What is the primary function of a torque converter in a heavy equipment transmission system?

The primary function of a torque converter in a heavy equipment transmission system is to multiply torque, especially at low speeds, and to provide a fluid coupling between the engine and the transmission. Torque is a twisting force that causes rotation. Heavy equipment, such as bulldozers and loaders, often needs high torque to overcome resistance when starting from a standstill or when working under heavy loads. A torque converter uses hydraulic fluid to transmit power from the engine to the transmission. It consists of three main components: an impeller, a turbine, and a stator. The impeller is connected to the engine and spins at engine speed. As the impeller spins, it throws hydraulic fluid outwards, towards the turbine. The turbine is connected to the transmission input shaft. The fluid from the impeller strikes the turbine blades, causing the turbine to rotate and transmit power to the transmission. The stator is located between the turbine and the impeller. It redirects the fluid flowing from the turbine back to the impeller, increasing the fluid's velocity and force. This redirection of fluid is what multiplies the torque. The torque multiplication is highest when the turbine is stationary or rotating slowly, such as when the equipment is starting from a standstill. As the turbine speed increases, the torque multiplication decreases. The torque converter also acts as a fluid coupling, which means it allows the engine to continue running even when the wheels are stopped. This prevents the engine from stalling and provides smooth acceleration. For example, when a bulldozer is pushing a heavy load, the torque converter allows the engine to maintain a constant speed while the tracks slow down or even stop momentarily. This provides the necessary torque to overcome the resistance and prevents the engine from stalling. Without a torque converter, heavy equipment would require a much larger engine to provide the necessary torque at low speeds, and it would be more difficult to operate smoothly and efficiently. While modern heavy equipment also utilize electronically controlled transmissions with lock-up clutches, the torque converter still fulfills its primary role of torque multiplication and fluid coupling.