Transportation refrigeration units (TRUs) are used to preserve perishable products in different types of mobile sources such as semi-trailer van, truck vans, shipping containers, and rail cars. TRUs are directly or indirectly powered by diesel engines ranging in sizes from 7 to 36 horsepower (hp), with 35 hp being the most common size. The California Air Resources Board (CARB) estimates that about 40,200 TRUs operating in California at any given time with an annual diesel consumption of approximately 20 million gallons. CARB also estimates PM and nitrogen oxides (NOx) emissions from these units are 2 and 20 tons per day (tpd), respectively. PM emissions are projected to increase to about 2.5 tpd in 2010 and to over 3 tpd by 2020.

Gas-to-liquid fuels (GTL) may be an option to reduce the PM from TRUs. Previous work has shown PM reductions from a wide range of light- and heavy-duty diesel engines operating on GTL fuels. A second option is to combine emission controls with alternative fuels for additional emission reductions. The combination of alternative fuels and emission control systems has been used successfully in on-road applications. Similar applications exist in off-road applications. The proposed project is to asses the impact of GTL fuel and advanced emissions control systems on TRU’s operating in the South Coast Air Basin