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Fully digital valves open up engine possibilities

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Re: Fully digital valves open up engine possibilities

#41

Post by SmellyGeekBoy »

inferiorhuman wrote: post #32
tomatotomato37 wrote: post #3

I thought koenigsegg was already doing this with their freevalve thing Also I saw an interesting point in an article about the koenigsegg thing that would pertain to this too; environmental laws would be much harder to practically enforce with this as you could run virtually any engine anemic enough to get though the emissions tests (and set it as the default mode to get around the Volkswagen nonsense) and then offer…

> environmental laws would be much harder to practically enforce with this as you could run virtually any engine anemic enough to get though the emissions tests lol Changing a cam (or cams) in most engines isn't all that difficult. Even without a camshaft you'll still be heavily limited by the shape and size of the combustion chamber and the geometry of the valves. You simply won't be neutering the engine that much.

Changing a camshaft in a classic car is huge pain that requires specialist equipment for setting the timing etc. and getting it wrong can destroy the engine. It's more than possible in a home setting but most home mechanics I know wouldn't touch them. I'm sure it's a lot more complicated on a modern car.

Re: Fully digital valves open up engine possibilities

#42

Post by kwhitefoot »

You don't necessarily need such valves to make engines easier to start. I remember my father-in-law's Lister diesel generator, from over forty years ago, that would start automatically when you turned on a light or appliance. It had a tiny starter motor and also a starting handle in case the battery was flat. There was a switch or valve that you would turn manually, or if the battery was not flat automatically, that made it possible to turn the motor. It was pretty much impossible to turn the engine over manually without doing that; with it, it was easy.

I'm not a mechanical engineer and I have no idea how it worked beyond knowing that it reduced the degree of compression.

Re: Fully digital valves open up engine possibilities

#43

Post by parimm »

They have replaced a pure mechanical linkage with a motor in each valve.

A typical 4 cylinder engine will now need sixteen extra motors to run it.

While I like the idea of controlling the timing of each valve interdependently for the other, I am not for the additional electronics in the engine.

Re: Fully digital valves open up engine possibilities

#44

Post by parimm »

kwhitefoot wrote: post #42

You don't necessarily need such valves to make engines easier to start. I remember my father-in-law's Lister diesel generator, from over forty years ago, that would start automatically when you turned on a light or appliance. It had a tiny starter motor and also a starting handle in case the battery was flat. There was a switch or valve that you would turn manually, or if the battery was not flat automatically, that…

Its called a decompression valve.

Re: Fully digital valves open up engine possibilities

#46

Post by jaclaz »

ebikelaw wrote: post #30

This article is pretty much wall-to-wall snake oil. The bit at the end is just completely false. Some people, who hadn't really bothered to do the math at the time, believed fifty years ago that spring-closed valves would float at high speeds and desmodromic valves were the solution. But that isn't true: metallurgy marches on, and nobody has been seriously impeded in making an engine turn at any desired speed with va…

>Motorcycle engines turn at stupefying speeds without experiencing valve float. In practice it's actually the desmodromic designs that are troublesome, because of all that moving mass.

Sure, go tell Ducati.

Re: Fully digital valves open up engine possibilities

#47

Post by Pulcinella »

tibbon wrote: post #34
TheSpiceIsLife wrote: post #23

Earlier quoted context omitted.

> environmental laws would be much harder to practically enforce ... and then offer high/sport/cruise modes that runs the engine at full capacity otherwise Only if your company is ready to willfully break the law. The vehicle ought to, at the time of testing, meet or exceed all relevant standards, and not have a user accessible option to circumvent the standards.

Well there’s a car hacking then for a future Defcon tuning panel then... because if I buy it, I want to be able to hack and modify it in any way I want. As long as I’m not violating emissions, then it should be within the law Thankfully, automakers have quite and uphill battle to actually make something secure and inaccessible, so I feel confident a solution would be found :)

This does happen now in car culture where people will tune it “chip[1]” their car to increase performance. In practice, it’s difficult enough (you can’t just do it through the car’s infotainment system) that your average driver won’t do it and it’s probably not to big of an empact on the environment[2] and people’s health[3].

[1]”Chipping” used to enclose physically replacing a car’s ECU but now it usually just means the control software has been chnaged digitally. [2]Unfortunately, some awful people will and do “roll coal” to purposefully increase emissions and smoke. It’s illegal in many places but difficult to enforce.

[3]Your car still has to pass emissions and sometimes people do bring the ECU back to stock firmware before annual inspections just to pass. Difficult to enforce but tuning usually sacrifices fuel economy for performance and its not simple to do. Most people who just want a grocery-getter won’t be trying it.

Re: Fully digital valves open up engine possibilities

#48

Post by rcxdude »

hevi_jos wrote: post #15
ak217 wrote: post #11

Earlier quoted context omitted.

> The simplicity advantage of electric will soon take a quantum leap when driveshaft-free 4 motor all wheel drive vehicles hit the market You can't just eliminate the driveshaft because the wheel must be on a suspension. Remove the driveshaft and you have to put the motor on the wheel, increasing unsprung weight, exposing the motor and making high voltage parts subject to damage. 4 motors is more complex than 2 and d…

4 electric motors on wheels is extremely simpler than 2 motors, mechanical differentials and couplings. I actually helped a mechanical engineer to create a simulator for car dynamics in software. Today's cars are over engineered mechanically in order to support and resist the forces and torques from the motor to the wheels. When you put the motors in wheel you basically reduce the required rigidity and the weight of…

Also, while it's simpler, it's not really much cheaper (which is the big driver of a lot of automotive decisions). Motors and power electronics are far more expensive than the mechanical components which you are removing (and this is not easy to change, though there is more headroom for economies of scale on the EV motors ATM).

Re: Fully digital valves open up engine possibilities

#49

Post by ebikelaw »

jaclaz wrote: post #46
ebikelaw wrote: post #30

This article is pretty much wall-to-wall snake oil. The bit at the end is just completely false. Some people, who hadn't really bothered to do the math at the time, believed fifty years ago that spring-closed valves would float at high speeds and desmodromic valves were the solution. But that isn't true: metallurgy marches on, and nobody has been seriously impeded in making an engine turn at any desired speed with va…

>Motorcycle engines turn at stupefying speeds without experiencing valve float. In practice it's actually the desmodromic designs that are troublesome, because of all that moving mass. Sure, go tell Ducati.

Tell them what? That literally every other major manufacturer makes a motor with higher max engine speeds, higher reliability, and lower maintenance costs? Or that in the 60-year history of Grand Prix motorcycle racing they've only won once?

Re: Fully digital valves open up engine possibilities

#50

Post by HeyLaughingBoy »

inferiorhuman wrote: post #33
yontherubicon wrote: post #21

Earlier quoted context omitted.

Sure, but emissions testing after you've got the car would be utterly useless.

How so? Roadside emissions testing is very much a thing, as are annual emissions checks.

Not in all states. I haven't had to do it in 20 years.
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