Which type of gasoline engine employs a rotary design rather than pistons?

The rotary engine, also known as a Wankel engine, uniquely utilizes a triangular rotor that rotates within an epitrochoidal housing instead of employing the back-and-forth motion of pistons typical in conventional engines. This design allows for a compact engine structure with fewer moving parts, leading to a lighter-weight assembly compared to traditional piston engines. The rotary motion of the rotor serves to create different chambers that facilitate the intake, compression, power, and exhaust cycles in a continuous manner, contributing to smoother operation and a high power-to-weight ratio. This distinct operational mechanism sets the rotary engine apart from diesel, hybrid, and conventional piston engines, which rely on the linear motion of pistons to function.