GB2031064A - Internal Combustion Engine Fuel Injector Mechanism - Google Patents

Abstract

An electromagnetic fuel injector 30 is supported by socket 29 in a position whereby its spray tip end is positioned for injecting fuel into the associated throttle bore, the injector 30 forming with the wall of the socket, an annular fuel supply well 41 in flow communication with the inlet ports of the fuel injector and an upper fuel drain chamber 42 in flow communication with the fuel supply well so as to permit any fuel vapour in well 41 to rise into chamber 42 and be purged. A low pressure fuel supply passage 66 supplies fuel to the fuel well in an amount in excess of that discharged by the injector to effect cooling, return drain passage 71 from the fuel drain chamber 42, communicating via pressure regulator 57 with a fuel supply return line 75. <IMAGE>

Description

SPECIFICATION Internal Combustion Engine Fuel Injector Mechanism This invention relates to an induction mixture forming device for internal combustion engines and, in particular, to a fuel injector mechanism for use in a low pressure throttle body injection apparatus of the type used for supplying an air/fuel mixture into the intake manifold of a petrol engine.

Various types of so-called pressurised carburetor systems have been proposed in the past for supplying an induction air/fuel mixture to an engine. One such type of pressurized carburetor system is, in effect, a type of fuel injection system having one or two electromagnetic fuel injectors positioned at a common point so as to supply fuel into the induction system for the engine so that the resulting air/fuel mixture can be supplied by the usual intake manifold to all of the cylinders of the engine.

Because of the high volatility of petrol at low pressure and at elevated temperatures and altitudes, most such prior art fuel injection type pressure carburetors have included therein a fuel pressure pump such as a gear pump. This pump pressurizes the fuel, usually supplied to it by a low pressure fuel pump from the engine fuel tank, to a higher pressure, usually a pressure of about 2810 g/cm2 or higher, in order to prevent or reduce fuel vapour problems in the system which could result in vapour lock or the loss of power during engine operation.

However, with the availability now of improved electromagnetic fuel injectors, it is now possible to operate such a system with fuel supplied to the injectors at a nominal low pressure of 420 g/cm2-1 055 g/cm2, for example. Thus the high pressure fuel pump, which was normally used in the prior art fuel injection systems, including pressurized carburetors, is no longer required in systems having such electromagnetic fuel injectors incorporated therein. It will be apparent that fuel at such a low supply pressure can be provided, for example, by the use of an lnexpeRsive in-tank fuel supply pump.

This latter type fuel injection or pressurized carburetor system may be referred to as a throttle body injection system and the air/fuel mixing element thereof, a throttle body injection apparatus. However, in order for such apparatus to function properly with normal variations in ambient temperature and atmospheric pressure, the apparatus must be capable of use with petrol fuel supplied at a low supply pressure in such a manner as to prevent or reduce fuel vapours in the apparatus.

The present invention provides an injector mechanism for a throttle body injection apparatus for use with a petrol engine. The injector mechanism for the throttle body injection apparatus is adapted to be mounted above the throttle body thereof, the throttle body having either a pair of spaced apart upstanding throttle bores or a single upstanding throttle bore therein, the flow through each throttle bore being controlled by a throttle valve. The injector mechanism which also functions as an injector holder, is thus provided with either a pair of spaced apart sockets or with a single socket, each such socket being of configuration to support an electromagnetic fuel injector therein. Each electromagnetic fuel injector is preferably positioned so as to be coaxial with an associated throttle bore so as to effect discharge of fuel into that throttle bore.A fuel injector, as mounted in its socket, defines therewith a lower fuel supply well in flow communication with the port passages in the lower end of that injector, and an interconnected upper drain chamber. The lower fuel supply chamber is connected by an inlet supply passage to a source of fuel at low pressure while the upper fuel drain chamber is connected by a drain passage to a conventional fuel tank or reservoir, whereby any fuel vapour present in the supply chamber will rise up into the drain chamber to be conveyed by liquid fuel back to the fuel reservoir.

