Experimental study on the effect of injection strategies on the combustion and emissions characteristic of gasoline/methanol dual-fuel turbocharged engine under high load

Abstract

This study aims to investigate the impact of methanol direct injection strategy on the combustion and emission characteristics of a dual-fuel turbocharged engine running under high load of 1500 rpm. Five methanol injection timings ranging from −330° CA (crank angle) to −60° CA ATDC (after top dead center) were tested under four different methanol energy substation ratios. Based on the experimental results, a suitable injection timing was selected to study the effect of methanol energy substation ratio. The results showed that different injection timings had varying effects on engine combustion and emission characteristics. End of injection timing of methanol (EOI) at −180° CA ATDC resulted in fuller atomization of methanol, which delayed combustion and reduced the combustion rate, with the lowest knock intensity and highest indicated mean effective pressure. However, this timing also had the highest emissions of NOx. Further experiments were conducted at EOI = −180° CA ATDC under eight different energy substation ratios. The results demonstrated that adjusting the injection strategy of methanol can effectively change the engine's performance. The optimal injection strategy was found to be EOI = −180° CA ATDC and an energy substation ratio range of 4.6%–8.9%. This research provides valuable insights into the use of methanol as a fuel and its impact on engine characteristics.