Patent ID: 6148808
Filing Date: 2000-11-21
Classification: F02D

Abstract:
A control method for fueling a plurality of individual cylinders of a multi-cylinder internal combustion engine based on an output signal of an oxygen sensor positioned to respond to a combination of exhaust gases generated in the individual cylinders, the control method comprising the steps of:sampling the oxygen sensor output signal in synchronism with firing events in each of the individual cylinders;computing a measure of air/fuel maldistribution among the engine cylinders based on the samples of the oxygen sensor output signal; retrieving a previously stored offset value that associates the sampled output signals with the individual cylinders;fueling the individual cylinders based on the retrieved offset value and the sampled output signals;updating the measure of air/fuel maldistribution; andif the updated measure of air/fuel maldistribution fails to decrease in response to the fueling based on the retrieved offset value, determining a new offset value and storing the new offset value in place of the retrieved offset value.