I know how to do it, but it will cost you 5 million dollars for the plans!! ;D ;D---Its not a big deal to make a double acting steam engine, because a steam engine doesn't require "internal combustion" in the cylinder to expand the steam. The steam is heated externally, and can actually be thought of as an "external combustion" engine. Current 4 cycle i.c. engines depend on the downstroke of the piston to draw a charge of air/fuel mixture into the cylinder, then an upstroke of the piston to compress the mixture before igniting it to create a power stroke. Two cycle engines do much the same thing, except that the downstroke of the piston pressurizes the air/fuel mixture in the crankcase, and thru a "slide valve" effect created by the piston skirt, this "pressurized charge" rushes into the cylinder to be ignited on every piston stroke. To do what you want to do, I think you can get around the fuel issue by using fuel injection into the cylinder at the correct time prior to igniting it. To create a charge of compressed air which would be injected into the cylinder at the critical time, you would need two "slave cylinders" with slide valve mechanisms. These "slave cylinders" would never have ignition occuring in them---they would only compress air, which would be injected into the "ignition cylinders" at the proper time in the cycle. For a more thorough explanation, and a complete set of plans, just send cash, cheque, or money order in the ammount of $5,000,000 and I will send them right away.---Brian
