inlet swirl again?!?

[JayMaechtlen]

A while back there was much discussion of inlet swirl.
Powerdyne is now promoting it.
comments?

http://www.powerdyne.com/powerplates.htm

"
PowerPlate™ intake spacers feature a cnc machined helix bore that "spins" the incoming air charge. This turbulence increases the atomization of the air/fuel for more efficient combustion. The result is, better fuel economy, more horsepower, and more torque! PowerPlates™ install in minutes and require no mechanical experience or special tools.
"



Jay Maechtlen

 

[patprimmer]

Combustion efficiency is very high in a modern engine, so why do we need to improve it.

Swirl absorbs energy, which I expect shows up as reduced volumetric efficiency which means less power in this case.

Less power equals less fuel.

Swirl might atomise the fuel better, but I expect, the higher density of the fuel vapour, and especially the fuel liquid, means the fuel will tend to seperate to the outside of the cantrifuge, thus potentially creating rich and lean cylinders, resulting in missfires, extra NOx, HCs and increased fuel consumption, or even holed pistons.

Regards
pat

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[Andy330hp]

And how do they explain it's benefits when mounted behind the throttle body of an MPFI car? It promotes better mixture of the air with...AIR??? I don't get it....

 

[SBBlue]

Swirl is a big deal in diesel engines -- at least swirl in the cylinders.

This device looks to me like something that's bolted between the carburator and intake manifold. I would be surprised if it supplied much "swirl" at all. And Andy's point is very well taken -- what good does it to do mix air with air?

If inlet swirl is all that important -- why not just add a fan following the carburertor/fuel injector that really swirls the air?

 

[maniacle]

Its usually entertaining to see performance enhancers that end up inhibiting flow, increasing air velocity and dopping manifold pressures, etc. But i still dont think this can compete with the ebay specials. i.e. the tubular electric fans that install before your throttle body, and act as a supercharger or turbocharger when you "flip the on switch."

I think my favorite part of those was they werent even rated to flow enough air for the engine halfway to redline. But im sure that low end torque was just....unbelievable.

 

[NJBuis]

On the "swirl market" another device is promoted from Australia: The Hiclone (in the UK

http://www.hiclone.co.uk).

A quote from their website:

What is Hiclone?
Hiclone is a non moving ring shaped device that fits inside the air intake system of an internal combustion engine between the air filter and the engine manifold. ....Robustly constructed of stainless steel, it vigorously swirls the air as it is sucked into the engine, improving volumetric efficiency and exhaust gas scavenging which increases torque, reduces emissions and improves mileage.

The Test Results, etc. are impressive and it would be foolish not to install one... or?
Does this device fit under the label "placebo effect" or have all the car makers been sleeping? Is it worth trying or nonsense?

Would appreciate your opinion.

Nico Buis
The Netherlands

 

[PoFo]

Swirl or turd
Over the years I’ve tried most things and the only thing that showed any improvement was I piece of fine mesh under the carb, any other object in the air stream just slows things down and reduces power.
Even the mesh lost a couple of brake horse but it picked up torque and made it flatter and wider with 95% of peak torque available for 3500rpm with a table top peak rather than a spike (very easy to drive engine).
I’ve tried little propellers, static blades, swirls machined in ports but I have found that a step in the manifold to head works on some engines but not all, flow is a very difficult science to work out and impossible to predict (only a flow bench and thousands of hours testing gives a small window into this world!)
Po-Fo.

 

[Andy330hp]

One thing I wonder about these tests: they always quote "HC emissions reduction of 50%, CO reduction of whatever percent..."

Percent of what?

It is not uncommon, after warm, for a new vehicle to have 2500 rpm no-load HC's of 5-10 ppm. So, if the test vehicle had 4 ppm, and then later in the day with "the wonder fan" or whatever product installed it happened to hit 2 ppm, is that their amazing 50% reduction?

 

[Hasbro]

I have a relation that ownes/operates a hi volume trailer sales in Wa. State. He has these spacers and sells the heck out of them. I was told about them and laughed. I spoke with one of the employees about them while visiting one afternnon and he said he laughted the same. He said " Let me have one of those things" and installed it on his injected Camero. He came back with a smile on his face in dis-belief. Took it back off and drove it again and said it was a notable differance. He bought it. The customers say they can really notice the differance in towing I'm told.

John Haskell
Aire Research Engr.

