Torque converters are extraordinary engine components. Their insides are rarely seen, and even when you hold them in your hands, they are pretty tricky to figure out. A torque converter resembles a doughnut from outer space, but you use this part daily if you have an automatic transmission vehicle.
So, if you look at a manual transmission vehicle, the engine connects to a clutch that connects to the transmission. This connection enables the vehicle to come to a complete stop without stalling.
Vehicles with an automatic transmission, on the other hand, don’t have a clutch disc to connect the engine to the transmission. Instead, they have a torque converter. On the surface, it may seem unassuming, but inside, all sorts of mechanical magic happen.
An automatic vehicle’s torque converter does the same as a clutch in a vehicle with a manual transmission. However, it uses fluid to transmit power to the transmission to prevent your engine from stalling and allowing a transmission change.
How a torque converter works
A torque converter is directly attached between the engine and transmission. Inside the torque converter, two curved blades, each facing the opposite direction, make up the turbine. The space inside the filled with transmission fluid to help transfer the power generated from the engine to the transmission. The vehicle’s engine drives one of the impellers, pushing the fluid onto the turbine.
A pump assists with torque control by sending fluid around the torque converter determined by the crankshaft rotation. Within the torque converter housing, a turbine rotates as the pumped fluid comes into contact with its vanes. This helps to gauge the amount of torque that gets to the transmission through the input shafts.
The torque converter’s housing is bolted to the engine’s flywheel, so it turns at whatever speed the engine is running. Likewise, the fins that make up the torque converter pump are attached to the housing and turn at the same speed as the engine.
The pump inside a torque converter is a type of centrifugal pump. As it spins, the transmission fluid is flung to the outside. During this process, a vacuum is created that draws more transmission fluid to the centre.
Then, the transmission fluid enters the blades of the turbine, which is connected to the transmission. The turbine causes the transmission to spin, and your car moves.
The fluid exits the turbine at the centre, moving in a different direction than when it entered.
The stator sends the fluid returning from the turbine to the pump to improve the efficiency of the torque converter. The stator is positioned in the very centre of the torque converter and redirects the transmission fluid returning from the turbine before it hits the pump again.
The stator’s blade design almost completely reverses the direction of the transmission fluid. A one-way clutch inside the stator connects it to a fixed shaft in the transmission. As a result, the stator can only spin in the opposite direction to the transmission fluid, forcing the fluid to change direction as it hits the stator blades.
Benefits and drawbacks of torque converters
In addition to the critical job of allowing your car to come to a complete stop without killing the engine, a torque converter actually gives your car more power when you accelerate out of a stop.
At higher speeds, the transmission eventually moves at almost the same speed as the engine. Ideally, the transmission should move at precisely the same speed as the engine to avoid wasted power.
Contact Countrywide Gearbox Repairs today
Countrywide Gearbox Repairs specialise in quality repairs of gearboxes, clutches, torque converters and transmissions for heavy-duty trucks, tractors, forklifts, earth moving equipment, cranes, LHDs, graders and loaders, underground mining machinery, and LDVs. For more information about how we can assist with any torque converter issues, you may have, get in touch with our experienced technicians today.