HomeCalculatorsExcess Air Factor λ from Exhaust O₂

Excess Air Factor λ from Exhaust O₂

Back-calculate λ = AFR / AFR_stoich from measured exhaust-gas oxygen percentage.

CombustionEmissions
Excess air factor λ
2.33 -
Formula, assumptions, and limits

Simplified dry-basis formula valid for hydrocarbon fuels with negligible fuel-bound oxygen. Marine diesels run λ 2.0–3.5 at full load → exhaust O₂ 10–15 %. Boilers target λ ≈ 1.15–1.25 → O₂ 3–4 %.

Symbol legend

SymbolMeaningUnitSource
Oxygen in dry exhaust% v/vportable analyser / CEMS
Excess-air factor - result