US2771068A - Starter-controlled fuel supply for internal combustion engine - Google Patents

Description

Nav. 20, 1956 P. F. JETTINGHOFF 2,771,058

STARTER-CONTROLLED FUEL SUPPLY EUR INTERNAL CM-BUSTION ENGINES Filed March 27, 1953 @gli United States Patent STARTER-CGNTROLLED FUEL SUPPLY FOR INTERNAL COMBUSTION ENGINE Paul F. Jettinghoff, Grosse Pointe Woods, Mich., assgnor to International Harvester Company, a corporation of New Jersey Application March 27,1953, Serial No. 345,114

4 Claims. (Cl. 123-179) This invention relates to internal combustion engines, and more particularly to a safety control system for use in conjunction with the fuel supply system of an nternal combustion engine.

The utilization of liquefied petroleum gas, such as propane, as a fuel for operating internal combustion engines has become popular of recent date. The popularity of liquefied petroleum gas, commonly referred to as LPG, as a fuel is due largely to the fact that its use affords the LPG engine operator certain economical and functional advantages over the engine operator who employs conventional fuel such as gasoline or diesel oil. However, on the other hand, many more safety precautions must be taken to avoid the creation of dangerons situations which result when the fuel is improperly used since it is highly volatile and, unlike gasoline or diesel fuel oil, it must be stored under pressure before being admitted to the engine.

Inasmuch as LPG is confined in the fuel supp1y tank under pressure a solenoid-actuated valve, normally closed under yieldable spring means, is generally interposed in the fuel supply line leading from the fuel tank to the engine as a safety measure. The solenoid is usually energized to open the valve when the ignition circuit system is energized just prior to starting the engine and the valve is held open as long as the ignition circuit system is energized. Obviously, the fuel supply tank is in communication with the engine, if the ignition circuit is energized, even though the engine is not actually running and consuming fuel as when the engine inadvertently stalls. It is apparent that if such 4a condition is allowed to exist for any length of time, LPG, being under pressure, will escape from the engine and accumulate under or about the engine covering or in the vicinity of the engine and mix with air to form a potentially dangerous explosive mixture. Heretofore, it was necessary to deenergize the ignition circuit system to close the fuel supply valve whenever the engine was left unattended to avoid the possibility of the engine accidently stalling when the ignition circuit system was still energized and permit an explosive mixture to accumulate exteriorly of the engine. It is, therefore, the primary objective of the present invention to provide a safety control system for an internal combustion engine for controlling the fuel supply line thereof whereby the fuel supply is positively cut off when the engine is stopped even though the ignition circuit system is energized.

Another objective of the invention is to provide a safety control system for an internal combustion engine of the type having a valve for controlling the ow of fuel to the engine and in which the control valve is influenced by the setting of the ignition circuit switch and the uid pressure developed by the lubricating oil system of the engine.

A further object of the invention is to correlate the uid pressure developed by the lubricating oil system of an engine and the fuel supply system whereby fail- 2 ure of uid pressure in the lubricating oil system will automatically result in the stoppage of fuel ow to the engine.

A still further object is to operatively interconnect the ignition circuit, starting circuit, and lubricating oil system of an internal combustion engine to control the operation of a fuel supply valve.

A still further object is to provide a control system for regulating a fuel supply valve in an internal combustion engine whereby the valve, which is urged to its closed position by yieldable spring means, is initially opened by energization of the engine ignition and starter circuits and is maintained in its open position by means responsive to a condition necessary to the continued proper operation of the engine even though the starter circuit is thereafter deenergized.

The foregoing and other important objects and desirable features inherent in and encompassed by the invention, together with many of the purposes and uses thereof, will become readily apparent from a reading of the ensuing description in conjunction with the annexed drawing, which is a schematic view of the safety control system forming the invention.

