Patent ID: 7921828

Claim:
Method to reduce combustion by-product deposit build-up within a heat exchanger of a motor vehicle, wherein said heat exchanger processes a gas flow including exhaust gas, by maintaining a minimum exhaust gas recirculation flow velocity within the heat exchanger, the method comprising: determining the minimum exhaust gas recirculation flow velocity selected based on avoiding excessive fouling rates; reducing a heat exchanger total gas flow cross section to locally increase an exhaust gas recirculation flow velocity, the locally increased exhaust gas recirculation flow velocity maintains the minimum exhaust gas recirculation flow velocity by offsetting decreases in exhaust gas recirculation flow velocity resulting from cooling of the exhaust gas recirculation flow through the length of the heat exchanger; and wherein the exhaust gas recirculation flow comprises a diverted portion of an exhaust gas flow utilized for controlling combustion within a combustion chamber.