polttoaineseoksia

Polttoaineseoksia, or fuel mixtures, refers to the combination of fuel and air that is introduced into an internal combustion engine for combustion. The precise ratio of fuel to air is critical for efficient and clean engine operation. This ratio is often expressed as the air-fuel ratio (AFR).

In gasoline engines, the ideal stoichiometric AFR is approximately 14.7:1 by mass, meaning 14.7 parts of air are mixed with 1 part of fuel. Deviations from this ideal ratio affect performance, emissions, and fuel economy. A rich mixture, with more fuel than stoichiometric, can provide more power but results in higher fuel consumption and increased emissions of unburned hydrocarbons. A lean mixture, with less fuel than stoichiometric, improves fuel economy and reduces certain emissions but can lead to higher combustion temperatures and potentially engine damage if too lean.

Diesel engines operate differently. They typically use a much leaner AFR, with excess air, and rely on compression ignition. The fuel is injected directly into the cylinder during the compression stroke, where it ignites due to the high temperature and pressure.

Modern engines use sophisticated electronic control units (ECUs) to precisely manage the fuel mixture based on various sensor inputs, such as oxygen sensors, throttle position, engine speed, and air temperature. This ensures optimal performance and emissions control under different operating conditions. The type of fuel, such as gasoline, diesel, ethanol, or natural gas, also dictates the ideal AFR and the engine's combustion characteristics.