Gas engine has certain advantages in energy utilization and emission control, and its thermal efficiency performance is directly related to operating costs, fuel consumption and system output capacity. There are many factors that affect the thermal efficiency of gas engines, mainly involving combustion process, gas compression ratio, fuel quality, intake system design and ignition control strategy.

        First, the compression ratio has a direct impact on thermal efficiency. Generally speaking, the thermal efficiency of gas engines increases with the increase of compression ratio. This is because high compression ratio is helpful to improve the work capacity of gas expansion in the combustion process, thus enhancing the effective work released by unit fuel. Considering the good anti-explosion performance of gas, some engines can design higher compression ratio under the condition of maintaining operation, thus optimizing thermal efficiency.

        Second, the combustion system structure and mixture uniformity are also one of the key factors. Most gas engines use premixed combustion. The higher the uniformity of fuel and air mixing, the more complete the combustion process, which is helpful to improve the heat conversion efficiency. Combustion chamber design, nozzle distribution, flame propagation path and other factors will have an effect on the uniformity of mixture and combustion rate.

        Third, the temperature and pressure management of the intake system are directly related to the combustion efficiency. The gas engine with supercharged intercooling technology can increase the combustion density by compressing the intake air, and indirectly increase the energy release per unit time. On this basis, reasonable control of intake temperature can suppress the occurrence of knocking, so that the engine can work at a better ignition time, thus improving the total thermal efficiency.

        Fourth, the control strategy of ignition system also affects the thermal efficiency performance. Modern gas engines widely use high-energy electronic ignition system and multi-point injection technology, which can control ignition time and energy input more accurately and improve combustion integrity. Proper early ignition is helpful to increase effective work and reduce the influence of unburned gas on thermal efficiency.

        Fifth, the stability of fuel composition and quality can not be ignored. Gas engines usually use natural gas, biogas, synthetic gas and other gases as fuels. The calorific value, moisture content and impurity content of different fuels are directly related to the release efficiency of combustion calorific value. High-purity and low-moisture gas can significantly improve the energy release per unit mass, reduce the risk of carbon deposition, and indirectly improve the thermal efficiency.