Sae Grade Oil

Overview

Engineering reference data for Sae Grade Oil in combustion engineering.

Key Formulas

Heat Release

$Q = \dot{m} \cdot HV$

Fuel energy release rate.

Air-Fuel Ratio

$AF = \frac{m_{air}}{m_{fuel}}$

Mass of air per mass of fuel.

Excess Air

$EA = \frac{O_2}{21 - O_2} \times 100\%$

From flue gas oxygen measurement.

Variables

Symbol	Description	Unit
$Q$	Heat release rate	W
$\dot{m}$	Mass flow rate	kg/s
$HV$	Heating value	J/kg
$AF$	Air-fuel ratio	—

SAE Multigrade Oil Properties

Key Definitions

• SAE Multigrade Oil: An oil that meets the viscosity requirements of multiple SAE grades across a range of temperatures, indicated by a dual rating (e.g., 10W-40). The "W" stands for Winter.
• Viscosity (cSt or Centistokes): A measure of a fluid's resistance to flow. Kinematic viscosity (ν) is the ratio of dynamic viscosity (μ) to density (ρ), commonly expressed in centistokes (1 cSt = 10⁻⁶ m²/s).
• Dynamic Viscosity (Reyn): A measure of internal fluid friction. The reyn (1 µreyn = 10⁻⁶ lb·s/in²) is a unit used in imperial engineering contexts.

Interactive Charts

References

• Original Source