Two-cycle dry-sump fuel-injected engine

An internal combustion engine, comprising:

• a cylinder block with piston bores that step up substantially in diameter between a top portion of each cylinder and a corresponding bottom portion;
• a piston with steps matching said piston bores and its outside diameter having a larger diameter lower half with a piston skirt and a seal ring, and an upper half with at least one compression ring disposed near the top;
• a crankcase and a crankshaft with a connecting rod attached to the piston, and including a port to intake fresh air for combustion;
• a jacket chamber surrounding the piston that changes in volume as the piston travels up and down as a consequence of there being matching stepped diameters on the piston and corresponding cylinder bore;
• a combustion chamber disposed above the piston;
• a fuel injector connected to the combustion chamber and providing for the injection of fuel at particular times to create an air-fuel mixture;
• a spark plug disposed in the combustion chamber and providing for the igniting of said air-fuel mixture at particular times;
• an exhaust valve for venting out exhaust gases from the combustion chamber at particular times;
• and
• an air passageway connecting from the crankcase to a port disposed in a lower side of each said top portion of each cylinder, and that provides for a charge of fresh air into the combustion chamber that was first drawn into the crankcase by an upstroke of said lower half of the piston;
• wherein, a two-cycle operation is supported.