...... SPEED CONTROL AND REVERSING MECHANISM OF HEAVY DUTY. DIESEL ENGINES ThesisfuthobogmofM.S. MICHIGAN STATE COLLEGE Chi-chu Kuo I949 THESIS . I 'I I ‘ This is to certifg that the thesis entitled . ; Speed Control and Reversing : Mechanism of Heavy Duty Diesel Engines presented In] Chi-chu Kuo has been accepted towards fulfillment . , ml the requirements for M85ter5 degree in £th ELEP- ‘ W ' i Maiul‘ [IruleSsnr .- can-a! l Date MM SPEED CONTROL AND WING MARIE}! OF HEAVY DUTY DIBEL manta By Chi-aha Inc J A WIS Submitted to the School of Graduate Studies of Michigan Stats 00110;. of Apiculturo and Applied Science in putt-.1 fulfillment of the ”wire-lull:- for the degree of NIH W SCIENCE Department: of Mechanical Engineering 1949 THESIS ACKNOWLEDGMENT The author is deeply indebted to Professor G. W. Hobbs, fcr h1- guidence end fa' hie valuable advice which nude an. work‘poe- eible. TABLE CF CONTENTS Page 8P0“ Control Of D1080]. ”maeeeeeeeeeeeeeeeeeeeeee 1 Definition of a Diesel Engine Governor and the thin TYPOU UBdeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee 1 H Th0 Regulating Governor”.......................... N The Overspeed Governor............................. The Overepeed Trip................................. Development of the Regulating Governor............. She Speed Measuring‘Meohanisnh..................... Th. mnciplu IWOIVOd eeeeeeeeeeeeeeeeeeeeeeeeeee OIIFDCDN The Fuel Changing Mechanism........................ Combined Action of the Speed Measuring Mechanism ‘nd the m0]. Ming “annalmeeeeeeeeeeeeeeeeeeee 0! Simple Mechanical Adjustable Speed Droop Governor” 8 Simple Hydraulic Speed Droop Governor.............. 11 Oil Hessure Supply Source......................... 13 Simple Hydraulic Speed Droop Governor.............. l4 Isoohronous (Constant Speed) Hydraulic Governor.... 15 Speed Adjustnait................................... 23 Mechanical Load Lidting........................... 24 Hydraulic Load Hmiting............................ 24 Types of Pilot Valves and Power Pistons............ 25 (Continued) n {5“ J . Page The Double.Acting Pilot V‘IVOeeeeeeeeeeeeeeeeeeeeeee 25 Th. 813510.A0t1n8 Pilot V‘lvaeeeeeeeeeeeeeeeeeeeeeee 25 Th0 Differential Pilot valve........................ 25 Other AuxiliCry Devices............................. 26 RUVUrO1n8 MbOh‘ni'm.Of D1...1 EnginCOeeeeeeeeeeeeeeeee 27 DCtC110d Descripbian for AhC‘d Bthtingeeeeeeeeeeeee 3‘ Detailed Description of Reversing Gear Ahead to utom...‘00.0.0000...OOOOOOOOOOOOOOOOOOO0.000...... 35 ilitfitttttittlt ttttttttttfitt tttttttfittt *tttttttt ##ttttt *tt‘t tit # (1) 3mm CONTROL at? mesa. ENGINES SPEED CONTROL CF DIEKL NGINB It is the purpose of this thesis to provide the basis for'an understanding of the fundamentals of diesel engine control. A com-‘ plete knowledge of all of the principles involved in speed control is essential in the design of governors. A simplified knowledge of the elementary principles is neces- sary for an intelligent study of'the operation of governors and the application of a governor to the engine. Therefore, the ele- nentary principles [resented in this tissue are greatly simplified. avoiding any reference to mechanical and ludrsulic formulae. No couplets technical treatment of the subject is available, but readers desiring advanced theory and design of speed measuring neohanisn my consult mechanical handbooks or "Governors and the Governing of Prime Movers“ by W. Trinks. DEFINITION OF A DIRK. ENGINE GOVERNOR AND THE MAIN TYPE USED: A diesel engine speed governor is a speed sensitive device used to control or limit the speed of the engine. There are three min types of diesel engine governors. They are: l. The regulating governor. z. The overepeed governor. S. The overspeed trip. hon of these types control the ugine speed but in a different nay. THE WING GOVERNOR: The regulating governor is used to naintain the engine at normal operating speed by continuous regulation -1- HIGH SPEED a Not MAL OPERA r/~&_ SPEED a; 5mm: Low Span ‘ Reammme GOVERNOR MIN TAM/5 7/05 SPEED TIME FIG. 1 Dame/~61 OVER5PEED SAFE Hm SPEED "I EQUIPMENT Home Ovens/’55 D Go yams $57 To mars OVER AT ms 5PEED q Ova/2.517550 Gave/2m Met/Ive Sen HIM SPEFD Omsk CaNTRaL 7 TO fiatfmn AT THIS Porn/T NORMAL OPERAme; \ 3pm: 0F Ewe/ms Low SPEED 4 N0 SPEED d Ovmpssv Gown/van OVERSFEED Gemnyak T Nor ACTING’ ‘ IN ACTION 1 5 TAR 7' TIME FIG. 2 DAMACrINCv OVERSPEED SAFE HIGH SPEED A AbIzMAL OPERA TING- _ SPEEPOF five/Ive — Low 5PEED N0 SPEED OWER CONTROL. EQUIPMENT FAILS To FUNC 770M AT 77/15 POINT OVERSPEED TRIP ACTS AT rII/s 5P£ED ro REDUCE even/E 5/5519 [Iver/Ive s TOPPED ‘n' OVERSPEED TRIP 0w: RSPEED 7km IN AC TION NOT ACTlNfi' .SI'ART TIME FIG. 3 e 6i WSQK :35, oz: ow. no? 295x 3 I t 62:? 82 3.1K. QwNRnkin I QER neonatap Shh emwdwumiQ l D mmdm, OZ I waumz 2.04 mzlokw no Qmwaw I eat 3%.th 4.3%: ”I 5250‘ gt a w 5: 33 on I Q >33 Wu 32¢ nzmSQSow mum m. t «m, QW>QSWQ QWWKWYWSQ :VQMKZQU ”Nth to mustU .l .258 net at oxiwok E 95%me RSR mandwkmsQ Qmmhmkmxg mzwfimk Qmmkm, LISA men bx I hitting 3 ca den Qmwam «was of the fuel supply. It usually eleninates the necessity of an operator at the fuel control throttle. See Fig. 1. THE OVERSPBD GOVERNOR: The overspeed governor is used to prevent the engine from overspeeding and functions as a safety de- vice only. It does not act to control speed unless other equip-eat has failed to do so. It allows the engine to continue running at a higher speed than ncrnal engine speed. but below a speed when dam- age to the engine night result. See Fig. 2. THE OVERSPEED TRIP: The overspeed trip is used to prevent the engine from overspeeding, and function as a safety device only. It differs from the overspeed governor in that it reaoes the speed of, or steps the engine. There are two types of overspeed trips used. The first and nest cannonly used type is the one that cuts off the fuel supply or blocks off the air supply to shut down the engine in case of over- speed. See Fig. 3. It is necessary for the engine operator to re- set the trip nmally before the engine can be restarted. The second type of overspeed trip is the Autonntic reset type. In case of overspeed it will out off the fuel supply or block off the air supply until the engine is reduced to a pro-selected speed. Then it will automatically reset, allowing the engine to return to nor- mal speed. If the cause of the overspeed has not been removed, the trip will again go through its cycle of operation and continue to do so until the engine operator remedies the cause of overspeed. See Fig. 4 for example of operation where the cause of the overspeed does m 6Q m2 \ g. . .5. E m 295m 2\ I ethos scar zoio.‘ 2‘, Show .8: 5E ommawauam its.