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Research Paper | Energy Engineering | Canada | Volume 11 Issue 7, July 2022 | Rating: 4.3 / 10
Quasiturbine High Power Density Pump-Expander-Engine with Displacement Exceeding External Device Volume for Light and Compact High Torque Applications
Gilles Saint-Hilaire [3] | Roxan Saint-Hilaire [3] | Ylian Saint-Hilaire [3] | Francoise Saint-Hilaire [3]
Abstract: There are numerous positive Displacement engine designs, among them the Piston engine, all looking for improvement in term of power density. The «total Displacement ratio over external engine volume is generally much less than 1, and needs to be increased to make lighter and more compact powerful engine. The Quasiturbine (QT) is a fairly recent rotary engine design with unique characteristics as pump, expander and internal combustion engine, where the timing for a framework contribution is appropriate. Each of the QTrotor 4 pivoting-blades executes 4 strokes, for a total of 16 strokes per rotation (as does the Piston (8-cylinders) in 1 rotation). Strong similitudes in engine management are shown with the Piston (8-cylinders) in term of strokes number; shaft RPM, torque, power, intake-strokes and total Displacement. In the context of positive Displacement devices, the QTdual circuits (2-strokes cycle) for pumps and expanders, the QT 2-strokes IC engine, as well as the QT (4-strokes, 2 rotations), all match (interchangeable) with the corresponding mode Piston (8-cylinders) device of equal stroke volume and total Displacement. The Quasiturbine can typically be 3 to 5 times more compact and lighter than the Piston of equivalent power at moderate RPM, while suppressing the need for step down gearbox in some applications. Current QT expander QTL (60 psi and 500 RPM) has a volume Displacement ratio over its external device volume (excluding ports and thin covers) of 0, 62 to 0, 85, while future optimized QT design would reach a theoretical volume Displacement ratio well over unity of 1, 2 to 1, 6, while doubling the relative power output as well, with no stator external volume increase. Criteria for optimum QT Displacement design are given in term of stator eccentricity and confinement profile. A statoroptimum configuration is presented among solutions that can involve different pivoting-blade and differential designs. Such a high-power density device still allows for high compression capability, efficiency, low RPM, and high torque (reduced gearbox?) for light and compact applications, including airplane engine. In the engine world, power density, high torque, low-cost manufacturing, and durability through perfectly balanced design are characteristics in demand, especially if sustainable locally and not high-tech dependent. The Quasiturbine is a step in that direction, at a time where hydrogen and synthetic fuels offer new perspectives. Not only a Piston8 (8-cylinders) in different modes can be substituted (interchangeable) with a single Quasiturbine of equal volume Displacement, but the QT total volume Displacement ratio could exceed unity.
Keywords: Quasiturbine, Rotary engine, Steam engine, Air engine, Rotary pump, Rotaty expander, High engine power density, Engine displacement, Light and compact engine
Edition: Volume 11 Issue 7, July 2022,
Pages: 330 - 345