All About Air Brakes — Carengineered.com

Introduction

Braking is the department that may have a limit in its functioning that is ‘To Apply Brakes and stop the vehicle’ but as far as its significance is concerned, it forms yest the most crucial of all.

Let’s take a situation of owning a car that may have the most powerful engine, say a V-12 or W-16 or W-18 configuration, an automatic transmission system with turbocharger/ supercharger equipped and 4-wd or Awd and is capable of attaining top speed within a blink of an eye.

Now with all such classic, unbeatable configurations if the car is not able to be stop then it would automatically be the last ride/drive of the driver and passengers accompanying him.

Therefore, it makes it necessary for the vehicle to be very well equipped with some sort of mechanism/system in order to reduce the car and gradually allowing is to stop without any further complications.

Also, it would rather suggest a car that do not compromise on such types of crucial takes.

Now as we have learnt about why do we need brakes, let us go into a brief understanding on what are brakes and how they function and types of braking system/brakes.

What are Brakes?

Brakes are a mechanical system/mechanism which restricts a certain motion of any object/device and is able to absorb the energy.

What are different types of brakes?

On the basis of power

• Mechanical Brakes
• Hydraulic Brakes
• Air Brakes
• Vacuum Brakes
• Power assisted Hydraulic Brakes
• Mechanical Brakes
• Electrical Brakes
• By method of Application
• Foot Brakes
• Hand Brakes

Method of operation

• Manual
• Servo
• Power operation

Method of Braking Contact

• Internal Expanding Brakes
• External Contracting Brakes

Method of applying brakes force

• Single Acting Brakes
• Double Acting Brakes

Let us discuss on Air Brakes in this blog.

Air Brakes

Air Brake system or more technically The Compressed Air Brake System is a type of braking system/Frictional Braking System that uses high pressure of compressed air as a medium to fully functionalize the working braking mechanism.

This type of braking system is usually employed in Heavy Duty vehicles in which the highly compressed air is used to exert the pressure on the pistons that in turn pushes the brake pads against the wheel and hence opposes the movement of the wheel.

Due to this opposing nature a large amount of frictional force is generated and hence the wheel stops.

The main areas of their application are Trucks with or without multiple trailers, buses, semi-trailers, Railways and etc.

Components of Air Braking System

Air Compressors

The air compressors used in are generally a double acting compressors.

This compressor takes up the fresh air from the atmosphere and then it is compressed in its 1st cylinder, such that its volume decreases.

Then again the compressed air is sent into the 2nd cylinder of the compressor where it is further compressed to a certain limit as required.

These compressors are powered from the engine either by the belt or chain or by gear set arrangement.

The compressor is in on a constant drive with the engine.

Air Compressor Governor

It is a device that is used to control the pressure of the air transfered from the compressor to the reservoir.

Reservoir

These are storing tanks that are used to accumulate/store the compressed air that can be used at the time of braking.

These Reservoirs are of different shapes and sizes for each vehicle depending upon the numbers of braking chambers and also the parking brakes configuration.

Air Dryer

It is a device that may be installed in between the compressor and the reservoir, and is used to remove the moisture in the compressed air.

It can be either filled with moisture absorbing material and oil or may be hollow with the baffles designed to eliminate the moisture content from the compressed air.

Safety Valve

It is one of the main component.

It consists of a spring loaded ball that would open up in the case of malfunctioning of the governor and let the extra amount of the air that is already compressed by the compressor and directed into the storage/reservoir tank.

Hence it safe guards the storage tank from bursting up.

Foot Valve

As clear from the name itself is a valve that is indirectly operated by the driver.

When the driver presses the brake pedal, it allows the foot valve to press down and it allows the compressed air to be released from the reservoir into the brake chamber and excessive air is released into the atmosphere through the exhaust port.

This foot pedal is loaded with a spring mechanism and hence is automatically adjusted.

Brake Chamber

The Brake Chamber receives the compressed air from the foot valve.

This compressed air enters the into the diaphragm and compressed it.

The compressed diaphragm allows the push rod to move that again forces the slack adjuster to move.

This forces the pistons to move the brake pads opposing the rotation of the wheels, and hence the brakes are applied.

The brake Chamber is loaded with the spring mechanism that allows the mechanism to freturn back to their positions when the brake pedal is released.

Advantages

The supply from the compressor is unlimited, so it can never run out of its operating fluid unlike hydraulic system.

The air couplings and components are comparatively easy to manage, ie attached and detached and hence the air filling is removed unlike in hydraulic, where bleeding needs to be performed.

The air not only serves as a medium for force transmission but also stores potential energy and thus assists to brake with comparatively lesser force.

Air braking systems can also be used for various other purpose like air horns, etc unlike hydraulic.

The Air brakes are even effective with a leakage ad thus are somehow able to reduce the speed and apply brakes unlike in hydraulic system.

Disadvantages

Air Braking system are generally costlier.

The Air Brake system contains more number of components that increases the maintainence costs and also adds upon the weight.

They are difficult to operate smoothly.

Air Braking systems can sometimes be noisy.

At last, the driver needs to check the sir pressurization before the operation.

Originally published at https://www.carengineered.com on September 7, 2020.