What are the two control valves in a vacuum brake booster?

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Multiple Choice

What are the two control valves in a vacuum brake booster?

The boost in a vacuum brake booster is controlled by two air-flow valves that regulate how air moves into and out of the booster’s diaphragm chamber. One is a vacuum valve (a one-way check valve) that keeps the booster filled with engine vacuum and stops air from escaping back toward the engine. This maintains assist even if engine vacuum fluctuates. The other is an atmospheric valve that vents the booster to the outside air, allowing air from the atmosphere to enter the front chamber when you apply the brakes. This venting changes the pressure on the diaphragm to create the braking assist. So the two control valves are the vacuum valve and the atmospheric valve. The other options describe valves that aren’t the ones used to manage the booster’s vacuum and venting.

The boost in a vacuum brake booster is controlled by two air-flow valves that regulate how air moves into and out of the booster’s diaphragm chamber. One is a vacuum valve (a one-way check valve) that keeps the booster filled with engine vacuum and stops air from escaping back toward the engine. This maintains assist even if engine vacuum fluctuates. The other is an atmospheric valve that vents the booster to the outside air, allowing air from the atmosphere to enter the front chamber when you apply the brakes. This venting changes the pressure on the diaphragm to create the braking assist.

So the two control valves are the vacuum valve and the atmospheric valve. The other options describe valves that aren’t the ones used to manage the booster’s vacuum and venting.

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