Patent ID: 7406959

Claim:
An engine control system comprising: a first EGR passage connecting an engine exhaust passage and an intake passage and provided with an EGR cooler and a first EGR valve; a second EGR passage placed in parallel to the first EGR passage and provided with a second EGR valve; an intake throttle valve placed in the intake passage; and an engine control unit which includes an engine operation data calculator accumulating mileages of a vehicle or an engine operation period, a fuel injection controller controlling a fuel injection amount and a fuel injection timing, an EGR valve controller controlling openings of the first and second EGR valves, a throttle valve controller controlling an opening of the intake throttle valve, and an EGR passage cleaning controller which delays the fuel injection timing, increases openings of the first and second EGR valves, and reduces an opening of the intake throttle valve when the total mileage or the total operation period calculated by the engine operation data calculator becomes equal to a predetermined threshold.