncing effect, which is displayed most signiﬁcantly in Figure
25. Examination of Figure 25 shows that the initial injection event occurs
slightly before frame 1, but smaller injection events can be seen to begin on
frames 8, 13, 18, 22, and 26. Additionally, some Of the small injection
bursts within an injection event contained small “ripples” in the injection
spray. A speciﬁc example of this is shown in Figure 22, and in Figure 23,
between frames 25 and 28. Several different methods were explored in an
attempt to prevent needle “bouncing”, in addition to decreasing the fuel
particle size within the spray. These modiﬁcations include changing the
injector cam C-value (C-value is the maximum plunger velocity at a
rotational cam speed of 1000 RPM), changing the spring rates on the
injector nozzle, adding spacers to increase nozzle spring preload, and

adding spacers to decrease the lift of the needle in the nozzle.

36

A
7

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37

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22 23 24 25 26 27 28 29 30 31 32
n‘lII'l'IIIIH: IIIIII'I'I'IIMM Mll‘l'l‘ul‘: II”lI‘l‘I’IIM-v III‘I'I'UIIML "W‘I'I‘II'L‘I Il'hI‘I'I/IIM-s'. ill'II‘l'IIIIﬂsI IIHI'I'VIIM‘.” A'III‘I‘IIIIM-r R'III'I'I‘IIM: I

a: szl o n. w noo- I ”I JHOI - a: m 1‘00-

33 34 35 36 37 38 39 40 41 . 42 43
Figure 26. Injector Needle Lift 2 65pm, Heavy Nozzle Spring

38

3.1.2 Unit Injector Driving Cam Selection

Three different cams were machined for driving the injector pump.
The ﬁrst injector cam did not deliver the fuel required for a global in
cylinder A value of 1.5, so it was discarded. The two additional injector
cams had proﬁles resulting in different C-values. The second cam (labeled
part # 27) had a C-value of 1.5, whereas the third cam (labeled part #28)
had a C-value of 1.0. Although injector earns #27 and # 28 had the same
unit injector plunger displacement (the two cams had the same lobe height,
and therefore theoretically pumped the same amount of fuel), the faster
plunger velocity of cam # 27 appeared to pump more efﬁciently, delivering
more fuel for the same injector rack position. Cam # 28 also resulted in an
injector spray pattern that exhibited more of the “bouncing” phenomenon
than cam # 27, an effect that could have resulted from the fuel pressure
rising too slowly to the injector nozzle. An additional cam was produced
with a C-value of 2.0 in an attempt to further reduce the needle “bouncing
effect. This cam proﬁle proved too extreme, resulting in the plunger
“ﬂoating” off the back side of the cam lobe. After this series of ﬁlms, cam
# 27, with the C-value of 1.5 was chosen to carry out the rest of the

experimentation.

3.1.3 Injector Spring & Needle Lift

The ﬁrst conﬁguration for injector nozzle 1 had a very low spring
rate, with approximately 150um needle lift; its injection behavior is
illustrated in Figure 23. Frames 23 through 44 (at a frame rate of
10,000hz) are of particular interest, as they show excessive secondary
injection events, and the increased fuel droplet size resulting from them.

The ﬁrst method explored in an attempt to correct the bouncing effect, was

39

to increase the spring rate on the injector nozzle. Two springs of increased
spring rate were tested on the injector nozzle with favorable results.
However the multiple spray characteristic was still present, but to a smaller
extent. Figure 24 illustrates the behavior of the 150m lift nozzle with the
highest available spring rate installed. Frames 11 to 28 of Figure 24 show
that the “bouncing” effect of the injector nozzle needle had not been
eliminated, but slightly reduced when compared to the fuel spray with the
weaker nozzle spring. The heaviest spring resulted in a decrease in the
secondary injection duration from 2 ms to 1.6 ms (frames 23-43 in Figure
23 compared to frames 11-27 in ﬁgure 24).

The next steps taken in an attempt to eliminate the secondary
injection events and increase atomization were to sequentially reduce the
amount of needle lift during the injection event. Using standard injector
components, the needle lift was reduced from 150nm to 100nm, and the
fuel spray was once again characterized. Figure 25 shows the fuel spray
resulting from the 100nm needle lift. The reduction in needle lift from
150nm to 100nm did not yield the desired results, showing essentially no
improvement over the 150Irm lift conﬁguration. Another obstacle arose
upon discovery that there are no parts available to reduce the needle lift to
below 100nm, because the washers inserted to reduce needle lift below
100nm would make nozzle assembly impossible. To further decrease
needle lift, a special tool (Figure 10, tool #7) was made to compress the
nozzle spring, allowing extra shims (Figure 27) to be inserted between the

spring and the needle retainer after the nozzle was assembled.

4o

Needle / :1

Retainer

Custom Needle
Shims

Stock Needle
Shim

Spnng

 

Needle—
Figure 27. Exploded View Of Injector Nozzle

Using this method, shims were fabricated to decrease the needle lift
in the injector nozzle to 65pm, and another high—speed ﬁlm was taken. The
results of this ﬁlm did yield encouraging results. Although the needle
“bouncing” was not eliminated, it was reduced to the point where the
injection can be characterized by one dominant injection event (Figure 26,
frames 1-22), followed by two small bursts at the tail end of the injection
event, which begin on frames 23 and 31. This was an improvement over
the nozzle conﬁgurations with larger needle lifts (using the higher rate
spring on the injector nozzle). Both the 150nm and 100nm conﬁgurations
resulted in two distinct bursts delivering signiﬁcant amounts of fuel (the
second large injection burst for the 150IIm lift nozzle begins on frame 11 in
Figure 24, and the second large injection burst for the 100nm lift nozzle

begins on frame 8 in Figure 25), followed by a few small bursts at the tail

41

of the injection event. The performance of this injector nozzle was
encouraging. The engine was operated for data collection with the 65pm
injector for one combustion chamber bowl volume conﬁguration. Upon
observing the results, a new spacer was fabricated to further reduce needle
lift to 30pm, and more high speed images were taken.

Films taken from the 30pm lift nozzle yielded negative results. With
this needle lift, fuel line pressures climbed, surpassing 3000psi (the limit of
our pressure transducers working range) and yielding unacceptable
injection duration. The images in Figure 28 show what initially appeared to
be the beginning of the main injection event occurring on frame 5.
However, the ﬁlm clearly shows a fuel cloud from a previous burst in
Frames 1 to 4. Further studies showed that the burst beginning on Frame 5
was preceded by two other large fuel bursts, and the total injection duration
was nearly four times as long as the previous conﬁgurations. The ideal
needle lift had clearly been surpassed, so one more shim was fabricated as a
compromise between the 30pm and 65pm lift injectors.

The ﬁnal injector nozzle conﬁguration tested had a needle lift of
50pm. The 50pm injector lift conﬁguration exhibited a number of desirable
traits, including smaller fuel droplet size, and an injection event comprised
of a single, continuous spray (Figure 29). This result was not exhibited by
any of the previously tested conﬁgurations. Because the 50pm nozzle was
the only conﬁguration tested that exhibited one single injection burst, it was

used for the remaining engine performance tests.

42

_' ‘ ‘ ' , A A A
11. .. 2— .3. .4- 5 .. -....- . ...... 9. ....10. 11..

(M zuIMIImMI vwlmnﬂwu :vaII'IIIxmnI \UIMJIM-I numbed“! CHM-III.“ {.UIM-IIIIM mun-win: ‘IIIMIIIM-I "‘IIIM-IIIW Ai-IIMII

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12 135 .....l4 15 .16..

