Hydrogen Generator Experiment

[tjts1]

Originally Posted by Istas

You're suggesting that we should toss the idea out without testing it just because you don't think it's valid, and you're flinging insults as well.

Oh no its been tested over and over again. Search this forum. Plenty of A-B-A tests have been done. It doesn't work.

[stevey_frac]

Originally Posted by tjts1

Oh no its been tested over and over again. Search this forum. Plenty of A-B-A tests have been done. It doesn't work.

This is wrong though. They tested the kits. The kits provably don't work.

But hydrogen fuel enrichment that enables a lean burn engine to run very lean at low loads is more efficient. Provably so. The kits just don't have the sophistication to lean out the AFR. To do it properly, you'd have to add a wideband O2 sensor, and trick the ECU into running quite lean if the load was low.

Better yet would be to have a wideband, and an ECU with lean cruise built in.


Need proof? Check out this study:

ScienceDirect - International Journal of Hydrogen Energy : Hydrogen enrichment for improved lean flame stability

(i hope that link works)

Alternatively, do a google search for hydrogen fuel enrichment.

[dcb]

well, if hydrogen fuel enrichment is only good for cutting idle fuel consumption in half (source), I have a much simpler and infinitely more effective solution. Turn off your dang engine INSTEAD of idling.

lean burn does help, but it is not the ultimate solution, it is a band-aid for an over sized engine. bsfc naturally peaks around stoich because you aren't passing unburnt fuel (rich) or pumping unused air (lean).

[suspectnumber961]

theoretical science vs experential science? Some talk from theory (?) and some just do it.

A lot of pooper-oners who can't seem to get off the porch?

[stevey_frac]

Originally Posted by dcb

well, if hydrogen fuel enrichment is only good for cutting idle fuel consumption in half (source), I have a much simpler and infinitely more effective solution. Turn off your dang engine INSTEAD of idling.

lean burn does help, but it is not the ultimate solution, it is a band-aid for an over sized engine. bsfc naturally peaks around stoich because you aren't passing unburnt fuel (rich) or pumping unused air (lean).

This is true. So, do we wait for the 300 CC engine with a turbo that puts out 50 hp?

Truthfully.... that'd be kind of sexy...

[john_bud]

Originally Posted by stevey_frac

Need proof? Check out this study:

ScienceDirect - International Journal of Hydrogen Energy : Hydrogen enrichment for improved lean flame stability

(i hope that link works)

Alternatively, do a google search for hydrogen fuel enrichment.

Did you read the study closely? They added 20% hydrogen to the combustion mix. That is a HUGH amount of hydrogen. They also added pure 100% hydrogen. The typical home made HHO devices will, on a good day, generate 0.5 to 1.0 liter per minute of total gas. That's H2, O2 and H2O vapor. The hydrogen content of the device effluent stream is about 1/2 by volume with the remainder being the oxygen and heated water vapor. Do the math on an engine to see the volume needed to reach 20%.

A typical 2.0L 4 cyl engine on the freeway will run about 2000 rpm. (Makes the math easy) A 4 cycle engine will inhale once per 2 revolutions, so at 2000 rpm's that 1000 inhales. If you are at full throttle, it will inhale 2000 liters of air per minute. 20% of 2000 liters is 400 liters. So, to get the full benefit of hydrogen fumigation, you would need a system that could produce a variable volume of hydrogen up to 400 liters per minute for a 2.0 4 cyl engine. If you make a good "HHO" system it may make 1 liter of gas per minute with 10 amps supplied. (assume it's all H2). To reach the 400 liter of hydrogen the study called for you will need 4000 amps .


Think about this; How much lag time is there between the peddle getting pressed and the hydrogen being produced? Obviously, you need different amounts of hydrogen when the engine is idling at a stop light compared to accelerating when the light turns green, right? So you really need a system that can fumigate a small amount (5-10 liter hydrogen per minute) at idle then increase to 400 liter per minute as you hit the accelerator without a lag. Then you need the system to be able to stop the fumigation when you let up the peddle (or the engine will continue to rev as you try to coast or stop!!).

