[HN Gopher] The motor turns too much
___________________________________________________________________
The motor turns too much
Author : mooreds
Score : 365 points
Date : 2024-10-28 12:29 UTC (6 days ago)
(HTM) web link (www.projectgus.com)
(TXT) w3m dump (www.projectgus.com)
| Animats wrote:
| This shows why BYD developed their "e-axle" system.[1] The drive
| axle, differential, and motor are an integrated unit. There's an
| electronics box that connects the battery, the e-axle, and the
| charging port. It's controlled over CANbus. So there's a coherent
| standalone component BYD can reuse in many different vehicles.
| Which they are doing, and clobbering Detroit on price.
|
| [1] https://www.yolegroup.com/technology-outlook/whats-in-the-
| bo...
| weaksauce wrote:
| how repairable is such a design?
| dghlsakjg wrote:
| It isn't inherently more difficult to make it more or less
| repairable.
|
| Repair ability is a design attribute that is planned for.
| magicalhippo wrote:
| I guess a repair could mean swap it out, and the unit would
| get sent back to get refurbished, like what's commonly done
| with say alternators.
| Animats wrote:
| There's an e-axle repair kit from Germany.[1] This kit is for
| a Schaeffler e-axle, and contains all the bearings and seals.
| If you have to take the axle apart to replace any of those,
| you may as well replace all of them.
|
| Third party E-axles are mostly for trucks, where power trains
| and truck bodies come from different manufacturers. Heavy
| trucks can be maintained for decades, and that market wants
| repair parts available. For a car, the powertrain bearings
| tend to outlast the useful life of most cars.
|
| [1] https://www.repxpert.com/en/eaxle
| wakawaka28 wrote:
| >Which they are doing, and clobbering Detroit on price.
|
| Let's be real, their prices are lower because Chinese labor is
| cheaper. US companies have to pay US rates and import as much
| as they can rather than having it all made in the US.
| bryanlarsen wrote:
| Labor is under 10% of the cost of an electric car.
| 0l wrote:
| Is there a source on this? And is this the labor cost for
| the final product, or also that of all components?
| bryanlarsen wrote:
| The UAW puts it at 5-8%. Other sources put it higher, up
| to about 15%. But that's for combustion vehicles -- most
| sources put the labor component of EV's at 40-60% of that
| of combustion vehicles.
|
| It generally includes the labor for sub-assemblies, but
| not for components. Components are sourced globally, so
| manufacturers in different countries should not be paying
| substantially different prices for components. Certainly
| sometimes they do, but that's generally a tariff issue,
| not a labor issue.
|
| Not an expert, this is just based on most of an hour of
| random Googling.
| criddell wrote:
| Does labor include healthcare and pension costs?
|
| A high school teacher once told me that the most
| expensive part of a car is healthcare and pension costs.
| Road and Track reported on this a little while ago, no
| idea what the situation is today.
|
| https://www.roadandtrack.com/car-culture/a9590/pension-
| costs...
| wakawaka28 wrote:
| Although this may be true (I haven't found much to the
| contrary in a few minutes of searching", "raw materials"
| also involve labor. Facilities in the US are bound to cost
| more as well because property is so much more expensive. US
| auto workers and engineers make easily 10x as much as
| Chinese counterparts.
| thescriptkiddie wrote:
| labor is 100% of the cost of everything. not 100% of the
| price, as that includes things like profit margins and
| taxes, but 100% of the cost.
| Cthulhu_ wrote:
| I'm sure that's a factor, but probably not for long - Chinese
| wages are on the rise along with China's economy, still a
| long way from US wages but they doubled in the past decade
| according to [0].
|
| But one thing that's hard to deny is that US and European car
| manufacturers are still building on top of previous
| iterations of their vehicles, swapping out a ICE with an
| electric system but keeping the existing systems,
| frankensteining the two together. The article itself makes
| note of it:
|
| > More than five separate CAN buses, ten or more kilograms of
| low voltage wiring, probably over one hundred electronic
| modules (most with their own CPU and firmware), etc.
|
| I don't know cars, granted, nor legislation, but surely a car
| engineered from scratch would be much simpler and thus
| cheaper to build? How does Tesla do this?
|
| [0] https://tradingeconomics.com/china/wages
| majormajor wrote:
| > But one thing that's hard to deny is that US and European
| car manufacturers are still building on top of previous
| iterations of their vehicles, swapping out a ICE with an
| electric system but keeping the existing systems,
| frankensteining the two together. The article itself makes
| note of it:
|
| Worth noting that the car in the article isn't from a US or
| European car manufacturer, though Hyundai is certainly
| fairly well-established at this point.
|
| But also, a lot of the stuff going on/wiring+subsystem
| count is not solely a factor of "making a motor assembly
| from scratch". For instance the steering wheel lock sensors
| in the article. Or all the safety-related sensors and
| subsystems, let alone all the infotainment stuff and
| related "features" in a modern car... Is BYD doing any
| better at reducing all that sprawl?
| wakawaka28 wrote:
| Bro, Chinese auto factory workers make like $300 per month:
| https://www.reuters.com/business/autos-
| transportation/chinas...
|
| Compare that to US workers making about $30 per hour:
| https://www.bls.gov/iag/tgs/iagauto.htm
|
| As for the engineering costs: I think reusing existing
| designs is a way of cutting costs for US companies. Chinese
| companies and Tesla designed very different stuff from
| scratch because they had no choice I think. Remember,
| existing designs are proven over potentially decades,
| comply with various laws, etc.
| gnatolf wrote:
| And as now Tesla has moved past that early
| 'greenfielding' stage, their situation has changed to be
| dramatically more similar to the 'legacy' car makers. And
| suddenly, Tesla sees that their supposedly superior
| quirky approaches to carmaking generally are probably
| going to 'solidify' into systems eerily similar to the
| legacy ones.
|
| Whoever was dismissive of the legacy car makers was also
| assuming decades of innovations in maintainability
| planning and reuse logic in one of the most highly
| competitive industries. Turns out, Tesla - even though
| the shook up the legacy contenders early on - is losing a
| lot of the advantages quicker that they have imagined to
| stay. Hardly a surprise to anyone who understands that
| millions of highly skilled engineers in the car
| industries aren't exactly less competent than the average
| Tesla engineer.
| wakawaka28 wrote:
| It seems to me that Tesla still makes the best
| functioning EV if you overlook their warts like being all
| proprietary, difficult to repair, and so on. Even the
| best EV sucks compared to an ICE car, and that is
| reflected in demand. Furthermore, Tesla is essentially
| competing with China, which they rely upon for many
| components and which seeks to cut them out of the
| domestic market. I don't think any Chinese EV is actually
| better than a Tesla but it is cheaper for various
| reasons, and that can cut into their market share.
| Remember, the Chinese government is investing heavily in
| EV tech and they basically force their citizens to buy
| the things regardless of how good they actually are. It
| would be foolish to think that they will always suck
| compared to Tesla. The Chinese government is willing to
| lose money to put every Western manufacturing company out
| of business. You can't compete with that, their
| protectionist policies, or even their cheap labor,
| without serious protectionism of your own.
| ponector wrote:
| But do you know US car companies are not paying US salaries
| to people who make cars either? They pay mostly Mexican and
| Canadian rates
| wakawaka28 wrote:
| I read it's on average $30 per hour. I have heard of much
| higher. Anyway, the average Chinese auto worker at BYD
| makes about $300 per month.
|
| https://www.bls.gov/iag/tgs/iagauto.htm
|
| https://www.reuters.com/business/autos-
| transportation/chinas...
| ponector wrote:
| I bet US companies are not paying anything near 30$ per
| hour to the workers of their Mexican factories.
|
| Actually they are paying even less than some Chinese
| companies there.
|
| And your link does say byd offered a base salary 300$,
| with much more as a total compensation.
| elihu wrote:
| Price of labor is part of it, but it's mostly the batteries.
| China is basically the only country that makes LFP batteries
| in high volume. That may be gradually changing (some big
| patents expired not long ago), but it'll take time for other
| countries to ramp up their production if they can even be
| bothered to.
| wakawaka28 wrote:
| We could make more batteries in the US too but higher wages
| and environmental regulations put us at a disadvantage. The
| same applies to practically anything you can think of.
| Animats wrote:
| One would think. But there's a track record of failure
| outside Asia.
|
| American Battery Factory seems to be good at press
| releases but not at shipping product.[1]
|
| Tesla had severe problems with in-house battery
| production. Mostly they packaged Panasonic and CATL
| cells. But the battery plant may be past that point,
| finally.[2]
|
| The only European company that makes LFE batteries in
| quantity is in Serbia, and they're still in the sample
| stage.[3]
|
| These new plants are starting to make a product Asian
| plants have been producing for years. All the big Asian
| makers are frantically trying to get the next generation,
| solid state battery production to work. Some of them have
| semi-solid state batteries working. Factorial in the US
| is trying to do that, too.
