ilmanpolttoainesuhde

Ilmanpolttoainesuhde, often abbreviated as A/F ratio, refers to the mass ratio of air to fuel present in a combustion process. This ratio is a critical factor in determining the efficiency and emissions of internal combustion engines. A stoichiometric or chemically ideal A/F ratio is the precise amount of air required to completely burn a given amount of fuel. For gasoline, this is approximately 14.7:1, meaning 14.7 parts of air by mass are needed for 1 part of fuel by mass.

Deviations from the stoichiometric ratio have significant consequences. A rich mixture has more fuel than air (A/F ratio below 14.7:1), leading to incomplete combustion, reduced fuel economy, and increased carbon monoxide emissions. Conversely, a lean mixture has more air than fuel (A/F ratio above 14.7:1), which can result in higher combustion temperatures, potentially causing engine damage, and increased nitrogen oxide emissions. Modern engines utilize oxygen sensors (lambda sensors) to monitor the exhaust gases and adjust the fuel injection system to maintain the optimal A/F ratio for various operating conditions, thereby balancing performance, fuel efficiency, and emission control. Understanding and controlling the air-fuel ratio is fundamental to engine management.