What is ABS, BAS, ESP, EBD, IVD, etc.?
The first developments of ABS date back to the thirties of the last century, but serial equipment of cars began only in the mid-seventies. The idea of ABS operation is quite simple. The computer analyzes the signals of the wheel rotation sensors and actuates the brakes. as if imitating the actions of an experienced driver during intermittent braking, not allowing the wheels to be blocked. Since the advent of ABS, there have been debates between experts and amateurs about the usefulness of the system. Its most useful qualities are reducing braking distance and maintaining control of the vehicle during emergency braking. The disadvantage – it is difficult to calculate the braking distance. The argument, what to say, is weighty. However it is better to stop in ignorance a few meters up to an obstacle, than to bump into it with precisely calculated braking distance. Till some time we agreed that the system will be useful for a beginner, but an experienced driver can “outplay” ABS. But the development of electronics has led to the fact that in the “skilled driver – ABS” fight the latter has won a convincing victory. Modern multichannel ABS completely outplay even a professional driver. Even such unpleasant thing as vibration of a brake pedal was eliminated. There were cases when the accident happened due to its too sharp actuation. When the brake pedal began to vibrate and the car began to make strange noises, inexperienced drivers were frightened and released the pedal… Therefore, in the most modern braking systems the driver hardly feels the activation of ABS. Now, the anti-lock braking system is standard on almost all cars, and it is often backed up by more sophisticated electronic safety systems.
ASR (TRC (traction control), STC, TRACS, ASC+T)
The first logical development of ABS was the ANTIBROCK system. The principle of operation is simple: at the moment of moving off the car, the sensors (ABS) fix the slip of one of the leading wheels, and the computer brakes it with the help of brakes. If necessary, the same electronics can reset the engine revolutions, since there is no mechanical connection between the “gas” pedal and the throttle in modern cars. That is, if you “sink” the pedal to the floor, the computer will not let the leading wheels to burn rubber and grind asphalt or ice in vain, but accelerate the car as quickly as possible, without slipping. The anti-skid system will not prevent any car, irrespective of type of a drive. The real treasure is ASR for SUVs. Instead of complicated transmissions they use all-wheel drive with free differentials, and the role of blocking is assigned to electronics. This scheme is not suitable for impassable lack of roads, but it will be just right for “parkettes”. Certainly, ASR has its disadvantages. For example, such system will disturb an experienced driver while trying to pull out stuck automobile “on the sway” by inappropriate braking and dropping “gas”. Moreover, it can suffocate the engine and wheels so much, that the car will not be able to move at all. ASR interferes with the skidding of the car for active drivers, controlling its traction. On the other hand, the anti-skid system successfully performs the function of differential lock, slowing down the unloaded wheel in the turn and thus balancing the speed of the wheels, and allows the most efficient use of engine torque. Not all automconsultants indulge whims of buyers, and therefore make the system not switch off. But it is “at them” that it is not switched off. Our fellows, not even studying the electric scheme, solve a problem simply by removal of a fuse. However, we do not advise to do it. If you stubbornly consider that ASR interferes with realization of racer’s talent, we remind you that this system is used in Formula 1.
Further development of ABS led to the appearance of modern cars of the system of electronic brake force distribution. These systems always work in tandem, so most often in catalogs you can see the abbreviation ABS+EBD. The idea of EBD grew out of the fact that when braking sharply on uneven pavement, the car begins to turn around. This is due to the fact that the degree of traction of the wheels on the road is different, but the braking force transmitted to the wheels is the same. The EBD system, using ABS sensors, analyzes the position of each wheel during braking and strictly individually doses the braking force on it. This takes into account the load on the vehicle and its position relative to the road surface. The benefit of EBD is especially noticeable when braking in a turn. I think many of our drivers have repeatedly demonstrated a “high” level of speech culture and subconscious knowledge of profanity, when in a closed corner in front of them was the car of another “smart guy”, who thought to rest on the curb. Exactly EBD allows braking in such situation, without losing control over the car. Without this system, braking will end at the best case with drifting off the trajectory. I am sure, there will be no disputes concerning EBD usefulness.
Brake assistant (brake assist, BAS)
Another assistant, which appeared as a result of the “struggle” for safety, is called the brake assistant. Its purpose is to reduce the maximum possible braking distance of the car during emergency braking. How the system achieves this? A special sensor analyzes the movement of the brake pedal and the force of pressure on it at the moment of braking. “Coming to the conclusion” that the driver is trying to brake in an emergency, or, in other words, in a panic, hit the brake pedal, brake assistant for a few milliseconds increases the pressure in the brake line. In this case the braking time is significantly reduced, and this means winning meters of braking distance. It is only worth adding that the system recognizes really panic actions of the driver, or if he presses on the brake pedal for a long time. Even at rather sharp, but “predictable” braking BAS does not come into operation. First of all, this system is addressed to the weaker sex. Often, women just do not have enough strength for emergency braking, and at the right moment, the BAS helps them, “pressing” the pedal for maximum deceleration.
