This guy disassembled this whole trans axle, labeled everything, made sure he know how everything worked, buttoned it all back up and only then started filming. A lot of extra effort to make the video better, easier to follow and accurate. Awesome
Dear Professor, as a mechanical automotive engineer and the owner of a Gen III 2010 Prius (with 305k trouble-free miles) and a new 2018 Gen IV Prius, I am in awe of the quality of your work. The quality of your videos and the clarity with which you explain all the aspects of the Toyota hybrid powertrain are unparalleled. Thank you very much and congratulations to you and your team!
You really are a teachers teacher. At 1:52:43 you describe the continuously variable part of the transmission as the interplay between the engine and MG!, and you do it almost as a casual aside. That is such a genius idea and yet you say it as if it were just an afterthought. You are the most gifted explainer I have ever come across. You have my highest regards.
I could have lived the rest of my life not knowing differential components of my car are pressed together. Now I’m gonna think about that every time I step on the gas. Love these videos.
Hi Professor Kelly, I just wanted to take the time to say thank you so much for these incredibly detailed and informative videos that you post. Automotive mechanics has always been something of a passion of mine (I have a 1996 Honda Accord EX-V6 that I baby and am always looking for something to get to fix on it) but pursued a degree in I.T. which is what I am doing now, as much as I want to pursue a career in your field. If I am not watching a video of yours as intently as possible I also find the way the videos are designed to be a bit therapeutic and make sleeping a breeze! Lol! Thank you so much for these videos again!!!!!
Excellent video, really appreciate the depth that you went in to. At about 55 minutes in, a comment was made that MG1 has 5 lobes on the resolver, while MG2 has only 2. It looks like MG1 has 10 magnetic poles, so five North/South pole pairs. MG2 looks like it has 8 magnetic poles, or 4 pole pairs. So for every lobe on MG1, they know where the North poles of the rotor are. If they had only two lobes on MG1, they would only know that a North or South pole was at that location, because one lobe might point at a north pole, while the opposite pole might point at a south pole. For MG2, they know that a north pole is located by either the lobe, or the valley between the lobes.
I was able to find the magnet configuration in a paper from Toyota engineers that describe the P610 improvements. The configuration is much like a bent staple, and what seem like tiny magnets are indeed just the two side magnets at an angle terminating around that point. The three magnet configuration was designed to be "closer to the fundamental harmonic thus making the motor more quiet". The paper is titled "Development of New Motor for Compact-Class Hybrid Vehicles". Thank you so much for this video! I just love learning anything I can about this marvel. Your videos are a priceless contribution to the world of engineering.
You are fantastic! I was a military instructor for mechanics for 6 years during my tour in the army and I have to say you are a great teacher. I love all your videos. You are Bob Ross for mechanics!
Professor Kelly, i own and drive daily a 22 Prius Prime. I have owned both a gen2 and gen3 Prius prior to my current car. I have tried through the years to purchase cars later in their cycle (buying a 22 instead of a 17) because the engineers and QC at Toyota have had time to deal with any issues and provide the most reliable product within that generation. Ive purchased the technical manuals for each car and applaud both your accuracy with specifications as well as your ability to teach about something so complex. You present without frills or drama and make it so easy to understand. You have contributed to my better understanding of these products and their serviceability. More importantly, all your videos inspire me to learn more. For this i am truly grateful, thank you. As a mechanic i wanted also to reitterate for viewers that your unique and detailed knowledge of the products you dive into could not be obtained without taking them completely apart and putting them back together again. Its risky work and want to thank you also for the huge investments that you make of your time to do this. I feel you truly have fulfilled your purpose here on earth and hope you may continue to do so, helping so many of us to better understand these cars.
You’re a good man and instructor, thanks. Something about this p610 is different from an older model, there is no internal drive chain, didn’t see one in this video, that’s a good thing, eliminated is the word I like to use, simpler is good engineering
I'm a qualified tech with Toyota training specific to the HSD. I also reconditioned battery packs professionally for several years with success. I can honestly say I've learned more from this channel than any other source...excellent work and mountains of knowledge...appreciated.
Professor Kelly, you are amazing. If I had only known of you and your school years ago... Thank you for your generosity and commitment in making all these videos. If I was younger I would be applying for next semester.
Professor Kelly. I’m 72 years of age I’m in Australia and u would call me here a bush mechanic (a self taught from the age of 19 years old. )Your explanations of that engine and electric gearbox was awesome. I would like too know how to see more of your videos. I also noticed how nice and clean your workshop is .
@@iskaarak6503 watch more videos, get a car to wrench on. Getting familiar with any car and it's operations will help with your knowledge of any machine. Went from no car knowledge to comfortably changing my clutch on my own with only 2 tiny jacks. After that I fixed the electric seatbelt motor without any issues or any looking up for blow ups or forum help..
You are one of those few guys one stumbles upon, who knows their sh*t ,as we used to say. Interesting to see someone use a somewhat monotone delivery, no crazy graffics, or pontificating.. just brilliant dry analysis of fascinating tear downs. Keep it up you're teaching more than 99percent of academia.
Dear Professor I'am a MV Lecturer at croydon College ,London my name is Derek that was the most informative detailed strip down, excellent explanation of component operation, we will using your website to comp[ete our CPD at work. Love your workshop.
Excellent work sir. So nice to see machines when they are new. Having spent countless hours struggling with frozen fasteners and greasy grimy components it’s a real pleasure to see them in such a clean environment. Makes a great case for taking the time to keep vehicles clean and degreased.
Wooo, best teacher i finally understood how my p610 works. 100% understood. What how and why my prius prime does something. Thank you for all. Time, work, research, math... i did not miss any second !
Seeing someone in a wheelchair disassemble & explain the transaxle of the Prius was super inspirational. Cool technology! Nice video! Nice and detailed!
Wheelchair or wheelchair not, excellent job. All his videos so far are excellent. I can’t believe the lengths he went through to make this vid. But I like his curiosity.
I stumbled across this RUclips channel while searching for something to help me study for ASE auto trans recert. You can't pay for classes this good. Our manufacturer classes that last several days aren't as in depth as what this guy does in an hour or 2.
Nice video, I'm impressed by this tansaxle. It look and feel like there is not cost cutting in this. The MG2 stator is very impressive, it seem to be built like an high end industrial motor. I guess the prius 4 will continue the legacy of being one of the most reliable car on the planet.
Thank you very much for your hard work and vast amounts of time making these videos. I have been an automotive tech for 30yrs. now. You do a fantastic job describing/visualizing theory and operation. Im certain people with little vehicle knowledge can, at the very least, understand the principles put forth here. I work mostly on Toyota products and have many Prius repairs to my credit. I have consistently seen gen 2 Prius with 300k and up. Personally, I am whiteness to a gen 2 that made it to just over 800k of service with a transaxle that was never serviced (except for fluid changes). No leaks, no quirks, it functioned perfectly. That is simply amazing. As an owner of a gen 2 and 3 Prius I give Toyota and its engineers an lot of credit for their work 30 plus years ago when they started working on this radically different design. They went out on a limb back then. Toyota had to make them do more then just work for a little while(planned obsolescence). Those units had to be reliable and go the distance in order to sell their new technology to the masses. I think your videos show how they achieved this. I am lucky I can point customers to your videos when they ask me how their Prius transaxles work. Thanks for educating.
Wow! I'm a NATEF master instructor and have my own channel, and you have blown me out of the water! Thanks so much for this, and I will be subscribing and following you.
