What is vacuum?

vacuum kicker

Glossary “vacuum kicker” Definition:
Computer controlled throttle device used to increase idle RPM during certain operating conditions, such as when the A/C system is in operation.

vacuum modulator

Glossary “vacuum modulator” Definition:
Component of the air-temperature sensor that regulates the amount of vacuum signal that is applied to the servo motor. It may also refer to a device which is used on some A/T to regulate shift points and or and pressure to engine torque and demands on the vehicle.

vacuum motor

Glossary “vacuum motor” Definition:
1). Device having a chamber containing a vacuum diaphragm used to create movement in a component, such as a heated air-intake blend door, when engine vacuum is routed to the chamber. 2). Device designed to provide mechanical control by the use of a vacuum.

vacuum hydraulic power unit

Glossary “vacuum hydraulic power unit” Definition:
Unit consisting of a vacuum brake cylinder or chamber, hydraulic cylinder(s), and control valve in which driver effort is combined with force from the cylinder piston or chamber diaphragm to displace fluid under pressure for actuation of the brake (s).

vacuum check valve

Glossary “vacuum check valve” Definition:
1). An air-operated mechanical device that closes a vacuum line to the vacuum reserve tank whenever the manifold vacuum pressure falls below the reserve vacuum pressure. 2). In a power-brake system, a one-way valve on the power brake boost that maintain vacuum within the unit when vacuum supply drops.

vacuum control valve

Glossary “vacuum control valve” Definition:
A ported vacuum switch. Controls vacuum to other emission devices during engine warm-up. The 2-port types simply open when engine coolant reaches their pre-determined calibration temperatures. The 4-port types open likewise, since they are nothing more than two, 2-port types in one housing. The 3-port types switch the vacuum source to the center port from the top or the bottom ports. Most VCV’s respond to a sensing bulb immersed in engine coolant by utilizing a wax pellet principle.

vacuum check relay

Glossary “vacuum check relay” Definition:
Mechanical, air-operated device that closes off a vacuum line to a port whenever the manifold vacuum pressure falls below the applied vacuum pressure.