Improvements of Thermal Efficiency and Exhaust Gas Emissions in Diesel Combustion with Oxygenated Fuels

Abstract

The effects of the oxygen content in fuels on the combustion characteristics and exhaust gas emissions were investigated in a diesel engine. The oxygen contents were widely varied with the blend ratio of diglyme, dimethyl carbonate, and diesel fuel, maintaining similar ignitabilities. With increasing oxygen contents, the degree of constant volume heat release increased with reduction in afterburning, resulting in higher indicated thermal efficiencies. However, the indicated thermal efficiency showed a maximum at around 27 mass% of the oxygen content in fuel and further increases in the oxygen contents resulted in lower indicated thermal efficiencies due to larger cooling losses.