Exploiting a new combustion regime using a split partially premixed compression ignition engine fueled with n-butanol/diesel

Abstract

An experimental investigation has been carried out to explore a novel combustion regime. This regime involves the utilization of a split injection partially premixed combustion (PPC) strategy in combination with DB20 fuel, which consists of 20 % n-butanol and 80 % diesel. The primary objective of this investigation is to assess how variations in pilot-main intervals (PMIs) and pilot-main injection ratios (PIRs) affect the emissions, combustion characteristics, and overall performance of a 4-cylinder turbocharged CRDI engine at various loads. Experimental results show that a split injection strategy combined with DB20 fuel reduces the maximum pressure rise (or combustion noise) rate while reducing NOx and smoke simultaneously compared to single-injection PPCI engines. A 20.1 % reduction in NOX emissions was observed at 20° CA PMI of 2 bar BMEP load and an 11.1 % reduction at 10° CA PMI of 6 bar BMEP load, respectively, compared to a single injection PPCI engine. There is a greater sensitivity to PMI when calculating the brake thermal efficiency (BTE) of DB20 blended fuel. In addition, it was observed that the split injection PPCI engine, powered by DB20 blend fuel, showed a 4.78 % increase in BTE for 20 % PIR and 20° CA PMI under 6 bar BMEP engine load.