Method and device for inspecting the functionality of a crankcase ventilation system of an internal combustion engine

A device for checking functionality of a crankcase ventilation system of an internal combustion engine, the crankcase ventilation system comprising:

• a crankcase having a crankcase outlet,
• two crankcase ventilation lines arranged between the crankcase outlet and an associated introduction point into an air path of the internal combustion engine, the crankcase outlet in fluid communication with the two crankcase ventilation lines of the crankcase ventilation system, the two crankcase ventilation lines introduce gas from the crankcase into the air path, and
• a pressure control valve in fluid communication with the two crankcase ventilation lines in a location downstream from the crankcase outlet and upstream from each associated introduction point,
• a control unit configured to:
• measure a pressure in the crankcase by a crankcase pressure sensor positioned in the crankcase,
• supply the measured pressure values to a control unit,
• detect a change in an operating point of the internal combustion engine, wherein the change of the operating point includes a negative load change or a positive load change,
• calculate a gradient with respect to time of the measured crankcase pressure,
• perform a gradient check of the calculated gradient,
• check whether the gradient satisfies a specified criterion to determine whether a leak is present in the two crankcase ventilation lines, wherein the specified criterion depends on whether a positive or a negative load change was detected,
• return to the measurement of the crankcase pressure when the gradient satisfies the specified criterion,
• recording an entry in a fault memory when the gradient does not satisfy the specified criterion, and
• if the presence of a leak is determined, determining which of the two crankcase ventilation lines is defective by evaluating the gradient during the detected positive or negative load change.