I found it rather interesting.

http://www.memagazine.org/backissues...input_out.html

I'm gonna go play with my kid's toys now that I have an excuse.

 

sounds interesting, but i guess i'm having a hrd time seeing the big picture on how it works. same goes for radial aircraft engines, which is sort of what this sounded like or even a flat engine like VW or corvairs.

 

This is the way I understand how the piston would move up and down only because I played with my sister's Spirograph when I was a kid.

I have no idea how they'll get the engine to drive anything, but that's their job.

I drew this picture that kinda shows how a the Spirograph did this, because I was also facinated with it when I was younger. Which is why it stayed in my mind.

BTW, imagine these circles having teeth on them. I'm not gonna draw those.

The red ring is fixed. The gray gear "spins" inside of it. Hence the planetary gear. If you put your pencil in the hole (black dot) you get a line like the green one. The motion of the pencil stays linear.

I imagine they would use a wrist pin similar to the one in the pistons we use now, and attach it where the pencil would be.

How they get it to drive any output shaft would probably be done with other gears??? I haven't put that much thought into it.

 

They obviously have gone through all that if they have a working prototype. Sounds like it was single-cylinder, though.

How it works: Rotate the red ring. The grey gear rotates. The "pencil" is allowed to go up and down only, so that will drive the piston up & down. Once you have "ignition", the motion of the "pencil" will turn the grey gear, which will rotate the red ring.

The red ring could be what we call the "crankshaft". Think of an automatic tranny planetary hub.

 

I understand that, which is kinda how I figured they did it, but there's a problem I see.

How would they use multiple pistons? If the red ring also moves, then you would only be able to have one piston/rod on the end. Try to add more pistons like an inline 4 cylinder, and the red gear couldn't be a "tube" persay. Otherwise there would be no exit for the connecting rods, right?

You could have opposing pistons, which is what I think ede was getting to, but that would limit you to two.

Am I right in my thinking?

 

way cool! I think this is really cool where inspiration comes sometimes!

 

Perhaps that's why they mentioned 4 cylinders. The output would be a gear or sprocket & chain in the middle.

 

Put teeth on the inside AND outside of the red gear, then you could drive a secondary shaft and have as many cylinders as you want.

 

score one for american automotive engineering:hail:

 

I hear that brother

 

Four pistons can be attached to one planetary ring in a horizontally opposed arrangement. It isn't a significant departure from the single rod journal in a nine-cylinder radial engine. Well, I guess it is to some extent, but not as much as one might initially think. Interesting, at least.

 

Here's another odd one that's been around for quite a while - A diesel radial aviation engine:

http://www.zoche.de/specs.html

 

Another thread with the same topic: https://www.thirdgen.org/techbb2/sho...hreadid=220258

I found a good site showing what happens in the planetary gears.

http://ajs.net/spirograph.htm

Set the moving gear to half the size of the fixed grear and watch.
When offset is 0 you get a perfect line.

It should even be possible to make the piston and rod as a single unit. Then the skirts could also be removed from the piston making it lighter because the rod would locate it square in the cylinder bore. With the piston skirts removed the 'rod' can be shorter without the piston to crank clearance problems. The cylinder head will be closer to the crank center for an engine with the same stroke making it more compact.

The 'flying' cylinder heads are the size of the conventional engine.

A 'normal' crank would be connected to the center of the planetary gear.

 

WRONG!

The red ring is stationary and the grey is the only one moving.

 

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Look at this again: http://ajs.net/spirograph.htm

Use then following settings:

fixed gear = 60
moving gear = 30
offset = 0

Then Click [draw]

The fixed gear will be fixed, like bolted to the crankkase.

There will be a bearing at the center on the moving gear that connects to a normal crankshaft. Note that it is a perfect circular motion.

There will also be a bearing at the edge of the moving gear that connects to the piston rod. In this example the cylinder will be on one side. Note the perfekt linear motion.

Now look at this picture I made again:

 

A one cylinder engine is easy.

A two cylinder boxer engine is just as easy. Both pistons and the connecting rod could even be cast as one solid piece.

It is not possible to make a 'star' or V engine with many cylinders in different angles as the it is a linear motion in one direction only. If you add more connecting rods to the same moving gear then they will interfear with each other.

It is possible to stack many one cylinder or boxer pairs using gears, but you can not have a solid crankshaft thru the engine line a normal inline or V engine.

 

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It is a java applet. It works for me but takes a few seconds to load

 

http://www.wisemanengine.com

 

What I don't like is here:

http://www.wisemanengine.com/testing.htm

It has no mention of power output. I could compare a Honda engine to a poorly built small block. Sure the Honda consumes less oil, runs cooler and smoother etc. but that doesn't mean that that Honda engine makes anywhere near as much power as the small block. Without the power, it's tough to make a comparison of apples to apples. If it does make crappy power, I can definately see using it in a hybrid application in conjunction with an electric motor for amazing fuel economy. If it does make equivalent/more power, crap, sign me up

 

http://www.wisemanengine.com/graphs.htm

 

I still don't like how they don't show torque curves per RPM, i.e. a frickin' dyno run, but point made

 

I could see how you could make a V8 with that design.