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. . t

A A A A A A A ,L i ,. ,

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I I I . I . . . J

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34 35 36 37 38 39 40 41 42 43
Figure 28. Injector Needle Lift = 30pm, Heavy Nozzle Spring

35 36 37 38 39 40 41 42 43
Figure 29. Injector Needle Lift = 50pm, Heavy Nozzle Spring

 

3.2 Data Collection/Conﬁgurations

The goal of this study was to conduct an experiment to evaluate
performance of a DISC methanol fueled engine with diﬁ‘erent combustion
chamber bowl volumes, while holding compression ratio constant. Detailed
drawings of the different engine head inserts can be found in Figures 47
and 48. Four different engine conﬁgurations have been tested, and a sketch
to illustrate the different combustion chamber volumes can be seen in

Figure 30.

 

Cylindrical
Squish

30‘“ , Volume
Volume III

Bowl
0 Volume in
Piston

 

Figure 30. Compression Volume Illustration

Conﬁguration 1. Injector needle lift = Approximately 65pm,
bowl in piston = 0.8125" hemisphere (8.75% of total comp. vol.)
bowl in head = 0.8125" hemisphere (8.75% of total comp. vol.)
Conﬁguration 2. Injector needle lift = Approximately 50pm,
bowl in piston = 0.8125" hemisphere (8.75% of total comp. vol.)
bowl in head = 0.8125" hemisphere (8.75% of total comp.vol.)
Conﬁguration 3. Injector needle liﬁ = Approximately 50pm,
bowl in piston = 1.125" hemisphere (23.25% of total comp. vol.)
bowl in head = 0.8125" hemisphere (8.75% of total comp. vol.)
Conﬁguration 4. Injector needle lift = Approximately 50pm,
bowl in piston = 1.125" hemisphere (23.25% of total comp. vol.)
bowl in head = 0.2in3 (12.45% of total comp. vol.)

For each of these engine conﬁgurations several parameters were
varied to obtain operating ranges for each conﬁguration. An example of the
test sequence for each conﬁguration would be as shown in Figure 31. For
each conﬁguration the test sequence was carried out as follows:

1. The earliest injection timing for engine operation is chosen.

2. A is chosen as 1.5.

3. The earliest spark timing for reliable engine operation is chosen

(such as 27.5° BTDC).

4. The spark timing is then retarded in steps of 25° (sometimes 5°)
increments until the timing reaches TDC, or until the engine will
no longer ﬁre reliably. At each spark timing, the engine is run
until operation stabilizes, and an IMEP value is recorded from in-
cylinder pressure.

5. Once all the data has been collected for the current value of A

45

(assuming there are some reliable operating points at the current A
value, otherwise proceed to step 6), the A value is increased by
0.25, and then return to step 3.

6. When i. values become too lean for reliable engine operation
(assuming there are reliable operating points at the current
injection timing, otherwise proceed to step 7), injection timing is
retarded by 5°, and then return to step 2.

7. Test sequence for current conﬁguration ended.

 

Earliest Spark
Timing for
Engine Operation
(ex: 275° BTDC)

 

 

 

 

 

Earliest Injection /

 

Timing for 25° BTDC
Engine Operation at / .
0 ~\

(ex: 76° BTDC) \
1:3.00

 

 

 

 

 

 

 

 

TDC

 

65° BTDC

 

Conﬁguration 1

 

 

 

Latest Injection
Timing for
Engine Operation at
1:1.50
(ex: 30° BTDC)

//|\_\

 

 

 

 

 

Conﬁguration 4

 

 

Figure 31. Testing Sequence

46

Testing methodology was to collect data from across the entire
reliable operating zone for each engine conﬁguration. Table 4 shows that
the reliable operating range was generally dependent on conﬁguration,
since the different conﬁgurations had different ranges of reliable operation.
The data collected for these tests, resulting in COV of IMEP of less than
0.12, can be found in Table 3. Injection timing is given in crank angle
degrees (CA) at the start of the injection process. At the engine speed
tested (1500 RPM), the injection period was approximately 15° CA (1.7
ms) for both injector conﬁgurations. Representative results of the tests for
all four combustion chamber conﬁgurations can be found in Figures 32
through 49, in the form of pressure vs. crank angle plots, IMEP graphs, and
COV of IMEP graphs.

3.3 Routine Maintenance

Due in large part to the extremely low lubricity and corrosive
properties of methanol, many parts of the engine required frequent
maintenance to keep the test stand in operating condition. The components
that required the most maintenance were the spark plug and the entire fuel
system, which includes the high-pressure unit injector pump and nozzle.

Because the ignition system used on the engine test stand does not
presently have spark current control, or multi-strike capability, it is very
important to keep the spark plug clean to ensure a hi gh-energy spark
between the electrodes. Because of the high compression pressures of the
test engine, there is more resistance for the ignition system to overcome to
produce a clean spark. Soot build up on the spark plug electrodes, resulting
from combustion and corrosion from the methanol/air mixture increases the

already high effective gap resistance. The increase in resistance across the

47

fouled spark plug often weakens the spark, or causes the spark plug to short
to ground outside the engine cylinder, causing misﬁres. For this reason,
engine performance often declined as the spark plug usage increased,
requiring frequent cleaning or replacing of the plug. After the spark plug
was replaced with a new (or cleaned) one, performance generally increased,
resulting in higher IMEP and lower COV in IMEP values. It is suspected
that an ignition system designed with higher current potential would
increase ignition system reliability. Also, an ignition system with multi-
strike capability would decrease the likeliness of misﬁres resulting from
inignitable fuel air mixtures near the spark plug at the time of spark.

Designing the engine head with vertical valves and a removable
portion in the combustion chamber required sacriﬁcing a bit of the user
friendliness, especially when changing the spark plug or injector nozzle. In
order to change the spark plug (or direct injector), the cam carrier must be
completely removed from the engine (this includes disconnecting the cam
position sensor and all external oil lines). Once this has been done, the
combustion chamber pocket must be removed from the engine head to
change the spark plug or injector. Often, removing the pocket results in
coolant ﬂowing into the engine cylinder, and then the head must be
removed for cleaning and inspection. Once the plug has been changed, the
insert can be re-installed in the head, and the head bolted to the cylinder.
After the engine has been pressure checked and all pressure leaks sealed,
the remainder of the engine can be re-assembled. The entire plug changing
process generally consumes a signiﬁcant amount of time.

The corrosiveness of methanol fuel had detrimental effects on the
entire fuel system. The most difﬁcult parts to service were the high-

pressure unit injector pump and the injector nozzle. Many times engine

48

performance dropped drastically over a relatively short time, resulting from
small particles getting trapped in the injector nozzle, or from corrosion on
the sealing surfaces within the injector pump or the nozzle. In most cases
when the fuel system was suspected as a primary contributor to poor engine
performance, the engine top-end (head and cam carrier) was disassembled
from the engine block, and the injector nozzle was removed. The injector
nozzle and the unit-inj ector pump were then completely disassembled, and
all sealing surfaces polished using 1pm grinding compound. Next, the
injector/OSE system (Figure 18) was setup for visualization of the injector
spray pattern in still air. When the injector once again produced an
acceptable spray pattern, the entire engine was reassembled, and

combustion testing resumed.

