Another car enthusiast here. I already appreciated the Prius, not for being an enthusiasts car, but for being an extremely reliable and quite comfortable runabout. Now I see how it works, and how advanced yet simple it actually is, I'm starting to see this car somewhat as an enthusiasts vehicle :-)
Fairly reliable, this CVT has its issues too. Overheating, slipping, lurching or jumping. It’s vulnerable for issues as any CVT. I do like Toyota’s and their reliability but they do have issues. Just poke around on google and there are groups who have complaints about this costly CVT
@@jeffsond lol, I don't know what you're on about - technically it isn't even a CVT :) only issue I hear that comes up regularly is the cooling system failing (and resulting issues after continued driving without appropriate cooling)
This car is loved by places and countries that have remote driving area and poor service distribution, as it is much reliable than conventional cars transmission and engine is, also, very robust for those markets. Because, most of the time cars do not drive fast long enough and have to slow down or break often, and accelerate again. Up and down hill offer good petrol saving, and engines do not overheat as much.
I heard that the fuel injection begins only after the engine has been spun to operating rpm by MG1. That explains why the Prius has very clean emission despite the frequent engine start and stop. In regular cars, the starter motor only turns the pistons to proper firing positions, the first few burnings may not be clean when the engine is not yet in ideal rpm.
Hi, thank you. You are absolutely correct regarding reverse. I realized my error after shooting the video, but nobody ever said anything until you. What I should have said is that MG1 will spin the opposite direction of MG2 in reverse because the planet carrier is stopped with the engine off. This allows MG1 to start the engine if necessary (which mine usually does upon cold startup) while backing up.
I recently bought my first hybrid, a 2025 Honda Civic. So I started watching these WeberAuto videos and I have to say that Professor Kelley has become a person I admire greatly for the detailed and precise work he has done to not only analyze these systems but also create these presentations for all of us to benefit from. I see that he is wheelchair bound now but it has not slowed him down one bit. He is an inspiration and I humbly say thank you sir.
As a car the Prius has many faults which prevent it from being an automobile for enthusiasts. I used to belong in this camp, until I've recently driven a Prius C. After driving it and doing the research behind the technology (and especially the eCVT), you have to be amazed that Toyota figured out how to use a single planetary gearset so efficiently before anybody else did and made the hybrid system blend EV & gas power so well. Well done on the explanation!
Trades46 My understanding is that the Power-Split Device ("PSD") was originally patented by a group of California inventors. Toyota made it work though, kinda analogous with the Wankel engine having been invented a long time earlier, but Mazda made it really work.
I have a Toyota Aqua (prius c) and I see nothing in it that prevents it from being an enthusiastic vehicle. There’s nothing inherent with a PSD Hybrid that stops you from driving, racing, or having fun with it. I’m curious what you used to think those “inherent faults” are other than “cars that were designed specifically to sacrifice performance for efficiency don’t have as much performance as cars that do the opposite”. Big surprise.
Toyota’s Prius holds a well-deserved place in the history of great technical accomplishments. Ingenious, groundbreaking, bold, and most amazingly, a smash sales success. Kudos to Toyota.
A very nice and clear explanation on the Toyota Hybrid drive system, and unusually accurate as well - Very nicely done. My only point would be that MG1 never drives the car. When going backwards it is always MG2 that provides the motive force (just like when going forwards) Whilst driving backwards MG2 is the motor and MG1 will be freewheeling, unless the engine needs to run in which case MG1 is a generator charging the battery (Providing the electricity for MG2 to drive the car)
This is one of the best videos explaining how the ECVT works. It is amazing how Toyota innovated such a simple yet effective solution using only a planetary gearbox. Thanks for the excellent explanation.
whoa... hard to believe this is a 12 year old video. I'm not a mechanical engineer in any shape or form, but was able to follow along and understand your every point. Great information, and extremely well presented. Thank you for this!
I am loving these Hybrid cars. I recently purchased a used 2008 Prius and I am fascinated with the technology that goes into these cars. The Prii are also immensely reliable. You tend to see many in the road sitting pretty at 200, 300 and 400k miles on them.
I've always chosen to drive manual-transmission cars, because I like their mechanical simplicity compared to automatic transmissions. I'd assumed that hybrids were even more complex, so I've never been interested in them. However, after looking at this video, and the excellent companion video of the 3rd Generation eCVT, I'm impressed by the overall efficiency and simplicity of the Toyota concept. I'll definitely consider a Toyota hybrid for my next car.
Late reply but these transmissions are the most robust and reliable I have ever experienced. Never had any issues with them, even well into old age 450,000kms and beyond. The most I've seen is some leaky seals so some splash lubricant can leak but the actual mechanism used in the first and second gens are phenomenal. Can't say the same for brand new junk 😂 but our first gen Toyota Highlander is an absolutely outstanding vehicle
There is an incredibly detailed and well done software available to the public called Hybrid Assistant that allows you, in real time to monitor every possible facet of MG1, MG2, and everything from high voltage battery real time charge and decharge, temps, all combustion gauge values even high voltage fan speed. Having these values real time is crucial if not just for the fact that only a Toyota hybrid is monitoring that many systems, and just as a space shuttle launch command - after a while you start to understand the personality of your vehicle so you can understand what is going on with her before a possible incident or how to achieve performance or efficiency. I love driving my hybrid systems with all that real time data You need a good OBDII sending unit and you’re good.
