Chassis Dynamometer Emissions Testing Results for Diesel and Alternative-Fueled Transit Buses

The Los Angeles County Metropolitan Transportation Authority (MTA) currently operates a state-of-the-art Heavy-Duty Vehicle Emissions Testing Facility (ETF) in cooperation with the California Air Resources Board (CARB), the California Energy Commission (CEC) and the South Coast Air Quality Management District (SCAQMD) for the purpose of evaluating the on-road exhaust emissions of heavy-duty trucks and buses. The ETF, consisting of a Schenck-Pegasus chassis dynamometer and a Horiba Instruments Vehicle Emissions Testing System (VETS), is capable of sampling and analyzing the exhaust emissions of both alternate fueled and diesel fueled transit buses and heavy-duty trucks. This paper will provide background on the design and operation of the ETF as well as emissions testing results for baseline diesel, particulate trap-equipped diesel, compressed natural gas, 100 percent methanol and methanol/Avocet fueled transit buses.