Air-take verses direct hho injection into manifold

[bradlington]

Air intake or PCV injection:

My question to think about is this - most information tends towards air intake injection .I have an issue with this due to the PCV system also drawing air from the air-intake .The science behind the mixing of hydrogen and oxygen with crank gases is possibly endless and not the real question .

In my case I have a modified intake with a performance Cone filter directly onto the throttle body .
The HHO is currently injecting into the center of the cone via a chassis through fitting .

During de-acceleration and long downhills at low speed as well as any other time the foot is off the pedal - what will happen - the butterfly closes and only a small portion of air is actually pulled into the manifold.I assume at this stage the excess hho will be lost to vent to atmosphere.

So the question would be this - would placing the hho into the manifold be more beneficial and provide better gains as it is constantly being used in opposed to air-filter intake where possibly only a portion is actually used.

Anyone done a more scientific look into this one .

My PCV is venting to atmosphere so I do not have PCV injection option - however I will be adding a fixed connection in place of the PCV valve to inject direct in future to make my own observations .

Thanks
Bradley

[RedDevil]

I think the majority opinion here is that HHO is a synonym of scam.
It poses no benefit at all as there's no way to overcome the energy lost in generating it.

Some research suggests minute amounts of hydrogen gas can have a disproportionally large gain in some very specific conditions (IIRC purified octane in a 30:1 compression rate diesel type engine), but these conditions are not present in automotive engines.

Nor do performance air intakes generate any economy benefit at all, as the engine would run at reduced throttle anyway. The less restriction the air filter provides, the more the throttle valve will close for the same intake pressure at the cylinder head.

As for excess HHO venting out: even if the throttle valve closes, it will let several liters per second by. If you have instrumentation that shows RPM and air intake pressure you can calculate how much.
For instance, my Insight has a 1339 CC engine. If it idles at 1000 RPM it pulls 500 times its displacement in a minute (it is 4 stroke after all). The intake pressure typically drops 80% idling, so that would be equivalent to 100 times its displacement a minute, 134 liter per minute, 2.23 liter per second.
Your HHO generator will produce only a minute fraction of that amount, which should all get sucked into the air intake even when decelerating or idling. I expect no effect to be noticeable.

That said, there's nothing wrong with trying things out.
The best way to test the effectiveness, or lack thereof, is by doing a series of ABA test in constant conditions (warm engine, no traffic, low wind, constant temperature, same route).

[oil pan 4]

The only time a performance air intake will increase fuel economy is if it's on a diesel.

[niky]

Whenever a performance intake increases gasoline economy, it's likely an accidental side effect of it changing the reading at the mass airflow sensor and causing the engine to run slightly leaner.

[Isaac Zackary]

Originally Posted by oil pan 4

The only time a performance air intake will increase fuel economy is if it's on a diesel.

This is basically true.

On a gasoline engine most of the time you are running around with the intake choked off by the throttle plate. Making a better intake on a gasoline engine will do absolutely nothing for fuel mileage, unless you drive everywhere at full throttle.

[teoman]

So maybe beneficial for pulse and gliders.

[cRiPpLe_rOoStEr]

Did you notice any actual fuel-efficiency improvement with HHO? BTW many so-called HHO kits in fact only pour steam to the intake. Probably water injection would make more sense.

[niky]

Originally Posted by cRiPpLe_rOoStEr

Did you notice any actual fuel-efficiency improvement with HHO? BTW many so-called HHO kits in fact only pour steam to the intake. Probably water injection would make more sense.

Properly fitted, water injection saves fuel on diesels. But I don't think you can guarantee fuel savings on ALL diesels without at least some ECU tweaking.

On gasoline, it might help on turbo cars, but from what I've seen, the effects on economy gasoline engines is minimal... usually a nominal power bump, if any, and at a level that doesn't justify the price of installation.

[cRiPpLe_rOoStEr]

Originally Posted by niky

Properly fitted, water injection saves fuel on diesels. But I don't think you can guarantee fuel savings on ALL diesels without at least some ECU tweaking.

Even in a mechanically-governed Diesel engine, some higher amount of moisture suspended in the air already leads to some enhancement to the efficiency.

On gasoline, it might help on turbo cars, but from what I've seen, the effects on economy gasoline engines is minimal... usually a nominal power bump, if any, and at a level that doesn't justify the price of installation.

With the EFI trimming the fuel to keep power and torque figures at the stock parameters, the cooling of combustion chambers provided by that small amount of water allows a slightly leaner burn even in a naturally-aspirated gasser with port injection.

[Isaac Zackary]

Originally Posted by teoman

So maybe beneficial for pulse and gliders.

Yes. The ideal gasoline engine, or even diesel engine for that matter, would have only one throttle position. Then you pulse and glide it. Or figure an efficient way to store and then apply it's pulsed energy. Some hydraulic pumps and motors and hydraulic accumulators are over 98% efficient.

But even then, just widening the intake or exhaust doesn't mean better efficiency. Everything in the intake and exhaust is pulsing with each intake and exhaust stroke. Harmonics become much more important here, which is affected greatly by runner diameters and lengths as well as resonate chamber designs. In other words, widening things can be just as bad as making them more narrow. And using the harmonics with finely tuned intakes and exhaust systems to get more air and fuel and exhaust in and out of the cylinders doesn't always equate to better fuel efficiency either.

I had stock exhaust and intake on my 1985 VW Golf diesel which the exhaust was less than 2 inches in diameter IIRC, and I got as much as 60mpg in it.