A new Continuously Variable Valve Actuation system

[Anonymous]

At www.pattakon.com a new Continuously Variable Valve Actuation system is presented, with working prototype photos, plots and animations (even stereoscopic ones).
Any engine, racing or normal, can be improved as the torque can be about constant from very low revs to the top allowable revs of the engine.

Comments? Objections?

 

[Anonymous]

Well it definetly looks more promising than the Hot Rocker system.
http://www.hotrocker.com/index.html

I think if I were him, I would be entering into some endurance rally events and get a little buzz going about the system. That will get the venture capital coming in.

John

 

[Anonymous]

It does actually appear to work...interesting! 8)

 

[FloridaRustang]

The simplicity of it is so beautiful. I had been working on my own similar ideas but couldn't overcome certain geometry issues. He folded the whole thing in on itself. Given bit of time, figuring out the math and angles on his system would not be all that hard.

And I've experienced Athens traffic. If his system holds up there, it'll be fine most everywhere. Most impressive is his daily use of this system.

Now, Floridaphatman, can you pour iron as well as aluminum?

 

[Anonymous]

Sorry Bro,

I need about a six man crew to run a cupola furnace.
About how many pounds of cast iron are we talking about. If its a small amount, under 20 pounds, then yes I can.

Send me a PM, lets talk about it.

John

 

[xctasy]

Johns main job....Francis Ford cupola director. A good joke, no? :roll: :roll: :roll: :roll: :roll: :roll: :arrow: :duh: :nono:

 

[Straight Six]

At www.pattakon.com a new Continuously Variable Valve Actuation system is presented, with working prototype photos, plots and animations (even stereoscopic ones).
Any engine, racing or normal, can be improved as the torque can be about constant from very low revs to the top allowable revs of the engine.

Comments? Objections?

How would this work on a 200 ci with c4 tranny?

 

[Leddemo]

Hmm.. was waiting to post untill I actually owned a 250... oh well

http://www.pattakon.com/vva/SideCam.htm

This seems the easiest solution to that. Very similar (and personally I think less complex). These things are really neat... I can't stop watching them.

 

[Anonymous]

I will be glad to answer your questions about Pattakon VVA.

By the way, take a look at the unconventional (still very close to conventional technology) Pulling Rod Engine or PRE at http://www.pattakon.com/pre/index.html .

Thanks
Manolis Pattakos

 

[Straight Six]

Ok - sorry but I understand some of whats being said on the site but my mechanicle apptitude/understanding isnt as high as Id like --someone explain this engine tech in laymans terms-please

 

[Leddemo]

The system changes the duration and the lift of the valves. A short duration camshaft will yeild more torque, a camshaft with alot of duration will yeild lots more horespower. usually one has to find a balance of the 2. But with the system, it can change how long the valve stays open and change-on-the-fly to a different profile.

for low engine speeds it limits the amount of time the valves are open (and how much they open), giving great torque and fuel economy, when the RPM's get higher, it adjusts so the valves open farther and stay open longer, allowing the engine to breathe and achieve very high hoersepower. Normally you have to choose between a very high torque, low RPM camshaft (lower horsepower in higher RPM's). Or a high RPM, high horsepower camshaft (not as much low RPM torque). It gives the best of both worlds. But not just like a camshaft in between, but the extreme ends of each camshaft choises. Super low RPM torque, and Super high horsepower.

this also keeps the torque and horsepuower curves really flat, and maintains a higher, brauder (sp?) level of torque and horsepower throuought the RPM range of the engine.

I think that might help, I hope I explained everything right.

 

[Anonymous]

Leddemo,
If you replace the term ‘valve duration; with the term ‘valve lift’ in your explanation, then you are right.

In a few words, in the cylinder head of the Pattakon VVA civiv prototype there are two wild camshafts (12 mm valve lift, 300+ degrees duration and extreme overlap as in racing engines), having four cam lobes each (i.e. one cam lobe per pair of valves). Below the camshaft there is a control shaft which is rotated by the gas cable (the deeper you press the gas pedal the more the control shafts is displaced angularly, and when the gas pedal is released, the control shaft restores to each ‘idle’ angular position).
When the gas pedal is completely pressed, the intake valves open for 12 mm, the duration is long and the overlap is extreme (at TDC the intake valves are open for 2.7 mm and the exhaust valves are open for 1.9 mm), so the engine is like a racing engine.
With medium press of the gas pedal, the valve lift is medium and the ‘actual overlap’ is medium.
And when the gas pedal is only slightly pressed, the engine operates with valves lift even less than 1mm and with zero actual overlap, i.e. it operates more smoothly than any smooth family car. When the Honda prototype is driven into Athens traffic, it rarely needs more than 2mm intake valve lift.
From the 12mm valve lift to the 0mm valve lift there are infinite modes of operation, directly selected by drivers right foot. That simple. The throttle valve is gone and the intake plenum is cut forming an ITB of the minimum possible air flow resistance (with zero cost).

Download the
http://www.pattakon.com/vvar/VTECtoVVA/VVArOperation2D.exe animation and open it. Pressing the Space Bar on the keyboard, the valve lift is changed (there are shown only three steps to keep the size of the animation small).

Download the http://www.pattakon.com/vvar/OnBoard/Assembly.exe photo collection and open it. Then press D or d key on keyboard to see a few, of the infinite available, curves of Valve lift versus crankshaft.

