I have not seen a lot of discussion of what I am calling the Atkinson Valve Engine used, for example, in the Toyota Prius and other cars. This engine looks like a conventional four-stroke OHV design, except that it has a very high basic compression ratio. The Atkinson aspect of it lies in the fact that a fraction of the intake charge is recirculated back into the intake manifold by delaying the close of the intake valve until partway through the compression stroke. That effectively allows a modest compression ratio appropriate for a gasoline engine and a large expansion ratio to extract more energy during the power stroke. That’s about as simple as I can find words to explain the basic idea.
I don’t believe I’m the only one to try this idea. I expect I could learn a lot from the judgement and advice of HMEM forum participants who have an interest in this area.
It all began with a Gingery Atkinson Differential engine I made starting in 2002. It was a bit of a nightmare to get it to run, but it eventually did so in many shows -- until I scored the cylinder by skimping on oil mixture in the fuel during 2011. Restoration of this engine turned into the beginning of another nightmare, so in in November of 2015 I got out a clean sheet of paper and began the design of an “Atkinson Valve Engine.”
It took me over six years to design and make the castings and machined parts. Then the fun began. A year later, after fixing more amateurish errors than I ever thought possible, the engine actually started and ran. Some of the ignition experiments I’ve done for this project – and have yet to complete – are already posted under the thread “Tests of CDI Ignition Modules” on HMEM. There’s a lot of work to do to get this beast show ready. It needs work on water leaks, oil consumption, valve and ignition timing, wiring, display stand, and more.
I’d value comments, suggestions, critique, and ideas for improvement.
I don’t believe I’m the only one to try this idea. I expect I could learn a lot from the judgement and advice of HMEM forum participants who have an interest in this area.
It all began with a Gingery Atkinson Differential engine I made starting in 2002. It was a bit of a nightmare to get it to run, but it eventually did so in many shows -- until I scored the cylinder by skimping on oil mixture in the fuel during 2011. Restoration of this engine turned into the beginning of another nightmare, so in in November of 2015 I got out a clean sheet of paper and began the design of an “Atkinson Valve Engine.”
It took me over six years to design and make the castings and machined parts. Then the fun began. A year later, after fixing more amateurish errors than I ever thought possible, the engine actually started and ran. Some of the ignition experiments I’ve done for this project – and have yet to complete – are already posted under the thread “Tests of CDI Ignition Modules” on HMEM. There’s a lot of work to do to get this beast show ready. It needs work on water leaks, oil consumption, valve and ignition timing, wiring, display stand, and more.
I’d value comments, suggestions, critique, and ideas for improvement.
