Abstract:
A fuel pump arrangement for a fuel injection system is described. The fuel pump arrangement comprises one or more cam-driven pump units (110a, 110b), and the or each pump unit (110a, 110b) comprises a pumping chamber (112a, 112b) and a pumping element (114a, 114b) for pressurising fuel in the pumping chamber (112a, 112b). The or each pumping element (114a, 114b) is driven by a respective cam (116a, 116b) of the fuel pump arrangement to undergo at least one pumping stroke per revolution of the cam (116a, 116b). The fuel pump arrangement is configured such that the fuel volume displaced in a first pumping stroke is greater than the fuel volume displaced in a second pumping stroke. In this way, the efficiency of operation of the fuel pump arrangement can be improved.
Abstract:
The present invention relates to a rotary fuel pump (101). The pump (101) has a rotor (107) and at least one pumping element (115) for supplying high pressure fuel. A cam box (123) containing a cam arrangement (103) is provided for actuating the at least one pumping element (115). A speed dependent fuel pressure line (129) is provided for supplying speed dependent fuel pressure to an advance arrangement (125) for adjusting the timing of fuel delivery by the pump (101). A first vent line (131) is provided for venting air from the speed dependent fuel pressure line (129). The first vent line (131) is in fluid communication with a collection chamber (137) for collecting air vented from the speed dependent fuel pressure line (129). A second vent line (141) is provided for venting air from the collection chamber (137). The second vent line (141) is a helical groove (141) formed in the rotor (107) or a pump housing (105). The present invention also relates to a rotor (107) for a fuel pump (101).
Abstract:
There is provided a fuel pump assembly for use in an internal combustion engine. The fuel pump assembly comprises a pumping plunger (16) for pressurising fuel within a pumping chamber (32) during a plunger pumping stroke; and a cam follower arrangement (18, 20) for imparting drive to the pumping plunger (16) including a cam follower member (18) which cooperates with the pumping plunger (16). The cam follower arrangement (18, 20) is biased into engagement with a cam drive (22, 26) whilst a degree of relative movement along the plunger axis is permitted between the cam follower member (18) and the pumping plunger (16). At least one of the pumping plunger (16) and the cam follower member (18) includes a surface provided with a feature which defines together with a facing surface of the other of the pumping plunger (16) and the cam follower member (18), a cushioning volume (44) there between for receiving fluid to provide a cushioning effect as the pumping plunger (16) and the cam follower member (18) move into contact with one another, in use. The feature includes a flat central portion (40) and an annular region (42) which is conical in form and which is angled relative to the facing surface.
Abstract:
A serviceable filtration arrangement for use in an internal combustion engine of a vehicle to remove contaminants from a liquid to be filtered. The filtration arrangement (1, 101) comprises an upstream filtration element (7, 107) and a downstream filtration element (5, 105). Upon servicing of the vehicle the upstream filtration element (7, 107) can be replaced independently of the downstream filtration element (5, 105). The upstream filtration element (7, 107) has a filtration media (61 ) which has characteristics that have been selected such that the upstream filtration element (7, 107) becomes clogged before a filtration media (51) of the downstream filtration element (5, 105) becomes clogged.
Abstract:
A pump head (14) for a high-pressure fuel pump is disclosed. The pump head comprises a head housing including a body portion (24), and a turret portion (30) extending from the body portion (24), a pumping chamber (36) defined within the body portion (24), a pumping element bore (34) for receiving a pumping element (32) in use, the pumping element bore (34) extending from the pumping chamber (36) and through the turret portion (30), and a leakage return passage (74). The pump head (14) further comprises a sleeve (70) arranged around the turret portion (70) to define a leakage flow path (72) to allow fuel flow from the pumping element bore (34) to the leakage return passage (74). The pump head is suitable for use in a fuel pump of the type in which a cam drive arrangement of the pump is lubricated by engine oil, since contamination of the engine oil with fuel can be minimised.
