Plug-in hybrid using hydrogen injection
 

Hello,

Although this is my first post here, I have been casually viewing Ecomodder for some time and realize how controversial hydrogen systems are here. Therefore, I'll preface this post by saying that I absolutely agree with the existing evidence: HHO systems have negligible benefit, if any at all, when they're run off the vehicle's alternator (conservation of energy).

I have come here to bounce an idea off of you more experienced folks that has been kicking around in my head for a while now. I have read several papers (not sure if I'm allowed to link them yet, but I will post their titles below) which indicate without a shadow of a doubt that both HHO and pure H2 can significantly improve fuel efficiency in ICE vehicles. The problem with the existing commercial systems, as you know, is that they all claim to reap these benefits while running straight off the alternator with no adjustments. When used as directed right out of the box, these systems don't seem to confer any improvement whatsoever.

But what if the power for the electrolysis of the water came not from the vehicle's engine, but from a secondary battery charged via wall plug or EV charger? My thinking is that, if a conventional dry cell 12V HHO "water welder" system is instead connected to a pre-charged battery in the trunk and its output is passed into the intake manifold, fuel economy gains might be possible. This would, in effect, allow an ICE to be converted to a PHEV inexpensively and with zero invasive modifications.

So, wise hypermilers, what are your thoughts? I can't be the first person to come up with this idea. Have any of you tried it or something like it?

Eager to hear your opinions.

The papers I mentioned:

1. "Effect of hydroxy (HHO) gas addition on gasoline engine performance and emissions", Alexandria Engineering Journal, 2016, by Mohamed M. EL-Kassaby, Yehia A. Eldrainy, Mohamed E. Khidr, and Kareem I. Khidr.

2. (For diesel engines) "Effect of hydroxy (HHO) gas addition on performance and exhaust emissions in compression ignition engines", International Journal of Hydrogen Energy, 2010, by Ali Can Yilmaz, Erinç
Uludamar, and Kadir Aydin.

3. "A review on analysis of HHO gas in IC engines", Materials Today: Proceedings, 2019, by T.B. Arjun et al.

There are more. Type "HHO" into Google Scholar.

I see it as similar to solar cars. Do you put the cells on the car or on the garage?

The comparsion would be to a system that use 'shore power' to reform the gases and compress them. If the compressed fuel [amendment] weighs less than the seconday battery -- or no.

On the garage. I'm not an electrical engineer, but from the loose figures I've seen for DC electrolysis at 12 or 24 volts, panels on the car for long-term use wouldn't really be practical in terms of weight, required surface area, or output.

For simplicity's sake, let's maybe forget I said anything about solar panels (for now). Just assume I have near-infinite, free 120V power, but don't want to install a proper electric motor, modified alternator, or other existing PHEV system. This is just experimental, after all.

I confuse easily. I thought it was me that brought up solar panels.

I was comparing using whatever-sourced electricty to charge a battery and electolizer, who's weight one might compare to a tank (or two) of compressed gas.

I'm not sure if it's even a good idea to store compressed Brown's gas. Pure Hydrogen requires a tank lined with graphene to avoid loss. Generating it on the fly might be best.

That's also my main motivation for using an onboard battery + generator rather than a storage cylinder. H2 in a properly-sealed tank cannot autoignite... HHO can.

I imagine it would also be significantly less expensive to integrate a mobile generator, and probably more universally legal than carting around a huge cylinder of explosive compressed gas in a civilian vehicle.

Would you capture both gases or just the Hydrogen, and rely on ambient air for combustion?

One could feed the Hydrogen, store the Oxygen, and use it for a booster like NO2 ....or use it to rouse a sleepy driver.

We know hydrogen can improve fuel economy but with best case scenario cost hydrogen costs around 5 times as much as gasoline. The test engines in the studies used quite a bit of hydrogen.
Better off with aero mods.

My thoughts:

By using an external battery you're adding energy to the system from outside, so it will undoubtedly reduce gasoline consumption. Question is whether this is the simplest or most effective method. Consider the extra space and weight a hydrogen electrolyzer takes up, and the efficiency of such a system (~70% cracking the water, ~30% putting it back together in combustion) - you're getting use of around 20% of the energy you put into the battery. And, the amount of energy you can get out of it is limited to how much you can carry in your battery, times the efficiency of the system (20%). There really isn't all that much energy in your typical lead acid car battery.

By comparison, simply offsetting some of the energy generation needed from extremely inefficient alternators (~40% efficient alternator, and ~30% efficient from the gasoline burned, = ~10% efficient use of gasoline) means you're getting almost 50x the "bang for your buck" just using that extra battery you're carrying around to run the car's electronics instead of from the alternator, rather than using it to crack water. Plus you can carry even more battery if you don't have to carry water and an electrolyzer around.

Less efficient than offsetting alternator use, is using that battery to assist in propelling the car through an electric motor. You're still getting ~5x more bang for your buck that way than with electrolysis. However, by hybridizing a car in this way, you also have the other gains of a hybrid system, such as kinetic energy recovery, or the ability to start/stop the engine using electric motor.