John, I waited for this video to upload before releasing our Prime review and have included links to this video along with links in video to your content about the P610.
The configuration of the magnets are in a halbach array arrangements it's purpose is to make the emf polarities of the back of the magnets concentrate towards the front as to provide a substantial amount of force facing the stator it is a technique also used in particle accelerators
I LOVE this channel! I think you will have a difficult time finding any videos that cover this type as content as clearly, competently & completely as they do here. I want to thank the channel owner & the gentleman in the videos for providing such high quality videos! It is so nice to be able to see how things work & get a great explanation of how & why they do what they do. Thank you for what you do!!!
I like the organization of the Prof. The explanation is really a show. For us here in Brazil these kind of videos are priceless. full of details. Lucky the guys, that have the chance to participate of these "classes" with the Prof.
Thank you very much for an interesting video that really explains how it all works. Fascinating understanding of how the combustion engine and the electric motor cooperate.
Thank you very much for the video. Well organised, professional introductions and advice and slow and clear speech that I can not miss any detailed explained. Great work, keep up good work. Thank you.
I love that it has so much tech, yet still uses that old fashioned looking open diff, I figured these would at least have worm gears. I’m glad I found your channel, man I might need to come to your school….looking at getting out of truck driving and going back into these newer electric drive vehicles. Gotta stay with the times.
Wow, just found these! Thanks for taking the time to produce these wonderful videos. I especially appreciate your details, decals and depth that you have gone to document the interior components. This is really helpful for the daydreamers (myself included) in integrating these now more readily available hybrid components in motorsport applications. Really looking forward to checking out the DC BUS and VFD components in the drive control box next, Cheers!
I really like your videos. Very professional indeed! Looks like this is the best education about cars, that you can buy with big money, but no! This is free, and maybe even better, than some of these technical schools with tuitions. I`m just very impressed about this amount of knowledge. good work, keep going!
Dear Professor, thanks for your great video! The reason for the number of resolver poles is that a resolver can not provide the absolute rotor position. Within one mechanical revolution its position signal repeats itself by the number of pole pairs, so you have an uncertainty of 360 deg divided by the number of resolver pole pairs. For the field oriented contol of the inverter it needs to know the relative position of ANY pole pair of the machine. To ensure this, the pole pair number of the resolver must match or be an integer division of the pole pair number of the machine. The MG1 has 5 pole pairs so the resolver must have the same. The MG2 has 4 pole pairs, so resolver pole pairs could be 1,2 or 4. Due to mechanical imbalance, 1 is no option.
Forgive my oversimplified thought: Would it be correct to say that the Resolver provides position reference to allow Motor Movement between poles AND the Resolver position reference minimizes an uncommanded motor movement which would otherwise be in either direction of rotation. # Uncommanded motor movement?
@@anthonyrstrawbridge I'm not sure if I got your question right. The inverter needs to know the relative position between the rotor poles and the stator winding. Based on this position information, the inverter can inject the right current amplitude and phase to generate a given torque as well as rotation direction. Please, feel free to ask if this doesn't answer your question.
And yet in 1987, Toyota had a very accurate and reliable engine oil level sensor for the engine in the van that I had. That was 34 years ago. Why isn't a similar sensor installed here. It creates great peace of mind to know for sure what your level is.
I just took delivery of a 2023 Rav4 Prime SE, and drove it 3,200 miles from a Toyota dealer in Baltimore, MD back home to California. The P-810 transaxle is awesome! The Rav4 Prime is a heavy car, something like 4,300 pounds curb weight, yet the powertrain (18kW battery, ICE, MG2, and MGR) lets the car climb 6% freeway grades with no feeling of stress of strain at all. On the downgrades, the regen braking holds the vehicle at whatever speed you set the cruise control at, perfectly. No need to touch the brake pedal at all. It was a joy to drive, the only (slight) flaw being that I'm a bit on the tall and heavy side, and I might have wished for a slightly larger driver's seat that supported my legs more comfortably. The transitions between EV and HV modes are so smooth and quiet, that they are all but un-noticeable, same as in my 2019 Prius Prime, and the 2.5 liter engine is so well insulated in it's mounting, that it's hard to hear even at 3,500 rpm. At normal cruising, 1250 to 1800 rpm, it's virtually silent. Great job Toyota, and thank you Professor Kelly for all these deep dive videos on the HSD transaxle, to help me visualize what's happening under the hood, so that I can be a better driver and get the most performance out of my Toyota HSD, while at the same time protecting my investment.
Thank you for an excellent series of video presentations! On the planetary gear set I want to add: The sun gear is not part of MG1 shaft in all versions but rather splined to it. The planets carrier shaft is connected to the engine crank shaft via the dampening clutch. Both these elements have some radial flexibility which will not be there without, this slight radial 'freedom' is essential IMO for the operation of the set, components can be self-aligned by load exerted so the load is equally distributed into 4 (4 planets, 4 sun teeth, 4 ring teeth) or 3 in case of 3 planets set. This accurate self alignment cannot be achieved with rigid construction certainly not in the long term. This is IMO also the reason (or one of the reasons) of adding a spline adopter in the P610 - to give extra radial flexibility. One of the beauties of a planetary set is being small and compact for the load it is rated to.
Excellent presentation with a lot of details not found in the TIS publications. Thank you! The maintenance manual diagram of the one-way clutch suggests a subset of the spring-loaded teeth are engaged. Speculation on my part but engaging the one-way clutch probably needs to be done gently to avoid over stressing the teeth. The MG1, five lobe resolver cam may make that easier without having to increase the resolver exciter frequency.
Thank you! I described the engagement of the one-way clutch partially incorrect. The ICE is rotating clockwise while running, as it slows to a stop (under 400 rpm, the teeth are released from their centripetally held positions and start ratcheting. When the engine stops, the teeth are fully released and will hold the crankshaft from rotating backwards. Regarding the 5 lobe resolver cams: After shooting the video I discovered that the 5 lobe resolver cam is used to keep track of the position of the 10 magnetic poles of the MG1 rotor. the previous rotors only had 8 poles. Thanks for your feedback.
Hello and thank you for your time to teach/show us your knowledge. We'll explain video module. God bless you and I'll be looking forward to more videos. Happy holidays to you and your family
Thats why I love prius and toyota hybrids, it might be not a prettiest car, or most efficient or fastest but its a damn clever design, they simplified lots of things with this transaxle while car still have different modes of operation, variable transmission but nothing really "shifts" there, love it! Cant wait to see what 2019 rav4 hybrid will bring, it should be same design but scaled up in power, tested 2017 rav4 hybrid and loved it but it still had same issue as my 2010 prius as you couldn`t drive it faster then 40mph on electric only power, but new prius defiantly can (I actually managed to be more efficient with rav4 then with my prius as you can use electric engine in broader range and accelerate using mg2 alone and mg1 charges battery way faster then my prius does so ICE engine is barely engaged in overall trip Great channel , thanks for all the information!
I have a small question thought , from your videos I learned that 3rd gen prius high voltage battery can be charged when the car is stationary , but I usually turn car off or dont stay for long and car only charges to 3-4 bars and then shuts ICE off. Question is in what conditions prius can charge the battery the fastest while the car IS moving? My conclusion is - during hard acceleration in PWR part of ...hybrid-meter... is it correct? Its just car goes quite poorly when you have 2-3 bars of battery charge left (it doesnt really allow you to use EV mode when battery is depleted) and I want to keep it at high charge when I get to slow speed areas so I can use EV mode more freely Many thanks!
