Engine control system

A method of controlling an engine which comprises an EGR device connecting an exhaust passage and an intake passage and provided with an EGR valve, and an engine control unit including an engine operation data calculator accumulating mileage of a vehicle or an engine operation period, a fuel injection controller controlling a fuel injection amount and a fuel injection timing, a controller controlling an opening of the EGR valve, a throttle valve controller controlling an opening of the intake throttle valve, the method comprising:

• calculating a mileage of a vehicle or an operation time of the engine;
• determining whether or not a total mileage or a total operation period of the engine is equal to or larger than a predetermined threshold;
• and
• delaying the fuel injection timing, increasing the opening of the EGR valve, and reducing the opening of the intake throttle valve.

An engine control system comprising:

• an EGR device connecting an exhaust passage and an intake passage, and including an 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 controller controlling an opening of the EGR valve,
• 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 an opening of the EGR valve, 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.