Providing the Munro crew with an example of their latest product for a public critique shows that the people at Rivian are proud of their work and confident in the quality of their product.
Wow! Scott's description of the Rivian motor/differential/inverter is the most complete and logical of all your drive train analysis. It makes so much more sense when explained as an integrated package. Now, can we see a similar analysis of the Ioniq 5's motor teardown of 4 months ago? Thanks in advance!
The solenoid valve on the plate cooler allows them to more rapidly bring rotor oil up to temp. Thereby achieving optimal operating temp/viscosity in cold weather startup environments.
Of all the Munro video presentations this must be one of the very best. Every clear explanation was then represented with equal clarity by the perfect visuals. It had a relaxed pace and didn't appear scripted in any way ... but surely it must have been ... you can't be that good without careful planning! The editing was kept to a minimum and was almost invisible (as it should be). This was a fascinating dive into the technical features of the Enduro motor/drive unit. 10/10.
Thanks Scott for the clear and concise overview of the drive unit. It is great to see some pretty savvy engineering coming out of a young company, Rivian.
Fantastic video. You're one of the top presenters in the stable! Can you please do an episode that does a side by side comparison of the latest drive units you have from Rivian, Tesla, Lucid, Ford, and the rest?
Those who might not know, we're seeing an incredible display. Engineering, knowledge, human ingenuity - sure. But those pieces that Scott is showing us around, are ALL HEAVY AF. Dense metal parts. Scott is strong. Like GOAT strong. I'm amazed, and frankly super-impressed. Brains and brawn.
Nice to see Rivian offering more sane HP levels with this setup. We've lost focus lately sacrificing efficiency on the 0-60 Altar which is part of whats driving the need for higher kWh batteries. A more efficient unit with low enough power requirements to get equal or better range from lower kWh batteries would be a refreshing change. Lower HP means lower wattage requirements, less waste heat, lower cooling requirements, less time to charge and lower cost per mile. At more reasonable HP levels will a liquid cooled motor really be needed? If not then all that complexity/weight/cost can go away. When I started driving anything less than 9 seconds 0-60 was sports car territory and not really needed for merging on the highway, getting to work or for a grocery run or in other words your daily driver. Even the original Nissan Leaf is higher performance than most muscle cars from back in the day and more than is really needed. When I drive an EV I want to see 5 Miles per kWh or better and not this downward spiral to 3 or less. Best!
Wow!!! What a mind-blowing presentation. A stunning exhibition of competent consummate clarity, completeness, comprehensive communication. Munro's videos are great but this one tops them all!
Wow, that was a phenomenal presentation. Clear, concise, language a non-engineer can understand. Organizing your thoughts into an on-camera public speech on a highly technical subject is NOT easy! Congratulations, Scott.
Holy... I bet you're next in line for shotgun at ML. You're nailing all your presentations and your energy is perfect. You know your stuff and it shows. Congratulations and keep these gems coming.
Doubly Impressive! Rivian engineers are the "real deal" and did a great job. Scott is articulate, detailed, concise and has a flowing logical narrative progression, which is better than 99% of engineers and professors. Congratulations to both. Hopefully Ford and GM are talking notes, though anything they learn will take more than a decade to implement....badly. 😂
@@golfish8589 There is no such thing! Whenever GM starts serial production at an established price, then we can talk about its wonderful features, or not. GM has been making BEV announcements for years with little to show for them in terms of vehicles made and sold. The only BEV they made, the Bolt, even though it was the least expensive BEV, sold poorly, even with GM losing $15,000 for each one and has been now cancelled (though resurrected on the latest press releases.). The Ford F150 Lightning, which is at least in production, and can be evaluated, is not selling well. The Silverado is so far just PR. Just wait for reality to catch up with the Hype, and then make comparisons. What if the Silverado meets all your expectations, but is $150,000 (with dealer premiums and a 2 year waiting time)?
Munro has industry leading reputation and privides people interested in EVs, but unfamiliar with the particulars, a great deal of information about the quality and design of the products on the market. You provide an excellent service to us all!!!
Thank you, Scott! Great presentation, and you explained it in a way that a doofus non-engineer such as myself could follow it. Well done, and way to go Rivian--seems like a really effective, well thought out unit, and I am sure it will get better as time rolls on.
Great video. Very clearly explained. OMG, these things are getting so complicated. I hope that one day a manufacturer will design and market an absolutely minimal electric vehicle. All I need is a means of transport. After all the greatest step is from taking the bus to driving a car. Any car that is. Something like the Cesnna 150 airplane.
That's a ferrite core common mode choke on the inverter, not a current sensor. It's an EMI filtering component for reducing common mode currents into/out of the inverter
Fabulous detail and presentation (as usual;)) i wonder if long tern oems will keep motor making in house as their own advantage vs. Outsourcing. Building ICE engines must be way more complex than making electric drives.