The aspect of matching the volume of hydrogen to the engine throttle opening / rpm / fuel flow is never discussed on the sites that sell the systems. Ever wonder why?

[stevey_frac]

Originally Posted by john_bud

Did you read the study closely? They added 20% hydrogen to the combustion mix. That is a HUGH amount of hydrogen. They also added pure 100% hydrogen. The typical home made HHO devices will, on a good day, generate 0.5 to 1.0 liter per minute of total gas. That's H2, O2 and H2O vapor. The hydrogen content of the device effluent stream is about 1/2 by volume with the remainder being the oxygen and heated water vapor. Do the math on an engine to see the volume needed to reach 20%.

First of all, I said the kits didn't work, and there are many reasons for that, the primary one in my mind being, they can't do anything to lean out the fuel mixture so it dosen't matter how much hydrogen they produce.

Originally Posted by john_bud

A typical 2.0L 4 cyl engine on the freeway will run about 2000 rpm. (Makes the math easy) A 4 cycle engine will inhale once per 2 revolutions, so at 2000 rpm's that 1000 inhales. If you are at full throttle, it will inhale 2000 liters of air per minute. 20% of 2000 liters is 400 liters. So, to get the full benefit of hydrogen fumigation, you would need a system that could produce a variable volume of hydrogen up to 400 liters per minute for a 2.0 4 cyl engine. If you make a good "HHO" system it may make 1 liter of gas per minute with 10 amps supplied. (assume it's all H2). To reach the 400 liter of hydrogen the study called for you will need 4000 amps .

I don't know if it's wise to assume 100% volumetric efficiency, or that i'll be going down the highway at full throttle. Most of the time i'm way down near 30% throttle, and my car definately dosen't get 100% volumetric efficiency at any throttle, and at any RPM. The goal is not to make a drag car more fuel efficient. Never the less, you are correct in that it would take substantial power to add in 20% hydrogen. That being said, 20% hydrogen lets them massively lean out the AFR while maintaining burn stability. Personally, i'd be trying to target perhaps 5% hydrogen, and an AFR of 16:1 or 17:1.

Originally Posted by john_bud

Think about this; How much lag time is there between the peddle getting pressed and the hydrogen being produced? Obviously, you need different amounts of hydrogen when the engine is idling at a stop light compared to accelerating when the light turns green, right? So you really need a system that can fumigate a small amount (5-10 liter hydrogen per minute) at idle then increase to 400 liter per minute as you hit the accelerator without a lag. Then you need the system to be able to stop the fumigation when you let up the peddle (or the engine will continue to rev as you try to coast or stop!!).

The aspect of matching the volume of hydrogen to the engine throttle opening / rpm / fuel flow is never discussed on the sites that sell the systems. Ever wonder why?

The same thing happens when you hit the gas peddle on you car with respect to air. There is no magic device that allows the air in the intake manifold to suddenly jump from 5 psi to 14psi (MAP reading). As a result, the AFR dosent' perfectly track at 14.7:1. It wanders. Richens up when you punch the peddle, leans out when you suddenly let off. That's fairly normal, and the same would be acceptable in a hydrogen system.

Also: You could have a hydrogen system that could go from full production to nothing back to full in a milisecond if it was electronic. With ease my friend.

[stevey_frac]

A problem that I don't think anyone has mentioned, but which could cause a lot of problems is hydrogen embrittlement (sp??).

[cfg83]

stevey_frac -

Originally Posted by stevey_frac

...

I don't know if it's wise to assume 100% volumetric efficiency, or that i'll be going down the highway at full throttle. Most of the time i'm way down near 30% throttle, and my car definately dosen't get 100% volumetric efficiency at any throttle, and at any RPM. The goal is not to make a drag car more fuel efficient. Never the less, you are correct in that it would take substantial power to add in 20% hydrogen. That being said, 20% hydrogen lets them massively lean out the AFR while maintaining burn stability. Personally, i'd be trying to target perhaps 5% hydrogen, and an AFR of 16:1 or 17:1.

