What do we call the extra air that passes through the combustion chamber beyond what is needed for complete combustion?

The term used to describe the extra air that passes through the combustion chamber, beyond what is necessary for complete combustion, is "excess air." In a combustion process, complete combustion occurs when fuel burns with just the right amount of air, resulting in minimal unburned fuel and byproducts. However, in practice, it is typical to introduce more air than needed to ensure efficient combustion and prevent the formation of harmful emissions.

Excess air plays a critical role in achieving a clean burn; it helps to promote better mixing of the fuel and air, allowing more complete combustion and reducing the production of carbon monoxide and other pollutants. The concept is essential in ensuring that combustion systems operate safely and efficiently, as maintaining the right balance of air can directly impact the performance of heating appliances and engines that rely on combustion.

The other options pertain to different aspects of air usage in combustion systems. For instance, "combustion air" refers explicitly to the air required for combustion, while "draft air" relates to the air being drawn into the system to support combustion and maintain pressure balance. "Dilution air" typically refers to the air mixed with exhaust gases for the purpose of reducing concentration levels of harmful substances, but it does not specifically address the concept of