With the announcement of the timetable for banning the sale of fuel vehicles in various countries around the world, and the full efforts of major car companies in the field of new energy vehicles, new energy vehicles ushered in a big explosion in 2018.
Judging from the September new energy vehicle data released by the China Association of Automobile Manufacturers, the production and sales of new energy vehicles in September increased relatively steadily, with a total of 121,000 units sold, a month-on-month increase of 19.8% and a year-on-year increase of 54.8%. Compared with the year-on-year decline in my country’s car sales in September, new energy vehicles can be described as “going against the current”.
While new energy vehicles continue to increase their market share, they have also brought changes and progress in automotive technology. The arrival of new technologies will inevitably lead to the regression or even disappearance of some traditional technologies. So, does the rapid development of new energy vehicles also mean that the era of the end of fuel vehicles is coming? This article will use the transmission, one of the three major parts of the car, to find out.
Transmission is not so important for pure electric vehicles
The transmission is one of the core components of a traditional fuel vehicle. It has two basic functions. One is to cooperate with the clutch to ensure the normal start of the car, and it will not stall due to excessive starting load; The engine is stabilized at the working speed by switching gears (gear ratio). It has a vital impact on the driving experience of the car, but in the field of new energy vehicles, the transmission does not seem to be so important. Because the motor of an electric vehicle can already rely on its own perfect system to drive the vehicle normally, and the transmission has limited effect on improving drivability. If another transmission is added, the weight of the vehicle will increase and the cost will also increase.
At present, most pure electric vehicles in China do not have transmissions in the physical sense. Many people may see the gear levers of some cars and the gear display on the instrument, but in fact those are analog gears catering to consumers. , The motor itself does not need the assistance of the gear transmission mechanism to work stably at various speeds.Also read:https://www.aimeno.com/lithium-battery/226.html
Pure electric vehicles on the market are basically single-speed transmissions, such as Tesla, BMW i3, BAIC Electric Vehicle, Venus Chenfeng, BYD e5, Emgrand EV, Denza, etc. The advantages are: low cost, simple structure and easy installation, low failure rate, small power loss, and small volume. The disadvantage is: when the speed of the electric vehicle reaches the limit, there is no room for improvement, so the speed of the electric vehicle is restricted, and the high-speed economy is not high. Under the condition of the same fixed power, the speed of the electric vehicle using the asynchronous motor is faster, but after matching with the fixed gear ratio transmission, the speed does not increase. Even Tesla, which has strong acceleration, has poor acceleration performance in the middle and rear stages, which is affected by the fixed gear ratio transmission.
In addition, pure electric vehicles cannot be equipped with ordinary transmissions. The main reason is that the size and weight of ordinary transmissions are too large compared with electric vehicles. ;The second is that the transmission efficiency is not high enough! Take the dual-clutch transmission with high transmission efficiency as an example, the actual transmission efficiency is about 87%, which means that the original 100-kilometer cruising range of the battery pack is only 87% after being transmitted to the wheels. kilometers away. At the same time, considering the weight factor of the transmission, the actual cruising range may also be reduced!
The function of the electric motor is much simpler and more powerful than that of the fuel engine. Electric vehicles can run normally without a transmission, so why increase the cost and add a transmission?
Development Trend of Transmission
Analysts at the institute believe that by 2030, electric vehicles will account for more than 80% of China’s auto production. Hybrid vehicles will still be equipped with AT, DCT and ECVT; in the short term, pure electric vehicles will use reducers as the mainstream and two-stage transmissions as the trend. For hybrids, the transmission is still the core component. Both AT and DCT of hybrid vehicles can be equipped, but special modification is required. ECVT has a simple structure, high transmission efficiency, and good comfort. It is foreseeable that after the expiration of patent protection, the market share of ECVT will increase significantly. In the short term, the DCT main drive front and rear solutions are highly feasible, and the long-term trend is BSG+ with a high degree of integration. DCT odd axis motor structure. For pure electric vehicles, the two-stage transmission is the trend. In the short term, due to technical reasons, almost all pure electric vehicle transmissions on the market are single-stage reducers. In the long run, two-stage transmissions can better improve motor efficiency and have better high-speed performance, which will become a trend.
Many people in the industry who agree that the two-stage transmission will be the future development trend also believe that the use of the two-stage transmission can make the motor work more in the high-efficiency area. The reducer is much smaller, which reduces the working current of the motor, reduces the burning loss of the motor, and improves the working efficiency of the motor.Also read:https://www.aimeno-battery.com/products/183.html
Some people in the industry also believe that for pure electric vehicles, in order to increase the traditional ratio and achieve the maximum speed and maximum gradient, the transmission can be improved, and the five-speed transmission can be used to improve the performance of the vehicle. At this stage, the five-speed transmission has achieved industrial development, but the research and development results of the two-speed transmission are obviously not obvious. Therefore, the five-speed transmission can directly apply the existing technology and achievements to reduce the research and development costs. , The requirements for the motor are not high, it may be the main direction of the development of electric vehicles in the future.