Here are the three main power forms of natural gas vehicles (NGVs) and their respective working principles described in English: 1. **Compressed Natural Gas (CNG) Vehicle**: Power Form: CNG is stored in cylinders under high pressure, typically around 20-25 MPa. This compressed state allows for a higher volume of gas to be stored in a relatively small space. Working Principle: Once the CNG vehicle's engine starts, the CNG is fed from the storage cylinder through a hose to a pressure regulator near the engine. The regulator reduces the pressure of the CNG to a level suitable for the engine. The decompressed gas is then sent to a mixer where it combines with air. Sensors and a computer system adjust the mixture of fuel and air to ensure optimal combustion. Finally, the gas-air mixture is injected into the engine's cylinders, where it is ignited by the spark plugs, driving the pistons to produce power. 2. **Liquefied Natural Gas (LNG) Vehicle**: Power Form: LNG is natural gas cooled to -162°C, turning it into a liquid state. This reduces its volume by about 600 times, allowing for efficient storage in specialized tanks. Working Principle: LNG is pumped from the storage tank into a vaporizer that heats the liquid, converting it back to gas. The gas then follows a similar path as in a CNG vehicle, passing through a pressure regulator, mixer, and finally being injected into the engine's cylinders for combustion. 3. **Adsorbed Natural Gas (ANG) Vehicle**: Power Form: ANG uses a porous material, such as activated carbon, to adsorb and store natural gas at relatively low pressures. This allows for the gas to be stored in lightweight containers. Working Principle: As the ANG vehicle's engine operates, the adsorbed gas is gradually released from the porous material into a low-pressure manifold. A pump then boosts the pressure of the gas to a level suitable for the engine. The subsequent steps, including pressure regulation, mixing with air, and ignition, are similar to those in CNG and LNG vehicles. In all three cases, the key working principles involve the safe storage and efficient delivery of natural gas to the engine for combustion, resulting in a cleaner and more efficient mode of transportation.