ESP (VDC, VSC, DSTC, DSC, ATTS, VSA, Stabilitrac)
Do you remember the sensational story about the overturning of the Mercedes-Benz A-Class? If not, let me remind you. In 1997, during a driving presentation, the car overturned during a “rollover” maneuver. After a flood of criticism that hit the concern, the Mercedes management announced to the whole world that all A-Class cars would be equipped with the company’s Dynamic Stability System free of charge. It was the use of electronics allowed to finally solve the problems with handling. Prior to that, ESP was custom installed on S-Class cars back in 1995. ESP today is the highest level of evolution of electronic active safety systems, combining the best solutions of the above mentioned. The ESP principle is based on the ability to control the car’s drifting and oversteering not only by steering and throttle but also by braking one or more wheels. If the car is drifting with the front axle, the system brakes the inside of the rear wheel in relation to the turn, giving the car oversteer. When a skid is threatened, the outer front wheel is braked. When all four wheels drift, ESP calculates which wheel to brake and when to brake. Together with braking the system “resets” the engine speed. Thus, using ABS and ASR actuators, the system is able to brake each wheel separately. But only ABS sensors are not enough for ESP to do such a complicated job. That’s why additional sensors are installed in the car. One tells the system which way and at what speed the steering wheel is turning. Two more “complain” about the angle of car’s turn and the level of lateral acceleration. The readings of this company of sensors allow you to instantly calculate what is going on with the car, and actuate the actuating mechanisms. Naturally, it is not without disadvantages, if they can be called such. One can complain, for example, that the system will interfere the experienced driver, who calculates each his motion a few steps ahead. But ESP doesn’t predict the future, but corrects made mistakes. Therefore, it will not let to pass a turn in a controlled drift, having interfered at the most inappropriate moment. But in all other cases, ESP will render really invaluable help, not only to the beginner driver. In the end, I want to pay your attention once more to the fact, that only active drivers complain about the work of the listed systems. But remember, the purpose of electronic assistants is active SAFETY, not active driving. And then everything at once falls into its places. And lastly, it has been already said more than once: no electronics are able to overcome laws of physics.
What is BAS in a car and what is it for?
BAS is considered an additional system, which has different names from car manufacturer to car manufacturer. BAS stands for Brake Assist System. In some brands, it may be called EBS or EBA. The system is very useful in using the car, as it triggers when the brakes are urgent.
The useful invention contributes to quick and hard braking. Basically, this system automatically starts applying pressure to the hydro-pneumatic brake to the highest possible force. This additional system helps to reduce accidents on the road or reduce the damage from the resulting accident.
How the BAS works
The automatic system works well and quickly. It identifies in a short time the moment when the pedal is pressed too sharply than in other situations. In this case the pedal is pressed with insufficient force, but very sharply. If the system detects braking with a high degree of danger, it triggers emergency braking.
It is possible to install such a system on modern vehicles of any make and model, where ABS auto system will also be installed. The main mistake all drivers make is incorrectly responding to the urgent situation. Most drivers do not press the brake pedal correctly, as required in reality. Some drivers don’t apply the brake pedal hard enough, while others apply it slowly.
In both cases, the system cannot recognize this signal and does not activate the BAS. These two problems cause the highest pressure level to be reached slowly, while it should be as fast as possible. As a result, the braking distance increases, while it could have been much shorter with the right amount of force.
The positives of emergency braking
The BAS system is good because it is able to recognize the driver’s actions and analyze them. The system analyzes driver behavior. It increases the pressure level in the system. Together with the ABS anti-lock braking system, this system works very well. That’s why BAS and ABS are paired in any case, and it helps to brake in an emergency.
If the rate of pressure increase is too high, however, the system will also not respond correctly to such action. The signal unit will understand that the driver wants to use emergency braking. As a result, the module starts the automatic electric pump, and it itself contributes to increasing the pressure in the braking system to the highest pressure. The pump will run until the driver takes his foot off the pedal.
If the car has accelerated to the highest speed and the brake has been quickly applied, the system begins to work at full force. In this case, the ABS system is not blocked. BAS is able to work in a short time. It only needs a few fractions of a second to fully analyze it.
In a mechanical system, emergency braking must be properly defined. This requires setting a boundary and defining a threshold value. The braking analysis of the automatic system is determined by the ratio of the brake pedal speed to the brake pedal force and force. In each vehicle, the threshold can be determined individually.
The emergency braking system was developed by Mercedes-Benz. This firm paid special attention to safety on the roads. After a series of tests, it was able to prove to everyone that BAS should be installed in every car. The system enables the braking distance to be shortened by up to 45 percent in the event of emergency emergency emergency braking. For every driver on the road, safety is everything. That is why every vehicle must have Brake Assist.