OCTOBER 19-20, 2012 - YMCA University of Science & Technology

Proceedings of the National Conference on
Trends and Advances in Mechanical Engineering,
YMCA University of Science & Technology, Faridabad, Haryana, Oct 19-20, 2012
exists to multiply the force exerted by the driver’s foot, the force increase will be equal to the driver’s applied
force multiplied by the lever ratio of the brake pedal assembly, F b =F d ×(L 2 /L 1 ).
Master cylinder translate the force from the brake pedal assembly into hydraulic fluid pressure. The pressure
generated by the master cylinder will be P MC =F bp /A MC
Caliper translate the hydraulic fluid pressure from the pipes and hoses into a linear mechanical force. The onesided
linear mechanical force generated by the caliper will be F cal =P cal xA cal and P MC =P cal
1.2 Brake System Components
It consist of Brake booster, Master cylinder, Disc Brakes, Drum Brakes. The working of these components of
brake system are explained hereunder.
Brake Booster: The typical brake booster shown in Fig. 1; the basic principle of the brake booster is pressure
differential, when vacuum is applied to both sides of the diaphragm piston it is pushed to the right by the spring
and remains there. When the brake pedal is pressed it causes the plunger to move inside brake booster and
atmospheric air is allowed into variable pressure chamber. Due to the difference in pressure the piston starts to
compress the spring and moves to the left. This causes the piston rod to move the piston of the master cylinder
and generating hydraulic pressure.
Fig. 1 Brake Booster
Master Cylinder: The typical master cylinder is shown in Fig. 2; when the brake pedal is de-pressed, the primary
piston moves to the left. As the primary piston is pushed fartherit builds hydraulic pressure inside the master
cylinder which is transmitted to the wheel cylinders of the rear brake. The same hydraulic pressure is applied to
the secondary piston, and hydraulic pressure in the primary chamber moves the secondary piston to the left, after
the compensating port of the secondary chamber is closed, hydraulic pressure builds and is transmitted to the
brake caliper of front brake.
Fig. 2 Master Cylinder with Reservoir
Drum Brakes: It consist of wheel cylinder, brake shoes shown in Fig. 3; When the hydraulic pressure builds
inside the master cylinder, it is transmitted to the wheel cylinder and in turn it pushes piston on each end of the
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