In a past life I worked on a rocket engine turbopump that spun at 160,000 RPM. It’s crazy to visualize how fast that is. The stresses in the metal are so high that we needed speciality alloys made exclusively for us. The parts are literally ripping themselves apart.
High speed turbo machinery is certainly an odd area -- like you said, its on the verge of ripping itself apart. The Leybold turbo molecular vacuum pump on my bench at home is rated to spin at 60,000 RPM. In the old days of metal fabrication you'd have two specialty precision machines to locate, drill and bore holes -- the jig bore and jig grinder. Once you bored a hole, if the part was heat treated there was almost certainly a need to touch up the bore from slight deformation so a jig grinder, a jig bore base with a 100,000+ RPM pneumatic grinder, is used to perform the final precision machining.
What diameter was the part that spun at that speed? Also do you have some idea of the maximum forces exerted on it? It might not be much higher (as in, less than on order of magnitude) than the peak forces exerted on some parts of a reciprocating engine. And the turbine doesn't have to constantly switch between tension and compression, which I think should help a lot when designing a part that moves quickly.
I don't think it's overly pedantic or even really pedantic at all as there's only one reason for any author to make such assumptions knowing full well that it won't hold for the entire audience. (The reason being editorializing the title to make it sound more appealing than it might otherwise be)
What's wrong with "9000 RPM is faster than my screen refreshes" or "9000 RPM is faster than most screen refreshes" or "9000 RPM is faster than an average screen refreshes"?
"Shocking" news that is anything but. "Little known facts" that are widely known. "Mistakes your making with ..." that you've never once made. It's all just trying to get you to consume the content.
But even with 244 Hz the engine running at 9000 rpm or 150 Hz will not even give you two frames per revolution, about 221° of rotation per frame to be precise. If you want a somewhat smooth animation, say 10° per frame, you want to look for a 5400 Hz monitor.
Yup, 240Hz here make even idling look more like something glitching than moving fast.
At 1/4th the speed idling moves fine, but the individual pixels don't have time to reset properly and some artifacts can be appreciated (1ms refresh time 27" IPS panel)
Once you go above 144 hz, the returns really start to diminish.
Going from 60 to 144 hz in games was great. Certainly noticeable. Going from 144 to 240, it's much more subtle. I'm not sure I'd even notice 500 versus 240 unless I had them side-by-side.
I just tried it and it does that thing where because it makes nearly, and then more than, one revolution per frame, the pistons and crankshaft appear to slow down and stop, then go in the other direction.
Well.. as so many things in engineering: it’s a tradeoff. Mechanically, it’s also very important to let the engine warm up and cool down before and after heavy load. Primary reasons for warmup are that the oil is more fluid on higher temperatures and metal is also less fragile when 50 or so degrees above freezing. Cooldown is especially important on turbo engines as the turbo on hundreds of thousands revs per minute and high temperature needs oil to be pumped through the bearings. If you turn it off after heavy load on engines that do not keep the oil running after motor shutdown, there is a chance that oil burns and gets stuck in the bearings, degrading performance or worst case breaking the turbo.
Also for the warmup case, tolerances inside the engine are designed assuming a hot engine. At lower temperatures, the metal hasn’t expanded yet causing also more stress on various parts such as the piston (seals).
And for the turbo I forget to mention that if you leave a turbo engine idle for a few minutes that this allows both the temperature and speed of the turbo to reduce. Many trucks have a sticker in the dashboard saying “do idle engine x minutes before shutdown to avoid turbo damage”. (And also not for extended periods which I’m not 100% what’s the reason but I guess it’s due to diesel engines possibly getting too cold while idling.)
The externalized consequences of drivetrains failing faster (or being abandoned because they give the perception they might) easily offsets whatever gains are achieved with this nanny tech.
Auto start/stop is a great example of weirdly aggressive nerds failing to explore nuance, which is found everywhere.
In the early days it also killed starter motors as they weren't rated for that duty cycle.
I feel these kinds tech are more symbolic than functional and exist to simply check off boxes to obtain environmental ratings. I would even guess the environmental ratings are also short sighted and exist as symbolic gestures of environmentalism. Basically, environmentalism performance theater.
At idle, it doesn't take that much fuel to keep the engine alive. Idle stops are more important for noise abatement and local toxic exhaust gas emissions - a lot of exhaust gas treatment depends on the exhaust gas having a minimum amount of thermal energy.
The downsides of idle stops are, however, that they tend to put a lot of load on the engine, especially from the lack of oil pressure at the very few first strokes [1], and that the low temperature deposits all kinds of gunk in the exhaust pipework instead of transporting it outwards.
If you run an engine with idle stop, it really really is important to properly take care of the engine, including preventative maintenance and regular oil changes.
