Patent ID: 6131447
Filing Date: 2000-10-17
Classification: F01N,F02D,Y02A,Y02T

Abstract:
A process for checking the operability of a secondary air pump in a motor vehicle having an internal-combustion engine and an electronic control unit, the process comprising the acts of:detecting a rotational speed of the internal-combustion engine and a throttle valve angle in an intake system of the internal-combustion engine;estimating a rate of air flow into cylinders of the internal-combustion engine as a function of the detected rotational speed and throttle valve angle based on a characteristic diagram stored in the electronic control unit;sensing an overall rate of air flow via an air flow rate sensor, said overall rate of air flow being composed of the air flow into the cylinders of the internal-combustion engine and a secondary air flow delivered via a secondary control pipe into an exhaust gas duct; andanalyzing any difference between the overall rate of air flow and the rate of air flow into the cylinders of the internal-combustion engine.