The torque converter is what makes automatic transmission in cars or trucks move. And while they’re an integral part of an automatic vehicle, many people don’t understand how they work. Read on to learn what a torque converter is and how it keeps you rolling down the road.
Before we get into the idea of a torque converter, let’s take a quick look at what torque is. In simplest terms, torque is the potential energy you create when you twist something up. The wind-up toys you used to play with as a kid and the cars that roll forward after you pull them back both work on torque force.
In cars, the turning of the engine’s crankshaft produces torque. This is what allows you to accelerate your car. The more torque your engine produces, the faster it goes.
The torque converter is what transmits that torque from the engine to a rotating driven load. In an automatic transmission car, the torque converter connects the power source to the load.
Torque converters are composed of five main components: the impeller, the turbine, the stator, a clutch, and the fluid. The stator is what makes a torque converter a torque converter; without the stator, it’s just the fluid coupling.
The impeller is a piece with tilted blades that look somewhat like a fan. This piece is turned mechanically by the engine. As it spins, the impeller pushes transmission fluid through its blades; the faster it goes, the faster the fluid moves.
When the fluid leaves the impeller, it moves into the turbine, a nearly identical bladed piece that sits opposite the impeller. The fluid hitting the angled blades of the turbine causes the turbine to begin turning, which turns the transmission shaft and pump in your car. The fluid is redirected through the center of the turbine, where it hits the impeller again.
This is where the stator comes in; the stator sits in the center of the torque converter. This is another series of fan type blades that are angled so that when the transmission fluid flows into them, it reverses direction again. The stator keeps the transmission fluid, which is turning in the opposite direction of the engine, from hitting the converter housing and slowing it down.
A torque converter also has a housing that is attached to the engine along with the impeller. Most torque converters also use a lock-up clutch that locks the impeller and the turbine together at high speeds to increase vehicle fuel efficiency.