An advanced 'VTEC'

[manolis]

Hello.
At http://www.pattakon.com/vvar/HelpRoll.htm you can see another version of our variable valve actuation system (this time with rollers).
The system is so close to Honda’s VTEC (in S2000, CivicTypeR etc) and at the same time it is so different in operation, you will be stunned.
Just take a look.
Thank you
Manolis Pattakos

[350HP930]

From what I see in your documentation all your system accomplishes is changing valve lift.

If that is what you think VTEC and VarioCam is doing you are mistaken.

These technologies either run multiple cam profiles or change cam timing.

The general rule of valve lift is that it needs to be maximized under all conditions so I think your solution is not doing anything worthwhile.

If your solution could change cam timing or the profile used then I would say that you are onto something.

[beepbeep]

350HP: nope, early VTEC changes lift only...also, newest 996TT runs low valve-lift up to certain RPM (to maximize swirl & torque and minimize polution) and then shifts to high-lift lobes.

[350HP930]

I dunno where you get that idea about VTEC. I have been familiar with VTEC since the early 80s when honda was developing it for motorcycle applications and it switches the valves over to an entirely different cam profile, not just a change of total lift.

VarioCam only alters cam timing while VarioCam Plus combines cam timing and an alternate profile system like VTEC.

I stand on my statement that a system that alters only valve lift is useless.

[911pcars]

"I stand on my statement that a system that alters only valve lift is useless."

That's a pretty broad statement to make. Sure, a system that actively changes both lift and duration is going to be a better solution, but to say add'l lift is not going to help engine performance is not being totally accurate.

I couldn't see the animated drawing on my system so I can't add my two cents, but the theory is correct. If the execution can be done within reason, I'd give it a go.

Sherwood Lee
http://members.rennlist.org/911pcars

[manolis]

Originally posted by 350HP930
From what I see in your documentation all your system accomplishes is ... cam timing or the profile used then I would say that you are onto something.

Hello.
Please take a look at http://www.pattakon.com/vva/LiftTiming.htm page of the site to understand how effectively the new system manages the timing and the overlap of the engine.
The only two (or three) different cam lobe profiles used in VTEC of Honda make all the difference. The new VVA actually provides infinite cam lobes for intake, and infinite cam lobes for exhaust valves, and you can use every moment the best combination of them.
A different profile offers different lift, different duration and different overlap. The new system keeps the extreme duration, necessary for high revs and high power output, and changes dramatically the lift and the overlap (not the angular overlap but the actual one). Note that the overlap is not just some crankshaft degrees.
If the actual overlap seems a strange quantity, just think the following example:
A room has two windows in its two sides. If you keep both of them widely opened for a second, you have a specific overlap, that is ability of sweeping the room with air coming from one window and trying to leave from the other. If you need less overlap, you can decrease the time both windows are opened, as all present VVT systems do. But you can also decrease the ‘how widely’ the two windows are opened, like the new VVA does.
The new VVA offers actually an overlap, which is about linearly proportional to the revs and linearly proportional to the load. At low revs and partial loads it is many times lower than the overlap the mild come lobes of Honda VTEC offer, and at high revs and full load it can be significantly larger than the overlap the wild cam lobes of Honda VTEC offer. So the new VVA does control the overlap.
Just read the page mentioned.
Thanks
Manolis Pattakos

[manolis]

Originally posted by 911pcars
"I stand on my statement that a system that alters only valve lift is useless."

That's a pretty broad statement to make. Sure, a system that actively changes both lift and duration is going to be a better solution, but to say add'l lift is not going to help engine performance is not being totally accurate.

I couldn't see the animated drawing on my system so I can't add my two cents, but the theory is correct. If the execution can be done within reason, I'd give it a go.

Sherwood Lee
http://members.rennlist.org/911pcars

Hello
Try the page
http://www.pattakon.com/vvar/index.html
and select the animation you like.
Please inform if you can download the animations
Thank you.
Manolis Pattakos