Effects of different main injection timings and injection pressures on combustion and emissions of diesel-THF-ethanol blended fuel

Abstract

ABSTRACT The effects of additives tetrahydrofuran (THF) and ethanol on combustion, performance and emissions were researched on a six-cylinder turbocharged diesel engine with varying injection strategies. Four fuels were tested, i.e. pure diesel, T15E0, T5E10, and T5E20. Under low load, the maximum cylinder pressure of blended fuel decreased and that of T15E0 decreased with the maximum decrease of 3.35%, from 6.56 MPa to 6.34 MPa. The maximum cylinder pressure was also reduced by 4.24% at most under high load, from 9.90 MPa to 9.48 MPa. With the addition of tetrahydrofuran, the brake specific fuel consumption (BSFC) increased, and the brake thermal efficiency (BTE) decreased. In comparison to pure diesel, the addition of 20% ethanol increased BTE from 35.4% to 35.9%, which was a 1.34% rise. For various injection strategies, the optimized soot emissions of T5E20 decreased by 66.94%, from 0.00289 g/kW·h to 0.00096 g/kW·h, while the maximum increase ratio of NOx emissions was 9.67%, from 9.88 g/kW·h to 10.84 g/kW·h. T5E20 has the potential to increase BTE while decreasing NOx and soot emissions concurrently. The results indicate that tetrahydrofuran is a good cosolvent for diesel-ethanol blended fuel, and ethanol exhibits good performance as the principal component of the blended fuel.