[RICHARD ZASTROW]

How about externally adjustable compression ratio? www.psipowerinc.com/heads.htm

I realize these are two-stroke snowmobile heads. I just intended to bring forth the idea.

FYI, a 340cc two-stroke, naturally aspirated snowmobile engine in race trim on gasoline fuel produces~115 hp (86kw). Thats 338hhp(253kw)/litre

Dick Z

[GreasyC]

FYI, a 340cc two-stroke, naturally aspirated snowmobile engine in race trim on gasoline fuel produces~115 hp (86kw). Thats 338hhp(253kw)/litre

Dick Z

Before MotoGP switched to four strokes the 500cc naturally aspirated, two stroke, V4 engines were similarly producing almost 200 hp, or 400hp/L.

[christinaB]

Some people may have realized that some newer cars are said to be using the “Atkinson cycle,” especially on hybrids. The key characteristic of the Atkinson cycle is finishing all four “strokes” of an engine cycle with one turn of the crankshaft, which is more cost-effective. The Information on the Atkinson cycle was made clear. The goal of the modern Atkinson cycle is to allow the pressure in the combustion chamber at the end of the power stroke to be equal to atmospheric pressure; when this occurs, all the available energy has been obtained from the combustion process. For any given portion of air, the greater expansion ratio allows more energy to be converted from heat to useful mechanical energy meaning the engine is more efficient.