Comments by "Mikko Rantalainen" (@MikkoRantalainen) on "driving 4 answers" channel.

21:15 Finally you mention the need for one way clutches! I think these are the real killer for this design. All one way clutches I know of allow only choosing 2 from the following: - low wear rate - minimal backslash - high torque It seems that this design would need all three at the same time! Other than that, superb design and this video explains the mechanism pretty well.
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13:02 There's one benefit for using rubber gasket instead of metal gasket: the rubber gasket is cheaper for the manufacturer. It's worse for the owner of said engine but if the owners doesn't understand what they are purchasing, manufacturers will continue keep introducing this kind of cheaper to produce parts in the future, too.
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@karlisbanis2442 The lifetime of the valvetime solenoids is also totally unknown. I would assume the the lifetime problems is the cause for the delays.
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@Old_BMWs Wouldn't brake mechanism require friction surfaces and cause lots of wear and power loss?
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@HungrySharkMaster See the mechanism of this thing. The small gears that pull the center one at a time must freewheel in one direction and not rotate into another. This mechanism will not work at all without using one way clutch for each of these small gears. Yes, this limitation would be less problematic for a bicycle. But make no mistake, it's there not because it would be just nice to have, it's there because this mechanism will not work otherwise.
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@GeorgeWashingtonLaserMusket Yes, when you consider how many parts a single freevalve solenoid has inside, it's far from simple solution. Basically one solenoid is replacing one segment of valve lift cam and the valve spring. That's total of 2 parts. If (/when!) freevalve solenoid has more than 2 parts, the probability of failure goes up, not down. As a result, the solenoid requires higher manufacturing quality to result in similar lifespan. That doesn't exactly sound like the cheap solution, which is probably why it hasn't taken off. In theory, freevalve is a great product still.
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Great video! I didn't know about offset and you explained it so clearly I had zero trouble following everything.
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I think the most important upgrade for Yaris GR is better suspension than the stock. If you're interested only straight line acceleration, it makes more sense to get some Tesla instead of trying to tease out more power out of this engine.
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VW TDI engines use both MAF and MAP sensors and their measurements must match or the ECU will cut down the power. They can only detect leaks in turbo boost pipes if both sensors work correctly because in that case MAF sensor will show all the air going to turbo but MAP sensor will see some of the air missing. Broken EGR valve can also mess the manifold pressure which is measured by MAP sensor.
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@chocolatethunder3218 Good points! I sure hope freevalve tech will get into ICE cars because full transition to EV will take quite some time still. It seems that the old video is all we have about the freevalve and I would guess it's still too expensive to use even though it has all the advantages explained in this video: https://youtu.be/S3cFfM3r510
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@alphaforce6998 Typical cylinder head with full valve mechanism is far from insignificant friction – try rotating the cam with bare hands... That said, I agree that air compressors are even harder to turn by hand. However, it's much easier to route air channels than to transfer mechanical movement so you could e.g. integrate the air compressor to the crankshaft reducing the need for any additional bearing surfaces.
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10:00 The most important part of this video!
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Wet timing belt rationale in nutshell: it reduces fuel usage 1% and if you only run on highways with zero stop and go traffic or short trips, it will last for the whole warranty period. Once warranty period has expired, the original manufacturer no longer cares at all. And the warranty period is short enough to prevent the issue from appearing even with stop and go traffic.
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15:30 Rubber is very interesting material because if you press is too hard, it will lose some of its friction because of shearing. That's the reason why using narrower tires is not better for all cases. Basically you could drive fastest by using the narrowest possible tires that do not year shear. That's why street sports cars using insanely wide tires are more looks than purpose.
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@szymoniak75 Could you point to some research that claims otherwise?
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Great video! I would also argue that if you do any drifting that surely means that you're not interested in tyre wear at all.
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Koenigsegg style Freevalve is the ultimate implementation of this technology. I think it could at least in theory only adjust the intake cycle length to adjust the engine power and run the gasoline engine at full throttle at all times similar to diesel engine.
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Timo Mäkinen drove about 13 km at OuninPohja, Finland in 1967. Here's funny video (in Finnish, but English subtitles behind the CC button): https://youtu.be/6uXXM36C5Jg?t=298
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Interesting design but I think the biggest problem with this design is the fact that you now have effectively two sets of camshaft bearings and one set is on moving element. Considering that camshaft bearing is already absolutely critical for high power applications even with traditional designs, trying to extract even more power from this design is going to be hard for the lubrication.
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Plastic is used everywhere in the engine bay these days, not because it's better but because it's cheaper. As the cars still cost the same or even more than in the old days, that means high profit margins for the manufacturer. After all, if the plastic lasts the warranty period, its failure is no longer the manufacturer's problem. The whole issue is caused by poorly educated car buyers that are mostly interested in shape of the headlights and shape of the door windows, because that's the only thing they understand at all.
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So for optimal performance, you would need some kind of setup that can adjust the exhaust system dimension based on RPM. Easier said than done when the exhaust gasses are so hot that you have to use steel or it will melt. In addition, the exhaust gases contain lots of carbon which has tendency to get into all sliding parts and jam them after longer exposure.
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The whole video should have had "this is not scientifically correct terminology or explanation" but otherwise it's good. The explanation of tire contacts twisting demonstrated by hands on the floor was clever.
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It was quite jarring to me too, but it definitely makes me remember this video and this engine.
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