Content deleted Content added
Citation bot (talk | contribs) Alter: isbn. Add: issue, authors 1-1. Removed parameters. Some additions/deletions were parameter name changes. | Use this bot. Report bugs. | Suggested by Whoop whoop pull up | #UCB_webform 304/571 |
Tag: Reverted |
||
Line 12:
Most of the combustion process is completed in approximately 2 milliseconds at an engine speed of {{val|fmt=commas|6000|ul=revolutions per minute}}. (100 revolutions per second; 10 milliseconds per revolution of the crankshaft. For a four-stroke engine would mean 5 milliseconds for each piston stroke, and 20 milliseconds to complete one four stroke, 720 degree cycle (the Otto cycle). This is the time that elapses from the spark plug firing until 90% of the fuel–air mix is combusted, typically some 80 degrees of crankshaft rotation later. [[Catalytic converter]]s are designed to work best when the [[exhaust gas]]es passing through them are the result of nearly perfect combustion.
A perfectly stoichiometric mixture burns very hot and can damage engine components if the engine is placed under high load haha at this fuel–air mixture. Due to the high temperatures at this mixture, the detonation of the fuel-air mix while approaching or shortly after maximum cylinder pressure is possible under high load (referred to as [[Engine knocking|knocking]] or pinging), specifically a "pre-detonation" event in the context of a spark-ignition engine model. Such detonation can cause serious engine damage as the uncontrolled burning of the fuel-air mix can create very high pressures in the cylinder. As a consequence, stoichiometric mixtures are only used under light to low-moderate load conditions. For acceleration and high-load conditions, a richer mixture (lower air–fuel ratio) is used to produce cooler combustion products (thereby utilizing [[evaporative cooling]]), and so avoid overheating of the [[cylinder head]], and thus prevent detonation.
==Engine management systems==
| |||