The battery control system does not want the battery charged any higher than 50% during normal operation. This is to preserve battery life. When the vehicle is stopped, it will cycle between 40% and 50% with the ICE. Any higher charge will typically come from decelerating and regenerative braking. See ruclips.net/video/2kM1-UL3yN4/видео.html I have not added sound yet, but you can see it cycle with scan tool data.
That is really interesting video , thank you, so it seems that battery indicator doesn't really represent full battery charge range but rather from 20-25% and up till 80% I assume, I have exact same prius, would be interesting to see what it does while moving as I saw some interesting modes, (1) like when its cold, car can move on electricity but will turn on ICE to heat up whole system, (if its really cold it can disable regenerative braking for a minute or two) while it seems ICE wont rotate wheels themselves or so it seems, if you try to accelerate at about 2/3 ECO bar range during this time it seems like engine wont rev much ,acceleration will be very silent and smooth! (I know its bad but only do so in emergency acceleration, still very interesting, usually car revs up fairly easy),(2) if you get into ICE range mode but then slightly depress gas pedal and go into electric range you can get fairly good MPG at low speed with ICE on (car can still accelerate at times tho),(3) in PWR range if you press gas pedal fully you can experience acceleration boost (like from 90% pressed pedal to 100% , there is a kick in acceleration) I wonder what this is, battery does not deplete as in 4th generation during such acceleration, it seems like either ICE operates in "throw in all petrol you have, there is no time for been economical!" or mg1 helps alot or whole system voltage rises up to a different level (5) also in EV mode you can press gas pedal till 1.5 electric range until it drops EV mode (or until you reach 22miles/h ) and it accelerates noticeably faster! sad thing only that 22mile/h is a fairly low speed limit when you know it can go till 35mile/h on electricity alone, even tho it will take some time....Cheers :)
What a beatiful video Thanks. But a small correction for PSD torque distribution at all ICE,MG1 and MG2 at same RPM 3240. The torque always will be distrubuted to MG1 at a ratio of %27.8 ( can be calculated from gear ratios). If they all same RPM then power will be distrubuted to MG1 at the same ratio %27.8. On the other hand, if MG1 RPM is 0, then all power will be transfered from ICE to MG2(to final drive) even if torque ratios are constant at %27.8 for MG1. Don't forget, at 0 RPM, torque is still there, but power transmission is zero...
I agree about constant 'steady state' torque distribution in the planetary gear set (and the need to consider rpm to calculate power distribution under different circumstances). In direct drive, neither all the torque nor all the power from ICE flows to the wheels, as pointed out by sedanet. It is a great video of lasting value, and I wonder if it can be edited to remove this important misconception.
Thank you sir for doing this video. I'm now studying in germany, for somehow, I think I decided to start learning about the Auto during watch this video.
I really enjoy your thorough explanation of the hybrid power trains, we have A 2019 Toyota Highlander hybrid which I would imagine Is a larger scale version of the Prius, great video thank you Professor
Awesome video. One thing to keep in mind when the vehicle is cruising down the road at higher speeds is in order to power MG1, which effectively varies the functional gear ratio between the engine and wheels, that MG2 will be generating the electrical power ("stealing" mechanical power) required to power MG1. At lower cruising speeds where MG1's rotation direction is the opposite (but torque direction hasn't changed), now MG1 operates as a generator and the excess power (at constant low speed cruise) is now fed into MG2 to help propel the vehicle. I'm not sure what actually happens at the optimal cruise speed where you want MG1 to not spin (as you mentioned), but with it not spinning it can't generate any power so my guess is MG2 continues to generate a small amount of electricity which is used to "stall" MG1 against the engine torque. Interestingly, if you think about these power split cruising modes you'll realize that power is always being wasted by the inefficiency of generating power in one motor and feeding it to the second motor in order to create the optimal gear ratio for the engine. With the ideal gear ratio a regular automatic transmission with locked TC (or manual transmission) will always be more efficient for cruising at a constant speed on the highway than these power split transaxles are. I've often wondered why there isn't a mechanical brake on MG1 and gearing selected to allow the engine to operate at an optimal rpm for highway cruising to enable optimal efficiency at 55-70 mph with zero electrical power being transferred between electric motors.
Thank you! MG1 does not help propel the vehicle except on the Prius Prime (plug-In) in EV mode. It requires a one way clutch at the flywheel to prevent the ICE crankshaft from spinning backwards. MG1 is used to charge the HV battery and vary the engine torque contribution to MG2. A mechanical brake is not needed to stop MG1, it stops on its own when changing directions of rotation. That is typically around 2340 ICE rpm at 65 mph.
@@WeberAuto I assume with your first sentence you are talking specifically about EV only mode. In hybrid mode MG1 helps to propel the vehicle at higher speeds with all of these Toyota/Ford hybrid systems (whenever the ratio of vehicle speed to engine rpm is greater than 65mph/2340rpm for the system you were working with). With our C-Max Energi this is known as "Negative Split Mode" and in the Ford manuals they also talk about it as "Highway Cruising Mode". At lower speeds MG1 and MG2 switch roles while operating in "Positive Split Mode". Yes no brake is needed to stop MG1 - but I probably wasn't clear in what I was trying to say. The issue (inefficiency on the highway in hybrid mode) is that electrical power (positive or negative depending on relative speed/rpm) is still required to generate the torque at MG1 needed to balance the engine's torque. This is true even when MG1 is stopped (eg. ICE @ 2340, speed 65 mph) and this electrical power is generated for MG1 using MG2 (when not discharging the battery). If no power was sent to MG1 the engine would essentially freewheel and not be able to do anything other than rev up. Requiring MG2 to generate electrical power so it can be sent to a non spinning MG1 is the current solution for that particular scenario but if instead MG1 had a brake designed into it then while cruising the brake could simply be engaged and MG2 could simultaneously stop generating electrical power (stealing mechanical power from the system) and this would result in improved highway efficiency and fuel economy on the highway. The overall gear ratio could be further optimized if 2340 rpm isn't ideal for 65 mph (although that sounds about right for a small sub-2 liter engine). Interestingly if you look at what Chevrolet did with their Voltec 2 Hybrid system they have a mode that enables exactly what I am suggesting (I believe the Voltec 1 did too but haven't confirmed for certain). The current Volt can, while cruising at certain speeds, connect the engine directly (through an appropriate overall fixed gear ratio) to the wheels and both MGA and MGB can completely shut down. The volt also retains the ability to use a "Negative Split Mode" and "Positive Split Mode" to take power from MGA and send it to MGB and vice versa to optimize engine rpm vs vehicle speed, but at typical cruising speeds it can further improve efficiency and run 100% on the ICE with a fixed drive ratio by engaging the two clutches. While driving in this mode MGB can still be used to supplement mechanical power if needed (drawing on the battery) or can be used to top up the battery as a generator. The Voltec 2 also has a mode where the engine sits stationary against a sprag clutch to ensure no reverse rotation that it can use both MGA and MGB to power the vehicle (similar to the new plug-in Prius). Compared to the Voltec 2 Hybrid system, our C-Max Energi's system looks quite primitive. On the highway our fuel efficiency is quite poor (7 to 8 l/100km) and having a direct drive mode would be a nice addition (although aerodynamics are likely a big part of the highway economy). Our city fuel economy is very good though and due to rush hour being so bad here we typically average 2.5 l/100km overall during a 100 km daily commute (including a daily battery charge which gives us about 25 km of EV range these days after 150,000 km; when new we got 40+ km of range; best was 55 km). Do you happen to know with our 2013 Energi at what ratio of vehicle speed to engine rpm MG1 stops turning? I've always intended to dig through the specifications, work it out, and experiment with driving the vehicle at those speeds/rpms to see how the system handles it and how the fuel economy is influenced by positive split vs negative split vs the stalled MG1 negative split state. I've also wondered if it will allow MG1 to remain stalled for long. The computer may deliberately transition through forward/reverse MG1 direction without it remaining stalled for long (MG1's coils being used at stall may eventually get hot so it may not allow it). Thanks again for the video and information.