“ Sudanese dis antennae neck SmamamaO / L251 mix 5.. {Gigi 0k with #2521:va qOEZcU mmtko L. .5 OR betel 9...: at namwmk met bx 93me man Qmmamamao ask meamxmxo nwmdm. eat at Qmmam, mi» .3 WkUex QER QNNQWKNng Wk UT KER QNNQMSVSQ I Qumdm, 02 I meAW >304 mgezw .3 waam, Itzt .QMQQ ntSdoz I Qmmdm nt$ mkqm, Qmmamkmib fit .eEtSaVQ not exist after the trip resets. See Fig. 5 for example of opera- tion where the cause of the overspeed continues to exist after each resetting of the trip. Attention from the engine operator is re- quired before normal engine operation my be resumed. RMOPMENT OF THE REMATING GWOR: The following discus- sion'traces the develppment of the regulating governor beginning ith the principles of a simple speed measuring device, through a series of logical changes, to the deraulic compensating isochrcn- one (constant speed) governor. The speed of a diesel engine may be roughly controlled by watching a tachometer which indicates engine speed, and making fuel changes annually to correct for changes in speed. If the engine speeds up, reduce fuel. If the engine slows down, increase fuel. Speed control any be obtained by this method, but the accuracy of control is dependent on the skill of the person reading the tachom- eter and taking the fuel corrections. A regulating governor controls speed by the same process, elim- inating the person required to watch the tachometer and to mice fuel changes. 1. It measures changes in engine speed. 2. It adjusts the fuel supply to correct for the change in speed. As a result, the engine speed tends to re- main constant. . Eran the above. it is obvious that there are two essential parts to every regulating governor. .3- m .99.“ QQ.»\ fixQWx \Q Mi? VOW. \VVVUKW . mtxxntmv kno§xoh .IIII/ . 03th vok Exs§tm fi\ \1 3.33 3...an f / / _ q V\N~\-1VII*_W7W// . ///H .n L «$.st \ox. 903$ ? Ml \Vub Ek0§dm hrfim “Ska «1...! 9a 0.5le to‘oukm. l. The speed measuring mechanism. 2. The fuel changing nechanism. ' . THE SPEED MEASURING WM: Experience has ”proven the ad- 'vantages of a revolving weight flyball (or flyweight) speed measur- ing mechanism. A typical one is shown in Fig. 6. 1. It is simple. 2. It has few moving parts. 3. It measures speed very accurately. 1:1}. rummage 11119va ARE A3 roams: Fig. 6. l. The flyweights, on the ends of ”LP shaped ballarn, are rotated by the engine. 2. The weights exert centrifugal force alt-1rd this to the rotation. The force depends on the speed of rotation. 3. ‘L‘speeder spring opposes the centrifugal force of the Imights, thus tending to hold then.in.hy acting against the toe end of the ballarn. The force exerted by the spring is dependent on its adjustable compressed length. This spring Inst be designed to satch the characteristic of the weights. 4. The weights'will remain in one position if the spring force is sufficient tc‘balance the centrifugal force. 6. If the engine speeds up, centrifugal force increases and the weights will move out, raising the ballarm toes, and increasing the spring force until a balance of forces exists. .4- x. . 3K \SENQQ rock Vma...‘ ll? 4.. ll! on \nck ghetto a .4 «SQQ‘ aoum Mafia“ ‘05..“ on}: Vcttob Est 3 $835 \ non cock» 0 Lo 9 fiuhuvxtmqlwl.\ finch. UR aQINC £95» All: Vomx Lwcoxmn «when 5.: woken. L view 43$: @U‘ l 6. If the engine slows down. the weights more in. lower the ballarn toes. and reduce the spring force until a balance of forces exists. m FUEL memo MECHANISM: The fuel changing nechanisn of a diesel engine consists of a mechanical or hydraulic force, con- trolled by the speed neasuring mechanism, acting through linkage to change the fuel setting. The fuel changing mechanism of a diesel engine. see Fig. 7, includes tn, following parts: 1. Power Device: This is represented by the speeder rod transnitting power directly frua the flyweights. 2. Linkage: Connects the power device and the fuel control valve. I 3. The Fuel Control Valve: Fuel insection pumps are used on diesel engines, but for the sake of simplicity a very sinple valve is shown in the cuts to mks the mel open- ing plainly visible. COMBINED ACTION or THE SPEED MEASURING WM AND THE FUE- CEANGING MECHANISM: (31m mm. FIXED SPEED DROOP GOVERNOR.) Load Increase: f 1. Load is applied to the engine and its speed decreases. See Fig. 7. 2. Decreased engine speed results in decreased ballam speed. 3. Decreased ballarn speed results in reduced centrifugal -5- 4. 5. force of the weights, allowing the speeder spring to force the flyweights in kind love the speeder rod down. As the speeder rod moves down. the fuel valve opens to increase fuel. The fuel increase supplies additioml power to the engine to carry the increased load. hgine speed picks up, but does not reach crigiml speed because it 1: ”tunic-I11}: impo- sible to keep the throttle open for load and at the same tine bring the weights back to the original position. There met be a greater fuel opening for the increased load. This can only be accomplished by the ballar. being in from! the vertical by virtue of slower speed. Load Decrease: 1. 4. Load is reduced and the engine speed increases. See Fig. 7. Increased engine speed results in increased ballarn speed. Higher ballarn speed results in. increased centrifugal force acting against the speeder spring to raise the speeder rod. As the speeder rod moves up, the fuel valve closes to reduce fuel. The reduction in fuel reduces the engine output to nest the reduced lead. -6- NORMAL OPERA TING“ SPEED OF E NG-INE Lon/5R SPEED _ N0 LOAD FULL L049 t howl g. FIG. 8 6. The engine speed drops, but not to the former load speed because it is nechanically impossible to unin- tain reduced throttle with weights back in original position. a smaller fuel opening is necessary for the reduced load, consequently the bananas are out from vertical. indicating a slightly higher speed than before. The characteristic of a decrease in engine speed as load is picked up and an increase of speed as load is dropped off is called speed droop. See. Fig. 8. Speed droop is nechanically inherent in this sinple governor, and 1: present in sufficient quantity, has the effect of stabilising the movement of the fuel control valve. Lack of droop, or insufficient droop, will allow the fuel valve to open . and close too far, resulting in overcorrection of the fuel, or what is ocnonly known as hunting or surging. The advantages of this type of governor are: 1. It is inexpensive. 2. It is satisfactory where it is not necessary to main- tain the same speed, regardless of load. 8. It is extremely simple and has few parts. The disadvantages are: 5 1. It is not powerful enough for snny’ prime movers. 2. It my not be stable for all siseiload changes, and the means used to nice it stable also cause sluggishness. 3. It has no adjustable speed droop. -7- Bar/1 E~&/~E s RUN/VIM? DROOP 0F A r 7/115 SPEED BEFORE [News “8 ,7" LOAD l5 AWL IED Dkoop 0F ENé/NE ‘2: " F1111. [DAD 1. 