|
| [1] https://americanbatteryfactory.com/press
|
| [2] https://insideevs.com/news/733985/tesla-4680-manufact
| uring-m...
|
| [3] https://elevenes.com/en/contact
| wakawaka28 wrote:
| Chinese batteries are all over the place in terms of
| quality. Just because Tesla had problems does not mean
| those problems are insurmountable. They most likely would
| have been figured out all problems if they did not have
| the option to just buy batteries elsewhere. Chinese
| battery companies benefit from cheap labor, lax
| environmental regulations, and government subsidies. I
| think other countries aren't making many EV batteries for
| the same reason they aren't making much of anything else:
| because it isn't possible for them to compete with China
| on cost (yet).
| 7thpower wrote:
| They are genuinely more efficient as a result of ingenuity
| and intense competition. In addition to that, they have the
| entire supply chain on the continent and have become
| incredibly vertically integrated.
|
| I know someone will chime in and talk about subsidies and IP
| theft, and while that may be true, the Chinese manufacturers
| are also incredibly willing to take risks and innovate, and
| that seems to be a reality that we do not want to confront in
| the west.
| wakawaka28 wrote:
| They are fairly efficient but we used to be efficient too.
| We simply cannot compete on cost because wages are so low
| there. Even if we had 100% automation we could not do it.
|
| Let me put it another way. It is literally cheaper to ship
| basic materials like wood to China and have them send us
| back popsicle sticks. Does that sound like a cutting-edge
| efficiency problem, or is it a wage problem?? The same can
| be said about all kinds of things from food to pig iron.
| We're not talking about tech in any sense. The US mastered
| every single industry it sent to China with great
| efficiency, but the exchange rate situation and low wages
| there make it very difficult for a US company to compete.
|
| Also, China protects its markets much better than we do. In
| order to sell in China you have to set up a 51% Chinese-
| owned outfit just to do that. Meanwhile they dump all their
| products on the world market with very few reciprocal
| relationships. Imagine how different things would be if we
| required Chinese companies to do the 51% US-owned franchise
| thing here. We could even require them to build factories
| here. Of course, there is no point doing that. If they did
| it, the goods would be just as expensive as 100% American
| companies. That's why we don't bother. They on the other
| hand do it mainly to swipe whatever knowledge they can from
| foreign companies. I've seen many accounts of this from US
| companies. You can get the Chinese to make lots of things,
| but if you send your design there then you risk knockoffs
| putting you out of business in only a few years.
| cdmckay wrote:
| How do you explain the fact that car manufacturers can
| and do build plants in Mexico and use cheap labour there,
| but still can't compete with Chinese manufacturers?
| Labour cost isn't the problem, the problem is that US
| innovation has stagnated and now his to rely on
| protectionism to compete.
| wakawaka28 wrote:
| I feel like I just enumerated several ways that China is
| overwhelmingly cheaper than practically any other
| advanced economy. But I will try to spell it out even
| more.
|
| Labor is almost certainly not as cheap in Mexico as it is
| in China. China still enjoys benefits of "developing
| nation" status despite being very advanced when it comes
| to manufacturing. There are many variables when it comes
| to productivity such as the amount of investment, the
| size of the workforce, and government subsidies. If you
| believe in specialization, then having a much larger
| population to work (as also consume the product) is a big
| advantage. The Chinese government is heavily involved
| with its domestic businesses, from literally owning them
| to spying on their behalf, to putting up roadblocks for
| any competition. Mexico might be as advanced as China if
| we had outsourced everything to them instead of China,
| but I'm sure that did not make sense when we started
| doing it and it probably still does not.
|
| There's nothing magic about China. It's just got lots of
| people and cheap labor, and a bunch of policies that are
| unfair to the rest of the world. They have a head start
| of about 30+ years on Mexico and other competition. The
| US and euro nations have let everything basically rot for
| 30+ years instead as everything got shipped to China.
| It's not that we can't do anything that they can do in
| principle, but it takes time and investment and the
| result is hard-pressed to make enough money due to the
| fact China can do it cheaper. In most cases Western
| manufacturing was better than Chinese for the longest
| time, but we basically taught them all our trade secrets
| without them sharing back any knowledge. We don't have a
| large pool of workers with manufacturing experience as
| they do, because of the outsourcing.
|
| We have some subsidies, but they pale in comparison to
| what China does and come with random obligations like
| quotas per ethnicity or sexual orientation. TSMC
| complained about this stuff recently. They got billions
| of dollars in subsidies but still struggle to hire the
| right people locally in the US.
|
| It takes decades for some of these industries to build
| up, even going back to the university training pipeline.
| The idea of pushing a "service economy" is a costly
| mistake that nearly all Western countries fell into. At
| some point, China and other manufacturing-based nations
| will refuse to take worthless Western currencies in
| exchange for their goods. That is, unless we have
| something real to offer in exchange.
| Qwertious wrote:
| Their prices are lower because China went all-in on EVs in
| 2010 (as a country, not just their car companies), whereas US
| companies are _still_ flirting with ICE and hybrids _in 2024_
| , and woe betide any US politician who advocates making it
| harder to register an ICE vehicle.
|
| Labor prices matter, but 14 years of dithering matters more.
| Animats wrote:
| > woe betide any US politician who advocates making it
| harder to register an ICE vehicle.
|
| Right. Try to register an ICE car in Beijing.[1]
|
| [1] https://www.electrive.com/2024/07/25/beijing-increases-
| nev-q...
| wakawaka28 wrote:
| ICE and hybrids are still essential. Toyota estimated that
| EVs were going to be unsuitable for 75% of the US market.
| They aren't idiots. The car companies are making what
| people actually need. We don't have charging or electric
| infrastructure to support everyone having an EV, and there
| are many fire safety issues yet to be resolved for that to
| work.
| ThePowerOfFuet wrote:
| They will be unsuitable because of that dithering
| resulting in, among many other things, poor charging
| infrastructure.
| wakawaka28 wrote:
| We don't even produce enough electricity for EVs, and now
| we are trying to power AI data centers poised to take
| even more power. It's not just a distribution problem, or
| a charging facility problem. It is an electricity
| production problem. The problem of producing power and
| distributing it alone will likely take 10-20 years to
| solve. Charging infrastructure is a different beast
| because it generates huge loads on the power grid in
| short bursts. Many big charging stations run massive
| diesel generators and/or have HUGE batteries on site to
| handle this load. Then there is the fire hazards, toxic
| mining for batteries, chemical pollution from batteries,
| and the long charge times. A lot of people live in
| apartments where home charging will never be feasible. On
| top of all of this, smart chargers are being designed to
| "handle" grid issues by turning off charging or even
| sending your electricity back into the grid which will
| leave you wondering "Why can't I use my car? It's been on
| the charger a stupid amount of time now..."
|
| In summary, I won't be hopping on the EV bandwagon. The
| Toyota CEO is right. They have nothing against EVs and
| would make them if it made sense. Trying to ram EVs down
| people's throats will waste a lot of money and cause lots
| of problems. A hybrid is something that actually does
| work for many people. Hydrogen would also be superior, if
| they can get the kinks out. Toyota is a pioneer in
| hydrogen power too.
| Schiendelman wrote:
| It's pretty disingenuous to argue that's why they are price
| competitive when there are so many bigger factors.
| pas wrote:
| can you please elaborate on this? what are these factors? how
| do we know which factor contributes how much? thanks!
| hawaiianbrah wrote:
| The support they get from the Chinese government ...
| bryanlarsen wrote:
| BYD et al got massive support from the Chinese government
| in the past, but most of that support is gone now, and
| little of what is left applies to exports. The US
| government's $7500 rebate is larger than what BYD gets
| per car.
| Schiendelman wrote:
| We don't know that at all.
| bryanlarsen wrote:
| We know it is 17% or less, because of the EU
| investigation.
| Qwertious wrote:
| It's easier to register an EV in China than an ICE car,
| among other things - for instance, ICE cars must be left
| idle on a specific day of the week (determined from the
| car's license plate number), whereas EVs can be used the
| full 7 days a week.
| amrocha wrote:
| That's not support from the chinese government, that's
| just good climate policy. Sucks that EVs in the US are
| held back by the government's poor climate policy.
| CrimsonRain wrote:
| The biggest factor is how complacent these car companies have
| been for years to throw away all the quality and prestige
| associated with their brand name, and the lead they had over
| Tesla and other ev focused companies. It is hilarious how bad
| offerings from Audi/bmv (VW is too shit to compare) compared
| to Tesla simply because the dinosaurs didn't wanna reimagine
| their build process. They actually can't even if they want
| to; unions have them by the throat. And Chinese companies
| have the benefit of watching Tesla, learning (and stealing)
| from Tesla and others + lower wages. Legacy automakers can't
| even compete with Tesla; how will they compete with Chinese
| ones?
| beAbU wrote:
| If you read the earlier articles in this series you'll see that
| the motor, diff, motor controller, charge controller and
| inverter are all on a single 'stack', treated as a single unit
| in the car. This module is used in the Hyundai Kona, Kia e-Niro
| and Soul EV.
