Hamza734

Bullshit. Where does the energy for the batteries come from? High output batteries already exist. Our trust IC engine ain't ready for the scrap heap yet.

peejay

The rotors AREN'T geared. They drive the E-shaft directly.

The gears that are there are *timing* gears, to ensure that the rotors don't hit the rotor housings.

Hamza734

Larger diameter pistons will make the engine spin faster (i.e. horsepower). Longer strokes give the torque. Besides, the empirical evidence backs this up:

Motorcycle engines: very oversquare-high RPM, high HP but low peak torque.

Truck Engines: typically undersquare, lower revving but considerably more torque.

Hamza734

I agree that future stationary gears will have more teeth. More teeth adds further precision to the rotor timing and be stronger (reduced shock loading on individual teeth).

peejay

Larger diameter pistons don't "make" the engine spin faster but they do allow for lower forces on the piston and rod for a given displacement and engine speed, and they allow for more valve area to be fit into the combustion chamber.

Now chew on this... for a given displacement, and identical sized valves, a longer stroke will require ports that flow better.

PDF

How many of you know that enough hydrogen to run an engine can be made in the vehicle, by using the 12v system to produce hydrogen from water. It is very cheap and easy to do, there are a couple of daily drivers I know of running this way. I have got an engine to fire up but poor choice of material caused the water container or "cell" as you might call it, to suck in under vacuum, breaking the seal an causing the mixture to lean out. Due to lack of time I have yet to carry on with it.

The reason hydrogen 'storage' is being developed is for oil companies to make money from hydrogen they first need to make it so they can then distribute (sell) it at outlets. But then ofcourse they are not going to tell people it can be easily made in-car using water because they will make 0 dollars out of this

An point of interest, when 12v is put through the electrode/s submerged in water hydrogen bubbles are formed and rise to the top(simple chemistry) but as soon as a vacuum is introduced they form many times faster.

peejay

Only problem with that is that you use a LOT of energy to separate the hydrogen from the oxygen, and you don't get it all back when you recombine them (burn the hydrogen). It would be more efficient to just use the 12v system to drive an electric motor.

Remember, you can't win (can't get something for nothing - the energy you generate has to come from somewhere). You can't break even (you don't generate as much energy from a reaction as was originally used to "store" the energy).

In other words, using the electrical system to disassociate water into hydrogen and oxygen, so you can recombine them back into water, will not generate enough power to move a car. It won't even generate enough power to recharge the battery that is being used to disassociate the water.

This is why the best ideas for hydrogen powered cars generate the hydrogen in-car by removing the hydrogen from gasoline or other hydrocarbon chemicals... there is a lot of energy stored in HC's.

projekt

this is often not the case however. if the motor is naturally a stroker you'd want ports that flow worse (within reason) but with an increased velocity.

KevinK2

I read and thought.

Internal gearing means 3 revs to fire all 6 chambers. to compare low end torque look at 2.6L 4 hole boinger ... square. Both fire 2 chambers per rev. For boinger, bore = stroke = 3.7", so crank lever for torque is 1.85".

13B has .6" crank lever, and 3e effective stroke, and 22.08 sq-in piston area. Peak instant torque is P x 22.08 x .6 =13.2P, where P is a reduced pressure where rotor face is square to the e-shaft offset., for each chamber.

For boinger, peak instant torque is P x 10.7 sq-in x 1.3 x 1.85 = 25.8P, or 2x the 13B, assuming similar reduced P. The 1.3 relates to higher rod load vs piston load due to angle .... inherent force multiplier.

