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manolis
07-09-2003, 02:10 PM
The main problem of Honda's VTEC, Toyota's VVTLi and Porsche's Variocam Plus is their two step operation.
The main problem of BMW's Valvetronic is its low revs limit and low power output.

Take a look at www.pattakon.com (http://www.pattakon.com).
The system can revs at high revs, and at the same time it is consinuously variable, controlling both, intake and exhaust valves.
It also intergates the operation of an intelligent VVT system.
We need your objections.

Thank you
Manolis Pattakos

jadotch
07-09-2003, 03:57 PM
I can do that with my push rod.

manolis
07-10-2003, 08:31 PM
Originally posted by jadotch
I can do that with my push rod.
Please describe how you can achieve with your pushrods:
continuously variable valve lift from zero (to wipe out the thtottle valve) to a maximum,
and at the same time control of the actual overlap,
and at the same time entry speed of the working gass near to sound velocity, with extreme turbulence and swirl and perfect homogeny of the mixture inside the cylinder at all revs and every load,
and at the same time ability for operation with nearly constant torque from extremely low to extremely high revs.
Your pushrods have to be very special.
Thank you
Manolis Pattakos

Kudosdude
07-14-2003, 05:42 AM
I have taken a good look at your website, please note I know very little in regards to engines, but I think I understand how your system works.

I assume you have taken a look at variocam which is very similar in ideal but uses an electric screw instead (it is quite new I appreciate).

As regards the same effect with pushrods how do you achieve that? Is it a 3d grind on a moveable cam?

Where are you intending to take your idea?

Have you shown it on Eng-tips.net? I think they might be a better site for constructive criticism of your idea.

[i] P.S. What improvements did you get in back to back mpg tests?

manolis
07-14-2003, 09:53 PM
Originally posted by Kudosdude
I have taken a good look at your website ... criticism of your idea.

[i] P.S. What improvements did you get in back to back mpg tests?


Hello.

If you mean the normal ‘variocam’ of Porsche, it is just a hydraulic Variable Valve Timing system (like many others), that is a “phaser” between crankshaft and camshaft.
If you mean the ‘varicam plus’ of Porsche, it is the normal varicam combined to a two step variable lift system for intake valves.
In variocam plus at low revs the intake valve lift is 3 mm and at high revs it is 10 mm. It is achieved using three cam lobes per intake valve, and a pair of coaxial bucket lifters controlled hydraulically in order either to move as a body or to move independently. An intake valve is activated at low revs by the ‘internal’ bucket lifter (this bucket lifter is activated by the soft cam lobe) and at high revs by the external one.
So the variocam plus is just a two step VVA system, and it is not better than the iVTEC of Honda. Think that if you have to operate with either 3 mm valve lift or10 mm valve lift, something is wrong, as the one lift and timing is very soft while the other is wild. So what happens when the operational conditions of the engine demand an intermediate valve lift, i.e. 6 mm? The torque curve cannot be very good again.

It is like having a shoe-shop offering just two sizes of shoes, one for children and one for adults! If you are lucky OK, if you are not…
It is an extreme example, yes, but the reality is not far away with the ‘two step’ systems. Of course these systems are better than conventional, but when you can satisfy all “demands” perfectly, why to compromise in just two lifts?

And it seems variocam plus is used because otherwise Porsche’s sport cars cannot pass the pollution regulations, they lack torque at low revs, they have bad idling, and low drivability.

On the other hand, there was an old variocam of Porsche (again just a Variable Valve Tining system) in which a “tensioner”, acting on the chain between intake and exhaust camshaft sprockets, changes the timing or phase of intake cam shaft.

The new VVA is a continuously variable valve lift system, achieving valve lifts from zero (making possible the elimination of the throttle valve) to a maximum. It also acts as an intelligent variable valve timing system controlling effectively the actual (and not angular) overlap. The way it operates is clear using the animations (use the “one valve in three lifts). If you keep the control shaft immovable, the system is in nothing different than the conventional systems. But as you rotate the control shaft, the lift of all valves in the specific row is changed continuously.

