The Effects of Ignition Delay and Fuel Injection Duration on Sparked-Spray Combustion Using Gasoline and Methanol in the Atmospheric Environment

The sparked-spray method represents a novel combustion approach that employs an electrical spark to directly ignite fuel spray through cooperative control of fuel injection and spark ignition timing, forming an intense flame kernel for enhanced combustion performance. This method offers potential advantages in combustion efficiency and flame propagation characteristics compared to conventional ignition strategies. This paper investigated the effects of ignition delay and fuel injection duration on sparked-spray combustion characteristics using gasoline and methanol as test fuels in an atmospheric environment through high-speed photography. The study systematically examined the relationship between ignition timing parameters and combustion performance by analyzing projected flame area as a quantitative measure of flame intensity. Experimental results demonstrate that optimal ignition occurs when the ignition delay is 1.2 ms or 1.5 ms, where the spray is more readily ignited and produces larger projected flame areas under identical injection duration conditions. Furthermore, regardless of injection duration variations, methanol spray consistently exhibits superior combustion characteristics, generating larger projected flame areas and longer flame survival duration compared to gasoline spray.