Estimating fuel use and emission rates of nonroad diesel construction equipment performing representative duty cycles

This dissertation presents a methodology for estimating weighted-average fuel use rates and emission rates NOx, HC, CO, and PM of construction equipment performing representative duty cycles based on field data collected from 34 items of construction equipment. An engine modal analysis determined the variation of fuel use and emission rates with respect to 10 individual engine modes representing increasing engine loads. Multiple linear regression models estimated the fuel use rate of engine modes 2--10; an average fuel use rate was used to estimate the idling fuel use rate. Efforts to develop linear regression models for modal emission rates proved ineffective due to low R2 values and unacceptable p-values for variable coefficients, thus, average modal emission rates of each pollutant based on the field data were used. The modal fuel use rates were weighted by the fraction of time spent in each engine mode to estimate a weighted-average mass per time fuel use rate for the representative duty cycle. The modal emission rates for each pollutant were weighted by the fraction of fuel used in each engine mode to estimate a weighted-average mass per fuel used emission rate for the representative duty cycle. The weighted-average emission rate for each pollutant was multiplied by the weighted-average fuel use rate to determine the mass per time emission rate for the duty cycle. Based on response plots of the actual versus estimated values, the methodology reliably estimated fuel use rates and emission rates of NOx, CO, and PM.