The new system has some similarities to BMW’s valvetronic, but also a lot of differences. For instance it can be applied to intake and to exhaust valves, it can operate at significantly higher revs, it changes the valve lift without affecting the valve opening duration, it can operate without supporting systems like additional VVT, powerful central processing unit, strong electromotor etc.

The new system can be applied to almost all used and new engines. In engines with OHC or better with DOHC the application is easier and more accurate.

I already put two threads in ‘eng – tips’ forums, in two places, before nearly two months. They just deleted the threads and canceled my registration! I do not understand why.
Lately in another forum it was proposed exactly the same: to put the system in the ‘eng – tips’ forums as there are a lot of knowledgeable people there. I asked the guy who proposed it, to create for me a thread at ‘eng – tips’ forum with the new VVA system, as I have no access in this site yet.
He did it a few days ago in
http://www.eng-tips.com/viewthread.cfm?SQID=63556&SPID=71&page=1,
but still there is not even one response from the members of the site. It seems the subject is not of their interest. Let’s hope it will change.

There are not yet official measurements for fuel consumption with and without the new VVA system. And if an accurate measurement of torque or power is an easy thing, the correct measurement of consumption is not.
When the second project will be completed (new straight four 16 valve 1.8 liter engine with fuel injection and ‘as necessary’ construction accuracy) the consumption as well as the power and torque curves will be published in the web site.

Thank you.
Pattakos Manolis

Kudosdude
07-15-2003, 03:49 AM
It's funny you should say you kept getting deleted from eng-tips. I too visited the site for LONG time. I had no problems untill I started responding to questions, or asking a few.

My threads remained for two weeks, some received excellent replies, but eventually they all got deleted. I assumed It was to do with subject matter in my threads.

I wrote 3 e-mails to them and got no-where. A pain really. I wish you luck.

My only other queries regards your choice of engine. Was the choice down to a particular engine at hand, or was the Renault a particularly "GOOD" engine? Have you attempted your system on a newer injected engine?

manolis
07-15-2003, 09:29 AM
Originally posted by Kudosdude
It's funny you should say you kept getting deleted from eng-tips. I too visited the site for LONG time. I had no problems untill I started responding to questions, or asking a few.

My threads remained for two weeks, some received excellent replies, but eventually they all got deleted. I assumed It was to do with subject matter in my threads.

I wrote 3 e-mails to them and got no-where. A pain really. I wish you luck.

My only other queries regards your choice of engine. Was the choice down to a particular engine at hand, or was the Renault a particularly "GOOD" engine? Have you attempted your system on a newer injected engine?

Hello.

The only reason to use the Renault 19 Energy as the base for the prototype is that it was available.

We plan to apply the system in the 16 valve, straight four, 1800 cc engine of the new Ford Mondeo, because this car was the standard winner of its class in all magazines tests.
We plan to use one control lever or “rocker arm” per pair of valves (there is an animation of this ‘common control lever’ in the site) to simplify things. The camshafts will be replaced with wild proper ones (with cam lobes of our design), the intake manifold will be replaced by a set of short bell mouths (without throttles inside) and the injection and ignition will be remapped to suit to the different operation of the engine.
If pistons, connecting rods and crankshaft can reliably rev at 8000 rpm, then the power output could be extreme (a 50% increase seems achievable) without any compromise in medium and low revs quality of operation and without any hole in torque/revs curve.
The target is to achieve:
extreme power at high revs,
with ‘flat’ torque curve from extreme low revs to the revs limit,
with lower and smoother idling,
with better mileage,
with less pollution and
with improved drivability in all conditions.
Yes, it seems impossible today, but we believe it is not.

Thank you
Manolis Pattakos

Kudosdude
07-15-2003, 10:07 AM
My best wishes on your project. Let us know how you get on.

