Your Automotive Vocabulary

In our replay from last week, I did not include any definitions for you. As we have gone on this journey, we have been adding words to your automotive vocabulary. You can always find the current list here.  But for ease of reading, here is the entire list in alphabetical order.

  • 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.
  • 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.
  • Centrifugal – Moving or tending to move away from a center.
  • Converter – A person or thing that causes a change in form, character or function.
  • Clutch – A mechanism for connecting and disconnecting a vehicle engine from its transmission system.
  • Driven Parts – The Wheels
  • Driveshaft – A rotating shaft that transmits torque in an engine.
  • Epicyclic – A circle whose center moves along the circumference of another, larger circle.
  • Flange – A projecting rim or collar on a wheel, pipe, rail, etc., to hold it in place, give it strength, guide it, or attach it to something else.
  • Gasket – A shaped piece or ring of rubber or other material sealing the junction between two surfaces in an engine or other device.
  • 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).
  • Hydraulic – Operated by the movement and force of liquid; specifically, operated by the pressure created when a liquid is forced through an aperture, tube, etc..
  • Input – The act of putting in; or, what is put in.
  • Manual – A thing operated or done by hand rather than automatically or electronically, in particular.
  • Manual Transmission – An automotive transmission consisting of a system of interlocking gear wheels and a lever that enables the driver to shift gears manually.
  • Neutral – A disengaged position of gears in which the engine is disconnected from the driven parts.
  • Oil – Any of various kinds of greasy, combustible substances obtained from animal, vegetable, and mineral sources; oils are liquid at ordinary temperatures and soluble in certain organic solvents, as ether, but not in water.
  • Output – The work done or amount produced by a person, machine, production line, manufacturing plant, etc., especially over a given period.
  • Pack – A number of similar or related persons or things.
  • Pipe – A long tube of clay, concrete, metal, wood, etc., for conveying water, gas, oil, etc. or for use in construction. Also, anything tubular in form.
  • Piston – A disk or short cylinder closely fitted in a hollow cylinder and moved back and forth by the pressure of a fluid so as to transmit reciprocating motion to the piston rod attached to it, or moved by the rod so as to exert pressure on the fluid.
  • 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.
  • Radiator – A device of tubes and fins, as in an automobile, through which circulating water passes to radiate superfluous heat and thus cool the engine.
  • Regulator – A mechanism for controlling or governing the movement of machinery, the flow of liquids, gases, electricity, steam, etc..
  • Seal – A device or substance that is used to join two things together to prevent them from coming apart or to prevent anything from passing between them.
  • Servo – This is short for Servomechanism OR Servomotor.
  • Servomechanism – An automatic control system in which the output is constantly or intermittently compared with the input through feedback so that the error or difference between the two quantities can be used to bring about the desired amount of control.
  • Servomotor – A device, as an electric motor, hydraulic piston, etc., that is controlled by an amplified signal from a command device of low power, as in a servomechanism.
  • Shaft – A long, slender part or object.
  • Solenoid – A coil of wire, usually wound in the form of a helix, that acts like a bar magnet when carrying a current: used in brakes, switches, relays, etc..
  • Soluble – That can be dissolved; able to pass into solution.
  • Solvent – A substance, usually liquid, that dissolves or can dissolve another substance.
  • Spline – A flat key or strip that fits into a groove or slot between parts.
  • Sprag – A device for preventing a vehicle from rolling backward on a grade.
  • Stator – A fixed part forming the pivot or housing for a revolving part, as in a motor, dynamo, etc..
  • Throttle – The valve that regulates the amount of fuel vapor entering an internal-combustion engine or controls the flow of steam in a steam line. This is also known as the Throttle Valve.
  • Torque – A twisting force that tends to cause rotation.
  • Torque Converter – A device that transmits or multiplies torque generated by an engine.
  • Transmission – The mechanism by which power is transmitted from an engine to the wheels of a motor vehicle.
  • Tube – A hollow cylinder or pipe of metal, glass, rubber, etc., usually long in proportion to its diameter, used for conveying fluids, etc..
  • 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.
  • Valve – Any device in a pipe or tube that permits a flow in one direction only, or regulates the flow of whatever is in the pipe, by means of a flap, lid, plug, etc. acting to open or block passage.

 

Thoughts for Next Week

Next week we will dive back into the transmission and take a look at the difference between what goes on with a non-computerized transmission. You will be surprised at the difference.

 

Until Next Time….

Anthony’s Automotive

One, Two, Three…Replay!

Welcome back! I know last time we said that we’d look at how the non-computerized transmissions work but we’re going to hold off on that. Instead, let’s review all that we have learned over the past several weeks. We want to make sure you have a good understanding of how the transmission works before we add any new data and concepts to this.

 

The Automatic Transmission

 

In this photo, you will see exactly what we’ve been talking about for the past several weeks. This is the side view of your car’s transmission. You can even see the Gear Shift attached. This photo gives a great perspective on how the transmission looks and where everything is placed in relation to each other.

Transmission with Gear Shift

Side view of transmission with the attached Gear Shift

Now…how does it work again?

You put your key in the ignition and you turn your car on. The engine is now running and the Torque Converter has been engaged. Transmission fluid is now pumping through your car’s transmission via the Pump, through the Turbine, into the Stator and into the One Way Clutch. This essentially keeps your engine running and keeps your car moving while its shifting gears, idling, etc..

When you shifted your Gear Shift into the Drive position, you have basically put it into First Gear and told your car that you want all the gears available for it to use while you are moving forward.

Now back to the One Way Clutch – the transmission fluid doesn’t just stop there. It keeps moving. Through a complex series of passages and tubes, the fluid moves into the Valve Body of your car’s transmission. And it does this only because it is under pressure the entire time.

This pressure is generated by the Oil Pump when you turn your engine on. It is connected to the torque converter which means it is connected to both the engine and the transmission. As long as there is sufficient oil located in the oil pan (on the bottom side of the transmission), it will create pressure and will allow the transmission fluid to flow through the transmission.

Now back to the Valve Body – transmission fluid is directed to the channels that lead to specific valves required to allow a gear shift to occur.

 

And how exactly does it know which channels to use?

 

In a computer controlled transmission, there are sensors that are used to capture lots of data related to your engine: brake pedal position, engine load (how ‘hard’ it’s working), engine speed, vehicle speed and many more. By compiling all this information, it can exactly pinpoint when a gear shift needs to occur. AND when it has properly identified that moment, it transmits to the Solenoid Packs in the transmission so that they can redirect the transmission fluid as needed to the correct clutch pack/band/servo to shift the gear.

Remember – a Solenoid Pack is simply a coiled wire that acts like a magnet when an electrical current is running through it and it can easily open and close valves.

 

In a Nutshell

You turn your car on. This causes the oil to create pressure that allows the transmission fluid to flow through the valve body, which selects the optimum gear for your car to be in at that specific moment. All you do is turn the car on, tell your car you want ALL the gears (putting in Drive) and put your foot on the gas pedal.

 

 

Until Next Time….

 Anthony’s Automotive

In a Clutch

Welcome back! Time to find out exactly what the One Way Clutch is that I mentioned last post. But before that, like always, time for a quick recap & review some definitions.

 

Previously on Anthony’s Automotive Blog….

 

Last week, we dived a little deeper into what is exactly involved with the Torque Converter and why you have one in the first place. Want to do a quick re-read? You can find it here.  For the recap, keep reading.

 

The Torque Converter can be found mounted between the engine and the transmission. It is made up of 3 different parts: the pump, the turbine and the stator. And its whole purpose for being is to make sure your engine keeps running when it is shifting between gears, coming to a stop or is not moving at all, aka idling.

 

There is one word added to this week’s vocabulary list: Sprag. You can find its definition at the bottom of the list. We’ve added a lot of words to your automotive dictionary these past couple of weeks. So much so that I am now going to start narrowing it down to just specific terms that are in relation to the week’s topic only. You can find our entire and current automotive dictionary here. Feel free to save its link so that you can find it again in case we use a word that happens to not be on this week’s list.

 

Our Growing Automotive Vocabulary

 

Here are the related words for this week’s topic. Enjoy expanding your vocabulary.

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..

Sprag – A device for preventing a vehicle from rolling backward on a grade.

 

Sprag_one-way_bearing_labeled

 

You Got Sprag….

 

A One Way Clutch is also known as a Sprag Clutch. The definition listed above is the one that is listed in the Webster’s Dictionary that I like to reference. There is another definition of Sprag that could be listed here. It is this:

 

            A simple brake on a vehicle, especially a stout stick or bar inserted between the spokes of a wheel to check its motion.

 

It is definitely a beefier definition than the one listed in the dictionary and it better describes the function of a One Way Clutch. It allows a part to move in one direction but not in the opposite direction.

An easier way to think of how a One Way Clutch works is to think of how a bicycle works. If you push the pedals in a forward motion, it moves the bike. But if you try to move it backwards, most bikes won’t. The pedals move freely but the wheels of the bike don’t. Most bikes do this. In fact, I remember many times as a kid when going downhill, we’d like to try to spin the pedals backwards fast and then stick our feet out while we coasted. Fun times!

Now let’s do that with your car. Start it up. Put your hand on the shifter and drop it into Drive. Push your foot on the gas pedal and start moving. You are technically in first gear and you are moving. Now, lift your foot off the gas. Does your car instantly stop moving? No! It’s kind of like you are coasting. Now put your foot back on the gas and you find yourself moving again. Take your foot off the gas again and yep – you are back to ‘coasting’. This is the One Way Clutch in action.

In First Gear while in Drive is where you will typically experience the One Way Clutch. The same thing happens when you have your car in Neutral, which is like you have ‘no gear’ engaged but the engine is still running. And speaking of Neutral….

 

gears of an automatic

 

Low Gear, First Gear, Neutral, Reverse – Just Drive!

 

How many gears are there exactly that you can choose to have an automatic transmission in OR exactly what is this alphabet soup on my shifter? Typically you will find what is in the picture above: P R N D 2 L  or   P R N D 2 1

P is for Park. This is when no gear has been selected and the gears have been locked to stop the vehicle from moving.

R is for Reverse. This is when the Reverse gear has been selected and will cause the vehicle to move backwards.

N is for Neutral. This is when no gear has been selected but the gears have NOT been locked and means the vehicle can and/or will move. You can push it and it will move. If you are on any kind of slope, it will roll all on its own. Neutral and Hills do not mix!

D is for Drive. This is your preferred choice, especially if you want to move. What Drive means is that all the gears are available for your car’s use when propelling the car forward. This means the progression from first gear to second gear to third gear to fourth gear and beyond will be done as you continue to accelerate.

2 is for Second Gear. This is when you limit the gear selection. In this setting, you have made only First and Second Gears available for your car to use.

L or 1 is for Low/First Gear. Just like the Second Gear setting except you have limited the gear selection to First Gear only.

 

You may see more letters or numbers than what is listed above. If it’s a number, then that typically refers to the highest gear that you are making available for your vehicle to use. If there are any specific letters that you’ve seen that you have a question on, comment or shoot us an email. We’d be happy to clear up any confusion for you.

 

Until Next Time….

 Anthony

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.

 

bd-torque-converter

 

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.

torque converter

 

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….

 Anthony’s Automotive

 

With a Clutch and a Band

Welcome back! We’re still on our journey learning about Transmissions – in particular, the Automatic Transmission. As always before we lift the hood, let’s do a quick recap & review some definitions.

 

Previously on Anthony’s Automotive Blog….

 

Last week, we talked about automatic transmissions. If you wish to do a quick re-read of it, you can find it here. For the quick recap, keep going.

 

The Planetary Gear System is what drives the Automatic Transmission vehicle. This system consists of the Ring Gear, the Sun Gear and the Planetary Gears (one or more) that rotate in between the first two. It is the combination of the locking and unlocking of one or more of these gears that allows the car to shift gears.

 

Now, let’s add the Clutch Pack and Band to this Gear System and really get moving. But first, let’s make sure you understand the lingo that we use.

 

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).

Hydraulic – Operated by the movement and force of liquid; specifically, operated by the pressure created when a liquid is forced through an aperture, tube, etc..

Input – The act of putting in; or, what is put in

Output – The work done or amount produced by a person, machine, production line, manufacturing plant, etc., especially over a given period.

Shaft – A long, slender part or object.

Pack – A number of similar or related person or things.

Spline – A flat key or strip that fits into a groove or slot between parts.

Piston – A disk or short cylinder closely fitted in a hollow cylinder and moved back and forth by the pressure of a fluid so as to transmit reciprocating motion to the piston rod attached to it, or moved by the rod so as to exert pressure on the fluid.

 

The Planetary Gear System continued….

 

Last week I had included a Side View image of the Planetary Gear System. Let me include it again and quickly give thanks to the people at www.carparts.com for this image. It is the simplest image that I could find for this lovely and complicated system on the great wide web.

 

planetary gear system

 

You can see the Input Shaft that is connected to the Ring Gear, as well as the Output Shaft that is connected to the Planetary Gears. What I want you to notice is that the Planetary Gears are also connected with the Clutch Pack. This is at the top and bottom of the image. The drum which houses the entire Clutch Pack is connected to the Sun Gear. So you have two parts of the Clutch Pack connected to two of the different gears.

On the outside of this whole unit, is the Band. The purpose of the Band is to tighten (and loosen) around the drum. This is another way to be able to lock the Sun Gear in place. When the Band is tightened, the Sun Gear cannot move. Or, with the assistance of the Clutch Pack, the Band, while tightened, will make the Sun Gear move in conjunction with the Planetary Gears.

 

Exactly what IS the Clutch Pack

 

I’m glad you asked that. The clutch pack consists of a drum and a bunch of disks. Now, these disks consist of two different types that are alternated as they are put in the drum. One half of these disks have splines on the outside of the disk that are designed to fit along groves that are on the inside of the drum. The other have splines on the inside of the disk that fit in the groves that are in the joining center part of the drum. In this Clutch Pack, there is a piston that, when activated by oil pressure, squeezes the disks together so they all turn as one. Which, in turn, will turn with whatever gears needed to shift the car into a different gear.

multiple-disk-clutch-pack

 

Ideas for Next Week

 

We’ve talked about the Planetary Gear System and all its parts and pieces. We have now added the new layers to this of the Clutch Pack and the Band that wraps around the outside. So, I think it is time for us to go back to where we started this whole journey and revisit Torque Conversion. You now understand the parts involved in this. So, next week, let’s really get into the nitty gritty of Torque Conversion.

 

Final Thought

 

I had a question last week of “where do I get my definitions?” Good ole…..

 

webster dictionary

 

Until Next Time….

 Anthony’s Automotive

There’s a planet IN my car???

Welcome back! It’s time to continue our look into the nooks and crannies of Transmissions. But before we lift the hood, let’s do a quick recap & review some definitions.

 

Previously on Anthony’s Automotive Blog….

 

Last week, we talked about automatic transmissions. If you wish to do a quick re-read of it, you can find it here. For the quick recap, keep on reading.

The automatic transmission system of a car works by using a series of gears that lock and unlock to shift them up or down in gear. This series of gears is called the Planetary Gear System and is comprised of the Ring Gear, The Planetary Gears and the Sun Gear. They rotate and revolve around each other and work together. It is the combination of locking one or two of these gears with the second and/or third being free that initiates the gear shift in the car.

planetary gear set

 

Last week, I barely scraped the grime off the surface of these gears and how they work. This week? Grab your rag and let’s get ALL the grime off them this time. Let’s make them shine!

 

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.

Epicyclic – A circle whose center moves along the circumference of another, larger circle.

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).

Hydraulic – Operated by the movement and force of liquid; specifically, operated by the pressure created when a liquid is forced through an aperture, tube, etc..

Input – The act of putting in; or, what is put in

Output – The work done or amount produced by a person, machine, production line, manufacturing plant, etc., especially over a given period.

Shaft – A long, slender part or object.

 

The Planetary Gear System

 

As mentioned before, the Planetary Gear System is comprised of three parts: the Ring Gear, the Planetary Gears and the Sun Gear. The Ring Gear is located on the outer edge. The Planetary Gears (which typically number two or more) are in the middle area and are mounted on a carrier or plate. The Sun Gear is located in the very center. The Planetary Gears rotate around the Sun Gear in the center and the Ring Gear along the outside.

How this system works is by moving one or more of these parts, while keeping one or more locked or still. Here’s an example that should really break this down for you to help you see what I’m talking about.

planetary gear system

 

Let’s say the Ring Gear is connected to the Input Shaft that is coming in from the engine and the Planetary Gear Carrier is connected to the Output Shaft, which is connected to the wheels. Now, in this example, let’s lock the Sun Gear in place so that it can’t move. As we turn the Ring Gear, the Planetary Gears will move in the same direction along the locked Sun Gear. This causes the Planetary Gear Carrier to turn the Output Shaft. This means that the Input Shaft and the Output Shaft are moving in the same direction. BUT, the Output Shaft is moving at a slower speed. Remember that the Input Shaft is connected to the Ring Gear and the Output Shaft is connected to the Planetary Gear Carrier? So the wheels are moving slower than the power of the engine. This is a car that is in First Gear.

Still with me? Good!

Now, let’s unlock the Sun Gear and lock the other two – the Ring Gear and the Planetary Gears. By doing this, all three of these will turn together as one. You now have the Input Shaft (power from the engine) and the Output Shaft (the wheels) turning at the same speed. This is a car that is in Third Gear or higher.

Makes sense right? Now we’re moving!

Finally, let’s lock the Planetary Gears and leave the Ring Gear and Sun Gear unlocked. By locking the Planetary Gears, you lock the Planetary Gear Carrier, which is connected to what again? The Output Shaft (the wheels). You give some power to the Ring Gear (aka the Input Shaft). This causes the Sun Gear to turn. But it’s going to turn in the opposite direction. And this means?

You guessed it! This is a car going in Reverse.

 

Food for Thought

 

There are many, many combinations that are possible when you use two or more planetary gears. They can be connected in various ways and provide many different forward speeds and reverse. There are some very clever gear arrangements that you will find in today’s modern automatic transmissions.

 

8 speed chevrolet corvette

 

Nowadays we have four-, five-, six-, seven and even eight-speed vehicles! Now that you know what a first and third gear looks like (Side Note – you CAN substitute the word ‘speed’ for ‘gear’ here to help), imagine trying to understand the combinations that these eight-speed cars must go through as they shift from first gear to their top gear as they head on down the highway. Talk about being complex! It is no surprise that we now have computers in today’s cars.

 

Ideas for Next Week

 

I feel that you should now have a good idea of how the gear system works in an Automatic Transmission. Next week, I’m going to build on that and we are going to add another level to this Planetary Gear System and expand your automotive knowledge a little further by talking about clutches and bands.

 

Until then,

Anthony’s Automotive

 

 

 

 

All about the Valves

Welcome back! This week we’re still on the topic of Transmissions. But this time, let’s get a little more technical know-how under your belts. But before we jump right in, let’s do a quick recap & review some definitions.

 

Previously on Anthony’s Automotive Blog….

 

Last week, we talked about just the basics when it comes to transmissions. If you wish to do a quick re-read of it, you can find it here. For a quick recap, keep reading.

Basically, your car’s transmission is what keeps it moving. They come in two flavors: Automatic or Manual (aka Stick Shift). Automatic transmissions require little to no interaction from the driver, while Manual transmissions require 100% interaction from the driver. Your transmission needs a special fluid to keep all of its parts working together. We also touched on some common problems that can occur & how to tell if it’s about to die.

gearshift

 

We also covered some basic definitions of various automotive-speak words that you could understand exactly what it was that I was saying. Let me recap a couple of those words here just in case. I will also add some new ones, as they do pertain to this week’s particular topic.

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.

Manual – A thing operated or done by hand rather than automatically or electronically, in particular.

Manual Transmission – An automotive transmission consisting of a system of interlocking gear wheels and a lever that enables the driver to shift gears manually.

Neutral – A disengaged position of gears in which the engine is disconnected from the driven parts.

Clutch – A mechanism for connecting and disconnecting a vehicle engine from its transmission system.

Epicyclic – A circle whose center moves along the circumference of another, larger circle.

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).

Hydraulic – Operated by the movement and force of liquid; specifically, operated by the pressure created when a liquid is forced through an aperture, tube, etc..

 

The Nuts and Bolts of an Automatic Transmission

 

As you recall, an automatic transmission is the type of transmission that requires little to no interaction from the driver (outside of putting your foot on the gas pedal that is) in order to work. But it is so much more complex than you think.

An automatic transmission system works by utilizing a series of gears that lock and unlock in order to change the gears of the vehicle. The transmission also uses a torque converter instead of a clutch to disconnect the transmission from the engine when the car needs to come to a stop.

The series of gears used actually have their own name. They are referred to as the Planetary Gear System (or Gear Set). The system has three main parts: the Ring Gear, the Planetary Gears and the Sun Gear. The Ring Gear is on the outer edge. The Planetary Gears are in the middle area (usually mounted to a carrier or plate). The Sun Gear is in the very center. The Planetary Gears rotate and revolve around the Sun Gear in the center and the Ring Gear on the outer edge.

 

planetary gear set

 

This system works by moving two of these parts, while keeping the third one still. By doing this, it can transmit the torque created by the engine to the wheels of the car, which, in turn, makes it move.

In addition to the above gear set, you also have what is called the Valve Body. It is what allows the automatic transmission of your car to smoothly shift gears as you are driving down the road. It is a hydraulic system that uses a pump to bring transmission fluid into the valve body. It then directs the fluid through a maze of channels and valves that, in turn, activate whatever gears are needed to shift to.

This maze is quite intricate and specialized. For example, if the car needs to shift from second to third gear, the transmission fluid needs to flow through the channels to the specific valve that is for that function. This valve is often called the 2-3 valve. And oddly enough, there is a specific valve for shifting from third back to second and it’s commonly called the 3-2 valve. In this system, there is a valve for everything!

 

Food for Thought

 

I hope you were able to learn a little more this week about exactly how an Automatic Transmission works. In a nutshell, fluid is pumped through the system and through a specific valve which tells the vehicle which gear it needs to shift to.

Next week, we’ll continue to learn more about how an Automatic Transmission works. In truth, we’ve just begun to scratch the surface.

Until then, I’ll leave you with something to think about. We’ve all seen those big semi trucks that are always slow to start moving and we all curse and moan when we get stuck behind them at a stoplight. They typically have anywhere from 12 to 18 gears that their engine has to shift through to get moving. Just imagine the number of valves that transmission would need in order to shift up and down all of those gears IF they were an automatic transmission. How big would that engine be??!!??

 

Until next time,

Anthony’s Automotive