Quantifying effects of vehicle weight and terrain on emissions, fuel economy, and engine behavior [electronic resource] /

by Strimer, Corey M.

On-board emissions measurement for heavy-duty vehicles has garnered greater significance because 2007 marks the beginning of gaseous emissions monitoring for in-use vehicles in the United States [1]. Emissions compliance must be shown in a “not to exceed” (NTE) zone that emphasizes engine operation at higher power. An over-the-road 1996 Peterbilt tractor was instrumented with the West Virginia University Mobile Emissions Measurement System (MEMS) to determine how often the truck entered the NTE, and the emissions from the vehicle, as it was driven over varying terrain at multiple test weights. Distance-specific NOX emissions increase by approximately X/2% for an X% increase in test weight. Fuel economy declined by approximately 0.5 miles/gallon for every 15,000 lb. in added test weight. Almost a quarter of entrances into the NTE region were caused by changing gears. This result should be considered when comparing data from manual transmission vehicles to those with automatic transmissions.