Types of new energy vehicles 1
Gasoline and diesel are the energy sources of traditional internal combustion engine vehicles, and vehicles powered by other energy sources can be called new energy vehicles. So far, the world has introduced alternative fuels such as methanol, ethanol, hydrogen, compressed natural gas and liquefied petroleum gas, as well as new energy vehicles such as electric and hybrid vehicles.
(1) Natural gas and liquefied petroleum gas vehicles
The gas has single composition, high purity, can be evenly mixed with air and burns completely, the emission of CO and particulates is low, and the engine starts and runs better at low temperature. The disadvantages are poorer transport performance than liquid fuels, lower volumetric efficiency of the engine, longer ignition delay and reduced power. At present, most of these vehicles use a dual-fuel system, that is, a compressed natural gas or liquefied petroleum gas system and a gasoline or diesel combustion system, which can easily transition from one system to the other. This type of vehicle is mainly used in urban buses.
(2) Alcohol fuel vehicles
The most widely used is ethanol. Ethanol has a wide range of sources and mature production technology. The latest technology to produce ethanol from cellulose raw materials includes almost all agricultural and forestry wastes, urban domestic organic wastes and industrial organic wastes. At present, alcohol vehicles are mostly driven by fuel blended with ethanol and gasoline or some oil, which does not need to modify the engine, but also has a good effect on energy saving and pollution reduction, but this blended fuel must obtain the same power as gasoline or diesel , the amount of fuel injection must be increased. When the alcohol blending rate reaches 20%, the compression ratio and ignition advance angle of the engine should be changed. The theoretical air-fuel ratio of ethanol fuel is low, the requirements for the engine intake system are not high, the self-ignition performance is poor, the octane number is high, and it has high resistance Explosive, good volatility, uniform distribution of mixed gas and high thermal efficiency, automobile exhaust pollution can be reduced by more than 30%.
(3) Hydrogen fuel vehicles
As a vehicle fuel, hydrogen has a high octane number and high engine thermal efficiency; the engine can burn stably within a large range of air excess coefficient; the ignition energy is low, less than 1/10 of the lowest ignition energy of gasoline, and the flame of hydrogen fuel spreads Fast speed; easy to start at low temperature, but there are problems such as tempering, early ignition and poor combustion control when used on the engine. The storage and transportation performance of hydrogen is very poor, and its boiling point is -253 ℃. It is expensive to store in liquid form and is not suitable for long-term storage. Radon is produced from natural gas, coal and water. So far, the cost and energy consumption of these hydrogen production methods are high, and it is difficult to produce large-scale gas for vehicle fuel. Therefore, gas must be solved to reduce production costs and storage and transportation before it can gradually become practical.
