Pressure sensor of a high-pressure injection system, control device, high-pressure injection system, and motor vehicle

1. A method for checking a pressure sensor of a high-pressure injection system of an internal combustion engine of a motor vehicle, the method comprising:

moving a piston toward a top dead center within a compression chamber of a high-pressure pump in successive pump cycles during an expulsion phase, expelling a fluid from the compression chamber;

during movement of the piston toward top dead center, closing an inlet valve using a control device by applying current to an electromagnet, wherein the expelled fluid generates a fluid pressure downstream of the outlet valve in a high-pressure region;

generating a pressure signal using the pressure sensor arranged downstream of the outlet valve;

applying a measurement current to the electromagnet using the control device when the inlet valve is closed;

while the piston moves away from top dead center, detecting an opening position of the piston at which an opening movement of the inlet valve begins on the basis of a predetermined change with respect to time of the measurement current;

checking whether a value sequence of the ascertained opening positions over multiple pump cycles satisfies a predetermined discrepancy criterion with regard to the sensor signal; and

if the discrepancy criterion is satisfied, generating a fault signal relating to the pressure sensor.

2. The method as claimed in claim 1 , wherein the discrepancy criterion corresponds to an indication based on the value sequence that the opening position shifts away from the top dead center and thus a rising pressure profile of the fluid pressure and the sensor signal of the pressure sensor deviates from the pressure profile by more than a predetermined tolerance value.

3. The method as claimed in claim 1 , further comprising indicating a delta step change with the control device if a difference of the sensor signal relative to the value sequence of greater than a predetermined delta value is identified on the basis of a difference signal.

4. The method as claimed in claim 3 , further comprising counting with the control device how often a delta step change is identified in succession; and

wherein the discrepancy criterion comprises a count greater than a predetermined minimum number.

5. The method as claimed in claim 1 , wherein the discrepancy criterion indicates a rotational speed of an engine shaft driving the piston greater than a predetermined operating value.

6. The method as claimed in claim 1 , wherein the discrepancy criterion indicates a volume flow of the fluid greater than a predetermined minimum delivery value.

7. The method as claimed in claim 1 , further comprising ascertaining the value sequence and checking the discrepancy criterion if, upon a start of the internal combustion engine, the sensor signal has a constant profile in accordance with a predetermined constancy criterion.

8. The method as claimed in claim 1 , further comprising setting a current intensity of the measurement current lower than is provided for the closing of the inlet valve.

9. The method as claimed in claim 1 , wherein the predetermined change with respect to time of the measurement current for the detection of the opening movement indicates a predetermined mean value of the measurement current increases.

10. The method as claimed in claim 1 , wherein ascertaining the opening position includes monitoring a rotational position sensor of the internal combustion engine.

11. A control device for a high-pressure injection system of an internal combustion engine of a motor vehicle, the control device comprising:

a processor; and

a memory storing a set of instructions, the set of the instructions, when loaded and executed by the processor, causing the processor to:

close an inlet valve of a high-pressure pump of the high-pressure injection system in a manner dependent on a sensor signal of a pressure sensor;

move a piston toward a top dead center within a compression chamber of a high-pressure pump in successive pump cycles during an expulsion phase, expelling a fluid from the compression chamber;

during movement of the piston toward top dead center, close an inlet valve using a control device by applying current to an electromagnet, wherein the expelled fluid generates a fluid pressure downstream of the outlet valve in a high-pressure region;

generate a pressure signal using the pressure sensor arranged downstream of the outlet valve;

apply a measurement current to the electromagnet using the control device when the inlet valve is closed;

while the piston moves away from top dead center, detect an opening position of the piston at which an opening movement of the inlet valve begins on the basis of a predetermined change with respect to time of the measurement current;

check whether a value sequence of the ascertained opening positions over multiple pump cycles satisfies a predetermined discrepancy criterion with regard to the sensor signal; and

if the discrepancy criterion is satisfied, generate a fault signal relating to the pressure sensor.