US2678402A - Acceleration control device for engine-generator sets - Google Patents

Description

y 11, 1954 A. 1.. ALTEMOSE 2,678,402

ACCELERATION CONTROL DEVICE FOR ENGINE-GENERATOR SETS Filed June 7, 1951 3 Sheets-Sheet 1 Emu w "w" W INVENTOR. ARTHUR ALTEMOSE A T TORNE Y.

May 11, 1954 A. L. ALTEMOSE ACCELERATION CONTROL DEVICE FOR ENGINE-GENERATOR SETS Filed June 7, 1951 3 Sheets-Sheet 2 INVENTOR. ARTHUR L. ALTEMOSE.

A TTQQNE Y.

May 11, 1954 ACCELERATION CONTROL DEVICE FOR ENGINE-GENERATOR SETS Filed June 7, 1951 A.L.ALTEMOSE 5 Sheets-Sheet 3 INVENTOR. ARTHUR L. ALTEMOSE.

ATTORNEY.

Patented May 11, 1954 ."PATENT OFFICE AGGEIJERATION CONT-ROB DEVICE-FOR ENGINE-GENERATOR SETS *ArthurL. 'Altemose, Williamsport, Pa., assignor -to -=Avc '-Man'uifacturing' 'Gorporation, Ginoin- .:..nati," Ohio, a corporation 'of Delaware Application. June 7, 19.51,.Serial o...230,407

1 7 Claims. 1 The present"invention relates "to a control mechanism for regulating thepower outputiof *anengine driving energy "producing: means; such --as a plurality ofelectrical generatorspMore specifically, this invention 1 concerns a combination-of electrical"andmechanical elements'which are adapted to'control the rateof loadingrof' an engine generatorset.

*Formany years portable engine generator sets '-'ha-ve-'been used-forsupplying' electrical energy'to auxiliaries'andare coming into wide spread use --forstarting jet aircraftengines.

Insuchengine generator sets, it" is commonplace to provide generator capacity having a maximum output which is substantially equal to the-rated full load outputof the "enginewhich "may bean internal combu'stiomengine, such .as an Otto engine. In these sets," it: is important that the engine beloadedat a ratethat "permits the engine'to accelerateto' its' maximumrrated "speed at whichfull power output" can'zbe. de- --veloped. Should the load; beappliedat. an'excessive rate, stalling mayoccur which'is obviously highly undesirable, particularly when a' jet engine must be started which is-urgently'needed'ror military purposes.

The present invention comprises an extremely simple, effective control "mechanism that" 'prevents improper-loadingof an enginegenerator set and makes it-pos'sible:to--impose avery large loadinstantaneously on the generators without stalling the engine driving-"th -"generators;"' The I mechanism ot the present inventiontemporarily breaks the circuit of-one of thefgeneratorsiand permits rapid acceleration" of 1 the engine until full: operating speed is attained at-which gtime the-generator circuit is reestablishedsoxthatz'the generator can assume its proportionate share. of the load. Such a method of operation-not only prevents stallingandpermits very. rapidacceleration of the engine but also insures thatthe full generator loadwill'only beimposed'onthe'engine when it is'operatingat aspeed at which-sufficient power can-badevelop'ed.

" 'Briefiy 'statedjthe present. invention compre- "hends -the provision of an'electric'al switchjn the. control circuit of oneof apluralitypfrgenerators.:driven" byithe engine. This switch. is co- "operatively"positioned relative to a speed: regulatingfigovernondriven by the engine." The governor regulates the'throttle valve. .position of a charge forming means or otherfuel' flow regulating device forthe'engine. The switch is actuated 'bythe'governor when it. opens thezthrottle valve t e'an"e'xtreme -wide open position beyond the position 'assumed by.thethrottleduring ordinary operation, even atflfull loadfiWhenfthusactuated', the :switch" temporarily breaks "the ZCOIllilOl "circuit "of one" ofthe generators rendering itin- 5. effective. for generating. electrical energyg'Thus partially. "relieved Of'itS. load, the engine can rapidly accelerate'in" speed. Wheniull :spe'ed hasibeen'attained, the governor. moves. to close the'throttle .valve and theswitch is disengaged. 10 'As a result the .control'circuit ofthe generator is-again 'completewmaking it possibl for the egnerator "to: assume 'part of "the load :and. for equilibrium to' be" established with the. engine developing full power output at maximumrated 7 speed.

