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Internal Combustion Engine

ciechanow.ski

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Re: Internal Combustion Engine

#41

Post by specialp »

tmh88j wrote: post #32
specialp wrote: post #15

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 in…

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 maint…

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 :)

Re: Internal Combustion Engine

#42

Post by dahfizz »

Viker wrote: post #25
larsnystrom wrote: post #23

In a few decades the internal combustion engine will be to transportation what the typewriter is to typing today. It’s kind of mind boggling, but there is really no alternative if we want to stop increasing the CO2 concentration in our atmosphere.

Hmm... Hard to beat that energy density when the workload is large. Trucks, tractors, planes, ships. Sure consumer cars will be EV but ICEs are not going anywhere

This sparked my curiosity...

Currently gasoline has about 50x more energy per unit weight than a tesla battery pack.

Battery energy densities have tripled in the past 10 years. Keeping on that pace, it would take over 30 years for batteries to be competitive with gas.

When you account for the astoundingly bad efficiency of ICE, though, the gap in usable energy decreases. This is why a tesla can go 300+ miles with a battery that can only store the same energy as 2.4 gallons of gas.

Re: Internal Combustion Engine

#43

Post by kirse »

tmh88j wrote: post #32
specialp wrote: post #15

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 in…

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 maint…

Subaru EJ motors munch through rod bearings quite happily.

Re: Internal Combustion Engine

#44

Post by towndrunk »

kingsuper20 wrote: post #10

It's a lot scarier when you see things going under load at speed. Lots of wiggling, twisty magic, waves. Smokey Yunick (blessed be his name) used to make see-through timing covers, oil pans, valve covers + strobe light + some sort of oscilloscope setup to watch the craziness. I think I remember seeing the results for small block Chevrolet timing gears on sprint car engines as the teeth wiggled more and more with rpm.…

You can get clear valve covers for some BMW motorcycles now. https://www.youtube.com/watch?v=BE71lpgJ4ng

Re: Internal Combustion Engine

#45

Post by londons_explore »

kingsuper20 wrote: post #31
specialp wrote: post #15

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 in…

>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.

Re: Internal Combustion Engine

#46

Post by mfer »

kingsuper20 wrote: post #31
specialp wrote: post #15

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 in…

>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.

> 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.

Re: Internal Combustion Engine

#47

Post by elihu »

specialp wrote: post #15

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 in…

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.

Re: Internal Combustion Engine

#48

Post by clairity »

mfer wrote: post #38
specialp wrote: post #15

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 in…

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.

competition, a bedrock element of fair markets, capitalism, and efficient economic allocation, something we seem to have collectively lost sight of.

Re: Internal Combustion Engine

#49

Post by admax88q »

mfer wrote: post #38
specialp wrote: post #15

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 in…

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.

Re: Internal Combustion Engine

#50

Post by csours »

If the author is reading this: A great addition would be common breakdown reasons, perhaps on another page.

Something I didn't really think about until recently: solid metal bearings are used on the crank and piston journals as they can handle more force than ball or roller bearings. In other areas, ball and roller bearings are used to minimize energy loss.

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