Wuling Hongguang does not need to step on the clutch, and electric vehicles also have gearboxes? Bosch is not as simple as you think!

The 2020 Bosch Automotive and Intelligent Transportation Technology Innovation Experience Day event was held at the Donghai Automobile Testing Technology Center in Lianyungang. There was a lot of technological content on site, including 5G and vehicle-road collaboration in the field of autonomous driving... Topics include silicon carbide chips, hydrogen fuel cell technology, and smart cockpits that have appeared at the Beijing Auto Show before (please click here to read related content).

But what the editor is more concerned about is the innovative technologies that we can enjoy not far away, including the CVT4EV gearbox developed by Bosch for electric vehicles, as well as wired steering and clutch control... aspect technology.

The efficiency medicine of electric vehicles: CVT4EV

Most electric vehicles currently on the market are not equipped with variable speed gearboxes. The reason is that the speed of the electric motor can reach tens of thousands of rpm, and the torque can It reaches a peak when starting, which is enough to push the car to a certain speed.

But the problem is that when the motor speed reaches a certain range, the winding inductance, counter electromotive force, and external resistance... factors will cause the motor torque to decline quickly. This is also the reason why electric vehicles will drive at high speeds. The reason for getting tired.

More importantly, high motor speed = high power consumption, so car manufacturers have to equip their cars with larger capacity and heavier battery packs. Therefore, some high-end electric cars that focus more on performance such as PORSCHE ?Taycan...will be equipped with a two-speed transmission.

But Bosch exhibited the CVT4EV gearbox specially developed for electric vehicles at this event, which is very topical!

Because CVT has the capability of continuously variable transmission, it can flexibly adjust between a wide range of speed ratios to amplify the torque required for starting the vehicle, or to allow the motor to drive the vehicle at a lower speed to run at high speeds. Either way, for example, CVT4EV can increase the car's top speed by 10% and increase power consumption/output efficiency by 4%.

After actually experiencing the Chery Arrizo 5e that has been "modified" with a CVT4EV gearbox, it can be clearly felt that this car has CVT blessing, and the starting acceleration feeling becomes closer to that of a performance supercar. The smell, and when the vehicle speed reaches about 100km/h, the sound of the motor is obviously not that high. What's more important is that the feeling of full power being delivered as soon as the switch is pressed when exiting a corner is indeed very smooth.

The editor lay down on the ground to take a look at this gearbox. The size is actually not much larger than the average single-speed reducer of an electric vehicle, so the installation is not a big problem! And if we calculate the cost, use a smaller motor and battery, and pair it with this gearbox for better power and power saving. After calculating the cost, it may be worthy of the car manufacturer to consider its application.

Of course, some people may doubt whether the CVT gearbox can withstand the high torque of the motor, but according to Cai Zhijian, technical director of Bosch (Shanghai), the steel belt of the CVT4EV can withstand a torque of 600Nm. I believe it will be suitable for It is sufficient for most electric vehicles.

More fun to drive and more worry-free

A clutch management system also appeared at the event. To put it bluntly, this thing is a mechanism for automating the clutch of a manual transmission car. As early as Renault's Twingo was already in use in the 1990s, so what's so special about Bosch's system?

What’s special about it is that it is highly integrated with the vehicle power system. It can appropriately control the engine speed according to the driver’s different shifting actions, and can also remind the driver to shift gears according to a certain energy consumption and economy. action.

In addition, in the past, as long as the driver's hand on the gear lever was placed on the Twingo, the shift pressure sensor would judge and control the half-clutch. The problem of the clutch plate being easily burned is no longer the problem. Bosch's clutch management system can Through a logic program, it is determined whether the driver's hand is habitually placed on the gear lever or whether he really has the intention to shift gears.

The trial car is the Wuling Hongguang S, known as the "sacred car on mountain roads". Since there is no clutch pedal, the feeling of driving this car becomes more smooth and relaxed, and there is no slippage when starting uphill. Yu.

Furthermore, Bosch's clutch control response is fast and smooth. In addition to the driving feeling, it is perfect for me to use in a stop-and-go environment in the city. Technology does not necessarily have to overthrow the past. Making the original technology more perfect is also an achievement!

In addition, regarding the steering technology of steer-by-wire, the editor specifically asked the on-site technician. He said that there is no hard connection or backup link mechanism between the steering wheel and the steering gear of this system, but There are no problems in terms of safety, because this steer-by-wire system was developed for autonomous driving needs and must pass numerous safety tests before it can be applied.

I saw in the Audi A3 trial car modified with a steering-by-wire system that many computer devices are also placed in the passenger seat, which allows engineers to flexibly adjust the system's working characteristics.

The current steering-by-wire system can already provide a variety of steering mode experiences, from the most comfortable mode, where the steering wheel is turned from the middle position to the left dead center for one and a half turns, to the most sporty mode, where the steering wheel is turned from the middle position to the left dead center for one and a half turns. It reaches the left dead center at 180 degrees, and the difference is huge. It is obvious that the latter is more flexible and easier to use when negotiating some tricky corners.

Moreover, the accuracy of this system's hands-off return is very high, and the texture of road feedback is also handled well. I really hope my car can also be equipped with a steering system like this!

The future of travel & the development potential of commercial vehicles

At the experience day event, the "Focus Observation Room" summit forum was also held. Xu Daquan, Executive Vice President of Bosch China, and many Experts and scholars talked about the possibility of autonomous driving, shared travel, and even ground-air collaborative travel, proposing many possibilities for people's future travel technology.

In addition, some people may think that the epidemic has had a great impact on the passenger vehicle market, but absolutely no one objects to the rapid growth of the commercial vehicle market during this period. After all, it transports various medical and daily supplies. All have to use commercial vehicles. The fifth-generation millimeter-wave radar, third-generation camera, and commercial vehicle Servotwin electro-hydraulic power steering system launched by Bosch for commercial vehicles were also present at the event. In addition to achieving currently achievable ADAS functions, it is also foreseen that commercial vehicle automation The future of driving.

This article comes from the author of Autohome Chejiahao and does not represent the views and positions of Autohome.