When it comes to the theoretical mileage of electric vehicles, many people only use one word to describe it - virtual.
Theoretical endurance is to facilitate comparison and reference, simulating the theoretical value of the real road driving test, and there are three common test methods:
NEDC (New European Drivig Cycle, New European Driving Cycle), this test simulates the working conditions of cities and suburbs, including speed and drag, the theoretical value of the test is generally relatively high, and it is also a test method that car companies prefer to use, which is of little reference significance to users.
WLTP (World Light Vehicle Test Procedure), which is relatively stricter than the NEDC test, includes speed, resistance, gear and vehicle weight, and the theoretical value of the test is slightly lower than that of the NEDC.
EPA (U.S. Environmental Protection Agency, short for U.S. Environmental Protection Agency), the test is more accurate, the theoretical value is closer to the actual working conditions, compared to the first two, this value has the greatest reference significance.
Despite this, the real road endurance will still be different from the theoretical value, and many people give different values, which actually has a lot to do with personal driving habits.
Electric vehicles are more energy efficient than fuel vehicles, and in general, the energy efficiency of electric vehicles can reach 90%, but fuel vehicles are only about 60%.
Speaking of this, some people may begin to refute it: how much discount is the winter and summer endurance, and how much is the high-speed endurance discounted? Today's article will be discussed on a case-by-case basis.
Pete Bishop, chief technology officer at Silver Power Systems, an electrical systems design company specializing in battery analysis for electric vehicles, created a spreadsheet detailing the power usage of more than 50 components and systems in electric vehicles, calculating an approximate range reduction in kilometers traveled per hour for each system based on an EV database.
Due to the large amount of data in the table, Xiaobian only summarized the energy consumption and mileage loss of several factors that everyone is more concerned about.
First of all, look at the heating and cooling energy consumption of the carriage and the mileage loss. Bishop's calculations take into account circulation fans, heating and cooling systems, heated front and rear windows, heated mirrors, heated seats, and heated steering wheels.
Cabin heating and cooling systems use the most power in this category, requiring up to 3 kW and 4 kW respectively, which reduces the range of an average electric vehicle by 8.3 km to 11.1 km per hour.
If only the seat is heated, it can save a lot of energy consumption, each seat heating consumes only 50 Wh, if you open two, it means that the car only reduces the cruising range of 560 meters per hour, which is a more effective way to keep warm and energy-saving.
Next look at the heating and cooling of the electric vehicle battery system, because the ambient temperature will affect the electrochemical reaction of the battery, thereby affecting the performance, so now the electric vehicle is equipped with a battery temperature control system, it cools the battery in a high temperature environment, heats the battery in a low temperature environment, and strives to ensure that the operation of the battery is always controlled in a constant temperature environment.
Heating and cooling battery packs are one of the largest energy consumption consumption of electric vehicle batteries, and when the ambient temperature is close to optimal, the range of heating and cooling power consumption can be several hundred watts, 1-2 kW when the environment is very hot or cold, even up to 5kW or more if the vehicle is started in a very cold situation, and the battery needs to be heated by a resistance heater.
For the specific mileage loss caused by heating and cooling the battery, please read the article "Breaking Cognition: How Much the Mileage Loss of 4200 Electric Vehicles Measured in Winter and Summer" was.
Let's look at the breakdown of air resistance and speed on the range. On the highway, the biggest energy loss to date is air resistance, taking Tesla's Model 3 as an example, with a drag coefficient of 0.23 and a frontal area of 2.22 square meters, requiring 9.5 kW of power to overcome air resistance.
Coupled with the consideration of tire friction, the comprehensive efficiency of the inverter and the motor, it takes about 11 kW of power to reach a speed of 110 km / h, the speed is doubled, the resistance will increase by four times, therefore, a slight reduction in speed can save more energy, such as reducing the speed from 110 km / h to 105 km / h, you can reduce the energy consumption of about 8.4%, driving on high speed slightly reduced speed will make the car travel farther.
Finally, look at the assist system, listening to an hour of song reduces the mileage by about 9 meters per hour; the energy consumption of brakes, power steering motors and suspension compressors is also relatively low, reducing the mileage of about 500 meters per hour; and the energy consumption of the headlights is reduced by about 270 meters per hour. Of course, there are also factors such as the weight of the passenger load, which are not listed one by one.
All of the above calculations are based on the average efficiency of electric vehicles at 180wh/km.
All in all, the factor that has the greatest impact on the range of an electric vehicle is ambient temperature, followed by speed.
This article is the original of science and technology cool probe, plagiarism must be investigated!