Method and device for operating an internal combustion engine

A device for operating an internal combustion engine having multiple cylinders, fuel being injectable into the multiple cylinders via corresponding injectors, corresponding intake valves allowing entry of air in order to form an air-fuel mixture in the cylinders for providing a drive torque, and combustion exhaust gas being dischargeable from the cylinders via a catalytic converter, the device comprising:

• a control unit configured to:
• operate the internal combustion engine in a first engine operating mode in which no fuel is injected into at least one first cylinder, so that the at least one first cylinder does not contribute to the drive torque, and fuel is only injected into at least one second cylinder in order to provide the drive torque;
• switch to a second engine operating mode in which fuel is injected into all cylinders, so that each of the cylinders contributes to providing the drive torque;
• cause the combustion using excess air in the at least one second cylinder in switching to the second engine operating mode, so that a portion of the air let into the at least one second cylinder together with the combustion exhaust gas passes into the catalytic converter;
• and
• determine a quantity of fuel which has penetrated into the at least one first cylinder as a result of leakage from corresponding injectors into combustion chambers of the at least one first cylinder during the first engine operating mode, the quantity being determined as a function of at least one of the rotational speed and a pressure in the fuel delivery system for at least one injector.

An engine system comprising:

• an internal combustion engine having multiple cylinders, wherein each of the cylinders includes an injector for injecting fuel into the multiple cylinders of the internal combustion engine, and intake valves for letting air into the cylinders in order to form an air-fuel mixture in the cylinders for providing a drive torque, a catalytic converter being provided through which combustion exhaust gas from the cylinders is discharged;
• and
• a control unit configured to:
• operate the internal combustion engine in a first engine operating mode in which no fuel is injected into at least one first cylinder, so that the at least one first cylinder does not contribute to the drive torque, and fuel is only injected into at least one second cylinder in order to provide the drive torque;
• switch to a second engine operating mode in which fuel is injected into all cylinders, so that each of the cylinders contributes to providing the drive torque;
• cause the combustion using excess air in the at least one second cylinder in switching to the second engine operating mode, so that a portion of the air let into the at least one second cylinder together with the combustion exhaust gas passes into the catalytic converter;
• and
• determine a quantity of fuel which has penetrated into the at least one first cylinder as a result of leakage from corresponding injectors into combustion chambers of the at least one first cylinder during the first engine operating mode, the quantity being determined as a function of at least one of a rotational speed and a pressure in the fuel delivery system for at least one injector.