US2516691A - Fuel injection system - Google Patents

Description

July 25, 195o L. o. FRENcH 2,516,691

FUEL INJECTION SYSTEM y Filed sept., 2s, 194e j f 3a l v Y 1 s .i f 2f Patented July 25, 1950 vUNITED STATES PATENT ori-'ics rom. INJECTION srsram Lena o. French, Milwaukee, wa. Appunti@ septembezs, me, serai N. scesa: 1 calms. (c1. 12s-1w The invention relates to fuel injection systems for internal combustion engines.

` In fuel injection systems now in use using either unit injectors or separate pumps and separate injectors the metering control mechanism has to be duplicated for each unit injector or separate pump unit, so that the parts of the injector system multiply rapidly with an increase of engine cylinders. Furthermore, the arrangement of the controls for radial engines such as aircraft engines becomes complicated where unit injectors are used. Also in those systems in which a single metering pump is used-with a distributor and high pressure pipe lis :ffii separate injectors, the metering pump and the distributor have to work at high pressres with consequent disadvantages. One object of the present invention is to provide a fuel injection system for multi-cylinder internal `combustion engines in which the metering of the fuel for a plurality of pumps or unit injectors is controlled by a metering device common to all the pump units and is effected at relatively low pressure, and consequently the connections between the metering device and these pump units comprise low. pressure piping.

A further object of this invention is to provide a fuel injection system for multi-cylinder interna-1 combustion engines in which the unit injectors are of the automatic type in which the actuating force for the high pressure fuel pump units is furnished by the compressed gases of theV engine cylinders and a common metering device is used for all the automatic injectors, which z A,device may also control the timing of the begin-f ning of injection.

The invention further consists in the several features hereinafter set forth and more particularly dened by claims at the conclusion hereof.

In the drawings:

Fig. l is a diagrammatic view of a fuel injection system embodying the invention;

Fig. 2 is a vertical sectional view through a fuel injector usable in the system embodying the invention;

Fig. 3 is a view similar to Fig. 2 showing certain modifications;

Fig. 4 is a vertical sectional view through -a metering control device forming a part of the system embodying the invention.

Referring to the drawings and particularly Fig. 1, I have shown diagrammatically a fuel injection system in which the fuel and the control fluids are separate and in which branch piping A from a suitable fuel feed pump (not shown) itself may be used as the checking fluid in which instance the piping A is omitted and the injectors provided with a passage connecting their high pressure pump inlets to the fluid in the checking cylinders hereinafter described.

Referring to Fig. 2, where the unit injectorsv are of the automatic type, each injector comprises a housing formed of parts 5 and 6, an actuating piston 1 reciprocating in said housing, a high pressure pump barrel 8 in said piston, a relatively stationary pump plunger 9 working in said barrel and a spring III interposed between said plunger and piston for holding said plunger against the top of part 5 and moving said piston downwardly.

The part 5 is a cylinder having a bore il with passages i2. I3, and I4 communicating therewith. The part 8 is a cylindrical ring with a tapered valve seat or bore i5. These parts are held in assembled relation by a threaded connection I6 with the engine head i1.

The piston 'l has a conical end i8 normally seating on the seat i5, piston rings i9. a fuel groove 28 communicating with the passage I4 and is diiferentially bored to provide a threaded bore 2l, plain bores 22 and 23 and shoulders 24 and 2i.

A spray nozzle 28 fits bore 2 3 with its flanged I end 21 abutting shoulder 25 and is recessed to receive a valve seat member 28 which abuts against the barrel 8, this assembly being clamped in position by a nut 29 engaging the bore 2 I, a compressible gasket 30 being interposed between the anged end of said barrel and the shoulder 24. A discharge valve 3| acted on by spring 32 normally closes the opening in seat member 28 but opens under fuel pressure for the discharge of fuel through the orifices 33 in the nozzle 26. The barrel 8 has fuel inlets 34 controlled by plunger 9 and supplied with fuel through an annular groove 35 forming a piston cooling chamber and connected by a port 38 with the groove 20 where the checking fluid used is a lubricant, but if the fuel itself is used as the checking uid, then the checking fluid chamber 31 above the piston 8 connects by suitable grooves or passages with the groove 35 and the port 36 is omitted in which instance the passage I4 may be a lubricant supply passage. The head of the plunger 3 is grooved at 38 to allow passage of checking fluid through the passage I2 to the control device MT. With this construction when the gases in the combustion chamber C reach a pressure sufficient to overcome the loading of the spring I0, the piston 1 is moved outwardly, thus causing the plunger 9 to cover the ports 34, compress the fuel in the highpressure pump chamber until the loading of the spring 32 is overcome and fuel is discharged into the chamber C through the orifices 33 until the movement of piston 1 is checked.

Referring to Fig. 3, a member 33 is formed to provide a pump barrel. and an operating and checking piston cylinder 4l. A high pressure pump plunger 42 works in barrel 48 and is moved in its outward direction by a spring 43 and controls the fuel inlet port 44 which may be separate from the checking fluid, as shown, or receive its supply from the checking fluid chamber 45 provided with an inlet 4.and outlet 41 connectible with the control device MT.

An apertured valve seat member 48 is clamped to the lower end of member 33 by a nozzle member 49 having threaded connection with member 39 and provided with spray orifices 50 through which fuel flows on the opening of a discharge valve normally held against the seat 48 by aspring 52.

An operating piston 53 works in the cylinder 4 l.

.through a spring 60, so that while the stroke of the tappet 58 is constant, that of piston 53 and consequently plunger 42 is variable depending upon the amount of checking fluid in the chamber 45.

