Comment by specialp
5 years ago
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.
[0] https://imgur.com/a/7X0sPlk
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.
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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:
https://www.mining.com/russias-stockpiles-said-to-be-deplete...
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The reason is the increasing price of Palladium which is used by catalytic converters and your dentist. That's why there is huge increase in theft of those converters as the material is scraped and sold in the black market.
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.
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Note to replace copper wiring with aluminum, you have to go up at least one gauge size.
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"Tesla already uses aluminum for power cabling because it’s cheap and lighter weight."
Ugh, really ? That offends my sensibilities ...
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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.
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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.
> "I use inches here because in machine work thousandths of inches is the language du jour."
Yeah not in Australia unless your machinist is >50 years old. Metric is more accurate/easier/less prone to mistakes. Metric is what we use.
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'm in Europe, and I've had/worked on German, Japanese and Swedish cars and boat engines. Metric all the way.
Only time I've needed an imperial set of tools was when overhauling a B&S lawnmower engine.
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.
I think automatic transmissions are more impressive looking than engines when they're open. They resemble EV motors too!
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.
VW group has a dual-clutch automatic transmission that includes an EV motor for their plug-in hybrids, the DQ400E. It looks pretty cool indeed!
> I use inches here because in machine work thousandths of inches is the language du jour.
Only in the USA ;)
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.
Nice! What engine did you build?
>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.
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>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.
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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 :)
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Very cool. Although I own an LS, I've never touched an LS. The Sloppy Mechanics guy is impressive though.
Since a short block is mostly just a short block, I'll be interested in seeing if LS heads/intake manifold/headers takes off in the SBC community.
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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?
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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.
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> 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).
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Subaru EJ motors munch through rod bearings quite happily.
What are the indicators that replacing them is neigh?
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I thought once you replaced the crappy OEM bearings you were all set on these engines. I guess it is not the case?
> I use inches here because in machine work thousandths of inches is the language du jour.
I'll make a wild guess: In the USA.
EDIT: Heh, sorry... See https://news.ycombinator.com/item?id=26991690 . This time I really thought I'd checked, but there was lots of catalyst talk in between.
If people were willing to pay the higher cost for the same feature set, why would they well them for cheaper? Why not pocket the extra profit?
I don't like this line of thinking but I'm sure it's going to or already is happening.
...
Because the whole nature of market competition? People will still choose the cheaper option if its available.
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.
competition, a bedrock element of fair markets, capitalism, and efficient economic allocation, something we seem to have collectively lost sight of.
How about your phone.
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.
> Additional cost for regen brakes of course.
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.
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> 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.
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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.
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> the low cost of flat panel TVs is a miracle
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)
> I expect that batteries are the only hangup,
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.
No problemo. Just go to a big honkin' flywheel somewhere under the back seat.
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