A transportation refrigeration unit includes an evaporator circulating a flow of refrigerant therethrough to cool a flow of supply air flowing over the evaporator, a compressor in fluid communication with the evaporator to compress the flow of refrigerant, and an engine operably connected to the compressor to drive operation of the compressor. The engine includes an exhaust pathway to direct an exhaust gas flow from the transportation refrigeration unit, and a nozzle extending circumferentially around the exhaust pathway defining a nozzle flowpath between the exhaust pathway and the nozzle, the nozzle configured to flow a cooling airflow along the nozzle flowpath to reduce a temperature of the exhaust gas flow.