Editing Combustion (section)

====Incomplete====
{{see also|Charring}}
Incomplete combustion will occur when there is not enough oxygen to allow the fuel to react completely to produce carbon dioxide and water. It also happens when the combustion is quenched by a heat sink, such as a solid surface or flame trap. As is the case with complete combustion, water is produced by incomplete combustion; however, [[carbon]] and [[carbon monoxide]] are produced instead of carbon dioxide.

For most fuels, such as diesel oil, coal, or wood, [[pyrolysis]] occurs before combustion. In incomplete combustion, products of pyrolysis remain unburnt and contaminate the smoke with noxious particulate matter and gases. Partially oxidized compounds are also a concern; partial oxidation of ethanol can produce harmful [[acetaldehyde]], and carbon can produce toxic carbon monoxide.

The designs of combustion devices can improve the quality of combustion, such as [[Oil burner|burners]] and [[internal combustion engines]]. Further improvements are achievable by [[catalytic]] after-burning devices (such as [[catalytic converter]]s) or by the simple partial return of the [[exhaust gas]]es into the combustion process. Such devices are required by [[environmental legislation]] for cars in most countries. They may be necessary to enable large combustion devices, such as [[thermal power station]]s, to reach legal [[emission standards]].

The degree of combustion can be measured and analyzed with test equipment. [[HVAC]] contractors, [[firefighters]] and [[engineers]] use combustion analyzers to test the [[Fuel efficiency|efficiency]] of a burner during the combustion process. Also, the efficiency of an internal combustion engine can be measured in this way, and some U.S. states and local municipalities use combustion analysis to define and rate the efficiency of vehicles on the road today.

Carbon monoxide is one of the products from [[incomplete combustion]].<ref>{{cite web|title=Incomplete combustion process|url=https://www.greenfacts.org/glossary/ghi/incomplete-combustion-processes.htm}}</ref> The formation of carbon monoxide produces less heat than formation of carbon dioxide so complete combustion is greatly preferred especially as carbon monoxide is a poisonous gas. When breathed, carbon monoxide takes the place of oxygen and combines with some of the hemoglobin in the blood, rendering it unable to transport oxygen.<ref>{{cite web|title=Burning showing incomplete combustion|url=https://www.sciencelearn.org.nz/resources/747-what-is-fire}}</ref>