NOVELTY - The exhaust system (5) for an internal combustion engine with a circulating coolant for driving an automotive vehicle, comprises: an engine with an exhaust manifold, from which a exhaust stream of combustion gas is expelled by engine operation, where the exhaust gas has temperatures varying over a temperature range; and an exhaust gas conduit system for conducting the gas in a contained flow path from the exhaust manifold to a gasflow terminus, at which the exhaust gas is discharged from the vehicle, where the contained flow path has a location with a perimeter.    USE - The exhaust system is useful for an internal combustion engine with a circulating coolant for driving an automotive vehicle.    ADVANTAGE - The exhaust system efficiently extracts a portion of the thermal energy in the internal combustion engine and converts the extracted energy to electrical energy thus reducing fuel economy of the vehicles, and maintains a stable thermal environment in the combustion engine.    DETAILED DESCRIPTION - The exhaust system (5) for an internal combustion engine with a circulating coolant for driving an automotive vehicle, comprises: an engine with an exhaust manifold, from which a exhaust stream of combustion gas is expelled by engine operation, where the exhaust gas has temperatures varying over a temperature range; an exhaust gas conduit system for conducting the gas in a contained flow path from the exhaust manifold to a gasflow terminus, at which the exhaust gas is discharged from the vehicle, where the contained flow path has a location with a perimeter for transfer of heat from the exhaust gas to a thermoelectric device; a first body of thermally conductive material contained and interposed around a perimeter of the exhaust gas flow path and between the exhaust gas and a high temperature side of the thermoelectric device; a contained, second body of thermally conductive material; a bypass pipe located in parallel with the thermoelectric device; a valve for directing the engine exhaust through the thermoelectric device or through the bypass pipe; a temperature sensor; a controller; a valve actuator with a sensor; and an air inlet upstream of the thermoelectric device. The thermoelectric device: comprises a thermoelectric module for generating electrical energy from thermal energy of the exhaust; has the high temperature side and a low temperature side; and is shaped and placed around the perimeter of a portion of the exhaust gas flow path with the high temperature side in heat transfer contact with the flowing exhaust gas stream. The first contained thermally conductive material provides the heat transfer path between the exhaust gas and the high temperature side of the thermoelectric device. The body of the thermally conductive material has a mass and a melting point or melting range such that heat transferred from the exhaust gas melts a portion of the body of material. The latent heat of the partially melted body of the material reduces the temperature at the high temperature side of the thermoelectric device as it is heated by the exhaust gas. The second body of thermally conductive material: is present in heat transfer contact with the low temperature side; has a mass and a melting point or melting range such that heat transferred from the exhaust gas and through the thermoelectric device melts a portion of the second body of material, where the latent heat of the partially melted second body of material reduces the temperature at the low temperature side of the thermoelectric device as it is heated by the exhaust gas; and is present in thermal contact with the circulating engine coolant. The air inlet passage has an opening, which is controlled by a valve for admitting ambient air to cool the exhaust. The thermoelectric module comprises n-type and p-type semiconductor elements consisting of filled or partially filled skutterudites and filler atoms. An INDEPENDENT CLAIM is included for a thermoelectric device.    DESCRIPTION OF DRAWING(S) - The figure shows a schematic sectional view of a vehicle engine, exhaust system and thermoelectric device.    Automobile (1)    Exhaust system (5)    Resonator (7)    Muffler (8)    Tailpipe. (9)