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Rand Cam Rotary Engine


rudypoochris

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http://www.regtech.com/93.html

 

Does anyone know/own a machine shop that can build this. It runs on diesel, or anyother gas pretty much. They tested a 20:1 compression ration diesel 6" Diameter by 6" long unit that made a whopping 42hp at 7000 rpm, and it gets better consumption then the conventional diesel! What is nice about this is, it is so simple that I think a good machine shop could make one! Plus it is light, and small. They say volumetric efficency is at 30% compared to piston engines 7-8%. This would have to be matted to megasquirt i believe. What do you guys think, good idea for a hybrid?

 

The most difficult part imho, is the the cams, those look tricky to machine.

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WOW, that was a kick in the head...

 

 

...I'm gonna be staring at that animation ALL NIGHT. Thaks alot man! Gosh!

 

I want to know hw those seals work, and if the motor will burn oil like a rotory. I like the idea though. I truly different take on wankle.

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What do you guys think' date=' good idea for a hybrid?

[/quote']

 

No

 

 

 

 

 

But thanks for the link, I thought the quasiturbine was pretty insane but this has beaten it. Also, I dont understand why it doesnt combust at the peak of the hill or whatever, then again I dont really know to much about deisels besides they dont use spark plugs.

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No

 

 

 

 

 

But thanks for the link' date=' I thought the quasiturbine was pretty insane but this has beaten it.[/quote']

 

Hehe i have no dreams of it being reliable, just something to toy around with :).

 

About the combusting at peak, i think they said they use a glow plug to achieve the combustion or a spark plug, not positive though, maybe it is rotating fast enough that the explosion doesn't acctually occur until a few moments after whent he downside of the cam is already under it?

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in a diesel engine the fuel is not put into the cylinder until the compression cycle. this is different for gas motors (yes, even fuel inject ones) where the fuel-air mixture is drawn in together during the intake stroke. so, for diesel operation the simple answer is that they don't inject the fuel until just after the peak.

 

the following is (a little) more about how the diesel engine operates. more written so i can avoid studying for my fluids test in the morning. :ugg:

 

 

in a diesel engine, as mentioned before, the fuel in injected at the peak of the compression stroke. let me break this down by stroke.

 

during the intake stroke, fresh air is drawn into the cylinder.

 

as the piston moves up the bore, compressing the air charge, the change in pressure causes the air to increase in temperature. (remember pv=nrt) so that at the peak of the compression stroke the temperature of the air exceeds the flash point of diesel fuel. the fuel is injected to the hot air charge and it begins to burn (yes, burn, not explode, like our friend gasoline).

 

as the fuel burns the increase in pressure causes the piston to travel down the power stroke... ya da ya da exhaust stroke.

 

some interesting points to note:

 

*the more air the hotter the air charge and quicker the burn, so more air= good. :2thumbs:

 

*there is no such thing as running a diesel lean, power is controlled by altering the amount of fuel injected into the cylinder. with the exception of forced induction or dynamic effects, the air charge is the same at idle as it is at full power.

 

well, i suppose it's time for me to get back to the books...

 

--gabe

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lol i feel like such a dumbass considering that i knew all of that. I just had a brain fart i guess. So yes, the fuel is injected right at the peak compression or right on the downhill slope. I would probably go gas with mine, if i ever had one, which would make it possible to use a carburater to keep things simple.

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Looking at it again, I don't truly understand what makes it actually turn. A mazda/wankle/rotary Has an elongated chamber with 2 different timings offset a little. The initial brun has a directional burn to it that causes it to spin. In thier diagrams it seems almost all the force is just away from the rotor, not actaully perpelling the travel of the rotor.

 

Maybe there's just some small detail i'm missing or they don't show.

 

Wait a second... I just figured it out. They're not burning right at the peak of compression, but after it. AHH, now I understand the conversation about diesel.

 

Ok, so you can't run gasoline in it unless you inject the fuel late, or else you'd had detonation.

 

Is it actually possible to inject enough fuel late enough for high HP use? Or is deisel the only realistic option for the motor, becuase it seems to offer great performance for the weight.

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Well, just had a long conversation with my bro and he's pretty pissed right now.

 

I tried to explain that in this rotary design it's too difficult to use gasoline because it can't take the compression the motor has has, but diesel works becuase diesel is added after the peak of compression. He flat out told me I was arguing to opposites, that I was saying that "they can't use gasoline because it burns to easily but yet doesn't burn easily enough." I tried to explain that the gasoline, if added before compresson, could ignite durnign peak compression, wich would be a bad thing, but if they added it afterwards would need spark pugs wich seems near impossible with the design.

 

He didn't understand and said I was full of BS and need to start looking up my s*** and actually learn something.... I havn't seen him his POed in a long time.

 

I don't know if he's mad becuase what i'm saying really does sound hypocrytical, or if he's mad becuase he can't understand it. Maybe he's just on his man period or something.

 

Can anyone help fix my terms so it makes more sence?

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It can run on gas provided the compression which causes detonation is lowered to below 11:1. Im sure it can run mroe then 11:1 but on 91 octane i don't think anyone would want to push it much more. If normal gasoline was used in this fashion it would be mixed witht he air via efi or carb before entering the intake port. Also a spark would need to be suplied at the combustion point. Diesel simply makes sense on this engine because it is simpler, doesn't require a spark, better mpg, and better volumetric efficency. I wonder, always have, is it possible to inject gasoline into a 20:1 or 25:1 cylinder and expect power? Why don't gas engines run in the same way diesels do? (fuel being injected instead of mixed with the air before)

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Well... Hmm.. good questions. Your last question "fuel being injected instead of mixed with the air before" well, there is direct port injection wich is much better as it can help cool the chamber down using the same amount of fuel.

 

I'd like to see how a diesel fuel burns in a chamber.

 

More on the subject here. It's a GREAT article that I learned alot from. Kinda off topic but it applies in some ways.

 

http://www.streetrodstuff.com/Articles/Engine/Detonation/

 

I think the main differences between gasoline & diesel is it's stability. Gasoline requires much higher temps to burn and burns much faster. Diesel burns slow and easy. Reading the above article I learned for the first time that detonation only happens after the spark. I still don't really understand the phenomina that the pressure from the initial ignite causes the outter fuel to combust creating a secondary flame. When people always talked about tuning a turbo motor until they find the detonation limit, I always had in my mind what I know found out is pre-ignition, wich isn't what they're talking about at all.

 

I've learned alot today, and my head hurts trying to understand it all.

 

Hope you guys like the article.

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I thought diesel needed higher temps to burn, I could be wrong though. But direct injection still requires a spark and can be used at conventional gas car compression ratios. I think maybe the reason they don't inject gas at 20:1 is that, like you said, it may be too sporatic and not even enough.

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Just read this post after being away from HybridZ for 2 weeks. This is very interesting.

 

First thing I thought "this engine will never work because the chamber will never seal." then I thought perhaps the top and bottom of the "free floating chamber divider" can each use 2 pieces of thin free floating metal plate to seal the chamber. The idea is simply borrowed from piston rings in the conventional engine.

 

The main problem in making this in a small shop is the cam surface. You need a special setup or CNC to grind the sin curve.

 

Also I don't think the "volume efficiency" is "volumetric efficiency." "volume efficiency" probably means the size of engine relative to output. This thing is definitely interesting.

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