Need Engineer Opinions

linewarbr · **Posted:** Fri Apr 23, 2010 11:58 am

Can some engineers chime in on the validity of this technology?

viewtopic.php?f=15&t=52115

geordi · **Posted:** Fri Apr 23, 2010 1:42 pm

Gasser technology! Patooie!

Other than that... I am not smart enough to make a determination about it. It looks interesting, IF it is functional, but I'm not entirely sure what it is doing to the airstream. That was the part I couldn't get with only their dyno chart images to work from. :dizzy:

dieseldoesit · **Posted:** Fri Apr 23, 2010 2:16 pm

It looks like it is specific to only a narrow operating rpm range.

Squeeto · **Posted:** Fri Apr 23, 2010 3:57 pm

I remember giving a couple hitch hikers in suits a lift through the city who had put all there money into a carburetor they designed (and had with them). It also was a venturi type system. It swirled the intake air and at a faster rate than normal which provided better ionization. They were after better fuel economy though.

CATCRD · **Posted:** Fri Apr 23, 2010 4:00 pm

I'm a mechanical engineer, and the scientific principles in the description of that device are pretty legit. And from their dyno charts, it seems to work at almost all rpms. Basically, when the intake valve opens, the piston is sucking air from a small "prechamber" in the intake runner, which starts at atmospheric pressure. This is obviously easier than sucking against air that is already at a vacuum. As the piston keeps sucking, of course, the pressure in the intake runner decreases, but the piston ends up wasting less work on its way down.

This is one reason that diesels are more efficient than gassers - we don't have to suck air past a throttle plate. And since we can meter the amount of fuel injected and don't have pre-ignition, we don't need all the PRV devices this group just invented.

BMW is using this principle in their valvetronic engines. They don't have throttle plates - they can infinitely vary how much the intake valves open.

Sir Sam · **Posted:** Fri Apr 23, 2010 5:59 pm

CATCRD wrote:

I'm a mechanical engineer, and the scientific principles in the description of that device are pretty legit. And from their dyno charts, it seems to work at almost all rpms. Basically, when the intake valve opens, the piston is sucking air from a small "prechamber" in the intake runner, which starts at atmospheric pressure. This is obviously easier than sucking against air that is already at a vacuum. As the piston keeps sucking, of course, the pressure in the intake runner decreases, but the piston ends up wasting less work on its way down.

This is one reason that diesels are more efficient than gassers - we don't have to suck air past a throttle plate. And since we can meter the amount of fuel injected and don't have pre-ignition, we don't need all the PRV devices this group just invented.

BMW is using this principle in their valvetronic engines. They don't have throttle plates - they can infinitely vary how much the intake valves open.

x2, without really sitting down and reading all about it this doesn't seem like it will work for us with a diesel.

In a diesel fuel is injected after the intake stroke to pull in air, because the fuel is injected after this air injestion we get more air pulled in per stroke. In a gasser the air/fuel mixture is pulled in, meaning some of the air is displaced by fuel. Because of this diesels have a greater pumping efficiency.

Sir Sam · **Posted:** Fri Apr 23, 2010 8:07 pm

After looking through it and getting a better feel for it I see what all is going on. I actually had a very similar idea to this starting a few years back, their execution of it is a little different than what I had in mind, but is also more practical.

One of the interesting things I find in engineering is that often engineers of different groups come up with the same ideas, and either similar or identical execution.

Ripple · **Posted:** Fri Apr 23, 2010 9:46 pm

The way i see it, they still throttle the engine by limiting airflow, throttle blade, fancy aerodynamic venturi, same difference, limits air flow and reduce pressure for the intake stroke of the cycle. the combustion chamber is what turns fuel and air into power, and the CC does not care what the intake looks like, just what comes in the intake port (pressure, temperature, Fuel/air ratio, burn characteristics of that mixture)

I'm not saying that they did not increase power and increase MPGs, but it could be explained by changing the mechanics of the intake manifold, which they obviously did.

my favorite "free" MPG modification is the Smokey Yunik hot vapor engine, which should work and is backed up with math. the key thing to keep in mind is that at WOT all spark ignition engines have basically the same peak efficiency, but increasing the part-throttle efficiency is what gives the crazy MPG numbers, most 2-4 valve engines peak around 28-30% BTE(brake thermal efficiency), but all are only 12-15% BTE in the operating range they are actually used in. A great example/interpretation of this idea is the SwRI HEDGE concept engine as it comes from Ford (ecoboost 1,2 and 3) and others we are seeing actually be used by large OEMs.

linewarbr · **Posted:** Sat Apr 24, 2010 8:41 am

Thank you for the replies. One of my first questions for him was, "What about the brake booster?" Apparently there is more cost involved, because you need to modify the engine bay to accept either a small electric vacuum pump, or modify the belt to accept a pulley-powered vacuum pump.

dkenny · **Posted:** Sun Apr 25, 2010 5:37 pm

uh??

in the case of a gas engine..yes, they must use something to create a vacuum for brake boost..or do they??
consider a different diesel..say a Dodge Cummins diesel..yes it has a vacuum pump..for the HVAC system..it uses the power steering pump for a brake booster..well so much for need a vacuum pump on a gasser using this system.

great idea..for a gasser..won't help a diesel..why?? we have a turbo that pressurizes the intake? so no vacuum..
2nd..our fuel is pumped directly into the cylinder..the only thing before this is AIR..

just some idle thoughts..since this isn't about a right or wrong..can it work yes.
fyi..do some reseach into old popular mechanics around 1981/82 and mechanic section..where guy used a turbo not for boost but mixing the air/gas. might have run 1-2 psi instead of a vacuum..but intake manifold temps with 400F posting.php?mode=reply&f=5&t=52116#

time to help with dinner...

-dkenny

jnaut · **Posted:** Mon Apr 26, 2010 6:31 pm

Squeeto wrote:

I remember giving a couple hitch hikers in suits a lift through the city who had put all there money into a carburetor they designed (and had with them). It also was a venturi type system. It swirled the intake air and at a faster rate than normal which provided better ionization. They were after better fuel economy though.

My guess is they're still hitchhiking.

Squeeto · **Posted:** Tue Apr 27, 2010 12:13 pm

Or paid off like Pogue?

danoid · **Posted:** Fri Apr 30, 2010 10:28 pm

If, in designing an engine, you need to resort to premixing fuel with air, or spark plugs, YOU HAVE FAILED. Go work in the ashtray lab.

CATCRD · **Posted:** Sat May 01, 2010 11:00 pm

Amen.

UFO · **Posted:** Tue May 04, 2010 1:28 pm

As pointed out, it has some potential in reducing throttling losses. But the efficiency improvements still won't rival a diesel because you still have to have a pi$$ poor compression ratio to prevent detonation. Increase compression and inject fuel directly.

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