In this issue
As the most basic performance of vehicle handling and safety, the braking performance of automobiles has received widespread attention.
However, before the level of braking performance, everyone only stayed on the judgment of the braking distance (0-100km/h braking distance at speed), or the hard or soft on the "foot feeling", which is difficult to fully and completely reflect the impact of a car's braking performance on the driving quality. Not to mention the concept of braking comfort, which may be unfamiliar to many people, and there have not been many studies and evaluations for this purpose, but its impact on the quality of the vehicle is very direct (refer to the memory of previous bus rides).
In order to study and improve the braking performance of the car more comprehensively and meticulously, the driving evaluation in the group standard of the "Automobile Driving Experience Test and Evaluation Regulations" (hereinafter referred to as the group standard) released a few days ago, around the brake performance consideration standard to develop a more subdivided, more comprehensive consideration of the consumer driving experience of the research evaluation system, which mainly includes brake safety and brake comfort two major test evaluation parts, popular understanding is the brake performance level of "not OK" and "good or bad" evaluation, today we talk about braking comfort.
In the brake comfort evaluation system of the group standard, around the brake comfort that can reflect the subjective experience of consumers, normative evaluation standards and methods have been formulated, which are mainly divided into two dimensions: [brake pedal sense] and [brake pitch], of which the four-level indicators of [brake pedal sense] are pedal force, pedal stroke and linear sense; the four-level indicators of [brake pitch] are brake pitch size, brake pitch convergence and brake pitch abruptness.
Specifically, the brake pedal force evaluates the operating sensation of the brake pedal when braking, and the evaluation is carried out in a subjective evaluation method, which is similar to the "foot feeling" that the user and the media subjectively feel during the test drive. The method is to recommend a speed of 0~120km/h, drive the vehicle at different initial speeds at a uniform straight line, and continuously and gradually step down the brake pedal after the vehicle is stabilized, until the brake pedal is stepped on to the end and the vehicle is in a stopped state.
Brake pedal stroke evaluation of the total stroke and free stroke size of the brake pedal, popularly speaking, mainly includes whether the brake pedal stroke is too long or too short, whether there is a vacancy (how much to step on) and so on.
The linearity of braking comprehensively evaluates the relationship between pedal stroke, deceleration and pedal force when braking, such as the linearity of this relationship and the size of the established gradient. That is, the degree of matching and perfecting of the pedal force applied by the driver, the stroke and the actual deceleration performance of the vehicle, and the impact on the driving quality experience.
The size of the brake pitch, the convergence of the brake pitch and the abruptness of the brake pitch focus on the degree of convergence and pitch shaking of the body after the brake stop is evaluated.
In short, these evaluation methods and standards can examine and reflect the vehicle's braking comfort performance level in a more detailed and comprehensive manner. Cars with poor evaluation of braking comfort are either too soft and space-like for the brakes, and the driver has no confidence; or the foot feeling is too heavy, the braking force release is too abrupt, and the driver's expectations do not match, and even obviously feel the body is frustrated, shaken, shaken, and abnormal, which greatly affects the driving experience. In turn, the vehicles that perform well in our braking comfort evaluation must be linear and natural in braking efficiency, and the driver's operation is reasonable, relaxed and calm, which has less impact on the smooth driving and stopping of the body.
In addition, the dust, smoke, odor, etc. of the braking system also belong to the category of braking comfort, but these situations belong more to the basic qualification of the hardware, and we mainly conduct dynamic evaluation from the perspective of driving experience. It should be emphasized that today's pure electric vehicles have become a major trend in the automotive industry, as we all know because of the physical characteristics, the kinetic energy release and acceleration performance of electric vehicles far exceed that of traditional fuel vehicles, so in this case, we should pay more attention to the braking performance of the vehicle, of course, including braking comfort, not only "braking", but also "braking steadily". The evaluation rules proposed by the driving evaluation in the group standard for the formulation of comfort are introduced after in-depth research in a technical segment that has been neglected by the industry before, so as to promote the more detailed and comprehensive improvement of the driving quality of automotive products.
(The above pictures come from the Internet, invaded and deleted)
Content Consultant for this issue
Expert Opinion | PROFILE
Zhang Huijian
Changan Ford vehicle dynamic attribute expert Automotive driving evaluation alliance expert
We hear that the brake is hard or the brake is soft, in fact, the owner is describing the sense of pedal; the sense of pedal is mainly determined by the brake system, the traditional brake system is a vacuum assist braking system, the adjustment is mainly to adjust the hardware, the late optimization is difficult, the cycle is long; with the promotion of new energy and intelligence, the electronic assisted braking system (EBB) is more and more widely used, EBB can adjust the size of the pedal force, pedal stroke and deceleration through software, which makes the adjustment of the brake pedal sense more precise, And it can be adapted to different driving modes, making the braking of the comfort mode more relaxed and free, making the braking of the sport mode more aggressive and more enjoyable.