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Registered:
July 2003
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Re: New stepless throttless valvetrain
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Fri, 04 July 2003 04:15
 
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[quote title=oldcorollas wrote on Thu, 03 July 2003 15:05 ... replacing conventional rocker arms with something similar to this?
Cya, Stewart
[/quote]
Hello from Greece.
Do not compare the diameter of two push rods to see which one can carry heavier load. Your pushrods is "weaker" than the small pushrods of the prototype just because they are many times longer, thing that make them easier in bending.
I hope you mean wear of 0.05 to 0.1 mm and not 0.5 to 1 mm.
Normally, even the 0.05 mm wear is excessive.
The valve actuators/adjusters (the small cylinder on the top of the valve stem) and the small push rods are so small, cheap and simple pieces that they will be replaced when necessary. They are like the replaceable shims of conventional engines.
The control of the valve lift is done by the rotation of the control shafts. As the accelerator pedal is pressed, a string (the previous “throttle string” or “throttle wire”) is pulled and the control shafts are rotated. When you leave the accelerator pedal, the control shafts return in their idling position immediately, just by the action of the normal valve springs. This is all. The accelerator pedal is heavier, of course. But the response is so direct you cannot believe.
In the prototype the brake pedal is also heavier as there is no vacuum in intake manifold to amplify the force applied by driver’s foot on brake pedal.
Always there is the option of “drive by wire”.
Or you could use some kind of “servo” (electric, hydraulic etc) to lower the necessary force on the accelerator and brake pedals.
And of course the prototype had to be as Spartan as possible.
As regards the OHV designs, the proper position of the VVA system is between camshaft and pushrods, if there is room there.
But the more parts and joints between cam lobe and valve stem, the worse the total accuracy.
So it seems easier and more effective the application of the system in OHC engines and even better in DOHC, 4 valve per cylinder engines.
Thanks
Manolis Pattakos
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| | Subject | Poster | Date |
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New stepless throttless valvetrain
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manolis | Tue, 01 July 2003 04:06 |
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Re: New stepless throttless valvetrain
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ae86drift | Tue, 01 July 2003 06:16 |
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Re: New stepless throttless valvetrain
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oldcorollas | Tue, 01 July 2003 08:30 |
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Re: New stepless throttless valvetrain
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manolis | Wed, 02 July 2003 09:33 |
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Re: New stepless throttless valvetrain
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oldcorollas | Thu, 03 July 2003 05:05 |
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Re: New stepless throttless valvetrain
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manolis | Fri, 04 July 2003 04:15 |
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Re: New stepless throttless valvetrain
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mrshin | Thu, 03 July 2003 10:16 |
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Re: New stepless throttless valvetrain
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manolis | Fri, 04 July 2003 07:32 |
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Re: New stepless throttless valvetrain
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SupraPete | Fri, 04 July 2003 03:18 |
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Re: New stepless throttless valvetrain
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manolis | Fri, 04 July 2003 07:35 |
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Re: New stepless throttless valvetrain
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SupraPete | Fri, 04 July 2003 04:28 |
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Re: New stepless throttless valvetrain
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manolis | Fri, 04 July 2003 07:49 |
