US2930370A - Fuel injection system - Google Patents

Description

March 29, 1960 3 Sheets-Sheet '1 Filed Aug. 16, 1956 TO INDUCTION PASSAG 6 7. 4 0 5 W 27. 0 0 0 Z 4 5 0 n F 5 4/ Z 1 m 2 A A 0 6 p 5 6 5 F P w k v. 4. 4/ ,I III .w/u. 7. m. A 1 Z v I I 2 z w 4 v w. 6 I 6 j n0- r /-5 I 0 I z 622 U 2 E Z n m TO INDUCTION PASSAGE INVENTOR. 5250mm BARFOD ATTORNEY March 29, 1960 F. BARFOD 2,930,370

' FUEL INJECTIEON SYSTEM Filed Aug. 16, 1956 5 Sheets-Sheet 2 126 120 I I 123 I32 I22 @6 [42/ we. I

Z {54 r I m a .4 I52 7Q 0 y /56?% 7/4 M [/5 E 40 Li Z jqo INDUCTION /0Z PASSAGE H0 a 105 I06 n L: TO INDUCTION PASSAGE E? .5 INVENTOR.

FREDERIK BARFOD BY @M/fid-W ATTORNEY ZOZ March 29, 1960 BARFOD 2,930,370

FUEL INJECTION SYSTEM Filed Aug. 16, 1956 3 Sheets-Sheet 3 INDUCTION PASSAGE 534 m 325 TO INDUCTION 500 PASSAGE IN VEN TOR. FREDERIK BARF-OD ATTORNEY United States Patent FUEL INJECTION SYSTEM Frederik Barfod, Detroit, Mich., assignor to Bendix Aviation Corporation, South Bend, Ind., a. corporation of I Delaware Application August 16, 1956, Serial No. 604,483 f v 12 Claims. (Cl. 123-140 This invention relates to a fuel injection system for Other objects and advantages in the present invention will become apparent during the course of the following description, reference being had therein to the accompanying drawings in which:

Figure 1 is a schematic view of a fuel injection system embodying my invention;

Figure 2 is a schematic view showing a modified fuel injection system embodying the present invention;

Figure 3 is a schematic view of a further modification of a fuel injection system embodying the present invention;

Figure 4 is a schematic view of still a further modified form of a fuel injection system embodying the present invention; and Figure 5 is a schematic view of the system shown in Figure 3 with the by-pass eliminated.

Referring now to the drawings and more particularly to Figure 1, there is shown a fuel metering system which meters fuel as a function of certain engine variables such as engine speed and induction passage pressure. Metered fuel is supplied by system 10 to a distributor valve 12 for timed distribution to the induction passage of the engine adjacent each cylinder thereof in the form of individual charges. The quantity of fuel in each charge is determined by the angular velocity of the distributor valve and the position of a control piston or valve 14 mounted for axial movement within the distributor valve. The position of piston 14 is determined by changes in the fuel pressures supplied by system 10 acting on the ends thereof.

Numeral 16 designates a housing having an inlet 18 adapted for connection with a source of fuel (not shown) and with the inlet 29 of a pump 22 which is mounted in the housing on 'a shaft 24. Mounted also on said shaft and coaxial with said pump is hollow cylindrical distributor valve 12 having a port 26 located in the side wall thereof which is adapted for successive registration with a plurality of ports 28 formed in housing 16. Each port 28 is connected to a conduit 30 which terminates 2 trolled by a piston 14 which is responsive to variations in pressures in chambers 38 and 40 which are respectively located on opposite sides of the piston. Fuel under pressure is supplied to chamber 38 from the outlet 42 of pump 22 via conduit 44 and metering restriction 46. Fuel from chamber 38 is in free communication with the interior of valve 12 through bores 48.

Fuel under pressure is supplied to chamber 40 from the outlet 42 of pump 22 via conduit 44, valve 50 and by-pass 52. Valve 50 is subjected to induction passage pressure through passage 54 and is movable in response to changes in said pressure. An adjustable stop member 56 is provided to determine the maximum opening of valve 50 and thereby, as will be explained later, the idling fuel supply to the engine. The flow through bypass 52 is controlled by a piston 58 which is urged by spring 60 toward open position. Chamber 40 is connected to inlet 18 by means of restricted conduit 61.

