Methods and systems are provided for adjusting operation of fuel injectors of an internal combustion engine to reduce injector ticking noise during direct injection fuel rail pressure release. The method includes first reducing a significant part of the direct injection fuel rail pressure via a mechanical high pressure pump relief valve and only if further pressure relief is required then intermittently activating the direct injector to inject in small amount of fuel. Due to the reduced frequency of activation and small pulse-widths, the impact force transmitted from injectors to cylinder head is small thereby reducing the objectionable ticking noise.

The required fuel supply amount of an internal combustion engine is reduced by limiting the throttle opening when a high-pressure fuel pump is required to discharge fuel that exceeds the fuel delivery capacity thereof. Further, when the throttle opening is limited, the operation of a return valve, through which fuel and vapor thereof can be discharged from the high-pressure fuel pump, is prohibited. By performing the abovementioned control, a reduction in the fuel delivery amount of the high-pressure fuel pump due to the operation of the return valve is prevented when there is a possibility that the fuel deliver amount of the high-pressure fuel pump runs short and the fuel supply amount of the internal combustion engine runs short.

A high-pressure fuel pump for a fuel delivery system of an internal combustion engine includes a pressure limiting valve positioned between an outlet and an inlet of the pump. The valve includes a spring-loaded closing element and a closing body that radially holds the closing element in place, and that has a concave receiving portion configured to at least partially receive the closing element. The receiving portion has a radially outer first area with a first opening angle, and a radially inner second area with a second opening angle larger than the first opening angle. The first area and the second area are located outside of a contact region between the closing element and the closing body.

A method for controlling a high-pressure pump for the injection of fuel into a combustion engine, the high-pressure pump being connected to a camshaft of the combustion engine, wherein the high-pressure pump is controlled in a camshaft-synchronous manner by ascertaining an angular offset between the flank positions of a camshaft pulse-generating wheel and a predefinable point above the bottom dead center of a cam of the high-pressure pump on the camshaft.

A high pressure fuel pump is provided with a pumping bore and a pressure relief valve only opening to enable a return flow from the outlet conduit back to the compression chamber when the pressure in the outlet conduit exceeds a predetermined threshold. The pressure relief valve is arranged in an elongated pressure relief valve chamber extending parallel and offset to the pumping bore.

Electronic fuel injection for an internal combustion engine maintains an operator-specified air-to-fuel ratio during engine operations in high-speed, high-volume, mixed fuel applications. A microprocessor-based controller executes a program stored in memory to calculate a fuel flow value as a function of the specified air-to-fuel ratio and specified density ratio of mixed fuels. The controller outputs a control signal to a variable fuel flow relief valve and receives feedback from an engine fuel flow sensor. The controller adjusts the control signal until the feedback matches the fuel flow value. The program optimizes the fuel flow value by accounting for engine air flow, water vapor density, and dry air density effects in the calculation, based on signals received by the controller from various environmental sensors. The system has particular application in dragster engines that burn a mixture of nitromethane and methanol.

An example valve includes a piston configured to block fluid flow from a first port of the valve to a second port of the valve when the valve is in a closed position; a relief mode spring applying a first biasing force on the piston in a distal direction; a reverse flow spring applying a second biasing force on the piston in a proximal direction, wherein the reverse flow spring is weaker than the relief mode spring; and a pressure setting spring applying a third biasing force on a check element in the distal direction, causing the check element to be seated when the valve is in the closed position.

Disclosed is a method and a device for predicting the failure time of the pressure limiting valve of a high-pressure fuel pump of a motor vehicle. The method includes measuring a characteristic parameter of the pressure limiting valve each time the motor vehicle has been switched off, determining and storing a variable determined by using the measured characteristic parameter, determining the time profile of the variable determined from the characteristic parameter, predicting the future profile of the variable determined from the characteristic parameter, and comparing the predicted future profile of the variable determined from the characteristic parameter with a predetermined wear limiting value. The comparison is to predict the time at which the predicted future profile of the variable determined from the characteristic parameter reaches the predetermined wear limiting value.

A method for monitoring a pressure sensor in a direct injection system including at least one common rail, a high-pressure fuel pump, a hydraulic circuit connecting the high-pressure pump to the common rail, a passive pressure-limiting valve connected to the hydraulic circuit, configured to open once the pressure in the hydraulic circuit is greater than a threshold pressure, so as to discharge the fuel, including the steps of detecting the opening of the pressure-limiting valve, measuring the pressure P.sub.MES corresponding to the time of opening of the pressure-limiting valve and comparing the measured pressure P.sub.MES to the threshold pressure P.sub.1 in order to detect a drift in the pressure sensor.

The disclosed inlet check valve is used in a high pressure fuel pump and is comprised of a valve member integrally connected to a valve stem which is coupled to an inlet valve armature. The valve member has a stroke along an axis between an open position and a closed position. An inlet valve solenoid generates a magnetic field in an inlet valve pole to attract the inlet valve armature and move the valve member from the open position to the closed position. In the open position, the valve member contacts an inlet valve stop and a gap greater than the stroke of the valve member is defined along the axis between the inlet valve armature and the inlet valve pole. In the closed position, an inlet valve seat mates with the valve member and an armature gap remains between the inlet valve armature and the inlet valve pole.