I just built an engine for my car. One thing I gained an appreciation for was how CHEAP cars and engines are. There's probably nothing else with as precise machining that is as inexpensive.
Engine cylinders are honed to accuracies that are less than 1 thousandth of an inch. Crank journals as well and rod journals. This is all precise machine work with metal. I use inches here because in machine work thousandths of inches is the language du jour. Transmissions are similar works of very precise and clean machine work.
The distance between a crank bearing or rod bearing is less than 2 thousandths on modern engines. A small amount of oil in that tiny space is all that keeps your engine from having metal on metal seizure.
So one would think that when EVs reach the same scale they will be significantly cheaper than ICE vehicles.
The raw materials may continue to cost more for EVs. Motor windings are generally copper, and batteries contain lithium and (usually) cobalt and nickel. Permanent magnet motors sometimes contain rare earths.
One could make an EV with aluminum motor windings and electrical cabling, no rare earth magnets, and lithium iron phosphate batteries. That would keep expensive materials to a minimum.
EVs don't need a catalytic converter, so that's a big thing in their favor.
I'm looking forward to mass manufacturing continuing to bring down EV component prices. I think we're a long ways from the point where material costs are the bulk of the expense.
> EVs don't need a catalytic converter, so that's a big thing in their favor.
I feel there is some sort of scam going on with catalytic converters for the last few years. I actually worked in a small family owned auto shop in the early 2000's. If a car came in with a clogged cat, we'd first fix the source of the issue (usually a mis-firing cylinder allowing raw fuel into the exhaust) and then we'd cut out the cat, and weld in a universal fit one that we'd get from the auto store for $20. Then charge the customer $200-$400 for labor. I still see universal fit ones[0] although they are $80 now. But still, if you aren't dumping raw fuel or oil into your exhaust, cats are basically good for 300k+ "normal" driving miles. I assume they are expensive now because they are all mostly specially made/custom fit since all car manufactures keep cramming bigger and bigger engines into smaller and smaller spaces.
And while I'm ranting, there's always a negative for every positive and no doubt for the catalytic converter. For a catalytic converter to convert "greenhouse gases", the engine has to be burning fuel at a perfect air:fuel ratio of 14.7:1. While cruising down the highway, an engine could easily save fuel by running a more lean mixture, but this would cause more "greenhouse gases" to go out. So choose your poison I suppose.
I don't think cats are to address greenhouse gasses; they're focused more on reducing pollutants that affect local air quality and human health.
The main greenhouse gas from a car is carbon dioxide. The amount you create is directly proportional to the amount of fuel you burn.
I don't know why modern cats are expensive; it might have to do with the price of platinum, palladium, and so on, and the relative amount of those materials. A cheap generic cat might have the bare minimum amount of catalyst, and might not do a very good job.
> I don't think cats are to address greenhouse gasses; they're focused more on reducing pollutants that affect local air quality and human health.
I thought the same thing, but interestingly that's only kinda true. If anything, cats increase CO_2 as a desired end goal, because it's better to have CO_2 than CO or NO_x (or so the EPA has decided, I am no where near qualified to decide that). The issue with running too lean is that the reactions in the cat would rather use plain O_2 than NO_x, and so if you have too much O_2 (lean) you won't get rid of any of the NO_x [0]. Before looking into this I thought lean engines produced more NO_x because of higher cylinder temps or something like that (which might be true as well).
Cats not reducing NO_x when lean is essentially why Volkswagen (and practically every other manufacturer has been caught doing similar things to diesel engines) was cheating the test. Diesels have no throttle so they are (almost) always lean, typically very lean.
This does make me wonder, though, does running lean actually increase fuel efficiency? Obviously rich lowers fuel economy because not all the fuel burns, but assuming it all burns what does it matter if you have 1 gram of fuel to 15 grams of air in the cylinder, or 1 gram of fuel to 18 grams of air in the cylinder? You'll still get the same amount of energy, right?
