What is described as perfect combustion?

Perfect combustion refers to the ideal process where a fuel burns completely with the precise amount of oxygen needed, resulting in no unburned fuel and no pollutants. This scenario utilizes the theoretical amount of air, which is the exact stoichiometric quantity needed to combust the fuel fully. In this conditions, the carbon in the fuel converts entirely into carbon dioxide, and the hydrogen converts to water vapor, leaving no residual ashes or pollutants.

Burning with excess air can lead to heat losses and incomplete combustion products, while burning with 100% efficiency is a theoretical concept that doesn't typically occur in practical applications due to various inefficiencies that always exist. Although burning with minimal pollutants is beneficial, it does not inherently imply that the combustion is perfect unless all fuel is fully consumed with the exact theoretical air requirement. Thus, the most accurate definition of perfect combustion is the scenario where the fuel and air are ideally balanced for complete conversion.