All about the Torque
Welcome back! Ready to learn some more about Automatic Transmissions? Good! But before we begin, as always, let’s do a quick recap & review some definitions.
Previously on Anthony’s Automotive Blog….
Last week, we learned more about the Clutch Pack and Band interact with the Planetary Gear System. If you wish to do a quick re-read of it, you can find it here. For the quick recap, keep going.
The Clutch Pack consists of a drum and a bunch of disks. It, and the Band, add an additional way to manipulate the Planetary Gear System; in particular, another way to lock one or more of the gears in place and give more shifting ability to the Automatic Transmission.
Now, let’s take a slight step back and look at the Torque Converter again (see our first blog here where we first talked about the good ole Torque Converter). Let’s add some new words to your automotive dictionary.
Our Growing Automotive Vocabulary
Here is a recap of some of the automotive words we listed last week just in case there is any lingering confusion. There are a couple of new additions as well.
Transmission – The mechanism by which power is transmitted from an engine to the wheels of a motor vehicle.
Torque Converter – A device that transmits or multiplies torque generated by an engine.
Gear – One of a set of toothed wheels that work together to alter the relation between the speed of a driving mechanism (such as the engine of a vehicle or the crank of a bicycle) and the speed of the driven parts (the wheels).
Automatic – A device or process that works by itself with little or no direct human control.
Automatic Transmission – An automotive transmission that can automatically change gears as the vehicle moves, freeing the driver from having to shift gears manually.
Clutch – A mechanism for connecting and disconnecting a vehicle engine from its transmission system.
Band – Something that binds, ties together, restrains, etc.; a strip or ring of wood, metal, rubber, etc. fastened around something to bind or tie it together.
Planetary Gear System – A gear system that consists of one or more planet gears (the gears in the middle area) that rotate or revolve around a sun gear (the gear in the center) and a ring gear (the gear on the outer edge).
Pump – Any of the various machines that force a liquid or gas into or through, or draw it out of, something, as by suction or pressure.
Turbine – An engine or motor driven by the pressure of steam, water, air, etc. against the curved vanes of a wheel or set of wheels fastened to a driving shaft.
Stator – A fixed part forming the pivot or housing for a revolving part, as in a motor, dynamo, etc..
Centrifugal – Moving or tending to move away from a center.
Shaft – A long, slender part or object.
It’s all about the Donuts…I mean Torque
The Torque Converter is a large round part that is mounted between the engine and the transmission. It is typically 10-15 inches in diameter. And it is actually comprised of three parts: the Pump, the Turbine and the Stator. The Torque Converter is typically mounted between the engine and the transmission, which makes sense, because you need it to interact with both.
The whole purpose of the Torque Converter is to keep your engine running when your vehicle is either in between shifting, is coming to a stop, or not moving at all.
You will find the following analogy all over the internet when people talk about torque conversion because it IS the perfect, simplest example of this concept. Go get two fans and put them facing each other. Go ahead and turn one of them on. You will notice that the blades of the second fan will start moving from the wind coming from the first fan. AND, if you let it go long enough, the spinning blades of the second fan will match the speed of the blades of the first fan.
Now, hold the blades on the second fan so that they don’t move. The first fan will continue spinning because it’s still on. You didn’t turn it off. You just stopped the second fan from spinning. This, my friends, is Torque Conversion.
Your car takes the above example and replaces the wind with transmission fluid. And the fans? They are the Pump, Turbine and Stator that is at our disposal in the Torque Converter. All three of these have fins on them to help them direct the flow of the fluid through the converter.
A Pump, A Turbine and a Stator walk into a bar….
The Pump is a centrifugal pump. When the engine is running, the transmission fluid is pulled into the pump and then pushed outward until it enters the blades of the Turbine, which – You Guessed it – starts turning.
The fluid continues to move around and will head back toward the center of the Turbine, at which point, it will encounter the Stator. The Stator is there to prevent the fluid from getting back to the Pump. When the fluid hits the Stator, it is actually pushed into the One Way Clutch which stops it from turning. When the Stator is not moving, then the fluid enters the Pump again.
You want this to happen because any fluid that hits the Pump instead of entering it, will actually slow your engine down and you’ll end up wasting power. When the fluid enters the Pump, it causes a torque increase, which is a way more efficient use of power.
Ideas for Next Week
Next week, I want to continue with the Torque Converter and look more closely at the One Way Clutch. I know I threw this word in the above paragraphs without giving you the definition. Come back next week and I promise I’ll clear that one up for you.
Until Next Time….