Abstract:
An electro-valve for discharging a common rail while maintaining a minimum pressure, comprising an electro-magnetic coil inside which is arranged a movable plunger, controlling the displacements of a movable axis engaging a ball valve, said movable plunger being urged in the closing position of the ball valve by a spring housed inside a bearing cap, wherein a bottom wall of the bearing cap surrounds an external surface of the movable plunger, wherein a clearance between the external surface of the plunger and an internal wall of the bearing cap is filled with a film of fuel, the opening movement of the plunger causing the fuel to flow from a room situated on top of the plunger to a bore in which the axis is arranged, wherein a sleeve of a controlled thickness is arranged around the plunger within the clearance to set the thickness of said film of fuel.
Abstract:
A pumping assembly having a high-pressure pumping stage and an integrated transfer pumping stage. The pumping assembly comprises a cam (104;204) arranged for eccentric rotation about a drive shaft axis (A), a cam rider (106;206), a cam follower (112;212), the cam follower (112;212) having reciprocal movement parallel to a cam follower axis (Q) that is perpendicular to the drive shaft axis (A), a high-pressure pumping head having a high-pressure pumping chamber, and a pumping element driven by the cam follower (112;212). The pumping assembly further comprises a first chamber (150a;250a), inlet means (174;274) for allowing fluid flow into the first chamber (150a;250a), and outlet means (150b,163,166,166a;250b,263,266,266a) for receiving fluid from the first chamber (150a;250a) and for delivering fluid to the high-pressure pumping head. Rotation of the cam (104;204) about the driveshaft axis (A) causes an increase in volume of the first chamber (150a;250a) during a first part of the pumping cycle and a decrease in volume of the first chamber (150a;250a) during a second part of the pumping cycle, so as to effect a transfer pumping of fluid from the inlet means (174;274) to the outlet means (150b,163,166,166a;250b,263,266,266a) for delivery to the high-pressure pumping head.
Abstract:
A pumping assembly (100) suitable for use as high-pressure fuel pump in a fuel injection system is disclosed. The pumping assembly comprises drive means comprising a drive plate (114) rotatable about a drive axis (A) and including a recess (120) arranged eccentrically with respect to the drive axis (A); a guide arrangement (122, 122a) received, at least in part, in the recess (120) of the drive plate (114) so that rotary movement of the drive plate (114) gives rise to translatory movement of the guide arrangement (122, 122a); a pumping element (108); and a slide member (112) associated with the pumping element (108). The slide member (112) is in sliding engagement with the guide arrangement (122, 122a) to define at least one sliding interface (196, 198) between the guide arrangement (122, 122a) and the slide member (112), such that rotary movement of the drive plate (114) causes reciprocal linear movement of the pumping element (108) along a pumping axis (Q).
Abstract:
A bearing assembly (10; 100) suitable for use as a journal bearing for a high-pressure fuel pump is disclosed. The bearing assembly comprises a generally tubular bearing bush (20; 200) made entirely from a PEEK-based material, and defining an inner bearing surface (22; 222), and a housing (40; 400) comprising a generally cylindrical bore (42; 442) for receiving the bush (20; 200). The bush (20; 200) and the housing (40; 400) are arranged concentrically around a bearing axis (A). The housing (40; 400) includes cooling means (54, 56, 58; 454) for cooling the bearing assembly (10; 100), in use.
Abstract:
The present application relates to a pump unit (101; 201; 201') for a fuel injection system. The pump unit (101; 201; 201') has an inlet valve (107; 207), an outlet valve (109; 209), a supply line (111; 211) for supplying fuel, a pumping chamber (105; 205; 205'), and a plunger (119; 217; 217') for pressurising fuel in the pumping chamber (105; 205; 205'). The inlet valve (107; 207) comprising an inlet valve member (113; 221; 221') movable between a first position and a second position. The inlet valve member (113; 221; 221') has an aperture (117; 229) formed therein. The aperture (117; 229) provides a first fluid pathway between the pumping chamber (105; 205; 205') and the supply line (111; 211) when the inlet valve member (113; 221; 221') is in its first position, and the aperture (117; 229) provides a second fluid pathway between the pumping chamber (105; 205; 205') and the outlet valve when the inlet valve member is in its second position.
Abstract:
A method of fuel injection, comprising constructing an hydraulic behaviour profile by fuel pressure measurement, using the hydraulic behaviour profile to predict fuel pressure that will prevail in a fuel injector during an injection event, and supplying a control signal to the fuel injector to control the amount of fuel injected during the injection event in accordance with the predicted fuel pressure. By predicting the fuel pressure that will prevail during an injection event, the fuel delivered during the injection event can be accurately controlled.
Abstract:
A driveshaft (401) for driving a rotor of a positive displacement pump has an axis of rotation (410) and a plurality of flat surfaces (412) arranged symmetrically around and substantially parallel to it. There are also a plurality of cylindrical surfaces (414) arranged around the axis of rotation and extending between adjacent flat surfaces (412). A length of the flat surfaces (412) in a direction parallel to the axis of rotation (410) is greater than a length of the cylindrical surfaces (414) in a direction parallel to the axis of rotation.