天然ガスパイロット燃料着火方式における着火・燃焼特性に関する基礎研究 - パイロット燃料の噴射パラメータがメタン-空気予混合気の着火・燃焼特性へ与える効果

抄録

  Natural gas engines have a potential to contribute to achieving lower GHG emissions compared with conventional marine diesel oil engines. In the case of premixed combustion of natural gas, a pilot fuel ignition system which has multiple ignition effects is mounted on a marine natural gas engine with large bore size cylinders to shorten combustion duration.

  However, it is difficult for a conventional pilot fuel injection system to control ignition under high load fluctuation. This is because the ignition delay of pilot fuel is affected by the equivalence ratio of methane/air mixture. In this study, the authors investigated the effect of pilot fuel injection strategies on the ignition and combustion characteristics of methane/air mixture. A split pilot fuel injection strategy was also assessed using a high response solenoid fuel injector for common rail diesel engines. The results showed that this strategy impacted flame propagation start time, pressure rise rate, and ignition position.