A plunger 62 located in a compartment 64 formed in 'housing 16 is connected to the induction passage through conduit 66and is movable in response to a predetermined induction passage pressure to engage piston 14 and to move it to a position to close port 26 and thereby cut off flow of fuel to the engine.

In the operation of the fuel injection system shown in Figure 1 fuel is delivered from a source at substantially constant pressure to the pump 22 the output of which varies as a function of engine speed. Chamber 38 contains fuel under pressure which varies as 'a function of engine speed and which urges piston 14 in the direction to 'open port 26. Chamber 40 contains fuel under pressure which varies as a function of engine speed and induction passage pressure and which urges piston 14 in the direction to close port 26. Piston 14 moves to establish a balance of pressures between chambers 38 and 40. With each change of speed and/or induction passage pressure a pressure differential pressure may exist momentarily between chambers 38 and 40 which will cause the piston 14 to seek a new position whereby the pressures will be equalized. The piston 14 is relatively small in size and hasa relatively small moment of inertia so that it may respond quickly to changes in pressure. Piston 14 is adapted for axial movement relative to the rotary valve 12 so that it will be subjected to relatively little wear whereby leakage around the piston or sticking of the piston is substantially eliminated.

The plunger 62 is provided to cut off the supply of fuel for the engine during conditions of deceleration when the vehicle is driving the engine. f.

In order to insure a supply of idling fuel to the engin adjustable stop member 56 is provided to control the maximum opening of valve 50 so as to prevent an excessive quantity -of fuel from being by-passed around the metering restriction 46 through chamber 40 and conduit 61 to the inlet. I

As notedipreviously, the output of pump 22-varies directly with engine speed. For many engines such an in a nozzle 32. Nozzles 32 are adapted for insertion in the induction passage of the engine adjacent the inlet valve of each cylinder thereof or in some installations the nozzles may be placed in the induction passage in such a manner that one nozzle may supply two or more cylinders. It is to be understood that in other installations the nozzles could be located in the cylinder walls of the engine. Each of the nozzles is provided with a valve 34 which is urged towards closed position by a p i Shaft 24 is adapted to be driven as a function of engine speed so that valve port 26; registers with successive ports 28 in timed relation to engine operation. The

quantity oftuel flowing through valveport 26 is conoutput would .be in excess of engine requirements. To compensate for different engine requirements a by-pass 52 may be provided wherein a quantity of fuel, the.

amount of which is determined by spring 60 is by-passed around the pump. In some installations, however,'by-

pass 52 .may b e omitted. e In the embodimentshown in Figure 2;'numeral10.0

designates a housing having an inlet 102 which ,is con; I

supply fuel.

.sha'ft is a hollow cylindrical distributor valve .120 'having .a port 122 located :in the .side wall thereof which isadapted for successiveregistration with aplurality of ports 124 formedin housing 100. The number of ports 124 may conveniently conform to the numberoftcylinders in the internal combustion engine ,to which the fuel injection system of the present invention is adapted .to Each port -124 is connected to a discharge conduit 126 having a nozzle 128 secured to one end thereof. Each nozzleis provided with a valvegl30 which .is.urged towards closed .position .by spring 132.

A piston 134 isxrnounted in valve 120 fortaxialmove- :menttherein and is adapted to enact with port 122 ;to :controlthe flow therethrough. A spring 136 is located to urge piston 134 in a direction to close port 120. Piston 134 is subjected on opposite ends :to the fuel pressures existing in chambers 138 and 140 respectively.

Fuel is supplied to chamber 138 from pump 114 via conduit 142 and meteringrestriction 144. Fuel is supplied to chamber 140 via conduit 142, valve 146, port 148 and -by-pass 150. Free access to the interior .to valve 120 for fuel in chamber 140 is provided by bores 152 formed in a reduced portion of valve .120. Valve 146 is constructed similar to the previously described valve 50 of the embodiment shown in Figure 1 and operates to regulate the flow of fuel to chamber 140 as a function of changes in induction passage pressure. A pressure responsive valve 154 is located in the housing to coact with port 148 to equalize the pressure drop across metering restriction 144 and valve 146. Chamber 140 is connected to the inlet 102 by means of conduits 156, 116 and 157 through parallel arranged- check valves 158 and 160.

