There’s Some Secret Tech Lurking In The Tesla Model 3

Tesla Model 3


Specially tuned vertical frequency?

There’s a lot of innovation in the Tesla Model 3. There’s the unique permanent magnet switched reluctance (PMSR) rear motor; the integration of the controls into a single center screen. Even the vents in the car’s HVAC system are a completely new design. Now, we’ve learned more details about other parts of the vehicle that have, quietly, undergone sophisticated development. They’re mostly associated with the chassis and suspension.

These new technical details were discovered by the team at Autocar who spoke to a number of Tesla engineers. They start with the tires, which, we’re told, the automaker spent three years working with tire manufacturers to develop. Besides being filled with sound-dampening foam, the rubber in the tread is formulated to have low-rolling resistance, yet offer good grip for a heavy vehicle with a lower-than-normal center of gravity. They also need to be able to deal with the extreme conditions of spinning at 155 miles per hour. If this sounds obsessive, read on.

The suspension, front and rear, is particularly interesting. The rear suspension, with five separate linkages and a damper, offers the wheels out back “six degrees of freedom,” says Autocar.   We’re told it is similar to a double wishbone setup, but the links have a split, which allows them to offer improved control using the feedback from the tires.

The front suspension, besides doing the typical duty of allowing the front wheels to flex up and down and turn, have an element of crash safety built in. In the case of a front-end collision, “…the front two steering links are designed to break so that the front wheel rotates around the third link, pushing the car away from impact.” Likewise, the mounts for the front motor (on Dual Motor variants, natch) are designed to pivot backward into an empty space in the case of an accident.

Interesting also are the choices made for the braking system. Tesla eschewed a cheaper option and went with four-pot brake calipers, but it didn’t stop there. To keep mechanical friction to a minimum, it engineered the piston seals to “… fully retract the brake pads after braking…” Typically, brake pads are allowed to float a bit, and lightly contact the rotors which keeps them free of surface rust. To accomplish that task, the automaker developed unspecified “new anti-corrosion techniques.

Finally, Autocar wraps up its look at the unseen innovation by informing us about the car’s vertical frequency. Now, this is something probably no one, outside of vehicle dynamics engineers, gives much thought to, but apparently Tesla used NASA data to target the frequency that would keep drivers feeling comfortable. While not saying what value it targeted —it does say autos typically range from 1.0 to 3.0 Hertz — the Model 3 is tuned to have a vertical frequency  “…equivalent of a brisk walk or a slow run,” that helps the car keep a sporty feel, but still keep occupants comfortable. Neat-o!

Source: Autocar

Categories: Tesla

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49 Comments on "There’s Some Secret Tech Lurking In The Tesla Model 3"

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No secret sauce, just a special chemical ingredient – Muskonium.

Having become used (over some decades) to thinking of U.S. brand vehicles (except trucks) being somehow inferior to foreign brand ones it is delightful to have a U.S. car company that is clearly the leader in tech and design.

Tesla is the best car company ever, when it comes to India, I will probably overstretch myself to buy it.

how funny. My wife’s family is from Chennai. She INSISTED on buying an MS. We bought a slightly used 2013 MS, and it is next to impossible to get her out of it (I personally avoid driving it much; too dificult going back to a v8 highlander which is now, slow, clumsy, etc).
However, I have to laugh that a female Indian driver in another car kind of wanted to race. I NEVER expected that. When we hit the stop light, we rolled down windows and she said that he was going to buy a tesla ASAP and sell her Mercedes.
Likewise, all the relatives that have driven this say they want to switch cars now. I guess something in the Indian blood loves that acceleration and great engineering 🙂

Lol, good to hear everyone likes the car. Doesnt seem limited to Indian buyers. 😉

like many of us here in US, who are over stretching ourselves from hondas, toyotas to Teslas..

Hyundai Accent in our case.

Some of us went from Excel, to Elantra, to Sonata.
While others of us went from Elantra, to Santa Fe, and back to Elantra. (Wife)

And I’m still p!ssed that the IONIQ BEV won’t be coming to Pennsylvania.

Article Headline: “There’s Some Secret Tech Lurking In The Tesla Model 3”

Tesla MaaS + Tesla Supercharger Network = Huge Tesla Value Add

Tesla’s biggest secret tech lurking in Model 3 is MaaS. Owning a Tesla in your home market and having access to a Tesla fleet car (via MaaS) while traveling is a powerful thing… especially the perk of all your driving preferences automatically porting over to your MaaS car.

Biggest not so secret tech can be seen in the background of the above article photo:

Access to the Tesla Supercharger Network providing convenient and reliable fast charger for those occasional long distance trips.