Cam timing does contribute, but a .6" lever arm is main reason for low torque, per rev.

andrew lohaus

actualy you do get baisicaly 100% back due to the laws of chemical kinetics; however, the means for harnessing that re-released energy arent 100% efficient so you will still be at some loss on the end.

dont kid yourself that this only applies to hydrogen tho.

the best IC engines can only render about 30% of the energy in the feul into useable power. IIRC feul cells are 50%+ efficient.

regardless, hydrogen at most will serve as a few decade bandaid for the much larger problem that the world only has so much fossil feul left, so long as it is primarily derived from HCs.

i see the only viable solutions as either nuclear power and/or renuable power. batteries or feul cells serving as the means of storing that energy for use in automobiles. however battereis will likely prove more effecient than feul cells, but econimcs will end up picking in the end for which one is cheaper.

my .02

Hamza734

You can NEVER get back 100% of what you started with. It's the Second Law of Thermodynamics, which has never once been disproved...it's also why there's no such thing as a perpetual motion machine.

Also, the concept of a Hydrogen economy is not a band aid. 98% of the universe is hydrogen. Copnsequently, we have an essentially inexhaustible supply. The real problem with hydrogen is that electrolysis (splitting water molecules into hydrogen and oxygen) requires more energy then there is inherent in the hydrogen. This might seem like an insurmonatable issue, but it really isn't. If the infrastructure devoted to extracting petroleum, was wholly turned over to hydrogen production, it would be a lot more viable economically.

Also, renewable energy sources (i.e. solar power in the mideast, wind power off the ocean coast etc...) could be devoted to hydrogen production. Over time, I think it'll happen.

-h-

http://people.howstuffworks.com/hydrogen-economy.htm

peejay

Of course it doesn't. However, the fuels we use benefit from having the energy already stored in them... in the case of methanol/ethanol, the energy of the sun is harnessed by plants to convert basic elements/molecules into sugars, which are then fermented (sugars digested by another life form and excreted) into alcohol. There's a good deal of stored energy in the alcohol, which is why it makes such a pretty bang when you combine it with oxygen - you get that energy back. No we don't get to keep *all* of it but we get enough to motivate a vehicle.

Note that energy was *used* to create the alcohol, that energy more-or-less came from the sun. As does practically *all* of the energy we use to one extent or another, excepting nuclear power, which is so far removed that it doesn't really count for these purposes.

Gasoline is the same way... the energy is "stored" into the molecule, we extract it by burning it (combining with oxygen). If we had a machine to take carbon dioxide and water and separate them and reassemble it as hydrocarbons and oxygen, it would require more energy than we would get from burning the HCs in the first place.

AREITU

I predict that the majority of people will not appreciate the engine and that one day, all rotaries will be replaced by a V8.

Sad, ain't it?

OneRotor

iTrader: (3)

torque is not force on a lever, it's rotational force. you put torque on a screwdriver when you turn it, you get torque by a boinger pushing down on the crankshaft or the rotary spinning the EC. also, torque is used throughout the powerband. horsepower is just high-end torque, because it's rotational force.

OneRotor

iTrader: (3)

about the hydrogen rotary idea. the vast majority of hydrogen is not derived from crude oil, it's extracted from natural gas. the major problem with gasoline vs. hydrogen is this: per mole (6.02 x 10^23 atoms), hydrogen puts out a hell of a lot less energy than gasoline. i can't find it in my chemistry book right now, but gas is much more dense as far as power potential than hydrogen is. this is why natural aspirated hydrogen rotaries are nowhere near as powerful as a gasoline rotary. to the best of my knowledge no one has made a forced induction hydrogen rotary engine, but even if they did, the gasoline equivalent would be a ton more powerful. if memory serves me right, the hydrogen RX-8 had something between 70 and 110 horsepower, down from the 238 of the gasoline variant. the gasoline equivalent is over two times more powerful. there is a group in New Zeland (http://www.monito.com/wankel/hydrogen.html) there is their site, is working on using a tiny amount of hydrogen to heat up the combustion chamber, and just after the hydrogen is ignited, water is injected, vaporizes, and gives the engine it's power. the reason why hydrogen isn't used in boingers is that it burns extremely hot, on the order of 1500 degrees F. such high combustion temperatures warp normal valves and cause them to snap off in the cylinders. the valves would have to be made out of some exotic material like Tungsten (it's the element with the highest MP known to man). this is why people are looking toward rotaries to use as a hydrogen ICE. in a rotary, if you spark a little hydrogen, use it to heat up the combustion chamber to over 1000 degrees F and then inject the water, the effect will be two fold: one, it will instantly cool the chamber as the water is vaporized so you don't have a problem with warping housings, and secondly since anything that goes from a liquid state to a gas state will expand to roughly 1000 times it's original size, it will put tremendous force on the rotor, thus making alot of power and making for the power disadvantage caused by using hydrogen as a fuel.

