GB1592171A - Fuel system for an internal combustion engine - Google Patents

Description

(54) FUSEL SYSTEM FOR AN INTERNA L COMBUSTION ENGINE (71) We, LUCAS INDUSTRIES LIMITED, a British Company, of Great King Street, Birmingham B19 2XF, England, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly descrilbed in and by the following statement: This invention relates to a fuel system for an internal combustion engine particularly, though not exclusively, for a compression ignition engine.

According to the present invention there is provided a fuel system for an internal combustion engine, comprising a fuel injection device; a fuel injection pump having an outlet through which fuel at high pressure is delivered to said injection device by means of a high pressure line; and means connecting the high pressure line to the fuel pump outlet, said connec.ting means including a body having an axial bore therein, the body being in screw-threaded engagement with the fuel injection pump and the bore being in communication with said outlet, a side drilling communicating with said bore through which fuel passes to the high pressure line in use, and valve means including a valve member which is manually adjustable relative to said body so as to vent said bore to atmosphere.

Preferably, the valve means includes a seat defined by a step in the bore and a portion which co-operates with the seat, adjustment of the valve member relative to the ibody in use enabling said portion to move into and out of engagement with the seat.

Conveniently, said portion of the valve means comprises a ball which is accommodated between the seat and the valve member.

Desirably, the valve member is in screwthreaded engagement with the body, the valve member being adjusted in use by rotation relative to the body.

Advantageously, the body includes a screw-threaded portion which engages the fuel pump, an abutment portion spaced from the screw-threaded portion, said side drilling being disposed between said abutment portion and said screw threaded portion, said side drilling being disposed between said abutment portion and screw threaded portion, and the connecting means further includes a connection member connected to the high pressure line and clamped between the fuel pump and the abutment portion of the body, said connection member having a bore therein which communicates with the side drilling in the body.

Most advantageously, the connection member has an aperture therein through which the Ibody passes, the 'bore in the connection member communicating with the aperture.

A further side drilling which communicates with the atmosphere may be provided in the body, and the valve member controls communication Ibetween the further side drilling and the bore. The further side drilling is preferably provided in the abutment portion of the body.

Embodiments of the present invention will now be described by way of example, with reference to the accompanying drawings, in which: Figure 1 is a schematic diagram of a fuel system according to the present invention for a compression ignition engine; Figure 2 is a sectional side view of a first embodiment of part of the fuel system of Figure 1; Figure 3 is a sectional side view of a second embodiment of part of the fuel system of Figure 1; and Figure 4 is a sectional side view of a third embodiment of part of the fuel system of Figure 1.

Referring first to Figure 1, the fuel system shown therein comprises generally a fuel tank 10, a fuel injection pump 11, and a feed pump 12 for feeding fuel from the tank 10 to the fuel pump 11 at a comparatively low pressure. A sedimenter 13, which may optionally contain a fuel cut-off device, is provided between the tank 10 and the feed pump 12, and a combined filter and agglomerator 14 is provided between the feed pump 12 and the fuel pump 11. Excess fuel from the pump 11 is returned to the tank 10 via a return line 15. The arrangement thus far described is entirely conventional.

The fuel injection pump 11 is of the distributor type and has a plurality of outlets through each of which fuel is delivered at high pressure to a respective fuel injection device 17 (only one shown) via a respective high pressure line 18. The fuel injection devices are mounted on a compression ignition engine in a conventional manner. The fuel pump 11 has a first manually operable valve 19 by which the low pressure side of the pump can be vented to atmosphere, and a second manually operable valve 20 by which the high pressure side of the pump can be vented to atmosphere. The second valve 20 forms part of connecting means to be described later whereby one of the high pressure lines 18 is connected to the respective outlet of the fuel pump 11.

The fuel system also comprises a manually operable priming pump 22 connected between the sedimenter 13 and the feed pump 12. The valve 19 on the low pressure side of the fuel pump 11 is opened initially and the pump 22 is manually operated until fuel free from air emerges from the valve 19. Valve 19 is then closed and valve 20 is opened, and the engine is cranked until it fires, whereupon valve 20 is closed.

