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Why Carmakers Can’t Transition to Newer Chips

jalopnik.com

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Re: Why Carmakers Can’t Transition to Newer Chips

#271

Post by perl4ever »

smolder wrote: post #245
formerly_proven wrote: post #233

Earlier quoted context omitted.

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.

It's a matter of semantics, but I object to saying a braking system isn't purely brake by wire when electronics alone can cause it to totally fail.

There's a difference between a fail-safe that usually works, and a mechanical connection that's always there.

Electronics can fail in many interesting ways other than simply turning off. And they do! Ever looked at nhtsa.gov?

"Brakes Failed problem of the 2017 Honda Accord Hybrid

Failure Date: 10/31/2018

There have been three instances of total brake failure. Initial instance occured on vehicle startup, a number of errors were given including "aadaptive cruise conrtol problem","collission mitigation system problem","road departure mitigation system problem" and "brake system problem". When I put the car in drive it immediately began moving forward. Car was towed to dealer where Honda blamed the issue on the undercaoting causing components to overheat. This was October 2018 in philadelphia. Replaced brake system and removed undercoat on affected areas. Second instance occured in February 2019 it had stopped raining but road was still wet and had puddles. Driving downtown, at a yellow light brakes completely failed, I ran the light and was able to stop with emergency brake. Car was giving the same set of errors. This time restarting the car made errors go away. Brought to the dealer, they said they did a software update but could not replicate the problem so did nothing else. Third instance was February 2nd, while driving about 30-40 mph, again either after rain had stopped or still had a slight drizzle. This time I saw the errors while driving before I needed to break and recognized the issue. Managed to use emergency brake to pull over. Again restarting the car cleared the issue, I have not brought back to the dealer yet."

Re: Why Carmakers Can’t Transition to Newer Chips

#272

Post by rasz »

seanmcdirmid wrote: post #265
theHIDninja wrote: post #263

But cars don't even need chips. Cars worked just fine for 70 years without chips. I don't get it.

Blame the EPA, California for more aggressive pollution and economy standards. You could still build a 1970s car today without chips, you just couldn’t sell it.

What do you mean blame? You dont want clean air? You want rolling coal diesels? and 7 liter 25l/100km family wagons?

Re: Why Carmakers Can’t Transition to Newer Chips

#273

Post by m4rtink »

seanmcdirmid wrote: post #266
rwj wrote: post #264

Earlier quoted context omitted.

SpaceX is definitely pushing the use of off the shelf components, and good on them, but things will probably be different when they are building rockets that they expect to keep in service for ten years.

Aren’t most rockets, outside of SpaceX’s ones that can land after launching, single use? Then keeping the same rocket going for 10 years would be a problem unique to spaceX unless we count the space shuttle?

IIRC Space Shuttle also had multiple voting flight computers as well. :)

https://history.nasa.gov/computers/Ch4-4.html

Re: Why Carmakers Can’t Transition to Newer Chips

#274

Post by seanmcdirmid »

rasz wrote: post #272
seanmcdirmid wrote: post #265

Earlier quoted context omitted.

Blame the EPA, California for more aggressive pollution and economy standards. You could still build a 1970s car today without chips, you just couldn’t sell it.

What do you mean blame? You dont want clean air? You want rolling coal diesels? and 7 liter 25l/100km family wagons?

Blame doesn’t always have a negative connotation. Obviously, the chips have worked well for us.

Re: Why Carmakers Can’t Transition to Newer Chips

#275

Post by dale_glass »

coryrc wrote: post #132
dale_glass wrote: post #123

Earlier quoted context omitted.

Then I welcome the opportunity to learn about something new. Please explain what's wrong, I'm most interested.

Start reading IEEE, SAE, or other trade magazines; get an EE degree in the Midwest; get a job in the automobile supplier industry; go to industry conferences or just read their proceedings...

Or you could do me a favor and explain, since you already seem to know.

Re: Why Carmakers Can’t Transition to Newer Chips

#276

Post by perl4ever »

tuatoru wrote: post #229
perl4ever wrote: post #216

Earlier quoted context omitted.