Referring to the drawing in detail, an intern-al combustion engine cylinder block 10 is partially shown. A crankcase oil sump 11 is attached to the bottom face of the cylinder block 10. In order to better illustrate the invention, the crankcase oilsump 11 is partially cut away to reveal a conventional oil pump 12 which forms a part of the engine forced feed lubricating oil system. The oil pump 12 is driven by rotation of the engine crankshaft (not shown) and is adapted to receive oil from the sump 11 and circulate the oil, under pressure, throughout the engine. l

The engine crankshaft is `initially `rotated to start the engine by means of a starting motor 13 operatively connected to the crankshaft through the intermediary of a solenoid-controlled pinion gear 14 and a ring gear 15 which is fixed to the crankshaft and meshable with the pinion gear. The starting motor 13 is controlled by a manually operated switch 16 disposed in the engine starting circuit, designated generally by numeral 17. The engine starting circuit 17 includes'a wire or conductor `18 electrically interconnecting one terminal of a source of electrical energy, such as a storage battery 19, and ground. One side of an ignition switch 20 is electrically connected to the other terminal of the storage battery 19 by a conductor 21. A conductor 22 interconnects the opposite side of the ignition switch 20vto a terminal of the starter switch 16 and a conductor 23 leads from the opposite side of the starter switch to one end 24 of a solenoid winding 25, the purpose of which will be explained hereinafter; rThe opposite end 26 of the solenoid winding 25 is grounded by means of a conductor 27 to complete the engine starting circuit 17. From the foregoing, it is obvious that in order to start the engine it is necessary to close the ignition switch 20 and manually actuate the starter switch 16 to its closed position to supply electric current to the starting motor 13. While the ignition switch 20 is shown in series with the starter switch 16 and the storage battery 19, it is to be understood that the ignition switch could be bypassed by electrically connecting one terminal of the starter switch directly to the storage battery Without departing from the spirit and scope of the invention.

Fuel for operating the engine is stored in a fuel supply tank 28 and is directed to the engine through pipe 29, valve 30, and pipe 31. Thel valve 30 includes a hollow body 32, which is in liquid communication with the pipes 29 and 31, and a reciprocable plunger 33. A helicallywound compression spring 34, encircling the plunger 33,

yiellably lll'geS anenlarged valve element 35 provided on Q99. @1.111.4 Qf. iplllllger utoengagement withavalve seat 36 formed on the valve body 32 for preventing fuel from entering the valve body from the pipe 29 and thus stop- Ellis lllslQWQf fuel; through pipe 31. to. the engine- The ERP?? @e431 f the plunger 33, as viewed. in thefdrewins. is slidable within the central bore 38 of -a spool 39, which supports Vthe solenoid winding or coil 2 5, 'and is drawn guardia-easiest the resilient action ofthe spring 3.4. by the fopce developed by the solenoid when the winding 25 is energized. Movement of the plunger 33 upwardly talesthe valve element 35 from the. valve seat 36 to establish liquid communication between the fuel tank 28 andthe engine. Upon deenergization of the winding 25, the Valve element is forced intoengagement with the YlYG. Seat 36 by the spring 34 to thusquiclcly and positively 'stop theftlow of fuel to the engine. It will be obvious 'that fuel is permitted tollow. from the supply t a r,1l t"2`8l O the engine when the ignition switch 20. is closed and the starter switch 16 is actuatedv to energize the starting motor 13. l

