What makes a vacuum in an internal combustion engine?
What makes a vacuum in an internal combustion engine? Manifold vacuum, or engine vacuum in an internal combustion engine is the difference in air pressure between the engine's intake manifold and Earth's atmosphere. Manifold vacuum is an effect of a piston's movement on the induction stroke and the choked flow through a throttle in the intake manifold of an engine. How does the vacuum system work in a car? Older vehicles with distributors use vacuum as a means to advance spark timing in the ignition system. The EGR and PVC valve use vacuum to function as part of the emission...