Abstract:
An injection device for administering a reagent into an exhaust passage of an internal combustion engine, the injection device having an axis (A) along its length and comprising an outwardly opening valve member (14) having a seating surface which is engageable with a valve seating region (30). A seating member provided with an internal bore (12) which defines the valve seating region (30), wherein the internal bore (12) further defines a flow re-directing region (32) downstream of the valve seating region (30). The seating member (10) has an end face (36; 136) provided with a feature (38; 138; 238; 338; 438; 538) which intersects with at least a portion of the flow re-directing region (32) to define, together with the flow re-directing region (32), a spray path for reagent exiting the injection device when the valve member (10) is moved outwardly from the bore (12) away from the valve seating region (30). The spray path has a variable spray angle, relative to the axis A, around the circumference of the valve seating region (30).
Abstract:
A needle for use in a needle valve, such as the needle valve of a fuel injector, comprises a tip section (2), a first guide section (1a) and a second guide section (3). The tip section (2a) has a needle tip. The first guide section (1a) is remote from the needle tip. The second guide section comprises a tube, wherein the first guide section (1a) and the tip section (2a) are comprised in an integrated inner needle component (7) extending through the tube (3). A method of manufacturing such a needle is also described.
Abstract:
A housing (30) for use in high pressure fluid applications comprising a first drilling (32a, 32b), defining a first axis, and having a region of enlarged diameter (32b) bounded by an upper boundary (36) in a first plane and a lower boundary (38) in a second plane; and a second drilling (42), defining a second axis, and intersecting with the first drilling (32a, 32b) via an intersection region (44). The intersection region (44) includes a first substantially flat surface (54) which defines a ceiling of the intersection region (44) and which intersects the upper boundary (36) of the region of enlarged diameter (32b), and a second substantially flat surface (56) which is opposed to the first substantially flat surface (56) and which defines a floor of the intersection region (44) and intersects the lower boundary (38) of the region of enlarged diameter (32b). As the flat surfaces are in alignment with a region of maximum hoop stress (i.e. at the upper and lower boundaries of the enlarged diameter region of the first drilling) they do not act as a significant stress raiser at the intersection (44). In another aspect of the invention the first drilling need not have a region of enlarged diameter, with the intersection region having tangential surfaces to the circumference of the first drilling so that the intersection region does not intersect with a region of hoop stress.
Abstract:
A fuel injector (300) comprising a solenoid actuator (200) and a housing is disclosed. The housing comprises a first housing body (302) having a recess (308) for receiving the actuator (200) and an end face (303), and a second housing body (304) for receiving the valve member (232) and having a sealing face (305) sealable against the end face (303) of the first housing body (302). The actuator comprises a generally cylindrical core member (202) having a longitudinal axis (A) and defining, at an end thereof, an inner pole face (210) of the actuator, a wire coil (212) disposed around the core member (202) and arranged to be connected to a power source in use so as to generate a magnetic field around the coil, an outer ring (218) arranged concentrically around the end of the core member (202) and defining an outer pole face (220) of the actuator, and a support ring (216) of non-magnetic material having a relatively low magnetic permeability, the support ring (216) being disposed between the end of the core member (202) and the outer ring (218). In one embodiment, the actuator (200) is receivable in a recess (308) in a housing (302), and is arranged such that substantially all of the flux in a part of a magnetic circuit defined by the magnetic field is guided to pass between the outer ring (218) and the housing (302) in use of the actuator. At least the outer pole face (220) is coplanar with the end face (303) of the first housing body (302).
Abstract:
A pump assembly (30) for use in an internal combustion engine comprises a pump housing (32a, 32b) provided with a bore (34) within which a pumping plunger (36) is reciprocal along a plunger axis; a pump chamber (38) defined at one end of the bore (34) within which fuel is pressurised to a relatively high level as the pumping plunger (36) reciprocates within the bore (34), in use; and an inlet valve (40, 40a, 40b) housed within the pump housing (32a, 32b) and in communication with the pump chamber (38) to control the flow of fuel into the pump chamber (38). A clamp member (46) applies a clamping load to the pump housing (32a, 32b), which has at least a component that is aligned with the plunger axis, through a surface of the pump housing located approximately axially above the bore (34). This has the effect of generating a compressive stress in the pump housing in close proximity to the plunger bore (34) to counter tensile stress within the pump housing due to pressurised fuel within the pump chamber (38). The clamp member (46) may be secured to the pump housing (32a, 32b) by at least one securing member (48), which may be positioned radially outwards from the bore (34) and extend through or below a plane through the pump chamber (38) and perpendicular to the plunger axis through the pump chamber (38).