|
| Modular car design is nothing new and almost all carmakers
| thesedays do this.
| cwalv wrote:
| > So the controller only ever increased the torque request, or
| kept it at the same level. Even when I simulated pressing the
| brake it was like "Nothing needs to change, we're not even
| moving!"
|
| So wheel speed sensors drop out and the car will accelerate
| uncontrollably? I love EVs, but with all this complexity I wish
| there's some kind of mechanical disconnect or a big red STOP
| button somewhere.
| trhway wrote:
| >the car will accelerate uncontrollably?
|
| https://en.wikipedia.org/wiki/2009-2011_Toyota_vehicle_recal...
|
| 'Michael Barr of the Barr Group testified[30] that NASA had not
| been able to complete its examination of Toyota's ETCS and that
| Toyota did not follow best practices for real time life-
| critical software, and that a single bit flip which can be
| caused by cosmic rays could cause unintended acceleration. "
| cwalv wrote:
| Yeah, maybe not particular to EVs. I do remember wondering
| back during the Toyota "uncontrolled acceleration" epidemic
| why people wouldn't just put the cars in neutral
| Syonyk wrote:
| Because the vast majority of people driving cars don't have
| enough of a mental model of the vehicle systems to consider
| such a thing, especially in a panic situation such as
| unintended acceleration.
|
| If you've driven rattletrap manuals for most of your life,
| and have worked on cars, rebuilt engines, replaced
| clutches, rewired things that failed, yeah. That's an
| obvious conclusion, and I expect some people without doing
| that will have enough sense of what's going on to consider
| a drop to neutral (and letting the rev limiter handle
| keeping the engine intact).
|
| But go ask most people, even in technical fields, about the
| details of a car, and you'll struggle to get much beyond "I
| press the gas and it goes." You run into this constantly if
| you're a "car guy" and people ask you questions about why
| their car isn't going. "It turns over but doesn't start!"
| can mean anything from "the lights are barely on and
| nothing happens" to "the starter relay clicks but nothing
| happens" to what I would consider that to mean, "the engine
| is rotating under the starter's power but is not engaging
| in sustained internal combustion."
|
| Neutral isn't a thing most people even think about,
| unfortunately. Park, Drive, Reverse, and some oddball other
| positions that you don't want to end up in accidentally.
| Yes, they're useful, and yes, they solve problems, but it's
| not something that a lot of people would consider. Neither
| do they seem to consider "Stand on the brakes until the car
| comes to a stop. No, really, _stand_ on them! " - because
| I've yet to meet a moderately well maintained vehicle that
| can't come to a stop with the gas floored and the brakes
| applied firmly (yes, I've tried, it's a standard test of
| mine after brake work). But if you only apply partial brake
| pressure, or have a vacuum brake booster, you only get a
| few attempts before the booster has lost vacuum (won't get
| any more, because wide open throttle), and if you've heated
| up your brakes trying without succeeding, you may very well
| have no usable brakes left. Passenger car brakes are
| adequate, but you can easily overheat them and fade them if
| you try, or boil the fluid, or... etc. Again, not something
| you'll find many people aware of these days.
|
| I wish it were different, but "magic box I put gas into and
| it goes" is closer to the reality of how many people
| consider cars these days.
| Arch-TK wrote:
| Even people who know about the solution might find it
| drops out of their brain in a moment of panic.
|
| I locked myself out of my house recently, and it was only
| after scaling to the 1st floor, breaking in through an
| open window, and breaking through a locked interior door
| (the house had been secured as I was going on a trip, and
| the only things I forgot were my keys and that window),
| that I remembered that there was a spare key in my car
| (which was open). This moment of clarity coincided with
| the stress going away.
| Syonyk wrote:
| Again, it depends a lot on your experience with vehicles.
| I expect someone who had driven a manual for a long while
| (or even learned on one but hadn't driven one recently)
| would be radically more likely to come to "Oh, select
| neutral" as a solution than someone who has only ever
| driven automatics. "Neutral" is far more part of "life
| with a manual" than it is with automatics - I would be
| willing to bet that a substantial fraction of automatic
| transmissions have never been deliberately put in
| neutral.
|
| My daily driver has an archaic manual sequential
| transmission (2005 Ural - sidecar motorcycle sort of
| thing), and I select neutral at every stoplight I'm
| likely to be at for a while to avoid wearing the clutch
| bearings. Also, I have to most of the way double clutch
| my shifts on that bike (pause in the false neutral
| between gears) to avoid too much clashing. If I had a
| runaway throttle condition (certainly possible), I have
| at least three instant methods I'd use (kill switch,
| clutch, and rock it into a false neutral). But I've spent
| most of my driving career with such things, and vehicles
| that _don 't_ have those are a bit of a novelty to me.
| mkesper wrote:
| Also my Toyota Auris Hybrid has a weird kind of joystick
| for changing gear and putting it into neutral position
| requires holding that position for some time. Gave me an
| unpleasant (but luckily harmless) event in a car wash
| where you're required to have power on but use neutral
| position with automatic gearing.
| 01HNNWZ0MV43FF wrote:
| Random aside, I set my automatic in neutral while setting
| the parking brake, to let it rock into place
| jval43 wrote:
| On a manual it's the opposite. Put it in 1st gear, let it
| settle into place, only then parking brake.
|
| 1st will hold the car by itself if the parking brake
| slips.
| grecy wrote:
| That works until it doesn't. When my poorly adjusted and
| full of mud parking brake finally failed The weight of my
| Jeep overcame engine compression and rolled the engine
| over while it was in first. It got going surprisingly
| fast until it smacked into a rock wall and flipped the
| Jeep on its side. This was in remote Uganda.
|
| Video from immediately after it flipped over
| https://m.youtube.com/watch?v=DChDTGIciNI
| spockz wrote:
| Would it have helped to put it in second? If this the
| case. Why don't we put the car in highest gear instead of
| first?
| grecy wrote:
| No actually, first gear low range 4x4 would be better -
| and that's what I do now.
|
| Think of how much effort it takes to pedal a bike from
| standstill in 1st gear vs the highest gear. The force
| required is the same if it's being applied to the wheel
| and turning your legs (the engine)
| sokoloff wrote:
| You want the car to have the least leverage against the
| engine, not the most.
| avar wrote:
| Shouldn't you put it in reverse on a forward incline, not
| 1st?
|
| And turn the wheels such that even if it got going it
| would be stopped by terrain? That should be especially
| easy on unpaved African roads.
| grecy wrote:
| Reverse is troublesome, because if it does roll the
| engine over it will turn the engine backwards. While that
| shouldn't cause damage, it's still not great. I actually
| felt it doing so once while sitting in the drivers seat.
| I could feel it turning over one cylinder at a time , one
| every 5 seconds or so.
|
| Using the terrain is my preferred option, but then I
| didn't have that choice
| jaredhallen wrote:
| I don't think there's any particular problem with
| rotating the engine in reverse while it's off, but on
| most manual transmissions that I'm aware of, first and
| reverse ratios are pretty similar, so likely not much to
| be gained.
| grecy wrote:
| > _I don 't think there's any particular problem with
| rotating the engine in reverse while it's off_
|
| I agree, _in theory_ it should be fine.
|
| Driving a lap around the African continent is not the
| place to test that theory.
|
| I just looked it up, my Jeep has the NSG 370 6 speed box
| behind the old 3.8ltr V6.
|
| 1st is 4.46
|
| Reverse is 4.06
| myth2018 wrote:
| > Even people who know about the solution might find it
| drops out of their brain in a moment of panic.
|
| I agree. During a period of huge storms in my region I
| kept mentally preparing for getting caught in a flood:
| engage first gear, press the gas and go, slow and steady.
|
| Then my fears materialized and as soon as the flood
| started pushing my car, I pressed the clutch and engaged
| the second.
|
| Thankfully I realized it fast enough, kept pressing the
| gas and engaged back the 1st, so my mental training may
| have helped, but that was a close call.
| cwalv wrote:
| That makes sense in most cases, but I remember there
| being multiple cases where people had the composure to
| call 911 and report the situation.
| eru wrote:
| Compare https://en.wikipedia.org/wiki/2009%E2%80%932011_T
| oyota_vehic...
|
| If people think they are hitting the brakes (but are
| accidentally hitting the gas), then hitting the 'brakes'
| harder will make the problem worse.
| idunnoman1222 wrote:
| People that did put their car in neutral didn't make the
| news
| bsder wrote:
| 1) Because panic is a thing.
|
| You need _training_ to guarantee correct reaction when
| things go wrong.
|
| Here's an anecdote: I used to drive a car with a standard
| transmission in Los Angeles. In quite a few places, the
| parking spots have a "trench" in the front for drainage.
| So, you can place your car in reverse, release the brake
| and have your car roll forward quite a bit (the trench
| makes an even stronger downward slope on a hill that is
| already pointing downward) before the clutch engages. A bit
| surprising but nothing that weird for someone who drives a
| stick.
