A method for determining the load status of a filter mounted in a fuel supply system, comprising a fuel supply pump and a control unit for controlling the fuel supply pump, the time curve of the rotational speed of the fuel supply pump being detected over a predetermined period of time, and at least one value of the time curve of the rotational speed and its associated detection time being compared with a comparative value stored in a control unit

A fuel injection control device is adapted for a fuel injection system including an injector and a high-pressure pump that raises pressure of fuel and supplies the fuel to the injector. The fuel injection control device includes a selecting unit for selecting by which one of full lift injection and partial injection to inject fuel, and a pump control unit for controlling operation of the high-pressure pump such that a pressure of fuel supplied to the injector coincides with a target pressure. The selecting unit selects the partial injection when a required injection quantity of fuel is equal to or smaller than a partial maximum injection quantity. A fuel injection system includes the fuel injection control device, the injector, and the high-pressure pump.

A method is disclosed of controlling operation of a fuel injector in response to measuring a quantity of fuel injected by the fuel injector from a fuel accumulator to an engine cylinder during operation of a fuel pump that delivers fuel to the accumulator, comprising: determining an average pressure of the fuel accumulator during a first time period before a fuel injection event; predicting a mass of fuel delivered to the fuel accumulator during a pumping event (Q.sub.pump); determining an average pressure of the fuel accumulator during a second time period after the fuel injection event; estimating a leakage of fuel; computing the injected fuel quantity by adding the average pressure during the first time period to Q.sub.pump, and subtracting the average pressure during the second time period and the leakage; and using the computed injected fuel quantity to control operation of the fuel injector.

A storage device is configured to store a first mapping that receives, as an input, a first input variable including a cam phase variable on present and past phases of a cam, and output a pulsating variable on a pulsating component. The execution device is configured to acquire the first input variable and estimate the pulsating variable by applying the acquired first input variable to the first mapping. Therefore, it is possible to estimate the pulsating variable without providing a low-pressure fuel pressure sensor by estimating a fuel pressure variable by applying the first input variable to the first mapping.

A method and a device for determining the injection quantity or the injection rate of a fluid which is transported to an injector through a hydraulic line and is injected into a reaction space by the injector. The fluid pressure in the hydraulic line is measured by a pressure sensor, the fluid pressure at the injector is determined using the pressure measured by the pressure sensor and a stored transmission function of the hydraulic line, and the injection quantity or the injection rate of the fluid injected by the injector is determined using the fluid pressure determined at the injector.

A fuel pressure estimation system estimates a fuel pressure variable on a fuel pressure in a supply pipe for an engine apparatus including an engine having a fuel injection valve, and a fuel supply device having a fuel pump that supplies the fuel in a fuel tank to the supply pipe, and includes a storage device and an execution device. The storage device stores a first mapping that receives, as an input, first input variables including a pump variable, a consumption flow rate variable on a consumption flow rate of the fuel, and a property variable on a property of the fuel, and outputs the fuel pressure variable. The execution device acquires the first input variables and estimates the fuel pressure variable by applying the first input variables to the first mapping.

A dual-fuel supply system (100) for direct injection for engines of heavy vehicles, comprising: a supply line of a combustible liquid (160); a supply line of a combustible gas (170); a plurality of injectors (150) in fluid communication with the supply line of the combustible liquid (160) and with the supply line of the combustible gas (170); a pressure regulator device (1) for regulating the combustible gas; an electronic control unit (ECU) configured to control the supply of combustible liquid and of the combustible gas to the injectors (150), the electronic control unit (ECU) being configured to control the pressure regulator device (1) to track a reference pressure (p.sub.target) according to a feedback logic.

A fuel pump pressure-feeds fuel to an accumulation container that accumulates high-pressure fuel. A fuel injection valve injects high-pressure fuel accumulated in the accumulation container to an internal combustion engine. A fuel pressure sensor detects a fuel pressure in the accumulation container. A fuel pressure acquisition unit acquires the fuel pressure detected with the fuel pressure sensor. A reference computation unit computes a required injection quantity and an injection start timing based on an operation state of the internal combustion engine at a predetermined reference computation timing, which is set for each combustion cycle of the internal combustion engine, and further to compute an injection time period based on a fuel pressure acquired by the fuel pressure acquisition unit at the reference computation timing. A correction unit corrects the injection time period based on the fuel pressure acquired by the fuel pressure acquisition unit at the injection start timing.

The invention relates to a method for controlling gaseous fuel pressure in an accumulator (12) of a fuel system (10) for a combustion engine (102) of a vehicle (100), wherein the method comprises the steps of: determining a nominal amount of gaseous fuel to be introduced into the accumulator; introducing less gaseous fuel into the accumulator than the determined nominal amount by reducing or closing an inlet valve (24), which inlet valve is adapted to regulate input of gaseous fuel to the accumulator; and while the inlet valve is reduced or closed, performing at least one injection of gaseous fuel coming from the accumulator into at least one combustion chamber (104a-f) of the combustion engine by at least one injector (14a-f) of the fuel system, which at least one injection contributes to combustion in the combustion engine, thereby reducing pressure in the accumulator. The invention also relates to a corresponding fuel system (10).

An internal combustion engine with at least one combustion chamber, at least one fuel delivery line for the delivery of fuel to at least one combustion chamber, and at least one differential pressure control valve for controlling the pressure in the at least one fuel delivery line. The at least one differential pressure control valve is configured to perform a valve opening or valve closing movement based on a pressure difference between the at least one fuel delivery line and a reference volume having a reference pressure. The internal combustion engine further includes at least one pressure relief valve, separate from the at least one differential pressure control valve, and configured to open to cause a pressure relief in the reference volume and a decrease in the reference pressure if a drop occurs in the power to be performed by the internal combustion engine.