All engineering topics (out of main)

[Artful Dodger]

The drivetrain would I think be at most an iteration of the last one built for M3 and Y. Sure, that underlying advanced design will be resized for Model 2 but that is a more manageable engineering task than making a fully new design that is improved in a number of ways.

Tesla does its motor designs at its R&D facility located at the University of Athens, Greece engineering department. They have not put out a significant new design since the SRPM motor for the Model 3, which was first demonstrated publicly back in March 2016. So that's over 4 yrs ago now since the engineering work was done for that. I'd be shocked if in the intervening 4 yrs they have not already designed a new generation of follow-on products more suited to a small world car.

I'm also looking for blue-sky, blank-sheet of paper designs from this engineering group. Oh like maybe, wheel motors that replace the entire wheel, tyre, and brake disc. Or hubless designs which include suspension. Or... hey, this is NOT Sparta! It's Athens!

The new design must be cheaper to produce, be robotic assembly friendly, more efficient, and also exude Elon's philosophy: "The best part is no part". What can we get rid of? If we have regen braking, why have friction brakes (cost, mass, unsprung weight, angular momentum). How do we get replace a separate suspension for a City car that doesn't need to go off-road?

So lots of challenges for the mechanical engineers at the Tesla China design center, but I believe the motor design will come from Greece. Oh, and Art from China.

Cheers!

 

[Fredneck]

I'm also looking for blue-sky, blank-sheet of paper designs from this engineering group. Oh like maybe, wheel motors that replace the entire wheel, tyre, and brake disc. Or hubless designs which include suspension. Or... hey, this is NOT Sparta! It's Athens!

Blue sky work is great, but the problem with hub motors is weight. There's no good way to get the weight out of an electric motor and weight in the wheel is a bad thing, a very bad thing. Much better to keep it in the car body.

The new desing must be cheaper to produce, be robotic assembly friendly, more efficient, and also exude Elon's philosophy: "The best part is no part". What can we get rid of? If we have regen braking, why have friction brakes (cost, mass, unsprung weight, angular momentum). How do we get replace a separate suspension for a City car that doesn't need to go off-road?

The big problem with getting rid of friction brakes is reliability and safety. The electric motors are not reliable enough to count on working every minute of every day for the life of the car. We've done a lot of work to make hydraulic brakes safe. It would be very, very difficult to make electric brakes that reliable.

So lots of challenges for the mechanical engineers at the Tesla China design center, but I believe the motor design will come from Greece. Oh, and Art from China.

Cheers!

As Musk discovered a few years ago, building cars in large quantities is as much about the machine building the machines as it is the machines being built. So they need to continue to improve the manufacturing process and lower the cost of the machines they build if they really want EVs to be truly mainstream. If they can produce a 200 mile range 4 passenger EV to sell at a profit for $20,000, they will own the world. It's more about cost than it is performance.

 

[Artful Dodger]

There's no good way to get the weight out of an electric motor

Lol, Elon Musk Buff Mage tweeted engineering is "the closest thing to magic that exists in the real world".

The car doesn't need a wheel rim if the stator replaces its function. Electro magnetic suspension in what use to be the tyre. There's thousands of dollars of cost savings here in materials, assembly, and maintenance.

I'm talking REAL blue-sky *sugar* here, not the timid milquetoast approach preferred by fragmented organizations who's vision is limited by quarterly results.

So what's the next major component for Tesla to take vertical? It's the pneumatic tire. There's a thousand+ dollars of costs to examine for every car produced. What's next?

Spoiler: The $64K Question:

Will it work on Mars?

Cheers!

 

[Rashomon]

Blue sky work is great, but the problem with hub motors is weight. There's no good way to get the weight out of an electric motor and weight in the wheel is a bad thing, a very bad thing. Much better to keep it in the car body.

I beg to disagree. While Tesla's PMAC motors for the 3 are the best automotive motors available, they're a long way from what is possible. Some of the best motor design work in the world is being done in the US, and the torque and power density achieved make hub motors very interesting.

 

[Tyler34]

The big problem with getting rid of friction brakes is reliability and safety. The electric motors are not reliable enough to count on working every minute of every day for the life of the car. We've done a lot of work to make hydraulic brakes safe. It would be very, very difficult to make electric brakes that reliable.

While I agree that getting rid of friction brakes altogether might not be safe yet, could we get rid of rear brakes? Would improve efficiency a lot by removing about 30 lbs of roatating mass and another 20 lbs of unsprung.

 

[Fredneck]

There is talk of 48v motor generator "mild hybrid" systems now. I guess every idea comes around full circle. Ain't gonna happen since it is lipstick on the pig that is an ICE engine. 48v systems for general electrical needs just don't make sense. The difference in wiring needed is minimal in an electric car where you don't even need the high amperage starter motor. Even in an ICE car the differences would be pretty minor.