Preferably, the fuel injector coacts with the housing in which it is supported to define an annular fuel well supplying fuel to the valve seat area of the injector and an annular drain well above and connected to the fuel well, whereby any vapour in the fuel well can rise into the drain well, excess fuel in the fuel well flowing into the drain well for return therefrom to the fuel tank so that a substantial outer axial extent of the injector is effectively cooled by the fuel flow.

The injector preferably forms with the housing an annular through-flow, vertical fuel chamber the lower portion of which is in communciation with the interior of the injector adjacent to the flow control valve thereof.

A preferred embodiment of the invention is hereinafter described with reference to the accompanying drawings, in which: Figure 1 is an elevation of a low pressure throttle body injection apparatus for an internal combustion engine, with an injector mechanism in accordance with the invention associated therewith, the normal engine air cleaner associated with the apparatus being illustrated only in fragmentary form; Figure 2 is a plan of the throttle body injection apparatus, as viewed in the direction of the arrows 2-2 of Figure 1 but with the air cleaner removed; Figure 3 is a section on the line 3-3 of Figure 1, with the pressure regulator and fuel injectors removed from the fuel body of the injector mechanism to show the internal details of the fuel body.

Figure 4 is a fragmentary section on the line 4-4 of Figure 2, with the pressure regulator and a fuel injector of the throttle body injection apparatus shown in elevation; and Figure 5 is a fragmentary section on the line 5-5 of Figure 2 with the pressure regulator shown in elevation.

The drawings show a throttle body injection apparatus 5 which includes a throttle body 10 with an injector mechanism 11 in accordance with the invention mounted thereon. As shown in Figure 1, the cylindrical depending outlet end of a conventional air cleaner 6 is supported on the upper surface of the throttle body 10 adjacent its outer peripheral edge portion so that the bottom portion of the air cleaner casing around the outlet for the air cleaner loosely encircle the injector mechanism 11, so as to form therewith an atmospheric air induction flow passage 7. In the construction illustrated, the injector mechanism 11 has a fuel body housing that includes a fuel body 12 and a fuel body cover 14 secured together into a unitary assembly.

The throttle body shown has a flat lower base surface 1 5 for abutment with a machined mounting pad of an engine intake manifold, not shown, or with an apertured mounting plate of heat insulating material (also not shown) sandwiched therebetween. Throttle body 10 also has an opposed, upper surface 1 6 spaced from the surface 15, the upper surface 16 having arcuate tab portions 1 7 extending upwardly therefrom and circumferentially spaced apart radially inwardly of the outer peripheral edge of surface 1 6 so as to effect proper alignment of the lower circular rim of the air cleaner 6.

The throttle body 1 in this construction, is provided with a pair of spaced apart upstanding throttle bores 20, only one of which is shown in Figure 4, extending therethrough from the upper surface 1 6 to the lower base surface 1 5. Flow through each throttle bore 20 is controlled by a throttle valve 21 fixed to a throttle shaft 22 that intersects both throttle bores and is pivotally mounted in the throttle body. The throttle shaft 22 is connectable to a throttle valve actuation mechanism, not shown.Similarly, other elements, such as air flow and air temperature sensors or vacuum connections, which may be associated with the throttle body 10 as part of the control system for the associated fuel injection system or other systems are not illustrated or described since they are not deemed necessary for an understanding of the subject invention.