> A cheap generic cat might have the bare minimum amount of catalyst, and might not do a very good job
It depends on the car/engine. My old Mazda RX-8 had a huge cat - longer than the muffler and cost me $2,000 to replace (including labor) back in the late 2000's.
The rotary engine in that vehicle had a terribly difficult time passing California's emission laws even when it was brand new off the lot - which led to strange "hacks" including a blower motor that moved high volumes of air through the exhaust to heat the cat sooner and somehow improve it's numbers, among other things. I assume the extra-long cat was part of the shenanigans Mazda had to go through to get it compliant.
> moved high volumes of air through the exhaust to heat the cat sooner and somehow improve it's numbers
This is because the catalyst works more efficiently at higher temperatures. Emission regs also test vehicles under a cold start. The quicker the cat can be heated up, the quicker it starts working, and that equals fewer total emissions over a given period of operation.
It's funny you mention the RX-8, since I'm in the (slow) process of converting one to electric. That weird cat blower was one of the many parts I removed while thinking "I'm glad I don't have to understand or care about why this car needed something like that in the first place".
Just talking about the RX-8 brings back great memories - what a strange, yet beautiful car!
The cat blower, and the subtle whining sound it made when you started up cold was one of the ways every RX-8 owner was hazed into the fold... after calling the dealer or posting on a forum and finding out it's entirely normal!
Other oddities included how it deliberately burned oil (scaring new owners into thinking they had a serious engine problem), and how you were required to drive it hard to clear out its engine ports (multiple Mazda mechanics confirmed this factoid) - driving it like a normal car would literally clog up the exhaust ports and cause a loss of power (something to do with the lack of moving valves). If memory serves right, it had only 3 (!!!) moving parts in the engine, and was perfectly content to hang out at 9,000 RPM all day - that's incredible.
But, it seems the issues Mazda had maintaining it's emission certifications, and warranty issues with those apex seals (mine had 3 engine replacements over it's lifetime) eventually caused it to be retired. I was sad back then, and still sad we don't have a new improved version - there's really nothing else quite like it out there, not even the RX-7. It really was/is an enthusiast's car.
Good luck on your project - sounds like a fun one!
In theory, it should fix some of the maintenance issues (apex seals are attached to a stationary part of the engine where they can be more easily lubricated) and fuel efficiency / emissions issues (combustion chamber is closer to spherical).
I like the idea of the Mazda rotary engine, but I'm not really surprised they stopped making them, due to fuel economy and emissions. And at them moment, the hundred-thousand mile engine rebuild interval basically means you can get an RX-8 with a bad engine for almost nothing, which opens up a nice opportunity for EV conversion. It's hard to imagine a nicer platform to start from.
Wow, that LiquidPiston rotary looks very interesting! I hadn't seen that before - I too hope it pans out.
> I'm not really surprised they stopped making them, due to fuel economy...
Eh, nobody bought that car for the fuel economy!
The car sold itself... just one test drive and you had to have it. I've owned and driven muscle and other sports cars, and still nothing compares to the RX-8 - it's just such a unique experience.
Not sure how you're doing the conversion, but if you're keeping the carbon fiber driveshaft (vs. a motor on each wheel I suppose), there will be nothing keeping it from screaming off the line with an electric motor under the hood (traditionally the wankel wasn't good off the line with low RPM's, power band kicking in around 6500 if I recall - could make for a great "sleeper"). Although I'm unsure if the driveshaft would stand up to the torque a motor would output, since the wankel wasn't particularly torquey.
If you're not already, keep a blog and pictures of the conversion - that would make for an interesting read!
> Eh, nobody bought that car for the fuel economy!
True enough, but I'm sure there are other factors in play, such as public policy. Fuel economy standards have been going up.
The motor I'm putting in my conversion is a Netgain Hyper9 (high-voltage, double-ended shaft version). It's about 120 horsepower and less than 200 foot pounds of torque, so in theory the clutch/transmission/driveshaft should be fine. (I'm keeping the 6-speed transmission.) It probably won't be particularly fast, but we'll see. More powerful AC motors exist, but they tend to be expensive.