Great video. I wish the audio was a bit clearer and there was some close-up shots. But still one of the best explanation videos out there. I've seen diagrams of how this stuff works, but seeing the actual parts really makes a big difference. I actually always imagined many of those parts being quite a bit larger than they really are, especially the planetary gear set. MG1 and MG2 look small, but I think because we're not seeing them with the stators around them.
@sosarres 2. (Vehicle moving) Rotate MG2 (ring gear), MG1 rotating more than 2.6 times faster than MG2 (sun gear), the crankshaft (planet carrier) will rotate to start the engine. There is also a time when the crankshaft will be rotated but the engine is not intended to start: Full battery charge, decelerating down a long steep hill, regenerative power has to go somewhere so it is used to rotate the crankshaft with MG1 to dissipate the additional energy.
So this is how the sequential parallel system works. I love the simplicity of it as the ring, sun, and planetary gears are the only mechanically moving parts in the transmission, and by simplicity adjusting power/drag to MG1 you effectively control the entire ratio range. It's also ultra efficient as when MG1 is driving the sun gear for a high wheel speed, that energy ends up at the wheels too outside of friction losses, and when MG1, MG2, and the combustion engine are RPM matched, the entire transmission moves as one part, and as such there's no friction from the meshed gears
Lecturer is brilliant. Explains a complex scenario in a very logical and enjoyable manner. I am of the age where Japanese designs in the early days were mostly poor copies of European ideas, which is contradictory to todays Toyota engineers have shown by this drive system to be creative and innovative.
I thoroughly enjoyed this video, my hat off to you sir, you're a remarkable teacher with a natural ability to impart information. As with most engineering systems, the fundamentals are straight forward when you understand how they work as a system. Explaining these fundamentals in an easy to understand way is often not so straight forward, again, great job sir. #Respect.
Thank you for this presentation. This vehicle is not completely a independent novel concept since it incorporates a lot of technology that may be familiar to other transportation modes such as freight trains. Having said that, it is undoubtedly the pinnacle of Toyota's engineering with conventional and electrical propulsion . I also get lost in the details of wheel and tire technology used, also weight distribution and energy use and conservation. Your poise as a teacher is also reassuring
This video gives the best explanation for how the Toyota eCVT works. I now think I understand the concept. Well done sir and hats off to Toyota for creating this beautiful y engineered system!
@luvmygooose 1. The P112 transaxle input damper (looks like a clutch disk) absorbs the shock that accompanies transmission of the drive force from the engine. It is permanently applied. If it slips, a P0A90 DTC will trigger for a transaxle input malfunction. 2. The vehicle can move on Motor-Generator 2 (MG2) power alone (up to near 37 MPH) or a combination of both the MG2 (driving the ring gear) and the Internal Combustion Engine (ICE) driving the planet carrier (at all vehicle speeds).
I'm on my 3rd Prius, 7 years ago I wouldn't even look at a Prius, but it's a great car for reliability I put 320k on my 2nd one with no problems at all NOTHING BROKE DOWN. I've always wondered how the assembly worked. So a big thank you for the video don't worry if you are considering buying a Prius don't worry great car for reliability
Transaxle damper has internal springs to sort out the vibration when the engine starts and stops, to reduce the shockwave through the drive train. The Friction material the there in case of a catastrophic failure or the engine at speed to make sure that the roads wheels don’t lock or destroy MG1 by over revving.
Wow! This video is old but gold. Btw, you missed the part in which the motor needs to operate in order to discharge the battery to prevent it from being overcharged.
just want to say i watch a lot of videos, but your videos are the best i ever saw. i am a mechanic myself and love to check your videos. thanks a lot , would like to your workshop one day,i am in south africa, thanks again.
It is really smart and very small. I was expecting the MG1 and MG2 be much bigger, and closer in size. The size of the planetary gear set is also small. Amazing.
Best dive into the Prius gen 2 I've seen. Running 2( 2008 w/ 220,000 and 2007 w/ 290,000 ) gen. 2's currently. Love them but '07 needs at least one new batt. cell( death triangle getting consistent). Even a Prius needs some maintenance!
@sosarres Hi, you are correct when you state that the engine's crankshaft will rotate at the same speed as MG1 (when MG1 and MG2 are rotating at the same speed as each other); however, this is not how the engine normally is started. The most common ways the engine can be started are: 1. (Vehicle stopped) MG2 stopped (ring gear), rotate MG1 (sun gear), the crankshaft (planet carrier) will rotate to start the engine.