49

CHAPTER 4

RESULTS AND DISCUSSION

4.] Conﬁgurations l & 2

Conﬁgurations l and 2 consist of the same piston and head volumes
(each 8.75% of the total volume, for a total bowl volume of 17.5%). The
difference between these conﬁgurations is the amount of direct injector
nozzle needle lift. The needle lift for conﬁguration 1 is 65pm, whereas the
lift for conﬁguration 2 was reduced to 50pm. Conﬁgurations 1 and 2
showed similar overall trends in ﬁring conditions. In Figure 32 the early
spark timing produced lower values of IMEP at each injection timing for
the 65pm injector conﬁguration. A similar trend can be seen for the 50pm
injector in Figure 36. After the beginning of the injection event
(approximately 15° of this time period), the COV of IMEP data shown in
Figures 33 and 37 suggest that a period of 20°- 30° CA (at 1500 RPM) is
needed for more complete injection and evaporation of the fuel spray.
Conﬁgurations l and 2 display this trend, as COV values begin to settle to
acceptable levels at 20°- 30° after the beginning of the injection event. As
spark timings are advanced closer to the injection event, COV of IMEP
values increase sharply, possibly because there is insufﬁcient time for fuel
vaporization. This result can be seen in Figures 33 and 37. Using COV in
IMEP as a measure, both conﬁgurations ﬁred reliably between injection
timings of 45° and 30° BTDC, with the most promising conditions
occurring at injection of 45° BTDC. The IMEP data plots (see Figures 32
and 36) suggest that at low 7. values (A = 1.5 and 1.75), as spark timings are

50

retarded, the IMEP values increase. Peak IMEP and minimum coefﬁcient
of variations (COV) values occur near 5° BTDC spark timing. As shown in
Figure 34, similar trends are apparent at higher 9. values. However, the
IMEP values appear to peak at spark timings nearer to TDC.

The 65am injector, when used in conﬁguration 1, resulted in a few
higher overall IMEP values than when used in conﬁguration 2 (with the
50pm injector). This can be observed when comparing Figure 32 to Figure
36. The 50am conﬁguration still exhibits more stable ﬁring operations
when using COV of IMEP as a measure of stability. This is shown when
comparing Figure 33 and 37. Although IMEP values recorded for
conﬁguration 2 (Figure 36) are slightly lower than for conﬁguration 1
(Figure 32), many of the COVs of IMEP for the 50am conﬁguration
(Figure 37) are signiﬁcantly lower than the corresponding values for the
65pm conﬁguration (Figure 33). Additionally, the range of ignition timings
resulted in more consistent COV performance with the lower injector
nozzle lift. This evidence suggests that the lower lift results in more
consistent injector behavior, and the more ﬁnely atomized fuel spray
produces more stable combustion. It is suspected that the more ﬁnely
atomized the] spray leads to more rapid evaporation of the fuel droplets for
the 50pm conﬁguration. The lower evaporation times for the 50pm
conﬁguration result in COV of IMEP values that drop to lower values than
for the 65pm conﬁguration (compare Figures 33 and 37). As a result of
these ﬁndings, the 50am injector was used to carry out the next two engine

conﬁguration tests.

51

4.2 Conﬁgurations 3 & 4

Conﬁgurations 3 and 4 both utilize the 50pm injector and have
similar size bowl volumes. The head and piston bowls in conﬁgurations 3
and 4 account for 32% and 35.7% of the total compressed volume,
respectively. The larger bowl volumes of conﬁgurations 3 and 4 yielded
much different results than conﬁgurations 1 and 2, whose head and piston
bowls contain 17.5% of the total compression volume. Unlike
conﬁgurations 1 and 2, which would only ﬁre reliably with injection
timings between 45° and 30° BTDC (Refer to Table 4), pages 3 and 4 of
Table 4 show that the conﬁgurations with larger bowls only ﬁre reliably
with earlier injection timings between 70° and 45° BTDC. This trend
suggests that injection timings later than 45° BTDC do not supply an
ignitable fuel-air charge near the spark plug during ignition. It is not
clearly understood why the larger bowl conﬁgurations will not ﬁre reliably
with injection timings after 45° BTDC. Future CFD studies may provide
insight as to why this happens.

The conﬁgurations with larger bowl volumes produced noticeably
higher IMEP values and lower COV of IMEP values, at higher fuel/air
ratios (2. of 1.5 and 1.75), when compared to the smaller bowl
conﬁgurations of 1 and 2. In comparing Figures 32, 36, 38 and 40, the peak
IMEP values for the larger bowl conﬁgurations (conﬁgurations 3 and 4) are
over 90psi. Peak IMEP values for the smaller bowl conﬁgurations
(conﬁgurations 1 and 2) are below 80psi. One possible explanation for this
is that since earlier injection is possible with the larger bowl conﬁgurations
(conﬁgurations 3 and 4), there is more time available for fuel vaporization.
The increased time for vaporization results in a more consistent charge near
the spark plug during ignition, resulting in higher IMEP values and lower
COV of IMEP values.

52

Unlike conﬁgurations 1 and 2, the larger bowl conﬁgurations would
not ﬁre within an acceptable misﬁre limit (COV<0.1), at 1. values of 2 and
above. These ﬁndings suggest that with the larger bowl volumes, the
stratiﬁed charge mixture is either too lean to ignite consistently, or an
ignitable mixture is not consistently in contact with the spark plug during
the spark event.

At low 1. values, it appears that conﬁguration 3 offers the highest
performance of the four conﬁgurations tested (Figures 32-41). At a A value
of 1.5, conﬁguration 3 yields some of the highest IMEP values, and some
of the lowest COV of IMEP values of all the points tested (Figure 38).
Also, IMEP values for conﬁguration 3 appear to follow a more consistent
trend for injection and ignition event timings. The data shown in Figure 38
suggests that highest IMEP values are obtained when the ignition event lags
behind the injection event by 45° to 50° CA. Figure 38 shows that the
spark timing corresponding to the highest IMEP values are at 20°, 15°, 10°,
10°, and 5° for injection timings of 70°, 65°, 60°, 55°, and 50', before TDC.
A similar trend can be seen in Figure 40 for conﬁguration 4. It appears that
for injection timings of 70°, 65°, and 60", highest IMEP values are recorded
where the spark event lags approximately 50° behind the beginning of the
injection event. Conﬁgurations 3 and 4 (total bowl volumes of 32% and
35.7%, respectively) yield very similar results across the range of operating
conditions, with conﬁguration 3 generally resulting in higher IMEP values
and lower COV of IMEP values for corresponding operating conditions.
Since the difference in volume between conﬁgurations 3 and 4 are
relatively small, it is possible that contrast in performance may in part be
the result of the non-hemispherical bowl in the head of conﬁguration 4.
Further studies should be carried out to determine whether or not this is the

case .

53

All four conﬁgurations showed a high tendency to misﬁre once a
certain lean 1. limit was reached. Several reasons can be considered for
explaining these phenomena. Wood [13] and Balles et. al. [12] have also
observed that as engine load decreases, COV values increase sharply,
resulting in high hydrocarbon emissions. As engine load decreases, the
amount of ignitable mixture in the cylinder decreases, decreasing the odds
of the spark discharge igniting the mixture. The cycle-to-cycle variation in
ignitable charge location at the time of spark discharge also leads to low
load misﬁre. This could contribute to spark plug fouling or wetting, further
decreasing low load performance. It is possible that the lean limit observed
for the current experimentation could be increased by using an ignition
system with current boost and multi-strike capability. Ignition systems such
as this have been used in similar DISC gasoline engines , with increases in
lean limit combustion. [12, 14, 15] Throughout the experimentation the
performance decreased as the test duration increased. The performance lost
could be regained by frequent spark plug changes, and direct injector
cleaning and inspection. The recurring trend suggests that the
corrosiveness of methanol fuel [1, 8] had adverse effects on the spark plug
discharge and direct fuel injection, both of which have profound effects on

the quality of combustion [12].

