Why Carmakers Can’t Transition to Newer Chips • Hacker News Board

Re: Why Carmakers Can’t Transition to Newer Chips

#241

Post by idiotsecant » Sat, Oct 02, 2021, 9:18 PM UTC

formerly_proven wrote: post #230

idiotsecant wrote: post #190

Earlier quoted context omitted.

This isn't really a fundamental problem. It just means using relays with contacts rated for higher voltages. It's probably the easiest part of the bom on a typical vehicle to move to a higher voltage range. I use 125VDC contact/coil rated relays all the time.

It is a fundamental problem (it's physics). The current rating for relays drops off sharply as the DC voltage increases; you might see 125 V DC rating, but the current will be a fraction of the nominal current at the rated AC voltage. If you're using an relay rated for up to 250 VAC/DC, then the breaking capacity with DC might be as low as 1 % compared to AC. Bad relay datasheets don't mention this at all, or maybe o…

I am an engineer in a field that has been using >100VDC relays for a hundred years. There is a sizable supply chain out there for these things. You can buy them in whatever amperage you need, they just use different construction from typical low frequency AC relays. Wipers are often high quality metallurgy to extend life and they make use of simple passive magnetic snubbers to 'blow out' the arc that is self-extinguishing in AC circuits. They aren't substantially more expensive than regular high quality AC relays and use standard form factors.

Re: Why Carmakers Can’t Transition to Newer Chips

#242

Post by a1369209993 » Sat, Oct 02, 2021, 9:21 PM UTC

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…

> The more amps, the thicker the wires need to be (volts are irrelvant).

Nitpick: the wire as a whole includes insulation, which technically does need to be thicker at high voltage (though at 40-60V, and maybe even at 40-60kV, it's probably dominated by tolerances for erosion and abrasion and such).

High voltage power lines use air, which is actually a fairly good insulator per se, but has the problem that wires tend to pass through it on their way to a short circuit if not well-restrained.

Re: Why Carmakers Can’t Transition to Newer Chips

#243

Post by alfiedotwtf » Sat, Oct 02, 2021, 9:21 PM UTC

hinkley wrote: post #218

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…

> 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.

Ajax Fasteners where a small manufacturer in the name of Division of Labour, and when they went into receivership, it took down Australia's entire car industry. Let me repeat - Australia no longer has a car industry.

Re: Why Carmakers Can’t Transition to Newer Chips

#244

Post by ChuckMcM » Sat, Oct 02, 2021, 9:28 PM UTC

The middle road is missed here.

There are two problems, long duration supplies of a chip on the same process, and the cost of making chips.

If the semiconductor companies can figure out an ASIC/FPGA type strategy that would allow any of the current chips in a car be produced "dynamically", then the semiconductor company could achieve their economies by just fabbing one design, and car companies could achieve longevity by getting commitments for production of that one design.

Xilinx recently made some steps in a new direction by producing what they called an "RF" SoC. Where RF stands for radio frequency. Basically it had all of the analog to digitial and digital to analog bits on the chip in addition to some FPGA fabric and some ARM AARCH64 cores. Its expensive and small quantity but I think it will turn out to be important in the long run as the vanguard of chips that are not 'type specific' at the time of manufacture.

Imagine a company that has the same basic FPGA architecture, packaged in a variety of automotive spec packages, with one-time programmability. That would reduce the number of SKUs considerably (basically by package type).

Re: Why Carmakers Can’t Transition to Newer Chips

#245

Post by smolder » Sat, Oct 02, 2021, 9:37 PM UTC

formerly_proven wrote: post #233

perl4ever wrote: post #226

Earlier quoted context omitted.

This is a question of semantics, but I don't understand your usage of "purely". How can it not be "purely" brake by wire, if, when depressing the brake pedal, the friction brakes are not always triggered? If electronics decide not to apply hydraulic force when everything is going fine, that there must be a potential failure mode where they ignore the pedal inappropriately. Can you explain further?

In a brake-by-wire car, if you stomp on the brake pedal with all you've got you end up engaging a cylinder that can directly exert force on the front brakes, even if the electronics are fully dead. (Maybe there are some systems where the brake pedal is truly just a "dimmer switch", but I've not been able to find them).