The fuel body 12, as shown in Figures 2 and 3, is preferably of-as small and open configuration as possible so as not adversely to affect flow of air through the air induction flow passage 7 into the throttle bores 20 of the throttle body. For this purpose, the fuel body 12 which may be made as a casting of heat conducting material, in the construction shown, includes a side pressure regulator portion 24, a pair of injector holder portions 25, and a pair of support legs 26. Each support leg 26 interconnects the pressure regulator body 24 with an associated injector holder portion 25 in spaced apart relationship to each other.The pressure regulator portion 24 and the injector holder portions 25 are provided with integral aperture mounting pads 27 and 27a, respectively, for use in securing the injector mechanism 11 to the throttle body 10, as by threaded fasteners 28 and 28a, respectively. A gasket 8, also of heat insulating material, is located between the upper surface 1 6 of the throttle body 10 and the adjacent bottom surfaces of the fuel body 12. As shown in Figures 2 and 4, the fuel body cover 14 is also secured to the fuel body 12 by fasteners 28b and also by the fasteners 28a, these latter fasteners extending through suitable apertures in the cover 14 and the body 1 2 (Figure 4) for threaded engagement into threaded apertures provided for this purpose in fuel body 12.

To provide for the injection of fuel into the air stream flowing through the throttle bores 20, a pair of electromagnetic fuel injectors 30 are supported in a pair of spaced apart sockets provided for this purpose in the injector holder portions 25 of the fuel body 12. Each fuel injector 30 is positioned so as to have its spray tip end 30a positioned above and coaxial to an associated throttle bore to discharge fuel into only that throttle bore 20. The electromagnetic fuel injectors 30 are each of a type capable of operation in a predetermined manner when supplied with fuel- at a nominal low pressure, for example, at a supply pressure of 6 to 1 5 psi. Each fuel injector 30 adjacent to its lower end has a plurality of side port passages, not shown, that are substantially horizontally aligned closely adjacent to the metering element, not shown, of the injector.These side port passages are not illustrated, in the construction shown, since a fuel filter material 90 that is supported by an open cylindrical filter support frame 91, secured, as by a press fit, to the portion of the injector housing is positioned as so to overlie these side port passages and effect filtering of fuel prior to its flow to the metering element, not shown, of the fuel injector.

Fuel to be injected by the electromagnetic fuel injectors 30 is supplied from a fuel tank, not shown, by a low pressure supply pump, not shown. This pump, because of the use of a low pressure fuel supply, referred to above, is preferably a turbine type pump, as distinguished from a positive dispiacement pump. Such pump is preferably located in the fuel tank and the tank preferably has incorporated therein a bottom reservoir so as to ensure a constant supply of fuel to the intank pump even at low fuel level and severe maneuvering conditions. At such location, the fuel wouid have little or no vapour entrapped therein.

The fuel, under low pressure, is conveyed from the fuel tank to the fuel injectors 30 by a supply conduit, not shown, to the inlet 66 (Figure 5) of a fuel delivery passage means in the injector mechanism 11 for flow to the fuel injectors as hereinafter described. Excess fuel delivered to these fuel injectors 30, as described further hereafter, is returned to the fuel tank through a return conduit, not shown, from the outlet end 76 (Figure 5) of drain passage means in the injector mechanism.

In the embodiment shown, each of the injector holder portions 25 of the fuel body 12 has a socket 29 in which an associated fuel injector 30 is mounted, each socket 29, being formed by a through stepped bore in each of the holder portions 25. Each socket is preferably located so as to be substantially coaxial with an associated throttle bore 20 in the throttle body 10, as shown in Figure 4, and each such bore is sized so as to correspond to the configuration of the electromagnetic fuel injector 30 to be mounted therein, all in a manner and for a purpose to be described.

As shown in Figure 4, each such stepped vertical bore provides a cylindrical upper wall 31 of limited axial extent, a cylindrical intermediate upper wall 32, a cylindrical lower intermediate wall 33, a cylindrical lower wall 34 and a cylindrical terminal wall 35. Such walls are progressively reduced in diameter relative to the wail next above. Walls 31 and 32 are interconnected by a flat shoulder 36. Walls 32 and 33 are connected by a bevel shoulder 37 and connecting flat shoulder 37a. Walls 33 and 34 are connected by a bevel shoulder 38. Walls 34 and 35 are connected by a flat shoulder 39.

