US3175545A - Fuel injection system - Google Patents

Description

March 30, 1965 F. BARFOD FUEL INJECTION SYSTEM Original Filed Aug. 31, 1953 2 Sheets-Sheet l QQ QS March 30, 1965 F. BARFoD FUEL INJECTION SYSTEM 2 Sheets-Sheet 2 Original Filed Aug. 31, 1953 lll- IIN

H u Illll/J l llll/lllllllllll'lf '1111111111 IN V UV TOR. ff/FM MRI-'00 BY %M /w TTORA/ir [lll/lll lll/lll United States Patent 3,175,545 FUEL INJECTIGN SYSTEM Frederik llarfod, Detroit, Mich., assigner to The Bendix Corporation, a corporation of Delaware Original application Aug. 31, 1953, Ser. No. 377,519, now Patent No. 2,786,460, dated Mar. 26, 1957. Divided and this application June 28, 1956, Ser. No. 594,658

The portion of the term of the patent subsequent to Mar. 26, 1974, has been disclaimed 9 Claims. (Cl. 12S-119) Tlhis is a division of my copending application Serial No. 377,519, filed August 3l, 1953, now U.S. Patent No. 2,786,460.

This invention relates to fuel supply systems or devices `for internal combustion engines and more particularly to devices or systems in which liquid fuel is supplied under positive pressure.

An object of the present invention is to provide an improved combination of fuel injection pump and metering system therefor.

Another object of the invention is to provide an improved fuel supply system which is readily adapted for use with various internal combustion engines having different operating characteristics and fuel requirements.

Another object of my invention is to provide a fuel injection system capable of accurately metering small quantities of fuel and delivering said fuel to a multiple cylinder internal combustion engine as separate charges for each cylinder.

A further object of my invention is to provide a system for supplying fuel un-der positive pressure to the manifold of an internal combustion engine in the form of small individual charges for each cylinder.

A still further object of my invention is to provide a fuel feeding system in which the fuel flow is automatically regulated in accordance with certain engine variables such as, for example, engine speed and engine charging pressure.

Other objects and advantages will be readily apparent from the following detailed description taken in connection with the appended drawings in which;

FGURE 1 is a diagrammatic View partially in section sho-wing the general arrangement of parts of one form of my improved fuel supply system as applied to an internal combustion engine;

FIGURE 2 is an enlarged view partially in section of the rotary distributor valve shown in FIGURE l;

FIGURE 3 is a partial view of the manifold of an internal combustion engine showing a supercharger in the induction passage;

FIGURE 4 is an enlarged view partially in section of a modified form of the rotary distributor valve.

Referring now to the drawings and in particular to FlGURE l, numeral 1d designates a gear pump, having Ian inlet 11 and an outlet 12. A multiplunger fuel -injection pump is shown at 13 having a fuel inlet 14 in communication with the outlet of the gear pump through a fuel metering control generally shown at 15. The gear pump is adapted to be driven by shaft 16 which is journaled at one end in a member 17 secured in the housing 1S and at the other end in a partition 19 which is formed in the housing and separates the gear pump from the chamber 2h of the injection pump. Opening into this chamber are pump cylinders 21 circularly disposed in an end member 22 which is secured to a flange `on the housing by suitable `bolts 23.

Shaft 16 is adapted to be driven by the engine (not shown) whereby the fuel discharged by the gear pump varies as -a function of engine speed. The fuel discharged by the gear pump is metered by the control unit as a function of engine charging pressure and/ or temperature. A quantity of metered fuel, depending on engine operat- "ice ing conditions and characteristics of the particular engine being supplied by my fuel feeding system, is bypassed to the inlet of the gear pump. The remainder of the metered fuel flows to the injection pump which delivers the fuel to the manifold of the engine in small individual charges for each cylinder.

The size of each charge is varied by a rotary distributor valve 24 which lis slidably disposed in -a cylindrical chamber 25. This chamber is located in the end member 22 concentrically with pump cylinders 21. The outer end of chamber 25 is closed by a plug 26 in which a spring loaded abutment member 27 is slidably carried.