In the operation of the embodiment of Figure 2 fuel received from the source is boosted in pressure by pump 106 and delivered to pump 114 where the fuel is discharged as a function of engine speed into conduit 142 for transimssion through parallel paths containingimetering restriction 144 and valve 146 to chambers 138 and 140 respectively. Upon starting of the-.engine'the fuel control piston 134, under the influence of spring 1136, is in a position to close off port 122. Check valves,158 and 160 are closed however and cause the pressure to build up rapidly in chambers 138 and 140. When the pressure is raised to a predetermined amount 'which is sufficient to open nozzle valve 130, check valve .158 .is opened permitting fuel to flow from the chamber 140 via conduit 156 to inlet 102. During normal operation piston 134 will seek an equilibrium position wherein the fuel pressure in 138 is balanced by the fuel pressure in chamber 140 plus the forceof spring 136. Upon changes in speed orinduction passage pressures a momentary change of pressure may occur in chambers :138 and/or 5140.3.Ild cause the piston to seek a new equilibrium position. The spring 136 creates a substantiallyconstant pressure differential between the pressures in chambers 138 and 140. This pressure differential will-exist across the bypass 150 and thus causes a substantially constant quantity of fuel to be by-passed therethrough. This by pass is provided to accommodate for the operation characteristics of certain engines-and may in some instances be omitted. If the by-pass 150 is omitted then too is the spring 136 omitted.

Check valve 160 is provided as a safety valve to prevent excessive pressures from beingbuilt up within the system.

In the embodiment shown in Figure3 numeral 200 "designates a housing'having an inlet 202 which is adapt- "ed =to be connected =to "a source of fuel (not shown) 'through'an-appropriate conduit. A pump 204 ismounted inthe'housing forconnection with the inlet 202. Appropriate means (not shown) may be provided to rotate pump .204 as ,ajunction of engine speed. .Also mounted in said housing is a distributor valve 206 adapted to be rotated as a function of engine speed by appropriate means (not shown). Valve 206 is provided with a port 208 located in the side wall thereof which is arranged for successive registration with a plurality of ports 210 formed in the housing 200. The number of ports 210 may conveniently correspond to the number of cylindersin the engine with which the fuel injection system is associated. Each port 210 opens into a discharge con duit 212 having a nozzle 214 secured to one end thereof. The number of discharge conduits may be equal to or less than the number of cylinders of the engine depending on the construction of the intake manifold. The flow through port 203 is controlled by a piston 216 which is mounted for axial movement within valve 206. Piston 216 is responsive to differences in pressure between the pressures in chambers 218 and 220 located respectively on opposite sides of said-piston. Fuel is supplied to chamber 218 from pump 204 via conduit 222 and me- .tering restriction 224. Fuel is supplied to chamber220 from pump 204 via conduit 222 and valve 226. Valve 226 is identical to valve 50 described above in connection with the embodiment shown in Figure 1. Chamber 220 is connected to inlet 202 via conduit 228 and restriction 230. Chamber 218 is also connected to inlet 202 via conduit 232 and restriction 234. A spring loaded piston 235 formed with a port in one end is located in conduit 232 to control the flow through restriction 234.

In operation, fuel is supplied at substantially constant pressure to inlet 202 from whence it flows to pump 204 where the pressure is increased as a function of engine speed. .The pressure of fuel in chamber 218 varies as a function of engine speed and acts against an end face of piston 216 to urge such piston in a direction to increase the fuel flow through port 208. The pressure of fuel in chamber 220 varies as a function of engine speed and induction passage pressure and acts against an opposite end face of piston 216 to urge said piston in a direction to decrease fuel flow through port 208. Piston 216 seeks a position to balance the pressures in chambers 218 and 220 and is movable in response to momentary changes in the pressure in either chamber which may be caused by changes in engine speed or induction passage pressure. A conduit232 provides for a substantially constant by-pass of metered fuel from chamber 218 to adapt the fuel injection system to the operating characteristics of certain engines. In some engines as previously noted such a by-pass system may be omitted, as shown in Figure 5 wherein similar numerals have been used to designate similar parts.