An electromagnetic fuel injector 30 is retained in the socket 29 in which it is mounted, by a portion of the fuel body cover 14. As shown in Figure 4, the fuel body cover 14 has shaped stepped bores therein to form apertures 40 therethrough, only one of which is shown, which provide access to the electrical terminals 30b of the electromagnetic fuel injectors 30. Electrical control circuit wires from an electronic control circuit, not shown, ure attachable to the terminals 30b so as to energize and de-energize each of the injectors 30 as a function of engine operation in a desired manner, as known in the art. An arched open-sided extension 1 4a of the cover 14 partly encloses the protruding ends of the terminals 30b of each of the iniectors 30.

Each electromagnetic fuel injector 30 is positioned in its associated socket so that its spray tip end 30a, Figure 4, is axially spaced by a predetermined distance above the inlet end of the throttle bore 20 with which it is associated. The spray cone of atomized fuel discharged therefrom is directed toward the associated throttle bore wall above the throttle valve and also toward the throttle valve 21 on its upstream side in terms of the direction of induction fluid flow through the throttle bore.

In accordance with the invention, the lower intermediate portion 30c of the outer housing of each electromagnetic fuel injector 30 with the plurality of fuel inlet port passages therein, not shown, forms with the lower intermediate wall 33 and the bevel shoulder 38 of its associated socket an annular lower fuel supply well 41, while the upper intermediate portion 30d of the outer housing of the fuel injector 30 forms with the intermediate upper wall 32 and bevel shoulder 37 together with the interconnected flat shoulder 37a thereof an upper fuel drain well 42. The lower fuel supply well 41 is connected in flow communication with the upper fuel drain well 42 in a manner and for a purpose to be described.

Seals, such as O-ring seals 44 and 44a are positioned to effect a sealed connection between the housing of the electromagnetic fuel injector 30 and surfaces of walls 31 and 34, respectively, of the socket with which it is associated above the drain well 42 and below the supply well 41, respectively, as shown in Figure 3.

The pressure regulator portion 24 of the fuel body 12, as shown in Figures 4 and 5, is formed with a stepped bore therethrough to provide, in succession starting from its upper surface 54, an internal cylindrical upper wall 45, a cylindrical upper intermediate wall 46, a cylindrical lower intermediate wall 47 and a cylindrical lower wall 48. Such walls are of progressively reduced internal diameters relative to the wall next above.

Walls 45 and 46 are interconnected by a radial flat shoulder 50. Walls 46 and 47 are interconnected by a radial flat shoulder 51. Walls 47 and 48 are interconnected by a radial flat shoulder 52.

As shown in Figures 4 and 5, the fuel body cover 1 4 has a lower flat surface 53 for abutment with the upper flat surface 54 of the fuel body 12 or with a gasket 55 sandwiched therebetween.

The portion of the fuel body cover 14 which overlies the stepped bore in the pressure regulator portion 24 of the fuel body has a recessed circuiar groove to receive an O-ring seal 56 therein for a purpose to be described.

A conventional fuel pressure regulator 57 is loosely received in the upper portion of the stepped bore in the pressure regulator portion 24 with the lower casing end 57a of the pressure regulator extending into the opening defined by lower wall 48. This portion of the pressure regulator is sealed by an O-ring seal 58 positioned so as to be in sealing abutment between the wall 47 and this lower casing end of the pressure regulator. The lower end wall of the pressure regulator 57 is provided, in known manner, with one or more apertures, not shown, whereby the interior of the regulator on one side of a diaphragm valve therein can be subjected to ambient pressure. A radial flange 57b of the pressure regulator 57 is positioned so as to abut and seal against the flat radial shoulder 50 in the fuel body 12, as biased thereagainst by the O-ring seal 56, as shown in these Figures.As shown, this O-ring seal 56 is positioned so as to encircle the outlet of the pressure regulator 57 whereby to separate this outlet from a fuel return chamber 61 to be described hereinafter.