Thank you Scott. Eating this stuff up. One thought. I think we should be careful about using the term "inducing" when describing how the magnetic fields on the stator are created. Another form of the word is induction, which reminds us of an induction motor such as Tesla uses. An induction motor is an entirely different beast than this AC / permanent magnet motor out of the Rivian. All EV motors, every one of of them, every automaker, use 3-phase AC to create the magnetic field in the stator. It's all the same basic tech. The induction motor is different in that rather than than using permanent magnets in the ROTOR, they use a non-magnetized but conductive metal slug of sorts (often copper) that has an opposing magnetic field INDUCED on it from the magnetic field in the stator. This is a magnetic field inducing another magnetic field. In the stator it is an electro-magnetic field simply being created as pulses of AC current pass through the stator windings. ;>
Personally really like Scott’s presentation style. He’s very clear. Curious: Does Munro think inboard brakes make sense on these EV drive units? Seems like they could help reduce part count.
inboard brakes reduce unsprung mass, but they also increase loads on CV joints, are even difficult to package inboard than in the wheel volume, are hard to service, and bring heat into the drive unit area. In vehicles with engines they were tried and subsequently abandoned decades ago. I doubt that less frequent service moderating the service disadvantage would tip the choice in favour of inboard.
@@brianb-p6586 I’m not sure “abandoned” is the right word. They’re still fairly common in military vehicles around the world. Most of the downsides you mentioned are much less of an issue on EVs. The drive unit is smaller so packaging is easier, brake rotors are likely to last the life of the vehicle, CV joints are already being sized for more torque and regen loads, there is much less heat around the drive unit, etc
@@atomicsmith the only inboard brake wheeled military vehicle that I know of is the HMMWV, which is a 1970's design, but of course there may be many others that I just haven't come across. Were any designed in this century? Military vehicles might use inboard brakes to protect vulnerable components from threats that don't exist in the normal world. An EV drive unit is not smaller than a conventional final drive (such as at the rear of a front-engine vehicle) - in fact it is much larger. An EV drive unit also produces much more heat than a conventional final drive. The EV drive unit is only smaller and produces less heat than an engine and transaxle, so that only applies at one axle of an engine-driven vehicle. Regenerative braking is rarely capable of the torque of full effort with friction brakes.
For a long time, the tear downs on this channel could be summarized as "The engineering in Tesla's cars is mostly excellent, while the engineering in other brands of EVs is mostly mediocre". However, over time, I have noticed from the tear down videos that the quality of engineering in non-Tesla EVs seems to be improving, with this video being a good example of that. This is refreshing to see. As somebody who owns shares in Tesla, I feel confident that Tesla is still ahead. But as somebody who loves innovation and ergonomic design, I am delighted to see that some of Tesla's competitors are making impressive improvements.
11:50 sorry expert, you pointed to HV EMI filter nanocrystalline and said current sensor, but current sensor is the white one, where three phase get through.
I need to finalize my order and I’m tempted to go with Quad setup. Yes, it’s a bit heavier but I get a sense that it’s more overbuilt and will last longer. I’m not sure I like that Dual is immersed in oil. Tesla motors do that and they don’t last very long before needing a replacement due to cooling system issues. This adds a lot of complexity and possible failure points. Quad has no oil that goes inside. Seems to be less intricate but more lasting. Do you folks agree?
And this is the design after 5yrs or so after the EV revolution started. Can't wait to see the EV industry and their achievements in 10 years from now!
Will the stator oil last the lifetime of the motor or will it need to be changed every ten thousand hours or so? What SAE oil would be used? 🙂 ❤️ the channel.
The ring gear appears to have 66 teeth, the pinion that drive it might have 18 teeth (although 17 or 19 would be better), so the second reduction stage is about 3.67:1. The first reduction stage gears are finer and harder to count in the video images (although it looks like about 25 teeth on the motor's gear and about 88 on the driven gear, for about 3.5:1 in the first stage and about 13:1 overall), but it would be nice if the tooth counts or just the overall ratio were shared.
@@boredKiwiI didn't hear that in this video - maybe I missed it. Did you note the timestamp of that comment? I fed this video to a RU-vid transcript generator and the result looks reasonable... but I couldn't find any reference to gear ratio in it, by searching for key words such as "gear" and "ratio", and by skimming the text manually. Yes, 7:1 would be typical of something like a Nissan Leaf, but low for a recent design... and the gear sizes certainly look like they have much more reduction than that.
About the inverter, i see a future issue with the return line of the cooling set. If the o-ring fails, then the entire inverter as well as the battery might be a mess.
Excellent review, but I'll take the 130lbs weight penalty considering it nets 170 extra HP! Agreed that for most people, who don't need a supercar, it's cheaper and better to get the dual motor, which also has more range. I still think the original launch strategy that the engineers took of going with a quad motor, without two differentials and expensive cooling systems, achieving superior HP figures with off the shelf parts, was the right move. It will be amazing to see what HP figures they can achieve with an in-house quad motor design.
