DESIGNING AND MANUFACTURING OF A LIQUID PISTON ROTARY ENGINE, AND COMPARISON OF PERFORMANCE WITH WANKEL'S ROTARY

Abstract

Rotary engines, known for their high power-to-weight ratio, are offered as a compelling alternative to conventional engines. However, major drawbacks such as thermal inefficiency, high emissions, and limited durability are also exhibited. In this Capstone project, the Wankel engine, a classic rotary architecture, is compared with the LiquidPiston engine, a modern alternative employing the High-Efficiency Hybrid Cycle to address the Wankel’s limitations. The goal of this study was to assess whether modern cycle innovations can yield measurable improvements in efficiency and durability, and to determine the applicability of rapid prototyping for concept validation. Detailed 3D CAD models were developed and static simulations were conducted, but experimental tests using 3D-printed prototypes revealed critical assembly and material constraints that prevented rotor motion under compressor load. 3D modeling of both the engines was conducted, followed by computational evaluation of major performance factors such as thermal efficiency, output power, emission calculations, and structural lifespan. Experimental validations were then undertaken. Preliminary literature and simulation data suggest that the LiquidPiston engine is better than the Wankel design on all the metrics studied. A thorough comparative evaluation has been established to fill the research literature gap on the performance comparison of rotary engines.