New idea, any help
03-30-09, 11:56 PM
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New idea, any help
Ok so last year a friend and I started messing around with hydrogen cells and we are able to make a fair bit of hydrogen. Since hydrogen is highly explosive it should be able to be used to run an engine. The problem we had before is that the engines we used were fuel injected and computer controlled and so when the ECU noted more air it would dump more fuel in to keep the air/fuel mixture constant. I have a 1980 RX7 which is carbureted and so there will be no computer interference. What I am wanting to know is if it is possible to cut off the flow of fuel to one of my rotors. I am hoping to make one run on gas and the other run on hydrogen, if I can do that then at least I'll know it'll work possibly on both. Does anyone know of any way to cut the flow of fuel to one rotor, preferably just in the carb?
03-31-09, 12:19 AM
#2
Wrkn Toyota, Rootn Wankel
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While the hydrogen powered rotary has been done already. (Search for the Hydrogen RX8 in Japan.)
The problem with your idea is simply that you want to run two different fuels in rotors that are on the same shaft. You might run the risk of detonation or what not and causing a decrease in performance of the engine. I would suggesting using a stock 12a and using a second one to bench test your idea.
The problem with your idea is simply that you want to run two different fuels in rotors that are on the same shaft. You might run the risk of detonation or what not and causing a decrease in performance of the engine. I would suggesting using a stock 12a and using a second one to bench test your idea.
03-31-09, 01:04 AM
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if you pull the hydrogen through a vacuum, you can increase efficiency. or so says a recent thread.
https://www.rx7club.com/canadian-forum-42/hydrogen-boosting-my-7-seems-work-just-fine-768614/
because like he said, you run the risk of detonation. which is bad.
https://www.rx7club.com/canadian-forum-42/hydrogen-boosting-my-7-seems-work-just-fine-768614/
because like he said, you run the risk of detonation. which is bad.
03-31-09, 09:36 AM
#4
It'd be a lot easier to test your theories on something simpler, like a lawn mower engine. One cylinder, smaller demand, and a lot less expensive if something goes wrong. If you cna make it work on a single-cyl engine, you can scale up easily enough.
Trying to "split" the rotary to be fuelled differently on each rotor is probably an unnecessary complication, and risks all sorts of bad & expensive side effects. With a stock carb, it's likely far more work than it's worth, as you can't decouple the throttle plates to get different rates for each cylinder.
At a minimum, you'd want to go with a dual-carb split intake, so you can properly balance between the HUGE mixture differential between gasoline and hydrogen. On the hydrogen side, you'd not want a real carb in any case (no use for a bowl and float mechanism), you'd want fuel injection, since you are mixing two gasses, rather thana gas and a liquid.
You're going to need a LOT of hydrogen. Probably a lot more than you realize. Its density is so low that you'll have to deliver it at far above atmo pressure in order to get enough energy from the combustion to run the engine.
Trying to "split" the rotary to be fuelled differently on each rotor is probably an unnecessary complication, and risks all sorts of bad & expensive side effects. With a stock carb, it's likely far more work than it's worth, as you can't decouple the throttle plates to get different rates for each cylinder.
At a minimum, you'd want to go with a dual-carb split intake, so you can properly balance between the HUGE mixture differential between gasoline and hydrogen. On the hydrogen side, you'd not want a real carb in any case (no use for a bowl and float mechanism), you'd want fuel injection, since you are mixing two gasses, rather thana gas and a liquid.
You're going to need a LOT of hydrogen. Probably a lot more than you realize. Its density is so low that you'll have to deliver it at far above atmo pressure in order to get enough energy from the combustion to run the engine.
03-31-09, 01:26 PM
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I think playing with both fuels at once is a recipe for disaster. You could kill yourself.
If you're hell-bent on trying that, then two differnt carbs is the only way to go, with complete separation (no plenum manifold). The left & right side main circuits in the stock carb share ventilation, etc, so depite all efforts, you'll get cross contamination. Though I love chemistry, I really have no idea what could happen, save to say it's a safe assumption that it can't be good.
I think you should definitely persue this, as I like to seem more people experimenting with alternative fuels in rotaries, just not that way is all.
Maybe a one rotor snowmobile engine to start with?
If you're hell-bent on trying that, then two differnt carbs is the only way to go, with complete separation (no plenum manifold). The left & right side main circuits in the stock carb share ventilation, etc, so depite all efforts, you'll get cross contamination. Though I love chemistry, I really have no idea what could happen, save to say it's a safe assumption that it can't be good.
I think you should definitely persue this, as I like to seem more people experimenting with alternative fuels in rotaries, just not that way is all.
Maybe a one rotor snowmobile engine to start with?
03-31-09, 01:29 PM
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We have used a small 3hp Briggs and Strattion pump motor and were able to get it running for a short time but had issues with loosing too much hydrogen. Because a conventional engine needs both fuel and air you loose some hydrogen through what ever line you aren't pumping it into.
Ok so here is what I was thinking, I'm likely a long way (if it's even possible) from a stand alone hydrogen system. Since the 20b has three rotors and there are others that have 4 (concepts) shouldn't it be able to run on one? if I can cut the fuel off to one rotor it should still run just with a lot less power and it'd be less smooth. So if I can drive on one and then there becomes a difference when I hook up the hydrogen then I'll konw there is a difference. I hope to possibly in the future just store up an amount of hydrogen and then release it on demand, much like NOS. youtube has videos of people who have done this but not on a rotary.
Ok so here is what I was thinking, I'm likely a long way (if it's even possible) from a stand alone hydrogen system. Since the 20b has three rotors and there are others that have 4 (concepts) shouldn't it be able to run on one? if I can cut the fuel off to one rotor it should still run just with a lot less power and it'd be less smooth. So if I can drive on one and then there becomes a difference when I hook up the hydrogen then I'll konw there is a difference. I hope to possibly in the future just store up an amount of hydrogen and then release it on demand, much like NOS. youtube has videos of people who have done this but not on a rotary.
03-31-09, 03:06 PM
#7
That's why direct in-cylinder (or in-chamber) fuel injection is the way to go; you can do your injection under pressure (again, it'll need to be, to get enough hydrogen mass to generate enough power) after the intake closes off airflow. Bingo, no more "reverse flow" problems. Rotaries are just like 4-stroke conventional engines with regard to their need for fuel and air, and even though they don't have valves, their porting works just the same. Feeding via vacuum (normal aspiration) will suffer from the pressure-differential problem.
If you just try to spray it down the carb neck like nos, you're not going to get enough hydrogen in to make a difference, much less to run exclusively on it; hydrogen is LIGHT!
A 2-rotor engine running on only one is a very wimpy beast; mechanical losses eat up so much of your power, at just the wrong part of the stroke cycle. A 3-rotor running on 2 would be better, but if you've got 20B money to toss around, you may as well just do a full-up 100%hydrogen conversion. Simpler, maybe even cheaper.
Interesting ideas, though.
If you just try to spray it down the carb neck like nos, you're not going to get enough hydrogen in to make a difference, much less to run exclusively on it; hydrogen is LIGHT!
A 2-rotor engine running on only one is a very wimpy beast; mechanical losses eat up so much of your power, at just the wrong part of the stroke cycle. A 3-rotor running on 2 would be better, but if you've got 20B money to toss around, you may as well just do a full-up 100%hydrogen conversion. Simpler, maybe even cheaper.
Interesting ideas, though.
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