The present-invention is particularly useful-in conjunction with. an engine, generator'set al- "though it "should beappreciated :that it can also be usedto advantage for controlling other-in- -stallations whereian engine drives a power'consuming'elem'ent, such as a.pump. "Thepresent "inventioncan beadaptedfor 'uSe'in such instal- "latio-ns through, theprovision'ofan; electricalcir- *cuit controlling the .output of the pump'or comparable element.

ZIII view of 'the'foregoing, it'is'an important :object of the "present invention toprovide means for controlling the ratezof loading-of-an engine in anen'ginegenerator'set so thatstalling of the "engine, :as' it is loaded," is prevented.

' A further object of the invention is theprovvision of an, electricalcontrol mechanismactuatedby an engine governor wherebythe loading of 'anenginegenerator set is:controlled so that stalling" is prevented and rapid "acceleration. .is permitted.

'Another important object of "the 'present in- -vention is toprovide a'control-mechanism for an enginegenerator set that prevents overload- 40" in 'of. the set.

Morespecifically, it is anobject of thepresent invention toprovide a .controlswitch in .thecon- 3 trol'circuit' ofroneof aplur'alityof generators in .an engine :generatorset; the switch being ,actuated by a multispeedgovernor as the governor moves the fuelregulating means. of theengineto its. extreme wide .open position, actuation. of the switch. temporarily rendering. ineffective one. of L the generators. for producing electrical. energy.

The. novel. features that are. considered, character'istic of. the. invention areset. forth in. the appendedclaims; the .invention itself, however, vbothastoits organizationandmethod of operation, together with additional o bjects and-.ad-

' vantages thereof, will best be understood from the following description of a preferred embodiment when read in conjunction with the accompanying drawings, in which:

Figure 1 is a side elevational view of a complete portable engine generator set, the access doors of the set being shown in their open positions to facilitate illustration of the interior construction of the set;

Figure 2 is an elevational view toan enlarged scale of the carburetor of the engine in conjunction with a multispeed governor and an electrical switch associated with the electrical circuit of one of the generators of the engine generator set; and

Figure 3 is a schematic wiring diagram showing the electrical control circuit of a pair of generators included in the engine generator set.

The mechanism of the present invention is particularly useful for controlling the rate of loading of an engine generator set, generally designated I, illustrated in its entirety in Figure 1. Engine generator sets of this type may include ground wheels 2 to permit transportation around airfields where the set may be used to start aircraft engines.

The set includes a chassis 3 on which body 4 is mounted, the body including access doors 5 and 6 which have been shown in their open positions to facilitate the illustration of the interior.

The set includes an engine 7 which drives generators, generally designated 8. A pair of generators has been shown for purposes of illustration, although it should be appreciated that more than two generators may be provided if desired. A fuel flow regulating device, or a charge forming device such as carburetor 9, is provided for engine I.

Engine generator sets of the type illustrated may be used to supply electrical energy for the starter motors (not shown) associated with the aircraft engines to be started. Normally the set idles at a relatively low speed until such time that the starter motors are connected to generators 8. Imposition of this load on the generators causes the engine I to slow down and a governing mechanism, to be described more fully hereinafter, adjusts the throttle settin of carburetor 9 to increase the speed of engine 1 until full power output can be developed and the generators t are supplying desired current to the starter motors of the aircraft engine being started.

The mechanism of the present invention is shown in detail in Figure 2 in which carburetor 9 is fully illustrated. With reference to this figure, r

it will be noted that the carburetor includes a pair of throttle valves I0 and II in series. The particular carburetor illustrated is of the down draft type, air being aspirated through its upper end, the air picking up fuel during its passage through the carburetor to form a combustible mixture which is supplied to engine 1' through an intake manifold, a portion of which is indicated at l2. The quantity of fuel air mixture admitted to the engine is controlled by throttle valves It and II which are pivotally secured to transverse shafts I3 and I4, respectively. I

The position of throttle valve I ll may be manually adjusted by means of an associated arm I5. This throttle valve is used when the engine is first started after which it is moved to a wide open position indicated in Figure 2 in which position it remains durin the time that the engine is in operation and under governor control.