My favorite part about the Toyota hybrid platform is actually the transmission... what drew me to Toyota was their hybrid platform. My whole family owns a hybrid from Toyota now because of how reliable and efficient they are (five vehicles now... I'm on my second hybrid, nothing wrong with the first one, just wanted a new car... 2020 Corolla hybrid). Love the buttery smooth shifts even at 100k miles. I hate autos with fixed gears, shifts thumping, sticking, hesitating, so on and so forth... especially with age.
Outstanding lesson!!! I have a 2022 Tundra hybrid on order with a 1.87 kWh battery and now I know the basics and understand MG1, MG2, planetary gears, sun gears, etc. I find it fascinating that an “old school” starter and alternator are not required with a Toyota hybrid system.
@supermachoman222 Hi, I appreciate your comments, but they are incorrect. During electric only mode MG2 propels the vehicle and the engine's crankshaft is stationary; there is no piston movement. This mode is only used up through a maximum of 40 mph. Afterwards, MG1 acts like a starter motor and does start the engine to contribute power to MG2 and to slow down MG1. This is very efficient resulting in the best city fuel economy of any hybrid-electric on the road.
I'm confused. Did I miss the part where he talks about the variation of the transmission? I want to know how the car do basically do whatever speed at 2k engine rpm.
The speed of the output (MG2) is controlled by the ratio between the engine and MG1. To speed up MG2 while keeping the engine constant MG1 has to slow down, and vis versa.
Awesome video! I had know idea my lexus hybrid system so complex...and I now understand it. I always thought it was just a electric motor that replaced the flywheel or something like that. Thanks!
Amazing explanation of the eCVT operation! Great Work Mr. Kelley, please keep making more videos like this one. Also, this video ends abruptly. Could you kindly explain what happens next? that is what happens at a much higher vehicle speed? how does both ICE and MG act in parallel mode via the eCVT? Thanks
I have a Prius 2 for 12 years now. Just great to drive and so economical. When you reach your destination in Prius, you would like more road ahead. Thanks WeberAuto J'ai une Prius 2 depuis 12 ans à présent. Juste génial à conduire et tellement économique. Lorsque vous atteignez votre destination en Prius, vous voudriez que le route continue. Merci WeberAuto
What's not really point out is, the torque required by the engine to spin motor/generator 1 (when it's charging) causes the ring gear to want to turn. So while the engine isn't directly connected to the output, a lot of it's energy is trying to turn it over, and that 1:2.6 gear ratio means the torque from the engine to the ring gear is 2.6 times greater than it is to the generator. So, when you're driving down the highway with the engine running, it's power is getting to the wheels by motor/generator 1 acting like a brake, which causes more torque to the output. Except it's not a brake, it's generating electricity which is feed to motor/generator 2 to also help turn the wheels.....and while this isn't as efficient as a normal gearbox, the efficiency comes when you slow down and the kinetic energy is turned into electricity and stored in the batteries for future use.
This video answered almost all of my questions about my car's transaxle. You have explained the component in such an elegant way and you bring it to life! I feel lucky to have access to your teaching content. I'm sure your students do very well upon graduation. I have a quick question: Why does the damper system slip and for what purpose? Once again, thank you for providing your wisdom and years of teaching experience to us-- I've learned much about how my car operates and I subscribed quite a while back. Best Wishes! Keith Nettles, RN.
@supermachoman222 Hi, MG2 is not connected directly to the engine. MG2 rotates to propel the vehicle even if the engine is off. When the vehicle is stopped MG2 is also stopped. The engine can run with the vehicle stopped if the high voltage battery needs to be charged or if the engine or the catalytic converter needs to be warmed up. Regardless of what you read for fuel economy ratings, all three of my hybrids get better fuel economy on the freeway than in the city as long as you don't speed.
I think every person that loves tech but also cars and therefore could never drive a Prius should know something: You can buy this exact system with scaled up components in a rwd chassis. Lexus sells this in their hybrids, or at least used to until very recently. Sold me on a GS450h F Sport....
@sosarres Hi, thank you for the nice comments. Let me know if you need help transferring to WSU. We also have an online option for a B.S. degree in Automotive Technology.
Hi, yes there can be force passed from the ICE to help MG2 power the wheels. How much dependent upon the variable speed differential between the three components of the planetary gear set. For example, if the engine and MG2 are both rotating at 3000 rpm, the planetary gear set functions like one solid piece. At that point the torque from the engine + the torque from MG2 add together and is delivered to the wheels. If the ICE is off, the torque from MG2 is all that powers the wheels.
This works practically in identical fashion to the Owen Magnetic of ~1915. The principle difference being the use of the planetary gear set, which allows the generator to be smaller, and eliminates the need for brushes and collector rings. In both cases, however, the reaction torque generated by the generator (MG1) (as a result of the engine driving it) mechanically assists the traction motor (MG2) in providing drive power, reducing the amount of power which must take the (somewhat less efficient) electrical path. The Owen Magnetic did not use a battery to supplement engine power, and therefore is not a hybrid. Reverse will be achieved by reversing the traction motor (MG2) in all cases, engine running or not. Attempting to drive the wheels via MG1 would also apply torque to the engine, very likely causing it to turn.
