Patent ID: 7159544
Filing Date: 2007-01-09
Classification: F02B,F02D

Abstract:
1. An engine comprising: at least one cylinder bore having a cylinder wall; a piston positioned within the cylinder bore and adapted for reciprocal movement therein; at least one piston sleeve positioned within the cylinder bore, radially between the piston and the cylinder wall, extending around the piston, and adapted for reciprocal movement therein, the piston and the piston sleeve being able to move independently of one another; a stop for selectively securing the piston sleeve stationary within the cylinder adjacent a top portion of the cylinder, wherein when the stop is de-activated, the piston and the piston sleeve move together within the cylinder, and when the stop is activated, the piston sleeve is secured adjacent the top portion of the cylinder and the piston moves reciprocally within the piston sleeve.