Half cycle eccentric crank-shafted engine

An internal combustion engine comprising:

• an engine block forming at least one cylinder with a central axis;
• a piston adapted to reciprocate linearly within said at least one cylinder along said central axis between a top dead center position and a bottom dead center position;
• a crank shaft assembly mounted within said engine block, said crank shaft assembly including a drive shaft with a drive shaft axis and a hollow piston rod leg base;
• a piston rod extension associated with said piston rod leg base, the piston rod extension having a first end adapted to travel in a reciprocating manner from a retracted position to an extended position, the first end being further within said hollow piston rod leg base in said retracted position than in said extended position, and a second end exterior to said hollow piston rod leg base, said second end including a guide;
• a piston rod having a first end pivotally connected to said piston and a second end pivotally connected to said second end of said piston rod extension;
• a guide channel associated with said engine block, said guide channel eccentrically circumscribing said drive shaft axis;
• whereby during rotation of said drive shaft, said piston reciprocates between its top dead center and bottom dead center positions, and said guide travels along said guide channel to influence said second end of said piston rod extension between its retracted position as the piston moves from a position substantially at top dead center to its extended position when said piston is approximately half way between its top dead center and bottom dead center positions.