The disclosure relates to a method for pressure regulation in a fuel high-pressure injection system having an overpressure valve, in which pressure pulsations occur which are caused by fuel being pumped into a high-pressure fuel accumulator and extracted from the high-pressure fuel accumulator. The method includes detecting pressure values of the fuel present in the high-pressure fuel accumulator. The method also includes comparing the detected pressure values with a nominal pressure value; and carrying out a pressure regulation in which the fuel pressure prevailing in the high-pressure fuel accumulator is set to the nominal pressure value. During pressure regulation, a peak pressure value of the detected pressure values is used as the actual pressure value. The disclosure also relates to a device for pressure regulation in a fuel high-pressure injection system.

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).

A method for model-based open-loop and closed-loop control of an internal combustion engine, in which method injection system setpoint values for activating the injection system control elements are calculated dependent on a setpoint torque by a combustion model, and gas path setpoint values for activating the gas path control elements are calculated by a gas path model. The combustion model is adapted during ongoing operation of the internal combustion engine. A quality measure is calculated by an optimizer dependent on the injection system setpoint values and the gas path setpoint values, the quality measure is minimized by the optimizer by varying the injection system setpoint values and gas path setpoint values within a prediction horizon. The injection system setpoint values and gas path setpoint values are set by the optimizer, based on the minimized quality measure, as being definitive for setting of the operating point of the internal combustion engine.

Method and apparatus for adjustable fuel pressure module. In accordance with an embodiment of the present invention, an apparatus for regulating fuel pressure comprises a body configured to mate to a fuel filter housing, a spring seat assembly configured to seal an opening in the fuel filter housing according to a force applied by a pressure regulating spring acting on the spring seat assembly, and a pressure regulating spring adjusting assembly mounted to the body, configured to constrain an adjustable length of the pressure regulating spring, wherein the spring is constrained between the spring seat assembly and the pressure regulating spring adjusting assembly. A force exerted upon the spring seat assembly by the pressure regulating spring corresponds to a desirable fuel pressure. The spring seat assembly is configured to unseal the opening in the fuel filter housing responsive to a fuel pressure greater than the desirable fuel pressure.

A method of testing a fuel injection system or components thereof includes running a high pressure fuel pump to provide fluid under pressure to the fuel injection system or components. The pump flow is controlled via an inlet metering valve by controlling current or voltage supplied to the inlet metering valve dependent on the power to the fuel pump.

Methods and systems are provided for vehicle direct injection fuel pump control. In one example, a method may include reducing a flow speed of fuel from a cam-driven direct injection fuel pump for at least half of a total duration of an output stroke of the fuel pump. A cam driving the fuel pump may reduce the flow speed at a first rate during a main portion of the output stroke, and the cam may reduce the flow speed at a second rate during an end ramp portion of the output stroke.

A method for operating an internal combustion engine having an injection system which has a high-pressure accumulator, high pressure in the high-pressure accumulator being controlled via a suction throttle on the low-pressure side, acting as a first pressure control element in a first high-pressure control loop. During normal operation, a high-pressure disturbance variable is produced by a pressure regulating valve on the high-pressure side, acting as an additional pressure control element, via which fuel is re-directed from the high-pressure accumulator into a fuel reservoir, the at least one pressure regulating valve being controlled, during normal operation, based on a set volumetric flow rate for the fuel to be re-directed. A temporal development of the set volumetric rate is sensed and the set volumetric flow rate is filtered, a time constant for the filtering of the set volumetric flow rate being selected as a function of the sensed temporal development.

Various embodiments include methods for operating a high-pressure pump comprising: driving a piston arranged in a compression chamber with a motor shaft; during movement of the piston toward the top dead center, closing the inlet valve so the fluid is then delivered by the piston through an outlet valve; applying a coil current to an electromagnet used to close the inlet valve during and/or after overshooting the top dead center; detecting a start time at which the coil current, on account of starting of an opening movement of the inlet valve, fulfills a predetermined change criterion; labelling a dead center rotation position of the motor shaft at which the piston is at the top dead center based at least in part on the ascertained start time; and adjusting operation of the pump based on the identified dead center rotation position.

A method for requirement-based servicing of an injector in a common-rail system in which, during ongoing operation of the engine, a current operating point is stored as a function of the rail pressure and of the fuel injection mass, and the current operating point is multiplied by a damage factor and is stored as a reference injection cycle as a function of the rail pressure as well as of the fuel injection mass. A total reference injection cycle is calculated by forming sums over the reference injection cycles, and a load factor is calculated as a function of the total reference injection cycle and the permissible injection cycles, and the load factor is set as decisive for the servicing recommendation of the injector.

Embodiments of a gaseous or dual fuel electronic pressure regulation system (EPRS) for a multipoint fuel injection engine are described herein. Additionally, embodiments of a method for controlling the EPRS are provided. In particular, the EPRS employs an electronic pressure regulator (EPR) capable of accurately determining and controlling the mass flow of gaseous fuel into a fuel rail so as to avoid pressure droop and over- and under-pressurization of the gas admission valves (GAVs). By using the EPRS described above, mass flow is able to be distributed to the downstream manifold or engine cylinders very accurately, and the GAVs are able to be driven simultaneously in a pressure/pulse duration that is optimal for accurate and repeatable operation.