|
| Now, have that sequence happen to someone driving a car
| with an automatic transmission. They shifted to reverse,
| the car is rolling forward more than they expect and is on
| a hill, they hit the gas to arrest the roll, the
| transmission engages and the car _shoots_ in reverse. Pray
| that there isn 't anything close behind them or they're
| going to run over a pedestrian, put their car through a
| wall, etc.
|
| 2) Because the majority of the people who had "uncontrolled
| acceleration" were old.
|
| The vast majority of the cases were very likely driver
| error by older drivers who had incorrect habits ingrained.
| Toyota probably would have won the case if this was the
| only issue.
|
| Alas, Toyota lost the case because their processes for
| safety were such a complete shitshow that they were going
| to get _destroyed_ in court.
| jval43 wrote:
| EVs (and hybrids) solve that problem so elegantly.
|
| They have so much torque at a standstill that hill assist
| is a given and going up or down a hill slowly forwards or
| reverse is not an issue. Absolute gamechanger.
|
| Not sure what you mean by standard transmission, but in a
| manual you'd also have to use the parking brake while
| using the clutch to go up in reverse. Otherwise the motor
| would stall, or you'd roll forwards.
| aaronmdjones wrote:
| This is why I'm so glad I have a manual transmission with a
| physical ignition key.
|
| Car starts accelerating out of control? You have several
| options that you can try in no particular order (except the
| first one, which should always be tried first).
|
| Lift your primary foot to confirm you're not accidentally
| pressing the accelerator instead of the brake (this is
| surprisingly common). Dump the clutch with the other foot
| at the same time.
|
| If the engine is still going nuts, shift to neutral and/or
| turn the ignition off (DON'T remove the key yet; that will
| lock the steering wheel, which is a bad idea when you're
| still moving). Coast to a stop somewhere safe; your brakes
| will also still work for a while. You won't have power
| steering, but you won't need it. Remove the key -- this
| WILL kill the engine (if you didn't already switch off).
| You're done.
|
| My driving instructor did this to me in an empty
| supermarket car park. Then he did it again until I got the
| hang of it. It's a valuable learning experience.
| myself248 wrote:
| I'm still not sure whether it applies to this case, but on
| the Prius at least, "neutral" is a software concept. There
| is no physical linkage from the drive mode selector
| ("gearshift") to anything mechanical, and there are no
| mechanical components that could uncouple the powerplant
| from the wheels. Putting the powertrain in neutral is
| accomplished by removing torque commands from the electric
| motors, at which time the engine and wheels can free-spin.
|
| At the time this was in the news, I was never able to find
| a coherent explanation of whether any such bit-flip
| affecting some piece of software on some module, would also
| inhibit the interpretation and implementation of a neutral
| drive mode selection.
| thescriptkiddie wrote:
| I feel like if you can't come up with the idea to try
| pushing in the clutch, shifting into neutral, turning off
| the key, or applying the handbrake within ten seconds you
| should have your license taken away. and if you design a
| car where those things wouldn't work you should go to
| prison.
| rocqua wrote:
| This was on automatic shifting cars.
| thescriptkiddie wrote:
| I don't have a lot of experience with automatic shifting
| cars, but I believe that they still have neutral, keys,
| and handbrakes. If they don't then their designers should
| go to prison.
| Doxin wrote:
| If the wheel speed sensors drop out they put nothing on the CAN
| bus, not a "0 speed" message. I think it's pretty safe to
| assume the controller logic here has a fairly strict timeout on
| how often it wants to see wheel speed messages.
| Retr0id wrote:
| There is presumably still _some_ possibility of them failing
| in an "always reports 0" way
| lostlogin wrote:
| ...Like when dismembered and spread across a bench.
| Arch-TK wrote:
| It's not unthinkable that whatever transducer takes
| rotation and turns it into a signal which is processed by
| an MCU and translated into CAN messages could get stuck
| producing one signal and trigger such a scenario without
| the car's control system needing to be on a bench.
| 0_____0 wrote:
| There are some parts of engineering in safety systems where
| you have a single thing that could go wrong that would have
| serious consequences, and the result of the FMEA is that
| "it has to not do that".
| zardo wrote:
| I don't think you'll find a wheel speed sensor without a
| few "outputs incorrect speed" failure modes.
| 0_____0 wrote:
| Detectability is one dimension of an error, and "bad
| wheel speed" has decent detectability I reckon - either
| through redundancy, grey codes, index pulse checking,
| bound checking.
|
| Also the issue experienced in the post wasn't an issue
| with a sensor per se.
| throw88888 wrote:
| Sure, it is possible theoretically.
|
| However, most relevant regulation (IEC61508, ISO26262,
| DO-178X) requires that systems controlling machines in
| automotive, rail or aerospace have a possibility of
| dangerous faults lower than 10^-9 (over the expected
| lifespan).
|
| Many critical control systems like this are formally
| verified and/or extremely well-tested and have redundancy
| in both software and hardware.
| qingcharles wrote:
| This is a video of a driverless car getting rear-ended, and
| doing who-knows-what damage to its electronics; it then goes
| rogue at max speed through the streets smooshing whatever is in
| its path:
|
| https://x.com/PicturesFoIder/status/1832940173400699255
|
| (apologies -- not sure of the best Twitter passthrough to use)
| croisillon wrote:
| Especially since each link to Xitter forwards a couple times
| to itself and messes the browser history... One popular
| option is to use the Nitter instance xcancel.com
| blashyrk wrote:
| I am completely ignorant of all things automotive. I was
| under the impression that any relatively recent (15 or so
| years) ICE car also operates by way of a car computer, and
| that stepping on the gas pedal is just a way to politely
| instruct the computer that you would like it to apply
| throttle. And that for even more recent cars this also
| applies to braking (since the newer cars can brake
| automatically). Have I got it all wrong?
|
| If not, what's stopping a "traditional" (ICE) car from
| (mis)behaving in a similar fashion in some catastrophic
| circumstance that would damage its computer?
| left-struck wrote:
| You're sort of right in your assumption but there's a lot
| of context missing. First, the time period is more like 30
| years for cars having engine control units (ecu), but most
| car up until 10 years ago or so had hard physically wired
| throttles where you stepping on the throttle pulled a
| physical cable. If that cable doesn't get pulled the engine
| doesn't get enough air to go really fast no matter what the
| ecu tries to do. More recent cars have fly by wire
| throttles meaning they are like electric cars in that
| sense.
|
| An ecu has a far more complicated control algorithm than a
| electric motor controller. If it were suddenly damaged it's
| more like that the engine would fail to run at all then run
| out of control because the ecu needs to control the
| airflow, fuel and spark position for the engine to run, if
| any of those fail to work, or stop firing at the right the
| exact time they are required the engine will just stop or
| run very poorly. I actually think this is true of electric
| vehicles too, it's far more likely to stop the motor
| working than to have it run out of control, unless a wheel
| speed sensor is damaged or something.
|
| A petrol car can be placed into neutral if all else fails,
| the engine will run out of control but the car wont. Also
| the gearbox controller is typically a different computer
| from the ecu.
|
| The brakes on any car should be able to over power the
| engine. This is not a challenge for 99% of petrol cars
| because the torque they output is tiny compared to what a
| brake system can apply to the wheels. If you slam on the
| brakes the engine doesn't even come close. Idk about other
| countries but in Australia this also applies to electric
| cars that are road legal, it's a requirement.
|
| the ecu is usually located in the passenger cabin or
| sometimes next to the battery quite deep inside the engine
| bay.
|
| The only thing that would cause a petrol engine to really
| go out of control would be if it was fly by wire throttle
| and that throttle position sensor was broken in the
| particular way that it's reading as full throttle. Idk if
| manufacturers do this but it wouldn't be hard to design a
| fly by wire throttle that when it fails the ecu will see it
| as closed not open.
|
| Anyway I don't think it's much of a concern for electric
| cars either tbh.
| grecy wrote:
| I once had a diesel engine runaway (google it, the engine
| ran on its own oil at some insane rpm). I put it in
| neutral until the engine seized. Scary stuff
| Szpadel wrote:
| why not put it on max gear with brakes fully pressed? it
| should not have enough power to continue
| eptcyka wrote:
| The correct course of action is stuffing up the air
| intake to suffocate the combustion, if this is still a
| viable option. Otherwise, depart from the vehicle and be
| ready to call the fire department.
| grecy wrote:
| I should have done that, hoping to stall the engine. I
| panicked and really didn't know what to do. The noise and
| MASSIVE cloud of black smoke pouring out the back were
| terrifying. Not a great first drive after an engine swap.
| boricj wrote:
| > most car up until 10 years ago or so had hard
| physically wired throttles where you stepping on the
| throttle pulled a physical cable.
