Investigation on the ultra low emissions of direct injection diesel engine operating on DMM-diesel blends

Influence of dimethoxymethane (DMM) addition, exhaust gas recirculation (EGR) and emission aftertreatment system on combustion and emissions of direct-injection (DI) diesel engine was investigated experimentally, and the approaches to meet Euro-III standard were discussed. Results show that, when using diesel fuel blended with 50% DMM volume fraction and EGR rate of 28% at low and middle load range and 7% at high load range, both NO_x and soot emissions of the engine reduce markedly; HC and CO emissions can be reduced by the use of diesel oxidation catalyst (DOC). In comparison to pure diesel fuel, application of DMM/diesel blends increases both premixed and diffusion combustion, leading to higher peak cylinder pressure and heat release rate. The combustion duration has not been lengthened evidently by using EGR. It is deducted that the natural aspirated diesel engine operating on high DMM addition rate, combined with EGR and DOC should be able to meet Euro-III emission standard of vehicle diesel engine.