@@Slider68 Thanks for the information. Your 2013 Energi engine speed where Motor A stops and changes direction is approximately 1760 RPM. Happy holidays
@@WeberAuto Thanks for the ICE rpms where MG1 stops. The next time I've got the car I'll try to do some experimenting and see if there is a noticeable fuel economy difference between positive power split mode (slightly lower speed/ICE rpm ratio with MG1 spinning "backwards" and increasing the ICE rpm) and negative power split mode (slightly higher speed/ICE rpm ratio with MG1 spinning "forwards" and reducing the ICE rpm). I also wonder if it will allow the car to cruise with MG1 stopped (maintaining the speed/rpm ratio to 65mph/1760 ICE rpm). One odd "feature" I have noticed is when cruising at ~65 mph if you switch from "D" into "L" the engine rpm drops as if it is attempting to operate in negative power split mode (using the larger MG2 traction motor to generate power instead of the smaller MG1). Switching back into "D" causes the engine to rev back up as if it is attempting to operate in positive power split mode again. At first this seems counter intuitive (lower engine rpm in "L" and higher rpm in "D"), but by using MG2 to be the power generator instead of MG1 this means the larger motor generator is already being used and this likely allows the car to have quicker response to and more regenerative braking as well as be more capable of reducing hill descent speed and these are the reasons to use "L". This lowering of ICE rpm only happens at highway cruising speeds close to the MG1 transition between spinning forwards vs reverse. At both lower (less than roughly 55 mph) and higher speeds (above roughly 75 mph) the ICE rpm stays the same between "D" and "L". I assume that 1760 ICE rpm correlates to 65 mph.
@@WeberAuto , I think Slider68 is approaching the problem correctly. For torque to go from the ICE to the final drive, torque will be required at MG1. A common sense way to picture it is that the planetary gearset functions like a rearend differential --- if one wheel is on ice, that wheel just spins and the car goes nowhere. Unless the car is coasting, MG1 will always be either acting as a motor or generator. It is incorrect to calculate an RPM for MG1 while ignoring the forces at work --- just as it would be wrong to try to calculate the RPM of a wheel on a slippery surface while ignoring the difference in traction between the wheels. Picture a traditional car with an open differential: You can't just say that we know (1) the engine RPM and (2) the speed of the wheel on dry pavement, then do the math for gear ratios to compute (3) the speed of the wheel on the slippery surface. The engine RPM and speed of the wheel on dry pavement will change from your assumptions based on how slippery the surface is. In other words, the math for the gear ratios in the planetary gearset can only tell us the RPM of MG1 after the torque from the ICE and the torque going to the final drive are considered.
Mr John Kelly,Thank you for your job,for your lesson.I think you need work a some technician University. You are the best teacher. I'm sure if you were my teacher I would be the most professional repairman. But I'm only professional Truck Driver.
You're just amazing ! What a treat - Wish I was as clever as you. I found your video fascinating in so many different ways. Many thanks......all the way from London !
Amazing stuff, Professor, verry well explained, fantastic camerawork and a very clean workshop! Have not seen this in Europe (Belgium). As a elektrician I watched a lot of your video´s. I own a 2021 corolla 2.0 with a P711 transaxle wondering what differences it has with a P610 or P710. With the highest regards.
This guy disassembled this whole trans axle, labeled everything, made sure he know how everything worked, buttoned it all back up and only then started filming. A lot of extra effort to make the video better, easier to follow and accurate. Awesome
Thank you very much
Dear Professor, as a mechanical automotive engineer and the owner of a Gen III 2010 Prius (with 305k trouble-free miles) and a new 2018 Gen IV Prius, I am in awe of the quality of your work. The quality of your videos and the clarity with which you explain all the aspects of the Toyota hybrid powertrain are unparalleled. Thank you very much and congratulations to you and your team!
Thank you very much!
The presentation really gives you an appreciation of the quality of build and the absolute intelligence of the design
I have a 2016 prius. Im in love with this machine.
Alberto couldn’t say it better myself
He is pretty annoying right..
You really are a teachers teacher. At 1:52:43 you describe the continuously variable part of the transmission as the interplay between the engine and MG!, and you do it almost as a casual aside. That is such a genius idea and yet you say it as if it were just an afterthought. You are the most gifted explainer I have ever come across. You have my highest regards.
Dear John, congratulations for this beautiful video. The World needs people like you. Regards, Marcelo.
Thank you very much! Have a good day!
totaly agree
This guy is a total boss. I admire his teaching style and depth of knowledge. Full respect dude
I could have lived the rest of my life not knowing differential components of my car are pressed together. Now I’m gonna think about that every time I step on the gas.
Love these videos.
LOL! Thanks for watching
Hi Professor Kelly,
I just wanted to take the time to say thank you so much for these incredibly detailed and informative videos that you post. Automotive mechanics has always been something of a passion of mine (I have a 1996 Honda Accord EX-V6 that I baby and am always looking for something to get to fix on it) but pursued a degree in I.T. which is what I am doing now, as much as I want to pursue a career in your field.
If I am not watching a video of yours as intently as possible I also find the way the videos are designed to be a bit therapeutic and make sleeping a breeze! Lol! Thank you so much for these videos again!!!!!
Thank you and best wishes!
Excellent video, really appreciate the depth that you went in to.
At about 55 minutes in, a comment was made that MG1 has 5 lobes on the resolver, while MG2 has only 2. It looks like MG1 has 10 magnetic poles, so five North/South pole pairs. MG2 looks like it has 8 magnetic poles, or 4 pole pairs. So for every lobe on MG1, they know where the North poles of the rotor are. If they had only two lobes on MG1, they would only know that a North or South pole was at that location, because one lobe might point at a north pole, while the opposite pole might point at a south pole.
For MG2, they know that a north pole is located by either the lobe, or the valley between the lobes.
I was able to find the magnet configuration in a paper from Toyota engineers that describe the P610 improvements. The configuration is much like a bent staple, and what seem like tiny magnets are indeed just the two side magnets at an angle terminating around that point. The three magnet configuration was designed to be "closer to the fundamental harmonic thus making the motor more quiet". The paper is titled "Development of New Motor for Compact-Class Hybrid Vehicles".
Thank you so much for this video! I just love learning anything I can about this marvel. Your videos are a priceless contribution to the world of engineering.
You are fantastic! I was a military instructor for mechanics for 6 years during my tour in the army and I have to say you are a great teacher. I love all your videos. You are Bob Ross for mechanics!
