Fuel Injection System

Abstract

In an electronically controlled fuel injection system, the air inlet body and the fuel rails are secured by a bracket whereby the air and fuel metering components of the system which are mounted thereon may be tested and shipped in a unitary package.

Description

This invention relates to a fuel injection system having numerous advantages of construction and operation over those available heretofore.

Particular advantages may be noted in the provision of a bracket interconnecting the air inlet body and the fuel rails. This allows the air metering components carried on the air inlet body and the fuel metering components carried on the fuel rails to be tested and shipped as a single unit. If desired, the bracket may be removed during installation of the air inlet body and fuel rails on an engine.

The details as well as other objects and advantages of this invention are set forth in the remainder of the specification and are shown in the drawings in which:

FIG. 1 is a side elevational view of a fuel injection system, also showing an air cleaner mounted on the air inlet body but omitting any showing of the inlet manifold and other engine components for clarity of detail;

FIG. 2 is a front elevational view of the fuel injection system, showing its relationship to the inlet manifold and cylinder heads;

FIG. 3 is a top plan view of the fuel injection system showing the bracket securing the air inlet body and the fuel rails into a single package for testing and shipping;

FIG. 4 is a sectional view, as it would appear along line 4--4 of FIG. 3, showing one of the injectors mounted in the fuel rails and also showing the relationship of the components to the induction passage in the inlet manifold and cylinder heads;

FIG. 5 is a sectional view, as it would appear along line 5--5 of FIG. 3, showing one of the air inlet fittings for the atmospheric air galleries in the fuel rails;

FIG. 6 is a sectional view along line 6--6 of FIG. 4 showing the constructional details of one of the fuel injectors;

FIG. 7 is a sectional view along line 7--7 of FIG. 2 showing the mounting of a fuel temperature thermistor;

FIG. 8 is a bottom plan view of the air inlet body and the heat conducting pad; and

FIG. 9 is a sectional view along line 9--9 of FIG. 8 showing further details of the heat conducting pad.

Throughout the drawings, some portions of the electrical wiring and the air and vacuum hoses are illustrated but most portions of such have been omitted for a clearer illustration of other components of the fuel injection system.

Referring to the drawings, the fuel injection system includes an air inlet body 10 and a pair of extruded fuel rails 12 and 14. Mounted on an inlet manifold 16 which in turn is mounted on cylinder heads 18 and 20, air inlet body 10 has a pair of air inlet passages 22 and 24 which register with the induction passage 26 extending through inlet manifold 16 and heads 18 and 20 to the combustion chamber inlet ports 27. Throttles 28 and 30 are disposed in inlet passages 22 and 24 on a rotatable shaft 32 for controlling air flow through induction passage 26.

Air inlet body 10 also is provided with a transducer 34, such as that described in U.S. Ser. No. 202,760, filed Nov. 29, 1971, which measures the absolute pressure in air inlet passages 22 and 24 and induction passage 26 downstream of throttles 28 and 30 and provides an electrical signal proportional thereto.

Air inlet body 10 also has provision for a curb idle adjustment 36 and a fast idle control valve 38 such as those shown in U.S. Ser. No. 41,141, filed May 25, 1970, now U.S. Pat. No. 3,645,509.

If desired, air inlet body 10 also may include provision for a transducer 40 which provides an electrical signal indicative of a sudden increase in pressure in air inlet passages 22 and 24 and induction passage 26 downstream of throttles 28 and 30 and thus indicative of engine acceleration.

In addition, air inlet body 10 includes provision for mounting a thermistor 42 which senses the temperature of the air entering air inlet passages 22 and 24 and induction passage 26. Further, air inlet body 10 may include provision for an electrical switch 44 which is opened and closed by a throttle lever 46 secured on throttle shaft 32 and which thus indicates the position of throttles 28 and 30. An adjusting screw 48 may be provided to limit throttle closing movement of throttle lever 46.

A heat conducting pad 50 extends horizontally from air inlet body 10 toward the rear of the engine. As shown in FIG. 8, a drilled passage 52 provides a manifold vacuum tap to which the manifold vacuum connection 54 shown in FIG. 3 may be mounted. Other fittings 56 also shown in FIG. 3 may be provided for various vacuum signals created as throttle 30 traverses various ports (not shown) provided in air inlet passage 24. Other vacuum taps, such as that shown at 58 in FIG. 2, also may be provided.

As shown in FIGS. 1 and 3, an electronic package 60 is mounted on heat conducting pad 50. Electronic package 60 receives electrical signals from the components, such as transducers 34 and 40, throttle switch 44, and thermistor 42, which meter air flow to the engine and controls energization of the injectors which meter fuel flow to the engine as described below. Referring to FIGS. 8 and 9, electronic package 60 is designed to mate with the heat transfer surface 62 of pad 50 whereby heat generated during operation of electronic package 60 may be conducted into heat conducting pad 50. The lower surface of pad 50 has a plurality of elongated recesses 64 which define a plurality of fins 66 therebetween. Fins 66 radiate heat from pad 50 into the atmosphere ambient pad 50, space being provided between the lower portion of pad 50 and inlet manifold 16 to permit air circulation. Recesses 64 and fins 66 are generally parallel and their major axes extend longitudinally toward air inlet body 10, thus facilitating heat conduction to air inlet passages 22 and 24. Heat generated during operation of electronic package 60 also is dissipated, therefore, into the air flowing through inlet passages 22 and 24 to induction passage 26.