Also download and read the
http://www.pattakon.com/vva/LiftTiming.htm. It explains the differences of conventional and VVA engines.


Thanks
Manolis Pattakos[/img]

 

[addo]

Corrections have been added, Mr P.

We had to remove the edit feature because people would sometimes get upset and delete what they had posted, rendering damage to technical issues discussed.

Regards, Adam.

 

[Leddemo]

I rewatched the Fourlifts.exe file and rewatched it, I guess I just missed it. It doesn't change the duation, just lift.

If the vales lift were controlled by the drivers foot on a wild duration camshaft, if you really put your foot into the accellerator at lower RPMs wouldn't it negate any advantages?

So does this system also act as the throttle body as well?

 

[Leddemo]

*edit^ Found it.

 

[Anonymous]

Leddemo,

Suppose you drive the car at constant speed having 2000 rpm and partially compressed gas pedal for 1.5 cm using the 3/4 of the maximum torque the engine can provide at 2000 rpm (i.e. you work at partial load). If you press a little more the gas pedal, let say to 2 cm, the engine provides its maximum possible torque at 2000 rpm (i.e. now you use the 4/4 of the maximum possible torque at these revs) and the car accelerates. If you press a little more the gas pedal, nothing changes. But if you press deeper and deeper the gas pedal, the engine's behavior approaches the behavior of the conventional racing engine with the wild camshafts. So, in the worst case you take the conventional's behavior.
The way to protect the new driver from doing this is simple: A movable, by an electromotor, stop can be used, activated by the rpm of the engine. At 2000 rpm this stop prevents the control shaft from rotating more than the rotation angle that provides the maximum torque at these revs. At 4000 rpm the stop is displaced in order to alow the gas pedal to be pressed from zero to a maximum where the engine provides its maximum possible torque at 4000 rpm, and so on, In real world this stop was never used. The driver feels the engine output, so he needs not stop.
Do not confuse the operation of such a "stop" with the 1KW electromotors placed between drivers right foot and "control shaft" used in BMW's valvetronic. In Pattakon the drivers' foot directly controls the rotation of the valve lift profile (can you imagine more direct control?). The "stop" (if used) does not need accuracy and its only work is to displace a pin/stopper that prevents the control shaft from more than necessary angular displacement.
Read the "A general View" at www.pattakon.com web site. It explains the previous and more.
Also read the "Variable Valve Timing" topic. It explains how much this "constant duration VVA" affects the timing of the engine. To be more clear: most camshafts developers refer to the duration of a camshaft as the degrees from the crankshaft angle the valve is opens for 1.0 mm to the crankshaft angle the valve lift is decreased to 1.0 mm. If you agree in such a definition, Pattakon VVA changes a lot the duration. So, don't think about duration and overlap as just degrees. It is more than that. It is degrees AND lift. Thing the following case: you have a racing engine having extreme overlap, let say 90 degrees overlap with the intake valves open 4 mm at TDC and the exhaust valves open 3 mm at TDC. Think now the VVA having the same 90 degrees angular overlap with the intake valve open 0.4 mm at TDC and the exhaust valve open 0.3 mm at TDC. The actual overlap of Pattakon VVA is 1/10 of the conventional. Do read the "Variable Valve Timing" topic.

You are right, the intake valves act as the trottle of the engine. The air before the intake valves is always at atmospheric pressure.

Thanks
Manolis Pattakos

 

[Leddemo]

I was kinda late when I read it the first time through, still not sure how I managed to miss all of that. It makes much more sence to me now that I know it's always running WOT, and to keep the RPMs lower just don't dump on the throttle.. well.. gas pedal, untill higher RPMs.. I get how it all works now.

 

[Straight Six]

So how would this work on a 200 ci 6?straight bolt on? remove the log?carb,other equipement???power/fuel economy specs fr the 200 ci 6??Just trying to understand how it affect our 6's

 

[xctasy]

Straight Six, this topic doesn't directly relate to our I6's just at the moment.

As you may be aware, in the Hardcore session, people just bring in stuff, and talk about it, technically. A show and tell with all the bells and whistles and doo dads. That means some of it is likely to be over our heads, and lots of technical stuff gets discussed.

From what I've heard since 1985, variable valve technology is still in its infancy. Generally, all new mechanical concepts take about 20 years to get funding, and another 20 years to become acceptable to a production line. This idea might be fast tracked into production for fitting to earlier cars, but I doubt it will surface on our I6's. If it eliminates needing a camshaft and is compact, it could work.

The key here is that when owners of cars change camshft timing and the ammount of lift at the valve, they do it by getting an aftermarket camshaft, which incorporates about 100 years of developement.

Any camshaft has been designed to work on one specific engine. The system above allows any desirable lift and cam timing, and is much more complicated...about as far as a Mountain bike is from a Penny Farthing!

 

[jamyers]

REALLY interesting idea, I'd love to see it on my Buick 455 V8!

OK, I understand the system changes the valve lift and duration, which affects the overlap, intake closing, etc. To put this on any engine, you'd have to install a pretty wild camshaft (and valvesprings) to begin with, and then the system 'tames' the cam down to match the rpm/load?

What I'm not seeing is how you can take the throttle plates out of a carburetor and have it meter at idle speeds, since carbs draw through a separate and smaller idle circuit at really low flow rates. How is that managed?