the ratio of fluid delivered by a piston or ram pump per stroke to the displacement volume of the piston or ram
2.
the ratio of air or gas-air mixture drawn into the cylinder of an internal-combustion engine to the volumetric displacement of the piston
volumetric efficiency in Automotive Engineering
(vɒlyəmɛtrɪk ɪfɪʃənsi)
noun
(Automotive engineering: Design and performance)
The volumetric efficiency of an engine is the extent to which the cylinder is completely filled by the air/fuel mixture that enters on each exhaust stroke. This measures the ability of an engine to breathe freely.
The easier the engine breathes, the greater its volumetric efficiency, and the more power it produces.
The volumetric efficiency of an engine can be reduced by restricting the airflow in and out of the engine.
Volumetric efficiency is how an engine's pumping capacity is defined.