>All of those switches become much more expensive Wouldn't a more important question be how does the failure mode change ?

Above 30V - 50V DC, contact arcing becomes a huge problem. (It's a problem below that, but less huge.) With AC, the arc will self-extinguish a half-cycle after the switch opens. With DC there is no cycle, and contacts can be completely vaporised in tens of milliseconds. Commodity switching components are usually rated "30V DC, 250V AC" for this reason. It is possible to design switches so that even DC arcs self-extin…

>To answer your question directly: no. Cost is prime

I meant to the customer or owner, over the normal lifetime of the vehicle, not to corporate accountants that translate pennies into millions of dollars.

"More expensive" presumably is a small amount per car; the average new car in the US is over $40K.

Re: Why Carmakers Can’t Transition to Newer Chips

#277

Post by tantony »

seabrookmx wrote: post #234
tantony wrote: post #179

Earlier quoted context omitted.

> Charging efficiency isn't 100%, so you'd have to tow it further than the range you need That's not how it works. You basically get 5 mpg or less on the truck, while the car charges at significantly higher rates than the speed of the truck (in mph), because the car is more efficient at using the energy. https://insideevs.com/news/514727/tesla-towing-70mph-fast-ch... Towing at 70mph in the above example was charging…

The comment you replied to is still correct though. Distance wise, tow charging makes no sense. Energy wise, maybe it does.

If it makes sense energy wise, it makes sense distance wise too. If the EV can go 4 miles for every one mile towed, then why would it not make sense?

Re: Why Carmakers Can’t Transition to Newer Chips

#278

Post by Zak »

swiley wrote: post #167
gedy wrote: post #98

Earlier quoted context omitted.

People panic and jam the wrong (or both) pedals. (There are quite a few people who use two feet to drive automatics, one foot for break, other for gas..)

I thought you would fail most driving tests doing that.

Perhaps, but left-foot braking is a useful technique, and common practice in some forms of racing.

In street driving, the main application is being ready to brake while driving normally. It is much faster to brake with the left foot hovering over the brake pedal than by moving the right foot from the throttle to the brake. Of course covering the brake pedal with the right foot precludes driving normally on a flat road or uphill.

This should of course be practiced in low-risk situations before being attempted in high-risk situations.

Re: Why Carmakers Can’t Transition to Newer Chips

#279

Post by oehtXRwMkIs »

marsokod wrote: post #259
oehtXRwMkIs wrote: post #253

Earlier quoted context omitted.

What amperage are we talking about here? Discussions of electrical safety solely in terms of voltage is nonsense.

Amperage is set by the resistance of the human body. That's in the order of 2kOhm, so at 50V, you get a current of 25mA. That's in the zone where it becomes quite intense for you. At 12V, we are just talking about 6mA, where you can feel the electricity but it should not be hurting too much.

Thanks, that makes sense.

Re: Why Carmakers Can’t Transition to Newer Chips

#280

Post by rapjr9 »

LennyWhiteJr wrote: post #21
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...

To elaborate on this, the feature sets on these low level microcontrollers are no standardized. There is no common API for them to implement. Even chips coming from the same manufacturer will have different hardware capabilities, and although low-level drivers can abstract that way to a certain extent, there will always be differences. The biggest challenge is when you need to update your firmware to use a microcontr…

I see this as a failing of microprocessor design. I/O should be standardized and there should be high level API's that do not change across chips or companies. MCU's are intentionally fragile in this respect to try to lock buyers into one MCU product family. It is absolutely stupid that I/O ports work differently for different MCU's and don't use a common API. It means every designer always has to reinvent the wheel when moving to a new MCU. This must have had a huge negative effect on product reliability and innovation. It's also why many products have moved to using Arduino's.

There is also a huge lack of improvement in MCU designs. Why doesn't my SPI bus autonegotiate everything? Why can't the serial port do the same? This should all be available in hardware as a standard feature of the ports. What a waste of decades of engineering talent to have to repeatedly troubleshoot everything at the bit level.

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