With this arrangement, the lower casing end of the fuel pressure regulator forms with the annular wall 46 and shoulder 51 a lower fuel reservoir chamber 60 and its upper cover end forms with a portion of wall 45 and the lower surface of the fuel body cover 14 outboard of seal 56 an upper fuel return chamber 61.

In the fuel pressure regulator 57, which is preferably a conventional calibrated spring biased diaphragm valve type regulator, fuel enters through one or more inlet ports 62 extending through the upper cover end of the regulator housing to flow into an internal control chamber of the regulator, formed in part by a diaphragm valve 63, and flow from this control chamber out through the outlet 64 of the regulator is controlled by the diaphragm valve 63.

As shown in Figure 5, fuel at a predetermined low pressure is supplied to the fuel supply passages of the injector mechanism 11 through a vertical, threaded inlet passage 66 that extends upwardly from the free end of a depending cylindrical boss 67 to connect with one end of an inclined supply passage 68. Supply passage 68 opens into the reservoir chamber 60, preferably at the lower end of this chamber. The fuel body 12, in the construction shown, has two depending cylindrical bosses 67, one of which has the inlet passage 66 therein while the other has a fuel drain outlet passage 76, to be described. As shown, the bosses 67 are spaced apart and each is adapted to extend downwardly through spaced apart corresponding shaped apertures 69 provided for this purpose on one side of the throttle body 10, the left hand side of the throttle body with reference to Figure 1.

With the above described arrangement fluid connections can be made to both the inlet passage 66 and fuel drain outlet passage 76 externally of the throttle body injection apparatus and thus out of the path of flow through the air induction flow passage 7. However, as shown in Figures 4 and 5, the open end wall of the lower casing end 57a of the pressure regulator 57 would be subjected to air pressure in the flow passage 7 upstream of the throttle body 10, since this end of the regulator is elevated above the upper surface of the throttle body and is positioned in a lower recessed opening in the fuel body 12.

Inlet passage 66 is adapted to be connected by a supply conduit, not shown, to a source of fuel, as previously described, supplied at a low pressure of, for example, 420 g/cm2-1 055 g/cm2. At such a low supply pressure, the fuel can be delivered by a conventional low pressure intank fuel pump, not shown. Fuel supplied to the fuel reservoir chamber 60 is delivered to each of the supply wells 41 through a substantially horizontai fuel supply passage 70 in each of the support legs 26. Each such supply passage 70 extends from the reservoir chamber 60 through the lower portion of its associated support leg 26 (Figure 4) to open at its other end into its associated fuel well 41, to supply fuel to the associated fuel injector 30.As shown in Figures 2 and 4, each supply passage 70 is located in its associated support leg 26 so that it extends into the associated injector holder portion 25 so as substantially to intersect the shoulders 37 and 37a and thus extend through adjacent portions of walls 32 and 33 thereby provide an open fluid connection between the lower supply well 41 and the upper drain well 42. Thus any vapours that may be present in the fuel in the supply well 41 can rise upwards into the drain well 42 so that the fuel still in the well 41 that is used to supply fuel to the associated injector 30 will be substantially free of vapours.

Fuel is supplied to a fuel supply well 41 in an amount in excess of that discharged by the associated electromagnetic fuel injector 30 into the associated throttle bore 20 for induction with air into the intake manifold of the engine. This excess fuel supplied to the supply well 41 is returned in a manner to be described to the fuel tank, not shown, for the engine.

To effect this return of excess fuel, a fuel supply well 41, in accordance with the invention, is in direct flow communication with the respective upper drain well 42 in the manner described above. The drain well 42, in turn, is in fluid communication with an inclined drain passage 71 (Figure 4) that extends from an associated drain well 42 through an associated support leg 26 to open at its other end into the return chamber 61 (Figures 3 and 4) encircling the inverted cup-shaped cover of the fuel pressure regulator 57 (Figures 4 and 5). As shown in Figures 4 and 3, each drain passage 71 extending through a support leg 26 is formed in part by an inclined bore through the respective support leg and in part by the lower planar surface of the fuel body cover 14 next adjacent to the portion thereof that extends over the pressure regulator portion 24 of the fuel body 12.Fuel in the return chamber 61 then flows through the inlet ports 62 of the regulator 57 into the internal chamber thereof, the fuel then flowing out through the outlet 64 of the regulator as controlled by the spring biased diaphragm valve assembly 63 of the regulator.

