Gas Engines: Energy Utilization Advantages and Factors Influencing Thermal Efficiency

Gas engines offer distinct advantages in energy utilization and emission control, and their thermal efficiency is directly linked to operating costs, fuel consumption, and system performance. Numerous factors influence the thermal efficiency of gas engines, primarily including the combustion process, gas compression ratio, fuel quality, gas intake system design, and ignition control strategy.

1. Compression Ratio

The compression ratio directly impacts thermal efficiency. Generally, the thermal efficiency of gas engines increases as the compression ratio rises. This is because a higher compression ratio enhances the expansion work of gas during combustion, thereby boosting the effective power output per unit of fuel. Given the excellent anti-knock properties of gas, some engines can be designed with a higher compression ratio under feasible maintenance conditions to optimize thermal efficiency.

2. Combustion System Structure and Mixture Homogeneity

The structure of the combustion system and the homogeneity of the fuel-air mixture are also key factors. Gas engines primarily adopt a pre-mixed combustion mode. The higher the homogeneity of the mixture between fuel and air, the more complete the combustion process, which helps improve heat conversion efficiency. Factors such as the design of the combustion chamber, injector distribution, and flame propagation path all affect the homogeneity and burning rate of the mixture.

3. Intake System Temperature and Pressure Control

The control of temperature and pressure in the intake system is directly related to combustion efficiency. Gas engines using charge air cooling technology increase the combustion density by compressing the intake gas, indirectly enhancing energy release per unit time. Based on this, rational control of intake temperature can suppress the occurrence of detonation, allowing the engine to operate at a more optimal ignition timing and thus improving overall thermal efficiency.

4. Ignition System Control Strategy

The control strategy of the ignition system also influences thermal efficiency. Modern gas engines widely adopt high-energy electronic ignition systems and multi-point injection technology, which can more precisely control ignition timing and energy consumption to improve combustion integrity. Appropriately advancing ignition timing helps enhance effective work output and reduce the impact of unburned gases on thermal efficiency.

5. Fuel Composition and Quality Stability

The composition and quality stability of fuel cannot be ignored. Gas engines typically use fuels such as natural gas, biogas, and syngas. The calorific value, moisture content, and impurity content of different fuel types are directly related to the efficiency of heat release during combustion. Gas with high purity and low water content can significantly improve energy output per unit mass, reduce the risk of carbon deposition, and indirectly enhance thermal efficiency