Abstract: A pump assembly includes a pump housing provided with a bore within which a pumping plunger is reciprocal along a plunger axis; a pump chamber defined at one end of the bore within which fuel is pressurized to a relatively high level; and an inlet valve housed within the pump housing and in communication with the pump chamber to control the flow of fuel into the pump chamber. A clamp member applies a clamping load to the pump housing, 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. The clamp member may be secured to the pump housing by a securing member, which may be positioned radially outwards from the bore and extend through or below a plane through the pump chamber and perpendicular to the plunger axis through the pump chamber.

Abstract: A housing for use in high pressure fluid applications comprises a first drilling having a region of enlarged diameter bounded by an upper boundary in a first plane and a lower boundary in a second plane; and a second drilling intersecting with the first drilling via an intersection region. The intersection region includes a first substantially flat surface which defines a ceiling of the intersection region and which intersects the upper boundary of the region of enlarged diameter, and a second substantially flat surface which is opposed to the first substantially flat surface and which defines a floor of the intersection region and intersects the lower boundary of the region of enlarged diameter. As the flat surfaces are in alignment with a region of maximum hoop stress they do not act as a significant stress raiser at the intersection.

Abstract: A pump assembly includes a pump housing provided with a bore within which a pumping plunger is reciprocal along a plunger axis; a pump chamber defined at one end of the bore within which fuel is pressurised to a relatively high level; and an inlet valve housed within the pump housing and in communication with the pump chamber to control the flow of fuel into the pump chamber. A clamp member applies a clamping load to the pump housing, 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. The clamp member may be secured to the pump housing by a securing member, which may be positioned radially outwards from the bore and extend through or below a plane through the pump chamber and perpendicular to the plunger axis through the pump chamber.

Abstract: A housing for use in high pressure fluid applications comprises a first drilling having a region of enlarged diameter bounded by an upper boundary in a first plane and a lower boundary in a second plane; and a second drilling intersecting with the first drilling via an intersection region. The intersection region includes a first substantially flat surface which defines a ceiling of the intersection region and which intersects the upper boundary of the region of enlarged diameter, and a second substantially flat surface which is opposed to the first substantially flat surface and which defines a floor of the intersection region and intersects the lower boundary of the region of enlarged diameter. As the flat surfaces are in alignment with a region of maximum hoop stress they do not act as a significant stress raiser at the intersection.

Abstract: A fault detection method is provided for detecting faults in an injector arrangement. The injector arrangement includes one or more piezoelectric fuel injectors connected in an injector drive circuit, and the injector drive circuit is arranged to control operation of the one or more piezoelectric fuel injectors. The fault detection method includes determining a sample voltage at a sample point in the injector drive circuit at a first sample time. The sample voltage is the voltage on an injector or is related to the voltage on an injector. The method further includes calculating a range of predicted voltages expected at the sample point at a second sample time following the first sample time, and determining the sample voltage at the sample point at the second sample time. The presence of a fault is detected if the sample voltage determined at the sample point at the second sample time is not within the range of predicted voltages.

Abstract: A method of operating a fuel injector including a piezoelectric actuator having a stack of piezoelectric elements, and wherein in use the injector communicates with a fuel rail, the method comprises: applying a discharge current to the actuator for a discharge period so as to discharge the stack from a first differential voltage level across the stack to a second differential voltage level across the stack; maintaining the second differential voltage level for a period of time; and applying a charge current to the actuator for a charge period so as to charge the stack from the second differential voltage level to a third differential voltage level; wherein the third differential voltage level is selected in dependence on at least two engine parameters, the at least two engine parameters selected from: rail pressure; the electric pulse time; and the piezoelectric stack temperature.

Abstract: A method of identifying an individual short circuit fuel injector, within an injector bank of an engine comprising a plurality of fuel injectors. Each fuel injector has a piezoelectric actuator and an associated injector select switch forming part of an injector drive circuit. The method comprises: (i) charging all of the piezoelectric actuators of the plurality of fuel injectors within the injector bank during a charge phase; (ii) at the end of the charge phase waiting for a delay period; and (iii) subsequently closing an injector select switch of a fuel injector to select said fuel injector. The method further comprises: (iv) determining a stack voltage present on terminals of the piezoelectric actuator of the selected fuel injector and storing the stack voltage in a data store. The stack voltage is indicative of an amount of charge present on the selected injector at the end of the delay period.

