AFR is an acronym that stands for "Air Fuel Ratio." It refers to a measurement of the air-fuel mixture in an internal combustion engine. The AFR determines the ratio of air to fuel required for the engine to operate efficiently and produce the desired amount of power.
In an internal combustion engine, a precise AFR is critical for optimal performance. The ratio is expressed as the amount of air compared to the amount of fuel required for combustion. AFR is typically represented as a numerical value (e.g., 14.7:1) or a lambda value (e.g., 1.0). The value or lambda represents the ideal stoichiometric ratio, which is the chemically balanced ratio of air and fuel that ensures complete combustion without excess fuel or oxygen.
Monitoring and controlling the AFR in an engine is important for several reasons. A rich mixture, where there is excess fuel relative to the available oxygen, can lead to incomplete combustion, reduced power output, and increased emissions. Conversely, a lean mixture, where there is excess oxygen relative to the available fuel, can result in decreased power and increased risk of detonation.
To achieve the correct AFR, modern vehicles are equipped with various sensors, including oxygen or lambda sensors, to measure the oxygen content in the exhaust gases. This information is then used by the engine control unit (ECU) to adjust the fuel injection accordingly, ensuring that the AFR remains within the desired range for optimal performance, fuel efficiency, and emissions control.
