The phase of internal combustion where the downward stroke of the piston creates a vacuum, pulling fresh air or a combustible mixture into the cylinder through the open intake valve. In naturally aspirated engines, this relies entirely on atmospheric pressure. Forced induction systems use compressors to push air in at higher pressures, significantly increasing engine power.
Heard on the job
We need to check the induction system for vacuum leaks before throwing parts at a lean code.
Related terms
Forced induction
The process of compressing intake air to increase the power output of an internal combustion engine.
Intake system
The complete path that channels outside air into the engine combustion chambers.
Intake valve
A mechanical valve in the cylinder head that opens to allow air into the combustion chamber.