Effect of Fuel Injection Strategies on Performance, Combustion, and Emission Characteristics of Diesel–Diethyl Ether–Fueled Compression Ignition Engine

<div>This experimental study compared a blend of diesel–DEE (DEE 40% v/v in diesel) with baseline diesel. This experimental study assesses different fuel injection strategies for controlling the in-cylinder charge stratification, such as single, double, and triple injections. The peak in-cylinder pressure under the partially premixed combustion mode was higher than conventional diesel combustion. Higher in-cylinder pressure with increasing dwell time was observed under triple injections. Retarding pilot injections increased the peak in-cylinder pressure. Conventional diesel combustion mode exhibited the highest brake thermal efficiency and lowest emissions with all injection strategies. A longer dwell time of 12° CA showed higher brake thermal efficiency, nitric oxide, and carbon monoxide emissions, whereas hydrocarbon emissions were lower compared to a shorter dwell time of 6° CA. Hydrocarbon and carbon monoxide emissions increased, but nitric oxide and brake thermal efficiency were reduced by advancing pilot injections. The diesel–DEE blend exhibited slightly lower brake thermal efficiency than baseline diesel at all injection strategies, except for the conventional diesel combustion mode. Diesel–DEE blend exhibited higher hydrocarbon and carbon monoxide emissions than baseline diesel, but nitric oxide emissions were lower.</div>