Effect of charge air temperature on E85 dual-fuel diesel combustion

Abstract

The scope of this experimental engine study was to explore the effect of charge air temperature on E85 ethanol/gasoline blend dual-fuel combustion. The E85 was injected in the intake manifold, while diesel fuel was direct injected into the cylinder with a common-rail injection system. The study focused on medium and high load conditions at 1500rpm. The diesel injection timing parameters were kept in every test case the same as in the original diesel production engine. The results showed that charge air temperature influenced the ignition delay, the cylinder pressure rise rate (PRR) and the maximum cylinder pressure by altering the E85 combustion phasing, while the changes on the diesel fuel combustion were minor. Lower charge air temperatures allowed higher E85 injection rates without the risk of a too high PRR, especially at high load conditions. The increase of the E85 rate allowed by lower charge air temperature, decreased nitrogen oxide emission, but simultaneously increased carbon monoxide and unburned total hydrocarbon emissions and decreased combustion efficiency.