[1] That is even more of an issue in large engine blocks, hence that high pitched noise you hear from ships and locomotives for a while before they start up - that is an ancilliary oil pump, priming the entire oil pipework until all air is gone and full oil pressure is present at all ports in the system.
Yeah I disable idle stop on my cars, for exactly those reasons. If I'm going to be stopped for more than a minute or two, I'll let the engine idle so that temperatures can normalize, then shut it off manually.
Back when turbochargers became common on passenger cars, there was even advice to be sure you let the engine idle for a minute or two before shutting it off, so that the turbocharger could cool. Otherwise the oil in the turbocharger would get baked into a goo. Modern synthetic oils, and turbochargers, handle this better today but I still like to give any hot spots a chance to cool off.
> The downsides of idle stops are, however, that they tend to put a lot of load on the engine
While I don't doubt that it seems like this is essentially a solved issue. Priuses are some of the most reliable, long-lasting cars out there despite experiencing considerably more start-stop cycles than a traditional ICE with start-stop would.
A Prius isn't taking off from a stop under strictly ICE power. The electric motor in the transmission lowers the load on the ICE, certainly enough to let the engine oil pump generate operating pressure before it's really under load.
Up to 2022 the Prius' ICE barely had 70 kW of engine power, and (IIRC, take with a grain of salt) neither turbochargers nor compressors. The less capacity the engine has, the more abuse it can tolerate, and it likely was ridiculously overspecced in tolerances and thicknesses.
In contrast, your 100 kW+ average vehicle? Probably built for maximum profit margins.
In a past life I worked on a rocket engine turbopump that spun at 160,000 RPM. It’s crazy to visualize how fast that is. The stresses in the metal are so high that we needed speciality alloys made exclusively for us. The parts are literally ripping themselves apart.
Turbos you find in cars like the Civic operate between 180000 - 200000 RPM. But working at a rocket engine manufacture is more interesting.
High speed turbo machinery is certainly an odd area -- like you said, its on the verge of ripping itself apart. The Leybold turbo molecular vacuum pump on my bench at home is rated to spin at 60,000 RPM. In the old days of metal fabrication you'd have two specialty precision machines to locate, drill and bore holes -- the jig bore and jig grinder. Once you bored a hole, if the part was heat treated there was almost certainly a need to touch up the bore from slight deformation so a jig grinder, a jig bore base with a 100,000+ RPM pneumatic grinder, is used to perform the final precision machining.
What diameter was the part that spun at that speed? Also do you have some idea of the maximum forces exerted on it? It might not be much higher (as in, less than on order of magnitude) than the peak forces exerted on some parts of a reciprocating engine. And the turbine doesn't have to constantly switch between tension and compression, which I think should help a lot when designing a part that moves quickly.
Also there's a honda that revs to 20k RPM - https://www.youtube.com/watch?v=2FOGOUkxcTQ
It is awe-inspiring to think about the metal internals of a combustion engine moving so quickly because they're so heavy and complicated.
But in some ways it's more impressive to think about a $40 Dremel 4000 that can plug into a 120v electrical socket and spin at 35000 RPM
I'm being incredibly pedantic, but 244Hz monitors would refresh faster than the revolutions, right? Or do I misunderstand Hz
I don't think it's overly pedantic or even really pedantic at all as there's only one reason for any author to make such assumptions knowing full well that it won't hold for the entire audience. (The reason being editorializing the title to make it sound more appealing than it might otherwise be)
What's wrong with "9000 RPM is faster than my screen refreshes" or "9000 RPM is faster than most screen refreshes" or "9000 RPM is faster than an average screen refreshes"?
"Shocking" news that is anything but. "Little known facts" that are widely known. "Mistakes your making with ..." that you've never once made. It's all just trying to get you to consume the content.
But even with 244 Hz the engine running at 9000 rpm or 150 Hz will not even give you two frames per revolution, about 221° of rotation per frame to be precise. If you want a somewhat smooth animation, say 10° per frame, you want to look for a 5400 Hz monitor.
Yup, 240Hz here make even idling look more like something glitching than moving fast.
At 1/4th the speed idling moves fine, but the individual pixels don't have time to reset properly and some artifacts can be appreciated (1ms refresh time 27" IPS panel)
Your monitor refreshes a bit faster than my motorcycle. '09 Yamaha FZ6 14k redline, 240hz would be about 14,400 rpm.
I thought exactly the same, as an owner of a '09 FZ6 as well, high five
But combustion engines go also much faster than 9000 RPM; afaik bike engines can reach 18000 RPM or more.
Not pedantic enough because we have 500Hz monitors already. Don’t think that’s the point the author was trying to make though.
Once you go above 144 hz, the returns really start to diminish.
Going from 60 to 144 hz in games was great. Certainly noticeable. Going from 144 to 240, it's much more subtle. I'm not sure I'd even notice 500 versus 240 unless I had them side-by-side.