You microcontroller idea has some merit, but the fact is that running a minimal 3 wire harness isn't much more of a savings labor wise or cost wise than say 12 wires and no mcu. Reliability might be better without X number of mcus and just having a traditional wiring harness (flat or otherwise) with a central "brain". Like I say it is interesting but I think if you sat down and mapped it out it wouldn't necessarily work out. I don't think Teslas have that number of mcus that traditional ICE cars do.

My prior post was deleted, so I'll try to be more on topic. As Tesla builds cars in ever larger quantities, they will need to be penny obsessed like all the other car makers. The issue of installation of complex harnesses is not a trivial one. That was one of the areas that was addressed by using expensive humans rather than machines. Smaller, simpler harnesses can allow more robotic assembly at less cost. Look at this harness and you will see better what I mean.

VW Jetta right hand front door harness

This doesn't include all the wiring needed to get the wires to the door.

MCUs are very inexpensive, costing less than the connectors. Wires add significant weight costing range. MCUs are more reliable than the connectors. The vast majority of failures in electronics are in electromechanicals (switches and connectors). So a more reliable car would trade off connections for electronics.

That's the way to secure profitability, lowering manufacturing costs. Without profitability the EV revolution will be short indeed and Tesla stock will drop to zero.

 

[Fredneck]

While I agree that getting rid of friction brakes altogether might not be safe yet, could we get rid of rear brakes? Would improve efficiency a lot by removing about 30 lbs of roatating mass and another 20 lbs of unsprung.

You'd have to ask someone else what the standards are. My T100 had 255,000 miles without ever replacing the brake shoes. So clearly the rear brakes weren't doing much. Maybe that is realistic. It would likely save some bucks off the costs and help with profits. I'm mainly worried with keeping up profits. Without that the stock price tanks and I can't buy my house in Florida next year.

 

[jerry33]

While I agree that getting rid of friction brakes altogether might not be safe yet, could we get rid of rear brakes? Would improve efficiency a lot by removing about 30 lbs of roatating mass and another 20 lbs of unsprung.

The rotating mass of the brakes is close to the centre of rotation, so you don't get a very big bang for your buck. The unsprung weight is a good point.

 

[Fredneck]

I beg to disagree. While Tesla's PMAC motors for the 3 are the best automotive motors available, they're a long way from what is possible. Some of the best motor design work in the world is being done in the US, and the torque and power density achieved make hub motors very interesting.

It's not about torque or power density. It's about weight. Adding weight to the wheel is bad in multiple ways. That's why they even have a fundamental metric for the limitation in smooth rides called "sprung to unsprung weight ratio". Another issue is that there is a 9 to 1 gear ratio between the motor and the wheel. Change that to 1 to 1 and you get a very different performance from the motor.

We can argue about this all day, but what is the big advantage of putting the motors in the wheels???

 

[Nocturnal]

Someone totaled her car, and nothing else was available. (Today you would modify that to say nothing else was available unless you wanted to play chauffeur for a couple of months.)

I mean today, assuming you could buy a 3.

While I agree that getting rid of friction brakes altogether might not be safe yet, could we get rid of rear brakes? Would improve efficiency a lot by removing about 30 lbs of roatating mass and another 20 lbs of unsprung.

For a down market model that doesn't have tons of power that might be reasonable. Regen on the rear wheels and friction on the front. ​

 

[jbcarioca]

Tesla does its motor designs at its R&D facility located at the University of Athens, Greece engineering department. ..., but I believe the motor design will come from Greece. Oh, and Art from China.

Cheers!

BTW, you know they also designed the motors for the I-Pace when Jaguar accidentally found they'd hired a Greek electrical engneer.

I'm suspecting very few people know about this. In fact they are not from the University of Athens though. They are based at the Demokritos National Center for Scientific Research where teh three top engineers came from the
National Technical University of Athens. These facilities are pretty widely renowned within their field, unheard of outside.

Here are the links:
Tesla taps into electric motor engineering talent in Athens - Association Meetings International
National Centre For Scientific Research Demokritos – Official Web Site
NATIONAL TECHNICAL UNIVERSITY OF ATHENS

Any of us who are even vaguely interested in electric motor technology and related fields should look into these people. They are really inspiring.

Most of us probably know that Dalhousie University Clean technologies Research Institute is dominant in li-ion batteries:
https://www.dal.ca/dept/ctri.html

What these tell su is that Tesla does not 'go it alone'. Tesla finds the best in the world at any given subject, then establishes whatever approach they need to learn from them.

