Patent ID: 8341951

Claim:
An apparatus for a vehicle with an engine comprising: an exhaust system through which exhaust gas is discharged from the engine; a heat exchanger positioned at least partially within the exhaust system; coolant flow passages in thermal communication with the engine and with the heat exchanger; a bypass valve operable to direct the exhaust gas across the heat exchanger along a first flow path to transfer exhaust heat to the coolant flow passages in a first coolant heating mode; operable to direct at least a portion of the exhaust gas across the heat exchanger along a second flow path to transfer exhaust heat to the coolant flow passages in a second coolant heating mode; wherein the second flow path is restricted relative to the first flow path; and operable to direct the exhaust gas to bypass the heat exchanger in a bypass mode during which no significant coolant heating occurs via the heat exchanger; wherein the bypass valve has a first portion and a second portion movable independently from one another; wherein the first portion is in a first position and the second portion is in a second position in the second coolant heating mode such that the second portion partially blocks flow to the heat exchanger to establish the second flow path; and a barrier extending from the heat exchanger and arranged so that the second portion of the bypass valve contacts the barrier in the second coolant heating mode to direct exhaust gas between the bypass valve and the heat exchanger such that exhaust gas flows over only a portion of the heat exchanger and is blocked from a remaining portion of the heat exchanger by the barrier and the second portion of the bypass valve.