What are the consequences of an overly lean air-fuel mixture?
2 Answers
The consequences of an overly lean air-fuel mixture are: it will reduce the combustion speed of the fuel, and part of the mixture's combustion will occur when the piston moves toward the bottom dead center. The combustion of this part of the mixture not only converts a relatively smaller proportion of the released heat into mechanical work but also increases the heat lost through the cylinder wall to the cooling water or radiator fins. Therefore, an overly lean mixture can cause engine overheating, reduced power output, and may also lead to irregular engine operation or failure to start. The air-fuel mixture in a car is a blend of fuel and air, typically referring to mixtures of gasoline, diesel, etc., with air. However, with advancements in automotive technology and the diversity of fuels, mixtures now also include various combustible gases such as natural gas, methane, coal gas, as well as ethanol, methanol, and other mixtures.
I've been driving for years, and a lean fuel mixture is no small matter. It makes the engine shake upon starting, as if the car is trembling, and it's particularly sluggish during acceleration. Climbing hills is a real struggle, and even with the pedal to the metal, the speed won't pick up. The engine temperature tends to spike, and in severe cases, it can cause knocking—those annoying knocking sounds. Over time, the pistons can burn out or the cylinders can get damaged, leading to costly repairs. Emissions also worsen, releasing more harmful gases like nitrogen oxides that pollute the environment and harm air quality. Fuel consumption actually increases because the engine isn't running efficiently, wasting fuel. So if you notice difficulty starting the car or unstable idling, get the air-fuel ratio system checked at a professional shop right away. Don't slack on regular maintenance.
