In this article, we will learn about what is anti lock braking system? Its diagram, parts, working, types, advantages, and disadvantages explained with Images.
what is anti locking Braking system ?
The anti lock braking system is a safety anti-skid braking system system used on aircraft and on land vehicles, such as cars, motorcycles, trucks, and buses which prevents the wheels from locking when the brakes are applied.
Note: It is also known as ABS.
In vehicles without ABS, when a driver applies the brakes, the wheels can lock, causing the vehicle to skid on the road. This lack of control can be dangerous, especially when faced with sudden obstacles. However, with ABS, if a driver encounters a large obstacle, they can press the brake pedal without the wheels locking up. ABS prevents the wheels from continuously locking, allowing the driver to maintain control of the vehicle. This means the driver can reduce the vehicle’s speed and even change its direction if needed. In simple terms, ABS helps prevent the wheels from locking, enabling the vehicle to stop without skidding. This improves safety and gives the driver more control in critical situations.
The Anti Lock Braking System (ABS) is a crucial safety innovation in vehicles that prevents the wheels from locking up during braking. By modulating brake pressure to each wheel, the ABS enables drivers to maintain control and steer the vehicle, even in emergency situations. This advanced system significantly enhances vehicle safety and reduces the risk of accidents by ensuring optimal braking performance and stability.
history of Anti Lock Braking System
The history of the Anti Lock Braking System (ABS) stretches back to the early 20th century, with various pioneers and engineers contributing to its development. In 1908, J.E. Francis introduced the ‘Slip Prevention Regulator for Rail Vehicles,’ which can be seen as a precursor to ABS systems. Gabriel Voisin, a French automobile and aircraft pioneer, experimented with hydraulic systems in the 1920s to modulate braking pressure and reduce tire slippage in aircraft.
However, it was not until 1928 that the ABS system gained proper recognition with the German engineer Karl Wässel, who patented a system for modulating braking power. Despite Wässel and later Robert Bosch producing patents, neither of them developed a working product at the time.
In the 1930s, a similar braking system called Decelostat, which used direct-current generators to measure wheel slippage, was employed in railroads. By 1951, Decelostat was being used in aircraft for anti-skid purposes during landings. The Dunlop Maxaret anti-skid system was also introduced in the early 1950s and found widespread use in aviation, improving braking performance in icy or wet conditions and increasing tire life.
In 1958, the Road Research Laboratory tested the Maxaret anti-lock brake on a Royal Enfield Super Meteor motorcycle, demonstrating its potential value in reducing accidents caused by skidding. However, despite the positive results, the system was not put into production by the company.
Limited automobile use of fully-mechanical ABS was seen in the 1960s in vehicles such as the Ferguson P99 racing car, the Jensen FF, and the experimental all-wheel drive Ford Zodiac. These systems, however, proved to be expensive and unreliable, leading to their discontinuation.
The first fully-electronic ABS was developed in the late 1960s for the Concorde aircraft. However, the modern ABS system as we know it today was invented in 1971 by Mario Palazzetti, also known as ‘Mister ABS,’ in the Fiat Research Center. The system, initially called Antiskid, was later sold to Bosch, who named it ABS. Since then, ABS has become a standard feature in almost every car, providing enhanced braking control and safety.
The journey of ABS has been one of continuous innovation and refinement, driven by the goal of improving road safety. Today, ABS has become an indispensable component of modern vehicles, ensuring stability, control, and ultimately, saving lives on the road.
Parts of Anti Lock Braking System
The anti lock braking system (ABS) in vehicles consists of several parts which work together to provide effective braking performance and prevent wheel lock-up.
A speed sensor is which is used for determining the wheel’s acceleration or deceleration. To generate a signal, these sensors employ a magnet and a Hall effect sensor, or a toothed wheel and an electromagnetic coil. A magnetic field is created around the sensor by the spinning of the wheel or differential. The oscillations in this magnetic field cause a voltage to be generated in the sensor. Because the voltage induced in the sensor is caused by the turning wheel, it can become incorrect at low speeds. Slower wheel rotation might generate erroneous fluctuations in the magnetic field, resulting in inaccurate readings to the controller.
Each brake in a car’s ABS system has a valve in its brake line. This valve can be in three different positions:
- In the first position, the valve is open, allowing the pressure from the master cylinder to go directly to the brake.
- In the second position, the valve blocks the line, isolating that brake from the master cylinder. This prevents the pressure from increasing if the driver presses the brake pedal harder.
- In the third position, the valve releases some of the pressure from the brake.
Most problems with the valve system occur when the valves get clogged. When a valve is clogged, it can’t open, close, or change its position. If a valve doesn’t work properly, it prevents the system from adjusting the valves and controlling the pressure that goes to the brakes.