The Tesla Network (mobility as a service) is an interesting idea. So far, nothing more than that. It’s not even known if level 5 autonomy will ever be possible to implement using the hardware that Model 3 ships with. Tesla says it’s confident it will be, but nobody’s ever done it, so Tesla doesn’t really know either. NVidia says the board Tesla uses in Model 3 should provide level 2 to 3. And nor do we know if the sensors will suffice. Most other manufacturers are apparently convinced that LIDAR is essential to have in the mix. Tesla eschews it, because Elon. And then there is the regulatory hurdles. To have self-driving cars we need to know how to test and approve them, and figure out how to determine who’s responsible when they crash. Maybe the tech will be solved and the regulations worked out and it’ll all be doable on the Model 3 computers using the Model 3 sensors. But maybe not. By the way, Tesla is the only manufacturer that sells (accepts payment for) full autonomy today, to be delivered at some unspecified time in the future if technological progress and regulations both allow. And it’s the only… Read more »

@Terawatt said: “…It’s not even known if level 5 autonomy will ever be possible to implement using the hardware that Model 3 ships with…”

MaaS is not necessarily dependent on Level 5 Autonomy… UBER & Turo are examples of MaaS. My guess is that Tesla MaaS will launch sometime next year in limited markets and expand over next three years to all the major markets.

…Tesla MaaS my turn out to be UBER’s biggest competitor.

Never really understood why there was any real question of who is responsible in a fully autonomous crash. It’s purely based on maintenance VS software VS vehicle limitations. Under ideal conditions, an autonomous car crash would be impossible because all cars involved would be working to avoid a crash. As I see it there are only 3 ways a crash can happen: 1. Lack of maintenance. The software expected the car to be able to do X to prevent a crash, but X was not possible due to insufficient maintenance. The owner’s fault and their insurance pays*. 2. Software flaws. The software is flawed and thus did not avoid a crash it should have been able to avoid. The manufacturer is at fault and they (or their insurance) pays*. 3. Physical limitations of the vehicle. The software correctly determined what was needed to avoid the accident, but the car was physically incapable of moving in such a way as to avoid the accident. This would be a “no fault” situation for the owner/manufacturer and most likely is going to be the fault of a 3rd party (that crashed into this autonomous car) and thus they (the owner or manufacturer of… Read more »

“3. Physical limitations of the vehicle. The software correctly determined what was needed to avoid the accident, but the car was physically incapable of moving in such a way as to avoid the accident.”

There is a 4th category: The bizarre accident that nobody could possibly have foreseen, and even if they did, there would be no good reason to design the car to be able to see it coming, or program the software to react to it, because trying to include every rare scenario you can possibly imagine would cause such code bloat that it would slow down the car’s reaction time, making accidents more likely instead of less likely.

Case in point: The time a reefer tractor-trailer rig had an accident on an overpass, and frozen sides of beef spilled over the railing, hitting one or more cars traveling under the overpass. Are autonomous car designers going to design the sensors to continually watch for falling objects which might hit the car? Of course not. It’s too rare an event for it to make sense to design cars to avoid that.

I would see that as one of those “additional laws/requirements/lawsuits” with regard to defining #2 and #3 and including something like that as an exception. Specially, what is reasonable for an autonomous car to be able to detect and avoid in terms of direction, range, size, number and material. I would imagine it would be rather hard to dodge all the meat in that case. Though I should point out that it is only no fault to the car that the vehicle was hit by meat. The semi would likely be found at fault (ie: for not securing the load well enough). Another example: If something is about to crash into it at a speed of 250 mph, the vehicle likely has a 1/5 the time to react as it would at 50 mph. It software may not even be able to properly detect something approaching at that speed. Though adding a 4th section for it isn’t unreasonable. 4. Unforeseeable circumstances. Like a human driver, an autonomous vehicle cannot be expected to be able to avoid crashes in all situations. There will be situations that are so rare that the software and/or hardware were not designed to handle them. These… Read more »

Here we go again with the “permanent magnet switched reluctance” term. Tesla’s model 3 motor is not different from the majority of permanent magnet machines that have been used in the industry for some time. All interior magnet machines have a component of reluctance torque.

I thought PMSR motors all have magnets in the stator, not the rotor like most other PM traction motors. This makes the switched reluctance rotor a solid (or laminated) chunk of metal which can be much more durable than one assembled from metal and magnets and if designed correctly it heats up a lot less than an induction motor rotor, which is the achilles heel of the model S and X motors.

I have been unable to find any information on the Model 3 motor construction, however, to confirm my speculations. Do you have any sources that show the motor as an interior magnet machine with magnets in/on the rotor?

There is a deep dive into the subject in a Clean Technica article (link below). And there have been a lot of people with experience in electrical engineering who say that’s a load of hooey.

