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Atkinson Differential Engine.
- Thread starter Larry_C9
- Start date
It is actually a bit like that but quite different in that it is a four stroke engine and gets all four strokes during one revolution of the crankshaft. This engine was designed to prove a theory and as far as I understand when it does run it does not make enough power to drive anything. Barely enough to keep itself going. If I fasten a plate to the top of one piston to boost the compression it should bring it up near what the plans show. Either I got a dimension wrong or there is an error in the plans book because the way mine now is the pistons don't come together close enough on the compression stroke. If you google Atkinson differential engine by Vincent R. Gingery there is lots of information about this engine. Even a video showing one of his engines running.
Well, still trying to get to a handle on this engine. Most of the web stuff that comes up is not really about this engine, and so far what does seems not to show the porting, a pain.
Any how, could the porting be slightly wrong, along with a leaking exhaust or intake poppet valve, all in hand with a lack of compression from a short piston?
Worked on a 4-53 jimmy once that would not run rite, would start and idle poorly, nearly die when opening throttle and not come to high idle, all while smoking very bad. If the exhaust was blocked half off or a bit more, would run much better. A bunch of head banging. Turned out a difference in early and later blocks, we had got pistons and sleeves for later blocks and we had early block.
What you don't know.
I need to check out more on Vincent Gingery's engine.
Any how, could the porting be slightly wrong, along with a leaking exhaust or intake poppet valve, all in hand with a lack of compression from a short piston?
Worked on a 4-53 jimmy once that would not run rite, would start and idle poorly, nearly die when opening throttle and not come to high idle, all while smoking very bad. If the exhaust was blocked half off or a bit more, would run much better. A bunch of head banging. Turned out a difference in early and later blocks, we had got pistons and sleeves for later blocks and we had early block.
What you don't know.
I need to check out more on Vincent Gingery's engine.
Here is the link to the video that explains how the Atkinson engine works and shows it running.
Bandit I know exactly what you are talking about. I have done some work on Detroit engines but most of my time was on Caterpillar. You have to be so careful with them, specially the engines. You need the serial number and the arrangement number because the same engine configuration is used in so many different applications.
Same with Cummins.....
So it is a 4 stroke. I gotta learn to read better. I feel like I'm on a teeter totter surrounded by hungry gators!
Thanks for the link. I am soooo curious!
Another update. I made the little plate and attached it to the head of the right piston. Looked a lot better on the compression stroke but when the pistons come together on the right side for the exhaust stroke they come closer together and with the plate on the right piston they contact and won't allow the engine to rotate any farther. So I dug out the wooden mock up they suggest you build first to get the idea how it is supposed to work. The pivot points for the arms are at different heights in relation to the crankshaft and the cylinder barrel. The right pivot is 1/8" lower which makes it closer to the cylinder barrel and farther away from the crankshaft pivot point than the left side. This makes the pistons travel at different speeds at different parts of the engine rotation. This is very difficult to explain in just words. Even looking at the wooden mock up I am not sure what I can do to get the pistons closer together on the compression side without them contacting on the exhaust side. I can easily put the engine back the way it was built by removing the plate I put on top of the right piston and loctiting a couple of set screws in the tapped holes I made in the piston. I may try to change the timing and try to run it backwards. I guess I should study the mock up and see if I can figure out if that might work.
Is there an easy way to measure compression pressure on it? Pull spark plug, hook up compression tester?
I just watched a you tube by "Tuble Cain"? last week on the travel of a shaper ram, showed a mock up of ram and drive gear linkage and how the ram will travel faster in one direction then the other over the same distance.
I am still wondering if poppet valves are sealing or maybe a bad piston ring. A leak down test with low pressures, maybe 5 to 10 psi max? Slowly turn engine and see what leaks?
Yes, I do watch a few you tube "vids". Still figuring this engine out ,(trying to), may have to get the book and make mock up to "get it".
Is one piston on the intake port and the other on the exhaust port?
I just watched a you tube by "Tuble Cain"? last week on the travel of a shaper ram, showed a mock up of ram and drive gear linkage and how the ram will travel faster in one direction then the other over the same distance.
I am still wondering if poppet valves are sealing or maybe a bad piston ring. A leak down test with low pressures, maybe 5 to 10 psi max? Slowly turn engine and see what leaks?
Yes, I do watch a few you tube "vids". Still figuring this engine out ,(trying to), may have to get the book and make mock up to "get it".
Is one piston on the intake port and the other on the exhaust port?
Yes. As I understand it!
RE shaper - I had to draw that out to understand it. Made me want one!
I have kind of run out of ideas for the time being. I believe it is because of the positioning of the pivot shafts which give a different linkage geometry to each side at any given position in the crank rotation that the distance between the piston tops is greater on the compression side than on the exhaust side. I will have to read the complete article on the HMEM forum to see if the changes he made ended up in a running engine. I know he was taking about decreasing the verticle distance between the pivot shafts when he built his version. It certainly is an interesting design and quit a sight when it is rolling over. Mine has spent plenty of time rolling over with an electric motor driving it. It does fire weakly but does not develop enough power to start and run on it's own when you give the flywheel a flip. The coolant and cylinder get quit warm after a while when running from the motor,so that tells me there is fire in there.