Editing Wankel engine (section)

===Torque delivery===
Wankel engines are capable of high-speed operation, meaning they do not necessarily need to produce high torque to produce high power. The positioning of the intake port and intake port closing greatly affect the engine's torque production. Early closing of the intake port increases low-end torque, but reduces high-end torque (and thus power). In contrast, late closing of the intake port reduces low-end torque while increasing torque at high engine speeds, thus resulting in more power at higher engine speeds.<ref name="Bensinger 1973 p. 75">{{cite book |last1=Bensinger |first1=Wolf-Dieter |title=Rotationskolben-Verbrennungsmotoren |place=Berlin, Heidelberg, New York |date=1973 |isbn=978-3-540-05886-1 |oclc=251737493 |language=de |page=75}}</ref>

A peripheral intake port gives the highest [[mean effective pressure]]; however, side intake porting produces a more steady idle,<ref name="J6imC">Yamamoto, Kenichi. ''Rotary engine'', fig 4.26 & 4.27, Mazda, 1981, p. 46.</ref> because it helps to prevent blow-back of burned gases into the intake ducts, which cause "misfirings" caused by alternating cycles where the mixture ignites and fails to ignite. Peripheral porting (PP) gives the best mean effective pressure throughout the rpm range, but PP was also linked to worse idle stability and part-load performance. Early work by Toyota<ref name="SAE790435">{{citation |first1=T |last1= Kohno |publisher= Toyota |title= SAE paper 790435|display-authors=etal}}</ref> led to the addition of a fresh air supply to the exhaust port. It also proved that a Reed-valve in the intake port or ducts<ref name="pKO20">SAE paper 720466, Ford 1979 patent {{patent|CA|1045553}}</ref> improved the low rpm and partial load performance of Wankel engines, by preventing blow-back of exhaust gas into the intake port and ducts, and reducing the misfire-inducing high EGR, at the cost of a slight loss of power at top rpm. Elasticity is improved with a greater rotor eccentricity, analogous to a longer stroke in a reciprocating engine.

Wankel engines operate better with a low-pressure exhaust system. Higher exhaust back pressure reduces mean effective pressure, more severely in peripheral intake port engines. The Mazda RX-8 Renesis engine improved performance by doubling the exhaust port area relative to earlier designs, and there have been studies of the effect of intake and exhaust piping configuration on the performance of Wankel engines.<ref name="Z8UtD">Ming-June Hsieh et al. SAE papers</ref> Side intake ports (as used in Mazda's Renesis engine) were first proposed by Hanns-Dieter Paschke in the late 1950s. Paschke predicted that precisely calculated intake ports and intake manifolds could make a side port engine as powerful as a PP engine.<ref name="van Basshuysen Schäfer 2017 p. 487">{{cite book |last1=van Basshuysen |first1=R. |last2=Schäfer |first2=F. |title=Handbuch Verbrennungsmotor: Grundlagen, Komponenten, Systeme, Perspektiven |publisher=Springer Fachmedien Wiesbaden |series=ATZ/MTZ-Fachbuch |year=2017 |isbn=978-3-658-10901-1 |language=de |page=487}}</ref>