I haven't posted any pictures yet; I've been meaning to, just haven't gotten around to it. There's another guy in the UK I think with a youtube channel that's doing close to the same thing, but with a Leaf motor.
On the other hand the quality and performance of those $80 catalytic converters are questionable at best. They have neither the longevity, nor the performance of the original part. They might last even 10 times less, and they're usually just barely good enough to pass the emissions tests, which is already the lowest bar to pass given how all manufacturers optimize for that. Real life emissions are far worse.
And the purpose of the catalytic converter is to make sure the CO, NOx, and unburned fuel are rapidly oxidized to CO2, N, and water before leaving the exhaust system. The outcome is that you will produce more greenhouse gases but fewer compounds that are more immediately dangerous to people, especially in cities. So it reduces localized pollution at the price of more CO2.
Catalytic converters don't reduce greenhouse gases. Their function is to reduce poisonous gases: NO, NO2, O3, CO, HO2, and sometimes HCN and H2CO. The good news is that all of these compounds are thermodynamically unstable so a catalyst can destroy them.
I don't know where you got the 14.7:1 number but I am certain that NOx are unstable at any concentration (at or near STP) and will always be depleted by a catalyst.
Another commenter is unsure whether the NOx or some GHGs should be reduced preferentially. To clarify: CO2 can't be removed, it is stable; only CH4, N2O and O3 can be removed, and they are not present at relevant levels (except ozone which is poisonous) anyway. The poisonous gases are far more important — NOx pollution alone kills thousands of people every year (statistically, considering excess deaths as correlated to air pollution).
The increased price of catalytic converters is partially related to the supply of palladium, which experienced a glut following the collapse of the USSR. The Soviet palladium ran out in 2012:
The cat has to be hot to catalyze. The engine is run rich so unburnt fuel makes it to the cat and is combusted there, warming it up enough to also kill the undesirable gases. This is wasted heat... unless you mount a turbocharger after the cat, which has its own set of weird tradeoffs. (I've never heard of a factory car with a rear turbo)
Tesla already uses aluminum for power cabling because it’s cheap and lighter weight. Tesla Model S were induction motors (at first at least) with no rare earths, and Tesla is partnering with CATL for lithium iron phosphate batteries in lower cost versions of, if I believe, Model 3 and Y.
I thought CATL makes lithium iron phosphate batteries, and lithium sulfur hasn't been commercialized yet. Unless there's some news on that front I missed?
I think induction motors tend to be less efficient than permanent magnet motors (and thus require more cooling). The Netgain Hyper9 (a popular motor for conversions) is a permanent magnet motor which doesn't use rare earths. It's very efficient but not particularly powerful (though that may be due more to the relatively low voltage it runs at).
That's cool that Tesla is using aluminum for power cables. Makes sense to save cost and weight where you can.
Yeah, aluminum is a worse conductor so you need thicker cable. It's less dense, though, so I think it usually comes out as being lighter. Thicker cables can be more inconvenient. I think aluminum also tends to have more problems with oxidation causing too much resistance at electrical contacts.
I think for motors generally you just end up with a larger motor for the same amount of power.
All points you make are very true. In addition, aluminum tends to crack as it ages and you'll find aluminum wiring is usually a culprit in electrical fires. In the world of mobile electronics, it's usually looked down upon as the cheapest alternative when compared to real copper conductor used in higher quality automotive wiring.
It only requires proper engineering of the connection. Aluminum itself doesn’t crack in properly engineered joints. What fails in old houses is shoddy connections.
If people look down upon it, it’s because they’re either lazy or ambivalent. It’s the superior performance solution in some situations.
cmon man. the total weight of pricey metals in a car is so low, there is no way its going to offset the cost of precision machining. tolerances < 1 thou and callouts for surface finish and perpendicularity are expensive!
Hard to say. Those tolerances would be expensive in general purpose machine work, but in engines those tolerances have been in place since at least the 1930s, and so economies of scale bring those costs down (ie, using specialized machines that are really good at boring precision holes and measuring them. The costs of those machines get amortized over every engine).