0A D =11 FIG. 9 4. It is not isochroncus (will not maintain engine at one speed regardless of load). If the governor is to be used for parallel operation of two or more engines driving the same shaft or in the same A. C. electri- cal system. it is sometime desirable to be able to run one engine iscchronously to maintain the shaft speed or nintain 60 cycle fr’e-k quenoy. A simple speed droop governor cannot be adjusted to do this. 31m: mmxm mamas: arm moor common. Speed droop adjustment pn‘mits changing the stabilising action of the governor. .This is accomplished by altering the speeder spring force or compres- sion for each particular fuel ”setting. The greater a change of spring force there is for a given fuel change the greater will be the stabi- lising action. If the engine is running alone. increased droop will result in decreased engine speed as load is picked up, and the number of false corrective movements of the fuel mechanism will be reduced. If the engine is paralleled with other engines, increased droop will result in it, assuming a snnller percentage of the lad change. The reason for this is that as an engine with speed droop is reduced toward sero the engine becomes able to change load without changing speed. Fig. 9: Assume for purpose of exploration that two equal sise engines ”A“ and 'B" are paralleled and are running at ml speed without load. 'The two sloping lines represent the amount of droop on each. hgine "B‘ is set for twice the anoint cf droop set on Chain. "A” e ON 6Q Q .34 _ QWQV 3am n m nah sad QM to 2st gawk Emma” «9:04 a Edam. aside: ammuowmv mu 93.x cm: at omega, met .3 rum. is. anthem atom 2 6E r .4 9x3 hank QMQQowm< we Edd NNk to. Qmma W math .5. >3! 4.5: mmzaozw 1.8m Amman in» 96 lo 20: UDQMR Qmmam «when 3de 3:82 S. .er 1* Q VQN no.3 43¢ 33 on « \ \x\ \\\\\\\\\y \ \ \\ A \ \ \ \ W “36.: x x \ x \ \ \ \ \ \\ \ \ \ \x \ \ \ \ \ \ \ \ \ \ \ \ \samv. \ \ \K x \x \ \\ \nucx04\ \\ \ \ \ \ N \ \\L\ L\\ QMNQOWQ‘ ms neéfl MNLKW Qmmkm: “SR Lt 29M «or: mmzagm Ikom Amman SE 9.0 up >8: gawk Qmmam. union omnum, 4502 m\acm\ amen % é M n \ cw: QTQq \\ . \ sum... \ ng 2mg” ,wxlmlcmqs no {elegant a be \\\ \\ \ \ \\ \\ x x mm ,Qmwam «when n [all munch 438$ The engines will divide an amount of load inversely paper- tional to the amount of droop on each. For this reason engine "a‘ will assume twice the amount of load that willrbe assumed by engine ”B“. Fig. 10. 1:1. load equal e. three-eights of the capacity of one engine is applied to the system, the engines will divide an amount of lead inversely proportional to the amount of droop on the engines, or engine "A" will assume twice the load of engine ”B". Note that both engines met be running at the same speed because they are interccmected. Fig. 11: If a load equal to three-fourths of the capacity of one engine is applied to the system, engine “A" will be carrying one-half load and '3- one-fourth load. Fig. 12: If a load equal to one and one-half tines the capa- city of one engine is applied to the system. engine “1" will assume twice the load of engine "8" and u" will be carrying full load and 'B" one-half load. . In the above mles. if engine. ‘3' has three times as mach droop as. engine "A", engine "A“ wmld assume three tines as such load as ‘3'. or if it has four times as such droop as ”A“. 'A' would assume four times as such load. etc. Fig. 13: If the slope of line “A“ is reduced, mich is the same as reducing droop, it will be seen that engine ”A" will tend to asstzme a greater share ofthe load. Note that engine “A” is shown fully loaded and engine “3“ has only a snll amount of load. -9- PIA/of PI.” Reduce Dr“; Hiker-ease Deep 0 /——Speed Droop Lever Speed Droop Cam "I ~Speeder Play e Speeder Spring no We/g/rf Fine! Rad ——,. itfensian .— Speeder Rod Riel I--s-— H0! Rod Cmfrot ‘4‘“; l— FUCL to 4—— Engine FIG. I 4- F08( Supply If the "A“ line becomes horizontal (sero droop) engine “A" will assume all load changes within its capacity and there will be no reduction of system speed. The addition of a few parts to the revimsly explained fixed droop governor will permit droop adjustnent by noving speed droop lover as indicated to change can action (See Fig. 14). Load Increase: See Fig. 14. 1. 2. 3. 4. 6. Load is applied to the engine and its speed decreases. The weights nove in lowering the speeder rod and in-, creasing the fuel supply. it the same time the speed droop lever ‘0'” up, pivot- ing at the pivotpin. As the speed droop lever moves up, it reduces speeder spring force, allowing the weights to nave out to pc- vent the fuel change from becoming too great. Since the speeder spring force is reduced as fuel or load is increased, it requires less weight force, or a lower engine speed to balance the spring. ‘ The reduction of engine speed as load is increased is speed droop. Load Decreases Bee Fig. 14. 1. 2. Load is dropped off the engine and its speed increases. The weights nove out, raising the speeder rod and re- ducing the fuel supply. -10- / F/g W391“ Beyer») <——5psed'er Rad , 3W FIStOfl gain/y /—:fi / m ‘ 9 r E p ’7 fi 7 / SUPP, __,, Cesfml / ‘ 77g mm“ Porn/m V lye R-[ot K 01'] Line 1 Finger / ‘ Valve _J . Fbel to Engine 4—— <— Rely FIG. 15 3. At the sane time the speed droop lever moves down, increasing the speeder spring force. 4. Since the speeder spring force is increased as load is reduced. it requires ncre weight force. or a higher engine speed to balance the spring. 5. The increase of engine speed as load is reduced is speed droop. The advantages of this type of Governor are: 1. It is inexpensive. 2. It is simple and has few parts. 5. It has adjustable speed droop. Adjustment of speed droop permits changing the stabilising action of the governor, resulting in a change of rate at which load is autontically picked up or dropped off when the engine is paral- leled with other engines. ‘ the disadvantages of this type of governor are: 1. It is not powerful enough for many prime novers. 2. It is not isochronous. (Not the sane speed regard- less cf load.) ‘ SIMPLE HYDRAULIC arm moor GOVERNOR (SPRING TUMOR DROOP): A change fern nechanical to hydraulic control of the fuel valve in- creases the work capacity of the governor which pernits it to be used on engines with larger fuel pumps and heavier linkage. See Fig. 15. -_ll- 7. The reduction of engine speed as load is increased is speed droop. Load Decrease: See Fig. 15. 1. 2. 4. 6. 7. Load is dropped off the engine and its speed increases. As the engine speed increases the ballarns nove out,- raising the Pilot valve plunger. Raising the pilot valve plunger opens the control ports and allows the oil, unda‘ pressure. to flow to the upper side of the power piston and force it dean to reduce fuel. The oil under the piston is forced out the lower port and escapes to the sump. As the power piston noves down it pulls the speed droop lever down, increasing speeder spring force until the ballaru return to a balanced vertical position. When the ballarns reach vertical the control ports will be closed and the power piston will stop moving. Since the speeder spring force is increased as load is reduced, it requires nore weight force, or a higher engine speed to balance the spring. The increase of engine speed as load is reduced is speed droop. OIL PW SUPPLY SOURCE: Diesel engine governors my be supplied with pressure oil tron the engine lubricating oil pump. but it so, the pressure is usually boosted by an additional oil pulp built into the governor. Pressure 1.