54

Table 4. EPA DISI Stratiﬁed Charge Methanol Engine Results
All conﬁgurations running at 1500 RPM, Injector Cam #27 (C value = 1.5)

are color coded as follow
65 microns. Bowl in Piston = 0.8125 in

 

and
onligurntion l) Injector Poppet lift = Approx
75% of total Bowl in Head = 0.812.5 in 75% of total
onﬁguration 2) Injector Poppet lift = Approx. 50 microns. Bowl in Piston = 0.8125 in
75% of total Bowl in Head = 0.8125 in 75% of total
onﬁguration 3) Injector Poppet lift = Approx. 50 microns. Bowl in Piston =1.125 in
of total Bowl in Head = 0.8125 in 75% oftotal
,onﬁguration 4‘) Injector Poppet lift = Approx. 50 microns. Bowl in Piston =1.125
oftotal Bowl in Head = Maximum Volume of 0.2 in3 45% oftotal

   

Spark Timing T IMEP STD DEV of COV of
Lambda IMEP IMEP

0

55

Table 4. EPA DISI Stratiﬁed Charge Methanol Engine Results (cont.)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

1 30 0 1.75 9.5 70.29 2.80 0.039
1 30 2.5 2 8.9 67.23 7.17 0.104
2 45 25 1.5 7 63.39 2.22 0.033
2 45 22.5 1.5 7.5 64.92 2.43 0.036
2 45 20 1.5 7.8 67.44 2.51 0.036
2 45 17.5 1.5 8.2 68.63 2.12 0.030
2 45 15 1.5 8.6 71.22 1.92 0.026
2 45 12.5 1.5 8.5 72.15 1.74 0.023
2 45 10 1.5 8.3 72.28 1.94 0.026
2 45 7.5 1.5 8 71.72 1.95 0.026
2 45 5 1.5 7.9 72.06 1.84 0.025
2 45 2.5 1.5 7.7 72.42 2.09 0.025
2 45 20 1.75 9.1 60.10 6.21 0.099
2 45 17.5 1.75 9.1 61.99 2.08 0.032
2 45 15 1.75 8.9 62.25 2.06 0.032
2 45 12.5 1.75 8.6 61.56 2.11 0.033
2 45 10 1.75 8.2 61.64 1.77 0.028
2 45 7.5 1.75 8.1 60.59 1.61 0.026
2 45 5 1.75 7.8 59.88 2.00 0.033
2 45 2.5 1.75 7.4 58.64 2.23 0.037
2 45 15 2 7.3 55.63 5.71 0.099
2 45 12.5 2 7.1 55.74 1.83 0.032
2 45 10 2 6.9 55.88 2.01 0.035
2 45 7.5 2 6.5 55.37 2.13 0.038
2 45 5 2 6.1 53.96 2.42 0.044
2 45 2.5 2 6 52.17 2.70 0.051
2 45 12.5 2.25 5.7 51.27 5.51 0.105
2 45 10 2.25 5.4 50.74 5.88 0.114
2 45 7.5 2.25 5.3 50.37 2.89 0.056
2 45 5 2.25 4.5 47.33 3.83 0.080
2 45 2.5 2.25 4 44.37 4.01 0.089
2 45 15 2.5 3.5 43.39 3.90 0.088
2 45 12.5 2.5 3.8 " 42.40 4.65 0.108
2 45 10 2.5 3.4 41.03 4.32 0.104
2 40 10 1.5 8.4 70.31 1.82 0.025
2 40 7.5 1.5 8.3 71.10 1.81 0.025
2 40 5 1.5 8.4 73.23 1.75 0.023
2 40 2.5 1.5 8 72.65 . 1.60 0.022
2 40 10 1.75 7.8 66.68 1.75 0.025
2 40 7.5 1.75 7.6 66.00 1.77 0.026
2 40 5 1.75 7.6 67.31 1.62 0.024
2 40 2.5 1.75 7.6 67.72 1.71 0.025
2 40 5 2 6.6 63.23 1.87 0.029
2 40 2.5 2 6.4 62.27 6.42 0.102
3 70 25 1.5 10.8 83.56 2.68 0.031
3 70 20 1.5 11.3 85.54 2.69 0.030
3 70 17.5 1.5 10.6 83.20 4.28 0.050
3 70 15 1.5 10.4 83.21 4.16 0.048
3 70 10 1.5 9.4 81.35 3.14 0.038

 

56

 

Table 4. EPA DISI Stratiﬁed Charge Methanol Engine Results (cont.)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

3 70 5 1.5 8.6 76.86 5.14 0.066
3 70 25 1.75 8.8 72.61 7.55 0.099
3 70 20 1.75 9.4 75.49 3.21 0.041
3 7O 15 1.75 7 67.85 2.47 0.035
3 70 10 1.75 6.5 67.30 4.12 0.060
3 70 25 2 5.2 58.92 2.91 0.047
3 70 20 2 5.2 59.28 2.65 0.043
3 70 15 2 5.2 60.30 2.79 0.045
3 7O 10 2 4.6 58.86 6.21 0.103
3 65 20 1.5 12.7 90.46 3.50 0.037
3 65 15 1.5 13.6 96.30 3.85 0.038
3 65 10 1.5 12.7 92.01 3.41 0.036
3 65 5 1.5 10.5 83.09 8.94 0.106
3 65 20 1.75 10.1 75.35 3.17 0.040
3 65 15 1.75 9.4 74.28 3.76 0.049
3 65 10 1.75 8.6 72.57 2.71 0.036
3 65 5 1.75 7.8 68.17 6.28 0.091
3 65 20 2 7.3 63.60 7.21 0.109
3 65 15 2 7 63.24 2.95 0.045
3 65 10 2 6.9 63.37 3.23 0.050
3 60 20 1.5 12.8 83.07 3.36 0.038
3 60 15 1.5 14.2 89.43 2.94 0.032
3 60 10 1.5 13.9 91.86 2.95 0.031
3 60 5 1.5 12.6 88.16 2.58 0.029
3 60 15 1.75 9.7 74.76 3.26 0.042
3 60 10 1.75 9.3 74.98 2.69 0.035
3 60 5 1.75 8.4 70.71 3.68 0.051
3 60 10 2 7.7 65.24 3.62 0.054
3 60 5 2 6.2 59.35 7.00 0.115
3 55 20 1.5 10.1 83.71 3.99 0.045
3 55 15 1.5 11.6 90.74 3.45 0.036
3 55 10 1.5 12.3 94.44 3.29 0.034
3 55 7.5 1.75 8.4 77.25 7.81 0.099
3 55 5 1.75 8.3 75.96 2.88 0.037
3 55 2.5 1.75 7.6 73.68 3.34 0.045
3 50 10 1.5 13.5 89.53 2.70 0.029
3 50 7.5 1.5 13.8 92.43 2.63 0.028
3 50 5 1.5 14 95.61 3.39 0.035
3 50 2.5 1.5 14.4 96.66 3.76 0.031
3 50 0 1.5 13.5 94.48 4.44 0.046
3 50 7.5 1.75 11.4 80.02 7.94 0.097
3 50 5 1.75 10.6 79.21 3.60 0.044
3 50 2.5 1.75 10.4 74.86 5.47 0.085
3 45 5 1.5 13.9 92.22 3.31 0.035
4 70 12.5 1.5 12.3 86.02 9.02 0.102
4 70 15 1.5 13.5 87.17 8.85 0.098
4 70 17.5 1.5 13.7 86.54 2.63 0.029
4 70 20 1.5 13.2 84.50 3.12 0.035
4 65 12.5 1.75 9.1 65.20 3.50 0.052

 

57

 

Table 4. EPA DISI Stratiﬁed Charge Methanol Engine Results (cont.)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

