Patent ID: 6761023
Filing Date: 2004-07-13
Classification: F01N,F02D,Y02T

Abstract:
A method for diagnosing a catalytic converter of an internal combustion engine of a motor vehicle, comprising the steps of:injecting a fuel directly into a combustion chamber; burning the fuel during an intake phase in a first mode of operation and during a compression phase in a second mode of operation; sending an exhaust gas formed by combustion to the catalytic converter; injecting an additional amount of the fuel following combustion in the second mode of operation; measuring a temperature of the exhaust gas at least one of in and downstream from the catalytic converter; and comparing the temperature of the exhaust gas with a threshold value; wherein a first temperature increase is measured and compared with a second temperature increase measured with one of a new catalytic converter and a defective catalytic converter, and a difference between the first temperature increase and the second temperature increase is compared with at least one of an upper limit value and a lower limit value.