US Patent 7210289 Output control system for engine with exhaust control function

An engine output control system includes an engine ECU having a fundamental ignition timing map, a fundamental fuel injection quantity map, a target throttle angle determination unit for determining a target throttle angle of an exhaust control valve, an exhaust control valve diagnosis unit for diagnosing operation of the exhaust control valve, an ignition timing map to be used during an abnormality for determining fundamental ignition timing when the exhaust control valve operates abnormally, and an abnormal fuel injection thinning-out table for determining a reduced rate of fuel injection when the exhaust control valve has been diagnosed as abnormal. The exhaust control valve driving unit supplies a driving current to an actuator in such a manner that the target throttle angle notified by the engine ECU coincides with actual valve throttle angle. The system is capable of obtaining sufficient traveling performance even when an exhaust control valve has is operating abnormally.