I'm sure a motor is cheaper than an engine (less steps to make), but they still require precision manufacturing, and all the other parts aside from the motor (driveshaft, axles, brakes, etc.) are more or less the same.
Plus, the cost of those other materials is going to increase if demand for EVs goes up.
Somehow car manufacturers are able to make engines, transmissions, transaxles, and differentials really cheaply, so apparently all that precision manufacturing doesn't really cost all that much when producing at high volume. This should be equally true of EVs and combustion-engine cars.
Raw material costs might still be less than the manufacturing costs, but they're pretty hard to avoid. Also, materials that are cheap now might not be if demand grows faster than supply.
> One thing I gained an appreciation for was how CHEAP cars and engines are. There's probably nothing else with as precise machining that is as inexpensive.
Not to denigrate the amount of engineering that went into car engines, but literally, what about chips? Devices that contain billions of transistors, arranged precisely on the order of nanometers. Yet they cost only hundreds of dollars.
They're apples and oranges. Chips are not machined, they're etched in batches. Their "tolerances", so to speak, are limited by the wavelengths of visible or UV light they use for creating the masks and exposing the photoresist that protects the wafer from hydrofluoric acid and other etchants. There's no mechanical force involved, except to spin wafers to apply coatings and move them between each stage of the process.
Engine blocks, on the other hand, are CNC machined one at a time and the force of machining steel causes vibrations that move the cutting tools thousands of nanometers back and forth. Placing both in the same building, for example, would likely cripple the semiconductor fab. Having a machine shop in China make a one off would likely cost as much as a luxury car.
Yes you are referring to another insanely complex thing that is very cheap relative to making one of cost due to mass production. But it isn't machined metal :) I didn't say I don't appreciate electronics too.
Still widely used and taught in the machine shops of highly reputable universities over here in the U.S.
If you're under 40 and can't use metric and imperial jargon without a second thought in the shop here that's a different problem. I personally enjoy doing machine shop-esque metal fabrication in metric and woodshop type things in imperial, but all machine shop instructors I've met through several good stem uni's that look even slightly middle aged love to talk in thou of inch, some to the point of getting quite physically frustrated when asked where the metric drill index/reamer set are in otherwise highly stocked shops...
Also, I've noticed and heard the same from others in surrounding states - Fluid Dynamics professors love to include absolutely unecessary boatloads of strange units and conversions in coursework/exams to apparently "prepare us for the shitshow that is industry"
I'm not denying the metric system. Just in the USA it is thou period. and if the measurement is a consistent unit of whatever it works. Also GM (and Holden in oz) are inch based. So using metric will subject you to mistakes possibly. I agree though in science SI is the way to go
Yeah I cut my teeth on Subaru engines (helped having a gf who was a subi then telsa mechanic walking me through it). Subi are all metric tho. My workshop is a mix of metric for new gear and imperial from my old mans days running a farm.
We even have some stuff thats neither metric or US imperial, but is british witworth imperial...so different again and just enough to make a difference. Makes for some confusing repairs when your working with stuff that's had a mix of all 3 systems due to a long life of repairs.
I was trained in Australia, in the past decade, and was taught thoroughly in both metric and imperial. The engineers and machinists I have worked with that insist metric is the only way habe been more prone to mistakes when imperial components pop up, as they do. Accuracy is down to the spec, the person and the machine, ease of use is identical when decimal inches are used, mistakes are a result of poor communication.
I just built an engine for my car. One thing I gained an appreciation for was how CHEAP cars and engines are. There's probably nothing else with as precise machining that is as inexpensive.
When cars started getting electronic engine controls, there was much internal grumbling about the cost. One Ford production guy, on hearing that the engine controller cost about $100, said "I can make the whole engine for 100 bucks."
Anyone who has the inclination to build an engine, should.
It is super rewarding not to mention you get to buy a bunch of really cool tools.
