MASS AIRFLOW SENSOR CALIBRATION EVALUATION

摘要

An engine has a controller for causing an EGR system to disallow EGR while concurrently executing a strategy for evaluating calibration of a mass airflow sensor in an intake system by operating the engine at each of different combinations of engine speed and engine load, and for each combination of engine speed and engine load, recording a corresponding output signal of the sensor and also calculating mass flow passing through an intake manifold as a function of intake manifold pressure, intake manifold temperature, speed of the engine, and volumetric efficiency of the engine. The output signal of the MAF sensor and the calculated mass flow passing through the intake manifold at least one combination of engine speed and engine load are used to evaluate the calibration the MAF sensor.

主权项

1. A method of evaluating calibration of a mass airflow (MAF) sensor providing an output signal measuring mass flow of air which has entered and is passing through a first portion of an intake system of an internal combustion engine which first portion is upstream of a mixing point at which any exhaust which has been created by combustion of fuel in cylinders of the engine and is allowed to pass through an exhaust gas recirculation (EGR) system entrains with air which has passed through the first portion of the intake system to create a mixture which then passes through a second portion of the intake system to the cylinders, the method comprising:
causing the EGR system to disallow passage of any exhaust to the mixing point; operating the engine at each of different combinations of engine speed and engine load; for each combination of engine speed and engine load, recording a corresponding output signal of the MAF sensor and also calculating mass flow passing through the second portion of the intake system as a function of pressure in the second portion of the intake system, temperature in the second portion of the intake system, speed of the engine, and volumetric efficiency of the engine; and using the output signal of the MAF sensor and the calculated mass flow passing through the second portion of the intake system at at least one combination of engine speed and engine load to evaluate the calibration the MAF sensor.