A drive shaft 2S is splined at one end in common splineways with shaft 16 and is keyed at the other end with the valve 24 whereby the valve is free to move longitudinally on the shaft but is fixed for rotation therewith. A spring 29 encircles the shaft and is held in abutting relationship with the valve by a spring retainer 30. The rotary distributor valve is cylindrically shaped and has a reduced central portion 31 on which is formed a helical land 32 (FIGURE 2). A bore 33 traverses the reduced central portion, and an axial bore 34 connects the hollow interior of the valve with the inlet 14 of the injection pump. The helical land 32, as shown in FIGURE 2, terminates in a narrow raised portion 35 which extends across the redud portion between end lands 36 and 37. The interior of the valve 24 is normally in communication with the pump cylinders 21 through bore 33, passages 38 and port 39. Communication between the interior of the valve and the pump cylinders is, however, adapted to be cut off during `a certain portion of the rotation of the valve 24 by the helical land 32 coming into registration with passage 38. An abutment member 27 is provided to prevent spring 29 from moving the helical land out of registry with passage 3S and determines the minimum `fuel ow during normal operation of the engine. The abutment member 27, however, may be moved to the left as viewed in FiGURE 1, by an idle cut-off lever 4G to cause land 37 to move into registration with passage 38 and thereby cut off communication between the fuel inlet 14 and pumping cylinders 21.

An alternate means `for providing idle cut off is shown in FIGURE 4 wherein a radial bore 34a connects the bore 34 with annular groove 37a in the end land 37. With this arrangement the idle cut-off lever 40 moves gro-ove 37a into registration with passage 3S establishing continuous communication between the inlet 14 and the pumping cylinders 21 allowing `the cylinders to fill with fuel -on each suction stroke but causing the fuel to be returned to lthe inlet 14 rather than expelled through the discharge port 47 on each pumping stroke whereby the pump discharge is cut off.

'The number of pumping cylinders provided in the injection pump is correlated with the number of cylinders in the engine with which the fuel feeding system is adapted for use. Preferably, the pumping cylinders are alike in construction, and hence lthe description of one will suice for all. Pumping plunger 41 is slidably disposed in the cylinder 21 and is urged toward retracted position by a spring 42. The plunger is urged in the pumping direction in opposition to said spring, by a bearing ring 43 mounted on wobble plate 4.4i which is secured to an extension of shaft 16 Vand adapted for rotation therewith. A conduit 45, containing a check valve 46 connects the discharge port 47 in the end of the pumping cylinder with nozzle 48 located in the manifold 49. Although the nozzle shown is discharging into the mani-fold, it is to be understood that the nozzle could equally well be located in the cylinder wall of the engine.

A throttle body 69 with a throttle valve 61 mounted therein is secured to the manifold by suitable bolts (not shown). As shown in FIGURE 3, a supercharger 62 `of conventional design may also be included in the induction passage. A passageway 70 communicating with the induction passage on the engine side of the throttle and anterior to the supercharger, if included, supplies the engine charging pressureV to the control unit 71 in the fuel metering unit 15. The latter unit is interposed between the gear pump and the injection pump 13 to receive the entire output of the gear pump through passages 73 and 74 and to deliver a metered portion of that output to the inlet 14 of the injection pump. The remainder of the fuel is returned to the inlet of the gear pump through by-passes connected to each of the passages 73 and 74.

Passage l73 is connected tto the gear pump outlet 12 and the inlet 11 .through conduit 76, passageway 78, passage 80, chamber 20, bore 82 and passage 82. Valve 84 controls passage 73 and is connected to control unit 71 by a suitable linkage 86. 'Iihe control unit comprises a housing 88 defining a chamber 90 containing a bellows 92 urged toward extended position by an internally carried spring 94. A rod 96 secures one end yof the bellows to the linkage 86.

Conduit 76 is controlled by a pressure equalizing valve 98 which is freely reciprocable in said conduit between toro-idal members 100 to control the communication between conduit 76 and passageway 78. The outlet 12 of the gear pump is also connected to the inlet 11 through a Iby-pass consisting of passages 74, 102, 104, 106, restriction 107, passages 108, 80, chamber and bore 82. The passage 104 is separated from conduit 76 by valve 98 which is responsive to the pressure differential existing between the two conduits. A conduit 110 connects passage 74 posterior the metering restriction 112 to the inlet 14 of the injection pump. A temperature responsive v-alve 114 controlled by unit 116 extends into the metering restriction 112 and regulates the ow therethrough. The unit 116 consists of a housing 118 containing a bellows 120 which is connected to 'a temperature -bulb in the intake manifold through a tube 122. Valve 114 is centrally secured to a diaphragm 124 which seals one end of the housing. The bellows upon being heated expands to urge the diaphragm in a valve closing direction and is opposed in this movement by a spring 126.

