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Discussion Starter · #1 ·
I was wondering the other day when we will see some sort of shaft driven valve train instead of chains or belts. :idea:
 

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Space, weight, and simplicity come to mind. I will grant you that it is a good idea in a sense, because a basic ring and pinion setup would work fine.
 

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I've always thought that this

seems like a good idea. No more camshafts, lifters, push rods, rocker arms, valve guides, springs etc.

Last I read about it the problem was poor efficiency at high RPM, due do the air mass having to rotate as it goes through the intake valve.

Another idea I had :idea: (though probably not the first) was why not have electric solenoid operated valves? Solid state electronics are nearly bulletproof today, and no moving parts except for the valve/solenoid itself means much more reliability, also it would also have the advantage of a much simper way to achieve variable valve timing, with much greater variations possible from current mechanical or hydro variable valve timing systems.
 

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Sags said:
Another idea I had :idea: (though probably not the first) was why not have electric solenoid operated valves? Solid state electronics are nearly bulletproof today, and no moving parts except for the valve/solenoid itself means much more reliability, also it would also have the advantage of a much simper way to achieve variable valve timing, with much greater variations possible from current mechanical or hydro variable valve timing systems.
Only possible issue that comes to mind would be lubrication, and heat. Electronics and heat don't mix well, so when combustion occurs I'd imagine failure of the solenoids would be swift. But engineers would probably find a way around this. As far as the topic of lubrication I guess sealing everything up should prevent this.

The concept sound great, though! Maybe one day we'll see something of this sort.

-Robert
 

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TKEPA251 said:
Sags said:
Another idea I had :idea: (though probably not the first) was why not have electric solenoid operated valves? Solid state electronics are nearly bulletproof today, and no moving parts except for the valve/solenoid itself means much more reliability, also it would also have the advantage of a much simper way to achieve variable valve timing, with much greater variations possible from current mechanical or hydro variable valve timing systems.
Only possible issue that comes to mind would be lubrication, and heat. Electronics and heat don't mix well, so when combustion occurs I'd imagine failure of the solenoids would be swift. But engineers would probably find a way around this. As far as the topic of lubrication I guess sealing everything up should prevent this.

The concept sound great, though! Maybe one day we'll see something of this sort.

-Robert
fuel injectors do it all day long. same idea, just a little different application. couldn't be too hard to make it work.
 

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Pooch said:
fuel injectors do it all day long. same idea, just a little different application. couldn't be too hard to make it work.
I guess you're right, but like I said some good engineering would make this possible.

-Robert
 

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Discussion Starter · #7 ·
Seems to me, electric solenoids large enough to open and close valves would be quite noisy. Think injectors clicking times 100.
 

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Electronic valves were thought of 30 years ago lol. They were tested for F1 use, but never got far because of electronic imitations of the time. Then the Iris valve came along and F1 said bye bye to regular valves.

The hard part isn't having the idea, its making it work and making it stick.
 

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ImpulseRocket89 said:
Electronic valves were thought of 30 years ago lol. They were tested for F1 use, but never got far because of electronic imitations of the time. Then the Iris valve came along and F1 said bye bye to regular valves.

The hard part isn't having the idea, its making it work and making it stick.
And that takes $$$! We won't see it in a domestic auto maker ever probably just for that reason. Japan will have it developed years before anybody else, more than likely.

-Robert
 

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Sags said:
I've always thought that this

seems like a good idea. No more camshafts, lifters, push rods, rocker arms, valve guides, springs etc.

Last I read about it the problem was poor efficiency at high RPM, due do the air mass having to rotate as it goes through the intake valve.

Another idea I had :idea: (though probably not the first) was why not have electric solenoid operated valves? Solid state electronics are nearly bulletproof today, and no moving parts except for the valve/solenoid itself means much more reliability, also it would also have the advantage of a much simper way to achieve variable valve timing, with much greater variations possible from current mechanical or hydro variable valve timing systems.
The auto industry has been playing with that for years. The thing is,how far do you need to advance or retard timing. The thing is,there is a limit to how far you need to do it,which makes systems that can advance and retard timing with respect to some zero point a better solution than just having independent valves. There are plenty of ways to do that although Im not really familiar with how any of them specifically are implemented.

Electronic systems are certainly possible. On an interference engine it would be dangerous though,you blow a fuse and the engine is gone.
If I were designing a variable valve timing system,I would use a variable torque magnetic clutch. There would be a spring that holds the sprocket into the maximally advanced position. The magnetic clutch would apply a braking torque to the cam,which would cause the cam to lag and the timing to retard. More torque,more retard,controlled by a servo loop with a cam angle sensor. There would be a stops on the sprocket to prevent the timing from being advanced or retarded to the point where the valves interfered with the pistons. You could open and close valves with any reasonable timing and any reasonable duration. I expect in fact that if you look at actual systems you will see similarities,although I think they run off hydraulic pressure.

Of course,its not QUITE that simple. You have rotating mass interacting with a bunch of springs and masses undergoing linear motion. You have to have a good model of how all that works together. You use that to understand how you need to adjust the torque on the clutch. The system does not react instantly,so you need to know what WILL happen and how fast it will accelerate when you change the parameters. You need to not only know the constants involved in the model,you need to have an idea of what constants you cannot know,because they change as the engine ages,and you have to allow the computer to measure those values so that it can continue working properly.
 
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