“ then regulated by a ”tubs.“ _I [F {a hhkoR “onhtnb A I," Cunnbit \b‘efi me \o maid. (OXW..K \Uxxfi L F L ”Mesafi 5.x 3t ax m e. * OT: as (I .VQKQR VQAKQ O “Ruck MQXKQ K03 ”V m3» Vo\.\ ll.\ SK‘EQQ It. relief valve which met be located at the pressure side of the pump. Changing the direction of rotation of the governor drive shaft necessitates changing the location of the relief valve. Governors provided with an independent oil supply are usually built with a reversible punp. me to a suitable check valve arrange- nent. changing the direction of rotation of the governor drive shaft does not require a change in the governor pimp. Spring loaded pis- ‘tcn type accumulators are also generally provided for storage of a quantity of pressure oil. 81m ammo arm moor GOVERNOR (arm non moor): Another method of incorporating non-adjustable droop is shown in Fig. 16. Load Increases See Fig. 16. 1. Load is applied to the engine. . 2. The pilot valve plunger moves down. the floating lever pivoting at pivot point 'B" and opening the lower con- trol port. This will allow oil pressure to ncve the power piston up. 3. is the power piston moves up, the floating lever pivots at "A“ lifting the pilot value plunger to close the control ports and stop the piston movement. 4. Note that the ballarnn rennin in from vertical which indicates a lower engine speed. 5. Lowar engine speed with increased load is speed droop. -14. Load Decrease: Bee Fig. 16. l. 2. 3. 4. 5. The l. 2. 3. 4. The l. 2. Load is dropped off the engine. The pilot valve plunger moves up, pivoting the float- ing lever at point “B", and opening the upper control port, iaich will allow oil pressure to move the power piston down. As the power piston moves down, the floating lever pivots at "A". lowering the pilot valve plunger to close the ports , and stop the movement of the power piston. Note that the ballam rennin Git from vertical, which indicates a higher engine speed. Higier engine speed with reduced load is speed droop. advantages of this type of governor are: It is inexpensive. It is accurate and sensitive for good speed control. It is simple and has few parts. It is powerful enough for diesel engine linkage. disadvantages of this type of governor are: It is not isochronous (not the .same speed for all leads). Speed droop is not conveniently adjustable. Isocnaonoas (cons'rm arm) HYDRAULIC common: A governor may be built to maintain the engine at one speed regardless of fuel position (load) if droop is used for stability during the had cor- rection, and then gradually rmoved as the engine reacts to the fuel n N. 6Q “\RKDMI \WQ '1' Ugumtm 0..» NUQ J _ rl 2.5.19 luck 3Q llsL \\\\\\\\1 “\wé 23$ , Vonxnpb 1|. All. keys >6 \O @K‘nh. \ . éfiufl A! / Etc.» 9< n\_ norm .3me \ \ x _ 53:on tux QR Mask puke? 1/ $3.qu \ NS Rash.“ W CKXNXQNIU Loamw mtxxnék on?) ”OER E\‘\\ “m on\ ex. crane? some Essen correction and returns to original speed. A compensating dashpot consisting of two pistons. inrdraulically connected, is used to in- troduce the droop action. A needle valve is used to remove the droop by permitting oil to leak to or from the sump. Bpringsz re- turn the droop piston back to original position. For a sumry of the foregoing, two actions are required: 1. A droop applicator, as fuel is changed. 2. A droop remover as the mgine responds to the fuel change and returns to the original speed. The parts required in a governor to accomplish this are: l. A transmitting, or actuating piston, to transfer ac- tion of the fuel changing mechanism to: 2. A spring loaded responding or receiving piston thich acts on parts of the governor to cause droop. 3. A nnually adjustable needle valve in the connecting oil passage of the two pistons which will allow oil to leak off to the oil sump, or in reverse, from the sump to the connecting passage. One type of compensating dashpot arrangement acting on the pilot valve floating lever is shown added to the governor in Fig. 17. Load Steady: Fig. 17. l. The engine is running at nornal speed under stesw load. 2. The ballarms arevertical and the pilot valve floating lever is horizontal. -16- 3. 4. 5. The control ports in the pilot valve bushing are covered by the lands on the pilot valve plunger. The receiving compensating piston is in normal posi- tion. The power piston and fuel rod are stationary and it is assumed the engine is running at approxintely one-half me]. e Load Increase: See Fig. 17. 1. 4. Load is applied to the engine and its speed decreases. The ballarms move in, lowering the pilot valve plunger to admit oil pressure under the power piston. Oil pressure moves the power piston up pushing the actuating piston down. The actuating piston displaces oil to the receiving piston and forces the receiving piston up cmpressing the upper spring, lifting the pilot valve plunger. and closing the control ports to stop movement of the power piston. This action is very rapid and the en- tremely ssmll opening of the needle valve does not allow appreciable leakage. Therefore, the oil dis- placed by the actuating piston causes a corresponding movement of the receiving piston. The power piston has now moved up, increasing the fuel supply to the agine to bring the engine speed back to nornml. 4.. 7. receiving piston to nave down, compressing the lower spring, "lowering the pilot valve plunger and closeing the control ports to stop movement of the power piston. This action is very rapid and the extremely snall open- ing in the needle valve does not allow appreciable leakage. Therefore. the oil displaced by the actuating piston causes a corresponding movement of the receiving piston. The power piston has now'moved down, reducing the fuel supply to the agine to bring the engine speed back to norml. As the engine responds to the fuel change its speed gradually returns to noml, causing the return of the ballarms to the vertical position. Atthe same time the lower spring pushes the receiving piston back to its original position and the floating lever tilts about the pilot valve pivot pin. The rate at which the receiving piston moves up is deter- mined by the null opening of the needle valve. If the needle valve opening is oorreot, the rate of return of flyballs to vertical will be ntched by the rate of return of the receiving piston to neural. At completion of the cycle, the ballaru '11]. be verti- cal, the floating lerver will again be horizontal, the Q 6Q awake,“ NEW luv: \oN Neck Ill. 05th o.» rock \ \\ H\\ Kubxbxnx nix!) hqu 0k EfifitQ W“C.