A power enrichment system is provided a-t numeral 140, consisting of a power enrichment jet 142 connecting conduit 74 with conduit 76. The power enrichment jet is controlled by a valve 144 which on yone side is subjected to gear pump outlet pressure through conduits 74 and 146 andv on the other side to the force of a spring 148 and the pressure in conduit 76. At low and medium speeds the jet is open thereby by-passing a porti-on of the fuel from conduit 74 to the conduit 76 causing the quantity of fuel delivered to the inlet 14 of the injection pump to be decreased. At high speeds the gear pump discharge pressure is .suthcient to move valve 144 to clo-se the jet, thereby cutting orf the by-pass land causing an increase in the quan-tity yof fuel delivered to the injection pump.

In the operation of my fuel supply system, fuel under substantially constant pressure is supplied from a source (not shown) to the gear pump'inlet 11. The gear pump drive shaft 16 is adapted to be driven by the engine whereby fuel under a pressure varying as a function of engine speedis discharged through outlet 12 to metering restriction 112 and valve 84 through conduits 74 and 73 respectively.

The size of the metering jet 112 is varied by valve 114 as a function of manifold air temperature. Fuel passing through jet 112 is therefore metered as a function of engine speed and engine temperature. A portion of the fuel, thus metered, ows through passages 102 and 104 to act on one face of 'the pressure equalizing valve 98 and to urge said valve in a direction to close passage 78. With passage 78 closed, the entire output of the gear pump is confined to passage 74. The closing of valve 98 by fuel under pressure in passage 104, however, is opposed by fuel under pressure in conduit 76 acting on the opposite side of valve 98. The fuel pressure in conduit 76 is controlled by Valves 84, 144 and 98.

Valve 84 isV controlled by unit 71 whichis responsive to engine charging pressure. As the charging pressure increases, valve 84 is moved toward closed position reducing the fuel pressure in passage 76 and causing valve 98 to move in'a direction to'c'lose passage 78. Corl-V versely, as air charging pressure decreases, valve 84 is moved toward open position increasing the fuel pressure in passage 76 causing valve 98 to move in a direction to open passage 78. With passage 78 open, the portion of the gear pump discharge delivered to conduit 73 is bye passed to the pump inlet 11.

During low and medium speeds the power enrichment jet 142 is open, connecting conduit 74 with conduit 76 and thereby causing the fuel pressure in conduit 76 to be increased. During high speed operation, however, the pressure of the fuel in conduit 146, which varies` as 4a function of engine speed, is suiiicient to move the valve 144, in opposition to spring 148, to a position to cit olf the fuel flow through jet 142 thus causing a decrease in fuel pressure in the conduit 76. A decrease i'ri fuel pressure in conduit 76 causes valve 98 to close passage 78 thereby effecting an increased flow through metering jet 112.

It is apparent that the quantity of fuel entering passage 74 is dependent upon the quantity of fuel discharged by' the engine driven gear pump and the quantity of fuel by; passed through conduit 73 which is controlled byairA charging pressure responsive valve 84 and power enrich= ment jet 142. The quantity of fuel passing through the metering jet 112 and temperature responsive valve 114 is, therefore, metered in response to engine speed; engine charging pressure and air inlet temperature. A portion of this metered fuel, the amount of which is determined by a particular engine operating characf teristic, is by-passed through passages 102, 104, 106, 108, 80, chamber 20 and bore 82 to the inlet 11 of the geaf Pump- The remainder of the metered fuel passes through conf' duit to the injection pump inlet 14 which is controlled by a rotary distributor valve 24 slidably mounted on an engine driven shaft for rotation therewith. The valve 24 is cylindrically shaped having a hollow interior in comJ muncation with the inlet 14 through the 'axial bor' 34 and with the pumping cylinders 21 through radial bofe' 33, passage 38 and port 39. The helical land 32 is adapted to close off the passage 38 during a portion of a rotation of the v-alve 24 thereby preventing the return of fuel from pumping cylinders 21 during at least a portion of the pumping stroke. The effective pumping capacity or amount of fuel delivered per stroke of the injection pump 13 may therefore be easily varied by varying Ithe amount of time per pumping stroke that the helical land 32 is in registration with the passage 38 which in t-urn is determined by the longitudinal position of the valve 24 with respect to the passage 38. 'I'he longitudinal position of the valve 24 is affected by the force of metered fuel acting on one side 24 of the valve which, in opposition to spring 29, urges the land 32 into increasingly greater registration with passage 33 to cause an increase in the size of the charge delivered by the pumping cylinder.

