Optimising the Particulate Emission Characteristics of a Dual-Fuel Spark Ignition Engine by Changing the Gasoline Direct Injection Strategy

In the current global scenario, it is essential to find more effective and practical solutions to mitigate the problem of particulate emissions from vehicles. In this research, particulate emission characteristics with changing GDI pressure or applying a split GDI strategy with different second injection timings were initially explored in a Dual-Fuel Spark Ignition (DFSI) engine, which employs Ethanol Port Injection (EPI) plus Gasoline Direct Injection (GDI). The experimental results show that by increasing GDI pressure (Pɢᴅɪ) from 5.5 MPa to 18 MPa, ignition delay (θꜰ) shows a small decrease of 0.68 degrees. The parameters, such as maximum in-cylinder temperature (Tᴍɪ) and exhaust gas temperature (Tᴇɢ), each increase by 53.75 K and 13.84 K. An apparent reduction of 59.5% and 36.26% was achieved for the concentrations of particulate number (Nᴘ) and particulate mass (Mᴘ), respectively. Particulate emissions are effectively reduced by a split GDI strategy with an appropriate range of second injection timing (tɢᴅɪ2). Under tɢᴅɪ2 = −260 °CA, Nᴘ and Mᴘ concentrations exhibit a relatively lower level. However, by delaying tɢᴅɪ2 from −260 °CA to −140 °CA, there is an increase of more than 60% in Nᴘ concentration. The research findings help offer new and valuable insights into optimising particulate number and mass emissions from DFSI engines. Moreover, the findings could contribute novel and valuable insights into the optimisation of particulate emission characteristics in DFSI engines.