Various methods and systems are provided for health assessments of a fuel system. In one example, a fuel system includes a high-pressure fuel pump operable to increase fuel pressure from a first pressure to a second pressure, a common fuel rail fluidly coupling the high-pressure fuel pump to a plurality of fuel injectors each of which is operable to inject fuel to individual cylinders of an engine, a pressure sensor operable to detect a pressure of fuel at the common fuel rail, and a controller operable to diagnose a condition of the high-pressure fuel pump based on output from the pressure sensor.

A high pressure fuel pump includes an inlet metering valve arranged to control a quantity of fuel delivered to the pumping chamber during retracting motion of the pumping plunger. The inlet metering valve includes a metering valve member movable between a closed position and an open position, movement of the metering valve member from the closed position to the open position defining a variable flow area that increases as the metering valve member moves from the closed position toward the open position. An actuator piston in an actuator bore is exposed to pressure in the common rail. The actuator piston is biased toward a first position corresponding to low pressure in the common rail and movable toward a second position corresponding to maximum pressure in the common rail. The actuator piston includes a valve stop that determines a metering position of the metering valve member.

A high pressure fuel pump includes an inlet metering valve arranged to control a quantity of fuel delivered to the pumping chamber during retracting motion of the pumping plunger. The inlet metering valve includes a metering valve member movable between a closed position and an open position, movement of the metering valve member from the closed position to the open position defining a variable flow area that increases as the metering valve member moves from the closed position toward the open position. An actuator piston in an actuator bore is exposed to pressure in the common rail. The actuator piston is biased toward a first position corresponding to low pressure in the common rail and movable toward a second position corresponding to maximum pressure in the common rail. The actuator piston includes a valve stop that determines a metering position of the metering valve member.

Disclosed is a metal diaphragm damper that is hard to fracture even when repeated stress is applied thereto. A disk-shaped metal diaphragm damper is provided with diaphragms each having a deformable portion provided at the center and an outer circumferential fixation portion formed by outer circumferential rims of the diaphragms and that is filled with gas. The deformable portion has a third curved portion located at the radially outward side thereof and formed to be bulged; a first curved portion located radially inward of the third curved portion and formed to be bulged out; and a second curved portion located between the third curved portion and the first curved portion. The second curved portion includes at least one curved wall part which is formed to be dented in.

Methods and systems for operating an engine that includes two fuel pumps are described. In one example, a first fuel pump may be activated or remain activated in response to an engine shutdown request so that a second fuel pump may be cooled before the first fuel pump is deactivated in response to the engine shutdown request.

Methods and systems for operating an engine that includes two fuel pumps are described. In one example, a first fuel pump may be activated or remain activated in response to an engine shutdown request so that a second fuel pump may be cooled before the first fuel pump is deactivated in response to the engine shutdown request.

A high pressure fuel pump includes an inlet metering valve arranged to control a quantity of fuel delivered to the pumping chamber during retracting motion of the pumping plunger. The inlet metering valve includes a metering valve member movable between a closed position and an open position, movement of the metering valve member from the closed position to the open position defining a variable flow area that increases as the metering valve member moves from the closed position toward the open position. An actuator piston in an actuator bore is exposed to pressure in the common rail. The actuator piston is biased toward a first position corresponding to low pressure in the common rail and movable toward a second position corresponding to maximum pressure in the common rail. The actuator piston includes a valve stop that determines a metering position of the metering valve member.

A high pressure fuel pump includes an inlet metering valve arranged to control a quantity of fuel delivered to the pumping chamber during retracting motion of the pumping plunger. The inlet metering valve includes a metering valve member movable between a closed position and an open position, movement of the metering valve member from the closed position to the open position defining a variable flow area that increases as the metering valve member moves from the closed position toward the open position. An actuator piston in an actuator bore is exposed to pressure in the common rail. The actuator piston is biased toward a first position corresponding to low pressure in the common rail and movable toward a second position corresponding to maximum pressure in the common rail. The actuator piston includes a valve stop that determines a metering position of the metering valve member.

Unclogging group for unclogging a filter of a pumping group for pumping diesel to an internal combustion engine, the unclogging group comprising: —a metering unit comprising an electromagnetic head and a control valve for controlling the diesel flow; —a filter associated with the control valve made at least in part of metallic material; —a temperature sensor for measuring the ambient temperature; —a control unit coupled to the temperature sensor; —an electrical circuit controlled by the control unit for supplying electrical current to the filter; wherein the control unit is configured so once received the starting input of the pumping group it compares the temperature measured by the temperature sensor with a threshold value, and if the temperature measured by the temperature sensor is less than the threshold value the control unit commands a delay of the starling of the pumping group of a period wherein the control unit supplies electrical current to the electrical circuit connected to the filter.

Unclogging group for unclogging a filter of a pumping group for pumping diesel to an internal combustion engine, the unclogging group comprising: —a metering unit comprising an electromagnetic head and a control valve for controlling the diesel flow; —a filter associated with the control valve made at least in part of metallic material; —a temperature sensor for measuring the ambient temperature; —a control unit coupled to the temperature sensor; —an electrical circuit controlled by the control unit for supplying electrical current to the filter; wherein the control unit is configured so once received the starting input of the pumping group it compares the temperature measured by the temperature sensor with a threshold value, and if the temperature measured by the temperature sensor is less than the threshold value the control unit commands a delay of the starling of the pumping group of a period wherein the control unit supplies electrical current to the electrical circuit connected to the filter.