As mentioned above, the valve 20 forms part of connecting means whereby one of the high pressure lines is connected to the respective outlet of the fuel pump 11. A first embodiment of such connecting means is shown in Figure 2, in which the outlet from the fuel pump 11 is designated generally at 25. The connecting means includes a connection member 26 of the so-called "banjo" type which is secured to an end of the high pressure line (not shown). The member 26 has an aperture 27 therethrough and a bore 28 therein which provides communication between the aperture 27 and the high pressure line.

The connecting means also includes a boltlike body 29 having a screw-threaded portion 30 which is engaged with corresponding screw-threading on the outlet 25, and a head 31 which is spaced from the screw-threaded portion 30 by an intermediate portion 32.

The body 29 passes through the aperture 27, and the connection member 26 is clamped between the fuel pump 11 and the head 31 of body 29. A pair of sealing washers 33 are provided between the fuel pump 11 and the connection member 26, and between the connection member 26 and the head 31, respectively.

A bore 35 extends axially through the bodv 29, and the intermediate portion 32 of the body 29 has four side drillings 36 therein arranged in diametrically opposed pairs which are mutually staggered, and which communicate with the bore 35. The intermediate portion 32 is so sized relative to the aperture 27 in the connection member 26 that an annular passage 37 is created between the portion 32 and the member 26, and goth the side drillings 36 and the bore 28 in the connection member 26 communicate wtth this passage.

The aforementioned valve 20 is provided at an end of the body 29 remote from the screw-threaded portion 30, and controls communication between the bore 35 and a side drilling 39 provided in the head 31, which side drilling 39 communicates with atmosphere. The valve 20 comprises a seat 40 defined by an axial step in the bore 35, a ball 41 which is engageable with the seat 40, and a valve member 42 in screw-threaded engagement with the body 29. The ball 41 is accommodated between the valve member 42 and the seat 40. Rotation of the valve member 42 relative to the body 29 causes the valve member to move towards and away from the seat 40, thereby enabling the ball 41 to move into and out of engagement with the seat.Movement of the valve member 42 away from the seat 40 is limited by a bent-over portion 43 of the body 29, which also serves to hold the valve member 42 captive in the body 29. A tommy bar 44 extends through an aperture in the free end of the valve member 42 so as to facilitate manual rotation of the latter. The tommy bar 44 can be detached from the valve member 42 when desired.

When the elements of the connecting means are in the positions illustrated, fuel at pressure emerging from the fuel pump outlet 25 passes to the high pressure line via the bore 35, side drillings 36, passage 37 and bore 28. This is because the valve member 42 holds the ball 41 in tight engagement with the seat 40, thereby sealing off the bore 35 at the seat 40. When it is desired to vent the high pressure side of the fuel pump 11, valve member 42 is rotated relative to the body 39 using the tommy bar 44, thereby moving the valve member 42 away from the seat 40 and allowing the ball 41 to move out of engagement with the latter. This opens communication between the bore 35 and the drilling 39, thereby venting the bore 35, and hence the outlet 25, to atmosphere.

In Figure 3 there is shown a second embodiment of the connecting means. This embodiment is generally similar to the arrangement described above in relation to Figure 2, identical parts being accorded the same reference numerals with 100 added. However, in this embodiment, the head 131 of the body 129 is of reduced axial length, and the side drillings 136 are inclined at an acute angle to the axis of the bore 135.

4n Figure 4 there is shown a third embodiment of the connecting means which is gene rally similar to that described above in relation to Figure 2, similar parts Ibeing accorded the same reference numerals with 200 added.

In this embodiment, however, the head 231 of the body 229 is of substantially reduced axial length, the bore 235 is of reduced diameter, and only two side drillings 236 are provided..

In the embodiments described above, the fuel injection pump 11 of the system is of the distributor type and only one valve 20 is provided on the high pressure side thereof.

In an alternative embodiment (not shown), pump 11 is of the in-line type and a valve 20 is provided on the high pressure side of each pumping cylinder thereof. Moreover, in some applications the feed pump 12 may be omitted from the system.