Sure, grid-sourced hydrogen can be an improvement, but I think it misses the forest for the trees.

EDIT: Where it COULD make sense, is if you already have excess renewable (free) energy production at home, and you have the inability to sell it back to the grid at a remotely favorable rate or earn credit for it. Assuming you also have the ability to crack water and bottle pressurized hydrogen, using this otherwise excess/waste energy production to create hydrogen to burn in your car is win-win.

This last paragraph captures exactly the spirit of what I'm after. Is it going to be the best option? Absolutely not. Is it going to be a little silly and of questionable commercial value? Sure... but what I want is to know whether or not it will make a significant MPG increase, all other factors be damned.

Now the question is how well this will actually translate when I simply don't have access to the equipment or know-how needed to safely and efficiently bottle my generated hydrogen/HHO.

Regen is a big deal.

Speaking of Japanese Jeeps:

https://blogger.googleusercontent.co...101_092522.jpg
https://justacarguy.blogspot.com/202...-off-road.html

Ideally, I would use an existing water-welder system (i.e. HHO, both H2 and O2) with as few modifications as possible except running it off a separate battery. I know there are ways of electrolytically obtaining pure H2, but those introduce unwanted complexity. My objective here is to make something 100% off-the-shelf and as cheap as possible.

Another fear with pure H2 separation is that, particularly in the mountainous regions that I frequent, the engine would be flooded with hydrogen and starved for oxygen. Not so when the car is making both on its own.

However, this being completely hypothetical at the moment, I'm open to any disagreements or alternative hydrogen-related ideas you can throw at me.

Botting high pressure hydrogen is dangerous and expensive, but assuming you can do it, the gains would be proportional to how much hydrogen you can carry/inject. Most HHO systems amount to a tiny fraction of a percent.

Engineering Explained released a video on hydrogen combustion just a few days ago. IIRC, the conclusion he came to was that, for a very efficient V8, a 60L tank (think large street-side trash bin) filled to 5000PSI with hydrogen would be good for around 60 miles of hydrogen-only range. If you're going half and half with gasoline, you could double your fuel economy for the first 120 miles with a tank just about the size of the rear passenger compartment in most sedans.

With a much more efficient engine, say a Geo Metro 3 cylinder, you could get the same doubling of economy for around 500 miles per hydrogen fill.

Obviously the dynamics are a little different when you're working with pressurized gas, but overall, this is what makes me believe that on-the-fly HHO/H2 generation would be the way to go. Both of the engines that I have available for this project (Subaru FB25 and Honda D16) are relatively efficient four-cylinder designs, the Honda especially so. Further, the gain I'm looking for is nowhere near double efficiency... I'd be satisfied with a 5-10% increase since I'm getting the electricity and water for free.

I'll have a look at that video, thank you very much for the pointer.

The issue with on-the-fly generation is this: Let's say you have a 100w HHO generator. At 20% cracking to combustion efficiency, you're looking at getting 20w of hydrogen out of it. If you're cruising on the highway using 20hp, that works out to around 15000w of energy from gasoline to the wheels. A 100w HHO generator run off a battery thusly should cut around 0.1% fuel consumption. Increase it to 1000w and you're getting 1%.

This all seems solid, but still leaves the question of how the studies I mentioned came to their conclusions using similar methods. Particularly in the first paper, where the HHO generator was of an (albeit optimized to the particular engine) dry-cell plate design and managed to reduce fuel consumption by 34% while connected to the alternator.

Alas, I don't think this will be settled without experimentation.

If they really increased fuel economy by a third then everyone would be using them.

Broadly speaking, every HHO study I've found hasn't actually stood up to rigorous scientific scrutiny. They're generally snake oil.

There are some small benefits, such as hydrogen burning faster than gasoline and allowing slightly less advanced ignition timing, and the extra knock resistance, but from a total system energy perspective they produce 1/5 the energy they consume.

I get you:
If you have a normal ICE car and you want to turn it into a plug in hybrid; efficiency aside, this is probably the easiest way:

You don't need to get the power from an electric motor to the wheels and you don't need to integrate a motor controller with the accelerator and brakes.

Some regen is possible if you have a cutoff valve/solenoid activated by the brakes or a vacuum sensor and a ...'balloon'/reservoir after that in the hydrogen feed line and gear down while slowing.


Efficiency ideas:

The RC aeroplane industry has some very efficient motors that can be modded into alternators. (95+% IIRC)

Electrolyzers are more efficient when a properly set up magnetic field within the cell/s is involved.
There is research proving this and some vids on YouTube.

Pulsed power at certain frequencies also seems to help. Possibly because the pulses set up a magnetic field..?

If you use pulsed DC; use pulsed ~2.1 Volts in a parallel cell;
An open cell is way easier to keep full vs a closed (efficient) series cell, without the efficiency loss.

The exhaust O2 sensors look like they need some fooling or they pick up on excess O2 and the injection system adds fuel..?
In fact you want to run slightly lean and let the HHO 'fix' the arising burn issues.
or
Retard ignition timing slightly, thx to a faster burn..?

Add the HHO after the airflow meter so the system does not add fuel to what is essentially the ideal O to H/fuel ratio already.

According to the science; the most efficient voltage across the HHO cell/s is 1.61 Volts IIRC.
But a voltage of just over 2.1 Volts means some of the O is turned into Ozone (O3) which is good. Both volumetrically and according to a # of studies.
That's probably why tests seem to favour 6 cell (in series) electrolyzers over 7..? (2.2 V per cell vs 1.8)

Engine coolant can be used to quickly heat the HHO cell to a more efficient temperature and then keep it there/cool it.

Using a good old radiator cap on the 'above idea cell' will slightly pressurise it, avoiding any tendency for the electrolyte to boil while at the above more efficient, higher temperature.
That's akin to using a tiny bit waste heat to help produce the HHO. :)

Over thr years we have had several people say "I'll get one to work and show you how" and we never hear back from them. I like to think they died in an hho explosion.

HHO
 

I'd request a complete mathematical representation of the complete energy balance for every stage of the process, beginning to end, illustrating an overall net benefit.
Science is mathematics.
Without quanta we have nothing.

... :) :D lol!
Ye it dosent work.
But fun to think about and tinker with.
And most importantly; fun and easy to do at home, much like pizza pan covers and chloroplast etc aero enhancements.
So, for that reason, it's not going away and shows 'spirit'.

(Perhaps thats why so many engineering students are doing thesis on the subject)

And if people are going to try anyway; then building the system as efficiently as possible is part of the fun, hence my thoughts/ideas above.

I assume you read the OP's 1st post where he talks about producing a beneficial amount of HHO with a home charged battery rather than the car's alternator as a simple means of turning any car into a plug in hybrid??
Then researched the benefit to weight ratios and power costs before coming here to take your usual dump..? :)

Yeah I saw that. The tests used employed bottle fed hydrogen and appear to use far more hydrogen than an hho machine can make.
The one test showed that adding hydrogen improved fuel economy by a third. How do we know they induce a problem and then fake fix it with hydrogen.
The best way I can think of would be to run the engine at low load, at mid range RPMs, retard timing to reduce fuel economy and then add hydrogen because we know hydrogen burns really fast to make it look like the hydrogen increased fuel economy.
Where if the engine was running properly the hydrogen would have only increased fuel economy by a lab measurable amount.

There's no point in H2. Might as well burn the natural gas directly rather than convert it into hydrogen first.

Yep; the "How much HHO can a HHO machine make" is something I keep an eye on. Something like buying a lotto card... :)

There's a whole 'fringe community' online who like to tinker with this.
Here's a new PDF (unread as yet. Looong!) on more or less where they're at:
https://www.academia.edu/21986732/Re...ard=view-paper

That's all Unicorn Corral stuff, most oftten revolving around finding the resonant frequency/ies that blast H2O to bits with very little power.
Light s also also in their conversations and some proper research on light as a catalyst is available.
Lets hope someone gets it right and it's reproducible... and doesn't 'disappear'.

Yep there are ways to cheat.
And often employed by people trying to sell crappy, open cell, serial HHO cells:

• Boil the electrolyte to get big bubbles, either by running the cell hot or pulling a vacuum on it.
• Use huge amounts of power/voltage.
• Mess with the initial ignition timing etc.

But a lot of the studies are done by engineering students to get their thesis/degree.
These people don't stand to benefit financially and would get their degree whether the experiment showed an advantage or not.
So no reason to cheat..?

Many of them do show benefit. Even from a alternator run cell.
If one goes by the # that do vs those that don't; things remain interesting, but not interesting enough to tinker with unless you have 'school fee' money to burn. :)

Personally I feel that using the waste heat (exhaust mostly) to produce a fuel or add value/energy to it is most interesting.
I note that Syngas, is commercially produced at temperatures below those of a std car exhaust.
(Imagine being able to substitute 75 to 90% of your fuel with water! :) )

But the pressures used for optimal H2 production are dangerously high and would add much weight to a car.
Then there's the fact the the added heat for the reaction isn't in the "6 to 9 parts water to one part fuel" equation and takes fuel somewhere.

But what if the enough Syngas/H2 can be easily produced (lower pressure) to actually run lean or retard timing, ..?? :)
The remainder of the gassified fuel remains fuel and the steam, steam.
Both show advantages in ICEs..?

MIT's Plasma Fuel Reformer was headed in this directoin before dropping off the map.
I 'heard' it was bought out and shelved..?
https://www.greencarcongress.com/200...eritor_cl.html

Adding some moisture to the intake charge may actually be beneficial under some circumstances, be it droplets or steam which is what some so-called HHO kits actually provide, but HHO is mostly either pointless or a placebo. Were you resorting to an auxiliary electric motor or an electric pusher-trailer, powered by the batteries charged on the grid, it would eventually be more reasonable, as the efficiency of an electric motor can still be much higher than the electrolysis in an HHO cell.