In the embodiment shown in Figure 4 there is pro vided means for enrichment of the fuel air mixture ratio during starting and means for cutting off the fuel during conditions of deceleration when the vehicle is driving the engine. In this embodiment numeral 300 designates a housing having an inlet 302 which is adapted to be connected with a source of fuel at substantially constant pressure (not shown) through an appropriate conduit. Inlet 302 is connected to boost pump 304 by means of conduit 306. Pump 304 increases the pressure of fuel supply from inlet 302 and discharges to a main pump 308 through a conduit 310. Pumps 304 and 308 are mounted in housings 300 on a common drive shaft 312'which is adapted to be driven as a function of engine speed by appropriate means (not shown). Also mounted on said shaft is a hollow cylindrical distributor valve 314 having a port 316 formed in a side wall thereof. Port 316 is constructed and arranged for consecutive registration with a plurality of discharge conduits 318 which radiate from housing 300. Each conduit 318 is provided 'at-one'end With'a nozzle 320 whichis adapted for 'ins ertion in the induction passage or cylinder-wall of-the-engine to which the fuel injection system is adapted to supply fuel. 'The fiow of 'fuel through port 316 is controlled by a piston 322 which is mounted for-an axial movement within valve 314. Piston 322 is subjected on opposite ends to the pressures in chambers 324 and 326 respectively and is responsive to any pressure differential that may exist therebetween. Fuel is supplied to chamber 324 from main pump 308 via conduit 328 and metering restriction 330. Fuel is supplied to chamber 326 from pump 308 via conduit 328, valve 332 and by-pass 334. Valve 3323 is adapted for connection to the induction passage of the engine through passage 336 and is movable in response to changes in pressures therein. By-pass 334 is controlled by a spring loaded piston 338 which is arranged to provide for the by-passing of a substantially constant quantity of fuel. Chamber 326 is in free communication with the interior of valve 314 through a plurality of bores 340 formed in the side wall of the valve. Chamber 326 is connected to inlet 302 via conduits 342 and 310 and parallel flow paths 344 and 346 which are controlled by check valves 348 and 350 respectively. Restricted fiow path 344 is designed to constitute the normal connection for conduit 342 to the inlet 302. Check valve 348 is provided to insure therapid build up of pressure to a value sufiicient to open the valves in nozzles 320. When the pressure has risen to that value, check valve 348 opens and remains open during the remainder of the operation of the system. Check valve 350 is adapted to open only if the pressure housing 300 exceeds a predetermined maximum pressure.

Starting enrichment may be provided by a solenoid actuated plunger 352 which is adapted to be energized when the starting switch 354 is closed. When energized, plunger 352 moves downwardly to engage piston 322 to move it in a direction to open port 316.

Degassing or fuel cut-off during certain conditions of deceleration may be provided by solenoid actuated valve 356 which is adapted for actuation either by manual switch 358 or induction passage pressure responsive switch 360. Upon energization valve 356 moves to close metering restriction 330 causing the pressure in chamber 324 to be reduced whereby piston 322 will be moved rapidly to a position to cut-off port 316 by the pressure of fuel in chamber 326.

It is essential for good engine operation that the discharge from the rotary distributor valve reflect quickly and accurately changes in the fuel metering system.

In the past where fuel distribution and fuel control have been attempted by a single rotatable valve which-is also movable axially many difiiculties have been experienced. The first major difficulty has been in obtaining the accurate location of a plurality of discharge ports relative to the valve so that with the valve in any given axial position successive registration of the valve with the discharge ports would result in equal distribution of the fuel. The second major difiiculty of a single distributor valve has been in its slowness to respond to the changes in fuel metering pressure. This slowness is due in part to friction and in part to a relatively large moment of inertia. The frictional drag on such a valve may also havean effect on accuracy of distribution as well as on response. Because of the poor lubricating medium, fuel, in which the valve operates and because of the valves high rotational speed with respect to the side walls of the housing frictional drag mayincrease to the point that the valve will stick.

These past difficulties have been substantially overcome by the provision of a rotary distributor valve having a single port which is adapted for registration with a plurality of substantially larger discharge ports or conduits; and by the provision of a relatively small control piston adapted for axial movement within the valve to control the flow through. the single valve port. The problem of accuracy of location of a plurality of ports is eliminated. Only the single valve port need' be accurately sized. The discharge ports may be substantially larger than the single valve port so as to accommodate for inaccuracies and still permit the singleto register therewith. The problem of control valve sticking and slowness of response is substantially reduced or eliminated. The reduction in size of the control piston correspondingly reduces the moment of inertia; The location of the control piston so as to be subject only to relative axial movement reduces wear and frictional drag. While I have described my invention in its preferred form it will be understood by those skilled in the art that changes in constructions from that disclosed may be made without departing from the underlying principles of the invention.

