A-vtec

[owequitit]

Here is an article discussing the submission of patent applications for Honda's new VTEC system.

Discuss.

http://www.vtec.net/news/news-item?news_item_id=659664

[NAiL05]

Yea I heard about this. Advanced VTEC ftw!!! haha. Honda is going off with there VTEC systems lately. Quickest transition from I-VTEC - A-VTEC. I thought they would keep the i-Vtec like the old VTEC setup for quite a while then swap out but damn the quickness. Its all G though Honda always is moving forward with this technology =D.

[kmart64]

I didn't really get half of it cause I only skimmed...but I do like the part about the camshaft being more advanced so that even MORE torque+hp is assessible

[lil_dcb7]

you hear that? A-VTEC just kicked in, y0

[Punkrampant]

A dual stage vtec. Lets see what hasport does with that.

[head4life]

http://www.pattakon.com/

That guy is from Greek his version of vtec was almost like the new a-vtec.

He had said something about a patent IDK

[gloryaccordy]

http://www.pattakon.com/

That guy is from Greek his version of vtec was almost like the new a-vtec.

He had said something about a patent IDK

Ahhh you fucker...I was about to post that link...

Back in my engineering school days I fooled around with the idea of a valvetrain with a variable rocker pivot...of course mine were huge, ugly, clumsy and inherently flawed. But I was lead to Pattakon's site during a search for something in existence. I think Pattakon actually already had a patent long ago, and was just looking for a manufacturer to buy it...perhaps Honda took the plunge?

Honda's system is wildly simple though.


Piece #10 is anchored on the same axis as the camshaft. The cam acts on piece 10, which is anchored at point 20. When piece 10 is to the left, the cam pushes on piece 10, which pushes on piece 22 and acts on the valve. It being on the left though retards the cam action and minimizes the mechanical advantage the cam has on the valve, giving it zero lift. As piece 10 swings to the right, this mechanical advantage increases to maximum value and gives the valve maximum lift, and advance in action. If I had any video making skills I would put something together. Basically, again, the pivot through which the whole thing acts on is moved to vary lift...to the left puts the pivot in the line of action through which the rocker moves, minimizing lift...to the right moves it away, maximizing it.

Pattakon's system is somewhat similar in purpose, as it too has infinitely variable lift, but it doesn't affect timing. Basically, what Pattakon does is rather than change the lever arm, he changes the direction the cam acts through to vary maximum lift. I.e., at max lift, the cam pushes directly on the rocker arm, whereas at minimum lift it kind of grazes it. With a cam gear Pattakon's system looks to be a lot simpler to make and more practical. Not to mention, he already has 2 running prototypes...one of which is a B16 equipped Civic Ferio.

I'm still at a loss as to how BMW's Valvetronic works, but I imagine it's a variation of Honda's AVTEC system, albeit more crude and complex as it isn't conducive to high revving. In any case, with these systems in place, modders will have it made, as they will be able to run as wild of a cam as they want on their street car, and still pass smog and all that good stuff. It will be easier to tune for as it won't require a change-over point on the cam, and it should be able to rev as high as a regular motor, because there is only one extra moving part. I'm sure the only thing keeping Honda from putting it out is making sure all the parts don't shake themselves out of alignment down the line, as well as creating some kind of training program for mechanics to diagnose problems and work on this new valvetrain.

All in all though it looks pretty neat, and again, seems to be the be-all end-all of cam-based valvetrains. This will make the K20 look like the A20. I can't wait!

[owequitit]

Ahhh you fucker...I was about to post that link...

Back in my engineering school days I fooled around with the idea of a valvetrain with a variable rocker pivot...of course mine were huge, ugly, clumsy and inherently flawed. But I was lead to Pattakon's site during a search for something in existence. I think Pattakon actually already had a patent long ago, and was just looking for a manufacturer to buy it...perhaps Honda took the plunge?

Honda's system is wildly simple though.


Piece #10 is anchored on the same axis as the camshaft. The cam acts on piece 10, which is anchored at point 20. When piece 10 is to the left, the cam pushes on piece 10, which pushes on piece 22 and acts on the valve. It being on the left though retards the cam action and minimizes the mechanical advantage the cam has on the valve, giving it zero lift. As piece 10 swings to the right, this mechanical advantage increases to maximum value and gives the valve maximum lift, and advance in action. If I had any video making skills I would put something together. Basically, again, the pivot through which the whole thing acts on is moved to vary lift...to the left puts the pivot in the line of action through which the rocker moves, minimizing lift...to the right moves it away, maximizing it.

Pattakon's system is somewhat similar in purpose, as it too has infinitely variable lift, but it doesn't affect timing. Basically, what Pattakon does is rather than change the lever arm, he changes the direction the cam acts through to vary maximum lift. I.e., at max lift, the cam pushes directly on the rocker arm, whereas at minimum lift it kind of grazes it. With a cam gear Pattakon's system looks to be a lot simpler to make and more practical. Not to mention, he already has 2 running prototypes...one of which is a B16 equipped Civic Ferio.

I'm still at a loss as to how BMW's Valvetronic works, but I imagine it's a variation of Honda's AVTEC system, albeit more crude and complex as it isn't conducive to high revving. In any case, with these systems in place, modders will have it made, as they will be able to run as wild of a cam as they want on their street car, and still pass smog and all that good stuff. It will be easier to tune for as it won't require a change-over point on the cam, and it should be able to rev as high as a regular motor, because there is only one extra moving part. I'm sure the only thing keeping Honda from putting it out is making sure all the parts don't shake themselves out of alignment down the line, as well as creating some kind of training program for mechanics to diagnose problems and work on this new valvetrain.