Since I’m not an electrical engineer, I won’t venture an opinion. I will note, however, that the scientific method seems to be distinctly missing here. The matter won’t be settled by who shouts the loudest, nor who states their opinion as fact the most times. The matter will be settled by someone disassembling one of the new Model 3 motors and posting photos online… or at least that will provide some actual evidence to argue over! 😉

Incorrect. It is a true switched reluctance motor. The magnets don’t perform the same task as those in a standard PM motor. They are there to smooth out the power, which was the main thing holding back SRMs in the past. This is why there is much less magnetic material in this motor than a regular PM motor.

Dude, you are clueless. It is an interior permanent magnet machine. Do you work in the industry? I do. I have seen it.

Really? What do you do then? Because experienced Electrical Engineers have confirmed this.

I work in motor design and calibration for an automaker. The model 3 motor is good, but not different than the rest of the industry. That is what I take objection to.

Not according to Sandy Munroe who has torn apart nearly all vehicles INCLUDING the EVs. In fact, he says design is based more on Halbach effect and they are STILL studying the design. The motor is much lighter than the garbage that comes from Audi, MB, GM, Nissan, etc. AND far more powerful.
So, no, it really is different.

BUT, you can continue to claim otherwise, while the rest of society knows better.

“The motor is much lighter than the garbage that comes from Audi, MB, GM, Nissan, etc. AND far more powerful.

No, it isn’t.

I am not saying there is anything wrong with it, but the idea that this machine is something unique and special to Tesla is false. All interior PM machines have a component of reluctance torque.

Here we go again with armchair engineers stating their opinion about the new Model 3 motor as fact.

I have yet to see anyone post actual photos of a disassembled Model 3 motor to settle the matter one way or another.

Yes, from the pictures it seems that Jon was right and it is not radically different from the architecture used in most other recent EV motors based on the pictures of other motor rotor cross sections in that same article. They are all a hybrid combination of permanent magnet motor and reluctance motor with different manufacturers deciding what the optimum mix of one and the other should be based on speed/power envelope.

The picture of the stator winding seems to be a conventional non-salient distributed construction. This would indicate that the motor is more of a permanent magnet synchronous reluctance machine and not a permanent magnet switched reluctance machine. Switched reluctance machines (like stepper motors) also do not usually have three phase electrical connections since their phase windings are magnetically separated from each other rather than integrated like in most other motors.

Does this mean that traction motor design is mature enough that not even Tesla has found a better solution?

I’m no expert myself, but I’ve seen experienced EE’s such as Ingineerix be quite adamant that this is an PMSRM. Here he is debating it with another EE:

It’s important to note that the other EE admits he doesn’t know all that much about these motor types, but he does suggest that there is some dispute as to the modern definition of a Switched Reluctance Motor. I’ve seen some say that motors like the one in the Bolt are a Synchronous RM, while the Model 3 is a Switched RM.

I’m no expert myself, but I’ve seen experienced EE’s such as Ingineerix be quite adamant that this is an PMSRM. Here he is debating it with another EE: reddit dot com/r/cars/comments/93277o/2018_tesla_model_3_regular_car_reviews/e3a5cpq/?context=1

It’s important to note that the other EE admits he doesn’t know all that much about these motor types, but he does suggest that there is some dispute as to the modern definition of a Switched Reluctance Motor. I’ve seen some say that motors like the one in the Bolt are a Synchronous RM, while the Model 3 is a Switched RM.

Looks like the link sent my comment into moderation. Since I don’t know if comments here ever leave moderation, I’ve copied and pasted my comment and modified the link.

Shaun, this is mostly an argument about semantics. The point I have been trying to make is that all interior pm machines have some reluctance torque. Tesla calls it something different than everyone else and the media interprets that as they invented something unique. That just isnt the case.

Google interior permanent magnet motor. It is exactly as described. Reduction in rare Earth metals, some reluctance torque.

This is no criticism of Tesla, but it is false to conclude it is unique.

“They are all a hybrid combination of permanent magnet motor and reluctance motor with different manufacturers deciding what the optimum mix of one and the other should be based on speed/power envelope.”

I’m very far from being an electrical engineer, but even I know that Tesla has in the past never used a motor with any permanent magnets in it. They have all previously been induction motors.

However, previously in your comment you used the qualifier “most other”, so perhaps you meant to exclude Tesla’s other cars from your assertion there?

That is the same as any other motor in the industry; an interior PM machine.

Armchair engineer? Nope. I work at a major OEM doing motor design. Not opinion, an observation of fact.

Jon, on this motor, how much cogging torque is there when the motor is almost stopped? Or does it have a non-star-wheel rotor?

Oh, ok, – just looked at the MUNRO breakdown pics. Seems like it has slight ‘salients’ in the rotor – I’d guess minimal cogging – not enough to feel in the passenger compartment.

Oh, another thing: don’t worry about the armchair engineer guy. If you dispute anything he says (he for once here admits he doesn’t know anything), he’ll claim he’s the big expert about electric cars even though its illegal for him to drive anything (has no driver’s license) – strange for a 64 year old. He also has no intention of ever even buying any kind of Electrified vehicle, even for a relative.