I build a 350 Windsor from the block. The research and design decisions were one of the best parts of the project. Then to put it all together and realize the power was amazing.
Ford (Aus) 4.0 was a great first build for me. I'm now taking my time on a Toyota 4K 1300cc, learning a lot more, and taking the time to design new components for it. Can't recommend it highly enough, though not for everyone to be sure.
Not only the tight measurements, but I've always been amazed at the precise timing of all the little moving parts, the valves all opening and closing at precise to-the-millisecond times so that each stroke happens, at 6000 RPM! So impressive. Especially with an interference engine, where getting that timing wrong means bent valves.
Mmm.. not really. It's just a cam and a spring. Pretty easy to get that bit working by yourself. Variable valve timing and lift is much more impressive.
Automatic transmissions also have hydraulic logic gates in the valve body (implemented with check-balls and piston servos), even if they're also electronically controlled. Drag-racers will reprogram the valve body to change the shift order, have launch control, etc.
The rest of the world figured that using prefixes with a predefined universal multiplier is more practical.
Therefore you can use the milifoot equal to a thousandth of a foot, or the kiloinch equal to one thousand inches, or the microyard equal to one millionth of a yard, maybe even the centifurlong equal to one hundredth of a furlong.
We are quiet proud of our prefixes. Now if only we would decide on a single reference unit to which to apply the prefixes. Conversion from megainch to hectofurlong is rather inconvenient.
>The distance between a crank bearing or rod bearing is less than 2 thousandths on modern engines. A small amount of oil in that tiny space is all that keeps your engine from having metal on metal seizure.
The BMW S65 and S85 engines are prime examples of what happens when the wrong tolerances are chosen. I can't think of another engine family where rod bearings are considered a maintenance item.
I built an LSX (Aftermarket GM) iron block engine (V8 LS) for a CTS V. I had to get some very precise tools (Have to measure to 10,000ths) or they were useless for bearing clearances and verifying cylinder diameters. My cylinders were 4.155 bore, and the bearing clearances were around 1.8 thousandths. Forged pistons, rods and crank.
I had cracked a cylinder/piston on the original LSA. I did not trust anyone to do the work so I did a lot of research and did it all myself. I appreciate someone asking because my friends and software dev co workers aren't interested :)
Yes you are right as far as LS engine builders there's loads. I could have ordered a crate engine from Texas Speed and been done with it. And yes for hours of my time spent vs hours of money saved I lost a ton of money. But all it takes is one very small mistake to make an engine short lived with these exacting tolerances. I'd rather blame myself than deal with someone kicking the blame back. It was also a personal satisfaction thing.
My wife's engine had an issue and it was the middle of winter so I said whatever let's just have a shop fix it. In the process they "flushed the transmission" and it failed 4 days after we got the car back. Of course they stonewalled us and I can't prove they broke it. So I ordered a late model wreck transmission and replaced it and 3 years later still running strong.
But I then decided that I would never be in that position again where someone could tell me it wasn't their problem and get me aggravated. With this engine I built it from raw parts. I had the block machined, and I had the tools to verify.
It was certainly not worth my time, but as you said I love working on cars too.
I have a buddy that is adamant about not flushing transmissions if you dont have a issue because he think its guaranteed to have an issue after, from his experience. lol
There is some truth to that, but not never. A flush will dislodge any metal shavings and crud from the moving parts. The filter should catch these, but the filters themselves can get clogged, and then bye-bye transmission.
Flushing can really be bad if you've never done a routine flush on a schedule. You don't want to go 150,000 miles before your first one. You would need a garage with a forced flush system to move it all out, and then probably flush again soon after to make sure all the gunk is out.
Transmission oil breaks down with heat and wear like any other, and will eventually contain sludge and dirt.
I'd concur with that. Note this was one of the notorious to fail JATCO nissan/mitsubishi transmissions. Blowing fluid through with pressure makes no sense. Sediment sitting in pans does not affect operation until it is agitated into suspension
The Nissan automatics and especially manuals(cd009) are fairly strong. It's their CVT that's the issues. I don't know why Nissan insist on using them with their V6's.
