GB2114237A

GB2114237A - Fuel treatment device

Info

Publication number: GB2114237A
Application number: GB08300917A
Authority: GB
Inventors: Stephen Edwards
Original assignee: Lucas Industries Ltd
Current assignee: ZF International UK Ltd
Priority date: 1982-01-23
Filing date: 1983-01-13
Publication date: 1983-08-17
Also published as: GB2114237B; GB8300917D0

Abstract

A fuel treatment device for incorporation into a fuel system of an internal combustion engine comprises a mounting 14 carrying a can 16 which accommodates a fuel filter element 17. The mounting defines fuel inlet and outlet ports 27, 24 for connection into the fuel system. The mounting also carries a piston assembly 28 located within a chamber 26 in the mounting, the piston assembly being movable from the exterior of the device. One of the ports (port 27) communicates with the chamber on one side of the piston and the chamber on the other side of piston assembly communicates with the other port (port 24) by way of a non-return valve. The piston assembly also carries a valve 35, 36 whereby when the piston assembly is actuated a flow of fuel and/or air takes place between the ports. <IMAGE>

Description

SPECIFICATION Fuel treatment device This invention relates to a fuel treatment device for incorporation into the fuel system of an internal combustion engine.

The fuel treatment device may for example include a fuel filter element th rough which fuel is drawn to remove solid contaminentfrom the fuel or it may include a fuel heater located within a chamber forming part of the device. In each case the device will include an inlet port and an outlet portforconnection into the fuel system, the inlet and outlet ports conveniently being located within a mounting of the device. It is well known thatwhen the fuel tankassociatedwith the system is drained by operation of the associated engine, air is drawn into the system and that the air in the system must be purged before a satisfactory fuel flow can be obtained.It is known to provide a hand operable priming pump for this purpose however, the provision of this pump as a separate item adds considerablytothecostofthefuel system.

It is an object of the invention to provide a fuel treatment device in a form including a priming pump.

According to the invention a fuel treatment device for incorporation into the fuel system of an internal combustion engine comprises a mounting whereby the device can be mounted on a support in use, a fuel treatment chamber defined in a part adapted to be secured to the mounting, inlet and outlet ports defined by the mounting whereby the device can be connected into an engine fuel system, a pump chamber defined in said mounting, a piston assembly mounted in said pump chamber and operable from exterior of the device, one of said ports communicating with said chamber on one side of said piston assembly, a non-return valve through which the pump chamber on the other side ofthe piston assembly is in communication with said fuel treatment chamber, and further valve means carried by said piston assembly and operable to allow fuel flow from one side ofthe piston assemblyto the other side thereof.

Examples of fuel treatment device in accordance with the invention will now be described with reference to the accompanying drawings in which:- Figure 1 is a sectional side elevation of a fuel treatment device which incorporates a fuel filter element and a sedimentation chamber.

Figure 2 is a sectional side elevation showing an alternativearrangementofthe mounting and in particular the pump assembly, Figure 3 shows a sectional side elevation of a further form of pump assembly, and Figure 4 shows a sectional side elevation of another form of the device.

Referring to Figure 1 of the drawings the fuel treatment device is shown generally at 10 with a fuel supply tank indicated at 11 and low pressure and high pressure fuel pumps at 12 and 13 respectively, these components forming a fuel system for a compression ignition engine.

The device includes a mounting 14which is provided with lugs not shown whereby it can be secured to any convenient support. The mounting defines an annular rim 15 which carries a seal whereby sealing engagement can be established with the rim of a can 15 defining a fuel treatment chamber. Mounted within the can is a fuel filter element 17 which is positioned between the wall of the can and a central tubular member 18, the element being formed from paper or other suitable material. The filter element is supported on a apertured plate 18which is located against a step defined in the can and integrallyformed with the apertured plate is a hollow truncated member 20 which defines a central aperture 21 communicating with the flow passage defined by the member 18.The mounting 14 carries a spigot portion 22 which carries a circumferential seal for engagement with the inner surface ofthe tubular member 18 in orderto define a fuel tight fit. Moreover, the mounting defines an annular recess 23 which communicates with an outlet port 24 formed in the mounting.

The spigot 22 defines a through passage 25 which communicateswithoneendofa pumpchamber26 which is formed within the mounting. The other end of the chamber communicates with a fuel inlet 27 which is connected to the fuel tank 11.

Mountedwithin the pump chamber26 is a piston assembly generally indicated at 28 and which includes a piston 29 having an integral actuating rod 30 which extends through a suitable apertureformed in the mounting, to the exterior ofthe device. The aperture in the mounting is closed bya gland nut31 and an "0" ring seal 32 is urged bythe gland nut31 into sealing engagement with the rod 30. Exterior of the mounting the rod carries an actuating knob 33 which is shaped on its undersideto provide locationfora coiled compression spring 34 interposed between the knob and the mounting.