Professor Kelly, i own and drive daily a 22 Prius Prime. I have owned both a gen2 and gen3 Prius prior to my current car. I have tried through the years to purchase cars later in their cycle (buying a 22 instead of a 17) because the engineers and QC at Toyota have had time to deal with any issues and provide the most reliable product within that generation. Ive purchased the technical manuals for each car and applaud both your accuracy with specifications as well as your ability to teach about something so complex. You present without frills or drama and make it so easy to understand. You have contributed to my better understanding of these products and their serviceability. More importantly, all your videos inspire me to learn more. For this i am truly grateful, thank you. As a mechanic i wanted also to reitterate for viewers that your unique and detailed knowledge of the products you dive into could not be obtained without taking them completely apart and putting them back together again. Its risky work and want to thank you also for the huge investments that you make of your time to do this. I feel you truly have fulfilled your purpose here on earth and hope you may continue to do so, helping so many of us to better understand these cars.
You’re a good man and instructor, thanks. Something about this p610 is different from an older model, there is no internal drive chain, didn’t see one in this video, that’s a good thing, eliminated is the word I like to use, simpler is good engineering
I'm a qualified tech with Toyota training specific to the HSD. I also reconditioned battery packs professionally for several years with success. I can honestly say I've learned more from this channel than any other source...excellent work and mountains of knowledge...appreciated.
can you fix my prius??? just kidding. my prius is a beast.
Professor Kelly, you are amazing. If I had only known of you and your school years ago... Thank you for your generosity and commitment in making all these videos. If I was younger I would be applying for next semester.
Thank you very much!
Professor Kelly. I’m 72 years of age I’m in Australia and u would call me here a bush mechanic (a self taught from the age of 19 years old. )Your explanations of that engine and electric gearbox was awesome. I would like too know how to see more of your videos. I also noticed how nice and clean your workshop is .
I'm not a mechanic and was able to understand everything you were explaining. Thank you for sharing all this detail and information!
Thank you!
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I'm not machanic but I have interest to learn , please how can I learn
@@iskaarak6503 watch more videos, get a car to wrench on. Getting familiar with any car and it's operations will help with your knowledge of any machine. Went from no car knowledge to comfortably changing my clutch on my own with only 2 tiny jacks. After that I fixed the electric seatbelt motor without any issues or any looking up for blow ups or forum help..
@@WeberAutotö
Die sind auch
You are one of those few guys one stumbles upon, who knows their sh*t ,as we used to say. Interesting to see someone use a somewhat monotone delivery, no crazy graffics, or pontificating.. just brilliant dry analysis of fascinating tear downs. Keep it up you're teaching more than 99percent of academia.
Thank you very much!
Dear Professor I'am a MV Lecturer at croydon College ,London my name is Derek that was the most informative detailed strip down, excellent explanation of component operation, we will using your website to comp[ete our CPD at work. Love your workshop.
Excellent work sir. So nice to see machines when they are new. Having spent countless hours struggling with frozen fasteners and greasy grimy components it’s a real pleasure to see them in such a clean environment. Makes a great case for taking the time to keep vehicles clean and degreased.
Thank you very much!
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Wooo, best teacher i finally understood how my p610 works. 100% understood. What how and why my prius prime does something. Thank you for all. Time, work, research, math... i did not miss any second !
Seeing someone in a wheelchair disassemble & explain the transaxle of the Prius was super inspirational. Cool technology! Nice video! Nice and detailed!
Thank you!
Wheelchair or wheelchair not, excellent job. All his videos so far are excellent. I can’t believe the lengths he went through to make this vid. But I like his curiosity.
I stumbled across this RUclips channel while searching for something to help me study for ASE auto trans recert. You can't pay for classes this good. Our manufacturer classes that last several days aren't as in depth as what this guy does in an hour or 2.
Nice video, I'm impressed by this tansaxle. It look and feel like there is not cost cutting in this.
The MG2 stator is very impressive, it seem to be built like an high end industrial motor. I guess the prius 4 will continue the legacy of being one of the most reliable car on the planet.
Thank you! I am sure it will.
zeuss194 And gas saving on the planet in iraq or midfle east gas is only 10 cents a gallon
John, it was a pleasure to follow your clear, captivating and professional presentation.
Thank you!
This was the most comprehensive review of anything I have ever seen.
Thank you!
I agree. WeberAuto should be given the award for best teacher ever.
Thank you very much for your hard work and vast amounts of time making these videos. I have been an automotive tech for 30yrs. now. You do a fantastic job describing/visualizing theory and operation. Im certain people with little vehicle knowledge can, at the very least, understand the principles put forth here. I work mostly on Toyota products and have many Prius repairs to my credit. I have consistently seen gen 2 Prius with 300k and up. Personally, I am whiteness to a gen 2 that made it to just over 800k of service with a transaxle that was never serviced (except for fluid changes). No leaks, no quirks, it functioned perfectly. That is simply amazing. As an owner of a gen 2 and 3 Prius I give Toyota and its engineers an lot of credit for their work 30 plus years ago when they started working on this radically different design. They went out on a limb back then. Toyota had to make them do more then just work for a little while(planned obsolescence). Those units had to be reliable and go the distance in order to sell their new technology to the masses. I think your videos show how they achieved this. I am lucky I can point customers to your videos when they ask me how their Prius transaxles work. Thanks for educating.
Thanks for sharing and thanks for watching!
you sir are a public treasure, I very much appreciate these videos and you have one of my favorite channels
Master mechanic and painter here, by far the best automotive videos and thorough explanations , thank you 🙏🏻
Wow, thanks!
Impressive expertise! Great to see the job being done and taught by those who they know what they are doing
Thank you!
Thank You Professor Kelly. You have this incredible capacity to explain a complex process in just simple words. Felicitaciones!!!
Maestro American must be proud of having you as part of their country. Gracias senor
Thank you!
The quality of the video is just amazing you guys should do a TV show or something man this is this stuff is amazing
Thank you very much!
@@WeberAuto you guys are the best
Wow! I'm a NATEF master instructor and have my own channel, and you have blown me out of the water! Thanks so much for this, and I will be subscribing and following you.
Thank you very much
John, I waited for this video to upload before releasing our Prime review and have included links to this video along with links in video to your content about the P610.
Thank you very much, I will have to check it out.
WeberAuto .... love your work used to work on Ford and Nissan 35 years ago find how you present information exceptional.
😘😘
@@tonys8243no
@@WeberAuto oookp
The configuration of the magnets are in a halbach array arrangements it's purpose is to make the emf polarities of the back of the magnets concentrate towards the front as to provide a substantial amount of force facing the stator it is a technique also used in particle accelerators
That is good to know! Thanks for the feedback!
Excellent video, great camera work, very knowledgeable. Thank you so much!!! I just bought one for work road trips and I love it!
I LOVE this channel! I think you will have a difficult time finding any videos that cover this type as content as clearly, competently & completely as they do here. I want to thank the channel owner & the gentleman in the videos for providing such high quality videos! It is so nice to be able to see how things work & get a great explanation of how & why they do what they do.
Thank you for what you do!!!
Those castings are a work of art!
Incredibly well done. Sound, camera work, comment all very clear. Loved it! Thank you!
Thank you!
At 51 year old, you give the idea of going back to school.... if all the teachers are has good. Love your videos
Great explanation of this power train that I’ve always wondered about.
Thanks sincerely for uploading this post!
You rock, the best video and break down of the video description of you video I have ever seen. Good work man.
Thank you very much!
Excellent video. This is exactly what this country needs: more training and understanding leading to the right to repair.
Thank you very much
You are a legend John, that was extremely well explained, concise and precise. Subscribed.
Thank you very much!
This blokes knowledge is on another level. Really well presented and informative 👍👍👍
Thanks for watching
What an amazing video. Extremely detailed. Never seen such detailed video like this. I have more respect for the Toyota prius.
