A high pressure fuel pump includes: a pump body that forms a suction passage and a pressurizing chamber and slidably supports a plunger; and a control valve that opens a connection between the suction passage and the pressurizing chamber in a suction stroke, during which the plunger is driven toward a suction side for suctioning fuel into the pressurizing chamber, while the control valve controls closing timing, at which the connection between the suction passage and the pressurizing chamber is closed by the control valve in a delivery stroke, during which the plunger is driven toward a delivery side for delivering the fuel out of the pressurizing chamber. The pump body forms a release passage that is communicated with the suction passage. The release passage relieves the fuel, which is pressurized by the plunger, from the pressurizing chamber before the closing timing during the delivery stroke.

Methods are provided for controlling a direct injection fuel pump, wherein a solenoid spill valve is energized and de-energized according to certain conditions. A control strategy is needed to operate the direct injection fuel pump outside regions where pump operation may be variable and inaccurate, where the regions may be characterized by smaller pump commands as well as smaller displacement volumes. To maintain a suitable range of pump commands and displacements while operating outside the low accuracy regions, a method is proposed that involves clipping calculated pump commands when the calculated pump commands lie within the low accuracy regions.

The invention relates to a fluid conveyance system for a fluid, comprising a low-pressure conveyance system having a low-pressure pump (2) and a high-pressure conveyance system having a high-pressure pump (8), which are connected by means of a connecting line, wherein the fluid conveyance system has a pressure damper (19). According to the invention, a fluid conveyance system is provided, by means of which a pulsation of the fluid caused by flow-rate waves or pressure waves in the fluid is damped. This is achieved in that the pressure damper (19) is arranged in the lower-pressure conveyance system and is a hydraulic pressure damper (19). Said hydraulic damper (19) has a piston (21) arranged in a cylinder (20), which piston can be moved against the force of a compression spring (23) and the vapor pressure present in a compression-spring chamber (22) accommodating the compression spring.

A fuel injection pump (1) for a diesel engine (30), including: a control rack (20) an in a rack chamber (5) formed between a pump head (3) and a pump housing (2), and configured to adjust a fuel injection amount; a transmission shaft (49) rotatably supported by a transmission shaft hole (2C) formed in the pump housing; and a lubricating oil passage (2D) formed in the pump housing, and configured to pressure-feed lubricating oil between the transmission shaft and the transmission shaft hole. The transmission shaft has an oil passage (40) therein through which passage the lubricating oil pressure-fed to the lubricating oil passage partially passes, a first opening of the oil passage is communicated with the lubricating oil passage, and a second opening (42A) of the oil passage is formed on the outer circumferential surface of an upper portion of the transmission shaft, nearby the control rack.

A lubricity estimation device is applied to a fuel supply system that supplies a fuel to an internal combustion engine, and includes a mixing ratio estimation unit and a lubrication index calculation unit. The mixing ratio estimation unit estimates the mixing ratio of each of plural types of molecular structures included in the fuel. The lubrication index calculation unit calculates a lubrication index, representing the lubricity of an outer peripheral portion S1 of the piston of a fuel pump and an outer peripheral portion of the valve body of a fuel injection valve by the fuel, based on the mixing ratio estimated by the mixing ratio estimation unit.

The invention relates to a high pressure pump for a fuel injection system, in particular a common rail injection system, comprising a housing part (1) with a bore (2), in which a pump piston (3) is received such that it can be moved with a reciprocating movement, which pump piston (3) is supported via a tappet assembly (4) on a cam (5) or eccentric and delimits a pump working chamber (6) in the axial direction, which pump working chamber (6) can be filled with fuel via an upstroke valve (7) which is integrated into the high pressure pump. According to the invention, a feed bore (8) is configured in the housing part (1) in order to supply the upstroke valve (7) with fuel, which feed bore (8) is connected to a bore (11) of a further housing part (12), which bore (11) connects a pump interior chamber (9) and a tappet chamber (10).

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.

A lubricated high pressure fuel pump assembly is provided, comprising a fuel pump, a sealed enclosure and a pump lubrication circuit. The fuel pump includes a pump drive shaft via which the fuel pump is configured to be mechanically driven. The sealed enclosure is configured to surround a first portion of the pump drive shaft, wherein the first portion is exterior to the fuel pump. The pump lubrication circuit comprises a lubricant reservoir and a lubricant pump configured to pump lubricant from the lubricant reservoir to the pump drive shaft. The sealed enclosure is configured to prevent fluid leakage from the fuel pump via the first portion of the pump drive shaft and the lubricant reservoir is configured to collect the lubricant from the pump drive shaft, such that the lubricant is retained within the lubricated high pressure fuel pump assembly.

Systems and methods for diagnosing and operating an engine with a fuel pump that supplies fuel to a fuel injector that may be temporarily deactivated are described. In one example, injection of fuel may commence in response to a level of lubrication of a fuel pump. The system and methods may extend fuel pump life in systems where fuel injection may be deactivated.

A pump device for an internal combustion engine, having a high-pressure fuel pump for supplying fuel to a first injection device, having at least one low-pressure inlet, via which the fuel is fed to the high-pressure fuel pump from a low-pressure fuel pump, having at least one low-pressure outlet for conducting the fuel conveyed by the low-pressure fuel pump and fed via the low-pressure inlet to the high-pressure fuel pump out of the high-pressure fuel pump, and having at least one low-pressure port, for conducting fuel conveyed by the low-pressure fuel pump to a second injection device. At least one mixing region mixes the fuel flowing through the low-pressure outlet with fuel fed to the mixing region from the low-pressure fuel pump upstream of the high-pressure fuel pump. The low-pressure port is fluidically connected to the mixing region, and the low-pressure inlet is supplied with fuel from the mixing region.