UCLA

Conventional rotary engine designs are based on an epitrochoidal housing bore that is found by the path of the point at the rotor profile's apex. To seal the engine, the rotor apexes are replaced by spring-loaded apex seals that slide along the housing bore during rotation. The conventional designs are limited to the point-based epitrochoid housing profiles and cannot incorporate the profile of the apex seal. This dissertation presents the complete theory and algorithm of the deviation function (DF) method of rotary engine design. This method is based on conjugate pair design and generates new engine profiles from generating curves. The DF method of rotary engine design by apex seal profile is introduced and developed for generating new profile designs in which the housing profile conforms to the apex seal profile, for better sealing. The DF method of design by geometric parameters is developed to select profiles using the standard rotary engine geometry. Maximum theoretical compression ratio and swept area are two criteria that have a range of possible DF-designed profile solutions. For the apex seal design and selection process, a sealing index is defined and a multi-apex-sealing grid is developed to further improve apex sealing. The DF method of rotary engine design is extended to noncircular pitch curves, for generating more new profiles that incorporate a variable speed ratio between the rotor and main shaft.

By using the DF method, a larger variety of engine profiles is available to meet multiple design criteria and allow more flexibility in the design process. Some example deviation functions are provided for process illustration and design development. Engine profile designs and methods using circular pitch curves are developed using both arc-based and nonarc-based apex seal profiles. Engine profile designs with noncircular pitch curves are developed using the arc-based seal profile.