A comparison of steady state and transient emissions from a heavy-duty diesel engine [electronic resource] /

by Bane, Bradley R.

The objective of this thesis was to research two aspects of heavy-duty diesel engine emissions. The first was to examine the effects of engine oscillations on engine emissions. The second objective was to examine a steady state based emission model and compare the results with measured transient emissions. A Detroit Diesel Corporation (DDC) Series 60 engine was operated on a DC dynamometer with the engine speed held constant and the torque input in a trapezoidal wave configuration to examine the effects on engine emissions with different frequencies of trapezoidal variations in engine load. Emissions were also measured during the operation of the heavy-duty diesel engine over a 101-point steady state grid dispersed evenly across the engine map, consisting of speed and torque, of the DDC Series 60 engine. Models were formulated as a function of engine power for each emission species. The DDC Series 60 was operated throughout five different transient cycles and emissions were measured. Emissions were also equated from the steady state models based on the engine power measured during the transient cycles and compared to the measured transient emissions. Sensitivity analysis was performed to determine the sensitivity of the steady state model. CO2 emissions remained relatively unchanged with increased transient behavior and were represented well from the steady state based model. NOX decreased slightly with an increased frequency of the trapezoidal variation and was not represented as well as CO2 by the steady state emission model. CO and PM emissions were transient based and decreased with an increased frequency of the trapezoidal variation. CO and PM did however represent emissions well by the steady state model on an integrated brake specific basis. HC resulted from increased frequencies from the trapezoidal variations in a reduction and was not modeled well by the steady state emission HC model. Emissions prediction based on engine power was improved by steady state emissions data when the operating points for the model of engine speed and torque more closely resembled the operating points of the transient cycle.