All in all though it looks pretty neat, and again, seems to be the be-all end-all of cam-based valvetrains. This will make the K20 look like the A20. I can't wait!

LOL! I wondered where you had been.

It is definitely simpler than BMW's system, and actually appears to incorporate VTC and Lift control into one mechanism. This will allow them to go back to a simpler camshaft design (no need to route oil through the center for the timing control).

BMW's Valvetronic requires VANOS for timing control, as their rocker system only changes the lift.

Hypothetically, if this system does incorporate both into one, then it will allow them to retain a SOHC design with less compromise. This would lend itself to an updated J series V6.

It would also work equally as well with traditional DOHC design.

I imagine the ultimate implementation would be DOHC with A-VTEC on the intake cam, and traditional 2 stage VTEC with VTC on the exhaust cam. That could be very potent.

This system also has enough control over lift to do away with the throttle system, which would allow a pumping loss and thus MPG improvement like BMW's Valvetronic did.

That is probably where they are getting the 20% fuel economy gain AND more power.

[h22sparkle]

I wonder now what new model honda is gonna get stolen now for its motor lol ,just to be placed into you guessed it another civic. Hopefully the k will go down in value skeet,skeet,skeet.

[gloryaccordy]

LOL! I wondered where you had been.

It is definitely simpler than BMW's system, and actually appears to incorporate VTC and Lift control into one mechanism. This will allow them to go back to a simpler camshaft design (no need to route oil through the center for the timing control).

BMW's Valvetronic requires VANOS for timing control, as their rocker system only changes the lift.

Hypothetically, if this system does incorporate both into one, then it will allow them to retain a SOHC design with less compromise. This would lend itself to an updated J series V6.

It would also work equally as well with traditional DOHC design.

I imagine the ultimate implementation would be DOHC with A-VTEC on the intake cam, and traditional 2 stage VTEC with VTC on the exhaust cam. That could be very potent.

This system also has enough control over lift to do away with the throttle system, which would allow a pumping loss and thus MPG improvement like BMW's Valvetronic did.

That is probably where they are getting the 20% fuel economy gain AND more power.

Yea this system is pretty great. With this, DOHC aren't necessary, although I am a camshaft snob and would prefer separate I/E cams.

I'm still at a loss as to exactly how Valvetronic works... I'm sure in the coming years BMW will probably switch to a different system. Like you and the author said, this system on the intake cam with i-VTEC on the exhaust cam would make for a great combination of power and efficiency. I don't really think VTEC on the exhaust cam is necessary, outside of perhaps preventing blowby at low revs, but w/e...I'd rather them close one exhaust valve and open it up @ high revs than go with the complicated multi-lobe system.

By using this they could save costs on the intake manifold and other components, and with a simplified manifold they can save a lot of space. They would just be trumpets leading to an airbox.

As far as the higher power, that stems from this system enabling Honda to utilize wilder cam profiles. They could literally throw race cams in and still make whatever emissions requirements they have to. It's a pretty nifty system...again, IMO the be all end all of camshaft based valvetrains.

[owequitit]

Yea this system is pretty great. With this, DOHC aren't necessary, although I am a camshaft snob and would prefer separate I/E cams.

I'm still at a loss as to exactly how Valvetronic works... I'm sure in the coming years BMW will probably switch to a different system. Like you and the author said, this system on the intake cam with i-VTEC on the exhaust cam would make for a great combination of power and efficiency. I don't really think VTEC on the exhaust cam is necessary, outside of perhaps preventing blowby at low revs, but w/e...I'd rather them close one exhaust valve and open it up @ high revs than go with the complicated multi-lobe system.

By using this they could save costs on the intake manifold and other components, and with a simplified manifold they can save a lot of space. They would just be trumpets leading to an airbox.

As far as the higher power, that stems from this system enabling Honda to utilize wilder cam profiles. They could literally throw race cams in and still make whatever emissions requirements they have to. It's a pretty nifty system...again, IMO the be all end all of camshaft based valvetrains.

Well, yes, it does make DOHC semi-unnecessary. Since the A-VTEC only functions on the intake side, and thus only changes cam timing on the intake side, you could probably make a good case for seperate exhaust cam phasing , which would require a seperate cam in order to make it truly independent of the intake cam. If you were to phase the single cam with VTC, it would in turn effect the intake. Whether or not A-VTEC has enough adjustability to compensate, I don't know, but it just seems easier to seperate it out.

Also, traditional 2 step VTEC would have the exact same advantage it did in the first generation. It would allow 2 distinct cam profiles for differing engine speeds. Since the exhaust will benefit from higher flow as well, it would be beneficial to have it available there as well. Couple with VTC, it would essentially be i-VTEC on the exhaust cam.

Theoretically, they could implement A-VTEC on both, but their engineers have claimed the gains were marginal for the complexity and cost.

If A-VTEC has the adjustability to use exhaust phasing in conjuntion with A-VTEC without effecting the intake valves (due to the large adjustability) then SOHC would be the only way to go for weight, cost and complexity reasons.

It is possibly the end all be all of cam based timing though.

[owequitit]

Here is a cool link that explains Valvetronic.

http://www.bmwworld.com/technology/valvetronic.htm