~\\ha (Nahum “figmwgk 9..th tau (oxmfi musk-“SET tbmuvwsfl \ L225 a VMMAWMWV ill \0 bxkkah. ‘\ R \:\Y &\\ .3an ackon‘ Nexufihbm 9.?) \ 3.x P... 8Q h , Ms control ports will be closed, the receiving piston will be back to its original position, and the power piston will be down at a new position supply- ing a smaller quantity of fuel to the engine for the TWO“ lads NOTE: Two springs are used to center the receiving piston in the previously described governor. Actually, most governors use one spring acting in both directions to accomplish the same result. Another arrangement of a compensating dashpot system is shown in Fig. 18. In this case the actuating piston is directly attached to the power piston rod and the receiving piston is attached to the pilot valve bushing. Lad study: F180 18. 1. 3. The engine is running at norml speed under steady load. The ballam are vertical, the control ports are closed, and the pilot valve bushing is in norsml position. The power piston is stationary and the engine is running with approximately one-half fuel. Load Increase: Fig. 18. 1. 3. Load is applied to the engine and its speed drops. The ballarsn move in lowering the pilot valve plunger to admit oil pressure undathe power piston. As the power piston moves up, the actuating piston also moves up (the pistons are on the same rod) displacing oil to the top side of the receiving piston and forcing 4. the pilot valve bushing down. This closes off the control ports to stop movement of the power piston and empress the lower spring. This action is very rapid and the extremely small opening of the needle valve does not allow appreciable leakage. Therefore, the oil displaced’by the actuating piston causes a corresponding'movement of the receiving piston. is the engine responds to the fuel change its speed gradually returns to norml as indicated by movement of the ballarn back to the vertical position and the pilot valve plunger moving up. At the same time, the pilot valve bushing is pushed back up to normal position by the lower spring as the oil escapes through the needle valve. lhen the cycle is complete the ballarn are vertical, the pilot valve plunger and pilot valve bushing have returned to their norsml positions, and the fuel supply to the engine has been increased to handle the increased load. Load Decrease: Fig. 18. 1. 2. Load is dropped off the engine and its speed increases. The ballarsn move out, raising the pilot valve plunger to admit oil pressure to the top side of the pm piston. ~21- 5W adjusting Knob or L e ver Speeal a4j'057‘l'ng Screw / ? fi / mg m / Speeder / Plug Speeder Spring 0 I 0 FIG. 19 —_— 4. It 1. powerful. 5. It operates without permanent speed droop. The disadvantages are: 1. Higher cost. 2. It normlly has no droop and cannot be used for divid- ing load in parallel operation. (Two or more engines driving the same shaft or on the line in an electrical system.) A pernnemt droop attachment my be added to this governor to elimitmte this disadvantage. In the foregoing explanations of operation the amount of move- ment of the governor parts has been greatly exaggerated as would be the case with extremely large load changes and consequently with large speed changes. Actually, in ml operation with ordinary load and speed changes the movements of the parts wmld be consider- ably less ht, naturally, would be proportional to the amount of load or speed change. 8P8!) ADJUSTMENT: In the foregoing discussions of operation, speed changes as a result of load changes have been comidereid. The same sequence of governor movements would occur if a speed ad- justment change had been made by changing the force or compres- sion of the speeder spring. ‘ The' speeder spring force is adjustable on nearly all governors. One type of construction is sham in Fig. 19. The upper end of the spring fits into a speeder plug inich may be adjusted up or down by means of a lover or hob on the outside of the governor. -23- [cad limit screw /‘LOCkNUt Power PIS fan 0/! pressure Supp/fed by E—J Pi/Ot Valve FUel Openiry [la/ye limifed {a Miss amount Fuel to Fuel Engine imp/9 9&20 HMIIII }\ Load Iimil‘ Screw lock Nut" 74,1 Rad \ g 76 PW”, : ‘ / jar/0g C/osed § §/( 1.071? Halve é \ r \ 6 Powr Pis tan é§ \ // /§ 4 4} §// / \/ / \\\\\\ § / r g 01! Pressure / / Supp/18d g by Pilot Kv/ve Q 2 Z; ' Ho. 21 Fuel Valve 0.0th +— /I'ml'f'd {a {/7 1'5 / also an 2" .g | . l A reversible motor controlled from a switchboard may be used to eliminate animal speed changing. The motor operates to harm the. same screw that changes the speeder spring load. Reducing spring force reduces the speed of the engine. Increasing spring force increases the speed of the engine. If the engine is paralleled with other units, adjustment of the spring load will cause a load change on the engine. Reducing spring load will reduce load on the engine. Increasing spring lead will increase load on the engine. WICALLOAD LIMITING: Excessive load on the engine any be limited by rem-nun; the rum aunt of fuel that the engine may receive. Fired stops on each of the engine fuel pumps, or a fixed stop on the fuel linkage to the pumps my be used, but this mechanism may be incorporated in the governor to reduce the m» of parts in the engine. See Fig. 20. The power piston is shown up against the limit screw and the fuel control valve is open as far as the screw will allow, in spite of the pilot valve supplying addition- a1 oil pressure. HYDRAULIC LOAD LIMITING: This mechanism limits load on the engine in exactly the same manner as the mechanical load limit, but is adaptable to sunny different types of raote control. See Fig. 21. The fuel control valve is shown open to maximal load. If oil pressure frm the pilot valve attempts to increase the fuel opening (raise the power piston) the tail rod and limit valve will remain as shown and the oil pressure will bleed off through the valve to .2 4.. N N oak It 1:11 I .f V \ \ \ u \////a\ :3 \ 1* 3:09 I \ \ ' \\ +\\\t ,& Tutu“ 1‘ NKOQ\B\\:.V T‘O m\§.wi f \ x m med You. :8 Tu M\ Eaton aminmx !\ l I 33.. north maxkoxu. tabxmk .In\ \\\\\\\\\\ mIN 6Q \SQ \ekweob 1MB Ea ”~93.ka mahnmfikk hwxxckktob \oVoo >5 \o «in. :3 mi amiofi 0\bWMbKQ ktfixmtob 5nd Pequot Nu“ RS3“. U§\§\— ”\Vflflz tfiq mtmixoook LUMSQQ / 9.3. ”RS \ \ ooh. koaww $3.qu 3.x 3.x the top side of the piston and to sump. When the limit valve re- leases oil pressure node the piston, the piston cannot move up further. An air operated piston, solenoid, etc. , my be used in place of the load limit screw to ruotely apply the limiting effect. TYPE OF PILOT VALVE AND POWER PISTONS: There are three types of pilot valves and servcmotors used in governors. Only one type, the double acting valve, has been shown in the previously explained governors. 