The pump in the ABS system is responsible for bringing the pressure back to the hydraulic brakes after the valves have released it. When the controller detects that a wheel is slipping, it sends a signal to the valve to release some of the pressure. After the valve releases the pressure, the pump kicks in to restore the right amount of pressure to the braking system. The controller manages the pump’s operation to make sure it provides the correct pressure and reduces slipping.
Read: Centrifugal Pump
The controller in the car is like a brain that receives information from each wheel speed sensor. If one of the wheels loses traction, a signal is sent to the controller. The controller then does two things:
- It limits the force applied to the brakes (EBD) so that the wheels don’t lock up.
- It activates the ABS modulator, which controls the braking valves. The modulator quickly turns the braking valves on and off to prevent the wheels from skidding.
Anti Lock Braking System Working
Anti lock braking system (ABS) has four main components: speed sensor, valves, pump, and controller. The speed sensor checks wheel rotation. Valves block or release brake pressure. The pump uses hydraulic fluid to apply pressure to the brakes. The controller, like a brain, uses sensor data to decide whether to pump the brakes.
Wheel sensors monitor each wheel’s speed. If the tires lock up, the controller reads the sensor signals and sends instructions to the valves for that wheel.
The valves quickly apply and release the brakes automatically, preventing tire skidding and helping the driver stay in control. If a wheel slows down significantly, the controller tells that wheel’s valves to reduce brake pressure and close.
The wheels then speed up, and the controller signals the valve to open and increase brake pressure, applying the brakes.
This cycle repeats until braking is normal. So, Anti Lock Braking System works in three stages:
- Brake pedal is pressed.
- Sensors detect skidding.
- ABS pumps the brakes.
Types of Anti Lock Braking System
these are the following types of Anti Lock Braking System;
- Four-channel. Four-sensor ABS
- Three-channel. Four-sensor ABS
- Three-channel, Three-sensor ABS
- Two-channel, Four-sensor ABS
- One-channel, One-sensor ABS
# Four-channel, Four-sensor ABS
Four-Channel, Four-Sensor ABS: This is the most common type of ABS. It uses four wheel speed sensors, one for each wheel, and four separate valves to control brake pressure individually for each wheel. It offers independent control and is highly effective in maintaining stability and control during braking.
# Three-channel. Four-sensor ABS
Three-Channel, Four-Sensor ABS: This type of ABS is commonly found in pickup trucks and SUVs. It uses three wheel speed sensors, one for each front wheel and one for the rear wheels as a pair. The braking force is controlled independently for the front wheels, while the rear wheels share a combined control. It provides good stability during braking.
#Three-channel, Three-sensor ABS
Three-channel, Three-sensor ABS : This type of ABS has separate valves and speed sensors for the front wheels. However, the rear wheels share a valve and speed sensor located in the rear axle. It is commonly used in four-wheel pickup trucks.
The drawback is that both rear wheels must lock up simultaneously for the ABS to activate. If only one rear wheel locks, the ABS may not engage effectively, reducing brake performance. Additionally, the lack of individual speed sensors for the rear wheels makes the system easily identifiable.
# Two-channel, Four-sensor ABS
Two-channel, Four-sensor ABS This ABS system has a speed sensor on each wheel and a control valve for each front and rear wheel as a pair. If the speed sensor detects lockup in any wheel, the control module activates both valves on that end of the vehicle. This type of ABS was commonly found in passenger cars built in the late ’80s and early ’90s.
# One-channel, One-sensor ABS
One-Channel, One-Sensor ABS: One-Channel ABS, as the name implies, has one valve and one speed sensor to monitor all four wheels. It operates similarly to three-channel ABS and is typically installed in the rear axle. However, this type of ABS may allow one of the rear wheels to lock up, leading to reduced brake effectiveness.
You can easily identify this ABS system on a vehicle since it lacks individual speed sensors for each wheel. One-channel ABS is commonly found in pickup trucks, vans, and SUVs, where one valve controls both rear wheels.
anti lock braking system in car means
The term “anti lock braking system” in a car refers to a safety feature designed to prevent the wheels from locking up or skidding during braking. It is a system that helps the driver maintain control of the vehicle while braking, especially in emergency situations. By rapidly modulating the brake pressure to each wheel, the anti-lock braking system allows the driver to steer the car while effectively slowing down or stopping. This helps to improve stability, reduce the risk of accidents, and enhance overall braking performance.
Why Anti Lock Braking System Is Essential In Your Car?
The main purpose of Anti lock braking system in car to prevent skidding caused by locked wheels during hard braking, which can lead to a loss of steering and control. ABS systems are now installed in many new cars to provide extra steering capability in emergency situations rather than solely focusing on reducing stopping distances.
let us understand the requirements of Anti Lock Braking System require in car using a example;
Consider the following example in order to understand the significance of the ABS system in every car. If you are driving down the road and an unforeseen barrier appears in front of you, you must use the brakes fully.