I have discovered that in order to supply the correct fuel-air mixture to the engine, when the quantity of fuel'` deliveredto the metering unit varies as a function off engine speed, a certain portion of the metered fuel, de-l pending upon the particular engine characteristics, must. be by-passed. In my fuel feeding system I provide a means for by-passing a portionof the metered fuel consisting of passages 102, 104, 106, l108, 80,'chamber 20 and bore 82. The quantity of fuel by-passes in any par-v ticular engine is determined by the size of restriction 107 and the pressure differential across it. This pressure dif-- ferential is that which exists between the gear pump inlet pressure and metered fuel pressure, which in turn is a function of the spring rate of spring 29 that opposes the movement of valve 24 in a direction to increase the pumping of metered fuel.

In an installation where it is desired to by-pass an approximately constant quantity of fuel, a spring is selected having a low spring rate so that a relatively small increase in metered fuel pressure is required to move valve 24 from minimum to maximum flow position. This results in a relatively small increase in the pressure differential across restriction 107 whereby the amount of fuel by-pass is held between narrow limits approaching constant ow. In other installations the quantity of fuel by-passed may be changed simply by selecting the proper restriction 107 and/or spring 29 to satisfy the requirements of any particular engine.

Fuel for idling is provided by the raised portion 35 on the valve 24 which is kept in registration with the passage 38 by abutment 27 when the fuel pressure acting on one side of valve 24 is less than the force of spring 29. The idle cut-off lever 40 forces the abutment member 27 to move the valve 24 in a direction to cause land 37 to come into registration with passage 38 whereby all fuel is cut-off to the pumping cylinders 21.

Extreme compactness of the fuel metering system is obtained by locating the single rotary distributor valve concentric with the circularly disposed pump plungers and axially aligning the valve with the gear and injection pumps whereby a common drive shaft may be utilized. This structure not only provides a greater compactness but also a greater freedom from injection errors caused by faulty timing of the component parts of the system.

I have discovered that by obtaining the engine charging pressure on the engine side of the throttle valve anterior to the supercharger that I am able to eliminate unpredictable errors such as manifold back pressures and the like whereby I am able to more accurately provide the correct fuel air mixture to the engine under all operating conditions than the known devices which utilize the charging pressure posterior to the supercharger.

While only one preferred embodiment of my invention has been described it will be readily apparent to those skilled in the art that many changes or arrangements of parts may be made without departing from the spirit of my invention.

I claim:

1. In a fuel supply system for an internal combustion engine, a fuel conduit, means for supplying fuel to said conduit at a rate proportional to engine speed, a first orifice in said conduit, a variable orifice means in said conduit upstream of said first orifice for diverting fuel from said conduit, and means for statically equalizing the pressure downstream of said first orifice and the pressure downstream of said variable orifice, said variable orifice means being responsive to parameters refiecting air intake to said engine in each revolution of said engine.

2. In a fuel supply system for -an internal combustion engine, a fuel conduit, means for supplying fuel to said conduit at a rate proportional to engine speed, a first orifice in said conduit, a variable orifice means in said conduit upstream of said first orifice for diver-ting fuel from said conduit, means statically equalizing the pressure downstream of said first orifice and the pressure downstream of said variable orifice means, means automatically controlling said variable orifice means in accordance with parameters reflecting air intake to said engine in each revolution of said engine, said automatic controlling means acting to decrease the open area of said variable orifice means upon an increase in air intake to said enengine in each revolution of said engine.

3. A fuel system for an internal combustion engine comprising a metering valve, a source of fuel under pressure, means for delivering fuel from said source to the 6 inlet of said metering valve, and means subject to the pressure of fuel at said source for controlling the pressure of fuel at the outlet of said metering valve.

4. A fuel system for an internal combustion engine comprising a metering valve, a source of fuel at constant pressure, means for delivering fuel from said source to the inlet of said metering valve at a pressure dependent upon engine speed, and means subject to the pressure of fuel at said source for controlling the pressure of fuel at the outlet side of said metering valve.

