Internal-combustion engine e.g. petrol engine, diagnosing method for motor vehicle, involves recognizing error, when reference value that is difference between actual values of operating characteristic is smaller than predetermined value

摘要

The method involves determining actual value of an operating characteristic of an internal-combustion engine (1000) during operation of a gas shuttle valve e.g. intake valve (1030), in accordance with a strategy. The gas shuttle valve is opened and closed by a valve adjusting device (1300) during operation of the engine in accordance with another strategy in an operating condition of the engine. A reference value is determined depending on the difference between the former and the latter actual values, and an error is recognized, when the reference value is smaller than a predetermined value. Independent claims are also included for the following: (1) a controller for diagnosing of an internal-combustion engine (2) a computer program having a set of instructions for performing a method for diagnosing an internal-combustion engine (3) a computer program product having a set of instructions for performing a method for diagnosing an internal-combustion engine.