I like the organization of the Prof. The explanation is really a show. For us here in Brazil these kind of videos are priceless. full of details. Lucky the guys, that have the chance to participate of these "classes" with the Prof.
57:09 props to you for pulling out a new transaxle just to create a RUclips video!
The best teaching video I ever come across, I like the parts go to zip lock bags, so that easily organized and easy to put it back.
Thank you very much for an interesting video that really explains how it all works. Fascinating understanding of how the combustion engine and the electric motor cooperate.
Thank you!
WOW. John....you are the man. Thank you so much for sharing all of this knowledge in such a useful and organized format. YOU ARE THE MAN SIR!
Thank you very much for the video. Well organised, professional introductions and advice and slow and clear speech that I can not miss any detailed explained. Great work, keep up good work. Thank you.
Thank you!
I am impressed at the fact this is a brand new transaxle you plan to reinstall into the Prius
Thank you! It has been a lot of fun
Excellent video, thanks for taking your time to make it! Not to mention marvelous piece of engineering
Thank you!
Am considering purchasing a new Prius Prime, loving these details as a previous Quality Control Tech for 40+ years
What an interesting and well put-together video. It must have taken a lot of work. Thanks!
Thank you!
I love how hes just taking it apart to show eager minds the technology and right skills
Thank you very much
I love that it has so much tech, yet still uses that old fashioned looking open diff, I figured these would at least have worm gears. I’m glad I found your channel, man I might need to come to your school….looking at getting out of truck driving and going back into these newer electric drive vehicles. Gotta stay with the times.
Great Job of Breaking Everything down!! Thank You !!
Thank you! it was fun
Excellent video. You definitely appear passionate and extremely knowledgeable. Thanks for teaching me about this transmission.
Thank you!
Прекрасная речь, великолепная картинка, чистота как в операционной. Жаль, что я не понимаю английский в полном объёме.
Спасибо
Thanks very much for the excellent, high quality videos. I've learned a lot about hybrid technology from your production.
Thank you!
Wow, just found these! Thanks for taking the time to produce these wonderful videos. I especially appreciate your details, decals and depth that you have gone to document the interior components. This is really helpful for the daydreamers (myself included) in integrating these now more readily available hybrid components in motorsport applications.
Really looking forward to checking out the DC BUS and VFD components in the drive control box next, Cheers!
Thank you very much!
I really like your videos. Very professional indeed! Looks like this is the best education about cars, that you can buy with big money, but no! This is free, and maybe even better, than some of these technical schools with tuitions. I`m just very impressed about this amount of knowledge. good work, keep going!
Thank you very much!
Dear Professor,
thanks for your great video!
The reason for the number of resolver poles is that a resolver can not provide the absolute rotor position. Within one mechanical revolution its position signal repeats itself by the number of pole pairs, so you have an uncertainty of 360 deg divided by the number of resolver pole pairs. For the field oriented contol of the inverter it needs to know the relative position of ANY pole pair of the machine. To ensure this, the pole pair number of the resolver must match or be an integer division of the pole pair number of the machine. The MG1 has 5 pole pairs so the resolver must have the same. The MG2 has 4 pole pairs, so resolver pole pairs could be 1,2 or 4. Due to mechanical imbalance, 1 is no option.
Great information, Thanks for your feedback
Forgive my oversimplified thought: Would it be correct to say that the Resolver provides position reference to allow Motor Movement between poles AND the Resolver position reference minimizes an uncommanded motor movement which would otherwise be in either direction of rotation. # Uncommanded motor movement?
@@anthonyrstrawbridge I'm not sure if I got your question right. The inverter needs to know the relative position between the rotor poles and the stator winding. Based on this position information, the inverter can inject the right current amplitude and phase to generate a given torque as well as rotation direction. Please, feel free to ask if this doesn't answer your question.
YOU ARE DOING EXCELLENT JOB VERY GOOD INFORMATION GOD BLESS YOU AND THER IS FEW PEOPLE LIKE YOU SIR
Nice to see that Toyota provides an easy way to check/manipulate the fluid. Not having these is one of the most annoying recent trends
And yet in 1987, Toyota had a very accurate and reliable engine oil level sensor for the engine in the van that I had.
That was 34 years ago.
Why isn't a similar sensor installed here.
It creates great peace of mind to know for sure what your level is.
Congratulations on the excellency of your explanation
I'm no mechanic, but I love watching and learning, thank you.
I just took delivery of a 2023 Rav4 Prime SE, and drove it 3,200 miles from a Toyota dealer in Baltimore, MD back home to California. The P-810 transaxle is awesome! The Rav4 Prime is a heavy car, something like 4,300 pounds curb weight, yet the powertrain (18kW battery, ICE, MG2, and MGR) lets the car climb 6% freeway grades with no feeling of stress of strain at all. On the downgrades, the regen braking holds the vehicle at whatever speed you set the cruise control at, perfectly. No need to touch the brake pedal at all. It was a joy to drive, the only (slight) flaw being that I'm a bit on the tall and heavy side, and I might have wished for a slightly larger driver's seat that supported my legs more comfortably. The transitions between EV and HV modes are so smooth and quiet, that they are all but un-noticeable, same as in my 2019 Prius Prime, and the 2.5 liter engine is so well insulated in it's mounting, that it's hard to hear even at 3,500 rpm. At normal cruising, 1250 to 1800 rpm, it's virtually silent. Great job Toyota, and thank you Professor Kelly for all these deep dive videos on the HSD transaxle, to help me visualize what's happening under the hood, so that I can be a better driver and get the most performance out of my Toyota HSD, while at the same time protecting my investment.
Amazingly detailed video. Best transmission videos on youtube.
Thank you!
Thanks
Thank you for your kind donation! Have a good day.
Thank you for an excellent series of video presentations!
On the planetary gear set I want to add:
The sun gear is not part of MG1 shaft in all versions but rather splined to it. The planets carrier shaft is connected to the engine crank shaft via the dampening clutch.
Both these elements have some radial flexibility which will not be there without, this slight radial 'freedom' is essential IMO for the operation of the set, components can be self-aligned by load exerted so the load is equally distributed into 4 (4 planets, 4 sun teeth, 4 ring teeth) or 3 in case of 3 planets set. This accurate self alignment cannot be achieved with rigid construction certainly not in the long term.
This is IMO also the reason (or one of the reasons) of adding a spline adopter in the P610 - to give extra radial flexibility.
One of the beauties of a planetary set is being small and compact for the load it is rated to.
Great Feedback! That makes sense. Thank you.
Thank you for a most informative video; I didn't realize the Toyota plugin hybrids were so complicated.
Thank you!
Yeah, it’s not that complicated. Fewer moving parts than a traditional transmission.
you, sir, have a really nice workshop there. and of course a very impressive knowledge.
you just showed me, this part of my car works. awesome!
Excellent presentation with a lot of details not found in the TIS publications. Thank you!
The maintenance manual diagram of the one-way clutch suggests a subset of the spring-loaded teeth are engaged. Speculation on my part but engaging the one-way clutch probably needs to be done gently to avoid over stressing the teeth. The MG1, five lobe resolver cam may make that easier without having to increase the resolver exciter frequency.
