If the intake valve opens too early in the cycle, vacuum will be reduced and exhaust gasses will be forced into the intake manifold. When exhaust gasses are forced into the intake manifold, vacuum is adversely affected and the intake runners will soot up. This effect is called "reversion".
An internal-combustion engine goes through four strokes: intake, compression, combustion (power), and exhaust. As the piston moves during each stroke, it turns the crankshaft.
The work of is intake valve opens when the piston reaches the TDC; compressed air from high pressure tank rapidly flows into the cylinder. The pressure inside the cylinder rapidly increases to the intake pressure. Meanwhile, the mass and temperature inside the cylinder increase.
To learn more about intake valve here
https://brainly.com/question/7383408
#SPJ4