21m DWBLE ACTING pilot valve (see Fig. 15 to 18) controls pes- sure to both sides of the power piston. The pilot valve plunger has two lands, each one covering ports to control oil pressure. Oil pressure supply is trapped between the two lands and is redeased to the top or bottom of the power piston, depending on whether the pilot valve plunger is moved up or down. THE SINGLE ACTING pilot valve (see Fig. 22) controls pressure to one side of the power piston to exert force in. the direction to increase fuel only. A return spring is provided on the other side of the power piston to exert force in the direction to reduce fuel. The plunger has two lands, but only one land controls the oil pres- sure. The other land seals the oil pressure in the bushing. THE QIFFERHTIAL pilot valve (see Fig. 23) controls pressure to the bottom side of the power piston also, but constant oil pres- sure is used on the top side of the piston to exert force in the direction to reduce fuel. .2 5- If the pilot valve plunger moves up, there will be oil pressure on the top side of the piston only, and the bottom side will be open to sump which results in the piston moving down to reduce fuel. If the pilot valve plunger moves down the same oil pressure will be on both sides of the piston and the piston will move up. The greater bottom area of the piston results in a greater upnrd force. OTHER AUXILIARY DMOE: Special auxiliary governor devices, other than lead limiting, have not been described because of the innumerable variations encountered in diesel engine governing. It is sufficient to state that all auxiliaries operate to produce some action or to restrict action of the speeder spring, pilot valve, or power piston. -2 6.. (II) ammo MECHANISM OF mum. mom «kwhuxx A. .meq \mxtmb 061m Q0 MN toxwm twfixt tifixh. to \XBQK \ U VQQ Lawn WSTU .hkxv‘rU 3&me \QQQ VQWVV \Q SanGq “333%! $33va .VN 6Q wiflu duck $6 mioékufim, gnu um.:<\ WES uhotrxlm. . e .\m “a.% O ”2%.; WA tr?b e; 23.; b V d/ is fix .V \ REVERSING MECHANISM OF DIM “CHINE The difficult problen.of quickly reversing the direction of rotation of marine diesel engines has been completely solved in both four and two-cycle engines. It can be more easily effected in the latter type owing to the lesser number of cylinder head valves, but efficiently in both. In four-cycle engines the various head valves are in nearly all . oases operated by ten sets of came, one for "Ahead? and the other for 'Astern" running. In most designs, the two sets of can are “lit“. on one shaft, the “Ahead" and lAsternF cans for each‘valve being adjacent. Although two sets of cans are almost exclusively adopted, it is not the only method possible for accounplishing the reversal of four-cycle engines; it is, however, the only method adopted in urine practice. To reverse the direction of rotation of a four-cycle engine, the engine must first be stopped, then.the'valve levers raised clear of the cans to allow the cam-shaft to be moved in an end-wise direction, so that the rollers of the valve levers are directly over or in line. eith the cams that correspond to the reverse direction of rotation. After the can-shaft he been moved to the desired position, the valve levens are returned to their running position.ehen.the engine is ready for starting in.the:reverse direction.tc that of the preceding run. Fig. 24 shows the relative positions of the various ‘Ahead' and 'Astern‘ cans of a four-cycle engine. ill. . Lire, fiifiltlalfl!n..4flbk;i 11' 21:11:] in]: j E c~ ? 8. FIG. 25 Reversing Medan/5m for Four-cycle E lyine . "I .‘5 . — r 1"le r.§__.'-.—-—'-'U' [##J Roller -—\ Asfern Cam Cam FIG. 26 View of Projecf'z'ng Cams Shaw/03 C/earance necessary for Re vet-gal This is the principle upon which nearly all four-cycle engine reversing gears work. The means adopted to carry out the various operation vary only in the different sakes. The gears described in the following pages are the nest oomonly used. A simple and reliable method of reversing a four-cycle urine engine is shown in Fig. 25, which consists of a horizontal cem~shaft placed near the bottom of the cylinder. The can (e and s) actuate the valve levers through long rods comonly called push rods. The crank-shaft (a) runs the entire length of the engine with a small throw crank for each cylinder. To each crank, four small levers (b) are attached by bearings, one each for the fuel" injection: start- ing air, air induction, and ssh-net valves. On the can-shaft are two cans side by side for each valve, one being for "Ahead” and the other for 'Astern“ running, and to bring the regaired can in line with the lever roller, the cam-shaft is moved in an end-wise direction, an anount equal to slightly more than the width of the can. mm. the can-shaft is being noved in an end-wise direction, it is necessary that the rollers (c) should quite clear of the cam. Otherwise, the peak of the can on which it is desired to work my be on top, or in open position, in which ease'the roller would foul the can (see Fig. 26). To prevent this, the crank-shaft (a) is given one complete revolution, which, as my be inagined, swings the rollers clear of the can, while the cam-shaft is being moved longitudinally. Both the above described operations are carried out by a snll air turbine, connected by gearing to the shaft (a), or by a servo- nctor, to which is connected a rack gearing with a pinion fixed to .28.- the shaft (a). For operating either of these nachines, it is usual to employ compressed air at a p'essure of about 350 lbs. per square inch. The longitudiml movuuent of the can-shaft in the gear illus- trated is obtained by a disc or collar, fixed on the can-shaft, work- ing in a groove out in the face of the drum (d) keyed to the crank- shaft (a), the groove being slanted as shown in the illustration. In the later engines of this nke, one stroke of a rack as described above rotates the shaft (a) one revolution, and at the same tine, moves the can-shaft longitudimlly by means of a slanted groove out in the back of the rack. On stopping a diesel engine, some of the cranks will come to rest in such a position that there will be a pressure left in the cylindc. To relieve this pressure and facilitate starting in the reverse direction, means are usually provided to ease the exhaust or escape valves off their seats during the reversing operation, thereby allowing the success of pressure to escape. Another reason for breaking the compassion in diesel engine cylinders is to pre- vent dange to the induction and exhaust valve operating gear during the reversal process. Suppose, for instance, that an engine stops when one cylindn' is full of air or gas under wessure. For the reverse direction of rotation this last stroke of the piston may have been the exhaust stroke instead of the empression or the firing stroke, in which case the exhaust valve would still be partly open, since it is not timed to reseat until about 10 degrees after top center. Even had the crank gone beyond top center and the exhaust \ Err/must Va lye Lever- \\” F"""“ O O (’i L J "\ —— FIG. 2 7 Mechanism for 5051319 Elba/st Va/Ve period been completed the air inductim period would have begun, which means that one or another of these valves would have to be opened during the reversal process against great pressure. In a 30-inch diameter hylinder having exhaust and induction valves of about 10 inches diameter, the load to be overcome would be very great, so that the necessity for breaking the compression will be appreciated. The rocking levers are usually strong enough to accom- plish this, but when push rods. are deployed, these waild need to be extremely heavy, so that with such gears, special provision is usually nde. In reversing gears Just described, the exhaust valve is eased off its seat by means of an arm (a), Fig. 27, supported by a pin screwed into the cylinder cover and attached to the push rod as shown. From the sketch it will be seen that during reversal, as the push rods are swung out to avoid the rollers fouling the came, the top of the arm (a), being cut at an angle, will lift the lever and ease the exhaust valve off its seat for a tine sufficient to allow afar gases in the cylinder to escape to the exhaust passage. It will be obvious that when the exhaust valve is closed and the posh rods are in running position, the relieving arm (a) should be quite clear of the valve rocking lever, otherwise the valve would be prevented from reseating properly. Consequently it is necessary after a change of exhaust valves to check this clearance and adjust by means of the eccentric pin (c) if necessary, otherwise the compos- sion will be low and the engine difficult to start. -30- \7”,' ______________ L I! I ' | I l 1 :1 L L 7— FIG. 28 Eveumatic Der/be for falsity Rollers Clear 0f Cams during Reversa l. . Another nethod of raising the rollers high enough to clear the projecting can, as the can shaft is ncving longitudinlly, is shown in Fig. 28. This consists of a small piston working inside a cylinder con- nected to the valve casing. During reversal, compressed air is ad- mitted to the snall cylinder, and forces the piston downwards against the pressure of a light spring. A projecting stem opens the exhaust valve, and thus raises the roller end of the rocking lever clear of the can before the cam-shaft is moved. “has the cam-shaft has been moved to the desired position, the compressed air in the small cylin- der is released, and the valves allowed to return to their working positions. At the same time, any pressure left in the cylinders frm the previous run is allowed to escape through the open valves. A. four-cycle engine which has a double series of can mounted on separate shafts, is that formerly marmfacimred by Cooper-Bessemer Corporation, Mount Vernon, Ohio. In this engine the two cam-shafts, one for "Ahead" running and the other for ”Astern", are placed side by side and revolve in bearings combined 1n one casting, which is free to move in a cross-wise direction. These coatings are connected by levers to a small crank-shaft, which is operated by a reversing motor, to bring one or other of the cam-shafts, according to the de- sired direction of rotation, under the valve lever rollers. In the four-cycle engines nnmfactured by the Fairbanks-Morse a: 60., the method of bringing the reverse came into ruming position is somewhat unusual. There are the usual “Ahead" and ”Acton“ can: -31- kcomv m3?! OW thoST chttQ‘QQK % N .oQ sun when . F n nsV Q i \H n . _ , . I I- “ Z ,, “been - . . 7 , , nnsmfloxmk I 1¢ , /U// A mum 3am l- mammamxmk mamted side by side on the cam-shaft, which is moved in an endwise direction as in other designs, but the novel feature lies in the fact that, instead of moving the lever rollers to clear the came, the cam-shaft is moved to clear the lever rollers (Fig. 29). When it is desired to reverse this engine, the cam-shaft is lowered bodily, then moved longitudinally to bring the rererse come into position, after which the com-shaft is raised and returned to its running position. This operation is carried out by admitting compressed air to a cylinder which acts through a rack and pinion (B), Fig. 29, the pinion being scared to a lay-shaft or reversing shaft located beneath the cam-shaft, and the rack to the air motor as shown. The cam-shaft is free to move radially about the point (I), and is supported in position by eccentrics (E) under each cam-shaft bearing, keyed on the reversing shaft. As the reversing motor begins to move the rack, the reversing shaft is rotated, and since the cam-shaft rests on the eccentrics (E) on the reversing shaft, its position during the first 120 degre- of movement of the reversing shaft is lowered about 2 inches; the cams being now well clear of the lever rollers, the cam-shaft is next moved in an endwise direction. This is effected by means of a scroll cam (P) secured to the reversing shaft, and toothed quadrant (W) gearing with a grooved drum (H) on the cam-shaft. The rotary movement of the scroll causes the cam-shaft to be moved the desired amwnt in an endwise direction. One stroke of the revers- ing motor rotates the lay-shaft through one complete revolution, the latter part of which returns the cm-shaft to its original position. .32- , I.” no . Q Jo Fe. m, . 7 v. a Q. n . acne is. .. veua . lee-9! . / uses rising ~ '29 .. . s a Cat- .5s»s3 9.. P; W Q. O‘ I} I .1.“ . l .. z ’u Career- .luree ' '4’ Steam Idlu. 11' it...“ a . I.” . use, lute; flee-5:! 0. Oscar»! e _. 93!;- . . .. .4 eats. .... ea! .w e . av . a sale. a. I 9 [I O a. .n . . . . x . . a . . 3.. m1 . _. .. . . 1 3r... 4 . . .9 . r .4553!le 11, - . I - Ll*us*~. e / . _ . . h. . Idea! 1 .u. . . ._ . .5 .. - ole-Solos. . . Hi... age. .. _. . ”.3. . .u.‘\. 0 h I . 1 Is I .r . gfl._ ../ 4/1/ vase): .r. . (“1... r .r pate»; v r . [real->10»; . a . a I 1.. u . z . J I 0 Is I ma.— _ '9.an gifqr a. . .\ .- Zest-3. 7 ale-Se! / . he .. ._ a apocalypse-actors {\J . lawn.» _ I .. .. 7. 3 9.1..- r. e. B!!! .u 85»! ,. . s egos-2a?! a. 2 . lose-supine a. / . nurses?! 9!. .. . hint-lg 9.3.65." .. J .. . specifies}: .. 1 . . _ gel - \81 a. \o/ no.5- w . . a a . {I . L 0 I . V I n _. n n... ..... ,, x. . guinea»... all?! a k v/ .. . _ /.n+u a . 839394.? n- if eiieoladelesiee /.,. a”. - - 4. \s . a a _ awn-eel»; Inst... .3353 sands-stats . a. . h r... o , arouse lasts-spears.- fl III-firgpee versed-casings: a. an N ’ rt'. # Is 0 . I ..,;I/ . Eh. .. / v .38 ,1.» ,. e . . fl .. ,/ L s xv // .. a L .- / (/7 _ i n . u (s . fl . r s can. .5 .H . n “W... l/ .-r n . 4/132/ m Lind: .. I fa ,a .,., 4.