Patent ID: 8521354
Filing Date: 2013-08-27
Classification: F02D,Y02T

Abstract:
1. A method of diagnosing failure in connection with a mass airflow sensor used in an airflow-based engine control system for an internal combustion engine, the engine having one or more cylinders and an exhaust gas recirculation (EGR) system that recirculates exhaust at a variable EGR rate, comprising: obtaining a measured airflow mass value from the mass airflow sensor; obtaining a measured intake oxygen concentration value; obtaining a measured exhaust oxygen concentration value; calculating an EGR rate based on the relationship between the intake oxygen concentration value and the exhaust oxygen concentration value; obtaining a measured intake manifold pressure value; obtaining a measured intake manifold temperature value; calculating a total gas flow rate into the cylinders, based on the measured intake pressure value and the measured intake manifold temperature value; subtracting the EGR rate from the total gas flow rate, thereby obtaining a calculated value for a mass air flow rate, which is not based on the measured airflow mass value; comparing the measured airflow mass value to the calculated airflow mass value; and generating airflow mass sensor failure data if the comparing step does not result in a match.