How do the energy density and combustion characteristics of different gases affect the performance of gas engines?

1、 The influence of energy density

Power output

Gas with high energy density, such as liquefied natural gas (LNG), can release more energy during combustion. Under the same intake and combustion conditions, using gas with high energy density can provide stronger power output for the engine. For example, in the gas engine of heavy-duty trucks, using LNG compared to compressed natural gas (CNG), due to its higher energy density, can enable the truck to exhibit better power performance when climbing slopes or accelerating at full load.

For some application scenarios that require high power, such as ship propulsion engines, using high-energy density gas can ensure that the ship has sufficient power during navigation and avoid affecting the speed due to insufficient power.

Range of endurance

Gas with high energy density means that it can store more energy with the same storage volume. Taking cars as an example, gas powered vehicles using LNG as fuel typically have a longer range compared to those using CNG. This is because LNG undergoes liquefaction treatment, significantly increasing its volumetric energy density and reducing the hassle of frequent refueling, making it more suitable for applications that require long endurance such as long-distance transportation.

2、 The influence of combustion characteristics

Burning speed

The combustion speed of different gases varies. For example, the combustion rate of hydrogen is much faster than that of methane (the main component of natural gas). Gas with fast combustion speed can complete the combustion process more quickly in the engine. This has a significant impact on the combustion efficiency and power response of the engine. In high-performance engines, appropriate combustion speed can enable the engine to generate greater torque in a short period of time, improving the acceleration performance of the vehicle.

However, if the combustion speed is too fast, it may cause engine detonation and damage to the mechanical components of the engine. Therefore, the design of the engine and the selection of gas need to comprehensively consider the combustion rate, and optimize the combustion process by adjusting parameters such as ignition advance angle.

flame temperature 

The flame temperature generated by the combustion of different gases varies. For example, the flame temperature of hydrogen combustion is higher than that of natural gas combustion. A higher flame temperature can improve the thermal efficiency of the engine, converting more fuel energy into useful mechanical energy. However, at the same time, excessively high flame temperatures can also increase the thermal load on engine components, placing higher demands on engine materials and cooling systems.

The control of flame temperature is particularly important in applications such as gas turbines. If the flame temperature is too high, it may cause damage to key components such as turbine blades, affecting the reliability and service life of the engine.

Combustion stability

The combustion stability of gas is crucial for the normal operation of the engine. Some gases, such as propane, have good combustion stability and can burn stably over a wide range of operating conditions. This enables the engine to maintain good performance under different loads and speeds.

For gases with poor combustion stability, incomplete combustion and engine stalling may occur under extreme operating conditions such as low engine load or high engine speed. This requires the engine to be equipped with more advanced combustion control systems, such as electronic fuel injection systems and variable valve timing systems, to improve the combustion stability of gas and ensure the stable performance of the engine.