METHOD AND APPARATUS FOR DETERMINING SENSITIVITY OF HYDROCARBON SENSOR FOR INTERNAL COMBUSTION ENGINE

摘要

PROBLEM TO BE SOLVED: To reliably deterimine the sensitivity of a hydrogen carbon sensor by a method of technically as simple as possible irrespective of deterioration and irrespective of measurement of other engine operation data as much as possible. SOLUTION: A heatable sensor electrode 12 for detecting hydrocarbon molecules generates a voltage being reference for hydrocarbon concentration. Voltage depending on the sensor electrode 12 is short-circuited for a short time using a field effect transistor FET, and sensor sensitivity is determined from a time constant which is elapsed time of the voltage until it again reaches a predetermined voltage value after the short-circuiting.