Abstract: A fuel system for supplying gaseous fuel to an onboard power plant of a vehicle, the fuel system comprising at least a first tank configured to receive pressurised gaseous fuel for supply to the power plant, in use; a source of auxiliary control fluid for supply to the first tank; and a valve arrangement which is operable to control the supply of auxiliary control fluid to the first tank so as to control the discharge of the gaseous fuel from the first tank; wherein the first tank includes a movable separation element for separating the auxiliary control fluid from the gaseous fuel within the first tank.

Abstract: A gas supply system comprises a first valve arrangement permitting gas to be supplied from a gas tank to first and second storage chambers configured to accommodate gas and compression fluid, and permit gas to be delivered from the storage chambers. A second valve arrangement permits compression fluid to flow to/from the storage chambers. Compression fluid is delivered to the first and second storage chambers via the second valve arrangement by a hydraulic pump having a primary and secondary drive inputs. Compression fluid is evacuated from the first and second storage chambers via a hydraulic motor having a drive output. The drive output of the hydraulic motor is coupled to the secondary drive input of the hydraulic pump, such that when compression fluid is evacuated from the first or second storage tank through the hydraulic motor, energy is recovered from the compression fluid to drive the hydraulic pump.

Abstract: A gas supply system comprises a first valve arrangement permitting gas to be supplied from a gas tank to first and second storage chambers configured to accommodate gas and compression fluid, and permit gas to be delivered from the storage chambers. A second valve arrangement permits compression fluid to flow to/from the storage chambers. Compression fluid is delivered to the first and second storage chambers via the second valve arrangement by a hydraulic pump having a primary and secondary drive inputs. Compression fluid is evacuated from the first and second storage chambers via a hydraulic motor having a drive output. The drive output of the hydraulic motor is coupled to the secondary drive input of the hydraulic pump, such that when compression fluid is evacuated from the first or second storage tank through the hydraulic motor, energy is recovered from the compression fluid to drive the hydraulic pump.

Abstract: A fuel system for supplying gaseous fuel to a power plant comprises a tank array comprising at least a first tank and a second tank configured to receive pressurised gaseous fuel for supply to the power plant, in use, from a filling station; a source of auxiliary control fluid for supplying auxiliary control fluid to the tank array when the fuel system is disconnected from the filling station; and a pump for pressurising auxiliary control fluid to be supplied to the tank array when control fluid flows through the pump in a forward direction. The fuel system also includes an energy store and a valve arrangement which is operable to control the supply of auxiliary control fluid to the tank array so as to control the discharge of the gaseous fuel from the tank array.

Abstract: A fuel system for supplying gaseous fuel to an onboard power plant of a vehicle, the fuel system comprising at least a first tank configured to receive pressurised gaseous fuel for supply to the power plant, in use; a source of auxiliary control fluid for supply to the first tank; and a valve arrangement which is operable to control the supply of auxiliary control fluid to the first tank so as to control the discharge of the gaseous fuel from the first tank; wherein the first tank includes a movable separation element for separating the auxiliary control fluid from the gaseous fuel within the first tank.

Abstract: A fuel system for supplying gaseous fuel to a power plant comprises a tank array comprising at least first and second tanks, each tank being configured to receive pressurised gaseous fuel for supply to the power plant; and an auxiliary control fluid delivery system. The auxiliary control fluid delivery system comprises a reservoir of auxiliary control fluid; an auxiliary control fluid pipeline, configured to enable supply of the auxiliary control fluid to the tank array so as to cause discharge of the gaseous fuel held in the tank array and to enable return of the auxiliary control fluid from the tank array; and a valve arrangement which is operable to control the supply and return of auxiliary control fluid to and from the tank array, respectively, so as to control the discharge of the gaseous fuel.

Abstract: A roller tappet assembly for a reciprocating pump comprises: a tappet body; a pin element comprising: first and second opposing end portions that engage respective formations in the tappet body to retain the pin element, and a bearing portion, extending between the first and second end portions, for supporting a cam rider arrangement. The cam rider arrangement is supported on the bearing portion of the pin element so that, in use, the reciprocating pump is cyclically loaded and unloaded as an outer surface of the cam rider arrangement interfaces with a rotating camshaft. At least one of: the bearing portion of the pin element; and/or an inner surface of the cam rider arrangement; comprises one or more recessed formations for supporting hydrodynamic lubrication between the cam rider arrangement and the pin element as the bearing portion bends during the loading cycle.

Abstract: A low pressure regulator for a high pressure fuel pump includes a standard damping orifice, providing a constant level of piston movement damping by enabling a fluid pathway between a spring chamber and a return line. The low pressure regulator also includes a further damping orifice, which is covered by the piston when discharge port holes are open, the further damping orifice providing a further, variable level of piston movement damping by providing a further fluid pathway between the spring chamber and return line. The further damping orifice is open in a hydraulic accumulator mode and closed in a regulator mode, thereby reducing pressure spikes caused by insufficient spring chamber filling.

Abstract: A low pressure regulator for a high pressure fuel pump includes a standard damping orifice, providing a constant level of piston movement damping by enabling a fluid pathway between a spring chamber and a return line. The low pressure regulator also includes a further damping orifice, which is covered by the piston when discharge port holes are open, the further damping orifice providing a further, variable level of piston movement damping by providing a further fluid pathway between the spring chamber and return line. The further damping orifice is open in a hydraulic accumulator mode and closed in a regulator mode, thereby reducing pressure spikes caused by insufficient spring chamber filling.