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1. Vacuum Booster as a Diaphragm Pump:
- Function: In some older vehicle designs, a small diaphragm vacuum pump, often in combination with the fuel pump, is used to supplement engine vacuum during acceleration. This additional vacuum helps maintain the operation of vacuum-operated devices such as power brakes, HVAC controls, and emissions control systems.
- Operation: The vacuum booster draws air out of the intake manifold or other sources to create a vacuum, which is then used to power various vacuum-operated systems in the vehicle.
2. Vacuum Booster as a Power Brake Actuator:
- Function: In modern vehicles, a vacuum booster is a power brake actuating mechanism that uses vacuum as a power source. It assists in applying the brakes by using vacuum on one side of a diaphragm to amplify the force exerted on the brake pedal by the driver.
- Operation: When the driver presses the brake pedal, a valve opens, allowing engine vacuum to act on one side of a diaphragm within the booster. The pressure differential between the vacuum side and the atmospheric side of the diaphragm assists in applying the brakes, reducing the amount of effort required by the driver.
Types of Vacuum Boosters:
- Integral Vacuum Booster: This type of vacuum booster is integrated into the master cylinder assembly, combining the functions of brake actuation and vacuum assistance in one unit.
- Multiplier Vacuum Booster: This type of vacuum booster uses a separate housing or unit to multiply the force applied by the driver on the brake pedal. It is often mounted remotely from the master cylinder.
Vacuum boosters are critical components in power brake systems, providing additional force to assist in brake application and ensuring safe and efficient braking performance in vehicles.
See
- Integral Vacuum Booster
- Multiplier Vacuum Booster