Experimental investigation to assess the efficacy of gasoline surrogates with engine testing

The formulation of effective gasoline surrogates is a challenging task due to advanced combustion strategies, engine design and variable operating conditions in spark-ignition engines. In earlier studies, the gasoline surrogates with iso-octane, n-heptane and toluene blends were designed to closely match the commercial gasoline fuels based on their laminar burning velocity variation and ignition delay time measurements. A new approach of proposing the next generation gasoline surrogates is investigated in the present study with direct testing of these surrogates in a real SI engine. The present study helps in assessing the efficacy of proposed gasoline surrogates in a real engine. The combustion, performance, and emission characteristics of proposed gasoline surrogates are compared with the commercially available gasoline fuels. A total of 10 (named A to F) surrogates were investigated with variable percentage of iso-octane, n-heptane and toluene. All the tested surrogates were successfully tested in a multi-cylinder engine. The result shows that, SF and SG are suitable to reproduce the combustion and emission characteristics of commercially available gasolines during detailed engine testing. It is observed that surrogate F and G results are more aligned with the commercial gasoline fuels thus representing the commercial gasoline more closely and can use further for validation and modeling of IC engines through the application of detailed kinetic models. However, a significant change was observed for other tested surrogates.