I wondered the same thing. The two outermost cylinders appear to be a standard 4-cycle, but if I'm seeing the video correctly, each of them exhausts not to the air but into the central cylinder, pushing it down; I'm not sure but I think maybe the idea is that the mixture is still burning at this point ... ??
This is a technology currently being explored for automotive engines. Using exhaust gas pressure to drive the crankshaft directly.
I have seen a configuration in which a 4 cylinder engine can run in the conventional way, but also has the ability, via variable valve timing and additional valves between cylinders, to become a 2 cylinder engine with the other 2 used to scavenge residual exhasut gas pressure.
Hi, I think the technical analysis is that there are a total of 10 strokes per 1 complete cycle (2 crank revolutions) on a real 5-stroke engine. But if you count this engine, I think there are 4-strokes in a primary cylinder, with an extra 2-strokes of the secondary cylinder appropriate to the primary cylinder, associated with each combustion charge. Therefore I would call this a 6 stroke engine. I have seen this engine schematic on u-TUBE, but can't recall how I searched and found it. I think Peter is correct in that some manufacturers have investigated this configuration historically.
But one of the things I learned working for a car maker, was that if it would make money we would do it, otherwise we wouldn't invest in developing it. This engine may appear thermodynamicallying efficient. But as we live in a world of regulation, where we practice making muck then cleaning it up afterwards, the exhaust on today's vehicles is required to be hot, so to set the catalysts working that clean-up exhaust emissions. In this engine, I understand the second expansion will cool the exhaust so the CO will cease to burn, so it will need an external heat source to re-heat the gas to above 350 degrees C so the CO will burn to CO2. This in turn needs the catalyst to be heated over 650 C to get it to ignite the CO. The same argument applies to Hydro-carbons. If the primary cylinders run over 90 then the Nitrous oxides will be formed in nasty quantities, thus requiring NOx after-treatment. But I guess as a model none of that will be needed so this is purely academic.
I interesting thread!
Are you trust the radius of that screws? Although it is a practical solution I know that the heads of the screws are made by pressing, not on turning machine. There is a possibility that each of them is of different diameters or eccantric. Still it will probably works.
Looks nice and I've no doubt it will run.
It may be interesting to measure the engines output with and without the '5th stroke' cyclinder active. Maybe first run with the middle piston and rod removed and exhausts from 1 and 3 open to atmosphere?
I have never seen a valve ground like that - but well done if it works for you. I have only used a Delapena Valve grinder, where the stone traverses along the tapered angle required. Typically, 45 degrees for half the face and 46degrees for the other half, so the line between the 2 tapers forms the specific sealing line which is lapped against the seat until the appropriate seat width is made. (Too narrow and it may indent the seat before it laps properly, too wide - e.g all one angle - and the lapped ring may be on the inner or outer edge of valve or seat, depending on how the valve taper matches the seat taper). Perhaps your model is small enough to be insensitive to seat accuracy? - But I guess it may be more sensitive? You'll see when it runs.