COMPRESSION RATIO ADJUSTABLE DEVICE OF INTERNAL COMBUSTION ENGINE

摘要

PURPOSE:To make it possible to surely prevent free turning to the inner piston of an outer piston by performing projection and recessed engagement of the outer piston and inner piston along the vertical and axial direction. CONSTITUTION:Recessed sections 33 and 33 are formed along the vertical and axial direction on the inner circumference of an outer piston 21. On the other hand, projected sections 35 and 35 to be engaged with the recessed sections 33 and 33 are formed along the vertical and axial direction on the outer circumference of an inner piston 29. This surely prevents the free turning of the outer piston 21 because of the projection-recessed engagement of the recessed sections 33 and engaging projected sections, even if the turning force is acted on the outer piston 21 in a circumferential direction in operating an engine and in switching high and low compression ratio states. Moreover, such contact at faces with each other due to projection-recessed engagement allows facial pressure to be dispersed to the whole of the faces and partial facial pressure to be lessened, which prevents partial abrasion, thereby improving endurance.