two strokes ain't dead....yet
thought you might like to see some work in progress, it's a concept design for a 2-stroke. It's a principle that's usually applied to marine diesel uniflow 2-strokes (the most efficient internal combustion engines on the planet), but I though that given the trend towards ever-smaller capacities and supercharging, the time might be right for something like this. Scavenging and supercharging is done by a screw compressor, inlet is via cam-operated poppet valves and direct combustion chamber fuel injection. This is spark ignition but could also be a diesel, although they have fallen out of favour recently because of NOx. Exhaust is via exhaust ports on both sides of the cylinder which gives an enormous port area, so the port roof can be lower, giving a longer power stroke. This has a bore:stroke ratio of 1:1 which these days is very low, it won't rev above 7000rpm but doesn't have to because of supercharging - bmep is therefore high at 262psi, giving 250 bhp from 800cc. Very long conrods give little sidethrust on the pistons, which enables lower lubricant levels to be used, and thus lower oil loss through the exhaust port as the rings pass over it. It'll be very loud, think of a kawasaki kettle on steroids. A lot of steroids.