Ignition characteristics of a stirling engine in the oxygen and air modes

Stirling engine is characterized by its strong fuel adaptability, making it versatile across various operational scenarios. By operating the Stirling engine at high pressure O 2 /CO 2 environment, the carbon dioxide concentration in the combustion products can be greatly increased, which is conducive to carbon capture. To improve the performance of Stirling engine, the ignition conditions of Stirling engine are compared in two combustion modes (the O 2 /CO 2 combustion mode and air/CO 2 combustion mode). By simulating the ignition process of the Stirling engine in the two modes, the effects of different ignition power, ignition duration, and ignition position on the ignition process during engine start are analyzed. Moreover, the accuracy of the model is verified by experimental results. The findings indicate that in the process of restarting, the igniter is not required, and the ignition can be achieved by preheating in the cylinder. This discovery provides a way to improve the starting efficiency of Stirling engine. In the start process, the ignition success can be achieved by extending the ignition duration or increasing the ignition power, but there is a minimum ignition power limit of 900 W in the oxygen mode and 200 W in the air mode. Ignition position has significant influences on ignition success rate. Too low ignition position will cause the flame core to extinguish under the wash of high-speed air flow, and too high ignition position will prevent the spread of flame, and therefore neither condition will result in successful ignition.