Patent ID: 8069650

Claim:
A method for reducing heat loss in an exhaust aftertreatment system connected to the exhaust pipe of an internal combustion engine, which engine is used to propel a vehicle and is equipped with a valve-controlled EGR duct for adjustable recirculation of exhaust gases from the exhaust side of the engine to its induction side, comprising detecting that both a braking system and a throttle control mechanism of the vehicle are not activated and that the vehicle is being driven at a speed in excess of a predetermined value, and upon detecting that the braking system and the throttle control mechanism are not activated and that the vehicle is being driven at the speed in excess of the predetermined value, regulating gas flow through the EGR duct so that gas flow to an exhaust aftertreatment system is reduced to a level which is less than about 50% of the gas flow of the exhaust after-treatment system with a shut-off EGR valve.