For controlling the time of injection and the amount of checking fluid in either the chamber 31 or 45, the control device MT shown in Fig. 4 includes a valve housing 6I provided with ports 62 communicating with the branch pipes G leading to the injectors I and an outlet 63 connected bv the pipe E with the pipe D and a rotary and longitudine-liv reciprocal valve 64 working in said rousing, said valve having a hollowed upper end with a triangular shaped notch providing control edges 65 and 55 adapted during the rotary movement of said valve to connect the outlet 63 .successively with the ports 52, the crank angle period of this connection being determined by the longitudinal positioning of said notch relative to said ports.

The valve 64 has a slidable key connection 61 with an intermediate rotary shaft 68 and is moved longitudinally in one direction by a forked lever 63 engaging in its annularly grooved lower end against the action of a spring 1i `to vary the position of control edges 65 and 56 relative to the ports 62 and consequently the amount of checking fluid successively released from the chambers 31 or 45 to thus control the amount of fluid in said chambers and hence the effective stroke movement of the piston 1 or 53. Shaft 58 may be driven directly through any suitable gear ratio from the engine crank shaft, but to vary the timing of the beginning of injection I have shown said shaft as connected by an adjustable angular advance drive coupling 12 with a shaftI 13 connected by gearing 14 with an engine driven shaft 15, said coupling having an annular groove 16 Aengaging a forked adjusting lever 11 whereby the\control edge of the valve may be advanced or retarded relative to the ports 62 and thus cause injection, during an available injection period, to occur sooner or later. The coupling 12 herein shown includes a sleeve slidably keyed at 13 to the shaft 13 and provided with oppositely disposed helical grooves 19 in which a pin 80 on the shaft 68 works.

With the above constructions since the area of the checking chamber 31 or 45 is not limited by the dimensions of the high pressure fuel plunger, the hydraulic checking pressures may be relatively low, for example, one to three hundred pounds per square inch, so that sealing of the valve 64 is facilitated.

I desire it to be understood that this invention is not to be limited to any particular form or arrangement of parts except in so far as such limitations are included in the claims.

Wha-t I claim as my invention is:

1. In a fuel injection system for internal combustion engines, the combination of a plurality of high pressure expansible chamber pump units, each including a movable element, means for reciprocating each of said movable elements, variable volume hydraulic stroke limiting means for said movable elements distinct from the chambers of said pump units including a metering device common tc all of said units for controlling the same during a cyclic period of the engine.

2. In a fuel injection system for internal combustion engines, the combination of a plurality of high pressure expansible chamber pump units,

each including a movable element, means for' reciprocating each of said movable elements, variable volume hydrau'icJ stroie limiting means for said movable elements distinct from the chambers of said pump units including valve means common to all of said units for controlling the hydraulic fluid of said stroke limiting means dur; ing a cyclic period of the engine.

3. In a fuel injection system for multi-cylinder internal combustion enginesl the combination with a fuel injector for each cylinder including an expansible chamber pump and a piston operatively connected to one of the elements of said pump and a chamber distinct from the chamber of said pump and containing a checking uid, of a metering control device including a control cylinder having ports respectively connected with said checking fiuid chambers and a control valve working in said cylinder and cooperating with said ports to determine the effective stroke of each of said pistons and con sequently the stroke of said pump, and means controlled by the engine for operating said control valve.

4. In a fuel injection system for multi-cylinder internal combustion engines, the combination with a fuel injector for each cylinder including an expansible chamber pump and a piston operatively connected to one of the elements of said pump and a chamber distinct from the chamber of said pump and containing a checking fluid, of a metering control device including a control cylinder having ports respectively connected with said checking fiuid chambers and 5 an engine driven rotary control valve mounted in said cylinder and cooperating with said ports to determine the amount of checking 'fluid released from said chambers to determine the effective stroke of each of said pistons.

5. In a fuel injection system for multi-cylinder internal combustion engines, the combination with a fuel injector for each cylinder including an expansible chamber pump and a piston operatively connected to one of the elements of said lo 6.. In a fuel injection system for multi-cylinden internal combustion engines, the combination with a fuel injector for each cylinder including an expansible chamber pump and a piston operatively connected to one of the elements of said pump and a chamber distinct from the chamber of said pump and containing a checking fluid, of a metering control device including a cylinder' having ports respectively connected with said checking fluid chambers and an engine driven longitudinally adjustable rotary control valve mounted in said cylinder and having control edges cooperatingwith said ports to deter-4 mine the amount of checking uid released from said checking fluid chambers tol determine the eiective stroke of each of said pistons.

"I, In a fuel injection system for multi-cylinder internal combustion engines. the combination with a fuel injector for each cylinder including a,

high pressure expansible chamber pump unit having a movable element and a piston movable moving said element, said piston being movable in a chamber distinct from the chamber of said pump unit and containing a checking fluid, of means common to all of said checking fluid 15 chambers and cyclically connected thereto to vary the amount of checking fluid released from said checking fluid chambers and thus vary th strokes of said movable elements.

LoUrs 0. FRENCH.

REFERENCES CITED The following references are of record in the file of this patent:

l! UNITED sTATEs PATENTS Number Name Date 2,027,360 Alden Jan. 14, 193s 2,133,849 Gambreu Dec. e, 193s u l f FOREIGN PATENTs Number Country l Date 187,950 Great Britain Nov. 29, 1923 468,360 Y (Ilfx'eatV Britain June 30, 1937 in response to engine compression pressure for

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