From factory automation to design that is the Tesla practice. Bluntly, they are so very smart they actually do not think they know it all. It's a bit surprising that so few of us focus on continuous reinvention from the best sources they can find is how Tesla stays decades ahead.

I fully expect this will happen [as it already is] in China. The Model S design was helped immeasurably by German technology, but Tesla has already been adopting German factory automation and will shortly add much much more.

All this multi-national, multi-cultural talent infusion will continue to drive innovation faster and faster. This stuff is 'secret sauce'. True muti-disciplinary collaboration is excruciating and infuriating (I've do it). The results are magical even though nearly everyone refuses to do it. That is why some top managers at Tesla would never leave, That is why others burn out quickly.

Elon is so immensely talented at this that people ascribe his own talent as the driving force. I do not wish to detract from that in any way, but I actually think that seeing the best talent wherever it is and acquiring that talent however he can is what makes it all work.

That is simply not replicable even by people who believe it to be true. Cultural bias is almost always too strong. Not so for Elon.

 

[Tyler34]

The rotating mass of the brakes is close to the centre of rotation, so you don't get a very big bang for your buck. The unsprung weight is a good point.

I believe there is an aftermarket rotor vendor who claims 15miles additional range for a model S by using their 12lb rotors instead of the stock 17lb ones. Can't find their link now though.

 

[jerry33]

I believe there is an aftermarket rotor vendor who claims 15miles additional range for a model S by using their 12lb rotors instead of the stock 17lb ones. Can't find their link now though.

I'd be very leery of that claim. There have been a number of lighter wheel evaluations that showed little or no improvement--some had much more than five pounds difference. (The main rotational force in a tire/wheel assembly is from the belts and tread compound.

 

[Tyler34]

I'd be very leery of that claim. There have been a number of lighter wheel evaluations that showed little or no improvement--some had much more than five pounds difference. (The main rotational force in a tire/wheel assembly is from the belts and tread compound.

Any links to these evaluations? Tesla also distinguished ranges between the 18" and 20" wheel m3 variants recently and that rotational mass certainly showed a difference.

 

[jerry33]

Any links to these evaluations? Tesla also distinguished ranges between the 18" and 20" wheel m3 variants recently and that rotational mass certainly showed a difference.

They are in TMC somewhere. I'd suggest that the tires are making the difference.

 

[Artful Dodger]

You can picture anything you want. Actually ways to make things work is a bit tougher. Tesla can blue sky all day long, but there needs to be results that help with the products and the profit.

... said every single smart engineer/business person in 2008 2012 2015 2017 2020.

/S

 

[FreqFlyer]

As far as S/X revisions, the fact that Plaid S third row has been stated as supporting larger passengers suggests to me that there are rather significant body changes.

Here's the lower portion of a Model S unibody with all of the components necessary to make it a rolling chassis, and a battery:

To get more space for third row passengers would likely involve significant changes to that rear section. (The well in the Model S floor where the seats are stowed, and where third row passengers' feet go, is behind that structure.)

Now, given Tesla's focus on economies of scale, the question is whether that would only happen for the Plaid cars, or for everything. (And, could it even happen for everything? After all, there must be motor packaging changes enabling that...)

1. Is the Plaid battery upgrade attached to the same 7 year old chassis in the above pic or a new one (maybe based on the 3 platform)?

2. Is the body attached to said chassis the same or a new one?

The answers will be revealed soon.

 

[TheTalkingMule]

Doesn't it seem kind of silly to let all these posts clog up the main thread, then just dump them here in the trash?

Certainly it would have been better to make this conversation happen in the appropriate forum as part of a robust and ongoing discussion that everyone can participate in?

 

[Prunesquallor]

That's a misnomer. A (lift neutral) object entering the atmosphere always curves inward toward the planet from aerodynamic drag. What people refer (erroneously) to as "skipping" is when it has enough velocity to escape on a pass, despite aerodynamic drag. There's no "bouncing off" effect from the atmosphere, no upwards-pointing force vector.

That said, it's possible, in a spaceplane, to dive to accumulate speed, then pull up and bounce back out, then repeat the steps a number of times, and thus "skip" directly across the atmosphere much like a stone across a lake. Armstrong did this in the X-15. But that's a special case and requires active aerodynamic control.

Shorts think TSLA is like an incoming meteor. It's actually like a rocket. It's just staging at the moment.

You can also change the orbit plane if your entry vehicle has a little lift and enough velocity. I wrote a Master’s Thesis on that very topic back when dinosaurs ruled the earth.

 

[Curt Renz]

Mobileye is no longer a Tesla supplier, nevertheless their general outlook and time-frame projection for autonomous driving may be interesting.

CNBC - hour ago: