A pump unit for feeding fuel, in particular diesel fuel, to an internal-combustion engine; the pump unit comprising a head (2) inside which a cylinder (3) is formed along an axis; a pumping piston (4) housed inside the cylinder and comprising a head portion (24) inside the cylinder and an opposite foot portion (23) projecting outside the cylinder; wherein the piston is slidable inside the cylinder in a reciprocating manner between a first position and a second position where the foot projects from the cylinder by a greater or smaller amount respectively; and wherein the outer surface of the piston comprises a portion (16) with a surface finish so as to have less friction and a greater lubricant-retaining capacity than the remainder of the outer surface of the piston; the portion extending along the axis between the head of the piston and a first intermediate point (17) in the first position of the piston, the first intermediate point being inside the cylinder.

In a high pressure fuel supply system, a variable speed motor asynchronously actuates a pumping piston with a drive mechanism including a circular cam with cam roller, having an axis that is offset from the axis of the cam drive shaft. A rolling or sliding cam follower is rigidly connected to the piston, and a piston retainer is operatively connected among the piston, the cam follower and the cam roller. As the cam shaft rotates, the cam roller rotates eccentrically relative to the cam shaft while maintaining contact with the cam follower, thereby reciprocating the follower and the piston along the actuation axis, in corresponding charging and pumping strokes of the piston.

A device for supplying lubricant for a fuel injection nozzle for injecting compressed natural gas (CNG) into an internal combustion engine is provided. The device includes a lubricant reservoir for supplying lubricant and having a feed pressure supply apparatus for applying a feed pressure to lubricant which is stored in the lubricant reservoir, where a feed pressure valve for setting the feed pressure is provided between the feed pressure supply apparatus and the lubricant reservoir, and a lubricant metering valve for metering the lubricant supply is provided between the lubricant reservoir and the fuel injection nozzle, where the lubricant is fed to the lubricant reservoir from an oil gallery of the internal combustion engine.

A fuel injection pump for a diesel engine, including: a control rack an in a rack chamber formed between a pump head and a pump housing, and configured to adjust a fuel injection amount; a transmission shaft rotatably supported by a transmission shaft hole formed in the pump housing; and a lubricating oil passage 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 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 of the oil passage is formed on the outer circumferential surface of an upper portion of the transmission shaft, nearby the control rack.

The invention relates to a roller tappet (1) for a piston pump, in particular for a high-pressure fuel pump, for supporting a pump piston (2) which can move in a reciprocating motion on a cam (3) or eccentric of a drive shaft (4), comprising a tappet body (5) with an end-side recess (6) and two radial bores (7) which lie diametrically opposite one another at the recess (6) and receive a pin (8), on which a roller (10) is rotatably mounted directly or indirectly via a bearing bush (9), wherein at least one radially or obliquely running feed bore (12) is configured in the tappet body (5) in order to supply a lubricating medium to a radial bearing gap (11) which is configured between the roller (10) and the pin (8) or between the roller (10) and the bearing bush (9), which feed bore (12) opens into the recess (6) in the region of an axial bearing gap (13) between the roller (10) and the tappet body (5). According to the invention, the feed bore (12) is connected to an arcuately running lubricating duct (14) which is configured in a surface (15) of the tappet body (5), which surface (15) delimits the axial bearing gap (13). Furthermore, the invention relates to a piston pump comprising a roller tappet (1) of said type.

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 cam follower roller device provides a tappet body, a pin mounted into the tappet body, and a roller mounted on the pin and provided with an outer surface and with end faces, axially delimiting the outer surface. At least one lubricant supply through-hole is formed into the thickness of the tappet body and locally faces an edge of the roller delimited between the outer surface and one of the end faces.

A fuel injection pump for a diesel engine, including: a control rack arranged in a rack chamber formed between a pump head and a pump housing, and configured to adjust a fuel injection amount; a transmission shaft rotatably supported by a transmission shaft hole formed in the pump housing; and a lubricating oil passage 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 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 of the oil passage is formed on the outer circumferential surface of an upper portion of the transmission shaft, nearby the control rack.

A pump unit for feeding fuel, in particular diesel fuel, to an internal-combustion engine; the pump unit comprising a head (2) inside which a cylinder (3) is formed along an axis; a pumping piston (4) housed inside the cylinder and comprising a head portion (24) inside the cylinder and an opposite foot portion (23) projecting outside the cylinder; wherein the piston is slidable inside the cylinder in a reciprocating manner between a first position and a second position where the foot projects from the cylinder by a greater or smaller amount respectively; and wherein the outer surface of the piston comprises a portion (16) with a surface finish so as to have less friction and a greater lubricant-retaining capacity than the remainder of the outer surface of the piston; the portion extending along the axis between the head of the piston and a first intermediate point (17) in the first position of the piston, the first intermediate point being inside the cylinder.

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.