Abstract: In the low pressure zone (10) of a fuel injection system a fuel pressure damper (12) is provided which dampens pressure variations, especially such pressure variations that are caused by operation of a high-pressure fuel pump (16) mounted downstream of the low pressure zone (10). In the low pressure zone (10), the pressure profile is detected by means of a pressure sensor (14). The high-frequency components of the pressure profile detected by the pressure sensor (14) can be used to ascertain whether the fuel pressure damper (12) functions properly.

Abstract: The invention makes the identification of defects possible in a fuel injection system comprising a fuel accumulator, a continuously operating high-pressure pump and a fuel pressure control valve. By evaluating the high-frequency portion of the fuel pressure course in the fuel accumulator, it can be indicated with a high probability which of the components are defective whereby this is assisted, in particular, by additional evaluations performed during a diagnostic method.

Abstract: A high-pressure pump is provided in order to supply fuel to the fuel rail of a common rail injection system in an internal combustion engine. The input-side control valve of the pump is closed during the pumping cycle in order to separate the inner chamber of the pump from the low-pressure side. According to the invention, the valve control pulse, by which means the control valve is closed, is active when the pressure wave generated by the upward movement of the pump plunger hits the control valve. The closing of the control valve is assisted by the impact of the pressure wave.

Abstract: An injection system for an internal combustion engine comprises a pump (1), a pressure accumulator (3), a sensor (7) for detecting the pressure in the pressure accumulator (3), a control valve (2) and a control or regulation unit (8). The control or regulation unit controls the pressure in the pressure accumulator (3) by opening or closing a connection to a low-pressure area (6). The control or regulation unit has an emergency operation function, which operates in such a way that when an error occurs in the regulator circuit, the control valve adopts the open position.

Abstract: An injection system for an internal combustion engine comprises a pump (1), a pressure accumulator (3), a sensor (7) for detecting the pressure in the pressure accumulator (3), a control valve (2) and a control or regulation unit (8). The control or regulation unit controls the pressure in the pressure accumulator (3) by opening or closing a connection to a low-pressure area (6). The control or regulation unit has an emergency operation function, which operates in such a way that when an error occurs in the regulator circuit, the control valve adopts the open position.