Throttle valve II is adjusted by means of arm IS the position of which is controlled by a multispeed governor, generally designated IT. The governor is driven by the engine through splined shaft I3 and is driven at all times at a speed proportional to engine speed.

The governor may be of any conventional type suitable for the purpose but preferably should be of the fiy-ball type which operates to maintain the associated engine at a constant speed of operation, this speed depending upon the governor setting. This setting is determined by the position of a bell-crank is which is p vo a y attached to the governor as at 29. The position of bellcrank it determines the tension of spring 2I and, as will be described more fully hereinafter, pie-determines the governed speed at which the engine will be maintained.

Governor I'I imparts swinging movements to arm 22 about shaft 23. As the engine speed decreases from any pre-determined speed setting, the governor swings arm 22 counterclockwise thereby opening throttle valve I I by means of interconnecting link 24. As the engine speed rises above the pre-determined speed setting, arm 22 is swung clockwise to close throttle valve II and reduce the operating speed of the engine.

The swinging movements of arm 22 are controlled in part by the tension of spring 2 I. Thus, as bell-crank It is rotated clockwise about pivot point 2d, spring ii is stretched and its tension is increased. Simultaneously, the increased tension of spring EI tends to move arm 22 counterclockwise and open the throttle valve. Correspondingly, the engine speed increases until the forces developed within governor I? are sufiicient to overcome the increased tension load of spring 2 I. When this condition has been attained, arm 22 is moved clockwise and the engine generator set comes to equilibrium at a new operating condition, at a speed higher than that which prevailed prior to the time that bell-crank I9 was moved in a clockwise direction.

The specific mechanism for rotating the bellcrank constitutes no part of the present invention and has been described and claimed fully in Patent No. 2,622,576 entitled Two. Speed Engine Governor issued to A. W. Rickenbach on December 23, 1952. For the purposes of the present invention, it is sufficient to understand that governor I! with bell-crank I9 and spring 2I constitutes a multispeed governor which can be adjusted to establish pre-determined constant operating speeds at which the engine will be held under various load conditions.

Governor I'I per so may be a conventional flyball governor such as is commercially available.

Positioned immediately below governor I I is an electrical switch 25 having projecting switch actuating arm 26 which is positioned for engagement by arm 22 in the course of its movement. Switch 25 is adjustably secured to bracket 21 which projects from and is rigidly secured to a fixed engine mounting plate 28. If desired, switch 25 can be located elsewhere on the governor or carburetor in position to be operated by arm 22 and the associated linkage.

With specific reference to Figure 2, it will be noted that actuating arm 26 is engaged by arm 22 when it is in its extreme counter-clockwise position at which time throttle valve I I is held in its extreme wide open position. With reference to this same figure, it will be observed that arm 26 is disengaged by arm 22 when in its dash line position at which time throttle valve II is in a pars 'ti'ally open' position; -zost"indice;t'ee fsinrzphgnf lines.

' with reference to Figure 3, the control. circuit for generators: :18 is 's'hown schematic'ally. On

"onthese generators isdesignated'in the schematic "-di agram as generator I whereas the other -gen- 'indicated asgenerator li. These-"gen- 'ratorsi generate electric current which is supplied throu'gh relays -29 and 3ll' -to a load, -indioated at 3 I 'wh ich maybe the starter motor of an aircraft engine to be started.

-A manual control switch- 32- is connected in 'series with a bat'te'ry' 'or 'ot-her-source of low po- -t'ential 33g 'one side of the battery being grounded 32. Whenmanual control -sW-itch 32 is closed, currnt flows from battery 33 through n 'a and- 36 o f relays' '29 and 3ll,respectively. 1 m gizationof these coils-closes switches 37 and." 3B

of 'rel'ay s' 29 and 3U' thereby completing the circuit from generators I- and 1 II', respectively, through Iload ii Lto ground.