>I had cracked a cylinder/piston on the original LSA. I did not trust anyone to do the work so I did a lot of research and did it all myself
I love working on cars so I totally get wanting to do that, but why didn't you trust someone else to do the work? There are probably more reputable LS builders across the US than any other engine family.
It sounds like he wanted some very precise work done. Quality in the blue collar trades has gone to nil in the last decade. And if you do find someone that is very detailed and "by the book" level of quality, you are going to pay 3X the normal labor rate. For instance, this is a performance transmission shop [0] that regularly takes apart "precision" rebuilt transmissions only to find they were not done right at all.
LS engines are among the most common engines in custom built cars, and there are countless shops out there who specialize in them. No offense to him or you, but it's quite ridiculous to believe you can do a better job building an engine on your first try than shops like Texas Speed who have been doing it for decades with full blown R&D labs and regularly build 2000+ horsepower motors, all with highly skilled machinists and engineers using professional equipment that the average person would never be able to afford.
I could do a better job than them in all due respect. I care about my job more than anyone on earth. I know they do good work but if we could both measure to the same specs and know we did it right, how could I do it worse than them. we have the same measuring tools. Not that I think they do bad work. But if you ever built an engine you know its all about attention to detail. there is nothing they have to verify the integrity of the build that I don't to a similar level of precision.
Edit: I dont have the machines they do, but when my bare block comes back from the machine shop, my tools are just as good as theirs to verify the dimensions are correct. That isn't possible to verify with a built short or long block. They could possibly have 100 employees that care as much about my job as me who knows. This is a job about verification of specs and assembling correctly not of insane tech. They don't have anything I dont when assembling an engine. Machine work yes
It helps that they are abundant (in the hundreds of millions units produced), have been in use for decades (since the mid-50s), and are simple to work on (as evidence by the OP randomly learning to machine one).
As cool as 2-atom thick plasma transfer wire arc cylinder liners are, that's not something which will ever be available to a layman.
I really doubt the OP did the machine work himself, those tools are not affordable for just using once or twice. Buying bore gages and mics however is totally doable.
And no, the LS motors have been in use since '97. Including the gen1/2 small blocks doesn't count, there are no shared parts between them.
17-18 thou here on my LS6 on the rods. 23-24 on the mains. I'd like to see tighter on the mains, but not sure if its worth ordering another set of bearings and using 1/2 of them to tighten up 1/2 a thou like i did on the rods.
what amazes me is the cam lifts we're running these days. I'm running .646"/.649". In the 90s .500" was big for a street motor, and only full blown race motors were running whats normal now.
Damn, dropping a new engine in a CTS V? What year? NA? How much power are you shooting for? The CTS V is definitely one of my favorite cars, I'd love to own one one day, but the ones with the manual trans hold their value pretty well :)
Huh? What do you mean "takes off". Do you mean do we build LS motors now instead of gen1/2 SBCs then yes.
If you mean "do the LSx heads drop onto a gen1/2 SBC", then no, not at all. only thing common between them is the cylinder spacing. The LS uses 4 bolts per cylinder like a ford, instead of 5 like the SBC, the firing order is different, the valve layout is different (ports are symmetric vs mirrored), etc.
Mostly what i've seen is making the SBC take a symmetrical head. Saw some INSANE CFE pro stock heads at the machinist last year, he was building them in a large bore, short stroke deal setup for bonneville to run like 11krpm.
Why did you go iron block for your build? Is it that your were afraid you cracked the block again?
How did you do that in the first place. Are you running any boost on this engine?
I'm running 14 lbs boost yes. And yes it was piece of mind that it's much harder to crack and unlike the aluminum block I can bore it more than 5-10 thou if it needed it again. Downside is 100lbs more but this is in a 4200lb car so whatever
Any race or high power engine, especially those that rev quite high will need rebuild - not just in bottom end but often with piston rings and valves as well.
