Omni valves (interesting valve technology)

[defiance]

Might be a scam, useless product, whatever; I have no idea - but it's interesting at least:

http://www.omnivalves.com/news.html

Some of the claims they make are pretty outlandish, but the overall concept seems pretty cool (to my not-a-fluid-dynamics-expert-self).

Basically, the valves have a pressure-responsive sub-seat that remains closed any time that:

-The valve lift is below 0.160" (the valves can be manufactured in variant lifts, but this is the 'standard')
-The manifold pressure is higher than the piston pressure.

Basically, the result is that a very high-duration cam can be used, and the flow of exhaust gas out the intake port is effectively stopped.  The claim is that this stops the low-rpm torque loss normally associated with a high-rpm cam. 

There are also some claims about emissions (because the car can idle lower, emissions are dramatically reduced), mpg, etc....

So what do you guys think?  Fraud, or is this possible?

Personally, it seems like it would work to me, but I have to worry about longevity; that's a lot of abuse...

[Chryco Psycho]

Plausable for sure

[tieman55]

Hello and thanks for checking out my baby the  OmniValves!

If you have any questions about the valve please ask away. 

They really work great and if any body has a project they are working on where they would like to test them, let me know and I will see if I can get you a set for free.

Thanks again, Mike @ omnivalves.com

[bordin34]

I still dont get how they work is there an easy way that you could explain it?

[d72hemi]

Hello and thanks for checking out my baby the  OmniValves!

If you have any questions about the valve please ask away. 

They really work great and if any body has a project they are working on where they would like to test them, let me know and I will see if I can get you a set for free.

Thanks again, Mike @ omnivalves.com

Hello Mike,

Welcome to the site. We have many "numbers guys" on this site, including me. Do you have any dyno pulls that compare the same engine before and after the new valves are installed? I am getting ready for ready for 440 build and if these work as advertised (documented) I would be interested in them. Have you had any V8 engines run with your valves? I am not sure that I am fully understanding how your valves operate; does the "outer" portion of the valve open early (in reference to the normal opening by the cam) when the cylinder pressure is less than intake manifold pressure; allowing air/fuel in sooner? Would the valves work with turbo or supercharged engines as well?

Ian

[Troy]

There's a pretty decent write up (to me any way) on their site. Go to their home page and click the "Volumetric Efficiency" link. It looks to me like the valve is pushed open as usual by the pushrod *but* a mechanism within the valve actually keeps it shut until their is vacuum from the piston (meaning it's no longer expelling exhaust gas). That's as much as my limited knowledge allows me to figure out. I assume there is some inefficiency by having valve overlap but it's inherent in a purely mechanically timed combustion engine?

Troy

[defiance]

I've been doing a lot of digging since coming across their site, so I might be able to answer a few of the questions myself, but I've got PLENTY more questions myself!

As far as I've found, I know they've tested it on small air-cooled VW engines first, then later on a 327 SB Chevy.  I don't think they've done a Mopar yet.  I haven't seen any dyno specifics, but I know they mentioned dyno pulls.

As for function, from what I can tell, the airflow actually drives the movement of the ring; When airflow begins to move in 'reverse', it sucks the ring closed (as long as the valve lift is within range of the seat, which is usually around .16" lift of so).  When air begins to move 'forward', it moves the ring into the normal position.

As far as I can tell, the main valve body moves just like a normal valve, and it still controls the 'maximum' lift at any given time, the 'ring' just allows it to close early or open late if pressure is 'negative'.  Thus, you can run higher duration without as much worry about reversion.

At least, that's my understanding...

I still admit I'm worried about longevity; with only a few (I think?) engines running this, how is it possible to really be sure about the reliability? 

Also, they have to be a lot heavier, right?  so, you'd have to stiffen valve springs to make up for it, which would lose a bit of total HP...?

Also, the fact that the 'heads' of these valves are bigger means it would be difficult to use them in a tight quench closed chamber configuration...



It would be SO nice to be able to build a high-RPM motor without sacrificing low-RPM torque, though...   TRUE street-strip, you know...

[d72hemi]

Tieman55,

Where did you go? This is interesting!

Ian

[Steve P.]

I would like to see exhaust valves cut convex instead of concave. I think it would be a tremendous help by getting rid of some turbulence and helping to direct outgoing/spent exhaust.

[d72hemi]

I would like to see exhaust valves cut convex instead of concave. I think it would be a tremendous help by getting rid of some turbulence and helping to direct outgoing/spent exhaust.

That would also increase the compression ratio, right? do to less volume in the head? but how would that affect flame travel? Also could the convex exhaust valve push the charge away from the port, into the cylinder wall, and the other side of the combustion chamber? I am no expert but, I would think other restrictions such as the port size/shape, headers, and the rest of the exhaust system being improved, would out weigh the flow change and increased valve weight. Don't get me wrong, I would love to try it. I am just throwing some thoughts out there. I wonder if something like that has ever been tried?

Ian