Method for monitoring a fuel supply system of an internal combustion engine and internal combustion engine for carrying out such a method

1. A method for monitoring a fuel supply system in an internal combustion engine, the method comprising the steps of:

recording a first pressure value in the fuel supply system in a region of the fuel supply system associated with a pre-filter and upstream of a low pressure pump;

recording a second pressure value in the fuel supply system downstream of the low pressure pump in a region of the fuel supply system associated with a primary filter;

monitoring the first pressure value and the second pressure value for an error state of the fuel supply system; and

recognizing the error state only if the error state is plausible on a basis of both the first pressure value and the second pressure value.

2. The method according to claim 1 , wherein, if one of the first pressure value and the second pressure value indicates the error state in the fuel supply system, the error state is verified on a basis of the other one of the first pressure value and the second pressure value, wherein the error state is accepted only if a verification returns a positive result.

3. The method according to claim 1 , wherein the error state is detected only if the error state can be clearly assigned to one of the first pressure value and the second pressure value.

4. The method according to claim 1 , wherein as the first pressure value and as the second pressure value respectively, a chronological pressure value progression is recorded, wherein the chronological pressure value progression is monitored for changes.

5. The method according to claim 1 , wherein for the first pressure value a local pressure is detected, wherein the second pressure value is detected as differential pressure.

6. The method according to claim 1 , wherein at least one of:

a) a fuel temperature value is detected, wherein the error state is recognized only if the error state is also plausible on a basis of the fuel temperature value; and

b) a load point of the internal combustion engine is detected, wherein the error state is detected only if the error state is also plausible on a basis of the load point of the internal combustion engine that is detected.

7. The method according to claim 1 , wherein if at least one of the first pressure value and the second pressure value indicates the error state in the fuel supply system, the error state is checked for plausibility on a basis of a further chronological development of at least one of the first pressure value and the second pressure value.

8. The method according to claim 1 , wherein on a basis of the first pressure value and the second pressure value, the pre-filter and the primary filter are monitored for the error state.

9. The method according to claim 1 , wherein a filter breakdown at one of the pre-filter and the primary filter is detected if only a pressure value assigned to a respective one of the pre-filter and the primary filter suggests the filter breakdown, wherein the filter breakdown is not detected if the first pressure value and the second pressure value indicate the filter breakdown.

10. The method according to claim 1 , wherein the fuel supply system is used to supply a plurality of the internal combustion engine, wherein the error state is checked for plausibility via at least two of the internal combustion engine of the plurality of the internal combustion engine.

11. The method according to claim 1 , wherein at least one further component is monitored for a filter state on a basis of the first pressure value and the second pressure value, wherein the further component is selected from a group consisting of: the low pressure pump, a control valve, a suction throttle, and a high pressure pump.

12. An internal combustion engine, comprising:

a fuel supply system configured for feeding a fuel to at least one combustion chamber of the internal combustion engine, the fuel supply system including a storage tank, a pre-filter, a low pressure pump, a high pressure pump, a primary filter, a first pressure measuring device, and a second pressure measuring device, the storage tank being fluidically connected via the pre-filter to the low pressure pump, the low pressure pump being fluidically connected to the high pressure pump via the primary filter, the first pressure measuring device being configured to detect a first pressure value in the fuel supply system in a region of the fuel supply system associated with the pre-filter and upstream of the low pressure pump, the second pressure measuring device being configured to detect a second pressure value in the fuel supply system downstream of the low pressure pump in a region of the fuel supply system associated with the primary filter; and

a control unit which is operatively connected with the first pressure measuring device and with the second pressure measuring device and is equipped to monitor the first pressure value and the second pressure value for an error state of the fuel supply system and to detect the error state only if the error state is plausible based on the first pressure value and on the second pressure value.

13. The internal combustion engine of claim 12 , wherein the control unit is configured for carrying out a method for monitoring the fuel supply system in the internal combustion engine, the method including the steps of:

recording the first pressure value in the fuel supply system in the region of the fuel supply system associated with the pre-filter and upstream of the low pressure pump;

recording the second pressure value in the fuel supply system downstream of the low pressure pump in the region of the fuel supply system associated with the primary filter;

monitoring the first pressure value and the second pressure value for the error state of the fuel supply system; and

recognizing the error state only if the error state is plausible on a basis of both the first pressure value and the second pressure value.