You don't really hear about those other engines much because their buyers understand that a race engine needs more maintenance than any other road car.
Also, not beating on the engine until oil has warmed up to temp will elongate the bearing lifespan quite a bit. I have a friend with E60 6mt S85 that has factory bearings at 110k mi and has perfect oil analysis results.
The S65 and S85 are road car engines, not racecar engines. They're also hardly BMW's highest performing motors. Even Dinan built engines don't suffer from that problem.
They're meant to be dual duty. There aren't any road car engines I'm aware of that use individual throttle bodies or 12+ compression without direct injection.
The S54 engine which came before the S65/85, was also high revving, had 11.5:1 compression ratio and didn't have any of the rod bearing issues. The 20v Toyota 4AGE also had them too with a high compression ratio.
The S54 absolutely had rod bearing issues. There was a recall on the 2001-2003.5 M3s to replace them and BMW switched to 60w oil as part of the remediation. They’re still having issues to this day.
The S54 is also notorious for VANOS issues and cam drive failures. I had to replace the solenoid pack on mine but elected to not upgrade the drive while I was in there.
> Also, not beating on the engine until oil has warmed up to temp will elongate the bearing lifespan quite a bit.
I am curious if there is proof to this. I've always felt the same way. I know in the "old days" with iron pistons, if you you simply started up a cold motor and and drove it hard without a warm up period, the pistons would expand quicker than the block and would start to scour the walls and/or lock up.
But other than that, the only other "proof" I have is from people in high school that like clock work at 3:30 everyday, would smoke tires leaving the parking lot everyday. They seemed to go through motors every 6 months. I'm talking knocking bearings and lifters cracked in half. I've never gotten rough with anything I own until after a 20 minute "warm up" and all has been well (so far).
In my experience with these, when I've heard the first indicator to do it, the damage is done. Standard regular maintenance hasn't identified the issue in advance. I'd be curious to see whether long term monitoring of particulates in oil can make an help though.
I’m starting to think it may just be minimizing cost. Theoretically that just means “maximize profit”, but I suspect in practice it means a whole slew of bad behavior and design choices. I.e. Pay for the part that’s .0001 cent cheaper than another option, despite the cheaper part possibly being a fire hazard.
I've always felt cars were like computers; most people (me included) pay a premium for something mediocre because they don't want to bother understanding it.
My personal solution is to live near the metro and bike as much as possible.
Mediocre in what way? Buy almost any new car from a well known brand today and it will run for 200,000+ miles. You almost need to deliberately buy a mediocre car. Biking and taking the metro is better for the environment, your health, and your budget though. If you are fortunate enough to have that option.
>So one would think that when EVs reach the same scale they will be significantly cheaper than ICE vehicles.
I expect that batteries are the only hangup, there's probably not that much magic left in an electric motor. Additional cost for regen brakes of course.
I agree on the amazing cheapness of it all if you stick with the common stuff. That, along with the low cost of flat panel TVs is a miracle of the modern age.
Regen braking has no physical cost associated - it's pure software/firmware. The exact same hardware that is used to power the car forwards can be used for regen braking. It can be as simple as a single negative sign in the code to cause the phase to be 180 degrees out, current to flow backwards, torque to go the other way, and the battery to be charged instead of discharged.
One day regen braking will take over hydraulic brakes, and another big cost/complexity of a car will be eliminated. The only reason that doesn't happen today is there are lots of laws and regulations requiring hydraulic brakes, and braking systems typically require more redundancy than power systems.
> Regen braking has no physical cost associated - it's pure software/firmware.
I think this is a slight exaggeration.
The way I understand regenerative braking is that you (effectively) run your AC generator in reverse of what you would in order to accelerate in the direction of motion and then take the current generated by that, rectify it to DC, and use that current to charge a battery. The energy in the system is provided by the back EMF induced in the stator by the magnetic field generated by the motor rotor. I agree that the AC generator is going to stay the same, but I think there's specialized hardware needed for the rectification and charging cycles. At the minimum, you need a more specialized battery and battery management system to make sure that you're balancing the charge across the cells in your battery.