So if there are 2 battery banks one can charge and other can be used to power the vehicle act as a range extender, gasoline engine can be used to recharge the batteries possibly eliminating to charge the vehicle using an external charger
Great explanation! Same principle (power splitting) as in the Fendt tractors. They have a hydrostatic branch instead of the electric one in the hybrid cars though.
We have been driving an '09 Prius since it was new. The car still fascinates me. When I watched this video I was impressed at how simple the drive train is MECHANICALLY!, and how sophisticated it must be electrical/electronically!! I mean, just to make this thing drivable would be a feat, then to make it smooth, and perform well, and optimize efficiency, my goodness. I can not even imagine all that has gone into the controls. I still wonder, what is really happening when I step on the accelerator? Then, what is really happening when I step on the brake?? Haven't even delved into that system.
I already have had a solid understanding of the PSD, but it's great to see it as implemented in the actual, physical parts themselves! I have a question regarding the connection to the engine: It has a clutch, that (I think I heard you say), is always engaged. Based upon that alone, I presume then that it's only purpose is to prevent a sudden lurch when the engine turns on or off. That is, it would slip just a little bit during those transitions, but otherwise always be fully engaged. Is that the idea? Later on in this video, however, as you were demonstrating its operation, you held the "engine" stationary. Does there exist a brake somewhere in this clutch structure?
WeberAuto Thanks. Actually, I had a second question there: In the video, around 70% through it, you hold the "engine" (clutch plate) stopped. Does that suggest that there's also a brake for the engine, in EV operation?
WeberAuto Gotcha. Thanks. I understand that, on the Prius Prime, they added a sprag clutch, preventing the engine from turning backward. This allows MG1, in addition to MG2, to be used for used for EV drive. I gather that the sprag clutch gives MG1 something to push against (well, to torque against, more precisely).
Another car enthusiast here. I already appreciated the Prius, not for being an enthusiasts car, but for being an extremely reliable and quite comfortable runabout. Now I see how it works, and how advanced yet simple it actually is, I'm starting to see this car somewhat as an enthusiasts vehicle :-)
Fairly reliable, this CVT has its issues too. Overheating, slipping, lurching or jumping. It’s vulnerable for issues as any CVT. I do like Toyota’s and their reliability but they do have issues. Just poke around on google and there are groups who have complaints about this costly CVT
@@jeffsond lol, I don't know what you're on about - technically it isn't even a CVT :) only issue I hear that comes up regularly is the cooling system failing (and resulting issues after continued driving without appropriate cooling)
This car is loved by places and countries that have remote driving area and poor service distribution, as it is much reliable than conventional cars transmission and engine is, also, very robust for those markets. Because, most of the time cars do not drive fast long enough and have to slow down or break often, and accelerate again. Up and down hill offer good petrol saving, and engines do not overheat as much.
@@4nz-nl maybe try doing more research and you will see what I’m talking about. It’s real simple
@@jeffsond That's not how you get away with not supporting your claims ;)
I heard that the fuel injection begins only after the engine has been spun to operating rpm by MG1. That explains why the Prius has very clean emission despite the frequent engine start and stop. In regular cars, the starter motor only turns the pistons to proper firing positions, the first few burnings may not be clean when the engine is not yet in ideal rpm.
Hi, thank you. You are absolutely correct regarding reverse. I realized my error after shooting the video, but nobody ever said anything until you. What I should have said is that MG1 will spin the opposite direction of MG2 in reverse because the planet carrier is stopped with the engine off. This allows MG1 to start the engine if necessary (which mine usually does upon cold startup) while backing up.
I recently bought a 2007 with super low miles on it.....the more I learn about the Prius the more I appreciate it.
Good to hear! Thanks for watching
I recently bought my first hybrid, a 2025 Honda Civic. So I started watching these WeberAuto videos and I have to say that Professor Kelley has become a person I admire greatly for the detailed and precise work he has done to not only analyze these systems but also create these presentations for all of us to benefit from. I see that he is wheelchair bound now but it has not slowed him down one bit. He is an inspiration and I humbly say thank you sir.
I just bought a prius and am a motor mechanic. I just learnt something new! What a clever transmission!
As a car the Prius has many faults which prevent it from being an automobile for enthusiasts. I used to belong in this camp, until I've recently driven a Prius C.
After driving it and doing the research behind the technology (and especially the eCVT), you have to be amazed that Toyota figured out how to use a single planetary gearset so efficiently before anybody else did and made the hybrid system blend EV & gas power so well. Well done on the explanation!
Trades46 Thank you for watching!
Trades46 My understanding is that the Power-Split Device ("PSD") was originally patented by a group of California inventors. Toyota made it work though, kinda analogous with the Wankel engine having been invented a long time earlier, but Mazda made it really work.
Can you List a few of the faults?
The motor in the Lexus hybrid is even more smooth on blending EV and gas. I love it. Never thought I would like a CVT
I have a Toyota Aqua (prius c) and I see nothing in it that prevents it from being an enthusiastic vehicle.
There’s nothing inherent with a PSD Hybrid that stops you from driving, racing, or having fun with it.
I’m curious what you used to think those “inherent faults” are other than “cars that were designed specifically to sacrifice performance for efficiency don’t have as much performance as cars that do the opposite”.
Big surprise.
Toyota’s Prius holds a well-deserved place in the history of great technical accomplishments. Ingenious, groundbreaking, bold, and most amazingly, a smash sales success. Kudos to Toyota.
Amazing presentation!!! A true engineering marvel, clearly explained. 15 minutes that made me smarter!
I've searched a lot of videos to understand how Toyota's eCVT works and your video is the best explanation I've seen so far.
A terrific tutorial on how the unique Toyota Prius transmission works and it answers a lot of questions that I had. THANKS !
A very nice and clear explanation on the Toyota Hybrid drive system, and unusually accurate as well - Very nicely done.
My only point would be that MG1 never drives the car. When going backwards it is always MG2 that provides the motive force (just like when going forwards)
Whilst driving backwards MG2 is the motor and MG1 will be freewheeling, unless the engine needs to run in which case MG1 is a generator charging the battery (Providing the electricity for MG2 to drive the car)
Best explanation of the Prius hybrid system I've seen yet, and it's a 13 year old video!
This is one of the best videos explaining how the ECVT works. It is amazing how Toyota innovated such a simple yet effective solution using only a planetary gearbox. Thanks for the excellent explanation.
whoa... hard to believe this is a 12 year old video. I'm not a mechanical engineer in any shape or form, but was able to follow along and understand your every point. Great information, and extremely well presented. Thank you for this!
Thank you very much
I am loving these Hybrid cars. I recently purchased a used 2008 Prius and I am fascinated with the technology that goes into these cars. The Prii are also immensely reliable. You tend to see many in the road sitting pretty at 200, 300 and 400k miles on them.
Yes they are, Thanks for your feedback
My pleasure 8-)
Funny how 200k is "immensely reliable" when a 90s Saab's break-in is like 300k miles :D Haven't had one for a while though, just got a 08 Prius too.
@@esaedvik Shame Saab is no longer around. They were good cars indeed
@@ErickMartinSucre They are though and NEVS just got a bit of extra cash, so there's still hope for a Saab 9-3 or 9-5 EV :)
I've always chosen to drive manual-transmission cars, because I like their mechanical simplicity compared to automatic transmissions. I'd assumed that hybrids were even more complex, so I've never been interested in them. However, after looking at this video, and the excellent companion video of the 3rd Generation eCVT, I'm impressed by the overall efficiency and simplicity of the Toyota concept. I'll definitely consider a Toyota hybrid for my next car.
Thanks for your feedback!
Late reply but these transmissions are the most robust and reliable I have ever experienced. Never had any issues with them, even well into old age 450,000kms and beyond. The most I've seen is some leaky seals so some splash lubricant can leak but the actual mechanism used in the first and second gens are phenomenal. Can't say the same for brand new junk 😂 but our first gen Toyota Highlander is an absolutely outstanding vehicle
There is an incredibly detailed and well done software available to the public called Hybrid Assistant that allows you, in real time to monitor every possible facet of MG1, MG2, and everything from high voltage battery real time charge and decharge, temps, all combustion gauge values even high voltage fan speed. Having these values real time is crucial if not just for the fact that only a Toyota hybrid is monitoring that many systems, and just as a space shuttle launch command - after a while you start to understand the personality of your vehicle so you can understand what is going on with her before a possible incident or how to achieve performance or efficiency.
I love driving my hybrid systems with all that real time data
You need a good OBDII sending unit and you’re good.
I was a Diesel mechanic a lot years ago. The pace that technology and engineering growth since the 70's has been staggering.
Great video. I wish the audio was a bit clearer and there was some close-up shots. But still one of the best explanation videos out there. I've seen diagrams of how this stuff works, but seeing the actual parts really makes a big difference. I actually always imagined many of those parts being quite a bit larger than they really are, especially the planetary gear set. MG1 and MG2 look small, but I think because we're not seeing them with the stators around them.
The 8-Bit Guy cool you’re here! You should do a video on your Volt and talk about stuff like this. Like the electrics behind it.
Funny to see you here..,10years ago lol
Wow
@sosarres 2. (Vehicle moving) Rotate MG2 (ring gear), MG1 rotating more than 2.6 times faster than MG2 (sun gear), the crankshaft (planet carrier) will rotate to start the engine. There is also a time when the crankshaft will be rotated but the engine is not intended to start: Full battery charge, decelerating down a long steep hill, regenerative power has to go somewhere so it is used to rotate the crankshaft with MG1 to dissipate the additional energy.
I understood the mechanism after years of trying to understand reading and watching animations. thank you.
So this is how the sequential parallel system works. I love the simplicity of it as the ring, sun, and planetary gears are the only mechanically moving parts in the transmission, and by simplicity adjusting power/drag to MG1 you effectively control the entire ratio range. It's also ultra efficient as when MG1 is driving the sun gear for a high wheel speed, that energy ends up at the wheels too outside of friction losses, and when MG1, MG2, and the combustion engine are RPM matched, the entire transmission moves as one part, and as such there's no friction from the meshed gears
Lecturer is brilliant. Explains a complex scenario in a very logical and enjoyable manner.
I am of the age where Japanese designs in the early days were mostly poor copies of European ideas, which is contradictory to todays Toyota engineers have shown by this drive system to be creative and innovative.
Alistair George Except this design was originally by 4 engineers in California in the '60s.
eCVT is so much better a design than a regular cvt. I hope all cvt go to the eCVT design.
This is the best explanation ever, I now finally understood what my RAV4 hybrid does when driving!
I thoroughly enjoyed this video, my hat off to you sir, you're a remarkable teacher with a natural ability to impart information.
As with most engineering systems, the fundamentals are straight forward when you understand how they work as a system. Explaining these fundamentals in an easy to understand way is often not so straight forward, again, great job sir.
#Respect.
Thank you for this presentation. This vehicle is not completely a independent novel concept since it incorporates a lot of technology that may be familiar to other transportation modes such as freight trains. Having said that, it is undoubtedly the pinnacle of Toyota's engineering with conventional and electrical propulsion . I also get lost in the details of wheel and tire technology used, also weight distribution and energy use and conservation. Your poise as a teacher is also reassuring
This video gives the best explanation for how the Toyota eCVT works. I now think I understand the concept. Well done sir and hats off to Toyota for creating this beautiful y engineered system!
Great explanation! I can’t believe how small it all is and that there is no cvt belt. It’s nice to understand my car more.
Wow! In just a 15 mins you've explained a two things that I've tried to figure out for years. Thank you very much!
Thank you!
this channel is really a gem. Always have good explanation and professional knowledge. Thanks!
@luvmygooose 1. The P112 transaxle input damper (looks like a clutch disk) absorbs the shock that accompanies transmission of the drive force from the engine. It is permanently applied. If it slips, a P0A90 DTC will trigger for a transaxle input malfunction.
2. The vehicle can move on Motor-Generator 2 (MG2) power alone (up to near 37 MPH) or a combination of both the MG2 (driving the ring gear) and the Internal Combustion Engine (ICE) driving the planet carrier (at all vehicle speeds).
Best explanation of Toyota's e-cvt I've seen to date. Thanks!
The best explanation of ecvt I could find! Thank you so much!
Thanks for watching
Yes, they are! They are used in conjunction with a drawn reciprocation dingle arm on the up end of the grammies for sinusoidal repleneration. :)
A+ video. Don't see why there would be a single dislike.
Thank you!
Finally i understood. Thanks! Thats a pretty great invention.
I'm on my 3rd Prius, 7 years ago I wouldn't even look at a Prius, but it's a great car for reliability I put 320k on my 2nd one with no problems at all NOTHING BROKE DOWN. I've always wondered how the assembly worked. So a big thank you for the video don't worry if you are considering buying a Prius don't worry great car for reliability
this video is great! thank you. i love the way you repeat the roles of different parts in different contexts -- makes it much easier to learn!
Transaxle damper has internal springs to sort out the vibration when the engine starts and stops, to reduce the shockwave through the drive train. The Friction material the there in case of a catastrophic failure or the engine at speed to make sure that the roads wheels don’t lock or destroy MG1 by over revving.
Came back after many years, & finally understand it.
Wow! This video is old but gold.
Btw, you missed the part in which the motor needs to operate in order to discharge the battery to prevent it from being overcharged.
just want to say i watch a lot of videos, but your videos are the best i ever saw. i am a mechanic myself and love to check your videos. thanks a lot , would like to your workshop one day,i am in south africa, thanks again.
pjw coetzee Thank You!
Your video is a work of art!
Thank you!
A beautiful beautiful work of art! great invention, Thank you very much Sir!
This explains the hybrid transaxle operation very well. Thank you.
It is really smart and very small. I was expecting the MG1 and MG2 be much bigger, and closer in size. The size of the planetary gear set is also small. Amazing.
Best dive into the Prius gen 2 I've seen. Running 2( 2008 w/ 220,000 and 2007 w/ 290,000 ) gen. 2's currently. Love them but '07 needs at least one new batt. cell( death triangle getting consistent). Even a Prius needs some maintenance!
@sosarres Hi, you are correct when you state that the engine's crankshaft will rotate at the same speed as MG1 (when MG1 and MG2 are rotating at the same speed as each other); however, this is not how the engine normally is started. The most common ways the engine can be started are: 1. (Vehicle stopped) MG2 stopped (ring gear), rotate MG1 (sun gear), the crankshaft (planet carrier) will rotate to start the engine.