4 65 15 1.75 10.2 68.35 3.88 0.055
4 65 17.5 1.75 10.7 69.39 7.33 0.102
4 65 10 1.5 13.7 84.07 3.54 0.041
4 65 12.5 1.5 14.8 87.48 2.23 0.025
4 65 15 1.5 14.3 85.23 2.21 0.025
4 65 17.5 1.5 13.7 80.38 7.99 0.095
4 65 20 1.5 13 76.84 2.63 0.033
4 65 25 1.5 13.2 74.72 8.02 0.101
4 60 12.5 1.75 10.7 71.07 2.27 0.031
4 60 15 1.75 11.1 70.65 1.94 0.027
4 60 17.5 1.75 10.8 68.22 2.23 0.031
4 60 7.5 1.5 14.9 92.88 9.16 0.096
4 60 10 1.5 14.9 95.41 2.40 0.024
4 60 15 1.5 14.1 89.05 2.96 0.032
4 55 7.5 1.5 14.8 94.62 2.67 0.028
4 55 10 1.5 15.6 96.39 2.70 0.027
4 55 15 1.5 14.6 89.26 3.08 0.033
4 50 10 1.5 12.4 89.69 2.53 0.027
4 50 12.5 1.5 12.2 84.93 2.50 0.028
4 50 15 1.5 11.3 80.69 2.90 0.034

 

58

 

       
      

 

  
    
 
       
        
   

A
70 V
O
r
so a
50 g
f
40
I
30 M
E
20 P
0 (980
2.5
Spark Timing Lambda = 1.5
(deg BTDC) 17.5 35 4o ‘ . . ' .
V30 Lambda=1.75 Wag?" Tngpg
Figure 32. Average IMEP, Conﬁguration 1, A = 1.5, 1.75
1 . .5
c 0.9
o
v :8 ﬂ
.7
g (1.6" l
0.5 E ‘ I
I 0.4 ‘ ‘ l
'2 0.3 ‘ ‘ l
P 0.2 ‘ l ‘ V _
0.1 ‘ 530
0 40 _
u; 45 Lambda - 1.75
I: 3 ,0 3o"
9' a 35
E u, 45 4° '/ lnjectionTimlng
' ' ’ BTDC)
Spark Timing '0. _ (dell
(deg BTDC) N O V\ V .Lambda- 1.5

Figure 33. COV of IMEP, Conﬁguration 1, A= 1.5, 1.75

59

   
    

A
° 7;
r f
a 50 ' l;
9
e i '2'
40 *2
I
M 30
E
P 20 f
si .
(p ) 10 l 307
a /
° . l 3": Lambda = 2.75

L I = . ' ' '
SparkTiming 2.5 ‘0 ambda 25 Injacetlgoglgrgpg
(deg BTDC) 0 V

Figure 34. Average IMEP, Conﬁguration 1, A = 2.5, 2.75

1.4
C
O 1.2
V 1
0
f 0.8 A.
I 0.6
M
E 0 4
P "c s
0.2

30,“

  

30 /
/ Injection Timing
35 / (deg BTDC)

, /,
Spark Timing 2.5 4° Lambda = 2.5
(deg BTDC) 0 V

\

Figure 35. COV of IMEP, Conﬁguration 1, A = 2.5, 2.75

60

H
I
I

m”ﬁ:‘”*€ﬁ§
A
8
3 'umz— onn~e<>

  
  

Spark Timing _ 8

(deg BTDC) ‘5 /

"I 40
a a as _ Lambda = 1.15 Injection Timing
(deg BTDC)

Figure 36. Average IMEP, Conﬁguration 2, it = 1.5, 1.75

0.0
C 0.7 ,,
o .
v 0.6 .
o 0.5
f

0.4
I ,
M 0.3
E 02
p

a. .
.': 2 ,
injection
Spark Timing 45 Timing
(deg BTDC) to V. Lambda = 1.5 (deg BTDC)

N

Figure 37. COV of IMEP, Conﬁguration 2, 7. = 1.5, 1.75

61

      
     
 
  

A
90 V
- e
as r
a
so 9
e
75
I
70 M
E
65 P
E 60
55 (08!)
15 so 6 * i
55“. Lambda = 1.5
Spark Timing '
(deg BTDC) so 55
'50 55,. g .. Lambda = 1_75 Injection Timing
. ‘ (deg BTDC)
Figure 38. Average IMEP, Conﬁguration 3, 7. = 1.5, 1.75
c 0.7
o
v 0.5
0 0.5
f
0.4
I
M 0.3
E
P 0.2 ,
0.1 57'
0 70 Lambda = 1.75
°° Injection Timing

’ 7o Lambda = 1.5 (deg BTDC)

Spark Timing '0 ‘

(deg BTDC)
Figure 39. COV of IMEP, Conﬁguration 3, it = 1.5, 1.75

62

omm~o<>

11mg—

(psi)

    

Spark Timing 8 60 . .
(deg BTDC) a 50 55 Injection Timing
v

Lambda = 1.75 (deg BTDC)

Figure 40. Average IMEP, Conﬁguration 4, A = 1.5, 1.75

c 0.9
0
v 0.0
0.7
O
f 0.6
0.5
“In 0.4
0.3 .
E 50
p 0.2
0.1

, Lambda = 1.75

Injection Timing

Lambda = 1.5 (deg BTDC)
Spark Timing ,

(deg BTDC) "’ “

Figure 41. COV of IMEP, Conﬁguration 4, 1. = 1.5, 1.75

63

1 600

1400

1 200

-1 000

Pressure (psi
0
O
O

O
O
O

400

200 "

0

340

 

1,ch

 
 
 
 
 
 
 
  

 

 

 

_
—I-—Inj = 60 BTDC, Ign = 25 BTDC

+In] = 60 BTDC, lgn = 15 BTDC
—o-—In] = 60 BTDC. Ign = 5 BTDC
In] = 55 BTDC. Ign = 20 BTDC
-—-»——Inj = 55 BTDC, Ign = 10 BTDC
Motoring

—TDC

 

 

 

 

 

360

380
Crank Angle

400

Figure 42. Pressure vs. Crank Angle, 1. = 1.5, Conﬁguration 3

 

  
 
 
 
 
   

 

 

 

 

 

 

420

 

 

 

“°° rm; —a—inj = 50 BTDC. lgn = 15 BTDC
Inj = 50 BTDC, lgn = 10 BTDC
—e—inj = 50 BTDC, lgn = 5 BTDC
1200 ﬁ—inj = 45 BTDC. lgn = 10 BTDC
Inj = 45 BTDC, lgn = 5 BTDC
Motoring
1000 —T°°
g 800
o
h
:i
a
8 600
E ,
I .
400
200
o . .
350 360 370 380 390 400
Crank Angle

Figure 43. Pressure vs. Crank Angle, I. = 1.5, Conﬁguration 3 (cont.)

64

 

 

1 200

1 000

a
O
0

Pressure (psi)
09
O
O

h
0
O

200

 

0

  
 
 
 
 
  

 

 

—X—lnj =70 BTDC, lgn = 20 BTDC

—éi-—-Inj = 70 BTDC, lgn = 15 BTDC
In] = 65 BTDC, lgn = 15 BTDC
+an = 65 BTDC, lgn = 10 BTDC
In] = 65 BTDC, lgn = 5 BTDC
Motoring

——TDC

 

 

 

 

 

 

340

350

360

370 380
Crank Angle

390 400

Figure 44. Pressure vs. Crank Angle, it = 1.75, Conﬁguration 3

 

1200

1000 *5

O
O
0

Pressure (psi)
3
8

§
0
O

200

 

0

 
 
 
 
 
 
  

 

 

E
—a—Inj = 60 BTDC, lgn = 20 BTDC

-9—In] =60 BTDC, lgn = 15 BTDC
—-—ln] = 60 BTDC, lgn = 10 BTDC
In] = 55 BTDC, lgn = 15 BTDC
—In] = 55 BTDC, lgn = 10 BTDC
—O-ln] = 50 BTDC, Ign = 10 BTDC
—t—In] = 50 BTDC. lgn = 5 BTDC
Motoring

TDC

 

 

 

 

 

340

350

360

370 380
Crank Angle

390 400 41 0

Figure 45. Pressure vs. Crank Angle, it = 1.75, Conﬁguration 3 (cont.)