-Switch 25 isconnected in series between coil 36 and manual switch 32 S'witch 25 is normally closed -to' complete the circ uit throu gh *holding 'coil 36 when switch "2 is closed. -'Whena-rni 26 of switch-=25iisicngaged by governor arm=-22, it is -forcedopen, that .is, contact 'member 39'- is moved from the phantom line; to the full line position as illustrated: in Figure 3. When thus -held open why I governor: arm=2 2 switch 25 breaks the circuit ofr generator IL and the generator is rendered in- :gifective for producing electricali energy for load I When governor arm 22.: movesvout of engagement withswitch -2 5, contact:member -3 9 returns to its closed position again completing the circuit through coil 36 and restoring the connection betweemgenerator I1 and; load 3 i It isto be noted that generatorI-remains-connected.to load 3| under all conditions of operation, so long as manual switch 32 remains in'its'closed position.

1 Frequently engine generator sets of the type herein: described-must standready forimmediate --;use for long periods of time. *At such times engine I i's kept-in operation. 'It is *desirable' that the engine idle" at afairly low speed and accordingly hell-crank I9 is adjustedto relieve the-tension of spring 2|, thus permitting-governor arm 22'*to #moveavtdy from-switchq Band permitting throttle valve I I to remain in a relatively closed position.

At such times engine I idles at a speed of about 1300 R. P. M.

When an aircraft engine is to be started, a starter motor, which comprises load 3|, is connected in circuit with generators I and II and manual switch 32 is closed to impose the load of the starter motor on the generators. This sudden application of load instantly tends to reduce the speed of engine I. As soon as this reduction in speed occurs, bell-crank I9 is rotated clockwise, tensioning spring 2| and swinging governor arm 22 counterclockwise. Such movement of the governor arm immediately opens throttle valve I I to its extreme wide open position and simultaneously forces switch 25 open. Opening of switch 25 disconnects generator II from load 3| and temporarily reduces the load imposed on the engine I. This reduction of load simultaneous with the opening of throttle valve I I permits engine 1 to accelerate rapidly.

As soon as the engine has accelerated to full speed, about 2200 R. P. M., governor I1 acts to swing governor arm 22 clockwise in opposition to spring 2|, simultaneously partially closing throt- 6 -tle' valv Ihand-permitting switch 25 -to 'close, re-establishing the circuit between'=generator-II and' load -3 l The -'impo"s'itio1r'of the full'load of b'oth generators 'omengin I"aiter 'the-"engine is 5 operating at full speed enables the" engine 7-130 assume the full load without stalling.

Were it'not for' 'theprese'nt inventionj'the-sud- 'den imposition of the 'fullload on engine 'Mvhile r it is" idling- 'atl300 R. P. Ma would cause the en- "i Y gine' to stall since "the load would'betoo great to permit acceleration. One "way of solving this *problem-,-aside fromthe present invention-, wculd be to provide anoversized engine I which would "becapable of accelerating even'under full-load conditions Iio'wever,*this does'notoffer a'practi- "cal solution since" it is desirablefor reasons of cost and weight, to use the smallest engine ipos- "s'ible. I

It-isto be noted thatigovernor arni 22 does 0 -not-engage switch -2 fi 'until throttle valve I I: is in itsextreme full open position. Thus governor I "I -may regulate thepo'sition' of throttle valve l ilover a large" operating .range' without actuation of -=sw'itch 25.' In other 'words,'.under full spe'ed; full 25 load'conditions, governor I I holds throttle valve I I in a position slightly less than full open. It "only when the engine is overloaded that the 'igov- *ernor opens the throttle valveistilliurtherz in-ran attempt to 'maintain engine. speed that arnii22 engages switch 25. Thusithe mechanismro' .the l present invention is also "eifectivei.-for:preventing overloading of the enginefgeneratorset,.for lwhen suchoverloading does occur; switclr25 is engaged and a part ofthe load;;in" other wordsaepart of the generator capacity; is cutouts. Whenpartially relieved? of: load; the. engineicanreattain its full speed, after which full-load isfagain imposed on the engineaslhas'been explained. l" If:the=overload condition is:continued;f..the set will: cycle-abe- 40 tween .partial and full irgenerating :ecap acityiand stalling.willzb'eiprevented.v Cycling will:continue until wthe overload; is removed.

It will be-appreciate'dby :those' skilled inthe art that the-'pre'sent device is very b'eneficial',i-par.ticu- 4 5 larly when applied; to engine generator sets .which must -be heldnin readiness for instantsuse for starting military aircraft. It is :to :be: observed that the presentinvention; althoughrvery simple, is foolproof and effective for preventingover- I loading andstalling of an engine generator set.