I claim: a 1. In a fuel injection system for a multi-cylinder internal combustion engine having an induction passage and a source of fuel, a housing, means connecting said housing to said source, a plurality of conduits adapted to connect said housing with said passage, a rotary valve in said housing, a port in said valve adapted for suc.- cessive registration with said conduits,.and a fluid pres: sure responsive piston reciprocably mounted in said valve and formed'to control the flow through said port, said piston being subjected on one side to a fluid pressure which varies as a'fu'nction of engine speed and induction passage pressure and on the other side to a pressure which varies as a function of engine speed. 2. In a fuel injection system for a multi-cylinder in!- ternal combustion engine having an induction passage and a source of fuel, a housing, a plurality ofports in said housing, a rotary valve in said housing, a port in said valve adapted to register with said first mentioned ports, a piston reciprocable in said valve to controlthe flow through the port therein, a pump, an inlet and an outlet for said pump, a passage adapted to connect said source to the inlet of said pump, a conduit adapted-to connect the outlet of said pump to said housing on one side of said piston, a second conduit adapted to connect said outlet to the housing on the other side of said pis. ton, a metering restriction in one of said conduits, an induction passage pressure responsive valve in the other of said conduits, and means for equalizing the pressure drop across said restriction and pressure responsive valve. w

3. In a fuel injection system for a multi-cylin'der internal combustion engine having an induction passage and a source of fuel, a housing, a plurality of conduits adapted to connect said housing withsaid passage, a passageway connecting said source with said housing, a rotary valve in said housing, a port in said valve adapted to successively connect said passageway to said conduits, a metering restriction in said passageway, an engine driven pump in said, passageway adapted to supply fuel to said restriction at a pressure varying'as afunction of engine speed, a conduit connected to said pasa sageway between said restriction and said pump and to said passageway anterior said pump, an induction passage pressure responsive valve in said last-mentioned conduit, a piston in said rotary valveresponsive to a pressure.

differential between fuel pressure in said last mentioned conduit and fuel pressure in said passageway posterior.

ber in said housing on the other side of said valve, a

conduit connecting said first chamber with saidsource,

a metering restriction in said conduit, a passage connect ing said second chamber to said conduitanterion-said restriction, a valve in said passage, responsive-tea pressure varying as a function of inductijon" ,passagerpres'sure,

a pump in said conduit for supplying fuel to said restriction at a pressure varying as a functionof engine 7 speed, means for equalizing the pressure in said first and second chambers, a port in said rotary valve, a piston in said rotary valve responsive to a differential in pressure between said first and second chambers for controlling the flow through said port.

5. In a fuel injection system for a multi-cylinder internal combustion engine having an induction passage and a source of fuel, a fuel conduit for each of said cylinders, a passage connected to said source, a rotary valve, a port in said valve adapted to successively connect said passage with said conduits, a fuel pressure responsive piston in said valve controlling the flow through said port, and means responsive to a predetermined induction passage pressure for moving said piston to close said-port.

6. In a fuel injection system for a multi-cylinder internal combustion engine having an induction passage and a source of fuel, a fuel conduit for each of said cylinders, a passage connected to said source, a rotary valve, a port in said valve adapted to successively connect said conduit to said passage, a piston in said valve adapted to control the fiow through said port, said piston being subjected on one side to a fuel pressure which tends to move the piston to open said port and on the other side to a fuel pressure which tends to close said port, and means responsive to a predetermined induction passage pressure for reducing the pressure on said one side to a value lower than the pressure on the other side whereby said piston is moved to close said port.

7. "In a fuel injection system for a multi-cylinder internal combustion engine having an induction passage and a source of fuel, a plurality of discharge nozzles, a valve in each of said nozzles, resilient means urging said valves toward closed position, a passage connected to said source, a conduit connected to each of said nozzles, a rotary valve having a port therein adapted to sucessively connect said conduits to said passage, a metering restriction in said passage, an engine driven pump in said passage upstream of said restriction, a passageway connected to said passage on either side of said pump, a valve in said passageway responsive to variations in induction passage pressure, a piston in said rotary valve responsive to a differential in pressure between the pres sure in said passage downstream of said metering restriction and the pressure in said passageway for controlling the flow of fuel through said port to said conduits.

