Produced by | Sohu Auto New Car
Recently, there are a lot of videos about Xiaomi SU7 going down the track "on the wall", in addition to the size of the brake pads, the most discussed thing is actually the brake-by-wire system that many new cars are equipped with. So, what exactly is brake-by-wire? What is the difference between it and traditional hydraulic brakes? What are the advantages and disadvantages? Let's answer them one by one.
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First of all, what is brake-by-wire technology?
To put it simply, brake-by-wire is actually when you take a controller to play a racing game, and the brake pedal is just a deceleration button. It controls the brake actuator by electronic signals to achieve the braking function, eliminating the complex hydraulic lines in the traditional braking system. Compared with traditional braking, this system can realize the decoupling of foot feel, that is, the braking force and pedal feedback force can be defined. In addition, in terms of system characteristics, it has high construction pressure, large output, and strong redundancy functions. Therefore, in order to take into account both performance and intelligent driving, many new energy vehicles now adopt decoupled electronically controlled braking systems.
What are the advantages and disadvantages of brake-by-wire?
First of all, because it is an electrical signal, it has three advantages: fast response speed and accurate control, which are more suitable for high-end intelligent driving; Hydraulic system lines are eliminated, maintenance costs are lower, and there is no need to worry about brake fluid deterioration. There are also disadvantages, such as the decoupling of the pedal and brake, although the foot feel can be consistent, but in extreme situations such as going off the track, the brakes are attenuated, or overheated, or the disc is worn out.
We still need the system to make certain adjustments to the brake feel, such as through the brake pedal force change or other ways to alert the driver. In the face of these problems, in fact, there are some models on the market that have prompted brake attenuation, such as actively shortening the pedal travel, reducing the output power of the motor, or forcing kinetic energy recovery.
So the brake-by-wire scheme is only suitable for family cars?
Of course not, on the contrary, the brake-by-wire scheme is more favored by races, such as F1, which uses the brake-by-wire scheme provided by Brembo. The solution, called Brake-by-Wire, uses an innovative "decentralized" architecture that eliminates the brake master cylinder and allows each wheel to have its own electric brake actuator. When the driver presses the brake pedal, the pedal sensor detects the change in force and transmits the signal to the front and rear BCUs (brake control units). The BCU then sends signals to the front and rear actuators to establish the braking force. In this way, each wheel can be controlled independently, further improving the reaction speed and control accuracy.