....

That's inline with the findings of this research study :

Welcome to IEEE Xplore 2.0: Fuel consumption and emission of SI engine fueled with H2-enriched gasoline - August 1989

Abstract
A study of the effect of the amount of hydrogen on the fuel consumption and emission of a spark ignition (SI) engine is reported. In the first stage, dynamometer test results for a wide range of engine speeds, engine loads, equivalence ratio, and hydrogen enrichment under steady-state operation were obtained, and the engine requirements for minimum BSFC were specified. In the second stage, an onboard, online hydrogen generator was developed and employed to provide the required amount of hydrogen. The hydrogen was produced by a steam reforming process. A detailed model for simulating a spark ignition engine fueled with hydrogen-enriched gasoline was developed and used to predict the optimal amount of hydrogen supplement as well as the corresponding MBT, optimal throttle position, and emissions level of CO, HC, and NOx

It concluded that the "sweet spot" for hydrogen to fuel mass ratio was 2-6%. Anything over 6% resulted in marginal (aka not worth it) gains.

However, keep in mind that this was done in 1989 with a carburated engine.

CarloSW2

[john_bud]

Originally Posted by stevey_frac

The same thing happens when you hit the gas peddle on you car with respect to air. There is no magic device that allows the air in the intake manifold to suddenly jump from 5 psi to 14psi (MAP reading). As a result, the AFR dosent' perfectly track at 14.7:1. It wanders. Richens up when you punch the peddle, leans out when you suddenly let off. That's fairly normal, and the same would be acceptable in a hydrogen system.

Also: You could have a hydrogen system that could go from full production to nothing back to full in a milisecond if it was electronic. With ease my friend.

Uh...no. When I hit the gas peddle, there is a slight lag in the air motion, but it is VERY slight. In a carburated engine, the FUEL is the stuff that lags and quick stabs of the throttle result in lean misfire unless a quantity of fuel is squirted in. The engine is operating at a vacuum and there is a large force pushing the air into the cylinders from that vacuum. In a hydrogen generation system, the hydrogen has to be cracked from water. That takes time for the reaction to occur, time to heat the water to allow the reaction to be efficient, time for the partial pressure of the gas in the liquid to build, time for bubbles to form, time for the bubbles to raise to the surface and pop, time for the gas to traverse the distance from the generation system thru the tube to the manifold. That time is in seconds - whole seconds and typically in the 3-10 range depending on the system status. Just put a potentiometer on a system and go from 1 amp to 20 amps and see how long it takes.

The other side of that is also there. You can't instantly STOP hydrogen/oxygen generation. I for one don't want to slam on the brakes and have the engine still supplied with loads of combustible gas + oxygen! Because the quantity of dissolved gas in the reaction fluid would be huge if you had to reach 20%. Sure, a 5% target would be better, but still the issue remains. Naturally, no systems take that into account as they are not capable of generating enough gas.


Speaking of percentages... I thought I made it clear that my numbers were made "easy" to make the math simple. Even at 5% hydrogen a small 4 cylinder engine needs an astronomical volume of gas. While most may spend the majority of the time at 30% throttle, should we ignore the system's requirements for idle ? acceleration ? Higher rpms? I run less than 30% most of the time, but do run 100% on occasion and 50-70% frequently to go from stops or to merge on the freeway.

Your last point was that you can make hydrogen "in a millisecond" by using "electronics". I call BS on that and ask you to provide some factual proof. While I don't know everything, I do know that chemical reactions like this are not digital! And yes, I HAVE diddled around with electrolysis, chemical reactions and even electronics.

Still - I feel I am preaching to the choir as you already have epressed that you don't feel it is a real solution. But, maybe our discussion can keep others from getting scammed.

jb