Throttling effects on dual-fuel premixed charge compression ignition under low load condition in a heavy duty diesel engine

Abstract

For the last five decades, many engine combustion researchers have been researching about advanced combustion technologies such as homogeneous charge compression ignition (HCCI) and dual-fuel premixed charge compression ignition (Dual-Fuel PCCI) for reducing particulate matter (PM) and nitrogen oxides (NOx) emissions simultaneously in diesel engines. However, the advanced combustion technologies have drawbacks such as high amount of unburned hydrocarbon (UHC) and carbon monoxide (CO) emissions due to the incomplete combustion at all operating ranges especially under the low load conditions. In this study, throttling was adopted to reduce the UHC and CO emissions. Controlling the throttle could improve the exhaust emission and the combustion stability performance by increasing the global equivalence ratio under low load conditions. The results suggest that controlling the charge air quantity is an effective way to improve combustion efficiency (ηc), and to extend low load operating ranges of the DF-PCCI combustion.