When load 3i is removed from the system, as for instance, when the aircraft engine has been started, switch 32 is opened and bell-crank I9 is swung couunterclockwise to relieve the tension of spring 2|. Under such conditions governor I! immediately moves arm 22 clockwise closing throttle valve II and re-establishing idling conditions at about 1300 R. P. M.

Having described a, preferred embodiment of my invention, I claim:

1. In combination with an engine generator set having a plurality of generators driven by an engine, a fuel control means for the engine having a movable member for regulating the flow of fuel to the engine, a governor driven at a speed proportional to engine speed, said governor adjusting the position of the movable member of said fuel control means to maintain a pro-deter- 0 mined speed-load relationship for the engine generator set, an electrical switch actuated by said governor when it moves the movable member to a position of maximum fuel flow, said switch being in circuit with one of the generators, actuation of said switch temporarily rendering the associated generator ineffective for electrical energy.

2. In combination, an Otto engine, a pair of electrical generators driven by said engine, a carburetor for supplying combustible mixture to said engine, an adjustable throttle valve in said carburetor, a governor driven by said engine, said governor being connected to said throttle valve to adjust its position to maintain a pre-determined speed-load relationship for said engine, an electrical switch in circuit with one of the generators, said switch being actuated by said governor when said governor moves said throttle valve to its extreme open position, actuation of said switch temporarily rendering the associated generator incapable of generating electrical energy.

3. In combination in an engine generator set of the type including an internal combustion engine in driving relationship with a plurality of electrical generators which are connected in circuit to deliver electrical energy to a common load, a carburetor for supplying a combustible mixture to the engine, an adjustable throttle valve in said carburetor, a multi-speed governor for adjusting the position. of said throttle valve to hold the engine speed to pre-determined constant values, and an electrical switch in circuit with one of the generators, said switch being producing actuated by said governor when said governor moves said throttle valve to its extreme open position, actuation of said switch temporarily breaking the circuit of one of the generators whereby it is rendered incapable of delivering electrical energy to the load.

4. In combination with an internal combustion engine and a plurality of electrical generators driven by the engine, a carburetor for supplying a combustible mixture to the engine, an adjustable throttle valve in said carburetor, a multispeed governor for adjusting said throttle valve to me-determined positions to hold engine speed at pro-determined constant values, and an electrioal switch actuated by said governor when said throttle valve is opened to its extreme position, actuation of said switch breaking the electrical circuit of one of the generators whereby it is temporarily rendered ineffective for generating current.

5. In combination with an engine and a plurality of electrical generators drivenby the engine, a charge forming means for the engine, an adjustable throttle valve in said charge forming means, an engine driven governor for adjusting said throttle valve to maintain a predetermined speed-load relationship for the engine, and an electrical switch actuated by said governor when said throttle valve is opened by said governor to its extreme position, actuation of said switch breaking the electrical circuit of one of the generators.

6. In combination with an engine and a plurality of electrically controlled loading means driven by the engine, a charge forming means for the engine, an adjustable throttle valve in said charge forming means, a governor for adjusting said throttle Valve to maintain a predetermined speed-load relationship for the engine and an electrical control element in circuit with certain of the plurality of loading means. said control element being actuated by said g0vernor to remove the load of one or more of said loading means when said throttle valve is opened by said governor to its extreme position.

7. In combination with an internal combustion engine and a plurality of loading means driven by the engine, a charge forming means for the engine, an adjustable valve in said charge forming means regulating its output to the engine, valve control linkage for adjusting the position of said valve, and an element controlling the load of certain of said plurality of loading means, said last named element being actuated by said valve control linkage to remove the load of one or more of said loading means controlled by said element when said valve is opened by said linkage to its extreme position.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 970,204 Forsberg et a1 -Sept. 13, 1910 1,766,548 Schnitzer June 24, 1930 1,873,168 Wendt Aug. 23, 1932 1,873,982 Rusterholz 1. Aug. 30, 1932 2,100,076 Gilmore Nov. 23, 1937 2,311,285 Stamm Feb. 16, 1943 2,488,171 Campbell Nov. 15, 1949 2,509,731 Edwards et al May 30, 1950

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