In the peripheral surface of the piston there is formed a circumferential groove 35 having substantial width and located within the groove is an "0" ring 36 formed from suitable fuel resistant material. The ring 36 can move axiallywithin the groove 35 aswill be described and the end portion ofthe groove 35 which is closerto the rod 30 defines ports 37 which communicatewith the pump chamber 26 on the side of the piston assembly remote from the rod 30. The piston 29 has a substantial clearance with the wall of the pump chamber 26 buttheclearance is not sufficient to allow passage of the ring 36 between the wall of the chamber and the piston.

The passage 25 defined in the spigot 22 incorporates a non-return valve which is arranged such that fuel can flow from the chamber 26 into the interior of the tubular member 18 but not in the reverse direction.

In operation, assuming that the fuel system is completelyfull offuel,the pump l2will drawfuel from the outlet 24, the fuel flowing to the outlet by way of the filter element 17 from the lower portion ofthe can.

The fuel flowing into the lower portion of the can flows through the inlet 27 and through the passages 37 the ring 36 in this situation being disposed below the level ofthe ports 37. From the ports 37 the fuel flows into the lower portion of the pumping chamber 26 and through the passage 25 past the non-return valve therein, into the interior of the tubular member 18 and through the aperture 21. Droplets of water in the fuel and any heavy solid contaminent in the fuel will accumulate at the bottom ofthe can and the fuel flow into the element will be around the periphery ofthe truncated member 20.

If the fuel tank is allowed to run dry then air will enter the fuel system and normal flow offuel from the outlet 24 will occur until the level offuel drops belowthe lower rim ofthe member 20. When this occurs airwill be drawn into the filter element and will pass to the outlet 24. When the fuel tank is replenished a considerable volume ofairwill remain in the system and in order to purge the air, the knob 33 is depressed against the action ofthe spring 34. The action of depressing the knob moves the piston 29 downwardly and the ring 36 moves to the position in which it is shown. Air is forced from the pumping chamber by way ofthe valve and during this time fuel is drawn towards and possibly into the inlet 27 from the tank.

When the knob is released, the piston returns under the action of the spring 34 and during the return motion the ring 36 moves within the groove 35 to permit passage of air and possibly also fuel, through the passages 37 into the lower portion of the pump chamber 26. This process is repeated until the fuel system has been purged of air. It will be understood thatthe pumps 12 and 13 include some provision for venting the airwhich is forced through the outlet 24 and normallythiswill include a return pipe to the fuel tank.

As shown in Figure 1 the lower portion of the can mounts a sensing device 38 which may be utilized to provide a signal to the operator ofthe associated enginethatthe level of water and contaminent contained in the lower portion of the cam has risen to a dangerous value.

The mounting 14 of the device shown in Figure 2 is substantially the same as the mounting which is shown in Figure 1. There is a difference however in the construction of the piston assembly 28 and it will be seen thatthe ports 37 are omitted. In order to permit fuel flow between the opposite sides ofthe piston assembly the portion ofthe piston which defines the lowerwall ofthe groove is provided with slots as indicated at 39. In operation, the fuel which passes between the opposite sides of the piston either due to the action ofthe pump 12 or due to movement of the piston, flows between the ring 36 and the walls ofthe groove 35.In the device shown in Figure 2, the filter element has been omitted and the spigot 22 as such is replaced by a valve housing 40 which is carried by a truncated conical member 41 which serves a similar purpose to the member 20 shown in Figure 1. The can 16 has also been replaced by a more substantial container42which mounts a sensing device 38.

Turning now to Figure 3, a further modified form of piston assembly 43 is illustrated, The piston assembly 43 includes a piston 44which is provided with a conventional form of lip seal 45forengagementwith the internal surface ofthe pumping chamber 26. The piston assembly also mounts a one-way valve generally indicated at47 and a furthervalve (not shown) similarto thatwhich is shown in Figure 1, is mounted at the lower end of the chamber 26. The valve 47 controls the flow of fuel through passages 48 defined in the piston.

In operation, the two valves are opened by flow of fuel underthe action ofthe pump 12 but operate as inlet and outlet checkvalves when the piston assem bly is moved to effect purging orofairfrom the fuel system.

In the arrangement described the pump is disposed between thefllterelementand the inletto the device.

Asaresultwhentheactuating knob is depressedfuel and/orair inthe pump chamber isforced through the filter elementto the outlet. The pump can be disposed between the outlet and the filter element and in this case it is necessary to reverse the action of the valves.

Moreover, with this arrangement the pumping of the fuel and/or airthrough the outlet is achieved bythe action of the spring which biasesthe piston.