Hey Munro team, is there a reason why they had to channelise the coolant in that way to get it into the heat exchanger? Couldn't they just flip it 180 degrees? I guess in that way the casting could have been a little simpler, and maybe they could have used less rubber seal, so less surface for leaking.
Backwards compatible is pretty neat! Might they be able top product this at a low enough cost to make it arractive for other (smaller) vehicles and 3rd party OEM customers? If this system happens to get all the efficiency metrics right (I'm not sure with that oil cooling?), what type of brands would do well with this drive unit? Every 800V system that can deal with less than svelte drive units?
Yes, that's how brake-based traction control works in any vehicle, and with only one motor per axle brake-based is the only option for individual wheel control.
How's the oil pump powered? Is there much torque steer from those unequal lenght drive shafts? The open diff requiring Torque vectoring using brakes just decreases efficiency, burning money to go slower. Flawed, but Mitsubishi Evo's AYC at least used its energy to propel the vehicle forward not convert it into heat and brake dust. Is it worth using regen to torque vector? Is the invertor cooled by the same oil that serves the stator and rotor considering its sat on top of that system?
When the motor engages that differential dog, does it rev the motor to nearly match (final drive rpm of course) the wheel speed rpm so it doesn't sit there and grind? Sorry if you mentioned this in the video. I didn't catch it obviously if you did.
How much efficiency does it bring to motor when there is these permanent magnets or in case when there is no permanent magnets or is reason for using permanent magnets could be used more easily for power generation when car uses motor braking?
Might lighter vehicle with heavy BEV drive units benefit most from such disconnects? Bjorn Nyland the legendary BEV test RU-vidr does a roll out test on his range test loop. Starts a hill descent at 90 kph, switches to neutral when the car gets below 0W drive power to keep 90kph, coasts down and sees where the speed crosses below 90kph again. Wind and road conditions vary of course, aero, tires and weight all matter, but even having tested even EQS and Model S, the best coaster thus far has been Skoda Enyaq.
Scott, I am quite surprised about one aspect of this design. You stated that the rotor is living in an oil bath? As in, oil comes up to some level on the the rotor from the bottom of the case. Is that correct? That would seem to massively create resistance to the spinning of the rotor, and significantly reduce torque and power, as the rotor plows through a viscous liquid. What am I missing here??
How reliable do you think the differential will be with that disconnect feature? It looks quite complicated. Do you think that the disconnect feature is one of the reasons why the warranty on the dual-motor is one year less than the quad motor?
🤔... the benefit I see right for off roading with the induro setup is using that same disconnect feature as a locker for the front and rear independently
Needs lockers, at least in the rear, wonder if they are scared of removing the quad motor ans off road king? The independent motors limit individual wheel torque and make crawling tough, full e-locker like the lightning would solve that and make a crawling monster with the higher adjustable suspension and great approach/departure angles on the r1s!
I'm wondering why they decided to have the torque disconnect default to open instead of defaulting to closed. I suppose that they rev-match to engage it at speed, and you wouldn't want it to engage under failure and destroy itself.
Question for Scott or someone else with more knowledge than me: If you spray cooling oil on the inside of the electric motor--especially on the rotor--I would assume there would be some drag on the moving part due to the viscosity of the oil. Does that affect the efficiency of the motor or is the cooling efficiency offset that drag? I'm assuming it does but I don't know much about the type of oil being used for cooling. Followup question: since there is an oil being used in this system, is this something that will need to be periodically drained and replaced? I ask because I can just see some garages having a laugh when a Rivian owner comes in for an "oil change."
regarding the question of replacing oil: probably yes at some point, but far less frequent than on an ICE vehicle, because ev motors have almost completely smooth power delivery, so less grinding of components on each other, and also in fewer places. possible it might not even be needed in the lifetme of the car. regarding efficiency: effect is neglible in the worst case, since that kind of oil is designed to be slippy and reduce friction too. also plenty of space between moving and non moving part. (the tube that sprayed the oil in the rotor had about 1cm spacing to the rotor shaft all around)
@@unitrader403 Yes, the oil will increase drag, but my guess is that it's not a serious concern. The worst place for the oil, as far as drag is concerned, would presumably be in the narrow gap between the stator and the rotor - it isn't intentionally placed there but some oil will reach it.
In any EV drive unit oil replacement is relatively infrequent. Although there will be gear wear and resulting oil contamination, there are no friction elements (clutches) to wear, no combustion products (such as in an engine), low peak temperatures, and with no hypoid gears there is no need for extreme pressure additives. It's an easier application for gear oil than an engine, a multi-speed transmission of any type, or a typical hypoid-geared final drive; unlike typical axles and final drives, it has a circulating pump and filter to remove wear particles.
I notice that the drivers that engage the carrier pinions have a big flat spot on the outside like a toyota differential. Under high torque loads i wonder if it creates a usable limited slip effect like toyotas get. I'm just scheming how to make them better as it looks like working another spline in there for a dif lock is going to be a chore.
