Recently, it has been questioned that electric vehicles, which are uneconomical and environmentally friendly, have become a big hit under the instigation of the levers. There are also many people who don’t know the truth, and they sneak a sneer at the electric cars.
Since so many people have questioned electric vehicles, is it really worthwhile for the country to vigorously develop electric vehicles? Who is supporting the electric car? The following is an analysis of the challenges raised by the levers.
Bars mentioned that the zero emissions of electric vehicles are completely misleading. Under the energy structure of China’s main thermal power generation, electric vehicles are not more environmentally friendly than traditional vehicles. Then we can simply compare the energy efficiency of gasoline vehicles and electric vehicles, and estimate the overall efficiency of vehicles from the two aspects of efficiency and vehicle efficiency.
Gasoline vehicles: The efficiency of converting the mined oil into gasoline is about 80%~90%; while the efficiency of the internal combustion engine in the ideal speed range is about 30%~40%. In actual driving, there is still idle speed, acceleration and deceleration. Such conditions, the actual vehicle end efficiency may be less than 20%. That is, the comprehensive energy efficiency of the gasoline car is less than 18%.
Electric vehicles: The energy conversion efficiency of thermal power generation is about 40%; while the charging system converts electrical energy into chemical energy stored in the battery, and then the battery converts chemical energy into electrical energy and outputs it to the motor, which converts the electrical energy into mechanical energy to drive the wheel. The efficiency of the entire electric drive assembly energy transfer can reach more than 80%. Therefore, the overall energy efficiency of electric vehicles is roughly 32%.
According to the above calculation, the preliminary conclusion is that the electric vehicle can reach twice the energy efficiency of the internal combustion engine.
Moreover, the electric vehicle has no problem of exhaust emission at all, and the discharge in the thermal power generation process can be concentratedly processed, which is obviously more reasonable than the exhaust gas of the internal combustion engine and the place.
Of course, it may be suggested that the current hybrid vehicle HEV can make the internal combustion engine work more in the ideal speed range, and it is not impossible to achieve energy efficiency close to 40% at the vehicle end.
Indeed, at this stage, the HEV/PHEV can further improve the efficiency of the internal combustion engine through the assistance of the electric assembly, and is close to the electric vehicle in terms of energy efficiency. However, the thermodynamic principle determines the theoretical efficiency limit of the internal combustion engine.
The principle of an internal combustion engine is to convert chemical energy into heat to expand the gas, and thereby generate mechanical energy to drive the wheel. Therefore, the process of converting chemical energy into mechanical energy is inevitably accompanied by a large amount of heat energy loss.
According to the principle of the Carnot engine, it can be concluded that the limit of energy efficiency of the gasoline engine is not more than 50%. The efficiency of power generation can be gradually improved through the transformation of the energy structure in the future, making the electric vehicles more and more environmentally friendly.
So who is supporting the electric car? His name is Nikola Leonard Sadi Kano, founder of thermodynamics.