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Why Carmakers Can’t Transition to Newer Chips

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Re: Why Carmakers Can’t Transition to Newer Chips

#211

Post by brianwawok »

syntaxing wrote: post #120
mwint wrote: post #110

Earlier quoted context omitted.

Fundamentally, what is it that prevents the established auto makers from making changes mid lifecycle? Seems like Tesla keeps pulling it off; why can’t GM? Is it that the component specification+acquisition cycle you describe is optimized to take as long as the development cycle of a new car?

Disclaimer: I work and worked for subsidiaries of big automakers but this opinion is of my own. I would guess it’s a mixture of culture, cost, and scale. Culture wise, Tesla is extremely vertically integrated so that gives them a lot more breathing room. Cost wise, Tesla pretty much still sells car at a loss and relies heavily on carbon offset subsidies for income. When your revenue is established, trying to change m…

You need to read their financials closer. They are profitable without offsets.

Re: Why Carmakers Can’t Transition to Newer Chips

#212

Post by Ekaros »

useful wrote: post #118
Ekaros wrote: post #96

Earlier quoted context omitted.

That sounds like possible death trap. Drive Tesla to some place without range, stay out there for week. Then come back an notice car is dead and you can't reach next charging station. Maybe this is why Musk is making Starlink...

you can tow charge an electric car with another car or truck

How do you order an other car or a truck if you can't make phone calls?

Re: Why Carmakers Can’t Transition to Newer Chips

#213

Post by coryrc »

hulitu wrote: post #157
coryrc wrote: post #105

Earlier quoted context omitted.

I think you underestimate how poorly software development is done in traditional industries. Practice makes perfect and they mostly practice writing reports not software.

It depends. If you want to sleep well at night you take care. Of course if you are VW you take risks.

Taking a long time doesn't mean you've done more useful work.

Re: Why Carmakers Can’t Transition to Newer Chips

#214

Post by mcguire »

formerly_proven wrote: post #175
snthd wrote: post #133

Earlier quoted context omitted.

>40-60V system What makes that voltage a better trade off?

Siblings covered why 12 V is annoying, let's talk about why 12 V was chosen in the first place. 6 and 12 V electric systems in vehicles came about because lead-acid batteries made sense in this application, and cetpar. a higher voltage lead-acid battery is overall costlier to manufacture, because it contains more individual cells. Another big thing is that there are many switches and relays in a car, and those often…

I seem to recall, several years ago (when stopping the engine at traffic lights and restarting as soon as the driver released the brake), at least one company was exploring moving to 24V. However, the effort failed precisely because the lifetime of 24V switches was significantly shorter.

Naturally, I can't find any links to the info...

Re: Why Carmakers Can’t Transition to Newer Chips

#215

Post by perl4ever »

csours wrote: post #199
sandGorgon wrote: post #176

Earlier quoted context omitted.

> If you were going to design a new car electrical architecture from scratch today, you would have something like a 40-60V system with a centralized controller (or pair of controllers in a safety redundant configuration). Actually this point is something im curious about - it seems to be redundant to have a 3X redundant processor ..probably placed in different places on the car body for safety. Would that not be supe…

Do not take any of this as a particular endorsement of a safety system. Airplanes need 3x redundancy on safety critical components, because they carry a lot of people and are not fail safe when they are in the air. Cars can generally stop safely. As far as changing architectures - think about safety critical loops and real time computing. Some processes should never be pre-empted.

>Cars can generally stop safely.

"Brake-by-wire is used in all common hybrid and electric vehicles produced since 1998 including all Toyota, Ford, and General Motors Electric and hybrid models."

"Three main types of redundancy usually exist in a brake-by-wire system:

   Redundant sensors in safety critical components such as the brake pedal.
   Redundant copies of some signals that are of particular safety importance such as displacement and force measurements of the brake pedal copied by multiple processors in the pedal interface unit.
   Redundant hardware to perform important processing tasks such as multiple processors for the ECU"
"The highest potential risk for brake system failure has proven to be the Brake Control System software. Recurring failures have occurred in over 200 cases documented in NTSB documents. Because each manufacturer guards the confidentiality of their system design and software, there is no independent validation of the systems.

