ilmanpolttoainesuhdetta

Ilmanpolttoainesuhde, often abbreviated as A/F ratio, refers to the mass ratio of air to a combustible fuel in an air-fuel mixture. This ratio is critical for efficient and complete combustion in engines and other combustion devices. In internal combustion engines, the ideal air-fuel ratio for gasoline is approximately 14.7:1 by mass, known as the stoichiometric ratio. At this ratio, all the fuel is theoretically burned with the available oxygen, producing carbon dioxide and water.

Deviations from the stoichiometric ratio can significantly impact engine performance, fuel economy, and emissions. A rich mixture, where there is more fuel than air (A/F ratio less than 14.7:1), can lead to incomplete combustion, increased carbon monoxide and unburned hydrocarbon emissions, but may provide more power and prevent engine damage from excessive heat. A lean mixture, where there is more air than fuel (A/F ratio greater than 14.7:1), results in more complete combustion and lower fuel consumption, but can also increase nitrogen oxide (NOx) emissions and potentially lead to engine overheating if too lean.

Modern engines utilize oxygen sensors and engine control units (ECUs) to constantly monitor and adjust the air-fuel ratio in real-time, aiming to optimize combustion based on various operating conditions such as engine load, speed, and temperature. This precise control is essential for meeting stringent emissions regulations and maximizing fuel efficiency. Understanding and managing the air-fuel ratio is a fundamental principle in combustion engineering.