Potential of emission reduction of a turbo-charged non-road diesel engine without aftertreatment under multiple operating scenarios

Abstract

In this study, the bench test of a non-road diesel engine was conducted under universal conditions, non-road steady-state cycle (NRSC) and non-road transient cycle (NRTC). To reduce the raw emissions of the tested non-road diesel engine, some improvement measures, such as pre-injection, smoke limit, and intake throttle degree control strategy, were applied to the optimized engine. The experiment results showed that particulate matter (PM) emissions are reduced significantly at medium-high speed and low load. The maximum and average proportion of PM emissions reduction at 0–30% load and 1400–2200 r/min are 68.4% and 47.5%, respectively. However, the optimized nitrogen oxide (NOx) emissions are higher than that of the original engine, particularly under low load working conditions. Nevertheless, at medium-high speed and load, NOx emissions of the optimized engine were reduced. PM and NOx emissions decreased by 12.3% and 2.4%, respectively, under NRSC. Under NRTC, PM and NOx emissions decreased by 5.2% and 5.5%, respectively. Unburned hydrocarbon (HC) and carbon monoxide (CO) were always maintained at extremely low emission levels. Furthermore, the fuel consumption almost remained constant under all operating conditions. Thus, this study demonstrates the emission reduction potential in non-road diesel engines without considerable payment.