FUEL INJECTION APPARATUS

Abstract: In a fuel injection apparatus for a multi-cylinder internal combustion engine (2l), a plurality of injection nozzles (l4) discharge fuel adjacent the engine inlet ports (l8), and a single fuel injector (l0) meters the fuel to all of the injection nozzles. The fuel injector (l0) comprises an injector base (28) having a plurality of fuel discharge passages (34) and an annular region (32) through which fuel is delivered to the fuel discharge passages, each of the fuel discharge passages being adaptable to direct fuel to one of the injection nozzles, the annular region including a valve surface (48), a single valve member (30) associated with the valve surface, the valve member being adapted to engage the valve surface to preclude fuel delivery to the fuel discharge passages, a solenoid (52) adapted to disengage the valve member from the valve surface to permit fuel delivery to the fuel discharge passages, characterised by air valve means (58, 64, 66) for controlling flow of air to the fuel discharge passages (34) and being adapted to preclude air flow to the fuel discharge passages when the valve member permits fuel delivery to the fuel discharge passages and to admit air to the fuel discharge passages when the valve member precludes fuel delivery to the fuel discharge passages.

Description: This invention relates to a fuel injection apparatus for a multi-cylinder internal combustion engine in which a plurality of injection nozzles discharge fuel adjacent the inlet ports of the engine and a single fuel injector meters the fuel to all of the injection nozzles, as, for example, disclosed in US-A-4,570,598. Current automotive engine fuel injection apparatus employ electromagnetic fuel injectors to meter and deliver the fuel to the engine. Throttle body fuel injection apparatus employ one or two fuel injectors that deliver the fuel into the air flowing through the engine throttle body, and the mixture of air and fuel then flows through the engine inlet manifold to the inlet ports of the engine combustion chambers. Port fuel injection apparatus on the other hand, typically employ individual fuel injectors to deliver fuel directly to each of the inlet ports. A throttle body fuel injection apparatus with only one or two fuel injectors has a cost advantage over a port fuel injection apparatus with its several fuel injectors and the associated fuel rails. However, port fuel injection apparatus offer advantages in engine operation. Those comparative advantages present incentive for a fuel injection apparatus in which a single fuel injector meters fuel and a plurality of injection nozzles deliver the fuel to the engine inlet ports. This invention permits a fuel injection apparatus to deliver fuel through a plurality of injection nozzles directly to the inlet ports and to employ a single fuel injector to meter the fuel to all of the injection nozzles. A fuel injector in accordance with the present invention is characterised over US-A-4,570,598 by the features specified in the characterising portion of Claim 1. With reference to GB-A-2188982; DE-A-3710127; and FR-A-2597158, the Applicant has voluntarily limited the scope of the present application and submitted separate claims for Gt. Britain, Germany and France. According to one feature of this invention, a single fuel injector meters fuel through an annular region into a cylindrical chamber defined between a bore in the injector base and a plug received in the bore, and a plurality of fuel discharge passages open from the cylindrical chamber to direct fuel to injection nozzles. With this feature, a solenoid operated valve in the fuel injector may meter fuel to the fuel discharge passages with very little motion. According to another feature of this invention, a fuel injector meters fuel through an annular region to a plurality of fuel discharge passages that direct the fuel to injection nozzles, and the fuel injector includes a valve member with an aperture opening into the centre of the annular region. With this feature, fuel flows to the annular region both around the valve member and through the aperture when the valve member is lifted from its valve seat. This feature accordingly further reduces the motion of the valve member that is required to meter fuel to the fuel discharge passages. According to yet another feature of this invention, a single fuel injector meters fuel to a plurality of fuel discharge passages that direct the fuel to injection nozzles, and a rectifier valve allows air to flow into the fuel discharge passages when the fuel injector is not metering fuel into the fuel discharge passages. With this feature, the fuel maintains its discharge velocity through the fuel discharge passages to the injection nozzles. This feature also reduces the propagation of pressure waves through the fuel discharge passages as the fuel injector initiates and terminates fuel