Volumetric Efficiency

Volumetric efficiency, abbreviated as \( \eta_v \) (Greek symbol eta), a dimensionless number, is the calculation for an internal combustion engine.  This is the calculation for the volumetric efficiency for an internal combustion engine.  For a thermal engine, the combustion process depends on the air-fuel ratio inside the cylinder.  The more air inside the combustion chamber, the more fuel that can be burned and the higher the output engine torque and power.

 

Volumetric Efficiency Formula
\(\large{ \eta_v = \frac{3456 \; CFM}{CID \; RPM} }\)
Symbol	English	Metric
\(\large{ \eta_v }\)  (Greek symbol eta) = volumetric efficiency	\(\large{dimensionless}\)
\(\large{ CFM }\) = air flow in cubic feet per minute	\(\large{\frac{ft^3}{min}}\)	\(\large{\frac{m^3}{min}}\)
\(\large{ CID }\) = cubic inch displacement	\(\large{in^3}\)	\(\large{mm^3}\)
\(\large{ RPM }\) = pump revolution per minute	\(\large{\frac{r}{min}}\)	\(\large{\frac{r}{min}}\)

 

Motor Volumetric Efficiency Formula
\(\large{ \eta_v = \frac{ s \; 100 }{ TS } }\)
Symbol	English	Metric
\(\large{ \eta_v }\)  (Greek symbol eta) = volumetric efficiency	\(\large{dimensionless}\)
\(\large{ s }\) = speed	\(\large{\frac{ft}{sec}}\)	\(\large{\frac{m}{s}}\)
\(\large{ TS }\) = theoretical speed	\(\large{\frac{ft}{sec}}\)	\(\large{\frac{m}{s}}\)

 

Punp Volumetric Efficiency Formula
\(\large{ \eta_v = \frac{ GPM \; 100 }{ TF } }\)
Symbol	English	Metric
\(\large{ \eta_v }\)  (Greek symbol eta) = volumetric efficiency	\(\large{dimensionless}\)
\(\large{ GPM }\) = flow in gallon per minute	\(\large{\frac{gal}{min}}\)	\(\large{\frac{l}{min}}\)
\(\large{ TF }\) = theoretical flow	\(\large{\frac{ft}{sec}}\)	\(\large{\frac{m}{s}}\)

 

Volumetric Efficiency calculator