Emissions, Performance, and Duty Cycle Measurements of Diesel Powered TRUs 2007-01-1087

In recent years emission control agencies have turned their attention to to the cleanup of diesel engines, both mobile and stationary. This paper is one of the first attempts to characterize the load and emissions of a subsection of stationary diesel emissions, specifically Truck/Trailer Refrigeration Units (TRUs). These devices are used to keep refrigerated or frozen cargo cold when it is being shipped/delivered. Two general sizes of TRUs were tested, smaller TRUs for cooling box trucks, used for local deliveries, and large TRUs, used for long hauling and very large deliveries. After observing a matrix of these units over a large spectrum of temperatures it was found that, although there were multiple control strategies, they all heavily relied on pulling the trailer down to the set point temperature as fast as the engine and refrigeration unit would allow.

Emissions tests were taken in the field at the General Produce Warehouse in Sacramento over a large range of temperatures using this control strategy. It was found that after testing the amount of O₂, CO, CO₂, and NO_x in the exhaust system, the major pollution present in large amounts was NO_x (PM was not measured.). Engine power was found by doing a carbon balance with CO₂ and comparing the results with a well documented diesel engine. Using the NO_x measurements in grams of pollution per hour, as well as per unit energy output from the engine, then the cooling from the trailer was found as a function of energy used.