OneRotor

iTrader: (3)

now onto the notion of a diesel rotary engine. whoever said earlier in this post that diesels run somewhere on the order of 20:1 compression ratio is absolutely right. i'll use the old 7.3 liter Ford Power Stroke Diesel, because i remember the specs right off hand from the auto show a couple of years ago. the compression ratio was 18:1 or 18.5:1, and it was running upwards of 30 psi max. boost. now, even if someone could figure out how to get that high of a compression ratio in a rotary engine, there is no way that any apex seal would ever stand up to that high of a compression ratio plus over 30 pounds of boost. a diesel rotary is just not a viable solution.

Hamza734

Diesel rotary has been done-SEVERAL times. Provided there's no detotantion or pre-ignition, the apex seal will be fine. There's a NASA research paper from the early eighties about high-compression rotary engines. There's a great quote, something to the effect that:

"the unthrottled rotary engine is the only stratified charge engine variation which can operate as lean as a diesel, and achieve automotive diesel fuel efficiency levels."

Hamza734

There's no engine that uses hydrogen, then water to generate power. From a physics and engineering standpoint, this is impossible. I think your confusing pilot hydrogen injection. Here, a tiny bit of hydrogen is injected slightly in-front of the spark-plug. The effect is that the combustion occurs much faster. The idea is that you can use a much leaner A/F ratio, and therefore achieve greater efficiency. Hydrogen does have less heat energy then gasoline or other fossil fuels. But, it has two huge advantages:

1. Limitless supply (98% of the universe!)
2. Relatively Clean Burning. It produces some oxides of nitrogen, but little else.

Only real problem is that it takes more energy to create hydrogen (electrolysis) then there is inherent in the hydrogen.

OneRotor

iTrader: (3)

did you even look at the link? the group in New Zeland has a hydrogen rotary engine that uses water injection after the combustion has started. it is a very feasable idea. i'll search for the stuff in my chemistry book about the power potential of hydrogen vs. gasoline. i'll retract my statement about the diesel rotary engine, because i havn't done much research on it, but all of the other stuff, i'm either A. quoting a website that was put up by the people who got the hydrogen and water rotary engine running, or 2. quoting my chemistry book. i've had 2 semesters of chemistry at michigan technological university, i'm finishing out my second right now, so do some research and get back to me on your findings before you try and disprove something i said. you disproved me with the diesel rotary with the quote from the NASA paper, now disprove me with the other two statements with facts, not your or anyone else's opinion. now, about the energy needed to make hydrogen. you don't need to use electrolysis to make hydrogen. this may be the easiest way to make hydrogen on a personal budget, but there are other ways to make hydrogen alot easier and with less energy. here is one site that has a really easy way to produce hydrogen out of an aqueous solution of Sodium Borohydride (NaBH4) and Sodium Hydroxide (NaOH), and a catalyst is used to make the reaction occur. this solution is stable and non-flammable. the website is: http://www.millenniumcell.com/index.pl
here is another site about making hydrogen without electrolysis: http://www.powerball.net/

OneRotor

iTrader: (3)

and one more thing (sorry about the second post, it took me a few to dig up those websites and the information in my above post).

