Method and system for controlling the temperature of an exhaust system having a variable length exhaust pipe

A system for controlling the temperature of an exhaust system of an internal combustion engine, the exhaust system having a variable length exhaust pipe including a short path and a long path, the exhaust system further having an exhaust valve positioned in the exhaust pipe for regulating the flow of exhaust gas between the short path and the long path, the system comprising:

• control logic operative to estimate a plurality of exhaust temperatures at various locations on the exhaust system, determine a plurality of maximum temperatures, compare the plurality of estimated exhaust temperatures with the plurality of maximum temperatures, and to control the exhaust valve so that the exhaust gas flows through the long path of the exhaust pipe if a preselected number of the plurality of estimated exhaust temperatures exceed the plurality of maximum temperatures so as to aid in cooling the exhaust gas.

An article of manufacture for an exhaust system of an internal combustion engine, the exhaust system having a variable length exhaust pipe including a short path and a long path, the exhaust system further having an exhaust valve positioned in the exhaust pipe for regulating the flow of exhaust gas between the short path and the long path, the article of manufacture comprising:

• a computer storage medium having a computer program encoded therein for estimating a plurality of exhaust temperatures at various locations on the exhaust system, determining a plurality of maximum temperatures, comparing the plurality of estimated exhaust temperatures with the plurality of maximum temperatures, and controlling the exhaust valve so that the exhaust gas flows through the long path of the exhaust pipe if a preselected number of the plurality of exhaust temperatures exceed the plurality of maximum temperatures so as to aid in cooling the exhaust gas.