In the previous round, I talked about the powerful ability of a motor and listed a lot of evidence that electric vehicles could spike the super run. However, today's story has been reversed, no matter how fast the electric car starts to accelerate, it has a fatal weakness that cannot be overlooked. The speed performance is general, and the most direct object related to this indicator is this time to talk. "Transmission", careful you may find that I put a quotation mark on it, we use this name to begin the following interpretation.
Conclusion First throw: from a broad perspective, the electric vehicle is equipped with a fixed gear ratio gearbox, which is a kind of gearbox; in a narrow sense, this so-called fixed gear is more than a single gear. Speed reducer, which is also a more accurate title. Therefore, at the very beginning of the article, I must clarify that even if it is called a gearbox, it cannot be compared with the gearbox of a traditional internal combustion engine car.
At present, there are more and more pure electric vehicles on the market, and new energy sources are also an irreversible important development trend in the future. Ever since then, we have seen unremitting efforts and explorations by Sanjin Electric (batteries, electric motors, and electronic control) in order to increase mileage and driving performance. However, the gearbox level seems to have been neglected by the people. On the one hand, the single speed reducer has a simple structure and is easy to install and carry, and the most important thing is that it has enough to meet the needs of the current stage, so naturally it is not a matter of urgency.
There is no shortage of gold and no one is perfect. The advantages of single speed reducer are very prominent, and the disadvantages are also obvious. Firstly, “Lee”, single-speed reducer is low in cost, and the structure is very simple. Installation calibration is not a problem, and it has the characteristics of small size and light weight, which is very important for cruising range. Let's talk about the “disadvantages”. We once said that the hundred kilometers of the Tesla Model S P100 D can accelerate the Lamborghini Huracan, but what if the two fight together? The former is the flagship model of the Model S. Under the premise of maximum power leading nearly 150 kW, the top speed of 250 km/h may be much worse than the latter's 325 km/h.
The data is talkative. It tells us that although the electric car reaches the speed limit at the start, after reaching a certain speed, the electric car will be in the middle and late stages because there is no multi-tooth ratio gearbox to help release the torque on the wheel. The weakness of the unit, and the inadequacy of the unit's battery life, has become increasingly prominent. This is the biggest flaw and short board of the fixed gear ratio transmission. If you think about it, if you can add a gear with a bigger gear ratio, the results will be very different.
Not to mention that Tesla's first model, the Roadster, did that. Although it was actually only 1.5AT, it could directly reflect Tesla's demand for gearboxes. After all, this is a The pursuit of performance of electric vehicles. However, the combination of a 180kW motor and a 2-speed gearbox didn't last long. Tesla soon gave up on this option. The benefits of the many single-speed gearboxes mentioned here became its shortcomings. As a result, Tesla had to switch to larger motors and batteries to meet the demand for vehicle driving performance.
[Model S work curve]
Then new problems have come, why electric vehicles can ignore the existence of gearboxes, even to the point of despising. Before giving the answer, let's take a look at the working curve of the Tesla Model S above. The ordinate is power and torque, and the abscissa is speed. The details of the specific diagrams are not described here. Let's take a look at the map. In short, in the vast majority of our daily driving situations, it is sufficient for electric vehicles to rely on the torque output of this single speed reducer.
However, the conventional internal combustion engine vehicle is just the opposite. Because the low torque of the internal combustion engine is very weak, it is not possible to start at zero speed. This means that there is an “idle” condition. The meaning is because the vehicle needs a larger reduction ratio. Electric cars do not need. In addition, the internal combustion engine in the smooth area, the maximum power output area and the energy-saving zone are very fine in the three sections, and the range of each section is also relatively narrow, so the gearbox must be used to adjust the reduction ratio to achieve the most appropriate speed, which is for driving Performance is critical. However, these areas of the motor are quite broad. For example, the maximum speed of the Model S can reach 16,000 rpm. Dare to ask which fuel vehicle can reach this level.
Therefore, in order to optimize the various operating conditions not necessary to optimize, increase the additional weight brought by the transmission, shift stalls, transmission losses, high costs and the impact on the endurance, obviously not as good as to use a single-phase current speed enough Reducer, which is the fundamental reason why the fixed gear is so widely used than the gearbox.
More than two years ago, a company named Drive System Design announced that it will develop a multi-tooth ratio gearbox, and AVL, Delta Racing, GKN, Jaguar Land Rover, India Tata Steel, Zytek and other companies A joint venture investment consortium was also set up for this project, and this was because of the world's first multi-tooth ratio gearbox for new energy vehicles.
The internal gearbox, code-named MSYS, is mainly developed for the development of electric vehicles and hybrid vehicles. There are three gears that are expected to be mass-produced this year. According to the plan, the company will also develop a more advanced and applicable range to completely cover electric vehicles. Multi-tooth ratio gearbox. However, this gearbox also faces many difficulties, such as how to reduce the weight, reduce the size, and apply to the needs of high-performance electric vehicles.
Written in the end: Whether it is the traditional car companies or new car builders, many of them regard electric sports cars or performance cars as their core business, such as Weilai EP9 and Ai Chi high-performance super running. Therefore, on the road to continuous maturation and upgrading of batteries and motors, if the gearbox can keep up with the pace of the team, it will be a great advantage for the performance of electric vehicles, and it will also become a new development opportunity in the field of new energy.
