Hello readers, today I am going to discuss the Braking Systems of Automobile.
As we all know an automobile is consist of various types of system like lighting system, ignition system, air-conditioning system, etc. etc. Among all these systems, the braking system is one of the most important system.
Being a Mechanical Engineer you should know about all these systems, so today start with the braking system. Let me tell you the definition of the braking system first.
Definition of Brake System:
A brake is one of the most important controls of the vehicle. This is a combination of some interactive parts. It absorbs energy from the moving part and slows down the vehicle with the help of friction.
Every vehicle has its own braking system to stop that vehicle. Below I mentioned the generally used braking systems in automobile
Functions of Brake System:
The function of the brake system is to stop the vehicle within the smallest possible distance and hence this is done by converting the kinetic energy of the vehicle into the heat energy which is dissipated into the atmosphere.
Types of Brake System in Automobile:
The brake system in an automobile can be classified into these following categories:
- Mechanical Brake
- Disc Brake
- Hydraulic Brake
- Power-assisted Brake
- Air Brake
- Electric and
- Hand brake System
Let me go through all these break systems.
The mechanical brake is used in small power automobiles like scooters, motorcycles and some modern vehicles. The figure of the mechanical brake is shown below:
As the brake pedal is pressed cam rotates, which pushes the brake shoes outwards and hence brake lining provided on the outer surface of the shoes rub against rotating the drum and hence slow down or stops the vehicles because the drum is connected to the wheels.
As the pedal is released, due to retracting spring force shoes return to its original position.
The disc brake is used in motor vehicles and cars, etc.
When the pedal is pressed piston pushes the pad by the pressure of the hydraulic fluid. The diagram is shown below:
These friction pad rub against the rotating disc connected to the wheels of the vehicle and thus braking takes place.
And as the pedal is released friction pad returns to its original position between the pressure of hydraulic fluid reduces.
Hydraulic brake works on the principle which is based on Pascal’s principle, which states that “confined liquid transmits pressure without loss in all direction”.
This is simple in construction and has an equal braking effort to all wheels and smooth operation.
When the brake pedal is pressed, fluid from the master cylinder enters into the wheel cylinders through pipelines by the force of the piston.
Due to the liquid force, the piston of the wheel cylinder pushes outward which pushes the shoes outward.
Lining rub against the drum and hence braking take place.
Now when the pedal is released, the piston of the master cylinder moves backward and fluid from the wheel cylinder moves to the master cylinder through the check valve.
This type is commonly used in all cars etc.
The master cylinder is the heart of the hydraulic brake system.
It consists of two chambers:
- The reservoir.
- Compression chamber, in which piston reciprocates.
The piston is connected to the brake pedal through the piston rod. From the reservoir, fluid enters the compression chamber through the parts as shown.
The master cylinder is connected to the wheel cylinder through the pipe.
The check valve is provided in order to give passage for entering fluid from the wheel cylinder to the master cylinder when the pedal is released.
See the below animation for a clear understanding.
Power-assisted or Vacuum brake:
The line diagram indicates the construction of a power-assisted or vacuums brake as shown below.
As the brake pedal is pressed, the fluid pressure causes the upper valve of a control unit to open and lower the valve to close.
Thus left the side of the servo cylinder piston is exposed to atmosphere and vacuum acts on the right side, which causes the braking effort.
Braking takes place by suction from the engine inlet manifold.
This type of air brake system is commonly used in heavy vehicles such as buses, trucks, etc.
In this also when the brake pedal is pressed, air to atmosphere enters the compressor through the air filter to the reservoir through unloader value.
From unloader valve air enter brake chamber through brake valve.
Brake valve is fitted in order to control the intensity of braking. Thus braking takes place.
When the pedal is pressed shoes return to its original through position through the spring force.
Girling Mechanism Brake:
This system consists of an expander used for braking and adjuster unit to adjust the brake shoes when desired.
As the brake pedal is pressed, the pulls rod of expander pulled out which pulls out the conical wedge.
The brake shoe connected to the conical wedge through plunger and steel roller ball pulls outward. Thus braking the wheel.
When the pedal is released, spring force brings the brake shoe to its original position.
It requires less friction. Without jacking up vehicles brakes can be adjusted.
Electrical Brake System:
The principle of working of this type of brake is to utilize the electromagnetic force on the brake shoes.
It consists of an electromagnet, armature disc.
An electromagnet is mounted on the backplate and armature disc is fed to the drum.
This is simple in construction.
For working, electric current for the battery is utilized to energize the electromagnet which actuates the cams that expands the shoes. Thus braking the wheel.
Hand brake System:
Hand brakes or the parking brakes operate independently of the foot brakes.
These are used for parking on slopes or while waiting at traffic lights, where the handbrake function is mainly to minimize accidents.
This brake is applied after the foot brake is applied.
These are mechanical brakes.
Apart from the hydraulic braking system, all cars have a mechanical handbrake acting on two wheels – usually the rear ones
The handbrake gives limited braking if the hydraulic system fails completely, but its main purpose is as a parking brake.
The handbrake lever pulls a cable or pair of cables linked to the brakes by a set of smaller levers, pulleys, and guides whose details vary greatly from car to car.
A ratchet on the handbrake lever keeps the brake on once it is applied. A push-button disengages the ratchet and frees the lever.
On drum brakes, the handbrake system presses the brake linings against the drums.
Disc brakes sometimes have a comparable handbrake arrangement, but because it is difficult to place the linkage on a compact caliper, there may be a completely separate set of handbrake pads for each disc.
Here are a couple of interesting videos on Braking System:
How does a motorcycle’s brake work?
How ABS work?
This is an interesting topic, hopefully, in the future, I will write an article on this topic, but till then enjoy this awesome video by Learn Engineering.
A Short Summary:
What is a braking system?
What are the types of braking systems?
So, I hope you learned about the braking system and types of braking systems used in the automobile.
Now let’s play quiz 🙂
Now I want to hear from you. If you like my article do share with your friends and also on your social handles. And also you can comment down below your doubts, or whatever you wanna tell me. I love to hear your opinion and suggestions.
We also have dedicated Facebook community for you guys, if you wish you can join our community, here is the link of our Facebook group. So, Cheers, and enjoy the rest of your day.
- Read all the articles related to Automobile Engineering here