This causes the wheels to lock and your automobile to skid on the road. You lose steering control while skidding and are unable to move the car in the proper direction. You eventually run into the obstruction and have an accident.
Consider another example in which you are driving a vehicle that has an anti-lock braking system. When driving, when you come across an impediment on the road and use the brakes with full force.
This time, your vehicle’s ABS stops the wheel from locking up and skidding. At the same time, you can accurately drive your automobile and avoid hitting the obstacle. As a result, the ABS system keeps the car from slipping, offers more control, and helps to avoid accidents.
anti lock braking system in bike
The anti lock braking system (ABS) in a bike is a safety feature that prevents the wheels from locking up or skidding during braking. It helps riders maintain control and stability while braking, particularly in emergency situations. The ABS system on a bike operates by monitoring the rotational speed of the wheels using sensors. When it detects the possibility of wheel lock-up, it modulates the brake pressure to each wheel.
During normal braking, the ABS allows the rider to apply maximum brake force without worrying about the wheels locking up. If the ABS sensors detect an impending wheel lock-up, the system automatically adjusts the brake pressure by rapidly releasing and reapplying it. This pulsating action prevents the wheels from fully locking up, ensuring they maintain traction with the road surface.
By preventing wheel lock-up, the ABS enables the rider to maintain steering control even under hard braking. This helps to avoid accidents caused by skidding or loss of control. The ABS system in bikes enhances overall safety by providing riders with improved stability and control during braking maneuvers, particularly on slippery or uneven surfaces.
It’s important to note that ABS does not necessarily reduce the stopping distance of a bike, but its primary function is to enhance control and prevent wheel lock-up for safer braking.
advantages of anti lock braking system
The Anti lock Braking System (ABS) offers several advantages:
- Improved Steering Control: ABS helps maintain steering control during emergency braking situations. By preventing the wheels from locking up, it allows the driver to steer the vehicle while applying maximum braking force. This helps avoid obstacles and maintain stability.
- Shorter Braking Distances: ABS helps reduce braking distances on slippery or uneven surfaces. By modulating the brake pressure rapidly, it prevents wheel lock-up and allows the tires to maintain better traction with the road. This results in shorter stopping distances, which can be critical in avoiding accidents.
- Enhanced Stability and Stability: ABS enhances vehicle stability during braking. It prevents the vehicle from skidding or spinning out of control by preventing individual wheels from locking up. This is particularly beneficial in situations where sudden maneuvers or hard braking are required.
- Increased Control on Different Surfaces: ABS provides better control and braking performance on various road surfaces, such as wet, icy, or gravel roads. It adapts to the conditions and adjusts brake pressure accordingly, ensuring optimal braking performance.
- Reduced Risk of Accidents: By allowing drivers to maintain control and reducing braking distances, ABS helps minimize the risk of accidents. It enhances overall safety by preventing wheel lock-up and providing consistent braking performance.
- Compatibility with Other Safety Systems: ABS is compatible with other safety systems such as Electronic Stability Control (ESC) and Traction Control System (TCS). These systems work together to enhance overall vehicle safety and control.
disadvantages of anti lock braking system
Disadvantages of Anti Lock Braking System are:
- Longer stopping distances on loose surfaces.
- Pedal pulsation and feedback.
- Limited effectiveness in extreme conditions.
- Increased complexity and maintenance.
- Potential false activation and sensitivity.
- Reliance on proper tire condition.
applications of anti lock braking system
Applications of Anti lock Braking System are:
- Automotive Industry: ABS is widely used in cars, motorcycles, trucks, and other vehicles to improve braking performance and safety.
- Racing and Sports Vehicles: ABS is employed in racing cars and high-performance vehicles to enhance braking control and reduce stopping distances during intense driving situations.
- Commercial Vehicles: ABS is commonly found in commercial vehicles, such as buses, delivery trucks, and heavy-duty vehicles, to improve stability and control while braking, especially when carrying heavy loads.
- Off-Road Vehicles: ABS is utilized in off-road vehicles, including SUVs and 4×4 vehicles, to enhance braking effectiveness and maintain traction on uneven or slippery terrain.
- Motorcycles: ABS is increasingly being incorporated into motorcycles to prevent wheel lock-up and enhance stability during braking, particularly in emergency situations.
- Aircraft: ABS systems are employed in certain aircraft to prevent wheel lock-up during landing, ensuring effective braking and improving control on the runway.
- Industrial and Agricultural Equipment: ABS technology is also applied in industrial machinery, agricultural equipment, and construction vehicles to enhance braking performance, stability, and safety.
Source ; Wikipedia