Patent ID: 6859719

Claim:
A control system for controlling a heater that heats an oxygen concentration detector provided in an exhaust passage of an internal combustion engine, when the engine is started, the control system comprising: detection means for detecting a start and a stop of the engine; and control means for controlling the heater by delivering a control signal to the heater, and wherein said control means comprises: first setting means for setting a value of the control signal to a first predetermined value until a first predetermined time period has elapsed after the start of the engine was detected by said detection means, second setting means for setting the value of the control signal to a second predetermined value smaller than the first predetermined value until a second predetermined time period has elapsed after the lapse of the first predetermined value, and third setting means for setting the value of the control signal to a third predetermined value smaller than the second predetermined value after the lapse of the second predetermined time period.