the water injection is impossible from an engineering and physics standpoint? are you an engineer? or a physicist? if so, then what principals are you basing your reasoning on? according to Newton's Third Law of Motion, every action has an equal and opposite reaction. if you start the combustion process, and you burn just enough hydrogen to superheat the chamber for a split second, this will keep the rotor spinning around in the housing. when you inject the water, as long as you inject it at a high enough pressure, it will come out as an extremely fine mist, which will instantly vaporize and increase the pressure in the chamber, which in turn will push the rotor with more force, creating more power. disprove me with facts and research that i can't disprove through more research, and i'll retract this statement. if you have figured out that this statement by Newton is incorrect, show the world your findings and you'll win the Nobel Prize in Physics!!!!

with the above link, the place that you want to look is at the bottom of the page, or click this link: http://www.eskimo.com/~ghawk/rotary.html

OneRotor

iTrader: (3)

WOO HOO!!! finally, someone is using logic and researching to disprove people, not just shooting off their mouth with their opinion. he's completely right, there is a ton of energy stored in hydrocarbons. right now, methanol and gasoline are the two fuels that companies are looking at deriving hydrogen from, but the biggest problem they are having is making a fuel cell out of reasonable-priced materials that can use the hydrogen from this process. the hydrogen is not 100% pure, and the impurities cannot be put through cheaper fuel cells because they will destroy the fuel cell, this is why companies are looking at alternatives. right now, the most feasable way to use hydrogen in a fuel cell is through a on-board tank that uses a metal hydride to store fuel. the link in my post above that goes to monito.com has information about it. they are also looking at powerballs (powerball.net, also in an above post) and millenium cell (http://www.millenniumcell.com/index.pl, also in an above post) are the two that are most likely to be used in the first production fuel cell cars.

Hamza734

Yeah, VERY impressive. Naturally your 1 year of schooling qualifies you to speak as an expert. I have a bachelors degree in Mechanical Engineering from the University of Michigan, Ann Arbor. I'll soon be working towards my Masters. Done coursework in chemistry, thermodynamics, combustion, IC Engines, vehicle dynamics and automotive engineering.

Of course their's more then one way to create hydrogen. However, from a commercial standpoint, the cheapest/easiest way to do accomplish some task is how its done. PERIOD.

Again, a marvellous argument. What exactly does Newton's First Law have to do with this discussion? NOTHING.

Utter bullshit. Take a moment and re-read what you wrote. There's a not a shred of truth to it. Your confusing water-injection into gasoline IC engines (for example into turbocharged motors) with something else. A quick look through my IC engine and thermo textooks reviled nothing about a water-powered engine. I could spend more time picking apart your arguments but its getting late and this old devil-dog needs his rest.

OneRotor

iTrader: (3)

larger bore boingers are more associated with torque. larger pistons equal more reciprocating weight, so that means lower rpm's. that, and rpm's aren't really determined by the diameter of the piston. they are determined by the valvetrain (how high is the valve spring's tension rated, the timing), and how strong the con-rod is. plus, high rpm engines normally have a short stroke, which gives them less torque (which you stated with the: "longer strokes give the torque" arguement)

MikeC

Hi Kevin,

I get 1.5, not 2. If you have a pressure P in the chamber at the point of peak leverage you get Torque = 15mm x P x Area. If you take a piston motor with the same piston surface area you get a stroke of 45mm, so an effective leverage of 22.5mms. So T = 22.5 x P x Area. Pressure and area are the same so the only difference is 22.5 vs 15, which is a ratio of 1.5. This ties in with the 3e effective stroke, the rotary produces 1.5 times less torque over 1.5 times greater distance so the same amount of energy is transferred from the compressed gas to the shaft.

The above calculation works for any bore/stroke that gives a 654cc swept volume but it is easier to assume the surface area is the same so that it can be eliminated.

MikeC

The rotors are not geared, the output shaft is. If a piston goes from TDC to BDC to output shaft goes around 180*. If a chamber in a rotary goes from TDC to BDC the output shaft goes through 270*, an effective gearing of 1.5 times. It is not as simple as just a gear on the drive shaft but it is the same affect, the gears in the rotor lead to this ratio.