Air–Fuel Ratio
Air–Fuel Ratio
The air–fuel ratio sets combustion completeness, efficiency and emissions — the number every engine is tuned around.
The ratio is AFR = m_air/m_fuel. where m_air is the air mass and m_fuel the fuel mass.
Inputs
m_air := 14.7 kg=14.7 kg
m_fuel := 1 kg=1 kg
Divide air mass by fuel mass.
AFR := m_air/m_fuel=14.7
Results
A ratio of 14.7 is stoichiometric for petrol — exactly enough air to burn the fuel. Higher is lean (more air), lower is rich.
Assumptions & limitations
- Mass basis.
- Complete combustion at stoichiometric.
- Single fuel.