Hexa-Wankel

A Geometric and Thermodynamic Hypothesis for a Six-Apex Rotary Engine with Dual-Zone Sequential Combustion

Abstract

This paper formulates the Hexa-Wankel as a theoretical design hypothesis for a six- apex rotary engine intended to preserve Wankel-like compactness while improving the determinacy of thermal and sealing conditions. The proposed architecture is not a flat hexagonal housing and not two triangular Wankel engines mechanically joined together. It is defined as a single convex six-apex rotor operating within a Wankel-like five-lobe baseline housing, with two housing-fixed combustion regions arranged as dual-zone sequential combustion. The intuitive process is therefore (1, 2, 3) + (4, 5, 6): intake, compression– ignition–expansion, exhaust, followed by a second intake, compression–ignition–expansion, exhaust sequence. The total fuel energy is not doubled, but divided into two pulses, QR+QL=Qpair withQR≃QL≃Qpair/2.

The paper derives the kinematic closure for an N-apex rotor, the six-apex/five-lobe gear law, the envelope regularity condition, swept-volume scaling, friction and leakage thresholds, Fourier thermal-harmonic balancing, the torque-kernel condition Ki(θs) = dVi/ dθs > 0, and gas-exchange constraints. It then reports a first-order two-dimensional kinematic validation: numerical chamber-volume computation gives Vd = 35.786cc per chamber in the baseline model, while an added clearance volume of 3.714cc represents a target compression ratio near r = 10.5. A subsequent torque-kernel validation identifies positive- expansion windows in the right and left combustion zones. Finally, an idealised zero- dimensional indicated-work model using unsmoothed clearance-corrected chamber volume, finite-duration Wiebe heat release, and W = 􏰈 p dV yields positive indicated work for the dual-pulse pair: WH = 120.05 J, ideal indicated efficiency 53.18%, pmax = 81.14 bar, and IMEP = 20.23bar under the stated no-wall-loss assumptions. A fair equivalent- displacement single-pulse control gives essentially the same ideal work and pressure, while the dual-pulse phase model reduces the theoretical torque-ripple index from 4.02 to 2.74. The strongest supported claim is therefore not guaranteed brake-efficiency superiority, but positive indicated work with redistributed torque loading and a more periodic thermal- sealing environment. The concept remains falsifiable and incomplete until conjugate 3D geometry, port timing, wall heat transfer, CFD, FEA, seal dynamics, and dynamometer validation are performed.