There are three main types of air-fuel mixtures as “lean fuel mixtures”, “stoichiometric fuel mixtures” and “rich fuel mixtures”.
Thus, this ratio is very important for the determination of the efficiency of the engine or furnace. The air-fuel ratio is a parameter regarding internal combustion engines and industrial furnaces. Before analyzing the difference between lean and rich fuel mixture, it is important to know more about the air-fuel ratio. We use the terms lean and rich fuel mixtures to describe combustion processes in engines and industrial furnaces. The key difference between lean and rich fuel mixture is that we use a lean mixture for maximum efficiency while we use a rich mixture for maximum power in an engine.