Yeah, brakes that don't function when power is lost would just be too brittle. That'd be unacceptable in any market regulated by one or more working brains.

Re: Why Carmakers Can’t Transition to Newer Chips

#246

Post by ahepp » Sat, Oct 02, 2021, 9:39 PM UTC

01100011 wrote: post #29

schiffern wrote: post #7

> “We were able to substitute alternative chips, and then write the firmware in a matter of weeks,” Musk said. “It’s not just a matter of swapping out a chip; you also have to rewrite the software.” https://www.theverge.com/2021/7/26/22595060/tesla-chip-short...

As far as I can tell, Tesla plays fast and loose, treating their product like a manufacturer of consumer electronics and not a manufacturer of a dangerous and durable good. That obviously allows them to out-compete other auto manufacturers who are more aware of things like product liability. See the Toyota accelerator-gate lawsuits. From https://en.wikipedia.org/wiki/2009%E2%80%932011_Toyota_vehic... : > However, on…

Isn't the fact that Toyota lost this case damning to traditional automotive software development practices, rather than evidence of their importance?

The traditional players are already doing a bad job trying to write safety critical software the way things are now.

Re: Why Carmakers Can’t Transition to Newer Chips

#247

Post by tablespoon » Sat, Oct 02, 2021, 9:49 PM UTC

alfiedotwtf wrote: post #243

hinkley wrote: post #218

Earlier quoted context omitted.

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…

> 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. Ajax Fasteners where a small manufacturer in the name of Division of Labour, and when they went into receivership, it took down Australia's entire car industry. Let me repeat - Australia no longe…

> Ajax Fasteners where a small manufacturer in the name of Division of Labour, and when they went into receivership, it took down Australia's entire car industry. Let me repeat - Australia no longer has a car industry.

Holy crap: https://www.abc.net.au/worldtoday/content/2006/s1719988.htm

You'd think the car companies could have just bought the manufacturing assets of the supplier if it was this critical (that's assuming they weren't looking for a back door excuse to shut down their own Australian production, that is).

Re: Why Carmakers Can’t Transition to Newer Chips

#248

Post by uvesten » Sat, Oct 02, 2021, 9:52 PM UTC

I did a short stint in the automotive industry ~10 yrs ago (on the software/safety side) at one of GM’s brands. The lack of forward-thinking was absolutely horrible, as was the constant insistence that anything new would never work (you remember the constant doomsaying about tesla?). I got out as fast as I could, I seriously think that being in that environment might cause serious mental impairment… So, not in the least bit surprised about this. Just nice to hear that the world is moving on whether the big auto brands wants it to or not.

Re: Why Carmakers Can’t Transition to Newer Chips

#249

Post by HeyLaughingBoy » Sat, Oct 02, 2021, 10:09 PM UTC

R0b0t1 wrote: post #204

acranox wrote: post #197

Earlier quoted context omitted.

Another factor I haven't seen mentioned in the responses yet is safety to human bodies. You (or your kid) can stick a wet finger in a 12V DC charger socket in your car and not get an electric shock, including any of the exposed contacts under the hood, including the battery terminals. But once you're up to 40-60V, the risk of electric shock to humans is actually something that needs to be factored in.

You'll get a shock if wet slightly below 9V. It just stays on your skin. Voltage penetrates dry skin at around 50V, and this is the legal definition of high voltage.

Something I learned around 12 years old, licking the terminals of a 9V battery :-)

Re: Why Carmakers Can’t Transition to Newer Chips

#250

Post by baybal2 » Sat, Oct 02, 2021, 10:12 PM UTC

kevin_thibedeau wrote: post #66

baybal2 wrote: post #55

Earlier quoted context omitted.

Most drive by wire systems I seen are nothing, but a simplest closed loop PIDs. It's very close to what you are taught in the "How to write a PID controller" class without much extra creativity.

Deciding how much fuel will be injected each cycle is not just a simple PID. The throttle body control may just be a basic servo (although it probably isn't) but the system controlling it is more complicated.

A separate circuit to map fuel/gas ratio for a given sensor input is also not a rocket science.