Laser surface texturing of Wankel engine apex seals

Wankel rotary engines are used as power units in contemporary machines such as unmanned aerial vehicles and automobile range extenders due to their high-power density. A challenge of the engine architecture is the maintenance of an effective seal around each chamber while simultaneously minimising parasitic frictional losses. This paper investigates, experimentally, the suitability of laser surface texturing to reduce frictional losses at the apex seal-housing interfaces of Wankel engines. To inform the design of the laser surface texture features an analytical model is created to characterise the tribological properties of the apex seal-housing conjunction. The performance of the texture features is evaluated experimentally, and the results indicate that laser surface texture features can reduce frictional power loss by up to 30% at the apex seal-housing interface.