-. . , . .. O I ,.,. . .v. . .. . f .u. i / . litteeepaaigae : 1,. .Ar...;ls m J . I / a/ h _ I / z. . r W “I z/ n /,/v a! lace:- I. also! /\/ . Saul-lat i The position of the toothed quadrant (W), as shown in the sketch, is obviously incorrect, it having been drawn in this way to'simplify explanation. Its actual position is at the side of the grooved drum, since during reversal the shafts approach or recede from each other. We will new deal with the reversal of two-cycle engines, and first of all describe the gear on a Nordberg-Dieeel engine, as shoisl in Fig. 30. The correct timing for the in; ection of fuel and starting can for ”Ahead” and 'Astern“ running of the engine is accomplished by turn- ing a. can-shaft (l) relatively to the crankshaft by means of a dif- ferential gear unit in differential spider (z). The differential drive gear (3) is driven from crank-shaft by a gear and idler gear which are not shown on the drawing. The drive gear (3) is bolted to the reversing bevel gear (4) and rotates the differential pinions (5) vhose shafts are semred in differential spider (2) which is held stationary by spring loaded roller (6). The differential pinions (5) drive the reversing bevel gear (7) which is bolted to the camshaft drive shaft (8) and gives the correct speed and timing to the camshaft (l) and fuel pump can (9). lhen re- versing, the differential spida' (2) is moved from "Ahead” to 'Astern" position by link (10) and reversing bevel gear (4) driving differential bevel gear (7) which moves the camhaft (l) to the correct ABTERH posi- tion. The normal stroke of the reversing piston causes the camshaft (l) to turn approximately 108°. A spring loaded roller (6) looks the differential spider (2) in the ”Ahead" or "Astern' position. -33 .- 4 3 2 I mouths-Macadam ‘ ‘DJ'IS'NC air. '0“ minus 9 O A... 3., p m, “I V ‘ w m as; '°" 2 I O l 2 3 I J - ____._ x- g “ / x ‘ i L Luna L1 L ,~ N (1 m m K. .‘ ‘k‘j - '7" 1 .V awe-a rap? use owns t. L ."ngmnvmmfi 1 V J svaav. may M are. 3”? MO? “I (“3 N011. . 1*!th laws as ( own-0‘ an: an eon. -o Mum-so on Home on i our-lot menace-sea a "S unmet insure Dons '15! a0,- lsvm'. 'A'."* -N"m ".a now“ run was *0 We? mm m as m: MM cm uvva m‘vcr'voaavvon w'w - a-A a. H-[r'fl'v'rm a'. serum .1“ Mt 3:.an races (nan-(a SWIM" 5' In!” I 'v- A-erwr. Ami-ritual. '1' '0' Yo mgs m Msv gr"). 5:; nun 0 use a. a m ar'n P’MOCYFI'IN (00‘qu LIVIIAID newton mews mm! tau." 5 3w» r .. “an!“ an “A" 0 3n hear av mac. cm MM twufsf'fll mo ()fl'I'RIN' «Au/v '. en” orhn 06'.th am 4“ rvy AAAA-AA r‘rvi‘v‘r. L; w" s... cm: rm sevens «Autumna- 1.1M! v me. ya. a s as waves new / e A .1 ,. A A a 4 J 4 A ,4 _. A _i._ ‘ su' ‘ a: 4 o 1 > E5 4 .- 1; FIG. 31 . r‘ . Mamas oerIus Two ; « - j CENTRAL CONTROL up 7 -. , 3 - «" STAND AND Pix—or U VALVES. WWW! , 31m. "LOT“ DETAILED DBCRIPTION FOR AHEAD STARTING: (Fig. 30) As the min shut-Off valve (12) for the starting air is opened, the air goes through pipe (13) to starting pilot valve (14) and through pipe (15) into bottom of autcnmtic starting valve (16) messing valve (17) against its seat. With the main shut-off valve opened farther, cham- ber (18) and pipes (19) are also filled with air. The control lever on control stand is connected through links and a gear sector to control shaft (20). By moving control lever to “Start" position, control shaft (20) is turned and “Ahead“ starting cam (21) lifts starting pilot valve tappet (23) thereby venting pipe (15), causing piston to autcutic valve (16) to move down and open valve (17) thus admitting air throlgh header (22) to the cylinier starting valves (23). At the same time air is admitted through pipe (24) to the starting air timing valves (25). The timing valves are - pushed in contact with starting air timing can (26) which tin the opening and closing of the cylinder head starting valves. At least one of the aiming valves opens the passage for air through pipe (27) to the top of the respective starting valve (23) which is thus opened and admits air to the cylinders from header (22). The engine starts running ahead on air. The control lever release is pulled and the control lever can now be moved into the FUEL range. Before the engine receives fuel the “Ahead" starting cam (21) (trips the pilot tappet (28), (approxi- mately 7/16" after position 3-see Fig. 31) which permits the valve to return to its seat. The vent of starting pilot valve (14) is closed again and connection between pipes (13) and (15) is estab- lished. Piston in automatic air valve closes valve (17) thereby shutting off the starting air to the cylinders of the engine. As valve (17) closes, piston valve (29) opens, and header (22) and pipe (24) are vented. DHAILED DBCRIPTION OF REVERSI‘NG GEAR AHEAD 1'0 “TEEN: A! mentioned before, the camshaft can be reversed if necessary before the engine has come to a stop by moving the control lever beyond the STOP position tourd “Astern” as far as it will go. The motion of the control lever is blocked by the ridge of astern reverse cam (30) striking the ahead to astern valve tappet (37). This can also opens the ahead to astern reverse valve (31) which admits air through pipe (32) to the top of reversing cylinder (33), forcing reversing piston (11) downnrd to the bottom (Astern) position. When reversing piston (11) approaches its bottom position, re- verse cam unit (54) is shifted along control shaft (20) by means of shifter roller (35), which travels in interlock cam (36) secured to the differential housing the reverse cam unit (34) noves until re- verse cam (30) clears tappet (37). Ahead to astern valve tappet (37) then trips, shutting off the air supply to the reversing oylinier (11) and releases the control lever so it can be moved to START position. By doing so, the astern starting cam (38) on control shaft (20) lifts starting pilot valve tappet (28), thereby opening valve (17) adm'tting air through header (22) to the cylinder starting valves (23). ~35- (.2! 5‘ The. which are operated through the starting air timing valve (25). The starting valves admit starting air to the cylinders of the engine and bring it to a stop if it is still running ahead and then start- ing it in astern direction. As soon as the engine has reversed its rotation and has snde two or three revolutions, the control lever release is mlled and control lever is moved to desired FUEL ASTmN position. When moving the control lever to FURL position, starting pilot valve (14) shuts off the mappdy of starting air. nesh pet (39), which is supplied with oil fmn the lubricating oil system, cushions the motion of the reversing piston. Throttling valves (40) in the air supply lines (32 and 41) also retard the notion of the air cylinder. -36- eJiLflIMN-é . ... w} a e a a (1) (2) (3) (4) (5) BIBLIOGRAPHY “Governors and the Governing of Prime Movers“ by w. Trinks. ”Governor Instructions" by Woodward Governor Company, Rockford, Illinois. "Imtruotions for Operating and Maintaining Nordberg lurine Diesel Engines" by Nordberg mnufachlring Company, Milwaukee, Wisconsin. "Diesel Engine Instruction Book“ by Fairbanks, Horse 8: Co., Beloit, Wisconsin. "Instructions for Operating and lhintaining Cooper-Bessemer Marine Diesel Engines“ by Coope-Bessemr Corp., Mt. Vernon, Ohioe 92hr... i nevlddhsn(-v4§|: .1 v - .I‘Il .‘Jil.'lev.(6..«’e 0.4:Iu r . .n s. I l I A I - - .\ -I‘ - i tut”, - i . a . . v . . . y t b 1 ti. .n .I n (1‘ . «$1.4, u .- lidf I ‘Y-itfi|' . 0". Qv‘ltde‘i‘lii!‘ 1 0.99) .‘Ii'llei .a e , ( um e r v . u Isl , . . . e . . .. v Q l s ' .il it! . :s: e n'.v|. rift-s..-) I is. . . .