Pity poor Bill. He’s so jealous that a guy who has never owned an EV, and has no training or experience as an electrical engineer, understands their engineering so much better than he does… despite Bill claiming to be an electrical engineer! 😆

My apologies, Jon. Clearly you are not in that category, and I thank you for your input on this issue.

It’s great to see comments from someone who actually has experience working in this field. If you’re not an expert, then at least you’re likely the closest we’re ever going to an expert from anyone posting about the subject here!

…altho, as I look back over the conversation, Jon, my comment about “armchair engineers” was a response to someone else’s comment, not one of yours.

Tesla’s use of alien technology was confirmed when Musk sent his Roadster back.

I was impressed with the suspension and continue to stay impressed.
It amazes me how large companies, like GM, can put in such cheap suspensions, that they know will hurt ongoing sales, and do so anyway, with cars that price around $40,000.

Without consideration for how this hurts their brand.
Sure, if the Bolt were the only EV on the market, I’d buy it, but, is that how you successfully sell cars?
I guess, I’m disappointed with GM leadership.
Because we all know the engineers can and have done better.

That’s the thing, though. They don’t know that it will hurt sales to put in cheaper suspensions, etc. On the contrary, they’re counting on buyers not noticing or caring, which would allow them to increase profit.

Tesla, by virtue of being a newer company, and by virtue of the CEO’s prestige and social media presence, does not have the built in brand loyalty as GM has. And that means they can cut fewer corners because they know people will give their products greater scruitiny. Most of the cost-saving measures were about the interior, which gave Tesla the money to make the driving components as best they could.

Lol. GM magnetic suspension is industry-leading. The rear suspension on Volt was documented on youtube as a technically superior and cost-effective build.

Cost effective does not equal inferior.

Last time i looked that magnetic suspension was not on the Volt or Bolt

Seems to be correct regarding the Volt, at least. Googling [volt magnetic rear suspension] I get a hit at the GM-Volt forum… but it’s a comment about a Corvette, not a Volt.

I’ve seen lots of complaints about the Volt’s rear suspension, so it would surprise me if it was magnetically enhanced.

I can’t say that I know a lot about magnetic suspensions, but just because GM has one doesn’t mean they use it on every car. Certainly not the Volt and the Bolt.
Your wording implies that the Volt has a magnetic suspension even though you didn’t mean that.
Then you write the words “documented on youtube (sic)” as if that was an industry reference or some well respected source.
You might want to hone your debating skills.

> There’s the unique permanent magnet switched reluctance (PMSR) rear motor The linked piece, and even its source, an article on ChargedEVs from months before, contains zero mention of switched reluctance, much less why that’s supposed to be important. You also fail to mention that although the REAL reason Tesla used inductance motors was probably nothing deeper than that was what they had to start with, Tesla said, back when the Model S was new, that it used induction because permanent magnets require rare earths. (An electromagnetic field can of course be induced in a simple copper coil, as most curious kids have sure done themselves at some point.) For their volume model however rare earths was no longer so important..! A lot of the talk about Tesla’s technology is nothing nothing more than hype, and I often cringe at an obvious lack of even basic competence in so-called “experts”. Munroe, for example, clearly had absolutely ZERO familiarity with computer hardware and thought NVidea’s cheaper board for autonomous cars was military-grade or even NASA level tech, when in fact it is very similar to the GPU hardware found on popular graphics cards – and available off the shelf to any… Read more »

Are you saying Renault and Nissan is too technology more advanced than Tesla in BEVs? the Leaf and Fluence of Renault more advanced than Tesla mod 3? HUmmmmm

“For their volume model however rare earths was no longer so important..!”

Terawatt, you have a really bad habit of accusing others of ignorance on a subject while exposing your own. That’s on full display here.

Manufacturers of strong permanent magnets have figured out how to make them using much less rare earth elements, and thus make them considerably cheaper. I’ve also read claims that Tesla figured out how to use much smaller permanent magnets embedded in the rotor, altho from comments by Jon here, that may be an industry standard and not an innovation from Tesla.

Anyway, the point here is that Tesla didn’t suddenly change its mind about permanent magnets; it’s that the cost and usefulness of permanent magnets has changed significantly since Tesla started producing the Model S.

I’ve been a little disappointed with the wear on the tires. The Michelin Primacy MXM4 had 9/32″ when new and are now at 6/32″ rear and 7/32″ front after 4200 miles. At this rate, i’ll need new tires at 12k-15k miles. They have a 500 wear rating, so they should get at least 30k miles. BTW, they are $277 each.

Tesla’s secret sause is attention to details

About the “switched reluctance motor” there were many discussions here, Siemens is building them “Simotics” since a few years so maybe the following link can highlight some advantages of this design: