Anti-lock braking (AB) systems are designed to maintain driver control and car stability during emergency braking. Locked wheels will slow a car but will not provide steering ability. ABS allows you to apply maximum braking while retaining the ability to "get out of trouble." The theory behind anti-lock brakes is simple. A wheel that skids (where the contact patch of the tire slides relative to the road) has less traction than a wheel that does not skid. By preventing the wheels from skidding while you slow down, anti-lock brakes benefit you in two ways: you'll stop faster and you'll be able to steer while you stop. An ABS system monitors all four wheel speed sensors to assess wheel slip. Slip can be determined by calculating the ratio of wheel speed to vehicle speed, which is calculated continuously from the four individual wheel speeds. When braking, the function of the control system is to maintain maximum possible grip of the wheels on the road - without locking the wheels - by adjusting the hydraulic fluid pressure of each brake by means of electronically controlled solenoid valves. Say no to plagiarism. Get a tailor-made essay on “Why Violent Video Games Should Not Be Banned”? Get the original essay Automakers around the world are competing with each other to imagine more reliable machines, moving closer to the fantasy of the "propelled wellness vehicle" or the "extreme vehicle." safety vehicle”, on which innovative work has been ongoing for several years now. Most newer vehicle models offer ABS as standard or optional equipment. Locking the wheels during braking causes slipping, which therefore leads to a loss of stability and control of the vehicle. This diminishes the control's ability to change course. So the car is sliding wildly. In any case, the wheel that is still rotating can be steered. This is what ABS is all about. With such a frame, the driver can brake sharply, make an underhand movement and remain responsible for the vehicle in any road condition, at any speed and under any heap. ABS does not reduce intermittent separation, but rather compensates for changing position or stacking of tires by preventing wheel lockup. During anti-freeze braking, when the wheels are about to lock, the sensors detect that the wheel has recently started to turn more slowly than the other wheels of the vehicle. They therefore quickly reduce the braking power on the influenced wheel. This anticipates wheel slippage on the asphalt. The moment the wheel starts moving again, full braking power is connected again. The ABS repeats the procedure until there is never a need for balanced braking again. ABS acts faster than any driver, pumping the brakes several times per second. Depending on the type of system, ABS modifies the braking power of each wheel or set of wheels, although the driver's foot on the brake pedal operates each of the brakes without a moment's delay during typical braking. The theory behind anti-lock brakes is this: simple. A wheel that is spinning (where the contact patch of the tire is sliding relative to the road) has less traction than a wheel that is not slipping. If the vehicle is stuck on ice and the wheels are spinning, the vehicle has no traction. In fact, the contact zone slides relative to the ice. By preventing the wheels from skidding while you slow down, anti-lock brakes benefit youin two ways: you'll stop faster and you'll be able to steer while you stop. Good drivers have always applied the brake pedal during emergency stops to avoid wheel lockup and loss of steering control. ABS simply does the pumping job much faster and in a much more precise manner than the fastest human foot. The brakes on a non-ABS vehicle lock the wheels very quickly when the driver suddenly applies the brake. In this situation, the vehicle slides instead of stopping. The slippage and lack of control was caused by the wheels locking. Releasing and reapplying the brake pedal will prevent the wheels from locking up which will prevent skidding. An electronically monitored slowing down mechanism does just that. When the brake pedal is pumped or pulsed, pressure is quickly applied and released at the wheels. This is called pressure modulation. Pressure modulation prevents wheel locking. ABS can modulate brake pressure up to 15 times per second. By modulating the brake pressure, friction between the tires and the road is maintained and the vehicle can stop in a controllable manner. Steering is another important consideration. As long as a tire doesn't slip, it only goes in the direction it's turned. But once it skids, it has little to no directional stability. Vehicle maneuverability is reduced if the front wheels are blocked and vehicle stability is reduced if the rear wheels are blocked. ABS precisely controls the rate of wheel slip to ensure maximum grip force of the tire and thus ensures vehicle handling and stability. Many different ABS are found on today's vehicles. These designs vary in their basic layout, operation, and components. ABS components can be divided into two categories. Hydraulic ComponentsElectrical/Electronic ComponentsIn addition to these normal and conventional brake parts, they are part of the overall brake system. Accumulator: An accumulator is used to store hydraulic fluid to maintain high pressure in the brake system and provide residual pressure for power braking. Normally, the accumulator is charged with nitrogen gas and is an integral part of the modulator unit. Anti-Lock Hydraulic Control Valve Assembly: This assembly controls the release and application of brake system pressure to the wheel brake assemblies. It can be of integral type and of non-integral type. In integral type, the unit is combined with the power increase unit and master cylinder into one assembly. The non-integrated type is mounted outside the master cylinder/power booster unit and is located between the master cylinder and wheel brake assembly. Both types typically contain a solenoid valve that controls the release, maintenance, and application of brake system pressure. Booster pump: The booster pump is an assembly of an electric motor and a pump. The booster pump is used to supply ABS hydraulic fluid under pressure. The pump motor is controlled by the system control unit. Booster/Master Cylinder Assembly: This is called a hydraulic unit, contains the valves and pistons necessary to modulate the hydraulic pressure in the wheel circuit during ABS operations. Fluid accumulator: different from a pressure accumulator, a fluid accumulator, temporarily stores brake fluid, which is removed from the wheel brake unit during the ABS cycle. This fluid is thenused by the pump to create pressure for the hydraulic braking system. Hydraulic control unit: This assembly contains a solenoid valve, fluid accumulator, pump and electric motor. The unit may have one pump and one motor or it may have one motor and two pumps. Main Valve: This is a two position valve and is also controlled by the ABS control module and is open only in the ABS model. When open, pressurized brake fluid from the booster circuit is directed to the main circuit to prevent excessive pedal travel. Modulator Unit: The modulator unit controls the flow of pressurized brake fluid to the individual wheel circuits. Normally, the modulator is made up of the solenoid that opens and closes the valves, several valves that control the flow of fluid to the wheel brake units, and electrical relays that turn the solenoids on or off via commands from the control module. This unit may also be called a hydraulic actuator, hydraulic unit or electro-hydraulic control valve. Solenoid Valves: Solenoid valves are located in the modulator unit and are electrically actuated by signals from the control module. The control module activates or deactivates solenoids to increase, decrease or maintain hydraulic pressure on the various wheel units. Wheel Circuit Valves: Two solenoid valves are used to control each circuit or channel. One controls the circuit inlet valve, the other controls the outlet valve. The position is determined by the control module. The outlet valves are normally closed and the inlet valves are normally open. The valves are activated when the ABS control module switches 12 volts to the circuit solenoids. During normal driving, the circuits are not activated. ABS Control Module: This small computer is normally mounted inside the trunk on the wheel well, mounted on the master cylinder, or is part of the hydraulic control unit. It monitors the operation of the system and controls the anti-lock function if necessary. The module relies on input from the wheel speed sensors and feedback from the hydraulic unit to determine whether the ABS is operating properly and to determine when anti-lock mode is required. Brake Pedal Sensor: The anti-lock brake pedal sensor switch is normally closed. When the brake pedal exceeds the anti-lock brake pedal sensor switch setting during an anti-lock stop, the anti-lock brake control module detects that the anti-lock brake pedal sensor switch is open and grounds the anti-lock brake pedal sensor switch. pump motor relay coil. This activates the relay and turns on the pump motor. When the pump motor is running, the hydraulic reservoir is filled with high pressure brake fluid, and the brake pedal is pushed up until the anti-lock brake pedal sensor switch closes. When the anti-lock brake pedal sensor switch closes, the pump motor is turned off and the brake pedal will move down a little with each ABS control cycle until the anti-lock brake pedal sensor switch opens and the pump motor is restarted. This minimizes pedal feedback during the abs. cycling.Differential pressure switch: It is located in the modulator unit. This switch sends a signal to the control module whenever there is an unwanted difference in hydraulic pressures in the brake system. Relays: Relays are electromagnetic devices used to control a high current circuit with a low current switching circuit. In abs, relays are used toswitch motors and solenoids. A low current signal from the control module powers the relays that complete the electrical circuit of the motor or solenoid. It can be located on an axle shaft, a differential or the hub of a wheel. This ring is used in conjunction with the wheel speed sensor. The ring has a number of teeth around its circumference. As the ring rotates and each tooth passes the wheel speed sensor, an alternating voltage signal is generated between the sensor and the tooth. It is mounted near the different toothed rings. As the teeth of the ring rotate in front of the sensor, an alternating voltage is generated. As the teeth move away from the sensor, the signal is interrupted until the next tooth moves closer to the sensor. The end result is a pulsed signal that is sent to the control module. The control module translates the signal into wheel speed. The sensor is normally a small spool of wire with a permanent magnet at its center. One of the classifications of abs is integral and non-integral type. The integral type combines the master cylinder, hydraulic booster and hydraulic circuit into a single hydraulic assembly. In the non-integral type, they use a conventional vacuum booster and master cylinder. Additionally, they can be classified based on the control they provide. This is the best scheme. There is a speed sensor on all four wheels and a separate valve for all four wheels. With this setup, the controller monitors each wheel individually to ensure it achieves maximum braking force. This system commonly found on pickup trucks with four-wheel ABS, has a speed sensor and valve for each of the front wheels, with a valve and sensor for the two rear wheels. The rear wheel speed sensor is located in the rear axle. This system provides individual control of the wheels, so that they can both achieve maximum braking force. The rear wheels, however, are monitored together, they must both begin to lock before the ABS activates at the rear. With this system, it is possible for one of the rear wheels to lock when stopping, thus reducing the effectiveness of the brakes. This system is commonly used on pickup trucks equipped with rear wheel ABS. It has one valve that controls the two rear wheels and another. -speed sensor, located in the rear axle. This system works the same as the rear end of the rear channel system. The rear wheels are monitored together and both must begin to lock before the ABS intervenes. In this system, it is also possible that one of the rear wheels locks, reducing the effectiveness of the brakes. Advances in ABS Some systems, which work with ABS, are automatic traction control and automatic stability control, which are discussed below. Automatic Traction Control (ATC) Automatic traction control systems apply the brakes when a driven wheel attempts to slip and lose traction. The system works best when one drive wheel is working on a good traction surface and the other is not. The system also works well when the vehicle accelerates on slippery surfaces, especially when going up hills. ATC is particularly useful on four-wheel drive or all-wheel drive vehicles in which loss of traction on one wheel could interfere with driver control. During on-road operation, the ATC system uses an electronic control module to monitor the wheel speed sensors. If a wheel loses traction, the module.