WHAT WE CLAIM IS:- 1. A fuel system for an internal combustion engine, comprising a fuel injection device, a fuel injection pump having an outlet through which fuel at high pressure is delivered to said injection device by means of a high pressure line; and means connecting the high pressure line to the fuel pump outlet, said connecting means including a body having an axial bore therein, the ibody being in screw-threaded engagement with the fuel injection pump and the bore being in communication with said outlet, a side drilling communicating with said borne through which fuel passes to the high pressure line in use, and valve means including a valve member which is manually adjustable relative to said body so as to vent said bore to atmosphere.

2. A system according to Claim 1 in which the valve means includes a seat defined by a step in the bore and a portion which co-operates with the seat, adjustment of the valve member relative to the body in use enabling said portion to move into and out of engagement with the seat.

3. A system according to Claim 2, in which said portion of he valves means comprises a ball which is accommodated between the seat and the valve member.

4. A system according to Claim 3, in which said valve member is in screwthreaded engagement with the body, the valve member being adjusted in use by rotation relative to the body..

5. A system according to Claim 1, in which the body includes a screw-threaded portion which engages the fuel pump, an abutment portion spaced from the screwthreaded portion, said side drilling being disposed between said abutment portion and screw threaded portion, and the connecting means further includes a connection member connected to the high pressure line and clamped between the fuel pump and the abutment portion of the body, said connection member having a Ibore therein which communicates with the side drilling in the body.

6. A system according to Claim 5, in which the connection member has an aperture therein through which the body passes, the bore in the connection member communicating with the aperture.

7. A system according to Claim 6, including a further side drilling in said body, the valve member controlling communication between the further side drilling and the bore.

8. A system according to Claim 7, in which the further side drilling is provided in the abutment portion of the body.

9. A fuel system for an internal combustion engine comprising the combination and arrangement of parts substantially as herein described with reference to the accompanying drawings.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (9)

**WARNING** start of CLMS field may overlap end of DESC **. rally similar to that described above in relation to Figure 2, similar parts Ibeing accorded the same reference numerals with 200 added. In this embodiment, however, the head 231 of the body 229 is of substantially reduced axial length, the bore 235 is of reduced diameter, and only two side drillings 236 are provided.. In the embodiments described above, the fuel injection pump 11 of the system is of the distributor type and only one valve 20 is provided on the high pressure side thereof. In an alternative embodiment (not shown), pump 11 is of the in-line type and a valve 20 is provided on the high pressure side of each pumping cylinder thereof. Moreover, in some applications the feed pump 12 may be omitted from the system. WHAT WE CLAIM IS:-

1. A fuel system for an internal combustion engine, comprising a fuel injection device, a fuel injection pump having an outlet through which fuel at high pressure is delivered to said injection device by means of a high pressure line; and means connecting the high pressure line to the fuel pump outlet, said connecting means including a body having an axial bore therein, the ibody being in screw-threaded engagement with the fuel injection pump and the bore being in communication with said outlet, a side drilling communicating with said borne through which fuel passes to the high pressure line in use, and valve means including a valve member which is manually adjustable relative to said body so as to vent said bore to atmosphere.

2. A system according to Claim 1 in which the valve means includes a seat defined by a step in the bore and a portion which co-operates with the seat, adjustment of the valve member relative to the body in use enabling said portion to move into and out of engagement with the seat.

3. A system according to Claim 2, in which said portion of he valves means comprises a ball which is accommodated between the seat and the valve member.

4. A system according to Claim 3, in which said valve member is in screwthreaded engagement with the body, the valve member being adjusted in use by rotation relative to the body..

5. A system according to Claim 1, in which the body includes a screw-threaded portion which engages the fuel pump, an abutment portion spaced from the screwthreaded portion, said side drilling being disposed between said abutment portion and screw threaded portion, and the connecting means further includes a connection member connected to the high pressure line and clamped between the fuel pump and the abutment portion of the body, said connection member having a Ibore therein which communicates with the side drilling in the body.

6. A system according to Claim 5, in which the connection member has an aperture therein through which the body passes, the bore in the connection member communicating with the aperture.

7. A system according to Claim 6, including a further side drilling in said body, the valve member controlling communication between the further side drilling and the bore.

8. A system according to Claim 7, in which the further side drilling is provided in the abutment portion of the body.

9. A fuel system for an internal combustion engine comprising the combination and arrangement of parts substantially as herein described with reference to the accompanying drawings.