In order to maintain the plunger 3.3.in its raised, valveopen. position independently of the electrical condition of the engine. starting circuit 17, a pressure responsive switch 4 0 *isI provided whichv includes an open-ended cylindrical housing 41 closed at one end by an enlarged cover 42. The 'cover 42 includes upper and lower dome shaped sections 4 3, 44 having a diaphragm 45 clamped therebetween whereby the chamber 46v defined by the upper section, 43 land the diaphragm 45 is pressure-sealed from the housing 41. A spring support 47 is threaded into the end of the housing 41 opposite the cover 42 and is adaptedy to seat one end of a helical wound, compression spring 48. The other end of the spring 48 abuts the underside of the lower `disc 49 of a pair: of discs 50 suitablyfastened to opposite sides of the central portion of the diaphragm 45. A binding post 51, supported by .and electrically insulated from the housing 41, carries a vertically extending conductor 52 provided with a contact element 53. Secured to thelower section 44, in the same manner as binding post 51 is secured to the housing 41, is a binding post 54. A spring-like conductor S, has one end fastenedto the binding post 54 `and its opposite end provided with a contact element56 disposed in vertical alignment with the contact element 53 and the peripheral edge of the lower disc 49. Leading from the pressure side of. the oil pump 12 is 'a conduit or pipe 57 which is connected to the upper section 43 of the cover 42 for establishing liquid communication between the oil pump and the chamber 46. lt will be appreciated that upon the reception of oil in the chamber 46 having a pressure sufficient to.. compress the spring 48 the lower disc 49 is` caused to force the Contact element S6V into abutting engagcment with the contact element 53 for completing an electricalcircuit to be described hereinafter. Conversely, upon. release of fluid pressure in the chamber 46 the spring 48 movesl the disc 49 upwardly and allows the contact element 56. to separate from the contact element 53to,break the circuit.

A conductor 58 electrically interconnects the binding post S1 and; the conductor 23 and a conductor 59 leads from. the binding post 54 to the conductor 22. A branch conductor-.is electrically connected to the conductor 59 for supplying current to the. engine ignitionsystern.

In, operation, the safety control system functions as follows: The operator first closes the ignition switch 2i). Thereafter, the starter switch 16 is actuated to its closed position. causing the starting motor 13 to rotate the crankshaftrand drive the oil pump 12 and simultaneously causing the valve element 35 to be raisedfromits mating valve seat 36 to permit the flow of fuel to the engine from the fuel tank 28. Within-a timeinterval of two or three seconds the engine begins to re andthe engine starter;switchk1;6..is released. 4The oilpump ,12, which is drivenbyrotation-Qfthe engine crankshaft, delivers oil under pressure to the engine lubrication 'system as well as.t .tl1.e..e1.1e 1nber46... Ille. spring .48..whichresistsmoxement of the lower disc 49 downwardly, as viewed in the drawing, is designed to maintain the contact elements 53 and 56 separated until the fluid pressure developed by the oil pump 12 is equal to or exceeds the normal oil pressure developed when thecngine is idling which is approigimately 9 pounds per square inch.V The` normal oil pressure at idling speed is .reached during the. time interval the engine starter switch 16 is closed so 'that the solenoid windingk 25. remainse energized by means; of, current flow through the pressure responsive. switch 4l).` even though the engine starter switch 16 is moved to its open position. The fuel control valve element 35. is heldin its open position as long as the engine is operating in a normal manner.l Howeven. if the` .engine should inadvertently stall the fuel supply to the engine will be quickly and positively cut off since the oil pressure developed by the oil pump, 12 will fall below-the-normal pressure ydevelunedv et idling speed; ellewinathe Contact elements l53. and;

56e te Seperate and break the electrical circuit te. the

solenoid windingV 25. Thel embodiment of the inventionlchosen for. the pur Poses Qf illustrativa and deseptien herein is that pre-f ferred as the 'resultr of'selective tests based upon requirementsfor achieving the objects of the invention and dcveloping the ,utility thereof in the I nost desirable manner,I due regardl being had to existing` factors of economy, simplicity of design. and construction, and the improvements sought to` be effected. It will be appreciated, therefore,l that thelparticular structural and function aspects emphasized hereinV are not intended to exclude, but rather to suggest, such other adaptations and modifications of the inyention as fall within the spirit and scope of the inven. tien es dened in. 'theerpended Claims- What is claimed is:

l A; safety control system. for an internal combustion engine having' a's'ource. of fuel normally suppliedl under pressure, ai fuel supply conduit and au engine-operated pressurelubricating oil system; a valve in said conduit for controlling thel supply of fuel to said engine, said valve, being. biasedr to its closedcondition; a solenoid cooperablefwit-h said, valve, said solenoid beingeiective when energized, to open said valve against the force of scid bias;y a source of electrical energy; an electrical cir,- cuitxinterconnecting said, solenoid and said source of electrical energy; an engine starter switch in said circuit', an ignition switch in said circuit in series with said starter` swith, Said, circuit being completed tocnergize said solenoid when said: switches are in their closed con-v ditions; pressure responsive switchv operatively, connected to Asaid pressure lubricating oil system and being actuatable to its closed condition upon the attainment of a predetermined fluid pressure in saidr engine-operated pressure lubricating oilsystem; a. conductor leading from one side ofV said'pressureu responsive switch tosaid` sole-Ay noid; and av second conductor leadingfrom the otherv side of said pressure responsive switch to said electrical circuit at a point between said starter switch and said ignition switch.

