This study investigated combustion characteristics paying particular attention to a mass flow rate pattern under stratification charge mode. The mass flow rate was changed using two injector drivers with different operating characteristics for an injector. These injection systems were employed in an optical single-cylinder engine. Three different injection timings under late injection modes were set to simulate the stratification charge combustion. To obtain the mass flow rate, the experiments of fuel metering and injection rate measurement were performed with a fixed injection quantity. In-cylinder pressure was measured to analyze combustion characteristics. Initial flame size and its developments were also visualized. In addition, the mixture distribution prior to ignition was obtained using PLIF technique. As the mass flow rate has a higher value, more stable and faster combustion was achieved. The mixture distribution showed more uniform and higher concentration in the bowl mear the spark plug as the mass flow rate increases.