65

1 600

 

Inj = 65 BTDC, lgn = 22.5 BTDC
—~'-—Inj = 65 BTDC, lgn = 17.5 BTDC
—0—Inj = 65 BTDC, lgn = 12.5 BTDC
O In] = 60 BTDC, lgn = 20 BTDC
In] = 60 BTDC, lgn = 10 BTDC

 

 
  
   
 
  
 
 
 
 
   

1 400

 

 

 

 

' Motoring
1200 ' , , —TDC
51000
e
e
5 800
3
e
a. 600

 

 

 

 

 

0
340 360 380 400
Crank Angie
Figure 46. Pressure vs. Crank Angle, 2. = 1.5, Conﬁguration 4
1600 --. , ’ ——-_—
TDC +011 = 55 BTDC. lgn = 15 BTDC

—In] = 55 BTDC, lgn = 7.5 eroc
—o—Inj = 50 BTDC, lgn = 20 BTDC

140° * —0—ln] = 50 BTDC, lgn = 10 BTDC
-o—In] = 45 BTDC, lgn = 12.5 BTDC
-ei-In] = 45 BTDC, lgn = 10 BTDC

1200 - Motoring
—roc

 

 

Pressure (psi)
O
O
O

 

 

 

340 350 360 370 380 390 400 410
Crank Angle
Figure 47. Pressure vs. Crank Angle, 7. = 1.5, Conﬁguration 4 (cont.)

66

 

 

 
 
 
 
 
   

 

 

 

 

 

 

 

 

loo 1 +in] = W
1200 , In] = 70 BTDC, lgn = 12.5 BTDC
—&—In] B 65 BTDC, lgn = 20 BTDC
—0—ln] = 65 BTDC, lgn = 15 BTDC
In] 8 65 BTDC, Ign = 12.5 BTDC
Motoring
1000 TDC
a 800
&
O
a 600
8
h
a.
400
I
200 5' 5
0
340 360 380 400
Crank Angle
Figure 48. Pressure vs. Crank Angle, 1L = 1.75, Conﬁguration 4
1400 _ _
= 60 BTDC, lgn = 12.5
=50 BTDC, lgn = 15 BTDC
1200 = 50 BTDC, lgn = 10 BTDC
——Toc
1000
5
e 000
5
s 600
a.
400
200

0
340

 

360 380

Crank Angle

400

Figure 49. Pressure vs. Crank Angle, 1. = 1.75, Conﬁguration 4 (cont.)

67

 

 

 

 

8552 TAP
(4) HOLES

1562 DR/LL
.l5 DEEP
{Z} HOLES

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REAM .l88 DEEP
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(2
IIEEE
IIE

.250 DRILL
2.10 DEEP
(2} HOLES

  

 

D/A. X .038 DEEP
SPOTFACE , (4) PLACES

         
 
 
  
   

TAP .32 DEEP
(2} HOLES

  

IIEEE IIEEE
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TAP .75 DEEP
1 HOLES
14- 0 EE

He
I!
BE

.5oooi’wPEA/y/ 500 DEEP
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.soooi’mPEAM 500 DEEP
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IEEE
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urns... 0m ar
PPEL/M RELEASE -M

II5

 

 

 

 

 

NOTCHES

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(Z) PLACES

    

SECT/ON Y-Y

 

 

    
         

   

 

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1770 D/A ('IS) TAP DP/LL THRU
M5 X 0.5 TAF' THP

SECT/ON Z -Z

 

    

 

 

FILE: spa/Elf

 

Figure 50. Engine Head Detailed Drawing

68

 

 

 

   
    
   
  
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

I l l lel II II
I m / '11 DP/LL .05 DEEP 71024
4 I “‘1 l3]:— TAP .52 DEEP ~(4JHOLE5
ﬂ ......
_ _ E l mT—TSP" Lt # | l
_ .9 3 ‘ﬁmx—em E) _
i w 1 .1 ‘5 1 — n) F 1
1024 TAP 45 DEEP 7500 _. J 7500 _ LJSE‘ I | j
(241 HOLES 0* ,_ 1.5000 _ D
y -+ .9000 .9054 14 \_ )
‘ /.4_r75 DIA. DRILL THRU
E] T "5039,1375 / /j"|" 525 x 45 CHAMFEP
THIS S1DE VENPT
- 15000 1.5 TAP FROM DPPDS/TE ,._,575 014.0,.“
500 7 7500 15 S1DE -121 HOLES 1 ,1 F
500 1DEE
_‘ r L + L _ _
C T l 7) ([7 r‘
5000 .1500 “50" \
.9000 \1250 1Wont 12 DEEP
\ 15000 ’15 j l ‘ P01? .125 D1A. DowEL 5,0909
V__r___.__7_ NH
7’ ‘ r——r——T I—vii
/ + _+ #+_ 4 \ 35554
1 ““004. 12 DEEP l j]
q 3] _ FOR 125 D1A DGWEL _ _ i05— I 20554
147750 | -— — ____] + A —- A/1552 D1ADP1LL [0625
If
53 DEEP '
45900 D H- Vw‘ ”9‘1 L7-
1. I ‘Rr
.0300 y : 1250 J 10.6001
—I— 70500 — 1250 j? —
32554 '1 -]- B 5.9374
11.0 L .1562 DIA. DP1LL + TL
L, _ _ _ _.
10.1125 ,2m0_‘ .93 DEEP _ _ f I
-— 50000 T 7.67/6
75900 I E E .5ch H’ El ) .5356
+ + + — ,
T1 2 ( l a
5.5541 / 517591
5.7341 2250’ \\#__.:::::::__ ~5000R
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5.6091 L1
15 500 .. 9009 ..
5.4111 | j '7 -’ l
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if i_i_
2250_ 5 ~\ -11DPIIL 05 DEEP 710-24 TAP
+ A .52 DEEP 141HDLES
#25259
4
5.4742
77150
E.

 

 

 

 

 
    
 
 

‘\

 

SECT/ON C-C

 

       
 
 
 
 
 
  
 
   
 

 

 

W0 125 P. 141 PLACES 125 P. l4) PLACES .m,
THIS END 7141 PLACES THIS END v14) PLACES ’96” 5’4 UNE 5055
DPPOSITE END OPPOSITE END WT" EEARWG BRIDGE 5' 1- EEF'
aEAnmn CAPS r: HOLES T1115 S1DE 1:1

 
 

1.0630“ DIA. LmE DOPE
wrrH SEAR/N6 BRIDGE D
BEARING CAPS 1NSTALLED

a TaPaL/ED - 141 LOCATIONSr

.5125 DIA .DP/LL 7.75 DEEP

TH/S END - 7.75 DEEP FROM
OPPOSITE END » DRILL 1;- TAP
ENDS

T TD 50 PS1 TEST \

.4375 Dot DRILL 100 DEEP
V4715 NPT 50TH 1/4715 NPT TAP PPDu

P .’ 51 E -121 PLACES
.3125 01A .DR/LL 7.75 DEEP 0 PDS/T 0
THIS END . 715

    
  

   
 
     

‘

12550 P. 7H1S
END - 12550 P.
OPPOSITE END

'5550 R. T1115
END 7.5550 P.
DPPGS/TE END

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

  
 
  

  

- PPELw RELEASE
II

m1
I

 

 

45374 I I /‘
ll FT— 4. UT 4
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WELD 1.
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(5554* :Ii'lgub/VAfﬂgﬂLES F T
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I .n_. A
2 15*
421 3.5

1905er SIDE

5/[6-[6 TAP .2

121 HUL
HUL E

 

 

 

-———(6.5556 (TH/5 5105 ON
0556 (OPPOSITE S/DE UNLYk—u

  

ES

SOP

10-32 TAP 35 D-
TAP DR1LL 2.375
D .- (2IHGLES

    
  

 

 

2500*“ 07A. .31 DEEP
FOR .250 001. I’d/EL
121 HOLES

.5936 P. TrP.