The red gear in AJ's drawing will be stationary. The grey one will be attached to a "crank" of sorts that spins on a bearing. With it designed like that you could run an unlimited about of cyl's either inline OR V-style. I think it's a GREAT idea and I hope something comes of it. It looks to have the ability to produce MUCH more power than any conventional IC engine.

Just my .02

 

JoBys correct. The red must remain stationary in order to maintain the striaght line relationship as far as i can tell. I remember doing this as well with my spirograph. Never thought it would become a basis for an engine design, though. There must be another plantetary behind the first planetary set that takes the small circle traced out by the center of the grey inner planet as it traverses the ring gear and converts it into pure rotational motion. Probably have it tied into the spider (or the ring gear) of another gearset jsut behind it.

 

One thing that bothers me is how well a V8 design would stand up to being hammered by eight coffee can sized pistons millions and millions of times. Just think about detonation. The shock could really kill a set of gears. The thing would probably have to be pretty beafy to match the durability of the crank and oil bearing.

 

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Having the plug in the center in the center witht he valves to either side makes it possible to have a CC in the shape closest to the shape of a hemi-sphere, hence the reason for hemi's. Its more efficent then a wedge shaped chamber like the SBC's. I still dont see how that can double power output... The piston still has the same motion as that of one on a standard rotating assy. Jsut no side forces on the skirts. Not only that but there are losses in the planitary trains. They can only be up to around 95% efficient in most cases. Thats losses right there just in the gears. In addition, the gears add lots more moving parts to wear. There are bearings, teeth, gears and so on for each set of pistons. The motion is the identical to that of a standard engine. The centered up and down motion accomplishes the same thing that the connecting rod with bearings at each end does. Turns a circular path into one that is straight. Not only that but Id bet a V8 built with this technolgy would be very expensive. The gears built to close tolerences with helical teeth would really drive up the cost. Good idea for a small engine. Allows for lower wear rates of the piston and cyl. wall and allows for the possibilty of gear reduction built right into the crank case. On a large motor, though, Id bet that it wouldnt be much better then a standard engine with good lube in it.

 

Look at this picture:



You have the 'crank' at the left. It is supported by the large bearing. The moving gear is inserted into the crank and you see a few teeth at a time thru the slot. Then the crank is inserted into the fixed gear you also see in the picture.

That is exaclty what they did ... The piston is the rightmost part on the picture.

This is the rod:

 

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I dont thinkt he ratio could eb varied with the engien itself. The gears are there jsut as a fuction generator to get the 'up and down' motion the piston needs. Works identical to a standard engine. Bore and stroke still apply.

 

I a way, the idea isnt really new, jsut the use of planetary gears to do it. Steam engines have done this but intead used a crank and connecting rod located externally to the cylinder to allow for a longer stroke thats not limited by the bore width / connecting rod length relationships. The real true benifit of this is that it does it in a more compact maner. I dont think we'll see this any time soon but in the future maybe theyll find some way to make an engine more efficient that will require a long stroke with a small bore or something. Then the use of extra parts that add more complexity to the design would be offset by the icnreased thermal efficiency. This is in the same catigory as the variable stroke, constant compression engine. Neat idea, but its time has yet to come.

 

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Of course you could change the number of teeth. You could make it 'course' or 'fine', but the idea is you'd want it optimized. You would want it to be smooth motion (fine), but be able to bite into each other to transfer the power (little bit course). Sorry, not a mechanical eng. I cant think of the word for the number of teeth on a gear if there is one, ha. But changing the number of teeth would do nothing because the relationship is still 1-1.

BTW, Im pretty sure thats a 2-stroke engine on their site. Things will get messy when they start adding a valve-train to that engine. And I dont think we'll be seeing them in large sized motors for a while since 2-strokes arent the most environmentally-friendly type of engines.

And about the power issue. I think these engines would have a lot of potential (assuming they can make them so the gears and drivetrain can hold up) because with a longer stroke, you have more torque. And you can really increase the stroke on an engine on that by making the radius of the circle larger. Like they said you dont have crankshaft journals to worry about. And even with the longer stroke, I think the RPM limit would stay reasonably high because you still have only simple linear motion (and less friction in the cylinder), and seemingly less rotating mass in the bottom end (compared to crankshaft journals). I would think the gears would be able to be lighter than journals on a crankshaft.

If we see them anywhere, it'll be in lawnmowers and weed-eaters, or similar things.

Pretty cool idea I think. Now if I could only come up with something innovative like that...

 

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josh your oil change intervals would be more dependent on the amount of contamination and break down of the oil. not the type of oil used. i doubt if gear oil would be a good choice.

 

The mechanism that transfers the torque to the crank in this weisman engine is the same as a wankel rotary and the rotary is a pretty simple engine -- why would you want to put pistons on a rotary?

 

heh... Didnt even notice that. I definatly have to agree, this is a more complicated way of doing something simple. Looks cool as hell, but I imagine that a full sized 8 cyl. crank forging with teeth cut into it and a surface treatment would cost alot more then what a standard crank would go for, not to mention that youd need ring gears and bearings to go with it.