Thank you! I described the engagement of the one-way clutch partially incorrect. The ICE is rotating clockwise while running, as it slows to a stop (under 400 rpm, the teeth are released from their centripetally held positions and start ratcheting. When the engine stops, the teeth are fully released and will hold the crankshaft from rotating backwards. Regarding the 5 lobe resolver cams: After shooting the video I discovered that the 5 lobe resolver cam is used to keep track of the position of the 10 magnetic poles of the MG1 rotor. the previous rotors only had 8 poles. Thanks for your feedback.
Thank You so much for such a wonderful explanation. I don't think we can get it anywhere else....
i want to thank you for making these videos i am learning so much you are a amazing speaker thank you very much professor for your time
Hello and thank you for your time to teach/show us your knowledge. We'll explain video module. God bless you and I'll be looking forward to more videos. Happy holidays to you and your family
THANK YOU JOHN, MUCHAS GRACIAS DESDE MEXICO POR ENSEÑAR LA TECNOLOGIA ACTUAL, ¡ MUCHAS BENDICIONES WEBER AUTO !
Thank you!
This guys the Best :)
Thank you!
Super informative, Excellent video production.
Thank you
Thanks very good teacher,like the teacher I had 45 years ago when I left school and became a mechanic. 🚘👍😀
Thank you!
Thats why I love prius and toyota hybrids, it might be not a prettiest car, or most efficient or fastest but its a damn clever design, they simplified lots of things with this transaxle while car still have different modes of operation, variable transmission but nothing really "shifts" there, love it! Cant wait to see what 2019 rav4 hybrid will bring, it should be same design but scaled up in power, tested 2017 rav4 hybrid and loved it but it still had same issue as my 2010 prius as you couldn`t drive it faster then 40mph on electric only power, but new prius defiantly can (I actually managed to be more efficient with rav4 then with my prius as you can use electric engine in broader range and accelerate using mg2 alone and mg1 charges battery way faster then my prius does so ICE engine is barely engaged in overall trip
Great channel , thanks for all the information!
Thank you and thanks for your feedback.
I have a small question thought , from your videos I learned that 3rd gen prius high voltage battery can be charged when the car is stationary , but I usually turn car off or dont stay for long and car only charges to 3-4 bars and then shuts ICE off. Question is in what conditions prius can charge the battery the fastest while the car IS moving? My conclusion is - during hard acceleration in PWR part of ...hybrid-meter... is it correct? Its just car goes quite poorly when you have 2-3 bars of battery charge left (it doesnt really allow you to use EV mode when battery is depleted) and I want to keep it at high charge when I get to slow speed areas so I can use EV mode more freely
Many thanks!
The battery control system does not want the battery charged any higher than 50% during normal operation. This is to preserve battery life. When the vehicle is stopped, it will cycle between 40% and 50% with the ICE. Any higher charge will typically come from decelerating and regenerative braking. See ruclips.net/video/2kM1-UL3yN4/видео.html I have not added sound yet, but you can see it cycle with scan tool data.
That is really interesting video , thank you, so it seems that battery indicator doesn't really represent full battery charge range but rather from 20-25% and up till 80% I assume, I have exact same prius, would be interesting to see what it does while moving as I saw some interesting modes, (1) like when its cold, car can move on electricity but will turn on ICE to heat up whole system, (if its really cold it can disable regenerative braking for a minute or two) while it seems ICE wont rotate wheels themselves or so it seems, if you try to accelerate at about 2/3 ECO bar range during this time it seems like engine wont rev much ,acceleration will be very silent and smooth! (I know its bad but only do so in emergency acceleration, still very interesting, usually car revs up fairly easy),(2) if you get into ICE range mode but then slightly depress gas pedal and go into electric range you can get fairly good MPG at low speed with ICE on (car can still accelerate at times tho),(3) in PWR range if you press gas pedal fully you can experience acceleration boost (like from 90% pressed pedal to 100% , there is a kick in acceleration) I wonder what this is, battery does not deplete as in 4th generation during such acceleration, it seems like either ICE operates in "throw in all petrol you have, there is no time for been economical!" or mg1 helps alot or whole system voltage rises up to a different level (5) also in EV mode you can press gas pedal till 1.5 electric range until it drops EV mode (or until you reach 22miles/h ) and it accelerates noticeably faster! sad thing only that 22mile/h is a fairly low speed limit when you know it can go till 35mile/h on electricity alone, even tho it will take some time....Cheers :)
I have car for 4 years but I still find some new features every now and then! hah! :D
Excellent video. Really enjoying this. I have a 2016Prius C that weighs about 500-800 pounds lighter than higher models. Better MPG and acceleration.
Thank you and thanks for your feedback!
Yeah, you're right! It's cool to know the inner workings as mentioned. I did appreciate a lot the nice video.
Congratulations.
Regards.
Thank you!
What a beatiful video Thanks. But a small correction for PSD torque distribution at all ICE,MG1 and MG2 at same RPM 3240. The torque always will be distrubuted to MG1 at a ratio of %27.8 ( can be calculated from gear ratios). If they all same RPM then power will be distrubuted to MG1 at the same ratio %27.8. On the other hand, if MG1 RPM is 0, then all power will be transfered from ICE to MG2(to final drive) even if torque ratios are constant at %27.8 for MG1. Don't forget, at 0 RPM, torque is still there, but power transmission is zero...
I agree about constant 'steady state' torque distribution in the planetary gear set (and the need to consider rpm to calculate power distribution under different circumstances). In direct drive, neither all the torque nor all the power from ICE flows to the wheels, as pointed out by sedanet. It is a great video of lasting value, and I wonder if it can be edited to remove this important misconception.
@@RobertBirch-h6vdirect drive can be possible. all the power can be transfered from ice to wheels if mg1=0(except frictinal losses)
excellent video mate, shocking how tiny the motors are!
Thank you! Yes, I was also surprised.
Some have huge motors..
just taking it appart and getting it that clean and labeling it is incredible.I thought it was a shop prop not out of a running car.
Thank you! It went back together and worked great too! See ruclips.net/video/ErC7MpWGsgI/видео.html
Awesome video! I find it is the best to watch it at 2x speed.
Thank you, I do too.
Thank you sir for doing this video. I'm now studying in germany, for somehow, I think I decided to start learning about the Auto during watch this video.
Thank you!
An excellent video. Dear John, congratulations!
Thank you for this excellent video explaining the details of 4th gen Prius transaxle .
I really enjoy your thorough explanation of the hybrid power trains, we have A 2019 Toyota Highlander hybrid which I would imagine Is a larger scale version of the Prius, great video thank you Professor
Awesome video. One thing to keep in mind when the vehicle is cruising down the road at higher speeds is in order to power MG1, which effectively varies the functional gear ratio between the engine and wheels, that MG2 will be generating the electrical power ("stealing" mechanical power) required to power MG1. At lower cruising speeds where MG1's rotation direction is the opposite (but torque direction hasn't changed), now MG1 operates as a generator and the excess power (at constant low speed cruise) is now fed into MG2 to help propel the vehicle.
I'm not sure what actually happens at the optimal cruise speed where you want MG1 to not spin (as you mentioned), but with it not spinning it can't generate any power so my guess is MG2 continues to generate a small amount of electricity which is used to "stall" MG1 against the engine torque. Interestingly, if you think about these power split cruising modes you'll realize that power is always being wasted by the inefficiency of generating power in one motor and feeding it to the second motor in order to create the optimal gear ratio for the engine. With the ideal gear ratio a regular automatic transmission with locked TC (or manual transmission) will always be more efficient for cruising at a constant speed on the highway than these power split transaxles are.
