Patent ID: 6374818
Filing Date: 2002-04-23
Classification: F02D,Y02T

Abstract:
An apparatus for determining a failure of an oxygen concentration sensor of an internal combustion engine that includes an exhaust system, and a catalyst arranged in said exhaust system, and is capable of carrying out a fuel cut-off operation, said oxygen concentration sensor being arranged in said exhaust system at a location downstream of said catalyst, for generating a signal indicative of a sensed concentration of oxygen in exhaust gases,the apparatus comprising: oxygen concentration change-determining means for determining whether or not a signal value of said signal from said oxygen concentration sensor has crossed a predetermined threshold value after termination of said fuel cut-off operation; exhaust gas amount calculation means for calculating an integrated amount of said exhaust gases exhausted from said engine after said termination of said fuel cut-off operation; and failure determination means for determining that said oxygen concentration sensor has failed when said oxygen concentration change-determining means determines that said signal value has not crossed said predetermined threshold value, in the case of said integrated amount of said exhaust gases having reached a predetermined value.