Outlet 64 (Figure 4) of the pressure regulator 57, is in flow communication with a vertical drain passage 72 (Figure 5) in the fuel body cover 14 that extends from the lower surface thereof to intersect a horizontal passage 73 also provided in the fuel body cover. One end of passage 73 connects with a vertical passage 74 in the cover 14 which is coaxially aligned with a vertical passage 75 in the fuel body 12 that communicates with the axially aligned vertical threaded drain outlet passage 76. A return conduit, not shown, is connectable to the drain outlet passage 76 for returning fuel to the fuel tank, not shown, which contains fuel at substantially atmospheric pressure.

In operation, fuel, such as petrol, at a low predetermined supply pressure, preferably in the range of 420 g/cm2-1 055 g/cm2, is delivered to the injector mechanism 11 through the inlet passage 66 for flow through the reservoir chamber 60 and a supply passage 70 to the associated annular fuel supply well 41 that encircles the lower inlet end of the associated electromagnetic fuel injectors 30. Fuel entering each supply well 41 should have sufficient residence time in the fuel well, by proper sizing of the well relative to the rate of fuel flow, to enable any vapours that may be trapped in the fuel to separate therefrom and rise into the associated upper drain well 42 to be carried by excess fuel flowing from the drain well 42 back to the fuel tank for the engine.In this manner, substantially only liquid fuel flows into each fuel injector 30 so as to permit accurate fuel metering by the metering land thereof, not shown, during operation of the fuel injector.

Fuel vapour returnedto the fuel tank, not shown, as carried by the excess fuel returned to this tank, may then be removed by any of the known fuel vapour recovery or evaporative emission control systems presently used in modern day automotive vehicles. In one such system, a vapour storage canister is used to receive and store fuel vapours emitted from the fuel tank for the vehicle engine. During engine operation, the fuel vapor stored in such a canister is then purged, at a controlled rate, into the induction system of the engine so that these fuel vapours can be consumed therein.

The exterior of the fuel body 12 and its cover 14 are properly aerodynamically shaped, as desired, so as to permit smooth air flow thereover whereby the air is in thermal heat exchange relationship therewith to effect cooling of the injector mechanism 11 and of the fuel therein.

Thus, the support legs 26 together with the portions of the fuel body cover that overlie these legs are preferably elliptical or egg-shape when viewed in cross-section.

As shown in Figures 2 and 3, the fuel body 12 and its complementary fuel body cover 14, in the construction illustrated, are of substantially open V-shaped configuration. However, it will be apparent that other suitable open configurations can be used. Such open configurations are used so as to permit good heat transfer from the injector mechanism to the air flow through the induction air flow passage 7 and also so as not unduly to restrict or reduce the cross-sectional air flow area of this passage.

It will also be apparent to those skilled in the art that if desired, the injector mechanism 11 in accordance with the invention can be constructed so as to support only one fuel injector 30 for use with a throttle body having a single throttle bore therein, as for example, for use on a 4 cylinder engine.

The fuel flow to the injector mechanism 11 of the throttle body injection apparatus 5, constructed in accordance with the invention, may be any suitable amount desired whereby sufficient excess fuel is available to effect proper fuel vapour purge and to effect adequate cooling of the injector mechanism 11 and of the injectors 30 therein whereby substantially to reduce the formation of fuel vapours therein. For example, in a particular construction of a throttle body apparatus 5, as shown in Figures 1 to 5, for use with a relatively large 5.7 litre V8 engine, the fuel flow rate of the injector mechanism 11 was in the range of, for example, 114 to 1 70 litres per hour.

