Why is the probability of brake failure higher in electric vehicles than in fuel vehicles?
Doesn't Tesla claim to be the most technologically advanced, why can't it handle the brake problem? Were the brakes malfunctioning because of poor driving skills of people using Tesla cars?
The automobile industry has a history of more than one hundred years, and the braking technology has been quite mature. Traditional automobile brands and even some new domestic electric vehicle brands rarely have braking problems, while Tesla has a lot of braking incidents, and the proportion of braking problems is much higher than other brands.
The vast majority of fuel vehicles are vacuum boosters. Tesla uses Bosch's iBooster, which is an electronic-controlled component that can fail and misdiagnose software.
The vacuum booster uses the engine intake manifold of the fuel vehicle to provide vacuum, and uses the atmospheric pressure and the pressure difference of the vacuum to help. As long as the engine works, the vacuum source always exists. Vacuum booster is also pure mechanical parts, the probability of failure is very low.
In new energy vehicles, there is no vacuum source. The old scheme is to add electronic vacuum pump, vacuum tank and other parts. The vacuum pumped by the electronic vacuum pump is stored in the vacuum tank. When the vacuum of the vacuum tank is low, the vacuum pump works to ensure the vacuum degree. The disadvantage of this system is that it has too many parts.
The iBooster is used in new energy vehicles to improve the energy recovery efficiency of the vehicle on the one hand (the iBooster uses ESP-HEV to decouple the braking system), and on the other hand, it can meet the requirements of unmanned driving (active braking function, while traditional vacuum booster does not have active braking function). Too long response time using ESC active build pressure)
The iBooster uses a low-voltage motor controller to drive the motor. As long as the electronic components are involved in the booster, there is a probability of failure. In other words, Tesla says that brake failure is a normal low-probability event. In order to detect whether the electronic components are normal and whether the function can be realized, the corresponding software diagnosis function needs to be developed. When the fault is diagnosed, the safety policy will be entered, such as turning off the motor output.
According to reports from Tesla users, Tesla sometimes has no braking power when the first foot is pressed (that is, people on the Internet say the brakes are hard), but when the pedal is released, the power comes back again. According to this analysis, the probability of misdiagnosis is higher (because the electronic components used in the car are required to be of car grade and meet the AECQ standard, and the probability of failure is very low).Even if the accident vehicle is pulled to the quality inspection center for quality inspection, it may not be able to repeat the false diagnosis. That is to say, the reinspection proposed by Tesla is actually not convincing.
The iBooster is one of the future brake systems that could be used on a large scale like the EPS.
What Tesla should do is to work with Bosch to find out the cause of the problem, fundamentally solve the problem and improve the reliability of the system.