Editing Wankel engine (section)

{{Short description|Combustion engine using an eccentric rotary design}}
{{About|a particular pistonless rotary engine|other pistonless rotary engines|pistonless rotary engine|piston designs arranged in a rotary configuration|rotary engine}}

[[File:Wankel Cycle anim en.gif|right|frame|'''Figure 1.'''<br/>The Wankel KKM cycle: {{bulleted list |'''A''': Apex of the rotor.|'''B''': The eccentric shaft.|The white portion is the lobe of the eccentric shaft.|The distance between A and B remains constant.|Produces three power pulses each revolution of the rotor.|Gives one power pulse per revolution of the output shaft.}}]]

The '''Wankel engine''' ({{IPA|/ˈvaŋkəl̩/}}, {{respell|VUN|kell}}) is a type of [[internal combustion engine]] using an [[eccentric (mechanism)|eccentric]] [[rotary combustion engine|rotary design]] to convert pressure into rotating motion. The concept was proven by German engineer [[Felix Wankel]], followed by a commercially feasible engine designed by German engineer Hanns-Dieter Paschke.<ref>{{cite web |title=A Brief History of the Rotary Engine |url= http://rotaryrevs.com/garage/help/rotary-engine-information/brief-history/ |website=rotaryrevs.com |access-date=November 6, 2023}}</ref> The Wankel engine's rotor, which creates the turning motion, is similar in shape to a [[Reuleaux triangle]], with the sides having less curvature. The rotor spins inside a figure-eight-like [[epitrochoid]]al housing around a fixed-toothed gearing. The midpoint of the rotor moves in a circle around the output shaft, rotating the shaft via a cam.

In its basic gasoline fuelled form, the Wankel engine has lower [[thermal efficiency]] and higher exhaust emissions relative to the four-stroke reciprocating piston engine. The thermal inefficiency has restricted the engine to limited use since its introduction in the 1960s. However, many disadvantages have mainly been overcome over the succeeding decades as the production of road-going vehicles progressed. The advantages of compact design, smoothness, lower weight, and fewer parts over the reciprocating [[piston engine|piston]] internal combustion engines make the Wankel engine suited for applications such as [[chainsaw]]s, [[auxiliary power unit]]s (APUs), [[loitering munition]]s, [[aircraft]], [[personal water craft|jet skis]], [[snowmobile]]s, and [[range extender|range extenders in cars]]. The Wankel engine was also used to power [[motorcycle]]s and [[racing car]]s.