Auto InfO

What is EBD?
When a rotating wheel is subjected to excessive heavy braking, it is prone to lock-up. In motor vehicles,
the anti-lock braking system (ABS) works to prevent this by monitoring wheel speeds and taking action in the form of releasing pressure on the braking circuit, when a rapid deceleration occurs in any of the wheels to ensure steering and vehicular control is maintained during heavy or emergency braking. This has its disadvantages though, as different amounts of braking pressure are required to lock a rotating wheel on different surfaces.

EBD Operation

How does it works?
here is an example to explain how EBD work, less braking pressure would be needed to lock a wheel which was in contact with ice than a wheel which was in contact with an asphalt road.

 In a situation where the wheels of a vehicle are on different surfaces (for example the two left wheels are on a concrete road and the two right wheels were on snow), during an emergency stop ABS would detect the two right wheels about to lock and would activate, even though the two left wheels would not have locked when the right wheels did.

 EBD detects such conditions and electronically controls the braking force applied to each individual wheel, and therefore maximizes the braking force to ensure a maximum braking effectiveness. The final result is more precise and effective braking under all conditions, and also makes the car much more stable under heavy braking, reducing front end dive

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What is ESC or ESP?
 Electronic Stability Control (ESC) is a computerized system designed to improve a vehicle's handling by detecting and preventing skids, helping the driver maintain control of the vehicle.

Note: (ESP always needs ABS system, where the ABS plays as an Actuator while the ESC playing as the controller) . Read about ABS
 ESC simplifies steering for the driver. ESC uses the vehicle's braking system as a tool for "steering" the vehicle back on track. Braking is automatically applied to individual wheels, such as the inner rear wheel to counter under steer, or the outer front wheel to counter over steer. Some ESC systems also intervene by reducing engine power or accelerating the driven wheels.

ESC components

One step beyond ABS is modern ESC systems. Here, two more sensors are added to help the system work. These are a steering wheel angle sensor, and a gyroscopic sensor.

The theory of operation is simple: when the gyroscopic sensor detects that the direction taken by the car doesn't agree with what the steering wheel sensor says, the ESC software will brake the necessary wheel(s) (up to three with the most sophisticated systems) so that the car goes the way the driver intends.

The wheel sensor also helps in the operation, since this will tell the ABS that wheels on the outside of the curve should brake more than wheels on the inside, and by how much.

 How does it work?
ESC compares the driver's intended direction (by measuring steering angle) to the vehicle's actual direction (by measuring lateral acceleration, vehicle rotation (yaw) and individual wheel speeds). If the vehicle is not going where the driver is steering, ESC then brakes individual front or rear wheels and/or reduces excess engine power (not all systems can reduce engine power) as needed to help correct under-steer (plowing) or over-steer (fishtailing).

Effect of ESC by using ABS system

ESC incorporates yaw angle control into anti-lock brakes. Yaw is rotation around the vertical axis; i.e. spinning left or right. Anti-lock brakes enable ESC to brake individual wheels.

ESC may also incorporate traction control, which senses drive-wheel slip under acceleration and individually brakes the slipping wheel or wheels and/or reduces excess engine power until control is regained.
ESC cannot override a car's physical limits or increase traction. If a driver pushes the vehicle's traction beyond its limits, ESC cannot prevent a crash. It is a tool to help the driver maintain control using available traction.


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There is an old story about a man who was run in front of the old cars to warn people (Danger coming after me).  That is why we need brakes, to not run over this Guy :)
But you will be in a big problem when the brake Stuck with the wheels due to friction overheat, or when your car tires become friction-less with the road, in other words goes over Oil or Ice.

Once the wheel has stopped (stuck) its becomes as fixed-point or hinge and this car will rotate around this point or your car skids so you can not steer your car to the correct direction, thus (Bang) because of unexpected behavior!!!!!!!! 

Some years later. The German firms (Bosch and Mercedes-Benz) had been co-developing anti-lock braking technology, and introduced the first completely electronic 4-wheel multi-channel ABS system in trucks and the Mercedes-Benz S-Class in 1978.



What is ABS?
An anti-lock braking system (ABS) is a system on motor vehicles which prevents the wheels from locking while braking. An anti-locking braking system allows the driver to maintain steering control under heavy braking by preventing a skid and allowing the wheel to continue to forward roll and create lateral control, as directed by driver steering inputs in case of extreme braking circumstances.
 
This is achieved by controlling the rotational speed of every wheel and metering the brake line pressure at the time of skid braking.

Research has shown that  anti-lock brake system can decrease the chance of a vehicle accident by 18%.

ABS System

ABS System parts:

How does it work?

A typical ABS is composed of a central electronic unit, four speed sensors (one for each wheel), and two or more hydraulic valves on the brake circuit. The electronic unit constantly monitors the rotation speed of each wheel.
 When it senses that any numbers of wheels are rotating considerably slower than the others (a condition that will bring it to lock) it moves the valves to decrease the pressure on the braking circuit, effectively reducing the braking force on that wheel.
The wheel(s) then turn faster and when they turn too fast, the force is reapplied.

ABS

This process is repeated continuously, and this causes the characteristic Pulsing feel through the brake pedal. A typical anti-lock system can apply and release braking pressure up to 20 times a second. The sensors can become contaminated with metallic dust and fail to detect wheel slip; this is not always picked up by the internal ABS controller diagnostic.

Most commonly, braking distances are shortened (again, by allowing the driver to press the brake fully without skidding or loss of control). Disadvantages of the system include increased braking distances under rather rare circumstances and the creation of a "false sense of security" among drivers who do not understand the operation and limitations of ABS.   



Press to Watch Brake System Video 1

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