5 In a fuel supply system for an engine, a fuel conduit, means for supplying fuel to said conduit at a rate proportional to engine speed, yan orifice in said ifuel conduit, a control conduit leading off said fuel conduit upstream of said orifice, a variable orifice connecting the control conduit to said fuel conduit and variable to vary the fuel fed to the engine, an orifice in said control conduit, and fuel flow control means connecting to both of said conduits downstream of said orifice and operative to supply fuel to the engine responsive to the pressures of said conduit-s.

6. In a fuel injection pump having a housing, a plurality of cylinders in said housing, a plunger in each of said cylinders, an inlet for each of said cylinders, a valve mounted in said housing for rotational axial movement, a first land portion formed on said valve for intermittent registration with said inlets when said valve is rotated in a first axial position, and a second land portion formed on said valve for continuous registration with said inlets when said valve is rotated in a second axial position.

7. In a fuel injection pump having a housing, a plurality of cylinders in said housing, a plunger in each of said cylinders, an inlet for each of said cylinders, a valve mounted in said housing for rotational and axial movement, a first land portion `formed on said valve for intermittent registration With said inlets when said valve is rotated in a first axial position, a second land portion formed on said valve for continuous registration with said inlets when said valve is rotated in a second axial position, and an abutment member movable into engagement with said valve to determine in one position of said member the minimum intermittent registration of said first land portion and movable to a second position to move said second land portion to said second axial position.

8. A fuel injection pump comprising a housing, a plurality of cylinders in said housing, a plunger in each of said cylinders, an inlet for each of said cyinders, a rotary valve disposed in said housing for variable registration with said inlets for varying the effective pump stroke of said plunger by controlling the duration of valve registration with an inlet during a pumping stroke, resilient means operatively engaging said valve to urge said valve in a direction of decrease the effective stroke of said plunger-s, an abutment means formed to engage said valve having a first position to limit movement of said valve in said effective stroke decreasing direction, and means for applying metered fluid pressure to said valve for moving said valve in a direction to increase said effective stroke.

9. A fuel injection pump comprisingof a housing, a plurality of cylinders in said housing, a plunger in each of said cylinders, an inlet for each of said cylinders, a rotary valve disposed in lsaid housing for variable registration with said inlets for varying the effective pump stroke of said plunger by controlling the duration of valve registration with an inlet during a pumping stroke, resilient means operatively engaging said valve to urge said valve in a direction to decrease the effective stroke of said plungers, an abutment means formed to engage -said valve having a first position to limit movement of said valve in said effective stroke decreasing direction, and means for moving said abutment means to second position to thereby move said valve to a position to continuously close said inlets to thereby render said plungers substantially ineffective.

(References on following page) 'References Cited bythe Examiner UNITED STATES PATENTS 8 FOREIGN PATENTS 1,000,361 2/52 France.

`1 123 139 RICHARD B. WILKINSON, Primm Examiner.

smith 10s-17s XV 5 LAURENCE v. EFNER, KARL J. ALBREYCHT, Parker 103-2 RALPH Hi BRAUNER, Examners.

Stoyke 103-2 Wahlmark 103-2 Schindele 123--139 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No 3,175, 545 March 30, 1965 Frederik Barfod It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 6, line 24, after "rotational" insert and line 52, for "of", first occurrence read to line 59, AStrike out "of".

Signed and sealed this 28th day of September 1965.

(SEAL) Attest:

ERNEST W. SWIDER EDWARD J. BRENNER Attesting Officer Commissioner of Patents

Claims (1)

1. IN A FUEL SUPPLY SYSTEM FOR AN INTERNAL COMBUSTION ENGINE, A FUEL CONDUIT, MEANS FOR SUPPLYING FUEL TO SAID CONDUIT AT A RATE PROPORTIONAL TO ENGINE SPEED, A FIRST ORIFICE IN SAID CONDUIT, A VARIABLE ORIFICE MEANS IN SIAD CONDUIT UPSTREAM OF SAID FIRST ORIFICE FOR DIVERTING FUEL FROM SAID CONDUIT, AND MEANS FOR STATICALLY EQUALIZING THE PRESSURE DOWNSTREAM OF SAID FIRST ORIFICE AND THE PRESSURE DOWNSTREAM OF SAID VARIABLE ORIFICE, SAID VARIABLE ORIFICE MEANS BEING RESPONSIVE TOO PARAMETERS REFLECTING AIR INTAKE TO SAID ENGINE IN EACH REVOLUTION OF SAID ENGINE.

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