|
| More like 25 years ago, at least in France. The 2001
| Renault Clio 2 I'm driving has throttle-by-wire, the
| newest car I personally know of with a mechanical
| throttle is a 1998 Peugeot 205, the last model year of a
| car that debuted in 1982. I doubt any European car
| manufactured after 2001 has a mechanical throttle, if
| only because of European emission standards.
|
| > The only thing that would cause a petrol engine to
| really go out of control would be if it was fly by wire
| throttle and that throttle position sensor was broken in
| the particular way that it's reading as full throttle.
| Idk if manufacturers do this but it wouldn't be hard to
| design a fly by wire throttle that when it fails the ecu
| will see it as closed not open.
|
| On the Clio 2 car, there are two redundant linear
| potentiometer tracks. If the dual measurements don't
| match or if either sensor is disconnected, the ECU will
| default back to a slightly higher than idle throttle.
| lmz wrote:
| Nothing. https://en.wikipedia.org/wiki/Sudden_unintended_ac
| celeration has a list of cases, some of them ECU related.
| t0mas88 wrote:
| Brakes are not usually "by-wire" on a car that is able to
| automatically brake. The brake pedal is still physically
| connected to the brakes.
|
| Same for the steering. BMW for example has a method where
| the steering wheel is physically connected but the computer
| can add corrections to it via a clever set of gears. See
| here: https://en.wikipedia.org/wiki/Active_steering
|
| If the computer (or electric steering motor) fails the
| steering wheel still works.
| angusgr wrote:
| > So wheel speed sensors drop out and the car will accelerate
| uncontrollably?
|
| No, I don't think any of my bench tests suggest that for this
| car. The torque is minimal throughout, so if the motor was
| pushing an actual car then it might not move at all. If it did
| move, even a light touch on the (mechanical) brake pedal would
| stop it.
|
| My problem is that I had a bench setup with no load on the
| motor and no mechanical brake. I could have pulled the safety
| interlock (all EVs have these for emergency first responders)
| but this stops the motor at all costs - wasn't sure of
| potential damage to the motor controller circuitry from back
| EMF.
| foobarian wrote:
| Huh. It just occurred to me that our EV has no mechanical
| mitigation at all. No physical handbrake, no clutch, no
| mechanical key to power off the engine. I'm not sure how to
| feel about this.
| speedgoose wrote:
| You have brakes.
| ZeroGravitas wrote:
| Seems only a matter of time until Chinese manufacturers start
| providing kits for EV conversions. Can they compete on price and
| convenience with equipment rescued from scrapped EVs? Would EV
| tariffs apply?
| sandermvanvliet wrote:
| Check out what https://www.edisonmotors.ca/edison-pickup-kit is
| doing
| spockz wrote:
| Very nice. I really would like to get a replacement kit of my
| XC90 battery and electric engine. Especially one that doesn't
| cost more than half of the remainder of the economic value of
| the car. This is my second second hand plug in hybrid that
| loses battery capacity rapidly and the battery is crazy
| expensive to replace. Moreover, newer generations have
| stronger electric motors giving wider range of use and better
| regen.
| driverdan wrote:
| I'm rooting for Edison but after watching some recent videos
| on this kit I don't have high hopes. There are only a few
| people working on this project.
| ggreer wrote:
| It's quite difficult to convert a combustion engine vehicle to
| an EV.
|
| - EVs need significant volume for batteries. The only places
| available in a combustion vehicle are the engine bay and the
| gas tank. If you put batteries in the engine bay, you'll mess
| up the weight distribution. The volume occupied by the gas tank
| isn't nearly large enough to house a battery for decent range.
|
| - The extra weight of the batteries requires changes to the
| suspension and tires.
|
| - EV motors have lots of torque. If you use the original
| transmission, you'll need to limit torque based on which gear
| it's in. Any replacement transmission will need to be designed
| for that car chassis. It's not easily adapted to other models.
|
| - Combustion vehicles are designed with an accessory belt in
| mind. The air conditioning, power steering, and many other
| components are run off of these belts. An EV motor doesn't spin
| while idling. These components will need another power source,
| or they'll have to be replaced with EV-specific components.
|
| - Combustion vehicles use waste heat from the engine to heat
| the cabin. Unless you live in a mild climate, a retrofit will
| need electric heating coils (or a heat pump for maximum
| efficiency).
|
| And after making all of these modifications, you'll need to
| deal with regulations around making sure the vehicle is street
| legal. Those can differ greatly based on the state and the
| model year of the vehicle you're converting. Considering all
| that, it's unlikely that you'd save money by converting an
| existing vehicle.
|
| An EV kit car might make more sense, but the market for those
| is quite small.
| ZeroGravitas wrote:
| There's already a small market for this in classic cars and
| they've worked most of these things out even to the point of
| installing heated seats, writing their own software, making
| and selling kits for common target cars etc.
|
| It's just mostly based on salvaged Tesla motors and batteries
| as far as I can tell.
|
| (I think Jaguar and Ford talked about selling EV crate
| engines for their older models but I've not heard about that
| for a while)
| Qwertious wrote:
| Classic cars don't make sense, though - if you're driving
| e.g. a Ford Model T, then you just objectively don't care
| about performance or cost effectiveness.
| driverdan wrote:
| Check out Electric Classic Cars on YT:
| https://www.youtube.com/@ElectricClassicCars
|
| Most of their conversions are sports cars but many
| aren't.
| piuantiderp wrote:
| Electric are no bueno for those 2 metrics
| lazide wrote:
| Classic cars are the perfect example of a hobbiest niche -
| where practicality is often literally a negative.
|
| Frankly, if it's common in Classic Cars, it's probably not
| a good idea to do it in a production vehicle/practical
| situation.
| Kirby64 wrote:
| > EVs need significant volume for batteries. The only places
| available in a combustion vehicle are the engine bay and the
| gas tank. If you put batteries in the engine bay, you'll mess
| up the weight distribution. The volume occupied by the gas
| tank isn't nearly large enough to house a battery for decent
| range.
|
| You're forgetting: exhaust and transmission tunnel (for
| RWD/AWD cars). Just those two areas alone are a substantial
| amount of space. Add in space in the sub-trunk area (that
| might have a spare tire, or just free space)... and you can
| cobble together quite a bit of capacity.
|
| > EV motors have lots of torque. If you use the original
| transmission, you'll need to limit torque based on which gear
| it's in. Any replacement transmission will need to be
| designed for that car chassis. It's not easily adapted to
| other models.
|
| Why would you use the existing transmission? Just use the
| transmission built into the EV motor... they all have them.
| phibr0 wrote:
| .
| AtlasBarfed wrote:
| - battery significant volume: this depends on intended range,
| and if sulfur chemistries hit the market you can probably
| drop the required volume by 40-70%.
|
| - extra weight: see above, and removing engine and other
| components
|
| - yes the EV motor will need to be aware, that's a control
| issue not some physical issue
|
| - another power source.... like, a battery bank?
|
| - waste heat for AC: heat pumps
|
| Yeah, I know I am massively handwaving. It's a really hard
| problem, but some EV retrofit for "incumbent" cars
| (eventually to be "classic") would save a lot of carbon.
|
| But it's not going to happen, it's too labor and skill
| intensive. Capital hates everything that is labor/skill
| dependent. It might be able to be assembly lined to some
| degree: common car platforms of major manufactures would
| help. The engine lift isn't THAT bad for many platforms, the
| hood removal - bolt loosen - engine lift could be done in 3-4
| "disassembly line" steps.
|
| EV motors are pretty compact from what I can tell, so the
| engine compartment can probably accommodate enough high-
| density (sulfur chemistry in 5-8 years) batteries to get a
| 150-200 mile range.
|
| The REALLY OPTIMAL conversion target should probably be a
| swapout with a hybrid drivetrain, if we could get a compact
| rotary recharge engine developed combined with a compact EV
| motor. The transmission interface is still a PITA, but the
| heat excess and other things might be conserved better, and
| there might be room left over for 50 miles of all-electric
| range.
|
| That would deliver 90% all-electric trips in-city, regen
| braking, but keep ICE power for all the legacy accessories.
|
| We should have been working collectively on hybrids within a
| couple years of the Prius being released in the late 1990s.
| We should have forced all auto manufacturers to have hybrids
| for all cars in 10 years (regen braking and city efficiency
| would have been 20% gas savings right there, maybe more).
|
| Then 10 years after that have forced plugin hybrids with
| increasing thresholds for all-electric range.
| Cthulhu_ wrote:
| That would be a major operation, basically a rebuild of a car,
| plus you'd need all the relevant controls etc rewired too. It
| wouldn't be worth it, not when this same China is investing
| heavily in affordable EV mass production.
| ActorNightly wrote:
| EV conversions aren't gonna catch on due to the complexities of
| removing everything from a ICE car.
