Method for detecting a leak in a crankcase breather

A method for detecting a leak in a crankcase breather of an internal combustion engine, in which crankcase breather a cavity of a crankcase, in an induction mode, passes purified blow-by gases, from which oil particles have been precipitated out, through a cylinder head of the internal combustion engine to a fresh air section of the internal combustion engine and, in a supercharged operating mode, passes the purified blow-by gases through a turbocharger or compressor to the fresh air section of the internal combustion engine, and a pressure sensor is provided for measuring a pressure in the cavity or the crankcase breather or in the cylinder head of the internal combustion engine, wherein an electronic control unit is provided for evaluating the signals of said pressure sensor, the method comprising the acts of:

• opening a volume-regulating valve of the crankcase breather in the induction mode to pass the purified blow-by gases through the cylinder head when an underpressure is present in an intake system of the internal combustion engine,
• closing the volume-regulating valve when an actual gas pressure in the intake system rises in the supercharged operating mode to feed the purified blow-by gases into the intake system via the turbocharger or compressor,
• measuring the actual gas pressure with the pressure sensor in the crankcase breather at a defined rotational speed and load of the internal combustion engine,
• reading a setpoint pressure value out from the electronic control unit and comparing an actual pressure value, obtained by measuring the actual gas pressure, with the setpoint pressure value, and
• detecting a leak with the electronic control unit when the electronic control unit determines that the setpoint pressure value is exceeded by the actual gas pressure value.