what is a torque converter?
Torque converters are very special engine components, and their innards rarely see the light of day, when and if they do, they are still pretty hard to understand. Compared to other internal components of your vehicle, the torque converter looks like something out of a spaceship. Regardless of how this component looks or sounds, if you have an automatic transmission vehicle, you use this component daily.
If you have a basic understanding of manual transmission vehicles, you know that the engine connects to the transmission with a clutch. Without this connection, the vehicle could not come to a complete stop without killing the engine. However, automatic transmission vehicles do not have a clutch disc connecting the engine to the transmission; instead, they have a torque converter. Its physical appearance may seem minimal, but there's a lot going on inside.
The torque converter in your vehicle is the same as the clutch in a manual transmission vehicle. However, unlike a manual transmission vehicle, it uses a fluid to transmit power to the transmission, preventing your engine from stalling and allowing the transmission to shift.
Your torque converter explained
A torque converter is a doughnut-shaped internal engine component attached directly between the engine and the transmission. Inside the torque converter, there are two sets of curved blades, each facing the opposite direction. The space inside the torque converter is normally full of transmission fluid, which helps transfer the power generated by the engine to the transmission. Sounds strange, right? Not really! Your vehicle's engine drives one of the turbines also known as a paddlewheel, which pushes fluid over the turbine. The torque converter is efficient because its blades are precisely designed to maximize energy transmission by reducing heat build-up or turbulence.
A better way to understand how it works is to imagine two fans facing each other. When one fan plugs into the power supply (the motor), it will begin to move the second fan (the transmission). If the fan blades are the same size and weight, they will spin at the same speed. However, this is a gross simplification of how the torque converter works.
There are a few factors that allow the torque converter to be more efficient; this includes the stator, which helps it redirect the flow of transmission fluid to the impeller for improved efficiency.
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How does a torque converter work?
It's a little difficult to grasp the concept of how fluid can provide the power to move something as substantial as a vehicle. A pump provides torque control that works by sending fluid around the torque converter determined by crankshaft rotation. Inside the housing is a turbine that rotates as the pumped fluid contacts the turbine blades, which measures the amount of torque that reaches the transmission via the input shafts.
The torque converter housing connects to the flywheel, which rotates at the same rate as the crankshaft, in the turbine housing. The turbine or centrifugal pump effectively throws the transmission fluid into the turbine blades, which in turn turns or transmits torque into the transmission. The stator is the barrier that returns the fluid directly to the turbine rather than the pump, increasing the efficiency of the system.
When the vehicle is idling, the rate at which transmission fluid is pumped into the turbine is slow, which means that very little torque reaches the engine through the transmission. As the crankshaft turns faster with more throttle turning the flywheel, fluid is propelled faster from the pump to the turbine forcing the turbine to turn faster, allowing more torque through the transmission.
It is important to note that the inner workings of the torque converter are still somewhat mysterious. The basic mechanics may be understandable, but the complex calculations and underlying engineering are best understood by someone with an advanced knowledge of fluid mechanics.
Can a torque converter malfunction?
A torque converter can malfunction in a number of ways, some of which can be very dangerous. High levels of slippage will cause it to overheat, which will damage the elastomeric seals that help keep the transmission fluid in the converter. When the fluid begins to leak, it will stop working altogether.
It is also possible that the stator clutch will brake or lock up completely. When this happens, the inner and outer elements of the clutch will be permanently locked, resulting in energy inefficiency. If the stator breaks completely, it will rotate freely, interrupting vehicle power. When high pressure is created from the hot fluid moving inside the torque converter housing, it can become too high and cause it to swell or burst.
Getting information about your vehicle
Your vehicle's torque converter is an overlooked part of any vehicle. Most owners will never interact with this part in their entire driving life. However, it is the lifeblood of an automatic transmission and also a big part of fuel efficiency. Knowing how it works could help you know how to diagnose problems attributed to your transmission, saving time and repair costs.
Torque Converter, How does it work?