A fuel system is disclosed for use with an engine, including a fuel injector assembly fluidly coupled with a low-pressure fuel conduit, an accumulator, and a cap within an opening in the accumulator. The fuel injector assembly may be structured to draw in low-pressure fuel, pressurize the fuel, and store the pressurized fuel in the accumulator for injection to a combustion chamber. The cap has a pressure sensor and a pressure relief valve therein, and drains fuel leaked past fluid seals between the cap and each of the pressure sensor, the pressure relief valve, and the accumulator by way of a common drain line.

A method for checking the operation of a high-pressure fuel supply unit for an internal combustion engine, consisting in driving a high-pressure fuel injection pump by a starter, and after the engine is synchronised and fuel injection into the cylinders is shut off, in defining an initial base pressure in a high-pressure rail, in activating the injection pump by issuing successive timing and angle-setting commands, on the basis of the initial pressure, and in comparing the first pressure and the second pressure obtained in the rail by these timing and angle-setting commands, and/or by comparing at least one of the pressures with a reference pressure in order to check the operation of the high-pressure fuel supply unit for the internal combustion engine.

A control device is applied for an internal combustion engine which is provided with a high-pressure fuel pump driven by a driving shaft of the internal combustion engine to discharge a fuel pressurized in a pressurizing chamber, an accumulator accumulating a high-pressure fuel discharged from the high-pressure fuel pump, and a relief valve which is opened when a fuel pressure in the accumulator is higher than a specified pressure in order to return the fuel in the accumulator to a specified chamber where a fuel has lower pressure than a fuel in the pressurizing chamber. An idle speed of the internal combustion engine is increased to a specified speed when the fuel pressure in the accumulator has been higher than a determination pressure, which is lower than the specified pressure, for a first period or longer.

A control system includes an internal combustion engine and a control device. The internal combustion engine includes a pressurization device. The pressurization device includes a housing having a cylindrical shape, a piston, a pressurization chamber, a piston chamber, a pressurization control chamber, and a switching device configured to selectively connect the pressurization control chamber with a high pressure fuel channel or a low pressure fuel channel. The control device estimates the temperature of the low pressure fuel channel. When the estimated temperature of the low pressure fuel channel is lower than the temperature of the pressurization device, and the temperature of the pressurization device is higher than a predetermined cooling request temperature, the control device controls the switching device to connect the pressurization control chamber with the low pressure fuel channel.

A method for identifying a source of high pressure leakage of a fuel system of an engine comprising determining pressure decay values at a first pressure and at a second pressure and identifying the source of high pressure leakage based on the pressure decay values at each pressure.

A method may comprise: positioning a pressure control valve (PCV) at an outlet of a fuel rail; positioning a volume control valve (VCV) at an inlet of a high pressure pump; and in response to an exhaust particulate matter (PM) level deviating from a target PM level, adjusting a fuel ratio of a first fuel and a second fuel delivered to an engine, and opening one of the PCV and the VCV. In this way, the fuel oxygen content may be adjusted to maintain a PM at or below a target level without a DPF over a broad range of engine designs and operating conditions, while maintaining fuel economy.

An electrically driven solenoid coupled to a spring-operated valve, regulates pressure in an accumulator by opening when a predefined threshold pressure in a pressure accumulator is exceeded. The solenoid provides an assistive force to a spring-closed valve, reducing the amount of pressure required to open the valve responsive to the amount of current provided to the solenoid. The threshold pressure at which the valve opens is thus determined by the amount of current provided to the solenoid. Increasing the current decreases the threshold pressure; decreasing the current increases the threshold pressure.

A fuel injection system is provided with a pressure accumulator accumulating a high pressure fuel, a fuel pump supplying the high pressure fuel to the pressure accumulator, a fuel injector injecting the high pressure fuel, and a fuel pressure sensor detecting a fuel pressure in a fuel passage between the pressure accumulator and an injection port of the fuel injector. An ECU includes a fuel pressure obtaining portion which obtains the fuel pressure detected by the fuel pressure sensor, a differential value calculating portion which differentiates the fuel pressure obtained by the fuel pressure obtaining portion so as to calculate a fuel pressure differential value, and an end timing calculating portion which calculates an injection end timing at which the fuel injector terminates a fuel injection.

Provided is a method for diagnosing unintended fuelling from one or more fuel injectors of a multi cylinder internal combustion engine during engine operation. Pressurized fuel is intended to be distributed by means of said fuel injectors from said accumulator tank to the cylinders for combustion. An oxidation catalyst is arranged downstream said cylinders. The method comprises: determining the pressure in the fuel accumulator tank and whether said pressure is decreasing; and determining whether the actual amount of fuel provided by the pump unit exceeds the demanded amount of fuel. The method further comprises the steps of: determining whether the temperature associated with the oxidation catalyst is above a certain level and/or determining whether the air/fuel ratio is below a certain level and/or determining whether an amount of particulate matter is above a certain level; and confirming an unintended fuelling based on the determined conditions.

A method for operating an internal combustion engine with a high pressure accumulator for a fuel injection system, includes the steps of: monitoring, in a time-dependent manner, a high pressure in the fuel injection system; conducting a check, at a high pressure-dependent starting time point, as to whether a continuous injection detection is to be carried out; and checking whether a high-pressure oscillation has occurred within an oscillation time interval prior to a starting time.