A numerical simulation was conducted for the piston dynamic characteristics

cylinder pressure and temperature as well as NOx emissions of a two-stroke gasoline free piston linear generator (FPLG). The source and formation mechanism of NOx emissions were analyzed based on the characteristics of the FPLG. The influence of spark ignition timing and combustion duration on cylinder pressure and temperature as well as NOx emissions was calculated and analyzed by using Matlab/Simulink. Results show that when the ignition timing is 9°～54° before TDC

with a combustion duration of 36°～108° (when sparking time before reaching top dead center is 0 ms～6 ms and combustion duration is 4 ms～ 12 ms)

increasing the ignition timing and reducing the combustion duration can increase the cylinder pressure and temperature

with a rapid increase in NOxemissions.