Abstract:
An armature (132; 232; 332) for a solenoid actuator is disclosed. The armature comprises a first face (170; 270; 370) comprising a recess (174; 274; 374) suitable for receiving a biasing spring in use of the armature; a second face (172; 272; 372) opposite the first face (170; 270; 370); and fluid communication means (178; 210; 310) for providing a fluid flow path through the armature between the recess (174; 274; 374) and the second face (172; 272; 372) in use of the armature. The first face (170; 270; 370) is uninterrupted by the fluid communication means (178; 210; 310). The invention reduces the risk of cavitation damage during operation of the actuator. In one application, the actuator is used in a fluid pump (100; 200) for a selective catalytic reduction system.
Abstract:
A pump assembly for an internal combustion engine comprising a pump housing (40), at least one pumping arrangement having a pumping plunger (56, 58) for pressurising fluid within a pump chamber; a drive shaft (46) carrying a cam (48) and a cam rider (50) which cooperates with the pumping arrangement to drive plunger movement along a plunger axis; and a plate (74; 174; 274; 374) coupled, on one side (74b), to the cam rider (50) and, on its other side (74a), to the housing (40) by coupling means (84, 86, 80, 82; 84, 180; 280, 286; 380, 480).The coupling means is arranged to constrain movement of the plate (74; 174; 274; 374) relative to the housing (40) in a first linear direction and to constrain movement of the cam rider (50) relative to the plate in a second linear direction, and to prevent angular movement of the cam rider (50) about its axis. Wear of the plunger, or of any intermediate component between the cam rider and the plunger, can be reduced as the cam rider is unable to tilt about its axis.
Abstract:
A method of dosing a reagent into an exhaust gas stream of an internal combustion engine (3) having an SCR catalyst, the method comprising injecting reagent from a reagent tank (20) into the exhaust gas stream at a position upstream of the SCR catalyst using a reagent injector (40) in accordance with a first dosing schedule in order to remediate a predetermined proportion of NOx in the exhaust gas stream, the first dosing schedule being associated with a first range of engine operating conditions; and injecting reagent from the reagent tank (20) into the exhaust gas stream at a position upstream of the SCR catalyst using a reagent injector (40) in accordance with a second dosing schedule in order to enable heat transfer between the reagent injector (40) and said injected reagent, the second dosing schedule being associated with a second range of engine operating conditions. Dosing in accordance with said first or said second dosing schedule is carried out in dependence on whether engine operating conditions lie within said first or said second range of engine operating conditions, and the proportion of NOx in the exhaust gas stream which is remediated by dosing using said second dosing schedule is less than said predetermined portion. The method further comprises sensing the level of reagent in the reagent tank (20); and halting the first dosing schedule when the sensed level of reagent drops below a predetermined level.
Abstract:
A three-way control valve for controlling communication between (a) a first passage (38) and a second passage (36) and (b) a third passage (30) and the second passage (36), comprises a first housing (14) provided with a guide bore (34) for a control valve member (32a, 32b), whereby movement of the control valve member (32a, 32b) is guided within the guide bore (34). The valve includes a first valve seat (48), defined by a second housing (12), with which the control valve member is engageable to control communication between the first and second passages (38, 36), and a second valve seat (50) defined by the first housing (14) with which the control valve member is engageable to control communication between the second and third passages (36, 30). An intermediate housing (16) is located between the first and second housings (14, 12), the second passage (36) being defined within the intermediate housing (16). The invention also extends to a fuel injector for a high pressure fuel injection system comprising such a three-way control valve.
Abstract:
A fuel injector mountable with respect to a combustion chamber for delivering fuel thereto, the combustion chamber comprising a chamber ceiling (30) and a chamber wall, the fuel injector comprising a nozzle body (21) having a primary nozzle axis (A- A); a first outlet opening (23; 33) having a first axis (27; 37); a second outlet opening (24; 34) having a second axis (28; 38); and means for controlling fuel delivery through the first and second outlet openings (23, 24; 33, 34). The means for controlling fuel delivery comprises an inner valve needle and an outer valve needle, and is arranged to permit fuel delivery from only the first outlet opening (23, 33), or through both the first and second outlet openings (23, 24; 33, 34) together. The first and second outlet openings (23, 24; 33, 34) are oriented such that, in use, when fuel delivery is permitted through only said first outlet opening (23; 33), a first spray formation is injected along the first axis (27; 37), the first spray formation reaching a first target distance below said chamber ceiling (30) at a radial distance from the primary nozzle axis (A-A). When fuel delivery is permitted through both openings (23, 24; 33, 34) together, respective first and second spray formations are injected along the respective first and second axes (27, 28; 37, 38) to merge externally of the injector so as to give rise to a combined spray formation having a third axis (29; 39). The combined spray formation reaches a second targetdistance below said chamber ceiling (30) at said radial distance from the primary nozzle axis (A-A), and is substantially equivalent to a spray formation delivered as if from a single outlet opening having a diameter greater than that of the first outlet opening (23; 33). The first target distance is less than the second target distance.
Abstract:
A dosing device (1) for administering a reducing agent (2) into an exhaust chamber (4) of an internal combustion engine, and being adapted for mounting within a port (10) of said exhaust chamber (4), the device comprising: a nozzle body (6) having a first end (27) from which reducing agent is sprayed and a second end (28), the first end (27) comprising a first mounting point (8) and the second end (28) comprising a second mounting point (9); an insulating jacket (5) at least partially surrounding the nozzle body (6) and being mounted to the nozzle body (6) at the first and second mounting points (8, 9) so as to define a compartment (11) between the insulating jacket (5) and the nozzle body (6). The compartment (11) is substantially evacuated and the dosing device (1) is configured such that, when the dosing device (1) is mounted within the port (10) of the exhaust chamber (4), the nozzle body (6) is separated from the port (10) by the substantially evacuated compartment (11), the insulating jacket (5) thereby serving to insulate the nozzle body (5) from the port (10). The dosing device of the invention is advantageously insulated from the elevated temperatures in the surrounding environment, thereby allowing for the reagent to be maintained at an optimal working temperature range.