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power brake
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Labeled diagram of a vacuum-activated power brake system in a car, showing the brake pedal, master cylinder, brake booster chamber, pistons, valves, and airflow, with arrows and text explaining how pressing the pedal uses vacuum and atmospheric pressure to assist braking.
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power brake

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Labeled diagram of a vacuum-activated power brake system in a car, showing the brake pedal, master cylinder, brake booster chamber, pistons, valves, and airflow, with arrows and text explaining how pressing the pedal uses vacuum and atmospheric pressure to assist braking.
vacuum-assisted power brake Vacuum-assisted power brake for an automobile. A constant vacuum is maintained in the brake booster by the engine. When the brake pedal is depressed, a poppet valve opens, and air rushes into a pressure chamber on the driver's side of the booster. The pressure exerted by this air against the vacuum pushes a piston, thus assisting the pressure exerted by the driver on the pedal. The piston in turn exerts pressure on the master cylinder, from which brake fluid is forced to act on the brakes.

A power brake is an automotive brake system that uses engine power to amplify the torque applied by the driver at the pedal. This system is a crucial component of modern automobiles, designed to assist in stopping the vehicle more effectively than purely mechanical systems.12

Originally, vehicles used mechanically actuated drum brakes. As cars became heavier and faster, these brakes required increasing effort from the driver. Hydraulic systems replaced mechanical ones, offering better force multiplication. However, even hydraulic brakes could be difficult to operate with greater vehicle demands, leading to the development of power brake systems. These systems work similarly to hydraulic brakes but incorporate power assists to multiply the force applied to the master cylinder piston, reducing the physical effort needed from the driver.2

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2 Britannica Sources
  1. power brake
  2. automobile - Brakes

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