A system employing a belt and pulley arrangement to transmit and modify torque between a power source and a driven load functions similarly to a fluid-based torque converter. This mechanism allows for variations in speed and torque ratios, effectively decoupling the engine speed from the load speed. A common example can be found in continuously variable transmissions (CVTs) used in various vehicles, including scooters, snowmobiles, and some automobiles.
The ability to dynamically adjust the torque ratio provides several advantages. It allows engines to operate at their most efficient speed range, leading to improved fuel economy and reduced emissions. Furthermore, this system provides smooth and seamless power delivery, enhancing vehicle drivability and performance, particularly under varying load conditions. Historically, belt-based systems have offered a lighter and potentially more cost-effective alternative to traditional hydraulic torque converters, particularly in applications where size and weight are critical factors.