 

 

 

/—.SJID m 01A THRL/
r41 HOLES

 

 

 

 

 

 

 

r1400 ’7 EDNSTANT

 

 

 

 

 

 

 

 

 

 

713—143—ng

3554

 

 

 

 

 

 

 

 

 

 

 

 

 

 

(OJ/26

LYJ————’

 

L167 15 AF
.50 DEEP

- 000 1121 HOLES
410000.
«#20120—-
4—2031s—u
~—21250—-
~———3.

5/1543

2 DEEP
.257 01A DRILL mo DEEP
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TAP2

     
 

 

 

 

 

 

. 500—

 

 

 

 
 

 

 

 

DEEP
TH/S SIDE

 

 

5/15-15 TAP

22
250 DIA. DRILL [DO
111 HOLE OPPOSITE SIDE

DEEP ,
DEEP

12.35

\.4219 BIA. DRILL 112 DEEP

l/Z-(J TAP 1.02 DEEP
HOLES

   
     
 
  
     
    
    
 
 
 

 

 

 

 

 

 

 

Figure 51. Cam Carrier Detailed Drawing

69

 

 

 

 

 

N0. REVISION DATE B

PEEL/M RELEASE 2206798 1A1

 

 

 

 

 

 

 

1/4’20 TAP THE’U
“/1 WALL E (2)
HOLES 90°A/3ART

/.875O D/A.

  

1
1
1
1
L

1~/1

/.75OO

 

/_

R

" "2’88 8750

 

 

 

 

* L“ "3750 «r1.7500—»

1.0000 R. (SEE N0TE1 E 10000>

 

 

NOTE: CAM SURFACE RR0E/LE T0
BE MACH/NED ER011 CURVE
DERIVED ER011 TH/S EILE.

F/LE: 000/0527

 

 

 

Figure 52. Injector Cam Detailed Drawing

70

 

 

 

 

 

 

 

 

 
  
 
  

 
 
  
 
 
 
     
  

 

 

  
    
 
 
  

    
  

 

   
 

 

| ND.‘ REVISION I DA7E J BY
1PREL11V RELEASE 1 swealm
2.8200 .154 (”23) DRILL L
THRL/ 7 I21 HOLES
# v.01 - / II
.180 1 151 DRILL 8.00030 mm DIA. 4 300
THRU “ {4) HOLES REA/W THRU
1114 X 1.25
1.7 // 12.00 /.5 OO BOTTOM TA/D
f .7500 DIA.
A .8858 60100 .7580 A T1
- . 1110 X 1.0 TAP
THRU
564 .0359 TYP. A6875 DA
.125 R.TVP. /-5 50
1.1283 \— 1101 PLACES
1.2000 .510 R. TYP, 8750
141 PLACES
24000——»
.250 DRILL .32 DEEP
1.0800
1.0300 3125 SPHER/CAL
.4800 0525 05”“ 4800 FAD/U5
L44 DEEP
.4300
121 HOLES 4300 SECTION A—A
1 «—1.8750 TREE.)
. 1.1875 '_—71.1875
8000 7.8000
.6000
0938 DRILL .0938 DRILL
150 DEEP 1.50 DEEP
121 HOLES 121 HOLES
0353 7WD .158 DIA. DRILL
.25 DEEP 7121 PLACES .0825 DRILL
1.50 DEEP
8 75 I21 HOLES
8 23 2200 r
-0 4.072
.194 1D. X 380 '0‘" 0D. X .050 "a” II I
.125 R. TYP. DEEP O’RI/VG GROVE 421 PLACES V/EW 1N CIRCLE A
1121 PLACES SCALE.- 4.1
.0482 CONSTANT
\1
.0250 CONSTANT
.2338 R.
121 PLACES

 

 

.7038 R.
(2) PLACES

/EW OF OVAL PROJECT/ON
FILE.- 8001.520

SCALE: 2.1
Figure 53. Hemispherical Bowl Combustion Chamber Detailed Drawing

 

\/

 

 

 

7l

 

 

 

 
  
 
 
   
 
 
 
 
  
  
  
  
  
 
  
 
  
  

 

 

 

 

 

 

 

 

 

 

/.0800+
1.0300+
.4800 4. .0525 DR/LL
4500 * 1.44 DEEP
(Z) HOLES
I
| I l I
£11875 9
.8000 T ‘ T
.500 .7000
.0938 DP/LL
LEO DEEP
(Z) HOLES

.IZ5 P.TYP.
{/2} PLACES

.8 78'?”

./54 (“23) DP/LL
THPU T (2) HOLES

  

PEAM THPU

111/4 X /.25
BOTTOM TAP

 

 

TYP.

{/0} PLACES

P. TYP.
(4) PLACES

 

 

 

 

 

 

 

 

 

.250 DP/LL .32 DEEP +/.0800
111 HOLE THIS SIDE
I11 HOLE OPP. SIDE H0300
» .4800
.1875 DRILL THRO
4 .4300
. L _ I I 85.00“
I . H . J w
— A - i A i Z , /-5000 M «——1.8750 (REP)
L T T T L ,_ LILII — 71.1875
PPPPPPP ﬁ ’ 'TL8000
‘ ' .6000

 

 

.0938 DRILL
A 1.50 DEEP
12) HOLES
0353 TYP- .158 DIA. DRILL
/ .25 DEEP A (2) PLACES .0825 DRILL
1.50 DEEP
1
g5 .2200 a 75 2) HOLES
_. I.4387
to »002 i.
.194 ID. X 380 w 0.0. X .050 0"” «PI/I480 11 u
DEEP OAR/N0 GROVE 7(2) PLACES VIEW IN CIRCLE A

 

SCALE: 4:/
.0462 CONSTANT

.0250 CONSTANT

.2338 P.
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72

Figure 54. Maximum Bowl Combustion Chamber Detailed Drawing

 

CHAPTER 5

SUMMARY AND CONCLUSIONS

A test stand has been completely assembled for operating a DISC
Methanol engine. The engine has been instrumented to monitor in-cylinder
pressure and the pressure within the fuel line between the injector nozzle
and the unit pump. Other instrumentation has been installed to monitor air
fuel ratio, to provide tight control of engine operating temperatures, and to
monitor other operating temperatures including intake and exhaust gasses,
coolant, and oil. Flow visualization was utilized to select an appropriate
direct injector nozzle, and to select a needle lift for that nozzle which
resulted in an acceptable injector spray pattern. Three combustion chamber
geometries were designed, fabricated, and experimentally evaluated.
Geometry details of these combustion chambers are shown in Appendix A,
and the performance results of the different bowl conﬁgurations are given
in Figures 32-49. Timing variability and conﬁguration for each injector
were studied with some injection points working well and others
performing poorly. Initial results suggest the following:

0 The 50pm injector conﬁguration produced a single injection event
and a more ﬁnely atomized fuel spray than the 65pm injector. The
65pm injector consistently produced multiple bursts in a single
injection. The 50pm injector produced consistent engine operation
as measured by COV in IMEP.

