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A correlation study of vehicle exhaust emissions measurements was conducted by the West Virginia University (WVU) Transportable Heavy-Duty Vehicle Emissions Testing Laboratory and the Los Angeles County Metropolitan Transportation Authority (MTA) Emissions Testing Facility. A diesel fueled transit bus was tested by both chassis dynamometer emissions testing laboratories. Exhaust emissions were sampled from the tested vehicle during the operation of the Federal Transit Administration (FTA) Central Business District (CBD) testing cycle. Data of gaseous and particulate matter emissions was obtained at each testing laboratory. The emissions results were compared to evaluate the effects of different equipment, test procedures, and drivers on the measurements of exhaust emissions of heavy-duty vehicles operated on a chassis dynamometer.

Regulated gaseous and particulate emissions were obtained from in-use vehicles, two trucks and two buses, operated on the Transportable Heavy Duty Engine Emissions Testing Laboratory. Presented here is the data on transient emissions from a refuse truck with a Cummins LTA10-260 engine, a GMC tractor with a CAT 3176 engine and two buses with Detroit Diesel 6V-92TA engines (one with a particulate trap and the other without) when tested on different fuels. The reported study on in-use heavy duty vehicles is part of an on-going program aimed at establishing a database on the exhaust emissions from vehicles tested on a chassis dynamometer under conditions that represent the ‘real-world’ situations. The paper also discusses, briefly, the entire testing laboratory. The Transportable Laboratory can be effectively used in testing programs, such as recall, deterioration and emission factors.

Growing concern about energy conservation and exhaust gas emissions from heavy duty engines of trucks and buses has increased the demand for the use of alternate fuels. A unique transportable testing laboratory designed to measure specific constituents of exhaust gas emissions from the engines of heavy duty vehicles operating on conventional or alternate fuels has been constructed by a team from West Virginia University. In this transportable facility, a special flat-bed trailer has been constructed to accommodate drive train units, free-rotating rollers, power-absorbing units to simulate road load, and flywheels to simulate vehicle inertia. Four hydraulic jacks are used to lower it to the ground at the fleet site. This allows the tested vehicle to be driven onto rollers embedded in the flat-bed. Hub adapters are connected at the outboard wheel locations at each side of the drive shaft of the vehicle.