NOVELTY - An exhaust silencer (1) has a thermo-acoustic cooling device (10) provided in an exhaust pipe (3). The cooling device comprises a thermo-acoustic generator (12A) producing waves on working gas in the loop piping (11) by thermo-acoustic self-excited oscillation, and a heat pump (12B) operated by the wave generation. Each of the generator and the heat pump includes a high temperature side heat exchanger (13A,15A) and a low temperature side heat exchanger (13B,15B).    USE - Exhaust silencer for exhaust system of vehicle.    ADVANTAGE - Sound pressure level of exhaust sound is lowered by cooling the exhaust gas instead of using a dynamic mechanism.    DETAILED DESCRIPTION - An exhaust silencer (1) has a thermo-acoustic cooling device (10) provided in an exhaust pipe (3). The cooling device comprises a thermo-acoustic generator (12A) producing waves on working gas in the loop piping (11) by thermo-acoustic self-excited oscillation, and a heat pump (12B) operated by the wave generation. Each of the generator and the heat pump includes a high temperature side heat exchanger (13A,15A) and a low temperature side heat exchanger (13B,15B). The high temperature side heat exchanger of the generator connects one part of the exhaust pipe, while the low temperature side heat exchanger of the heat pump connects another, downstream part of the exhaust pipe. The remaining high and low temperature side heat exchangers are cooled with air or engine cooling water to remove heat. The heat of the exhaust gas flowing through the pipe is supplied to the high temperature side heat exchanger of the generator. The exhaust gas is cooled with the low temperature side heat exchanger of the pump.    DESCRIPTION OF DRAWING(S) - The drawing shows the perspective view of an exhaust silencer. (Drawing includes non-English language text)    Exhaust silencer (1)    Exhaust pipe (3)    Thermo-acoustic cooling device (10)    Loop piping (11)    Thermo-acoustic generator (12A)    Heat pump (12B)    High temperature side heat exchanger (13A,15A)    Low temperature side heat exchanger (13B,15B)