Effects of LPG on the combustion and emission characteristics of DME-diesel dual-fuel engines

In order to overcome the combustion knock caused by preignition of DME, the experimental investigation on the effects of liquefied petroleum gas (LPG) on the combustion and emission characteristics of DME-diesel PCCI was carried out. The experiments were conducted on a modified direct injection diesel engine with port injection of DME and LPG. Results showed that by increasing the proportion of LPG in the DME/LPG mixture, the igniting timing was delayed, the combustion duration was shortened, and the maximum cylinder temperature and pressure gradually decreased. The effective thermal efficiency of the engine declined slightly with an increase of LPG proportion in the DME/LPG mixture, but was still higher than that of DI diesel engine. Moreover, the NO_x emissions were reduced to a certain extend and the particulate emission stayed at the same level when blending LPG into DME. These results can provide a reference for designing more energy-efficient and environment-friendly internal combustion engines.