Investigation of the drop-in capabilities of a renewable 1-Octanol based E-fuel for heavy-duty engine applications

Abstract

This article presents the results of an investigation of neat 1-Octanol and its blends with Diesel, which can be potential drop-in fuels for heavy-duty compression ignition engines. Fuel blends consisting of 10 %, 20 %, and 30 % 1-Octanol by volume in Diesel, including neat 1-Octanol, were investigated for ignition and combustion performances. The ignition behavior was assessed using a constant-volume combustion-chamber-based ignition tester. The experimental investigation was conducted on a heavy-duty single-cylinder engine by varying the combustion center. In addition, injection-rate shaping was performed to understand the effects of various injection-rate shapes, namely square, ramp, and boot rate shapes, on the performance of neat 1-Octanol.The ignition tester results indicated an increased ignition sensitivity of neat 1-Octanol towards the chamber pressure and temperature compared to that of Diesel. At an elevated chamber temperature (650 °C) and pressure (20 bar), the ignition delay of neat 1-Octanol approaches closer to that of Diesel. Engine experiments revealed an improved thermal efficiency with neat 1-Octanol and its blends by up to 1.2 %, owing to their improved mixture homogenization capabilities. Furthermore, neat 1-Octanol and its blend led to a drastic reduction in smoke and carbon monoxide. In addition, it results in the highest peak during the premixed heat release, and with a square injection-rate shape, an additional minor improvement in thermal efficiency was observed. The relative changes in carbon monoxide and hydrocarbon emissions between the injection-rate shapes were negligible. At higher load, the boot-rate shape results in lower NOx formation than the square-rate shape at an almost identical thermal efficiency. Overall, the 10 % 1-Octanol, 20 % 1-Octanol and 30 % 1-Octanol blends, which fulfill the Cetane number requirements for the given fuel norms, can be used as drop-in fuels, as they exhibit a comparable or even better performance than Diesel.