Article
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Preserved in Portico This version is not peer-reviewed
Enhancing the Efficiency of Rotary Thermal Propulsion Systems
Version 1
: Received: 12 February 2024 / Approved: 13 February 2024 / Online: 15 February 2024 (03:43:17 CET)
A peer-reviewed article of this Preprint also exists.
Shen, X.; Costall, A.W. Enhancing the Efficiency of Rotary Thermal Propulsion Systems. Energies 2024, 17, 2112. Shen, X.; Costall, A.W. Enhancing the Efficiency of Rotary Thermal Propulsion Systems. Energies 2024, 17, 2112.
Abstract
Transport electrification is essential for reducing CO2 emissions, and technologies such as hybrid and range-extended electric vehicles will play a crucial transitional role. Such vehicles employ an internal combustion engine for on-board chemical energy conversion. The Wankel rotary engine should be an excellent candidate for this purpose, offering high power-to-weight ratio, simplicity, compactness, perfect balance, and low cost. Until recently, however, it has not been in production in the automotive market, due, in part, to relatively low combustion efficiency and high fuel consumption and unburnt hydrocarbon emissions, which can be traced to constraints on flame speed, an elongated combustion chamber, and relatively low compression ratios. This work uses large-eddy simulation to study the in-chamber flow in a peripherally ported 225cc Wankel rotary engine, providing insight into these limitations. Flow structures created during the intake phase play a key role in turbulence production but presence of the pinch point inherent to Wankel engine combustion chambers inhibits flame propagation. Two efficiency-enhancement technologies are introduced as disruptive solutions: (i) pre-chamber jet ignition and (ii) the two-stage rotary engine. These concepts overcome the traditional efficiency limitations and show that Wankel rotary engine design can be further enhanced for its role as a range extender in electrified vehicles.
Keywords
wankel rotary engines; thermal efficiency; large-eddy simulation; pre-chamber jet ignition; two-stage rotary engine
Subject
Engineering, Mechanical Engineering
Copyright: This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
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