An example of a device in which the pump is positioned between the filter element and the outlet is seen in Figure 4 and with reference to this drawing the inlet 27 communicates directly with thefilter element 17 by way of a passage 43. The tube 18 in this example forms the outlet from the element and engaged within the tube is a spigot44which forms partofa pump assembly which locates in a tapered recess 45 formed in the mounting 46.

The pump assembly comprises a housing 47 defining a bore 48, the housing having a reduced hollowexterior49 extending from one end. The open end ofthe housing is closed bya plate 50 which defines the spigot and the plate and body are held in assempled relationship and in the recess 45 by deforming the material at the open end of the recess 45.

The spigot 44 is provided with a through passage in which is located a spring loaded plate valve 51 arranged to allowfuelflowfromthe interior of the tube 18 into the pump chamber. Slidable within the extension 49 is a rod 52 upon which is mounted a head 53 which constitutes the piston ofthe pump. The rod carries a knob 54 and is biased by a coiled compression spring 55. The cylindrical surface ofthe head 53 defines a clearance with the bore 48 and formed in the surface is a groove 56 in which is located an "0" ring 57. The ring 57 does notfill the groove but its natural resilience and its size is such that it is held in engagement with the surface ofthe bore 48.The rod is provided with a groove in which is located a seal ring and a further seal ring 58 is located aboutthe extension to form a second seal between the rod and the extension when the spring is in its fully extended position.

The junction wall between the housing 47 and the extension is provided with a plurality of apertures 59 which lead into a space communicating with an outlet 60. Moreover, a ball valve 61 is provided which controls flow of fuel through an opening 62 extending into a recess and apertures 63 in the head 53 leading from the recess. In use, when the knob is depressed fuel and/or airflows pastthe ball valve and is transferred between the portions ofthe bore on the opposite sides ofthe piston.Thevalve 51 remains closed during this movement. When the knob is released the valve 51 opens to allow flow of fuel and/or air into the bore 48 from the filter element and the fuel and/or air in the upper portion of the bore flows to the outlet 60 by way ofthe openings 59. The normal flow offuel through the device lifts the ball valve 61 from its seating and also opens the valve 51.

The aforesaid pump assembly may be formed from plastics.

By the arrangements described the mounting ofthe fuel treatment device is arranged to constitute the housing of a pump which can be utilized when it is required to purge the fuel system of air.

Claims

1. Afuel treatment device for incorporation into the fuel system of an internal combustion engine comprising a mounting whereby the device can be mounted on a support in use, a fuel treatment chamber defined in a part adapted to be secured to the mounting, inlet and outlet ports defined by the mounting whereby the device can be connected into an engine fuel system, a pump chamber defined in said mounting, a piston assembly mounted in said pump chamber and operable from exterior ofthe device, one of said ports communicating with said chamber on one side of said piston assembly, a non-return valvethrough which the pump chamberon the other side of the piston assembly is in communication with said fuel treatment chamber, and further valve means carried by said piston assembly and operable to allow fuel flowfrom one side of the piston assemblytothe other side thereof.

2. A device according to Claim 1 in which said furthervalve means comprises an annular sealing ring which is axially movable within a circumferential groove formed in the exteriorwall of a piston forming partofthe piston assembly, said sealing ring in one extreme position acting to prevent passage offuel between the opposite sides of the piston assembly.

3. A device according to Claim 2 in which said circumferential groove has a depth greaterthan the width of said sealing ring, said sealing ring being located against one side wall of the groove in said one extreme position.

4. A device according to Claim 3 including ports or grooves formed in the piston and through which fuel canflowwhen said sealing ring is away from said one extreme position.

5. A device according to Claim 4 in which said ports are formed in the base wall of said groove and external to the hollow interior of the piston said hollow interior being open to said other side of the piston assembly.

6. A device according to Claim 4 in which said grooves are formed in the other side wall of the groove.

7. Afuel treatment device for incorporation into a fuel system of an internal combustion engine comprising the combination and arrangement of parts substantially as hereinbefore described with referenceto Figure 1 ofthe accompanying drawings.

8. Afuel treatment device for incorporation into a fuel system of an internal combustion enginecomprising the combination and arrangement of parts substantially as hereinbefore described with reference to Figure 2 of the accompanying drawings.

9. Afuel treatment device for incorporation into a fuel system of an internal combustion engine comprising the combination and arrangement of parts substantially as hereinbefore described with reference to Figure 3 of the accompanying drawings.

10. Afuel treatment device for incorporation into a fuel system of an internal combustion engine comprising the combination and arrangement of parts substantially as hereinbefore described with reference to Figure 4 ofthe accompanying drawings.