2. A safety control system for an internal combustion enginehavinga source of lfuel normally supplied under pressure, a fuel supply conduit and a pressure lubricating oil system, a, valve in said conduit for, controlling the supply of fuel to said engine, said valve being biased to its closed condition; a solenoid cooperable with said valve, said solenoid 'being effective when energized to open said valve against the force of said bias; manually controlledA electrical means for initially energizingl said solenoid including aflirst electrical circuit operatively connected to asource of electrical energy and saidsolenoid, and an ignition switch and an engine starter switch located insaidwcircuit inpseries, said circuit being completed toenergize said. solenoid when said switches are,in their Closed! @minions and Seefeld eleetrieet means; fer main:

taining said solenoid energized independently of the condition of said starter switch including a pressure responsive switch electrically connected in parallel with said starter switch and in series with said ignition switch and said solenoid, said pressure responsive switch being operatively connected to said pressure lubrication oil system and being actuatable to its closed condition upon the attainment of a predetermined tluid pressure in said pressure lubricating oil system.

3. A safety control system for an internal combustion engine of the type described having a source of fuel normally supplied under pressure, a fuel supply conduit and a pressure lubricating oil system; a valve in said conduit for controlling the supply of fuel to said engine, said valve being biased to its closed condition; electrically operable means cooperable with said valve, said electrically operable means being eiective when energized to open said valve against the force of said bias; means for initially opening said valve including a first electrical circuit operatively connected to a source of electrical energy and said electrically operable means, and an ignition switch and an engine starter switch located in said circuit in series, said circuit being completed to energize said electrically operable means when said switches are in their closed conditions; and second means for maintaining said electrically operable means energized independently of the condition of said starter switch including a second electrical circuit connected to said rst electrical circuit and shunting said starter switch and a pressure responsive switch located in said second electrical circuit and operatively connected to said pressure lubricating oil system, said pressure responsive switch being actuatable to its closed condition to complete said second electrical circuit upon the attainment of a predetermined uid pressure in said pressure lubricating oil system.

4. A safety control system for an internal combustion engine of the type described having a source of fuel normally supplied under pressure, a fuel supply conduit and a pressure lubricating oil system; a valve in said. conduit for controlling the supply of fuel to said engine, said valve being biased to its closed condition; electrically operable means cooperable with said valve, said electrically operable means being eifective when energized to open said valve against the force of said bias; manually controlled electrical means for initially opening said valve including a irst electrical circuit operatively connected to a source of electrical energy and said electrically operable means, and an ignition switch and an engine starter switch located in said circuit, said circuit being completed to energize said electrically operable means when said switches are in their closed conditions; and second electrical means for maintaining said electrically operable means energized independently of the condition of said starter switch including a pressure responsive switch electrically connected in parallel with said starter switch and in series with said ignition switch and said valve, said pressure responsive switch being operatively connected to said pressure lubricating oil system and being actuatable to its closed condition upon the attainment of a predetermined fluid pressure in said pressure lubricating oil system.

References Cited in the le of this patent UNITED STATES PATENTS 1,473,303 Lightford Nov. 6, 1923 2,022,725 Lazarus et al Dec. 3, 1935 2,210,044 Schirokauer Aug. 6, 1940 2,370,249 Korte et al. Feb. 27, 1945 2,469,942 Armstrong et al May l0, 1949 2,504,670 Everest Apr. 18, 1950 2,565,984 Newman et al Aug. 28, 1951

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