An Investigation of Optimal Combustion Duration in Turbocharged Gasoline Engines

This study analyzed the influence of combustion duration on the output power, fuel efficiency, and emission levels of a turbocharged gasoline engine with the aim of identifying the optimal duration for enhancing engine performance while minimizing environmental impact. The simulation was conducted using the AVL-Boost software, where various combustion durations were tested to evaluate their effects on key engine parameters, including torque, power output, Indicated Mean Effective Pressure (IMEP), Brake Mean Effective Pressure (BMEP), and pollutant emissions such as CO, NOx, and hydrocarbons. The results indicated that a combustion duration between 50° and 60° Crank Angle (CA) yielded optimal performance. Within this range, the torque values varied from 52.4 to 54.19 Nm, the power output reached 6.81 kW, and the IMEP and BMEP were recorded at 3.5137–3.5131 bar and 3.4137–3.4131 bar, respectively. Moreover, both fuel consumption and residual gas fraction were significantly reduced. Specifically, the lowest fuel consumption was observed at 50° CA (33.9577 g/Wh) and 60° CA (33.909 g/Wh), whereas the residual gas fraction decreased progressively from 0.3761 at 50° CA to 0.3743 at 70° CA. Regarding emissions, the lowest concentrations of hydrocarbons and NOx were achieved at 50° CA recorded at 1.7212 and 4.0987 g/kWh, respectively. However, CO emissions peaked at the same CA, reaching 0.003725 g/kWh. Despite the slight increase in CO, 50° CA is still considered the optimal combustion duration, as it delivers the highest engine performance while maintaining the lowest total emission levels.