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Make mine a double.
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Chaingine
Chain drive compression combustion engine. Technology is always chaingine. | |
This is a compression combustion engine, that utilizes a heavy duty chain that doubles as a combustion chamber. It is comprised of a chain similar to that of a bicycle or a motorcycle. There is an oil reservoir at one end that contains vegetable biodiesel which acts as both a fuel and a lubricant of
the chain. At the other end is a hub sprocket that turns a wheel and is involved in the compression cycle.
As the chain rotates, perhaps initiated by pedalling, oil steadily drips into the openings of the chain into which the sprocket will enter. Some oil lubricates the chain, while some atomized oil accumulates in the chain, as it is capped without an opening at the top, as most chains have.
When the chain passes under the sprocket which is attached to the hub, the teeth engage the chain, causing a compression of the air oil mixture in this heavy duty chain. This causes combustion and expansion of the gas volume, which causes the sprocket to rotate anticlockwise driving the wheel.
As the chain returns over the top of the sprocket it cools before it repeats the cycle. A similar engine technology can utilize spur gears interlocking causing the compression. In theory, the mechanical efficiency of this design would be higher than having a piston driving the chain, driving the sprocket.
Imagine the outside of the chain capped, and the combustion occuring as the chain passes under the sprocket.
http://www.osha.gov...imations/chain.html
Perhaps on the return cycle, the chain can be cooled by a water, oil mixture. [rcarty, Dec 18 2007]
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Don't we need a spark at the compression point? |
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So we are just making a rotary engine out of a bicycle. Sounds half-baked to me so far. |
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please do us a favor. make this out of magnesium and take lots of pictures. it will be a one time show. |
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I don't see getting a sprocket tooth to go up into, seal and compress a chamber in a chain. It would have to hold that pressure while the sprocket rotated, which would be even harder to manage. And the chain would sometimes be driving the wheel, sometimes be driven. |
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Part of the beauty of a chain is the limited friction area of the teeth, and the rollers on the chain. This idea loses that. Creative, though. [ ] |
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At the risk of unduly returing the conversation to the subject at hand, I still don't know where the spark is for the ignition. |
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[pigmeatmind] wanted to know how the compression is achieved, but I can half-bake that in my mind with whatever it is that seals the chambers of a rotary engine. But kita certainly won't be compressing any earthly chain-lubricating fuel enough to get spontaneous combustion, will kita? |
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I don't know what you people are talking about. |
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// I still don't know where the spark is for the ignition. // |
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There *is* no spark ..... |
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Didn't you note his reference to biodiesel ? Look at a 2-stroke model aircraft diesel engine - it can be done. But these tiny diesels use fuel doped with nitro compounds - expensive. |
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I think the oil will be a little light for lubrication, or a little heavy for diesel combustion, especially with the very small cylinders and the sealing needed for diesel ignition (30-40atm). |
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Admittedly vegetable biodiesel may not be the most practical choice, especially in the conceptual stage. |
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Where is the seal that allows compression of the air/fuel mixture? Wouldn't this be the same seal that held in the compression of combustion? How does the energy of combustion do work? These basic questions have not be resolved. |
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Your description seems to describe ignition producing force that would tend to make the chain try to jump off the sproket but would not make the sproket turn faster. No force applied in the direction of the centerline of the sproket or pushing out from that centerline can do any work. |
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Also I would note that your link makes reference to a "water oil mixture" for coolant. Describe better how you would achieve such an interesting mixture. Also seek out information on diesel engines. Injection of some sort is a must as combustion of a puddle or film of diesel just isn't going to happen even under the best conditions. |
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More of an emulsion than a mixture, but a mixture nonetheless. The 'cylinder' of the chain would be airtight and have links connected to it. |
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//producing force that would tend to make the chain try to jump off the sproket //
Right, thereby pulling on the next link which drives the sprocket. |
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The combustion would occur not at the centreline but after having passed beyond that. |
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I just dont see that. The force applied to one link would simply be wasted trying to seperate that link from its neighbor. You have to think about how the system captures work (where does the energy go). Also you still need a fuel system of some sort. |
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How does a piston trying to jump out of a cylinder drive a crankshaft? It's rotating. The combustion drives to sprocket upwards and the chain away from the the sprocket, pulling the next link. |
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The piston TURNS a crank. (by applying rotational force) |
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Lets say now that the sprocket teeth are indestructable spark plugs, for simplicity sake. And each individual chain cylinder is full of high octane (to delay ignition) gasoline vapour. The combustion takes place not as the chain passes under the centrepoint, but slightly thereafter when the sparkplug fires and the gas ignites. This drives the chain away from the sprocket and the sprocket away from the chain, upwards. |
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I can see that now if i imagine a curved guide in which the chain is guided against the sproket but you must recognise that to do work combustion has to use a certain amount of space. Like the optimum length for the barrel of a gun a reciprocating engine must have a change in volume. This requires some sort of seal. How can you seal the surfaces inside the link to the sproket and still allow the link to push away from the sproket? |
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Imagine that the sproket is a ring of pistons and the chain is a series of cylinders. The "power" portion of the stroke is only the last 35 degrees of rotation and the force is applied to the centerline of the sproket. Most of the energy is wasted at this angle and the seals have work on a rolling curve. Still i can now see how it might sorta work. |
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The seals were not meant to be airtight. During ignition, the exhaust gases would expand to do some work, escaping from the cylinder. Because of the rapid succession of combustion less work can be expected from each ignition. |
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My thoughts turned to modifying the sprocket too. However, this was merely meant to be a concept engine so I tried to get away with a superficial description. |
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Even a halfbaked idea deserves a good description. The longer you can make the teeth the better. The waste energy here will be 90%+. |
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It's apparent that the sprocket needs to be modified to allow exhaust gases to escape. In the meantime, I will propose that a gas jet valve angled in the opposite direction of the movement of the chain, will release the blast of ignited gas from each link. |
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Lets imagine for a second. |
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Put the sproket in channel that makes a U shape. Make the sproket out of a ring of pistons. Make the chain out of a series of small close ended cylinders. Ignore the problems that this poses. Then provide that the chambers fill with a combustable mixure as they enter the guide. As they rotate through the guide the pistons enter the chambers compresing the mixture. As they leave ignition is provided forcing the piston out of the cylinder and turning the sproket. It poses all kinds of problems but it does seem like it would work.
Keep the idea simple. Avoid valves and such and focus on how you can make the teeth behave like pistons. (I think pistons mounted on pins would work but then you have a fixed crank engine with lots of extra cylinders.) |
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Well then I give it my bun. :] |
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