Abstract: A fault detection method is provided for detecting faults in an injector arrangement. The injector arrangement comprises one or more piezoelectric fuel injectors connected in an injector drive circuit, and the injector drive circuit is arranged to control operation of the one or more piezoelectric fuel injectors. The fault detection method includes determining a sample voltage at a sample point in the injector drive circuit at a first sample time. The sample voltage is the voltage on an injector or is related to the voltage on an injector. The method further includes calculating a range of predicted voltages expected at the sample point at a second sample time following the first sample time, and determining the sample voltage at the sample point at the second sample time. The presence of a fault is detected if the sample voltage determined at the sample point at the second sample time is not within the range of predicted voltages.

Abstract: A method of operating a fuel injector including a piezoelectric actuator having a stack of piezoelectric elements, and wherein in use the injector communicates with a fuel rail, the method comprises: applying a discharge current to the actuator for a discharge period so as to discharge the stack from a first differential voltage level across the stack to a second differential voltage level across the stack; maintaining the second differential voltage level for a period of time; and applying a charge current to the actuator for a charge period so as to charge the stack from the second differential voltage level to a third differential voltage level; wherein the third differential voltage level is selected in dependence on at least two engine parameters, the at least two engine parameters selected from: rail pressure; the electric pulse time; and the piezoelectric stack temperature.

Abstract: An advance arrangement controls timing of fuel delivery by a fuel pump for use in an engine. The advance arrangement includes an advance piston, a servo piston, a light load piston, and an arrangement. The advance piston is slidable within a first bore and cooperates, in use, with a cam arrangement of a fuel pump to adjust the timing of fuel delivery by the pump. A surface associated with the advance piston is exposed to fuel pressure within a first control chamber. The servo piston is slidable within a further bore provided in the advance piston to control the pressure of fuel within the first control chamber. The servo piston is responsive to speed dependent fuel pressure variations within a servo control chamber, thereby to permit adjustment of the timing in response to engine speed. The light load piston is moveable relative to the advance piston against the action of a light load control spring in response to fuel pressure variations within a light load control chamber.

Abstract: A pressure regulator for use in regulating the outlet pressure of a pump for use in an engine comprises a piston member which is moveable with respect to an outlet opening under the influence of fluid pressure acting on the piston member to control the degree by which the outlet opening is obscured. The pressure regulator comprises a biasing arrangement for applying a biasing force to the piston member which opposes the pressure of fluid acting on the piston member. The biasing arrangement comprises a moveable abutment member which is cooperable with a stop member so as to vary the rate at which the displacement of the piston member varies with fluid pressure acting on the piston member. The stop member is pre-set in a fixed position relative to the regulator housing such that movement of the abutment member is terminated when the abutment member is urged into engagement with the stop member. The invention also relates to a transfer pump comprising a pressure regulator.

Abstract: An advance arrangement controls timing of fuel delivery by a fuel pump for use in an engine. The advance arrangement includes an advance piston, a servo piston, a light load piston, and an arrangement. The advance piston is slidable within a first bore and cooperates, in use, with a cam arrangement of a fuel pump to adjust the timing of fuel delivery by the pump. A surface associated with the advance piston is exposed to fuel pressure within a first control chamber. The servo piston is slidable within a further bore provided in the advance piston to control the pressure of fuel within the first control chamber. The servo piston is responsive to speed dependent fuel pressure variations within a servo control chamber, thereby to permit adjustment of the timing in response to engine speed. The light load piston is moveable relative to the advance piston against the action of a light load control spring in response to fuel pressure variations within a light load control chamber.

Abstract: A pressure regulator for use in regulating the outlet pressure of a pump for use in an engine comprises a piston member which is moveable with respect to an outlet opening under the influence of fluid pressure acting on the piston member to control the degree by which the outlet opening is obscured. The pressure regulator comprises a biasing arrangement for applying a biasing force to the piston member which opposes the pressure of fluid acting on the piston member. The biasing arrangement comprises a moveable abutment member which is cooperable with a stop member so as to vary the rate at which the displacement of the piston member varies with fluid pressure acting on the piston member. The stop member is pre-set in a fixed position relative to the regulator housing such that movement of the abutment member is terminated when the abutment member is urged into engagement with the stop member. The invention also relates to a transfer pump comprising a pressure regulator.

