A simulation and experiment study on the emission reduction potential of light-duty diesel engine retrofitted with an after-treatment system: a case study

Abstract

ABSTRACT In this study, a simulation and experiment on laboratory conditions were conducted to investigate the effects of a retrofitted DOC-DPF-SCR system on the performance and pollutants of an in-service old-generation light-duty diesel engine. Simulations demonstrate that DOC and SCR have little effect on engine performance, but the particle filter does. With 220 mm, 240 mm, and 260 mm DPF cores, brake power was reduced by 1.9%, 4.5%, and 12.0% at rate condition and 1.2%, 3.6%, and 10.8% at maximum brake torque condition. The after-treatment system can reduce soot by 64.8% to 81.9% at full load conditions and 55.6% to 83.3% as the load varies at a constant speed. NOx emissions were reduced significantly by an average value of 81.9% at full load and 21.7% to 78.1% at a constant speed, depending on load. The DOC combined with DPF also influenced incomplete combustion products as the concentration of CO and HC decreased by 73.6% and 76.5% on average at full load conditions. Following emission standards, HC and CO emissions were reduced by 63.8% and 68.7%, respectively; NOx and PM were decreased by 71.1% and 76.6% when the engine was retrofitted with the after-treatment system. After retrofitting, the old-generation diesel engine can pass the Euro II standard.