With a throttle body injection apparatus for use with a smaller size engine with the injector mechanism having a single fuel injector for the discharge of fuel only into the bore of a single bore throttle body, the fuel delivery to such an apparatus could be reduced so that the fuel flow is in the range of, for example, 57 to 114 litres per hour. In both of the above examples, the amount of fuel injected is less than the amount delivered to the injector mechanism of the throttle body injection apparatus whereby sufficient fuel is available to effect cooling of the injector mechanism 11 and of the fuel injectors 30, with excess fuel being returned to the fuel tank, not shown, to mix with the fuel stored in the fuel tank.

The interconnected lower supply well 41 and upper drain well 42 surrounding an associated fuel injector mechanism 11 permits direct purging of any vapours from the fuel in fuel well 41 before it flows into the fuel injector. This is effected by permitting the vapours from the fuel into the fuel well 41 to rise into the drain well 42 for removal by the flow of excess fuel flowing therefrom out through the associated drain passage 71. In addition, since two associated wells 41 and 42 encircle the exterior of the associated fuel injector 30 with the fuel in these wells in thermal contact over a substantial length of the fuel injector 30, a more effective cooling of the fuel injector will occur thereby reducing the possibility of vapour generation in the fuel injector.Thus, if each fuel injector 30 is supplied with and has only liquid fuel with substantially no vapour therein, fuel metering will remain uniform. That is, fuel metering within the injector will not be effected by any substantial amounts of vapour during engine operation.

It will be apparent to those skilled in the art that various modifications can be made to the subject injector mechanism without departing from the scope of the invention. For example, although a particular fluid interconnection between the fuel supply well 41 and the fuel drain well 42 has been described and illustrated with reference to a preferred embodiment, it will be apparent that this connection could be accomplished by other means. As an example, a recessed groove, not shown could be formed in the flat shoulder 37a to provide for fluid communication between the supply well 41 and the drain well 42. Preferably, this groove, not shown, should be provided at a location diametrically opposite the associated fuel supply passage, such as passage 70, used to supply fuel to the supply well 41. By this arrangement, excess fuel supplied to the fuel well 41 would be required to flow circumferentially around opposite sides of the associated injector 30 before excess fuel and vapour could flow from the supply well 41 to its associated drain well 42.

Claims (2)

Claims

1. An injector mechanism for use with a throttle body in a low pressure throttle body injection apparatus for an internal combustion engine, the throttle body having at least one throttle bore therethrough with a movable throttle valve therein controlling flow therethrough; said injector mechanism comprising a housing having a pressure regulator portion, at least one injector holder portion and at least one support leg interconnecting said pressure regulator portion to said injector holder portion; an open-ended injector socket in said injector holder portion; mounting means on said housing for fixing said housing on said throttle body with said socket positioned above, concentric with, and opening at one end toward the throttle bore; a fuel injector positioned in said socket, said fuel injector forming with said socket an annular fuel supply well, and a drain well above and in communication with-saidfuel well said fuel injector having a spray tip end at its lower end positioned to discharge fuel into the throttle bore and lateral inlet passages closely adjacent said spray tip end in flow communication with said fuel supply well, said fuel pressure regulator portion having a fuel inlet passage connectable to a source of low pressure fuel and fuel return passage connectable to a reservoir for fuel at substantially atmospheric pressure, said fuel inlet passage including a supply passage extending through said support leg and in flow communication with said fuel supply well adjacent said lateral inlet passages, said fuel return passage including a drain passage which extends through said support leg and is arranged above said supply passage from said fuel drain well so as to enable fuel vapour in said fuel supply well to rise to said drain chamber for discharge out through said drain passage.

2. An injector mechanism for use with a throttle body in a low pressure throttle body injection apparatus for an internal combustion engine constructed and adapted to operate substantially as hereinbefore described with reference to and as shown in the accompanying drawings.