Study on combustion stability of a miniature reciprocating piston internal combustion engine

The combustion of a micro-piston internal combustion engine with platinum wire glow ignition is diagnosed. The results show that the combustion starting point of the micro piston internal combustion engine varies greatly, and the combustion duration is various and long. The coefficient of variation of p(max) is as high as 28.5%, the combustion stability is poor. Therefore, it is suggested to improve the thermal environment in the cylinder to improve the combustion stability. One method is to increase the temperature in the cylinder to reduce the duration and the cyclic variation of combustion. The other method is to increase the temperature of the platinum wire to improve the stability of the starting point of combustion and to reduce the cyclic variation of combustion. The test results show that with the increase in the cylinder body temperature, the distribution of combustion starting point is more concentrated, and the coefficient of variation of p(max) decreases by about 38.6%. The stability of combustion increases. So the combustion stability can be improved by appropriately increasing the temperature of cylinder body. With the increase temperature of the platinum wire, the ignition and combustion will be facilitated and the combustion stability will be improved. At the same time, the movement of the gas near the platinum wire will be accelerated, which gives rise to affect the flame-kernel development and flame propagation. The ignition points will become scattered, which increases the instability of combustion.