Testing the light-off behavior of a catalyst in an internal combustion engine comprises comparing the temperatures of a test catalyst and a new catalyst

摘要

Testing the light-off behavior of a catalyst in an internal combustion engine comprises measuring the temperature of a new catalyst under hot running conditions over a predetermined time, storing the measured temperature, similarly measuring the temperature of the test catalyst, and comparing the two temperatures. An independent claim is also included for testing the light-off behavior of a catalyst in an internal combustion engine by determining reference values of a first diagnostic parameter for differently aged catalysts by comparing the conversion rates of the catalysts with those of a new catalyst under hot running conditions; similarly determining reference values of a second diagnostic parameter that correlates with the first parameter; storing the reference values; determining a value of the second diagnostic parameter for the test catalyst by comparing the conversion rates of the test catalyst with those of a new catalyst under hot running conditions; and calculating the value of the first diagnostic parameter for the test catalyst from the value of the second diagnostic parameter using the stored reference values.