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Internal Combustion Engine

ciechanow.ski

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Re: Internal Combustion Engine

#11

Post by bob1029 »

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.…

Reciprocating machines are fairly remarkable when you consider all of the components involved, forces, etc. Even more so when you think about how long a typical car engine lasts.

These incredible forces are why rotary and turbine engines are substantially more reliable. Some gas turbines have only 1 moving part, and in some applications this moving part experiences zero wear due to magnetic/aerodynamic/active bearings.

Re: Internal Combustion Engine

#15

Post by specialp »

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.

Re: Internal Combustion Engine

#17

Post by bitexploder »

bob1029 wrote: post #11
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.…

Reciprocating machines are fairly remarkable when you consider all of the components involved, forces, etc. Even more so when you think about how long a typical car engine lasts. These incredible forces are why rotary and turbine engines are substantially more reliable. Some gas turbines have only 1 moving part, and in some applications this moving part experiences zero wear due to magnetic/aerodynamic/active bearing…

[*] more reliable in theory. Mazda RX8 and rotary engines are famous for being a bit maintenance heavy and unreliable.

The amount of engineering and brain power that has gone into making common ICE engines in cars in wide deployment reliable is staggering.

Re: Internal Combustion Engine

#18

Post by [deleted] »

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…

[deleted]

Re: Internal Combustion Engine

#19

Post by bob1029 »

bitexploder wrote: post #17
bob1029 wrote: post #11

Earlier quoted context omitted.

Reciprocating machines are fairly remarkable when you consider all of the components involved, forces, etc. Even more so when you think about how long a typical car engine lasts. These incredible forces are why rotary and turbine engines are substantially more reliable. Some gas turbines have only 1 moving part, and in some applications this moving part experiences zero wear due to magnetic/aerodynamic/active bearing…

[*] more reliable in theory. Mazda RX8 and rotary engines are famous for being a bit maintenance heavy and unreliable. The amount of engineering and brain power that has gone into making common ICE engines in cars in wide deployment reliable is staggering.

Agreed on automotive rotary. It's not in the same spirit as the gas turbine and others.
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