Continuously variable displacement engine

A variable-displacement engine comprising:

• an engine block;
• a power shaft rotatably supported by the engine block, the power shaft having a longitudinal power shaft axis defining an axial direction and being fixed axially relative to the engine block;
• a cylinder block fixedly mounted to the engine block, the cylinder block defining at least one cylinder, each cylinder having a bore defining a bore axis aligned substantially parallel to the power shaft axis;
• one or more pistons corresponding in number to the number of the cylinders, each respective piston being slidably disposed within the bore of a respective cylinder;
• one or more connecting rods corresponding in number to the number of cylinders, each respective connecting rod having an upper end connected to a respective piston and a lower end connected to a respective connecting rod bearing;
• a wobble plate assembly having a generally annular configuration defining a central opening through which the power shaft passes, the wobble plate assembly including
• a non-rotating first ring portion, the first ring portion including one or more bearing mounting arms formed thereon, corresponding in number to the number of the connecting rods, each bearing mounting arm having the respective connecting rod bearing mounted thereon,
• a rotating second ring portion, the second ring portion being rotatably slidably connected to the first ring portion so as to allow the second ring portion to rotate relative to the first ring portion about a common ring center line while constraining the second ring portion to remain parallel to the first ring portion, and
• a rotation-locking assembly connected between the first ring portion and the engine block to rotationally lock the first ring portion to the engine block while allowing the first ring portion to vary an angle of inclination with respect to the power shaft axis,
• the wobble plate assembly defining a wobble plate inclination plane being a plane passing through the centers of the connecting rod bearings, a wobble plate pivot axis being a line lying in the wobble plate inclination plane and intersecting the longitudinal power shaft axis in a perpendicular orientation and rotating with the power shaft, and a wobble plate angle θ being an angle of intersection between the wobble plate inclination plane and a plane normal to the power shaft axis when viewed in a direction parallel to the pivot axis;
• a piston control mechanism including
• a control yoke attached to the power shaft to rotate with the power shaft and extending radially outward from the power shaft to an anchor line, the location of the anchor line being defined by
• a fixed axial offset distance measured parallel to the power shaft axis from a plane extending perpendicular to the power shaft axis through a theoretical zero point of the wobble plate assembly and
• a fixed radial offset distance measured perpendicular from the power shaft axis;
• a control shaft fixedly mounted to the control yoke at the anchor line;
• a control arm attached to the rotating second ring portion of the wobble plate assembly and extending radially outward to a distal end, the distal end of the control arm forming a control slot defining a slot path;
• wherein the control arm is positioned relative to the control yoke such that the control shaft is captured within the control slot and the control arm is constrained to move such that the anchor point remains along the slot path;
• a lift mechanism connected to the rotating second ring portion of the wobble plate assembly and slidably mounted on the power shaft to be selectively axially movable along the power shaft axis, wherein an axial movement of the lift mechanism results in a corresponding axial movement of the wobble plate assembly and the wobble plate pivot axis;
• whereby selective operation of the lift mechanism to change an axial position of the wobble plate pivot axis selectively changes, via the piston control mechanism, the wobble plate angle θ and an axial distance d between the wobble plate pivot axis and the theoretical zero angle point, which in turn selectively changes a piston displacement of the engine while maintaining a compression ratio of the engine at a predetermined value.