 

[enginead]

Swirl or turd I like it

Swirl is important in engines (gasoline and diesel) as it (all else being equal) increases heat release rate and gets closer to constant volume combustion and thus (theoretically at least) increases thermal efficiency. However, it also increases heat transfer from the chamber to the coolant thus reducing the positive effects. In reality it's a compromise between speeding up combustion and limiting losses due to heat transfer. In addition, this trade-off varies with engine speed as combustion rate scales almost linearly with rpm (i.e. 5-95% heat release is half the duration at 4000rpm as it is at 2000rpm) and is also very application specific as the valve timing, spark timing, fuel injection timing etc... also effect burn rate and thus the shape of the trade-off curve.

I've had this argument/discussion with so many half-witted door to door salesmen types pedalling this rubbish. OEMs spend literally millions developing new engines to meet power/fuel consumption/emissions targets, does anyone really believe a £50 bolt on device is going to transform their power/fuel consumption/emission blah, blah, blah!!

I've tested several of these miraculous devices and fuel additives on testbed and found at best no difference, at worst significant reductions in all above mentioned factors. I've even been accused of being paid off by some OEM when the results didn't show what the guy selling the stuff wanted. No number of unsigned, undated letters from satisfied customers will ever convince me that these devices are anything other than a complete waste of time and money.

Saying that the guys selling it always drive a better car than I do, maybe scientific method and sound engineering isn't the way to go in this marketing lead world (don't get me started!!)

 

[Tmoose]

A certain amount of swirl during the compression stroke can be a good thing for overall combustion "efficiency."
Maybe it can be induced (violently?) directly in the chamber during compression via squish/quench. Somebody (Weslake?) convinced Jaguar that Having the inlet port(s?) enter the cylinder at an angle induced some swirl during the intake stroke that persisted during the compression stroke, and helped sowmthing or other.

http://www.jagweb.com/jagworld/xk-engine/page1.html

shallow angle 4 valve pent roof chambers automatically impose a vertical tumbling swirling motion during the intake stroke.

Even 'Murcan V-8s and their derivative V-6s have changed their thinking about combustion chambers. I bet there is something to swirl.

I would not dare to guess Whether a spiral thing in the intake can do it.

 

[patprimmer]

I would dare to guess that a spiral thing in the intake does not do it.

I would also dare to guess that swirl in the chamber is only benificial towards the end of the compression stroke and early in the power stroke, so as to aid flame spread.

In my opinion, swirl after the introduction of fuel, and before the compression stroke is likely to have a centrifuge effect and send the heavier vapours and especially the liquid fuel droplets to the outside of the swirl.

I expect that this is likely to put the rich mixture a long way from the spark plug, possibly causing miss fires if the mixture is not a bit on the rich side.

While good mixing of fuel and air, and accelerated flame propagation are both desirable, it is not a simplistic situation, and the effects at the most probable engine speeds and the most probable throttle positions should be most considered, but all conditions should be considered.

This will vary from engine to engine.

As combustion efficiencies are already very good re complete combustion of the fuel, what needs improving?

The conversion of the heat from combustion to motion is not very efficient, so it does leave room for improvement. I expect that one area to improve this would be to better control the time and speed of combustion so that less energy is used on the compression stroke, and more energy is extracted from the expanding gasses from the combustion process.

I guess, if we could ignite the fuel closer to TDC, and burn it a lot faster, so as to have it all burned before 90 deg ATDC, we could improve our conversion of heat to motion. This factors influencing this should mostly occur near TDC, and will be influenced by valve position and shape, port angles, chamber shape, piston shape, squish areas, spark plug location(s), flame travel slots or channels, valve timeing overlap, coolant flow, pattern of fuel flow into the airstream.

If we could introduce the fuel biased towards the centre of the centrifuge, we might compensate accurately and get good distribution of fuel within the chamber, but the amount of compensation would vary greatly with air speed, and be upset my reflected waves and reversion.

I expect that for this sort of compensation to work under a wide range of conditions, it might require multiple or movable injector nozzels for each cylinder, controlled by a computer program that might do NASA proud.

Sorry about the rave, but the sugestion of a piece of bent tin under the carby being able to do this effectivly, just seems so simplistic, and the suggestion that the trillions of manhours that have gone into petrol engine development over the last 130 years, was done by people so incompetent, that every one of them missed such an easy fix, is not only incredible, but also insulting to every engineer ever involved in the development of the petrol engine.





Regards
pat

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