Method for Recognizing a Defective Air Flow Sensor of an Internal Combustion Engine

摘要

A method and test device for recognizing detecting whether a mass air flow meter of intake air of an internal combustion engine is defective is provided. In the method and device, a test procedure is executed using a pilot controller while a mixture controller that is used in non-test engine operation is deactivated. The pilot controller for the mixture of fuel and air in the respective cylinders outputs control values which, during normal operation of the internal combustion engine via the mixture control, are varied on the basis of a mixture deviation of the current mixture from a stoichiometric mixture. The engine is set to one or more different idling speeds and at each respective idling speed the mixture deviation is detected. If the detected mixture deviation(s) (i'lA.) satisfy a predetermined criteria thresholds, the air flow meter is identified as defective.

主权项

1. A method for detecting whether an air mass flow meter of an internal combustion engine is defective, comprising the acts of:
outputting, from a pilot controller configured to control operation of a fuel injection system of the engine in a testing mode, actuating values used to control an amount of fuel injected by the fuel injection system to obtain a target mixture of fuel and air in respective cylinders of the engine, wherein the outputting of actuating values by the pilot controller occurs while a mixture controller configured to control operation of the fuel injection system during a non-testing mode in which the mixture is controlled on the basis of a mixture deviation from a target mixture measured by an exhaust gas lambda sensor is deactivated; setting using the pilot controller of an idling speed of the engine to at least one idling speed; detecting the mixture deviation from the stoichiometric mixture at each of the at least one idling speeds; and identifying the air mass flow meter as defective if the detected mixture deviation at the at least one idling speed satisfies at least one predetermined criterion.