There is limited field data that can be used for fuel use and emissions analyses of nonroad diesel construction equipment. This paper summarizes the results of field research that used a portable emission monitoring system (PEMS) to collect fuel use and emissions data from eight backhoes, six bulldozers, three excavators, four generators, six motor graders, three off-road trucks, one skid-steer loader, three track loaders, and five wheel loaders while they performed various duty cycles. These tests produced approximately 119 hours of field data for petroleum diesel and approximately48 hours for B20 biodiesel. Engine attribute data including horsepower, displacement, model year, engine tier, and engine load were measured to determine their influence on fuel use rates and emission rates of NOx, HC, CO, CO2, and opacity. Mass per time fuel use rates were developed for eachitem of equipment as well as mass per time and mass per fuel used emission rates for each pollutant. For petroleum diesel, fuel use and emission rates of each pollutant were found to increase with engine displacement, horsepower, and load, and to decrease with model year and engine tier. The results were qualitatively similar for B20. Fuel-based emission rates were found to have less variability and less sensitivity to engine size and load than time-based emission rates. Hence, where possible, development ofemission inventories based on fuel consumed, rather than time of activity, is preferred.
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