Improvement of emission characteristics and thermal efficiency in diesel engines by fueling gasoline/diesel/PODEn blends

Abstract

PODEn (polyoxymethylene dimethyl ethers) stand for the mixtures of ethers with the chemical formula CH3O(CH2O)nCH3, which have high cetane number and nearly 50% oxygen content. Gasoline/Diesel (GD) blends reduce the soot emissions of diesel engines with the penalty of combustion efficiency. In order to reduce emissions and improve thermal efficiency of diesel engines, blends of GDP (gasoline/diesel/PODEn) were proposed and studied in this work. Experiments were carried out in a diesel engine fueled with pure diesel, GD blends, and GDP blends. The results show that both GD blends and GDP blends have single-stage premixed heat release. GDP blends have shorter ignition delay, lower max pressure rise rate and COVIMEP (coefficient of variation of indicated mean effective pressure) than GD blends. GD blends have lower soot emissions than diesel fuel, while GDP blends have lowest soot emissions and exhibit best NOx-soot trade-off. GDP blends also have higher combustion efficiency and thermal efficiency than GD blends, even slightly higher than diesel fuel.