What does a value greater than 1 for the excess air ratio (Lambda) indicate?

A value greater than 1 for the excess air ratio (Lambda) indicates that there is more air than is required for complete combustion of the fuel. This ratio is used to assess the amount of air supplied compared to the theoretical amount needed for combustion. When Lambda is greater than 1, it signifies that the combustion process has more air than the stoichiometric requirement, which is optimal for achieving complete combustion. This helps to reduce emissions of unburned hydrocarbons and other pollutants, as excess air provides better mixing and oxidation of the fuel, ensuring that almost all of it is consumed during the combustion process.

In contrast, a value less than 1 would indicate insufficient air, leading to incomplete combustion and potentially higher emissions of pollutants, while a value exactly equal to 1 would suggest a stoichiometric mixture, where fuel and air are mixed in the perfect ratio for complete combustion. A balanced mixture would imply an optimal condition for combustion but does not directly correspond to the excess air ratio concept.