| schiffern wrote:
| If you're interested in this check out the previous posts:
|
| Part 1 https://www.projectgus.com/2023/03/ev-conversion-one/
|
| Part 2 https://www.projectgus.com/2023/03/ev-conversion-two/
|
| Part 3 https://www.projectgus.com/2023/10/kona-can-decoding/
|
| ...and the follow-up posts:
|
| Part 5 https://www.projectgus.com/2024/04/unremarkable/
|
| Part 6 https://www.projectgus.com/2024/10/simplifying-bench-kona/
| krisoft wrote:
| I heard a similar story from a coworker. They were interfacing
| with a car via CAN. They had an engineer from the manufacturer
| telling them the details of the message they should be sending to
| demand a certain speed. Turns out the description wasn't quite
| right. The message ID was correct, but not the endianness of the
| speed demand signal.
|
| Thus when they tried to test it they thought they requested a
| stately 5m/s, but the vehicle thought they were asking it to
| exceed the speed of sound. Which of course it wasn't designed to
| be able to do, but it still tried.
|
| That's why i prefer to have nice hardware e-stops on prototype
| vehicles.
| m463 wrote:
| > That's why i prefer to have nice hardware e-stops on
| prototype vehicles.
|
| Yeah, I kind of wonder if lawsuits/regulation might be the way
| to get those.
|
| Because there will always be some sort of cost with that kind
| of thing.
|
| I'm pretty sure a major reason garage doors have limit and
| occlusion sensors is because of regulation. (and even those
| suck - it is common for garage doors to incorrectly sense
| occlusion in bright sunlight)
| krisoft wrote:
| > I kind of wonder if lawsuits/regulation might be the way to
| get those.
|
| I'm talking about prototype cars. The solution there to have
| an e-stop is to ask your technicians to put it on. No lawsuit
| or regulation is necessary for that.
|
| If you are thinking about mandating e-stops on production
| vehicles then I don't think that is the right thing to do. It
| is a complicated analysis but it boils down to that the cases
| where it would help should be vanishingly small, and even in
| those people not trained for it would forget to use them.
|
| > there will always be some sort of cost with that kind of
| thing
|
| Absolutely. And the cost of the switch is not the major
| component. Where i work forgetting to reset the e-stop is so
| common that it is the first thing we ask about when something
| is weird. And the people forgetting them are skilled
| engineers with known prototype cars. I imagine the cost of
| support/service calls would be huge in prod.
| bewaretheirs wrote:
| Something similar was at work in the 2018 natural gas
| explosions in and around Andover, MA:
| https://en.wikipedia.org/wiki/Merrimack_Valley_gas_explosion...
|
| "According to the NTSB's preliminary report, customers in the
| accident area received gas from a low-pressure (0.5 psi)
| distribution network which, in turn, was fed from a high-
| pressure (75 psi) main pipeline via regulators controlled by
| sensors measuring pressure in the low-pressure pipes. At the
| time of the accident, workers were replacing some of the low-
| pressure piping, but the procedure set out by Columbia Gas for
| doing this failed to include transfer of a regulator's pressure
| sensor from the old, disused piping to the new. As a result,
| when the old pipe was depressurized, the regulator sensed zero
| pressure on the low-pressure side and opened completely,
| feeding the main pipeline's full pressure into the local
| distribution network."
| echoangle wrote:
| Interesting that they only had a single regulator, if
| overpressure is that dangerous, I would expect them to have
| multiple regulators in sequence or a blowout valve to dump
| excess pressure.
| lazide wrote:
| That will be in the postmortem I'm sure.
|
| In the mean time, that costs money, and since no one
| managed to kill people by being dumb in this particular way
| before....
| bewaretheirs wrote:
| The NTSB final report on this accident is here:
|
| https://www.ntsb.gov/news/events/Pages/2019-PLD18MR003-BM
| G.a...
|
| Unfortunately the shutdown of go.usa.gov broke a bunch of
| links from that page, but the NTSB recommendations are
| summarized starting on page 33 (PDF page 44) of https://w
| ww.ntsb.gov/investigations/AccidentReports/Reports/...
|
| But the recommendations to the gas company included:
|
| > Review and ensure that all records and documentation of
| your natural gas systems are traceable, reliable, and
| complete. (P-18-7) (Urgent)
|
| > Apply management of change process to all changes to
| adequately identify system threats that could result in a
| common mode failure. (P-18-8) (Urgent)
|
| > Develop and implement control procedures during
| modifications to gas mains to mitigate the risks
| identified during management of change operations. Gas
| main pressures should be continually monitored during
| these modifications and assets should be placed at
| critical locations to immediately shut down the system if
| abnormal operations are detected. (P-18-9) (Urgent)
|
| Edit to add:
|
| This page has currently working links to the specific
| recommendations:
|
| https://www.ntsb.gov/investigations/Pages/pld18mr003.aspx
| t0mas88 wrote:
| Indeed. Not having a mechanical blow out set a bit above
| the never exceed pressure sounds like a design fault.
| mindslight wrote:
| If you're just talking about when something in a feedback
| loop gets disconnected (causing the output of the error
| amplifier to go to an extreme), you can do this with cruise
| control and a manual transmission (at least on some cars).
| Engage cruise control on the highway, then pop the car out of
| gear without using the clutch (so cruise control doesn't
| disengage). As the car's speed drops, the cruise control
| applies ever more throttle making the RPM shoot up. I've also
| done this going downhill with the car naturally gaining speed
| (and RPM going to idle).
| bewaretheirs wrote:
| Huh. I've owned a few manual-transmission cars over the
| years and they all disallowed this trick -- pressing the
| clutch would disengage cruise control just like a tap on
| the brakes.
| mindslight wrote:
| Yeah, pressing the clutch will do that. But you can pop
| the car out of gear without pressing the clutch. (IIUC)
| the synchros provide some positive holding force that
| holds the transmission in gear, but you can overcome it.
| Also that force goes down with the amount of torque being
| transferred through the transmission, so you can make it
| easier by playing with the gas pedal a bit.
| jeffreygoesto wrote:
| Yup. EStop saved is from the fence when a programmer learned
| that there are "low active" signals on an ECU he war trying to
| convince to follow our acceleration CAN signals. Adrenaline
| time...
| aetherspawn wrote:
| EV software engineer here.
|
| Your hypothesis is basically correct. Since the motor is under no
| load, it will appear to spin out of control even with the
| smallest torque application, but in reality the torque being
| applied is very small... probably around 5Nm.
|
| Trust me if it was truly spinning out of control with no load
| you'd know... it would reach max speed in 0.1 seconds and
| probably start tearing through the floor.
|
| Most likely what's happening is that the creep torque is applying
| a constant small torque and the wheel sensors are reading 0
| continuously, so it continues to apply a constant small torque.
| angusgr wrote:
| Hey! Post author here.
|
| I appreciate the insight from someone who's worked on this kind
| of thing formally, thanks.
|
| > Most likely what's happening is that the creep torque is
| applying a constant small torque and the wheel sensors are
| reading 0 continuously, so it continues to apply a constant
| small torque.
|
| This was also my hypothesis at the time of the post. Turned out
| it's less constrained than this, a fully operational car with
| the drive wheels off the ground will also run away to high rpm
| (even in Neutral):
| https://www.projectgus.com/2024/04/unremarkable/#on-car-test...
|
| There's still minimal torque, as you say, so a small press on
| the car's brake pedal is all it takes to stop. However I think
| if a driveshaft broke on a real car then it'd be spinning fast
| for a minute or two... It kind of makes sense that the control
| loop is tuned for a heavy car with a fixed drive ratio, though.
|
| I am still hopeful there will be a way to stop this behaviour
| via a control signal (rather than pulling the safety interlock
| and slamming the contactors open). Have left the problem aside
| until I have a mechanical brake to use for testing! If that
| doesn't work out then it's still usable I think, provided any
| EV conversion is single speed fixed gear just like the Kona.
|
| If you have any other insights on this then I'd be very
| interested to hear them, though.
| aetherspawn wrote:
| It won't happen on a real car because the speed probably
| comes from the ABS wheel speed sensors, and in that case they
| would read the correct speed of the wheels (unless the motor
| shaft is proper broken).
|
| If the ABS is properly plugged in it will detect a fault with
| the sensors (which probably causes the creep to stop) however
| it won't detect a mechanical fault with the encoder wheel
| (such as sensor not bolted to wheel) -- such a fault is
| indistinguishable from the wheel not spinning, thus zero
| speed.
|
| I think you were emulating the ABS module right? In that
| case, the spinning out of control is actually probably your
| fault. If you had not emulated this, the system would realise
| there is an ABS fault (from the messages not being present)
| and not use the ABS reported speed. It might even fall back
| to motor speed automatically.
|
| Re: shaft scenario, if the motor shaft is broken the safety
| risk is pretty minimal because the torque wont actually cause
| the car to move.
|
| I guess this is what they arrived to in the FMEA.
| aetherspawn wrote:
| Funnily enough I noticed recently that Japanese and Korean
| engineers usually argue against using checksums and random
| magic rolling bytes on these messages ("it will never
| happen"), in contrast Euro engineers use them everywhere.
| In this case the Euro method although more complex would
| have let the system know you are spoofing the ABS and no
| such motion would have happened.