Lagonda
08-05-2003, 01:34 PM
Originally posted by manolis
The main problem of Honda's VTEC, Toyota's VVTLi and Porsche's Variocam Plus is their two step operation.
The main problem of BMW's Valvetronic is its low revs limit and low power output.

Take a look at www.pattakon.com (http://www.pattakon.com).
The system can revs at high revs, and at the same time it is consinuously variable, controlling both, intake and exhaust valves.
It also intergates the operation of an intelligent VVT system.
We need your objections.

Thank you
Manolis Pattakos

BMW's VVT-system is called VANOS. Not Valvetronic, that's something else.

Valvectronic Link (http://www.bmwworld.com/technology/valvetronic.htm)
VANOS Link (http://www.bmwworld.com/technology/vanos.htm)

manolis
08-05-2003, 09:22 PM
Originally posted by Lagonda
BMW's VVT-system is called VANOS. Not Valvetronic, that's something else.

Valvectronic Link (http://www.bmwworld.com/technology/valvetronic.htm)
VANOS Link (http://www.bmwworld.com/technology/vanos.htm)

Valvetronic is the last (and biggest in BMW's history, as BMW claims) improvement. It is a continuously variable valve actuation system.
In valvetronic there is a basic mechanism which controls the intake valve lift from about zero (for idling) to a maximum value. This basic mechanism cannot work without the assistance of many supporting subsystems.
One of them is the VANOS, which actually is a wide angle continuously Variable Valve Timing system.
So, in every valvetronic (used on all new four cylinder and eight cylinder engines of BMW) there is a double Vanos.
Valvetronic is a commercial success. Nevertheless it has many inherent weak points.
The new VVA, presented in www.pattakon.com seems better from many points of view.
Your objections?

Thank you
Manolis Pattakos

Cedric
08-13-2003, 11:57 AM
I find your system quite remarkable. Where are you planning on taking this to? Does the system require to be adjusted regularly or does it run like a clockwork? Has the automotive industry shown you any interest?

manolis
08-20-2003, 10:21 PM
Originally posted by Cedric
I find your system quite remarkable. Where are you planning on taking this to? Does the system require to be adjusted regularly or does it run like a clockwork? Has the automotive industry shown you any interest?

Hello.
We plan to apply the system as ‘add on’ or ‘retrofit’ on existing engines.
Compare the system to BMW’s valvetronic, which has been proved reliable and adjustment free in practice. The new system, compared to valvetronic, seems better as it has fewer and lighter parts, it has fewer interfering joints for conveying the motion from cam lobe to valve and it has no wear concentration points.
No, there is no interest yet from automakers.

A misunderstanding about the system is its constant timing compared to other systems of variable lift and variable duration/timing.
At first look systems like BMW’s valvetronic change the valve lift, the duration and the timing. So they are THE solution of the problem. But looking more carefully, the valvetronic and the similar systems do not control duration or timing. In order to change the valve lift, they necessarily change and the duration and the timing. Then, using additional variable timing systems, controllers, drive by wire etc they try to fix the operation.
Now take a look at the new VVA system. It keeps the timing unchanged. So the overlap is constant AS REGARDS THE CRANKSHAFT DEGREES. But, from the working medium point of view, the actual overlap depends on how much time the intake and exhaust stay opened together AND ON HOW EASILY intake and exhaust communicate during this time. The new VVA changes dramatically the ‘how easily communicate intake and exhaust during overlap time’, offering actual overlap which is many times lower than conventional engines (without VVT) at low revs and partial loads, while at high revs and heavy load it offers wilder actual overlap. This makes the new VVA a “complete solution” without the need of supporting subsystems. The typical rotation of the throttle valve, in conventional engines, becomes a rotation of the control shafts in the new VVA system, and this is all the control of the engine.

Thank you
Manolis Pattakos