As of 2016 the NTSB has not directly investigated passenger car and light truck brake-by-wire vehicle accidents, and the manufacturers have taken the position that their vehicles are completely safe, and that all reported accidents are the result of "driver error"."

https://en.wikipedia.org/wiki/Brake-by-wire

Re: Why Carmakers Can’t Transition to Newer Chips

#216

Post by perl4ever »

formerly_proven wrote: post #175
snthd wrote: post #133

Earlier quoted context omitted.

>40-60V system What makes that voltage a better trade off?

Siblings covered why 12 V is annoying, let's talk about why 12 V was chosen in the first place. 6 and 12 V electric systems in vehicles came about because lead-acid batteries made sense in this application, and cetpar. a higher voltage lead-acid battery is overall costlier to manufacture, because it contains more individual cells. Another big thing is that there are many switches and relays in a car, and those often…

>All of those switches become much more expensive

Wouldn't a more important question be how does the failure mode change?

Re: Why Carmakers Can’t Transition to Newer Chips

#217

Post by a9h74j »

zh3 wrote: post #152
snthd wrote: post #133

Earlier quoted context omitted.

>40-60V system What makes that voltage a better trade off?

Power is volts x amps. The more amps, the thicker the wires need to be (volts are irrelvant). So to minise weight/wire size, use the highest voltage possible (and thus the lowest current). Losses are purely related to current (I^2*R) so the incentive is to squeezee the current (so needing to increases the voltage). There's a reason the high-voltage overheads are 432 kilovolts (or more); 10 amps at 432kV = 4.3MW (Mega…

Recent TIL:

Wire guage follows a 10log10 of ohms per 1000ft, relative to 0.1 ohms per 1000ft:

0ga .. 0.1 ohms per 1000 ft

10ga .. 1.0 ohms per 1000 ft

20ga .. 10 ohms per 1000 ft

30ga .. 100 ohms per 1000 ft

http://www.interfacebus.com/AWG-table-of-different-wire-gaug...

Re: Why Carmakers Can’t Transition to Newer Chips

#218

Post by hinkley »

csours wrote: post #51

Disclaimer up front: I work for GM. I don't work on chips or components for my day job. What follows is solely my own opinion. Some things to emphasize: OEMs (GM, Ford, Toyota, VW, etc) do not design components, and they do not want to. They design specifications for components, and then get suppliers to bid. This is great for efficiency in established ecosystems, not great for agility. To my knowledge, GM did not ca…

The suppliers are running in pretty thin margins aren’t they? Did they really have any choice but to cancel those orders or potentially go bankrupt?

If you sit on someone’s shoulders and forget that they’re doing most of the work, you can be shocked all you want when they collapse out from under you but nobody on the ground is going to have any sympathy at all for you.

I’ve worked for software subcontractors and it’s always frustrating when the customer is so excited about all the things we’re going to accomplish together, all the plans that hinge on our mutual success, and isn’t it so wonderful that they’re getting such a great deal on it too?

Meanwhile we’re slowly going broke because we can’t make money on that sweetheart deal loaded with scope creep not spelled out properly in the contracts. Good luck with those plans when we go under.

Re: Why Carmakers Can’t Transition to Newer Chips

#220

Post by formerly_proven »

perl4ever wrote: post #215
csours wrote: post #199

Earlier quoted context omitted.

Do not take any of this as a particular endorsement of a safety system. Airplanes need 3x redundancy on safety critical components, because they carry a lot of people and are not fail safe when they are in the air. Cars can generally stop safely. As far as changing architectures - think about safety critical loops and real time computing. Some processes should never be pre-empted.

>Cars can generally stop safely. "Brake-by-wire is used in all common hybrid and electric vehicles produced since 1998 including all Toyota, Ford, and General Motors Electric and hybrid models." "Three main types of redundancy usually exist in a brake-by-wire system: Redundant sensors in safety critical components such as the brake pedal. Redundant copies of some signals that are of particular safety importance such…

Generally speaking those are not purely brake by wire. The master cylinder is still mechanically connected to the pedal. However, in normal conditions the brake actuation will be performed over wire.
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