My favorite part about the Toyota hybrid platform is actually the transmission... what drew me to Toyota was their hybrid platform. My whole family owns a hybrid from Toyota now because of how reliable and efficient they are (five vehicles now... I'm on my second hybrid, nothing wrong with the first one, just wanted a new car... 2020 Corolla hybrid). Love the buttery smooth shifts even at 100k miles. I hate autos with fixed gears, shifts thumping, sticking, hesitating, so on and so forth... especially with age.
感恩了解，謝謝分享！
Outstanding lesson!!! I have a 2022 Tundra hybrid on order with a 1.87 kWh battery and now I know the basics and understand MG1, MG2, planetary gears, sun gears, etc. I find it fascinating that an “old school” starter and alternator are not required with a Toyota hybrid system.
Very informative. To think I only recently understood how my Spitfire's overdrive works(when I was rebuilding it)
@supermachoman222 Hi, I appreciate your comments, but they are incorrect. During electric only mode MG2 propels the vehicle and the engine's crankshaft is stationary; there is no piston movement. This mode is only used up through a maximum of 40 mph. Afterwards, MG1 acts like a starter motor and does start the engine to contribute power to MG2 and to slow down MG1. This is very efficient resulting in the best city fuel economy of any hybrid-electric on the road.
This is FASCINATING!!! Thank you!
@WeberAuto you sure can't! Terrific video, you really did well with this. Excellent preperation well done
I'm confused. Did I miss the part where he talks about the variation of the transmission? I want to know how the car do basically do whatever speed at 2k engine rpm.
The speed of the output (MG2) is controlled by the ratio between the engine and MG1. To speed up MG2 while keeping the engine constant MG1 has to slow down, and vis versa.
Awesome video! I had know idea my lexus hybrid system so complex...and I now understand it. I always thought it was just a electric motor that replaced the flywheel or something like that. Thanks!
+stevenfirst Thanks for watching!
brilliant explanation! Thanks so much for taking the time to produce this.
Thank you for a thorough explanation
Wow! This is really clever desing, and rather simple.
Amazing explanation of the eCVT operation! Great Work Mr. Kelley, please keep making more videos like this one.
Also, this video ends abruptly. Could you kindly explain what happens next? that is what happens at a much higher vehicle speed? how does both ICE and MG act in parallel mode via the eCVT?
Thanks
Awesome description. Thank you.
Thank you
Now I want a Prius!
Thanks for your feedback!
I have a Prius 2 for 12 years now. Just great to drive and so economical. When you reach your destination in Prius, you would like more road ahead.
Thanks WeberAuto
J'ai une Prius 2 depuis 12 ans à présent. Juste génial à conduire et tellement économique. Lorsque vous atteignez votre destination en Prius, vous voudriez que le route continue.
Merci WeberAuto
143 000 km for the moment. Only the water pump + belt of the engine changed. Tires changed and usual car service done each 15 000 km..@Luca Rossi
@Mrcamfam5 Thank you for your comments, it is a very simple mechanical design.
What's not really point out is, the torque required by the engine to spin motor/generator 1 (when it's charging) causes the ring gear to want to turn. So while the engine isn't directly connected to the output, a lot of it's energy is trying to turn it over, and that 1:2.6 gear ratio means the torque from the engine to the ring gear is 2.6 times greater than it is to the generator.
So, when you're driving down the highway with the engine running, it's power is getting to the wheels by motor/generator 1 acting like a brake, which causes more torque to the output. Except it's not a brake, it's generating electricity which is feed to motor/generator 2 to also help turn the wheels.....and while this isn't as efficient as a normal gearbox, the efficiency comes when you slow down and the kinetic energy is turned into electricity and stored in the batteries for future use.
This video answered almost all of my questions about my car's transaxle. You have explained the component in such an elegant way and you bring it to life! I feel lucky to have access to your teaching content. I'm sure your students do very well upon graduation. I have a quick question: Why does the damper system slip and for what purpose?
Once again, thank you for providing your wisdom and years of teaching experience to us-- I've learned much about how my car operates and I subscribed quite a while back. Best Wishes!
Keith Nettles, RN.
Thank you for the explanation.. Was really helpful in getting a practical understanding of the system!
@supermachoman222 Hi, MG2 is not connected directly to the engine. MG2 rotates to propel the vehicle even if the engine is off. When the vehicle is stopped MG2 is also stopped. The engine can run with the vehicle stopped if the high voltage battery needs to be charged or if the engine or the catalytic converter needs to be warmed up. Regardless of what you read for fuel economy ratings, all three of my hybrids get better fuel economy on the freeway than in the city as long as you don't speed.
Excellent explanation. Thank you for making this video 🙏
I think every person that loves tech but also cars and therefore could never drive a Prius should know something: You can buy this exact system with scaled up components in a rwd chassis. Lexus sells this in their hybrids, or at least used to until very recently. Sold me on a GS450h F Sport....
