06-24-2008, 06:21 PM
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#41 (permalink)
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Harebrained Idea Skeptic
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Quote:
Originally Posted by ttoyoda
If my impression is correct, then it seems an engine ECU would be (almost???) un-needed, you could just have a box that pulse-width-modulated the injectors, and the control knob to set the duty cycle would be attached to the gas pedal. There would be no need to synchronize the fuel injection timing like is needed on a diesel engine.
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If the point is to maximize efficiency, you would want an ECU in order to have sequential injection phased properly to the intake timing. Otherwise, you'd have to resort to batch or bank injection and would have the injectors firing at closed valves most of the time.
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06-24-2008, 06:28 PM
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#42 (permalink)
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EcoModding Lurker
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ttoyoda, It seems that you are correct in your assumptions. In practice, I don't know how exactly it would all work out. The removal of the throttle body is possible because of the huge range of air concentrations in which hydrogen can burn. Gasoline is quite narrow. The full DVD goes into alot of this.
There are also some big drawbacks to a full h2 (or h2 hybrid) conversion because h2 is still hard to come by. Unless you have a solar hydrogen generator in your backyard or access to h2 filling station it is hard to justify all the work. That is why I want to do an h2 assist setup because it can be changed to run on 100% gasoline very easily.
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06-24-2008, 06:32 PM
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#43 (permalink)
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Master EcoModder
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Quote:
If the point is to maximize efficiency, you would want an ECU in order to have sequential injection phased properly to the intake timing. Otherwise, you'd have to resort to batch or bank injection and would have the injectors firing at closed valves most of the time.
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Well that is how my cars work now, all the injectors fire at the same time once per revolution according to the service manual. For a first test it would be fine, and the simpler the first test the better.
However, the control box could take one trigger input from the camshaft and extrapolate the rest from engine rpm, (or 4 trigger inputs for 4 injectors) to fire the injector at the "right" time. I think it a lot easier to build a control box than to "fool" the original car ECU into doing what is wanted here. In fact a test could use an old single point throttle body with the butterfly valve removed.
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06-24-2008, 08:53 PM
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#44 (permalink)
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Steady as she goes
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Quote:
Originally Posted by Shawn D.
-- That analogy only shows that one can come up with poor analogies that don't prove anything.
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I thought I explained myself clearly in the post I submtted immediately after I wrote that statement.....I guess not
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06-24-2008, 09:24 PM
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#45 (permalink)
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We should be clear that 'HHO' is an (incorrect) term referring to oxyhydrogen, hydrogen and oxygen, aka "Brown's gas" when it's produced in an electrolyser with a single duct (ie, no seperation). Oxyhydrogen is "easier" to produce than hydrogen, thus it's false to simply apply the same "hydrogen generation is waay too energy intensive" logic to an 'HHO mod'.
So HHO shouldn't be referred to as 'hydrogen injection', and not put in the same basket as nitrous oxide injection... although after more experimentation we might discover that the oxyhydrogen is really just an oxidising agent after all, hahah.
@ttoyoda, yeah the atomised fuel/air is sucked in when the valve opens, not real important when the injector fires. Just look how long the cloud of fuel/air hangs around in the intake on a carb engine.
I imagine injecting at precisely the right time would reduce the chance/effect of a lean backfire, but that's another issue.
I don't think I understand how you could remove the butterfly with an HHO mod though? Is a pulse width modulator acting as the throttle?
For a mod'd petrol engine or a hypothetical fully converted HHO engine?
On the fordmods forum you'll see a pattern of people building an HHO kit from whatever they have laying around, chucking it in their car with little consideration, and getting improvements, I haven't seen anyone there tricking ECUs or leaning mixtures yet.
Only 3 days until the weekend; I'll try to build mine then :-)
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06-24-2008, 09:29 PM
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#46 (permalink)
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Steady as she goes
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SilverNight, Thanks for the great info ! What kind if car are you putting your HHO set up on? And do you have an idea of how much H2 you will be generating ? Or is there a chart on how much can be generated by plate size, water volume, amount of electricity etc?
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06-24-2008, 09:33 PM
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#47 (permalink)
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06-24-2008, 09:38 PM
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#48 (permalink)
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EcoModding Lurker
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Quote:
Originally Posted by RacerX
SilverNight, Thanks for the great info ! What kind if car are you putting your HHO set up on? And do you have an idea of how much H2 you will be generating ? Or is there a chart on how much can be generated by plate size, water volume, amount of electricity etc?
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I will be putting it on my 96 Integra, the one in my sig.
I dont know how much HHO I will be producing quite yet. I am trying to figure out the best way for me to make it efficiently. At think point I know I will not be close enough to the 5% mark to drastically change my timing and whatnot. There probably are charts but there are too many variables to calculate so I will be testing the output of my cells before installing on the car. I might mess with different designs if i see promising results from version 1. (Technically v2 because cell v1 didnt produce much and had some design flaws.)
Quote:
Originally Posted by JamesLaugesen
I don't think I understand how you could remove the butterfly with an HHO mod though?
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You can remove it because your overall fuel burn is burning like hydrogen so you throttle your fuel, not air like the throttle body does. With H2 you have more stoichiometric range, so to speak.
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06-24-2008, 09:40 PM
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#49 (permalink)
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Master EcoModder
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Quote:
I don't think I understand how you could remove the butterfly with an HHO mod though? Is a pulse width modulator acting as the throttle?
For a mod'd petrol engine or a hypothetical fully converted HHO engine?
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Yes pulse width modulator as throttle, for a modded petrol engine.
But I think it might need more hydrogen flow than a generator can provide, I don't know.
My theory comes from watching that series of youtube videos I linked earlier. In one of the videos, they run a small 5hp horizontal shaft engine that has had the carb completly removed. There is no air control at all.
They insert a thin hollow tube into the hole where the carb used to bolt up, and place the tube so it is far inside the hole, close to the intake valve. They blow hydrogen down this tube. They are able to start, idle, and run the engine at varying speed by ONLY increasing or decreasing the flow of hydrogen from a tank.
So my theory is, you could remove any air control on a car engine (like the butterfly valve in a throttle body, I guess you need the throttle body just to hook up the air filter easily). Then you add just enough hydrogen all the time so the engine just idles (with no air control mind you). Now you add gas from the injectors to increase/control the engine speed.
I really suggest you watch the whole series of videos. It is pretty amazing to see a spark ignition engine run with no air control.
silverknight has some good posts earlier in the thread, he has posted while I have been previewing mine.
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06-24-2008, 09:46 PM
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#50 (permalink)
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Master EcoModder
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ihatejoefitz,
First of all, why?
Second, could you please watch those youtube videos and give us your University of Kansas engineering opinion?
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