Still referring to FIGS. 8 and 9, it may be noted that several ports 68 and 70 provide openings from air inlet passages 22 and 24, below throttles 28 and 30, to manifold pressure chambers 72 and 74. Manifold vacuum passage 52 extends from chamber 74, while manifold pressure transducer 34, idle air controls 36 and 38, and acceleration transducer 40, as well as other desired components, are associated with chamber 72.

Fuel rail 12 extends longitudinally along the right-hand bank of combustion chambers while fuel rail 14 extends longitudinally along the left-hand bank of combustion chambers. Rails 12 and 14 are shown in FIG. 2 as being mounted on inlet manifold 16, but provision could be made for mounting the rails on cylinder heads 18 and 20, if desired.

As shown in FIGS. 4 and 5, rails 12 and 14 have fuel passages 76 and air passages or galleries 78 which are formed during the process of extruding rails 12 and 14. Air galleries 78 have fittings 80 provided with hoses 82 to receive air from an air cleaner 84. As shown in FIG. 1, air cleaner 84 is supported by an adapter ring 85, received on a ledge 86 formed about air inlet body 10, and is secured by a stud 87.

Each rail 12 and 14 has a plurality of injectors 88 retained, by clamps 90 as shown in FIG. 3, in sockets 92 formed as shown in FIG. 4. Sockets 92 intersect fuel passages 76, and "O" rings 94 surrounding injectors 88 above and below passages 76 prevent leakage of fuel from sockets 92.

As shown in FIG. 6, each injector 88 has a screen 96 through which fuel is received from passage 76. Fuel passes from screen 96 through an opening 98 in the injector body 100 and then through a central bore 102 in the nozzle 103. A valve plunger 104 controls flow of fuel from bore 102 through nozzle opening 106. When energized by electronic package 60, a solenoid coil 108 lifts a magnetically responsive member 110 secured on the end of valve plunger 104, thus metering and delivering fuel from fuel passage 76 through injector socket 92, screen 96, opening 98, bore 102, and opening 106 into the base region 112 of socket 92. Nozzle opening 106 sprays the fuel through a critical flow orifice member 114 which is disposed in the outlet 115 opening from base region 112 of socket 92. Orifice members 114 are aimed through induction passage 26 toward the inlet ports 27 for the combustion chambers 115 located at the ends of induction passage 26.

Branch passages 116 extend from air galleries 78 to base regions 112 of sockets 92 to provide atmospheric pressure regions at the outlets of injectors 88 and to supply a constant flow of air through orifice members 114. Branch passages 116 receive plugs 118 at the outer ends.

As best shown in FIG. 3, the rearward end of rail 14 is provided with a filter housing 120 which receives fuel through a fitting 122 from a fuel pump such as that set forth in U.S. Ser. No. 211,934, filed Dec. 27, 1971. Filter housing 120 supplies fuel to fuel passage 76 in rail 14 and, through a crossover pipe 124, to a similar fuel passage in rail 12. A fitting 126 may be provided on the rearward end of rail 12 to receive fuel from crossover pipe 124. At the forward end of rail 14, a fitting 128 houses a fuel temperature responsive thermistor 129 and provides a connection between fuel passage 76 in rail 14 and a crossover pipe 130 which extends to a fitting 132 at the forward end of rail 12. Fitting 132 includes means for bleeding fuel vapor from fuel passages 76 in rails 12 and 14 as set forth in, U.S. Ser. No. 221,640, filed Jan. 28, 1972.

As shown in FIG. 3, a bracket 134 is bolted at its outboard ends 136 and 138 to rails 12 and 14 and has a central portion 140 which is received on air cleaner adapter ring ledge 86 formed about air inlet body 10. A central arm 144 carries a bolt 146 which is received in a hole tapped in body 10 to receive air cleaner stud 87, thereby securing bracket 134 to air inlet body 10. By this means, air inlet body 10 and rails 12 and 14 are secured in a single package whereby both air and fuel metering components of the fuel injection system may be tested and shipped as a single unit. If desired, the bracket may be removed during installation of the air inlet body 10 and rails 12 and 14 on the engine.

Claims

I claim:

1. A fuel injection system for an internal combustion engine having a group of longitudinally spaced combustion chambers, each of said combustion chambers having air and fuel inlet means, said engine further having an intake manifold including air induction passage means extending to said air inlet means for said combustion chambers, said fuel injection system comprising:

an air inlet body having an air inlet passage adapted for mounting on said intake manifold with said air inlet passage in registration with said air induction passage means whereby air flow to said combustion chambers will flow through said air inlet passage, said air induction passage means, and said air inlet means, said air inlet body including means for metering air flow through said air inlet passage to said combustion chambers,

a longitudinally extending fuel rail defining a fuel passage having a plurality of fuel outlets adapted for mounting on said engine with the fuel outlets thereof in registration with said fuel inlet means for said combustion chambers, said fuel rail having recesses therein associated with said fuel outlets and means received in said recesses and controlled by said air flow metering means for metering fuel flow through said fuel outlets to said combustion chambers,

and a bracket securing said fuel rail to said air inlet body whereby said air and fuel metering means may be tested and shipped as a single unit.