0 The 30um injector also consistently produced multiple bursts in a

73

single injection event. Because of the lower ﬂow rate of fuel
through the injector nozzle resulting from the lower needle liﬁ,
injection pressures rose beyond the measuring capability of our
instrumentation. The injection times for the 30um injector also
increased, resulting in injection durations too long for proper fuel
delivery.

The larger bowl volumes showed higher IMEP and smaller COV
in IMEP than did the smaller chamber bowls under (relative)
globally rich conditions (A = 1.5, 1.75).

The smaller bowl volumes showed higher IMEP and smaller COV
in IMEP than did the larger chamber bowls under globally lean
conditions (A = 2.0 - 2.75).

The smaller bowl volumes ﬁred consistently only at late injection
timings (45°- 30° BTDC), whereas the larger bowl volumes ﬁred
consistently only at earlier injection timings (70°- 45' BTDC) for
all A values.

Hemispherical bowls in the engine head and piston showed higher
IMEP and Smaller COV in IMEP than did the non-hemispherical

bowls of similar volume.

These results suggest that there may be beneﬁts to a “hybrid”

conﬁguration to exhibit the best combination of the examined

conﬁgurations. This conﬁguration would utilize the 50pm injector and

hemispherical bowls in the piston and cylinder. This setup is expected to

exhibit the tendencies of both the smaller bowl at lean conditions, and the

larger bowl at more rich ﬁring conditions.

74

CHAPTER 6

RECOMMENDATIONS

1. An ignition system should be purchased from Nexum
Instrumentation, which allows direct control of ignition parameters.
The actively controlled ignition parameters are spark current, spark
duration, and multi-strike capability.

2. An in line torque sensor should be purchased and installed
between the engine and dynamometer for accurate torque

measurements.

3. A new combustion analysis system should be purchased to
increase in—cylinder and fuel line measurement resolution.
Additionally, this system should allow simultaneous measurement
and data-logging of raw pressure vs. crank angle data along with
calculated channels such as IMEP, PMEP, PPL, and PPV.

4. A “hybrid” piston bowl conﬁguration should be tested to explore a
combination of the previously examined conﬁgurations. This
conﬁguration would utilize the 50mm injector and a small
hemispherical bowl in the piston, with a larger bowl machined
outside this inner bowl. This bowl conﬁguration may exhibit some
of the tendencies of both the smaller bowl at lean conditions, and
the larger bowl at more rich ﬁring conditions.

, 5. Then engine should be connected to an emissions bench, allowing

simultaneous performance and emissions measurements.

75

LIST OF REFERENCES

10.

LIST OF REFERENCES

Wagner, T. 0., Gray, D. S., Zarah, B. Y., and Kozinski, A. A.,
“Practicality of Alcohols as Motor F uel,” SAE Paper 790429,
1979

“Analysis of the Economic and Environmental Effects of
Methanolas an Automotive F uel,” US. Environmental
Protection Agency, Ofﬁce of Mobile Sources, September, 1989

Ricardo, Sir Harry R., “Recent Research Work on the Internal
Combustion Engine,” 1922. Transactions of The Society of
Automotive Engineers Inc. Part 1 Volume XVII, 30, 1923

Conta, L. D. and Durbetaki, P., “A Method of Charge
Stratiﬁcation for a Four-Stroke-Cycle Spark-Ignition Engine,”
SAE Paper 580127, 1958

Black, E, “An Overview of the Technical Implications of
Methanol and Ethanol as Highway Motor Vehicle Fuels,” SAE
Paper 912413, 1991

Brinkman, N. D., “Effect of Compression Ratio on Exhaust
Emissions and Performance of a Methanol-Fueled Single-
Cylinder Engine,” SAE paper 770791, 1977

Hilger, U., Jain, G., Scheid, E., Pischinger, F., Gruetsch, R.,
Bernhardt, W., Heinrich, H., Weidmann, K., and Rogers, G.,
“Development of a Direct Injected Neat Methanol Engine For
Passenger Car Applications,” SAE Paper 901521, 1991

Hagen, D. L., “Methanol as 3 Fuel: A Review with
Bibliography,” SAE Paper 770792, 1977

Sato, Y., Noda, A., and Sakamoto, T., “Combustion and NOx
Emission Characteristics in a D1 Methanol Engine Using
Supercharging with EGR,” SAE Paper 971647, 1997.

Dhinagar, S. J., Nagalingam, B., and Gopalakrishnan, K. V.,
“Experimental Investigations on Three Different Methods of
Using 100% Methanol in a Low Heat Rejection Engine,” SAE
Paper 920197, 1997

77

11.

12.

13.

14.

15.

16.

17.

18.

19.

20.

LIST OF REFERENCES (CONT.)

Dhinagar, S. J ., Nagalingam, B., and Gopalakrishnan, K. V.,
“Spark-Assisted Alcohol Operation in a Low Heat Rejection
Engine,” SAE Paper 950059, 1995

Balles, E. N., Ekchian, J. A. and Heywood, J. B., “Fuel
Injection Characteristics and Combustion Behavior of a Direct-
Injection Stratiﬁed-Charge Engine,“ SAE Paper 841379, 1984

Wood, C. D., “Unthrottled Open-Chamber Stratiﬁed Charge
Engines,” SAE Paper 780341, 1978

Frank, R. M. and Heywood, J. B., “Combustion
Characterization in a Direct-Injection Stratiﬁed-Charge Engine
and Implications on Hydrocarbon Emissions,” SAE Paper
892058, 1989

Frank, R. M. and Heywood, J. B., “The Importance of
Injection System Characteristics on Hydrocarbon Emissions
from a Direct-Injection Stratiﬁed-Charge Engine,” SAE Paper
900609, 1990

Sato, Y., Noda, A., and Sakamoto, T., “Effect of EGR on NOx
and Thermal Efﬁciency Improvement in a DJ. Methanol
Engine for Light Duty Vehicles,” SAE Paper 930758, 1993.

Tsuchiya, K., Seko, T., “Combustion Improvement of Heavy-
Duty Methanol Engine by Using Autoignition System,” SAE
Paper 950060, 1995

Kusake, J ., Daisho, Y., Saito, T. and Kihara, R., “Controlling
Combustion Characteristics Using a Slit Nozzle in a Direct-
Injection Methanol Engine,” SAE Paper 941909, 1994

Conta, L. D. and Durbetaki, P., Bascunana, J. L., “Stratiﬁed
Charge Operation of Spark Ignition Engines,” SAE Paper
610269, 1961

Haslett, R. A., Monaghan, M. L. and McFadden, J. J.,
“Stratiﬁed Charge Engines,” SAE Paper 760755, 1976

78

21.

22.

23.

LIST OF REFERENCES (CONT.)

Anderson, R. W., Yang, J., Brehob, D. D., Vallance, J. K. and
Whiteaker, R. M., “Understanding the Thermodynamics of
Direct Injection Spark Ignition (DISI) Combustion Systems:

An Analytical and Experimental Investigation,” SAE Paper
962018, 1996

Alger, T., Hall, M. and Matthews, R., “Fuel Spray Dyanamics
and Fuel Vapor Concentration Near the Spark Plug in a Direct-
Injected 4-Valve SI Engine,” SAE Paper 1998-01-0497, 1998

Heywood, J .B., “Internal Combustion Engine Fundamentals,
McGraw-Hill, New York, 1988

79

 

 

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