I think you are overestimating unique requirements of typical car engines. They are usually DC powered AC engines, where the DC->AC converter (generating 3-phase AC of controlled power and frequency) can probably run backwards (AC->DC) with at most a few minimal hardware changes, if any.
If you're not overdoing regen, you probably don't need additional balancing. Even if you wanted to charge the EV by towing, you could probably use the normal charge balancing circuitry, again minimal if any HW changes. Non-wimpy batteries and cells should be fine - if they can fast-charge, they can take regen. Might have some limitations on acceptable power vs. temperature, charge state etc.
> One day regen braking will take over hydraulic brakes, and another big cost/complexity of a car will be eliminated.
I have read somewhere that the regenerative braking is much less effective when the car is going really slow, so you still need the hydraulic brakes to come to a complete stop.
True, but you can also use a tiny bit of battery power to do "reverse acceleration" to do the final stopping.
It is true that electric braking would continuously use a small amount of power to stay stopped on a slope. That wouldn't be an issue for a few hours, but you couldn't park on a hill for months without ending up with a flat battery, and then eventually the car rolling away.
Small locking pins are the answer to this, rather like the "park" on automatic gearboxes. They are very cheap, since they don't need to do any actual stopping, but merely keeping something stopped.
Is that right? I didn't know that. I'd like to see a BOM on a regen braking as compared to a simple disk brake system.
One implication to software-only brakes is that it requires that that corner is a drive wheel. If that's the case, I suppose that anti-lock is simply firmware and a sensor.
note: I do see that Teslas have master cylinders, so they apparently are hydraulic braking systems.
A bill of materials? As OP said, there is literally nothing required aside from what is required to make the car go forward. An electric motor is a generator.
Teslas have traditional braking systems in addition to the regen braking. The hydraulic brakes have nothing to do with the regen system.
I appreciate that now. Thank you to everyone for the education.
>The hydraulic brakes have nothing to do with the regen system.
I strongly suspect that they interact for antilock.
I wonder how Teslas deal with parking brakes, historically kind of an issue with disks.
It does seem to me that an entirely regenerative braking system would imply additional expense in terms of the strength of the half shafts, u-joints, transmission if any.
Parking brakes for disc brakes are usually in the center of the disc rotor (like a mini drum) with shoes. Some others like Chryslers have implemented hybrid brake cylinders
That's really astounding, I just looked at a 55 inch brand name 4k TV going for 400 bucks retail.
Guess it's the same logic as cramming more CPU, etc. into the usual couple hundred sq. mm chip. But you get more CPU for the same money and chip size, which is not as spectacular as more screen size for less money ...
> there's probably not that much magic left in an electric motor.
I believe this sentence has been said about many technologies in the past that definitely invalidated it. I'm more playing devil's advocate than trying to falsify you, likely for being burned sometimes reading or, worse, stating it, haha.
There isn't much more efficiency to be gained in the electric motor world. Motors typically get 90% of theoretical efficiency, so any improvements there will be modest.
Substantial improvements in other metrics might be had, but they probably won't massively impact EV's (weight and costs of the motor are both a small part of the total for a car)
Batteries are a huge hangup. For example, we don't know how to recycle them and they aren't good for dumps. And, used car batteries are expensive to replace and you get a lot fewer miles per charge out of older cars. Manufacturing of cars isn't great for the environment so we should want older cars to last. This model helps push people to more new cars faster.
Engine cylinders are honed to accuracies that are less than 1 thousandth of an inch. Crank journals as well and rod journals. This is all precise machine work with metal. I use inches here because in machine work thousandths of inches is the language du jour. Transmissions are similar works of very precise and clean machine work.
The distance between a crank bearing or rod bearing is less than 2 thousandths on modern engines. A small amount of oil in that tiny space is all that keeps your engine from having metal on metal seizure.
So one would think that when EVs reach the same scale they will be significantly cheaper than ICE vehicles.