Effect of fuel injection timing on engine characteristics with an equal volume of 1-heptanol/diesel blend in a CRDI CI engine

Abstract

1-Heptanol (C7H15OH) is a superior and eco-friendly alternative to diesel fuel derived from renewable biomass to address environmental concerns and mitigate fossil fuel depletion. Testing in this research involved using a single-cylinder, four-stroke CRDI diesel engine. The engine ran at a constant speed of 1500 rpm and was fueled with a blend of 50 % 1-heptanol/diesel by volume. The research focused on examining the impact of different injection timings (21°, 23°, and 25 °CA bTDC) specifically, retarded, standard, and advanced timings, as well as varying engine loads of 4, 8 and 12 kg on engine performance, combustion efficiency, and emissions. Experimental test results showed that blending 1-heptanol/diesel fuel led to a substantial decrease in NOx emissions and smoke opacity, which were reduced by 27 % and 26 %, respectively. However, when using a 50 % 1-heptanol/diesel blend and testing with advanced injection timing, there was a 2.26 % decrease in BTE and a 5.1 % increase in BSFC compared to pure diesel. The injection timing advancement improves premixed combustion but increases HC and CO emissions. Research suggests a 50 % blend of 1-Heptanol as a promising renewable fuel for diesel engines, with slight modifications. © 2025 The Authors