Excellent demonstration, I learned a lot - thank you.
Thank you!
@sosarres Hi, thank you for the nice comments. Let me know if you need help transferring to WSU. We also have an online option for a B.S. degree in Automotive Technology.
Hi, yes there can be force passed from the ICE to help MG2 power the wheels. How much dependent upon the variable speed differential between the three components of the planetary gear set. For example, if the engine and MG2 are both rotating at 3000 rpm, the planetary gear set functions like one solid piece. At that point the torque from the engine + the torque from MG2 add together and is delivered to the wheels. If the ICE is off, the torque from MG2 is all that powers the wheels.
Just about to buy a Yaris or Prius so thank you for the explanation on how the drive train works very impressive a good job well done
Very good explanation. Thanks. But wow, what an abrupt ending.
This works practically in identical fashion to the Owen Magnetic of ~1915. The principle difference being the use of the planetary gear set, which allows the generator to be smaller, and eliminates the need for brushes and collector rings. In both cases, however, the reaction torque generated by the generator (MG1) (as a result of the engine driving it) mechanically assists the traction motor (MG2) in providing drive power, reducing the amount of power which must take the (somewhat less efficient) electrical path. The Owen Magnetic did not use a battery to supplement engine power, and therefore is not a hybrid. Reverse will be achieved by reversing the traction motor (MG2) in all cases, engine running or not. Attempting to drive the wheels via MG1 would also apply torque to the engine, very likely causing it to turn.
Thanks for your feedback
So if there are 2 battery banks one can charge and other can be used to power the vehicle act as a range extender, gasoline engine can be used to recharge the batteries possibly eliminating to charge the vehicle using an external charger
Brilliant video
Thank you
Very good demonstration
Thank you!
Very clear and helpful. Thanks!
Thank you!
Amazing video. I'm taking the hybrid specialist exam soon and was looking for a Prius visual aid since I'm with another brand. Great work sir!
Thank you, Best wishes on your exam. Study Toyota hybrids, the exam is heavy with Toyota questions.
I passed the ASE L3 exam today, thanks for the help!
That is awesome, congratulations!
Thank you. I'm going to ask my parts department if we can attain some take-off prius parts to train our guys with. Keep up the good work!
Great explanation, God job!!
Thank you!
So Toyota’s eCVT is completely different from Nissan’s belt based CVTs? Neat!
Yes, no belt in Toyota
@@WeberAuto so theoretically it should take more abuse.
This is a really good video Explaining how it works. I have always wanted to know.
Thank you
Well explained and brilliant design.
Thank you!
Thanks Professor Kelly. Regards, Ramish.
Thank you very much!
Wow that was a GREAT demonstration. Thank you
I agree this was a great demonstration.
Great explanation! Same principle (power splitting) as in the Fendt tractors. They have a hydrostatic branch instead of the electric one in the hybrid cars though.
Great explanation, many thanks!
Thank you!
Outstanding video
Thank you!
We have been driving an '09 Prius since it was new. The car still fascinates me. When I watched this video I was impressed at how simple the drive train is MECHANICALLY!, and how sophisticated it must be electrical/electronically!! I mean, just to make this thing drivable would be a feat, then to make it smooth, and perform well, and optimize efficiency, my goodness. I can not even imagine all that has gone into the controls. I still wonder, what is really happening when I step on the accelerator? Then, what is really happening when I step on the brake?? Haven't even delved into that system.
I already have had a solid understanding of the PSD, but it's great to see it as implemented in the actual, physical parts themselves!
I have a question regarding the connection to the engine: It has a clutch, that (I think I heard you say), is always engaged. Based upon that alone, I presume then that it's only purpose is to prevent a sudden lurch when the engine turns on or off. That is, it would slip just a little bit during those transitions, but otherwise always be fully engaged. Is that the idea?
Later on in this video, however, as you were demonstrating its operation, you held the "engine" stationary. Does there exist a brake somewhere in this clutch structure?
Yes, that is correct.
WeberAuto Thanks. Actually, I had a second question there: In the video, around 70% through it, you hold the "engine" (clutch plate) stopped. Does that suggest that there's also a brake for the engine, in EV operation?
No, it just off. The resistance of compression stroke on two cylinders will prevent most crankshaft rotational motion.
WeberAuto Gotcha. Thanks. I understand that, on the Prius Prime, they added a sprag clutch, preventing the engine from turning backward. This allows MG1, in addition to MG2, to be used for used for EV drive. I gather that the sprag clutch gives MG1 something to push against (well, to torque against, more precisely).
Thanks for a very useful video
Hi, Reverse can work with the ICE on or off. The difference is the rotational speed of MG1
Thank you, for explaining. From Russia
Perfect explain!!
Glad you liked it
Thank you for explanation!
MG2 connects to the final drive with a 1:1 ratio, but the final drive ratio is near 4:1
WeberAuto what is a Atkinson motor