Abstract: A mechanism for advancing and retarding the injection timing of a mechanically-actuated fuel injection pump. The mechanism includes a housing having a bore slidably receivable of an advance piston which cooperates with a lever of the fuel injector timing mechanism. A light load piston also in the bore cooperates with the advance piston to permit adjustment of timing under light load conditions. A rotatable cam mechanism cooperates with a flange on the light-load piston to set the axial rest position of the light-load piston and the advance piston, and hence the datum timing of the fuel injection pump. The cam may be easily set by external adjustment.

Abstract: A pressure regulator for use in regulating the outlet pressure of a pump for use in an engine comprises a piston member which is moveable with respect to an outlet opening under the influence of fluid pressure acting on the piston member to control the degree by which the outlet opening is obscured. The pressure regulator comprises a biasing arrangement for applying a biasing force to the piston member which opposes the pressure of fluid acting on the piston member. The biasing arrangement comprises a moveable abutment member which is cooperable with a stop member so as to vary the rate at which the displacement of the piston member varies with fluid pressure acting on the piston member. The stop member is pre-set in a fixed position relative to the regulator housing such that movement of the abutment member is terminated when the abutment member is urged into engagement with the stop member. The invention also relates to a transfer pump comprising a pressure regulator.

Abstract: A mechanism for advancing and retarding the injection timing of a mechanically-actuated fuel injection pump. The mechanism includes a housing having a bore slidably receivable of an advance piston which cooperates with a lever of the fuel injector timing mechanism. A light load piston also in the bore cooperates with the advance piston to permit adjustment of timing under light load conditions. A rotatable cam mechanism cooperates with a flange on the light-load piston to set the axial rest position of the light-load piston and the advance piston, and hence the datum timing of the fuel injection pump. The cam may be easily set by external adjustment.

Abstract: An advance arrangement for a fuel injection pump, comprising a housing slidably receiving an advance piston which, in use, cooperates with the fuel injection pump to adjust the timing of fuel delivery by the pump, and, a light load piston associated with the advance piston, the housing supporting an externally accessible, adjustable abutment which cooperates with the light load piston to permit setting of a rest position of the light load piston relative to said housing and thereby to permit adjustment, from the exterior of said housing, of the datum setting from which the advance arrangement adjusts fuel injection timing.

Abstract: A pressure regulator for use in regulating the outlet pressure of a pump for use in an engine comprises a piston member which is moveable with respect to an outlet opening under the influence of fluid pressure acting on the piston member to control the degree by which the outlet opening is obscured. The pressure regulator comprises a biasing arrangement for applying a biasing force to the piston member which opposes the pressure of fluid acting on the piston member. The biasing arrangement comprises a moveable abutment member which is cooperable with a stop member so as to vary the rate at which the displacement of the piston member varies with fluid pressure acting on the piston member. The stop member is pre-set in a fixed position relative to the regulator housing such that movement of the abutment member is terminated when the abutment member is urged into engagement with the stop member. The invention also relates to a transfer pump comprising a pressure regulator.

Abstract: An electrically operated trigger valve for a fuel injection pump includes a valve member secured to an armature to form an armature and valve member assembly. The valve member is slidably mounted in a bore and controls communication between the fuel inlet and a fuel outlet. In use, the valve is maintained in its closed position by energizing a stator coil to attract the armature. When the stator is de-energized the armature and valve member assemblies moved in the valve opening direction by a valve opening spring. The length of the valve opening spring is such that when the valve is in the fully open position a gap exists between one end of the opening spring and its adjacent seat. Accordingly, initial movement of the armature and valve member assembly in the closing position, upon subsequent energization of the state of coil, is not opposed by the spring until the gap has been eliminated by initial movement of the armature.

Abstract: A governor arrangement for an internal combustion engine is disclosed which comprises a plurality of weights rotatable with a rotatable drive shaft and pivotable with respect to the shaft. The weights are engageable with a washer which, in turn, engages a sleeve. The sleeve engages a lever the position of which is used to control the setting of a metering valve. A hydrodynamic bearing arrangement is provided between the sleeve and washer. A drive arrangement may be provided to drive the washer when the rotational speed of the shaft is insufficient to cause the weights to move the sleeve.