| jeffreygoesto wrote:
| Well. Reading out failure memory from ECUs couple of
| years old showed us that all chechsums failed several
| times over that time...
| Bluecobra wrote:
| It makes we wonder if they have to do it that way, after
| what happened with VW lying about their diesel emissions.
| Dylan16807 wrote:
| > I think you were emulating the ABS module right? In that
| case, the spinning out of control is actually probably your
| fault. If you had not emulated this, the system would
| realise there is an ABS fault (from the messages not being
| present) and not use the ABS reported speed. It might even
| fall back to motor speed automatically.
|
| If the ABS unit getting stuck causes that kind of
| acceleration then I'm going to point most of the fault at
| the control logic.
| aetherspawn wrote:
| Not really.. it will only be applying 5Nm or so which is
| such a small amount of torque that you could likely stop
| the wheel with your hand (equivalent to holding up 500g
| object with 1m ruler)
|
| He is spoofing an ABS message from a working vehicle that
| says "no faults present" on a vehicle that is clearly
| full of faults.
| Dylan16807 wrote:
| > Not really.. it will only be applying 5Nm or so which
| is such a small amount of torque that you could likely
| stop the wheel with your hand (equivalent to holding up
| 500g object with 1m ruler)
|
| It's good that it's small but I'm still not thrilled
| about this control loop.
|
| > He is spoofing an ABS message from a working vehicle
| that says "no faults present" on a vehicle that is
| clearly full of faults.
|
| My point is that the same messages would happen if you
| had a fully working vehicle and then the ABS unit locked
| up in a way that didn't interrupt sending.
| aetherspawn wrote:
| ABS are usually ASIL D rated (ISO 26262) which means they
| have an on board watchdog, redundant processor with
| voting system, etc. so this failure mode (locked up and
| still sending) is considered impossible by design.
| Szpadel wrote:
| sure, but I would think some special case when we expect
| car to have 0 speed to not request any torque from its
| motor. IMO three is no case where car should request any
| torque when been in neutral
| aetherspawn wrote:
| If I had to take a guess why... it probably thinks that
| you're sitting on a hill and doesn't want you to roll
| back.
| numpad0 wrote:
| It's not acceleration, it's torque application. There is
| a slight difference in nuances between those.
| Dylan16807 wrote:
| The problem is that it's doing both when it's only
| supposed to do one.
| numpad0 wrote:
| No, constant torque against nothing is infinite RPM.
| Imagine a space capsule with a stuck roll thruster.
| Dylan16807 wrote:
| Please explain how that is a "no". You just described a
| situation where it would be doing both when it's not
| supposed to. In the analogy, the thruster is supposed to
| turn off once it starts spinning, but it doesn't.
|
| The entire reason this mechanism exists is that
| resistance can be significantly nonzero and needs to be
| adjusted for. It's just doing the adjustment in a flawed
| way.
| numpad0 wrote:
| Sorry if it sounded dismissive, but, I mean, modern motor
| control formulae[1][2] don't have a term for RPM. Motor
| controller derives new output state from just _torque_
| and instantaneous state of the motor, RPM is somewhat
| externally controlled unless that version of formula is
| in use. Hence the capsule analogy: F=ma for constant F
| means a > 0 and (rotational)velocity monotonically
| increases.
|
| It doesn't make instinctive sense to me too that motor
| people haven't been thinking RPM-first for some time, but
| apparently they're not.
|
| 1: https://en.wikipedia.org/wiki/Vector_control_(motor)
|
| 2: https://en.wikipedia.org/wiki/Direct_torque_control
| Dylan16807 wrote:
| > Motor controller derives new output state from just
| torque and instantaneous state of the motor
|
| And the way it makes the motor state advance causes
| acceleration. It doesn't matter what variable goes into
| the formula, especially since you can convert freely. I'm
| pointing at the output and what I find scary about it.
| What comes first doesn't matter, I'd have the same issue
| even if I'm looking at the control formula from a jerk-
| first perspective.
|
| And I don't really see the value of the "against nothing"
| analogy because the reason it's increasing torque is
| because it thinks there's resistance.
| formerly_proven wrote:
| ABS faults can do _way_ more dangerous things than
| indirectly command 5 Nm of torque in a no-load situation.
| Zak wrote:
| I have experienced a spurious ABS activation while
| braking from highway speed on an offramp. It was
| terrifying, and would have led to a crash had there been
| any traffic when I rolled through the stop sign at the
| bottom with the ABS still chattering.
|
| That vehicle got its ABS fuse pulled.
| angusgr wrote:
| > I think you were emulating the ABS module right? In that
| case, the spinning out of control is actually probably your
| fault. If you had not emulated this, the system would
| realise there is an ABS fault (from the messages not being
| present) and not use the ABS reported speed. It might even
| fall back to motor speed automatically.
|
| That's a reasonable expectation, and this got left out of
| the follow-up post I linked, but in the "full car with
| wheels off the ground" tests we actually tried unplugging
| the brake module of an otherwise working car and it didn't
| change anything (including the gradual constant rpm
| increase in Neutral). If anything the behaviour might have
| gotten a little more aggressive with the brake module
| missing.
|
| Have now observed similar behaviour for all three of
| "spoofed brake messages with 0 wheel speeds and emulated
| checksums", "fully operational car with wheels off the
| ground", and "car with wheels off the ground and ABS/brake
| module unplugged". -\\_(tsu)_/-
|
| > Re: shaft scenario, if the motor shaft is broken the
| safety risk is pretty minimal because the torque wont
| actually cause the car to move. > > I guess this is what
| they arrived to in the FMEA.
|
| Fair enough, that makes sense. I guess if that's the case
| then the other behaviour is outside of the scope of what
| they need to care about.
| aetherspawn wrote:
| If you lifted a working car off the ground and it did it
| anyway I'll admit that I'm a little concerned. It should
| stop creeping around 15km/hr.
| angusgr wrote:
| If you're interested then click the link in my first
| reply (which is to a newer post). The first video shows
| the working car reaching 8000rpm (about 80km/h) around
| six seconds _after_ the accelerator was released. The
| second video shows the speed creeping steadily from 38km
| /h to 44km/h (~2600rpm) _after_ switching to Neutral
| (before we got nervous again and touched the brake).
|
| (I don't really understand it, but I also haven't managed
| to think of a safety issue here for normal car use: the
| broken driveshaft is just a bit scary as the motor spins
| unloaded at >10,000rpm for a while. The only other time
| this seems likely to happen is if a mechanic puts the car
| in Drive on a hoist, and it'll stop as soon as they tap
| the brake.)
| dzdt wrote:
| Accident modes for car on a lift in a repair shop, or car
| gets high-centered with drive wheels in the air?
| rightbyte wrote:
| Interesting. Sounds like really bad software.
|
| There should be some sort inertia estimation turning off the
| motor if the inertia don't include the wheels or whatever.
|
| There should also be some check that output axis speed (abs
| sensors) and motor speeds match.
|
| The behaviour sounds kinda dangerous and not up to ECU
| standards.
| aetherspawn wrote:
| We don't implement stuff like this because it would go off
| when you're going down a slight incline for example, and
| the more bandaids you slap on it to get it to work, the
| more complex testing the failure scenario would be.
| Zak wrote:
| > _creep torque_
|
| Tangent: creep is an artifact of how an idling ICE interacts
| with a torque converter. Simulating it on EVs seems like a
| mistake to me, serving only to make them feel more familiar to
| a subset of first-time EV drivers.
| meowster wrote:
| Data point: some ICE vehicles now have settings to turn
| _creep_ on or off.
|
| Source: My mother's 2024 Subaru that I help set up for her.
| Zak wrote:
| The automatic transmissions for all recent Subarus appear
| to use torque converters, which would normally have creep.
| Modern torque converters are much more advanced than older
| ones, so I'm not surprised the option exists to disable it.
| All models except the BRZ use a CVT with fake gears, which
| I find distasteful.
| tonyarkles wrote:
| Heh, I will see your "distasteful" adjective and raise
| you "nauseating". I got a newish Subaru as a rental a
| couple of months ago and found both city and highway
| driving left me feeling slightly disoriented all the
| time.
| AtlasBarfed wrote:
| Specifically automatic transmissions.
|
| Standard/Manual/Stick transmissions don't have creep.
| Zak wrote:
| Automated manuals and DCTs also don't naturally have creep,
| but sometimes it's added in. I imagine that's bad for the
| clutches.
| folmar wrote:
| Creep is needed for tight parking, for example when you'd
| like to move the car 10 cm forward. To simulate driving
| without it, turn on auto-hold and use only accelerator and
| brake for parking -- tight spots become extremely hard.
| HiroshiSan wrote:
| Very cool, I'm in automotive and in school we've got a few of
| these builds with some older engines to play around with.