flow into the fuel discharge passages. According to a further feature of this invention, a fuel injector has a base with a plurality of fuel discharge passages that receive the ends of fuel discharge lines through which fuel is directed to injection nozzles, the injector base has an air inlet surrounding the ends of the fuel discharge lines, and air lines surround the fuel discharge lines and direct air to the injection nozzles. With this feature, the fuel discharge lines are thermally insulated. This invention is now described, by way of example of several embodiments, which are set forth in the following description and the accompanying drawings, in which:- Figure l is a schematic view of fuel injection apparatus having a single fuel injector that meters fuel to six injection nozzles in accordance with this invention; Figure 2 is an enlarged sectional view of the fuel injector of Figure l, showing a valve member which is solenoid operated and which meters fuel through sectors of a cylindrical fuel distribution chamber to fuel discharge passages and fuel discharge lines that lead to the injection nozzles, a rectifier valve disc that admits air through the sectors to the fuel discharge passages and fuel discharge lines, and an air inlet for air lines that surround the fuel discharge lines; Figure 3 is a view, indicated by the line 3-3 of Figure 2, of the fuel inlet side of the injector base of the fuel injector; Figure 4 is an enlarged sectional view of the tip of the injection nozzles of Figure 1; Figure 5 is a view, indicated by the line 5-5 of Figure 4, of an insert for the injection nozzles, showing the insert before its installation in the injection nozzle; Figure 6 is an enlarged end view of the injection nozzles of Figure 1; Figure 7 is an enlarged sectional view of another fuel injector that meters fuel to six injection nozzles in accordance with this invention; in this fuel injector a pair of (solenoid operated) valve members meter fuel and air directly to fuel discharge passages and fuel discharge lines that lead to the injection nozzles; Figure 8 is a view indicated by the line 12-12 of Figure 7, showing the fuel inlet side of the injector base of the fuel injector of Figure 7; Figure 9 is a view, indicated by the line 13-13 of Figure 7, showing the air inlet side of the injector base of the fuel injector of Figure 17; Figure 10 is a schematic view of yet another fuel injection apparatus having a single fuel injector that meters fuel to six injection nozzles in accordance with this invention; Figure 11 is an enlarged sectional view of the fuel injector of Figure 10 showing a (solenoid operated) valve member that meters fuel directly to fuel discharge passages and fuel discharge lines that lead to the injection nozzles; Figure 12 is an enlarged sectional view of the injection nozzles of Figure 10; and Figure 13 is an enlarged sectional view of another tip for the injection nozzle of Figure 1. Referring first to the fuel injection apparatus of Figures l through 6, a single fuel injector l0 receives fuel from a source of fuel at a desired pressure and meters fuel into six fuel discharge lines l2. Each fuel discharge line l2 leads to an injection nozzle l4 that delivers the metered fuel into the stream of air flowing through one of the inlet manifold runners l6 and one of the inlet ports l8 to one of the combustion chambers 20 of a six cylinder engine 2l. Fuel injector l0 has a housing 22 with a fuel inlet port 24 and an excess fuel outlet port 26 that establish a path for fuel flow through housing 22. Housing 22 is secured to an injector base 28. A valve member 30 which is solenoid operated controls fuel flow from housing 22 through an annular region 32 of injector base 28 to six fuel discharge passages 34 that receive fuel discharge lines l2. Injector base 28 has a central bore 36 and includes a plug 38 received in central bore 36 to define a cylindrical fuel distribution chamber 40 between plug 38 and central bore 36. The upper portion of plug 38 has a hexagonal configuration, the points 44 of which engage central bore 36 to divide cylindrical fuel distribution chamber 40 into six sectors 46. Each sector 46 opens into one of the fuel discharge passages 34. The surface 48a surrounding central bore 36 and the surface 48b at the perimeter of plug 38 form an annular valve surface bounding annular region 32. A spring 50 biases valve member 30 into engagement with surfaces 48a,b to interrupt fuel flow through annular region 32. When energized, a solenoid coil 52 lifts valve member 30 against the bias of spring 50 to permit fuel flow through annular region 32 and the sectors 46 of cylindrical fuel distribution chamber 40 to fuel discharge passages 34 and fuel discharge lines l2. When valve member 30 is lifted from surfaces 48a,b, fuel flows through a cylindrical area between valve member 30 and surface 48a. That cylindrical area is determined both by the radius of central bore 36 and by the height to which valve member 30 is lifted above surfaces 48a,b. As the radius of central bore 36 is increased, the height to which valve member 30 must be lifted may be decreased without restricting fuel flow into annular region 32. By using plug 38 to form the fuel flow region as an annular region 32 and to form the fuel distribution chamber as a cylindrical fuel distribution chamber 40, the radius is increased without increasing the desired area for the fuel flow region and the desired volume for the fuel distribution chamber. The use of an annular fuel flow region accordingly reduces the motion of the valve member 30 as it is lifted by solenoid coil 52. To further reduce the motion of valve member 30 as it is lifted by solenoid coil 52, valve member 30 has an aperture 54 opening from housing 22 to a space 56 beneath valve member 30 within surface 48b. Thus when valve member 30 is lifted by solenoid coil 52, fuel flows into annular region 32 both around valve member 30 and through aperture 54 and space 56. It will be understood, therefore, that the clearance required between valve member 30 and surface 48a is less with aperture 54 providing a path for fuel flow between valve member 30 and surface 48b into annular region 32 than would be required if it were necessary for all fuel flow into annular region 32 to pass around valve member 30 and between valve member 30 and surface 48a. Fuel injector l0 is controlled to meter fuel in a conventional manner by energizing solenoid coil 52 with a pulse width modulated current. As the pulse width is increased, valve member 30 is lifted for an increased length of time to increase the duration of fuel flow into fuel discharge lines l2. Plug 38 has a recess 58 open to the atmosphere and six ports 60 opening slightly downwardly from recess 58 into the sectors 46 of cylindrical fuel distribution chamber 40. A hollow valve seat member 62 is received in recess 58 and has a valve seat 64 which is upwardly facing. A rectifier valve disc 66 of lightweight Mylar rests on valve seat 64. Recess 58, valve seat 64 and rectifier valve disc 66 define air valve means. Injector base 28 has a larger recess 68 open to the atmosphere and six air passages 70 surrounding fuel discharge lines l2. Air passages 70 receive air lines 72 that are disposed concentrically about fuel discharge lines l2. Further details of the construction of fuel injector l0 are set forth in US patent 4572436 and will not be repeated here. Fuel discharge lines l2 and air lines 72 terminate in injection nozzles l4. Each injection nozzle l4 has a fluted insert 74 with a tapered tip 76 engaged in the end of fuel discharge line l2 and a tapered base 78 engaged in the end of air line 72. Fluted insert 74 aligns fuel discharge line l2 within air line 72, and its flutes 80 deliver the fuel and air into the stream of air flowing through the inlet manifold runner l6. In operation, the atmospheric pressure in larger recess 68 induces air to flow through air lines 72 to the subatmospheric pressure in the inlet ports l8, and the atmospheric pressure in recess 58 induces air to flow past rectifier valve disc 66 and through ports 60, sectors 46 of cylindrical fuel distribution chamber 40, and fuel discharge passages 34 and fuel discharge lines l2 to the subatmospheric pressure in inlet ports l8. When solenoid coil 52 lifts valve member 30 and fuel flows through annular region 32 into the sectors 46 of cylindrical fuel distribution chamber 40, the increased pressure in cylindrical fuel distribution chamber 40 stops air flow through ports 60 from recess 58 and engages rectifier valve disc 66 with its valve seat 64. When solenoid coil 52 is deenergized and spring 50 engages valve member 30 against surfaces 48a,b, air will again be induced to flow from recess 58 past rectifier valve disc 66 and through ports 60, sectors 46 of cylindrical fuel distribution chamber 40, and fuel discharge passages 34 and fuel discharge lines l2. Air flow through the sectors 46 of cylindrical fuel distribution chamber 40 and the fuel discharge passages 34 and fuel discharge lines l2 allows the inertia of the fuel to maintain its discharge velocity, and reduces propagation of pressure waves through fuel discharge lines l2 as valve member 30 is lifted from and engaged with surfaces 48a,b. Such air flow also provides a source of air at substantially atmospheric pressure immediately below valve member 30, thereby providing an essentially constant pressure in the annular region 32 to which valve member 30 delivers fuel. Fuel discharge passages 34 open from the bottom of sectors 46, while ports 60 open slightly downwardly into the upper portion of sectors 46. With this construction, it is thought that fuel flow through sectors 46 past ports 60 will create a suction tending to assist in quickly lifting rectifier valve disc 66 from its valve seat 64. Air flow through air lines 72 thermally insulates fuel discharge lines l2, and provides a source of air at substantially atmospheric pressure at the tip of injection nozzles l4 where the fuel is introduced into the stream of air flowing through the inlet ports l8. In the particular application for which this embodiment of the invention was developed, injection nozzle l4 is proportioned so that the vacuum in a zone 82 within air line 72 at the end of fuel discharge line l2 is about l0% of the vacuum in the intake port l8 at the end of the injection nozzle l4 (that is, the difference between the pressure in zone 82 and the atmospheric pressure is about l0% of the difference between the pressure in intake port l8 and the atmospheric pressure). In that same application, fuel discharge line l2 is formed of tubing with a 0.864mm (0.034in) inside diameter and a l.60 mm (0.063in) outside diameter, and air line 72 is formed of tubing with a 2.36mm (0.093in) inside diameter and a 3.00mm (0.ll8in) outside diameter. Other parts are sized accordingly. Referring to the fuel injector of Figures 7 through 9, a single fuel injector 310 receives fuel from a source of fuel at a desired pressure and meters fuel into six fuel discharge lines 312. Each fuel discharge line 3l2 leads to an injection nozzle that delivers the metered fuel into the stream of air flowing through one of the inlet manifold runners and one of the inlet ports to one of the combustion chambers of a six cylinder engine. Fuel injector 3l0 has a housing 322a with a fuel inlet port 324a and an excess fuel outlet port that establish a path for fuel flow through housing 322a. Housing 322a is secured to an injector base 328. A valve member 330a which is solenoid operated controls fuel flow from housing 322a through an annular region 332a of injector base 328 to six fuel discharge passages 334a that extend to fuel discharge lines 3l2. Annular region 332a includes a surface 348a. A spring 350a biases valve member 330a into engagement with surface 348a to interrupt fuel flow through annular region 332a. When energized, a solenoid coil 352a lifts or retracts valve member 330a against the bias of spring 350a to permit fuel flow through annular region 332a to fuel discharge passages 334a and fuel discharge lines 3l2. Fuel injector 3l0 also has a housing 322b with an air inlet port 324b. Housing 322b is secured to injector base 328. A valve member 330b which is solenoid operated controls air flow from housing 322b through an annular region 332b of injector base 328 to six air discharge passages 334b that extend to fuel discharge lines 3l2. Annular region 332b includes a surface 348b. A spring 350b biases valve member 330b into engagement with surface 348b to interrupt air flow through annular region 332b. When energized, a solenoid coil 352b retracts valve member 330b against the bias of spring 350b to permit air flow through annular region 332b to air discharge passages 334b and fuel discharge lines 3l2. Annular region 332b, surface 348b, valve member 330b and solenoid coil 352b define air valve means. To reduce the motion of valve members 330a,b as they are retracted by solenoid coils 352a,b, valve members 330a,b have apertures 354a,b opening from housings 322a,b to the centre of annular regions 332a,b. Thus when valve members 330a,b, are retracted by solenoid coils 352a,b, fuel and air flow into annular regions 332a,b both around valve members 330a,b and through apertures 354a,b. It will be understood, therefore, that the clearance required between valve members 330a,b and surfaces 348a,b is less with apertures 354a,b providing paths for fuel and air flow between valve members 330a,b and surfaces 348a,b into annular regions 332a,b than would be required if it were necessary for all fuel and air flow into annular regions 332a,b to pass around valve members 330a,b. Fuel injector 3l0 is in other respects similar to fuel injector l0, and further details of construction are set forth in US patent 4572436 and will not be repeated here. In operation, solenoid coils 352a,b are energized alternately. When solenoid coil 352b is energized, the pressure in housing 322b induces air to flow through air discharge passages 334b and fuel discharge lines 3l2 to the subatmospheric pressure in the inlet ports. When solenoid coil 352a is energized, fuel flows through annular region 332a to fuel discharge passages 334a and fuel discharge lines 3l2. Air flow through the fuel discharge lines 3l2 allows the inertia of the fuel to maintain its discharge velocity, and reduces propagation of pressure waves through fuel discharge lines 3l2 as valve member 330a is lifted from and engaged with surface 348a. Such air flow also creates an essentially constant pressure in the annular region 332a to which valve member 330a delivers fuel. Referring to the fuel injection apparatus of Figures 10 through 12, a single fuel injector 6l0 receives fuel from a source of fuel at a desired pressure and meters fuel into six fuel discharge lines 6l2. Each fuel discharge line 6l2 leads to an injection nozzle 6l4 that delivers the metered fuel into the stream of air flowing through one of the inlet manifold runners 6l6 and one of the inlet ports 6l8 to one of the combustion chambers 620 of a six cylinder engine 62l. Fuel injector 6l0 has a housing 622 with a fuel inlet port 624 and an excess fuel outlet port 626 that establish a path for fuel flow through housing 622. Housing 622 is secured to an injector base 628. A valve member 630 which is solenoid operated controls fuel flow from housing 622 through an annular region 632 of injector base 628 to six fuel discharge passages 634 that extend to fuel discharge lines 6l2. Annular region 632 includes a surface 648. A spring 650 biases valve member 630 into engagement with surface 648 to interrupt fuel flow through annular region 632. When energized, a solenoid coil 652 lifts valve member 630 against the bias of spring 650 to permit fuel flow through annular region 632 to fuel discharge passages 634 and fuel discharge lines 6l2. To reduce the motion of valve member 630 as it is lifted by solenoid coil 652, valve member 630 has an aperture 654 opening from housing 622 to the centre of annular region 632. Thus when valve member 630 is lifted by solenoid coil 652, fuel flows into annular region 632 both around valve member 630 and through aperture 654. It will be understood, therefore, that the clearance required between valve member 630 and surface 648 is less with aperture 654 providing a path for fuel flow between valve member 630 and surface 648 into annular region 632 than would be required if it were necessary for all fuel flow into annular region 632 to pass around valve member 630 and between valve member 630 and surface 648. Fuel injector 6l0 is in other respects similar to fuel injector l0, and further details of construction are set forth in US patent 4572436 and will not be repeated here. Each fuel discharge line 6l2 terminates in an orifice 679 in an injection nozzle 6l4. Each injection nozzle 6l4 has an air line 672 opening from the atmosphere and terminating in an orifice 68l. Injection nozzles 6l4 deliver the fuel and air into the stream of air flowing through the inlet ports 6l8. In operation, the atmospheric pressure induces air to flow through air lines 672 to the subatmospheric pressure in the inlet ports 6l8. When solenoid coil 652 is energized, fuel flows through annular region 632 to fuel discharge passages 634 and fuel discharge lines 6l2. Air flow through air lines 672 provides a source of air at substantially atmospheric pressure at the tip of injector nozzles 6l4 where the fuel is introduced into the stream of air flowing through the inlet ports 6l8. Referring to the injection nozzle of Figure 13, fuel discharge line 7l2 and air line 772 terminate in injection nozzle 7l4. To form injection nozzle 7l4, the open end 775 of each air line 772 is reduced, and the open end of each fuel line 7l2 is spaced from the open end 775 of the associated air line 772. Each fuel line 7l2 is formed with a helically coiled section 783 that embraces the inner wall 785 of the associated air line 772 to support the fuel discharge line 7l2 within the air line 772. In the particular application for which this embodiment of the invention was developed, fuel discharge line 7l2 is formed of tubing with a 0.864mm (0.034in) inside diameter and a l.57mm (0.062in) outside diameter, air line 772 is formed of tubing with a 3.05mm (0.l20in) inside diameter and a 3.96mm (0.l56in) outside diameter, and the helically coiled section 783 has a free overall diameter of at least 3.l8mm (0.l25in) to assure that it will be compressively engaged with the inside wall 785 of the air line 772. The open end 775 of each air line 772 is reduced to an inside diameter of l.4mm (0.055in) over a length of l.02mm (0.04in), and the spacing between the end of the fuel discharge line 7l2 and the open end 775 of the air line 772 is adjusted for the desired fuel spray characteristic. Injection nozzles 7l4 may be employed to directly replace injection nozzles l4 in the Figure l embodiment. In another embodiment, however, the fuel injector shown in figure 2 is mounted in the top of an inlet manifold plenum with the terminals for the solenoid coil projecting outside and the concentric fuel and air lines extending inside the manifold through the manifold plenum and runners to injection nozzles 7l4. Such a construction presents an improved appearance and protects the concentric fuel and air lines against damage, while still allowing injection nozzles 7l4 to deliver metered fuel into the stream of air flowing through the inlet ports to the engine combustion chambers. In such a construction, of course, an air supply line must extend from a source of clean air to the base of the fuel injector.

Claims: Claims for the following Contracting States : AT, IT A fuel injector (10, 310, 610) for metering fuel to a plurality of injection nozzles (14, 614), the fuel injector comprising a base (28, 328, 628) having a valve surface (48, 348a, 648) and a plurality of fuel discharge passage means (34, 46, 334a, 634), each of the fuel discharge passage means being adaptable to direct fuel to one of the injection nozzles, a single valve member (30, 330a, 630) associated with the valve surface, the valve member being adapted to engage the valve surface to preclude fuel delivery to the fuel discharge passage means, and a solenoid (52, 352a, 652) adapted to disengage the valve member from the valve surface to permit fuel delivery to the fuel discharge passage means, characterised in that the valve surface (48, 348a, 648) is planar, in that the fuel discharge passage means (34, 46, 334a, 634) open through the planar valve surface, and in that each of the fuel discharge passage means forms a separate and distinct passage for fuel flow from the planar valve surface to its respective injection nozzle. A fuel injector (10) as claimed in Claim 1, further comprising air valve means (58, 64, 66) for controlling flow of air to each of the fuel discharge passage means (34, 46) and being adapted to preclude air flow to the fuel discharge passage means when the valve member permits fuel delivery to the fuel discharge passage means and to admit air to the fuel discharge passage means when the valve member precludes fuel delivery to the fuel discharge passage means. A fuel injector as claimed in Claim 2, wherein the air valve means comprises an opening (58) in the injector base (28) through which air can flow to each of the fuel discharge passage means (34, 46), a valve seat (64) surrounding the opening, and a rectifier valve (66) associated with the valve seat, the rectifier valve being pressure responsive and thereby being adapted to engage the valve seat to preclude air flow through the opening when the valve member (30) permits fuel delivery to the fuel discharge passage means and to disengage the valve seat to admit air to the fuel discharge passage means when the valve member precludes fuel delivery to the fuel discharge passage means. A fuel injector as claimed in Claim 3, wherein the rectifier valve is a rectifier valve disc (66). A fuel injector as claimed in Claim 2, wherein the air valve means comprises an additional annular region (332b) in the injector base (328) through which air flows to the fuel discharge passage means, the additional annular region including an additional valve surface (348b), an additional single valve member (330b) associated with the additional valve surface, the additional valve member being adapted to engage the additional valve surface to preclude air flow to the fuel discharge passage means, and an additional solenoid (352b) adapted to disengage the additional valve member from the additional valve surface to permit air flow to the fuel discharge passage means. A fuel injector as claimed in any one of Claims 1 to 5, further comprising a plurality of fuel discharge lines (12) respectively connected at one end to the fuel discharge passage means (34) and extending to the injection nozzles (14) at the other end, wherein the injector base (32) further has an air inlet (68,70) surrounding one end of each of the fuel discharge lines, and a plurality of air lines (72) connected at one end to the air inlet and respectively surrounding the fuel discharge lines and extending to the injection nozzles at the other end. A fuel injector as claimed in any one of Claims 1 to 6, wherein the injector base (28) has a central bore (36) and includes a plug (38) received in the central bore to define a fuel distribution chamber (40) between the plug and the central bore, the valve surface (48) including a first portion (48a) surrounding the central bore and a second portion (48b) at the perimeter of the plug, the plug (38) engaging the central bore (36) at peripherally spaced locations (44) to divide the fuel distribution chamber (40) into a plurality of sectors (46), each of the fuel discharge passage means comprising one of the sectors and a fuel discharge passages (34) opening from said one of the sectors. A fuel injector as claimed in any one of Claims 1 to 7, wherein the valve member (30) has an aperture (54) opening therethrough to provide a path for fuel flow to the fuel discharge passage means (34, 46) when the valve member is disengaged from the valve surface (48). A fuel injector as claimed in any one of Claims 1 to 8, wherein the valve member (30) has a cross-section which is tapered from its outer edge to its inner edge adjacent the valve surface (48), the outer edge being thicker than the inner edge. Claims for the following Contracting States : DE, FR, GB A fuel injector (10, 310, 610) for metering fuel to a plurality of injection nozzles (14, 614), the fuel injector comprising a base (28, 328, 628) having a valve surface (48, 348a, 648) and a plurality of fuel discharge passage means (34, 46, 334a, 634), each of the fuel discharge passage means being adaptable to direct fuel to one of the injection nozzles, a single valve member (30, 330a, 630) associated with the valve surface, the valve member being adapted to engage the valve surface to preclude fuel delivery to the fuel discharge passage means, and a solenoid (52, 352a, 652) adapted to disengage the valve member from the valve surface to permit fuel delivery to the fuel discharge passage means, characterised in that the valve surface (48, 348a, 648) is planar, in that the fuel discharge passage means (34, 46, 334a, 634) open through the planar valve surface, in that each of the fuel discharge passage means forms a separate and distinct passage for fuel flow from the planar valve surface to its respective injection nozzle, and in that the valve member (30) has a cross-section which is tapered from its outer edge to its inner edge adjacent the valve surface (48), the outer edge being thicker than the inner edge. A fuel injector (10) as claimed in Claim 1, further comprising air valve means (58, 64, 66) for controlling flow of air to each of the fuel discharge passage means (34, 46) and being adapted to preclude air flow to the fuel discharge passage means when the valve member permits fuel delivery to the fuel discharge passage means and to admit air to the fuel discharge passage means when the valve member precludes fuel delivery to the fuel discharge passage means. A fuel injector as claimed in Claim 2, wherein the air valve means comprises an opening (58) in the injector base (28) through which air can flow to each of the fuel discharge passage means (34, 46), a valve seat (64) surrounding the opening, and a rectifier valve (66) associated with the valve seat, the rectifier valve being pressure responsive and thereby being adapted to engage the valve seat to preclude air flow through the opening when the valve member (30) permits fuel delivery to the fuel discharge passage means and to disengage the valve seat to admit air to the fuel discharge passage means when the valve member precludes fuel delivery to the fuel discharge passage means. A fuel injector as claimed in Claim 3, wherein the rectifier valve is a rectifier valve disc (66). A fuel injector as claimed in Claim 2, wherein the air valve means comprises an additional annular region (332b) in the injector base (328) through which air flows to the fuel discharge passage means, the additional annular region including an additional valve surface (348b), an additional single valve member (330b) associated with the additional valve surface, the additional valve member being adapted to engage the additional valve surface to preclude air flow to the fuel discharge passage means, and an additional solenoid (352b) adapted to disengage the additional valve member from the additional valve surface to permit air flow to the fuel discharge passage means. A fuel injector as claimed in any one of Claims 1 to 5, further comprising a plurality of fuel discharge lines (12) respectively connected at one end to the fuel discharge passage means (34) and extending to the injection nozzles (14) at the other end, wherein the injector base (32) further has an air inlet (68,70) surrounding one end of each of the fuel discharge lines, and a plurality of air lines (72) connected at one end to the air inlet and respectively surrounding the fuel discharge lines and extending to the injection nozzles at the other end. A fuel injector as claimed in any one of Claims 1 to 6, wherein the injector base (28) has a central bore (36) and includes a plug (38) received in the central bore to define a fuel distribution chamber (40) between the plug and the central bore, the valve surface (48) including a first portion (48a) surrounding the central bore and a second portion (48b) at the perimeter of the plug, the plug (38) engaging the central bore (36) at peripherally spaced locations (44) to divide the fuel distribution chamber (40) into a plurality of sectors (46), each of the fuel discharge passage means comprising one of the sectors and a fuel discharge passages (34) opening from said one of the sectors. A fuel injector as claimed in any one of Claims 1 to 7, wherein the valve member (30) has an aperture (54) opening therethrough to provide a path for fuel flow to the fuel discharge passage means (34, 46) when the valve member is disengaged from the valve surface (48).

Inventors: STETTNER, ERNEST RICHARD, STOLTMAN, DONALD DIBBLE
Applicants: GENERAL MOTORS CORPORATION
Application year: 1987
Main classification: F02M69
IPC codes: F02M51, F02M69