Method for operating an injection system of an internal combustion engine, an injection system for an internal combustion engine, and an internal combustion engine including an injection system

An injection system for an internal combustion engine, the injection system comprising:

• at least one injector;
• a high pressure pump;
• a fuel reservoir;
• a high pressure accumulator, which, on the one hand, is connected fluidically with the at least one injector and, on the other hand, is connected via the high pressure pump with the fuel reservoir;
• a suction throttle allocated to the high pressure accumulator as a first pressure regulating element;
• at least one pressure control valve via which the high pressure accumulator is fluidically connected with the fuel reservoir;
• and
• a control unit which is operatively connected with the at least one injector, the suction throttle, and the at least one pressure control valve, the control unit being arranged to carry out a method for operating the injection system of the internal combustion engine, the method including the steps of:
• providing that the injection system includes a high pressure accumulator;
• regulating a high pressure in the high pressure accumulator in a normal operation by way actuating a low pressure-side suction throttle;
• regulating the high pressure in the high pressure accumulator in a first operating mode of safety operation by way of actuating at least one high pressure-side pressure control valve;
• carrying out a switchover from the normal operation into the first operating mode of safety operation if the high pressure in the high pressure accumulator one of reaches and exceeds a first limit pressure value;
• and
• carrying out a switchover from the first operating mode of safety operation into the normal operation if, starting from above a setpoint pressure value, the high pressure in the high pressure accumulator one of reaches and undershoots the setpoint pressure value, the setpoint pressure value being lower than the first limit pressure value.

An internal combustion engine, comprising:

• an injection system including:
• at least one injector;
• a high pressure pump;
• a fuel reservoir;
• a high pressure accumulator, which, on the one hand, is connected fluidically with the at least one injector and, on the other hand, is connected via the high pressure pump with the fuel reservoir;
• a suction throttle allocated to the high pressure accumulator as a first pressure regulating element;
• at least one pressure control valve via which the high pressure accumulator is fluidically connected with the fuel reservoir;
• and
• a control unit which is operatively connected with the at least one injector, the suction throttle, and the at least one pressure control valve, the control unit being arranged to carry out a method for operating the injection system of the internal combustion engine, the method including the steps of:
• providing that the injection system includes a high pressure accumulator;
• regulating a high pressure in the high pressure accumulator in a normal operation by way actuating a low pressure-side suction throttle;
• regulating the high pressure in the high pressure accumulator in a first operating mode of safety operation by way of actuating at least one high pressure-side pressure control valve;
• carrying out a switchover from the normal operation into the first operating mode of safety operation if the high pressure in the high pressure accumulator one of reaches and exceeds a first limit pressure value;
• and
• carrying out a switchover from the first operating mode of safety operation into the normal operation if, starting from above a setpoint pressure value, the high pressure in the high pressure accumulator one of reaches and undershoots the setpoint pressure value, the setpoint pressure value being lower than the first limit pressure value.