brandstofmengverhoudingen

Brandstofmengverhouding, also known as the air-to-fuel ratio (AFR), is the mass ratio of air to fuel in the combustible mixture used by internal combustion engines. It is a fundamental parameter that influences combustion efficiency, power, and exhaust emissions. The AFR can be expressed by mass or moles and is managed by fuel delivery systems, intake air measurement, and engine control units.

In gasoline engines, the AFR is controlled to achieve different operating goals. Fuel injectors or carburetors supply a precise amount of fuel based on signals from sensors such as the oxygen sensor (lambda sensor), mass air flow sensor, and throttle position. The engine control unit uses these measurements to maintain a target AFR, often the stoichiometric ratio, though lean or rich mixtures are used during cold start, acceleration, or high-load operation.

The stoichiometric AFR for pure gasoline is approximately 14.7:1 by mass, meaning 14.7 parts of air to one part of fuel. Ethanol blends or alternative fuels shift this value. Diesel engines, by contrast, typically run with excess air (lambda greater than 1) because they rely on compression ignition; their AFRs can be much higher and are managed with advanced aftertreatment to control NOx and particulates.

The choice of AFR affects fuel economy, thrust, spark timing, and emissions. Modern engines usually operate in closed-loop control, adjusting fuel delivery in real time to keep the mixture at or near the target ratio across operating conditions.