8. In a fuel injection system for a multi-cylinder internal combustion engine having an induction passage and a source of fuel, a plurality of discharge nozzles, a valve in each of said nozzles, resilient means urging said valves toward closed position, conduit means adapted to connectsaid source to said nozzles, a metering restriction in said conduit means, an engine driven pump in said conduit means upstream of said restriction, a passage connected to said conduit means on either side of said pump, a valve in said passage responsive to variations in induction passage pressure, a valve in said passage openable in response to a predetermined fuel pressure-acting thereon, resilient means urging said last mentioned valve toward closed position and a valve in said conduit means downstream of said metering restriction responsive to the differential pressure between the pressure in said conduit means downstream of said metering restriction and the pressure in said passage downstream of said induction pressure responsive valve for controlling the fiow of fuel to said nozzles.

9."In a 'fuel injection system for a'multi-cylinder internal combustion engine having an induction'passage and "a source of fuel, a plurality of discharge nozzles, a valve in each of said nozzles, resilient means urging said ,va'lve's toward closed position, conduit means adapted to connect 'said source to said nozzles, a metering restric- =tion insaid 'conduit'means, an engine driven pump in said conduit means upstream of said restriction, a passage connected to said conduit means on either side of said pump, parallel flow paths in said passage, a valve in said passage upstream of said flow paths responsive to variations in induction passage pressure, a valve in one of said paths openable in response to a first predetermined fuel pressure, a valve in the other of said paths openable in response to a second greater predetermined fuel pressure, and a valve in said conduit means downstream of said restriction responsive to the differential between the pressure in said conduit means downstream of said restriction and the pressure in said passage downstream of said induction passage pressure responsive valve.

10. A fuel injection system for an internal combustion engine having an induction passage and a source of fuel comprising a conduit adapted to connect said source to the engine, a metering restriction in said conduit, a pump in said conduit upstream of said restriction for supplying fuel to said restriction at a pressure varying as a function of engine speed, a passageway connected to said conduit on either side of said pump, an induction passage pressure responsive valve in said passageway, a by-pass connecting said conduit downstream of said restriction to said conduit upstream of said pump, a piston in said by-pass responsive to the differential between the pressure in said conduit downstream of said restriction and the pressure in said conduit upstream of said pump, and resilient means urging said piston in a direc tion to increase fuel-flow through the by-pass.

11. In a fuel injection system for an internal combustion engine having a starting motor circuit and a source of fuel, a plurality of discharge nozzles, a conduit connected to said source of fuel, a rotary valve in said conduit, a port in said valve adapted to successively connect said nozzles to said port, pressure responsive means in said valve adapted to control the flow through said port, and means energizable by said starting motor circuit to move said first mentioned means in a direction to increase flow through said port.

12. In a fuel injection system for a multi-cylinder in ternal combustion engine having a source of fuel, a plurality of discharge nozzles for said engine, a housing having a plurality of coplanar circumferentially spaced ports formed therein, means connecting said ports to a respective nozzle, 21 valve rotatably mounted in said housing and formed with an axial cylinder therein, a radially extending conduit in the sidewall of said valve connecting said cylinder with the peripheral surface of said valve, said conduit being adapted for successive registration with said ports, conduit means adapted to connect said source of fuel to said valve cylinder, means in said conduit means for metering the fuel therein, and a piston mounted in said valve cylinder and movable in response to variations in metered fuelpressure for variable registration with said conduit to control the effective area thereof whereby the quantity of fuel delivered to a nozzle is regulated as a function of the angular velocity of said valve, the area of said conduit and metered fuel pressure.

References Cited in the file of this patent UNITED STATES PATENTS 2,145,379 Vogelei et a1. Jan. 31,1939

2,210,067 Cummins Aug. 6, 1940 2,516,147 Robinson July 25, 1950 2,667,840 I-Iigh Feb. 2, 1954 ,673,556 l1eggio Mar. 30, 1954 FOREIGN PATENTS 616,721 Great Britain Jan. 26, 1949

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