You’re correct, would be equivalent to 150Hz. I was curious too since my monitor is 360Hz :)
I just tried it and it does that thing where because it makes nearly, and then more than, one revolution per frame, the pistons and crankshaft appear to slow down and stop, then go in the other direction.
i like going to https://makermotor.com/rpm-visualizer/ and bumping up the rate to multiples of my refresh rate and seeing the pattern change.
No wonder idle stop is so important.
Idling at 900rpm or 15cycles per second is a tremendous waste. Somehow I always assumed it was slower.
0.9k RPM is way too fast to be the low end of a machine.
Well.. as so many things in engineering: it’s a tradeoff. Mechanically, it’s also very important to let the engine warm up and cool down before and after heavy load. Primary reasons for warmup are that the oil is more fluid on higher temperatures and metal is also less fragile when 50 or so degrees above freezing. Cooldown is especially important on turbo engines as the turbo on hundreds of thousands revs per minute and high temperature needs oil to be pumped through the bearings. If you turn it off after heavy load on engines that do not keep the oil running after motor shutdown, there is a chance that oil burns and gets stuck in the bearings, degrading performance or worst case breaking the turbo.
Also for the warmup case, tolerances inside the engine are designed assuming a hot engine. At lower temperatures, the metal hasn’t expanded yet causing also more stress on various parts such as the piston (seals).
And for the turbo I forget to mention that if you leave a turbo engine idle for a few minutes that this allows both the temperature and speed of the turbo to reduce. Many trucks have a sticker in the dashboard saying “do idle engine x minutes before shutdown to avoid turbo damage”. (And also not for extended periods which I’m not 100% what’s the reason but I guess it’s due to diesel engines possibly getting too cold while idling.)
True, idling is wasteful, but at the same time “spinning fast” does not necessarily equate to “high energy consumption.”
The CPU fans in my computer spin at about 1000 RPM all day long but that doesn’t mean they’re consuming a lot of electricity.
Idle stop == cam death rattle.
The externalized consequences of drivetrains failing faster (or being abandoned because they give the perception they might) easily offsets whatever gains are achieved with this nanny tech.
Auto start/stop is a great example of weirdly aggressive nerds failing to explore nuance, which is found everywhere.
In the early days it also killed starter motors as they weren't rated for that duty cycle.
I feel these kinds tech are more symbolic than functional and exist to simply check off boxes to obtain environmental ratings. I would even guess the environmental ratings are also short sighted and exist as symbolic gestures of environmentalism. Basically, environmentalism performance theater.
> easily offsets whatever gains are achieved with this nanny tech
That's a matter of opinion, which may not be shared by anyone living near places that have seen decreases in noise and air pollution due to idle stop.
At idle, it doesn't take that much fuel to keep the engine alive. Idle stops are more important for noise abatement and local toxic exhaust gas emissions - a lot of exhaust gas treatment depends on the exhaust gas having a minimum amount of thermal energy.
The downsides of idle stops are, however, that they tend to put a lot of load on the engine, especially from the lack of oil pressure at the very few first strokes [1], and that the low temperature deposits all kinds of gunk in the exhaust pipework instead of transporting it outwards.
If you run an engine with idle stop, it really really is important to properly take care of the engine, including preventative maintenance and regular oil changes.
[1] That is even more of an issue in large engine blocks, hence that high pitched noise you hear from ships and locomotives for a while before they start up - that is an ancilliary oil pump, priming the entire oil pipework until all air is gone and full oil pressure is present at all ports in the system.
Yeah I disable idle stop on my cars, for exactly those reasons. If I'm going to be stopped for more than a minute or two, I'll let the engine idle so that temperatures can normalize, then shut it off manually.
Back when turbochargers became common on passenger cars, there was even advice to be sure you let the engine idle for a minute or two before shutting it off, so that the turbocharger could cool. Otherwise the oil in the turbocharger would get baked into a goo. Modern synthetic oils, and turbochargers, handle this better today but I still like to give any hot spots a chance to cool off.
> The downsides of idle stops are, however, that they tend to put a lot of load on the engine
While I don't doubt that it seems like this is essentially a solved issue. Priuses are some of the most reliable, long-lasting cars out there despite experiencing considerably more start-stop cycles than a traditional ICE with start-stop would.
A Prius isn't taking off from a stop under strictly ICE power. The electric motor in the transmission lowers the load on the ICE, certainly enough to let the engine oil pump generate operating pressure before it's really under load.
Up to 2022 the Prius' ICE barely had 70 kW of engine power, and (IIRC, take with a grain of salt) neither turbochargers nor compressors. The less capacity the engine has, the more abuse it can tolerate, and it likely was ridiculously overspecced in tolerances and thicknesses.
In contrast, your 100 kW+ average vehicle? Probably built for maximum profit margins.
Unless you have a hybrid vehicle, like the Prius. Which basically switches to electric during idle stops and barely has any downside.