Verification of a level-3 diesel emissions control strategy for transport refrigeration units.

摘要

Transport Refrigeration Units (TRUs) are refrigeration systems used to control the environment of temperature sensitive products while they are being transported from one place to another in trucks, trailers or shipping containers. The TRUs typically use an internal combustion engine to power the compressor of the refrigeration unit. In the United States TRUs are most commonly powered by diesel engines which vary from 9 to 40 horsepower. TRUs are capable of both heating and cooling. The TRU engines are relatively small, inexpensive and do not use emissions reduction techniques such as exhaust gas recirculation (EGR). A significant number of these engines operate in highly populated areas like distribution centers, truck stops, and other facilities which make them one of the potential causes for health risks to the people who live and work nearby.;Diesel particulate matter (PM) is known for its adverse effects on both human beings and the environment. Considering these effects, regulatory bodies have imposed limitations on the PM emissions from a TRU engine. The objective of this study was to measure and analyze the regulated emissions from a TRU engine under both engine out and particulate filter system out conditions during pre-durability (when the filter system was new) and post-durability test (after the filter system was subjected to 1000 hours in-field trial). The verification program was performed by the Center for Alternative Fuel, Engines and Emissions (CAFEE) at West Virginia University (WVU). In this program, a catalyzed silicon carbide (SiC) diesel particulate filter (DPF) was evaluated and verified as a Level-3 Verified Diesel Emissions Control Strategy (VDECS) (.85% PM reduction) under California Air Resources Board (CARB) regulations 2702 [1].;The emissions result showed that the filter system reduced diesel PM by a percentage of 96 +/- 1 over ISO 8178-C1 [2] cycle and 92 +/- 5 over EPA TRU [3] cycle, qualifying as a Level 3 VDECS. The percentage emission reduction in hydrocarbons (HC) and carbon monoxide (CO) was 76.8 +/- 4.8 and 72.2 +/- 5.2, respectively over both ISO 8178-C1 [2] and EPA TRU [3] cycles. It was also observed that there was 3.6 +/- 2.9 and 7.2 +/- 3.1 percentage reduction in oxides of nitrogen (NOx) and nitric oxide (NO), respectively with a slight increase in fuel consumption and carbon dioxide as a consequence of increased exhaust back pressure.;It is required by the CARB regulations that the diesel emissions control strategy must not increase emissions of NO2 by more than 20% by mass over the baseline value. In this study, it was observed that the total increase in NO2 level was 5.6 +/- 2.6 percent, well within the limit specified by the CARB.