| numpad0 wrote:
| IIUC, flying orbital altitude over on this domain, treat as
| hallucinations:
|
| High end brushless motors like EV traction motors are "vector"
| controlled and instructed by desired torque, not in sinusoidal
| phase shifts and desired RPM. Back EMF voltages are measured at
| output terminals of drivers, and errors between expected vs
| measured voltages is fed back to the driver thereby achieving
| requested torque, somewhat disconnected from RPM.
|
| This means motor RPM always diverges into +/- infinity with any
| non-zero torque request under no-load condition.
|
| There is another quirk of note, that some EV motors seem to jump
| into an open-loop mode when BEMF or rotor phase detection reports
| failure, and that might also result in unintended acceleration,
| but that's probably not it.
| ActorNightly wrote:
| > the Hyundai Kona Electric is absurdly complicated. More than
| five separate CAN buses, ten or more kilograms of low voltage
| wiring, probably over one hundred electronic modules (most with
| their own CPU and firmware), etc.
|
| This is just sad for electric cars.
| cdmckay wrote:
| Why is it sad?
| holoduke wrote:
| How would you do it otherwise? And btw. Ice cars have probably
| similar amount of modules.
| janosch_123 wrote:
| I've put a Nissan Leaf on a bench before and run it just like you
| did and would never do it again.
|
| This approach is so much harder than it seems. "once everything
| works then it'll be straightforward to remove what's left and
| dramatically reduce the rats nest qualities of this setup" We
| thought the same initially, it turns out the system depends on
| many more components than you would think.
|
| I imagined the EV system to be like an onion where you can take
| layers off, not so!It is much more like an egg, once you smash
| it, you have a few shards that you can re-use but you end up with
| a mess due to high connectivity between systems. (Leaf refused to
| turn on without original power steering and wipers connected).
|
| Surprisingly what is more straightforward is putting together
| your own drivetrain with something like https://openinverter.org
| and building it back up from first principles. Or you isolate the
| inverter and motor and make them believe they are still in the
| original vehicle by replaying CAN messages, ZombieVerter is a
| project with that approach. Both of these are open source
| projects.
|
| Happy tinkering!
| MrGilbert wrote:
| Sounds like the early* days of software engineering, where
| everything was a big bowl of spaghetti you would never untangle
| again, compared to modular applications that you have nowadays.
|
| *rumor has it, that most of the software out there is still
| written like that.
| krisoft wrote:
| > Sounds like the early days of software engineering
|
| Sounds much more like they are trying to work with a
| production system without the source code, the debugers, the
| compilers, the datasheets, and the documentation.
|
| Plus many of the things they want go directly against the
| wishes and good judgement of the engineers who made the
| system. They want to start the car without the steering
| component. I bet that someone at the manufacturer spent extra
| energy that you can't do that. Why? Because under production
| circumstances if the steering components are not answering
| that means that something is terribly wrong with the car and
| it would be dangerous to turn on and accelerate.
|
| Same with the keyless entry component. I bet that there were
| at least an effort done to make circumventing that hard.
| f1shy wrote:
| >> Plus many of the things they want go directly against
| the wishes and good judgement of the engineers who made the
| system.
|
| Never attribute to intelligence what can easily be
| explained by good old stupidity.
|
| I know the automotive industry from inside. It is a miracle
| that cars work at all.
| potato3732842 wrote:
| When one lets a bunch of engineers and managers who share
| your "everything is dangerous and everyone is stupid and if
| my system can't get perfect information I'm going make it
| fail loudly and obnoxiously so somebody fixes me" doctrine
| design a complex product you wind up with unreliably
| garbage because with your attitude every little transient
| imperfection winds up becoming downtime.
| Kye wrote:
| I thought early code was carefully validated on paper with
| flowcharts and review by someone else before you were allowed
| anywhere near an expensive CPU cycle.
| boricj wrote:
| In software engineering, we only ever maintain processes, not
| artifacts. Software modularity when it exists is usually
| extremely coarse and rigid when compared to the malleability
| of electro-mechanical systems.
|
| Got a bug to fix or a feature to implement on a program?
| Modify the source code, run the build system, use the newly
| built artifact and discard the old one. Lose this process and
| you're screwed because the tooling for modifying an extant
| program is still in the Dark Ages. It's not just about
| proprietary software that has reached its end of support,
| given enough time almost any source code tree will bitrot
| past the point where rebuilding it will require a major
| overhaul.
|
| When you need to fix or customize a physical artifact like a
| coffee machine, you usually don't go inside the factory to
| change the blueprints and manufacture a new one. You just
| modify the one you have with standardized tools. It also
| doesn't matter how old the artifact is, even if it's decades
| out of production it can still usually be disassembled and
| put back together as if it was fresh out of the assembly
| line.
|
| The more software bleeds into electro-mechanical systems, the
| less repairable, versatile and hackable they become.
| jiggawatts wrote:
| That's very insightful, and I just wish I had the ability
| to explain this to non-technical managers.
|
| "But it was working!"
|
| "Sure, 10 years ago, now I can't even find a version of
| Visual Studio that will install that can even open the
| project, let alone compile it."
| m3047 wrote:
| History doesn't repeat, it rhymes; and it kind of goes in
| phases or epochs. As Derrida was wont to point out, we show
| up in the middle of things, just flippantly speaking a
| language and carrying on as though the language was something
| we were born with and it's been the same forever because we
| only know our own "forever".
|
| I popped my cherry on VAX silicon, where stack frames were
| baked into the silicon. This meant that regardless of
| language, the stack architecture was a target for the
| compiler not something it constructed. I fell into the middle
| of things: VAX silicon was new, and people wrote in e.g.
| COBOL, FORTRAN, BASIC, Pascal, C because they'd successfully
| done so before and had libraries and practices which had
| stood the test of time and had made the jump to successfully
| infect a new species of silicon.
|
| The successful colonizer libraries and practices had certain
| rules. "You can't manage heap in BASIC" for example, or that
| modular compilation units all had to be written in the same
| language. This is not and never was strictly true, and the
| people writing code knew it; but it was true enough for code
| which jumped silicon.
|
| I on the other hand knew about the silicon stack, and could
| implicitly understand some of the more esoteric compiler
| pragmas for dealing with that stack (intended for cross-
| language linking support) and so by disabling certain linker
| checks and abusing compiler pragmas I could do e.g. memory
| management in BASIC by isolating the compilation unit where
| "memory is an array" from the one where "a memory address is
| an integer" and explicitly telling different lies with
| compiler pragmas in each.
|
| Fast forward a few years and everybody had learned HTML and
| then I'm confronted with somebody wanting me to fix a
| steaming basket of soup machine gun sprayed into different
| files all with "(c) Macromedia" in them. "Where's your no-
| code tool which generated this?" I innocently ask. "Wuuut?"
| is the response. Yea well when you find it, let me know.
| Let's just say the people who have to fix things like that
| probably get paid good money and the solves they come up with
| are comparatively fragile, that code will not (and did not)
| survive; any more than my silicon-aware hacks (which I was
| paid quite well for) for VAX will work on modern silicon.
| Where's all of that shitty VB Wizard code spew? Thankfully
| gone.
|
| Some of these integrations will not be fixable, but some of
| the subsystems will survive, and it might be simply because
| there is no security and it's possible to replay CANbus
| reliably as a result.
| xethos wrote:
| There is a linked update (this one is _months_ old) about how
| much wiring he 's been able to remove, and how few modules he
| has left on the bench. Looks like different OEMs have taken
| different routes regarding how interconnected everything is -
| fortunately for OP, it looks like Hyundai is less of an
| interconnected mess
| angusgr wrote:
| Hi janosch,
|
| Appreciate the heads-up from someone who has been there before!
| Like you I was a bit surprised by how much the integration bled
| across subsystems. I like the egg analogy.
|
| > isolate the inverter and motor and make them believe they are
| still in the original vehicle by replaying CAN messages,
| ZombieVerter is a project with that approach
|
| For sure, great tips. This is what I've been working towards -
| at the time of that post I was spoofing the minimum number of
| CAN messages (still quite a lot), but in the months since I've
| been gradually replacing modules with spoofed signals by
| reversing them one at a time. Some of the follow-up blog posts
| have details about this.
|
| I'm approaching the point of only needing the original motor
| stack (inverter, charger, etc), the original BMS, and all other
| modules spoofed out via CAN messages and a few discrete wired
| signals. The OEM BMS might turn out to be too hard to re-
| integrate once the battery pack gets split apart, but can cross
| that bridge when I come to it.
|
| More blog posts (and open hardware & software) to come, I hope!
| mort96 wrote:
| The removal of the parentheses in the title really changes the
| meaning... The original title focuses on the fact that they got
| the motor to turn, with the addendum that it turns too much. The
| HN title makes it sound like the article is about how the motor
| turns too much.
| HPsquared wrote:
| The constant 5 Nm torque is probably to prevent backlash in the
| driveline when setting off. Best to keep all the gears, shafts
| etc under a slight preload so they don't "clunk" when you start
| accelerating. Much easier on the components, and better comfort.
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