I've often wondered why there isn't a mechanical brake on MG1 and gearing selected to allow the engine to operate at an optimal rpm for highway cruising to enable optimal efficiency at 55-70 mph with zero electrical power being transferred between electric motors.
Thank you! MG1 does not help propel the vehicle except on the Prius Prime (plug-In) in EV mode. It requires a one way clutch at the flywheel to prevent the ICE crankshaft from spinning backwards. MG1 is used to charge the HV battery and vary the engine torque contribution to MG2. A mechanical brake is not needed to stop MG1, it stops on its own when changing directions of rotation. That is typically around 2340 ICE rpm at 65 mph.
@@WeberAuto I assume with your first sentence you are talking specifically about EV only mode. In hybrid mode MG1 helps to propel the vehicle at higher speeds with all of these Toyota/Ford hybrid systems (whenever the ratio of vehicle speed to engine rpm is greater than 65mph/2340rpm for the system you were working with). With our C-Max Energi this is known as "Negative Split Mode" and in the Ford manuals they also talk about it as "Highway Cruising Mode". At lower speeds MG1 and MG2 switch roles while operating in "Positive Split Mode".
Yes no brake is needed to stop MG1 - but I probably wasn't clear in what I was trying to say. The issue (inefficiency on the highway in hybrid mode) is that electrical power (positive or negative depending on relative speed/rpm) is still required to generate the torque at MG1 needed to balance the engine's torque. This is true even when MG1 is stopped (eg. ICE @ 2340, speed 65 mph) and this electrical power is generated for MG1 using MG2 (when not discharging the battery). If no power was sent to MG1 the engine would essentially freewheel and not be able to do anything other than rev up.
Requiring MG2 to generate electrical power so it can be sent to a non spinning MG1 is the current solution for that particular scenario but if instead MG1 had a brake designed into it then while cruising the brake could simply be engaged and MG2 could simultaneously stop generating electrical power (stealing mechanical power from the system) and this would result in improved highway efficiency and fuel economy on the highway. The overall gear ratio could be further optimized if 2340 rpm isn't ideal for 65 mph (although that sounds about right for a small sub-2 liter engine).
Interestingly if you look at what Chevrolet did with their Voltec 2 Hybrid system they have a mode that enables exactly what I am suggesting (I believe the Voltec 1 did too but haven't confirmed for certain). The current Volt can, while cruising at certain speeds, connect the engine directly (through an appropriate overall fixed gear ratio) to the wheels and both MGA and MGB can completely shut down. The volt also retains the ability to use a "Negative Split Mode" and "Positive Split Mode" to take power from MGA and send it to MGB and vice versa to optimize engine rpm vs vehicle speed, but at typical cruising speeds it can further improve efficiency and run 100% on the ICE with a fixed drive ratio by engaging the two clutches. While driving in this mode MGB can still be used to supplement mechanical power if needed (drawing on the battery) or can be used to top up the battery as a generator. The Voltec 2 also has a mode where the engine sits stationary against a sprag clutch to ensure no reverse rotation that it can use both MGA and MGB to power the vehicle (similar to the new plug-in Prius).
Compared to the Voltec 2 Hybrid system, our C-Max Energi's system looks quite primitive. On the highway our fuel efficiency is quite poor (7 to 8 l/100km) and having a direct drive mode would be a nice addition (although aerodynamics are likely a big part of the highway economy). Our city fuel economy is very good though and due to rush hour being so bad here we typically average 2.5 l/100km overall during a 100 km daily commute (including a daily battery charge which gives us about 25 km of EV range these days after 150,000 km; when new we got 40+ km of range; best was 55 km).
Do you happen to know with our 2013 Energi at what ratio of vehicle speed to engine rpm MG1 stops turning? I've always intended to dig through the specifications, work it out, and experiment with driving the vehicle at those speeds/rpms to see how the system handles it and how the fuel economy is influenced by positive split vs negative split vs the stalled MG1 negative split state. I've also wondered if it will allow MG1 to remain stalled for long. The computer may deliberately transition through forward/reverse MG1 direction without it remaining stalled for long (MG1's coils being used at stall may eventually get hot so it may not allow it).
Thanks again for the video and information.
@@Slider68 Thanks for the information. Your 2013 Energi engine speed where Motor A stops and changes direction is approximately 1760 RPM. Happy holidays
@@WeberAuto Thanks for the ICE rpms where MG1 stops. The next time I've got the car I'll try to do some experimenting and see if there is a noticeable fuel economy difference between positive power split mode (slightly lower speed/ICE rpm ratio with MG1 spinning "backwards" and increasing the ICE rpm) and negative power split mode (slightly higher speed/ICE rpm ratio with MG1 spinning "forwards" and reducing the ICE rpm). I also wonder if it will allow the car to cruise with MG1 stopped (maintaining the speed/rpm ratio to 65mph/1760 ICE rpm).
One odd "feature" I have noticed is when cruising at ~65 mph if you switch from "D" into "L" the engine rpm drops as if it is attempting to operate in negative power split mode (using the larger MG2 traction motor to generate power instead of the smaller MG1). Switching back into "D" causes the engine to rev back up as if it is attempting to operate in positive power split mode again. At first this seems counter intuitive (lower engine rpm in "L" and higher rpm in "D"), but by using MG2 to be the power generator instead of MG1 this means the larger motor generator is already being used and this likely allows the car to have quicker response to and more regenerative braking as well as be more capable of reducing hill descent speed and these are the reasons to use "L". This lowering of ICE rpm only happens at highway cruising speeds close to the MG1 transition between spinning forwards vs reverse. At both lower (less than roughly 55 mph) and higher speeds (above roughly 75 mph) the ICE rpm stays the same between "D" and "L".
I assume that 1760 ICE rpm correlates to 65 mph.
@@WeberAuto , I think Slider68 is approaching the problem correctly. For torque to go from the ICE to the final drive, torque will be required at MG1. A common sense way to picture it is that the planetary gearset functions like a rearend differential --- if one wheel is on ice, that wheel just spins and the car goes nowhere.
Unless the car is coasting, MG1 will always be either acting as a motor or generator. It is incorrect to calculate an RPM for MG1 while ignoring the forces at work --- just as it would be wrong to try to calculate the RPM of a wheel on a slippery surface while ignoring the difference in traction between the wheels. Picture a traditional car with an open differential: You can't just say that we know (1) the engine RPM and (2) the speed of the wheel on dry pavement, then do the math for gear ratios to compute (3) the speed of the wheel on the slippery surface. The engine RPM and speed of the wheel on dry pavement will change from your assumptions based on how slippery the surface is.
In other words, the math for the gear ratios in the planetary gearset can only tell us the RPM of MG1 after the torque from the ICE and the torque going to the final drive are considered.
Mr John Kelly,Thank you for your job,for your lesson.I think you need work a some technician University. You are the best teacher.
I'm sure if you were my teacher I would be the most professional repairman. But I'm only professional Truck Driver.
You're just amazing ! What a treat - Wish I was as clever as you. I found your video fascinating in so many different ways.
Many thanks......all the way from London !
clean and labeled, your professional attitude shines!
Thank you for a very informative and thorough explanation !
You are an inspiration , thnx again .
Thank you!
Amazing stuff, Professor, verry well explained, fantastic camerawork and a very clean workshop! Have not seen this in Europe (Belgium). As a elektrician I watched a lot of your video´s. I own a 2021 corolla 2.0 with a P711 transaxle wondering what differences it has with a P610 or P710.
With the highest regards.