Here is a brief description of the three types of natural gas vehicles (NGVs) and their working principles in English: 1. **Compressed Natural Gas (CNG) Vehicles**: * **Power Form**: CNG vehicles use compressed natural gas as their main fuel source. The natural gas is compressed to high pressures (typically 20-25 MPa) for efficient storage in on-board tanks. * **Working Principle**: Once the engine starts, CNG from the storage tank is fed through a hose to the engine. A pressure regulator reduces the pressure of the CNG before it enters the mixer. In the mixer, the CNG is combined with air. Sensors and computers adjust the mixture of fuel and air to ensure efficient combustion. The mixture is then introduced into the cylinders through a multi-point sequential injection system, and a spark plug ignites the mixture, pushing the piston and generating power. 2. **Liquefied Natural Gas (LNG) Vehicles**: * **Power Form**: LNG vehicles use liquefied natural gas, which is natural gas cooled to a liquid state for increased energy density and efficient storage. * **Working Principle**: LNG is stored in cryogenic tanks on the vehicle. As the LNG vaporizes, it is warmed and transformed back to its gaseous state. The gas then follows a similar process as CNG vehicles, entering a mixer where it is combined with air, adjusted by sensors and computers, and ignited by a spark plug in the cylinders. 3. **Adsorbed Natural Gas (ANG) Vehicles**: * **Power Form**: ANG vehicles utilize a special adsorbent material (such as activated carbon) to store natural gas at lower pressures than CNG, while maintaining a high gas volume. * **Working Principle**: The ANG system adsorbs the natural gas molecules onto the adsorbent material, allowing for efficient storage in a tank with lower internal pressures. When the gas is needed, it desorbs from the material and enters the engine's fuel system. The rest of the working principle is similar to CNG vehicles, with the mixture of ANG and air being ignited in the cylinders to generate power. Note that these descriptions provide a general overview of the types of natural gas vehicles and their working principles. Specific implementations may vary depending on the vehicle's design and manufacturer.
