Abstract: A crankshaft is rotatably supported by an engine block and rotatable about a crank axis. An eccentric shaft is rotatably supported within the engine and rotatable about an eccentric shaft axis, wherein the eccentric shaft axis is parallel to and distal from the crank axis. A speed change mechanism interlinks movement of the eccentric shaft and the crankshaft. The speed change mechanism selectively varies a ratio of a rotational speed of the eccentric shaft relative to a rotational speed of the crankshaft from 1:1 to one of: ?8:1, ?6:1, ?4:1, ?2:1, ?1:1, ?0.5:1, 0:1, 0.5:1, 1:1, 2:1, 4:1, 6:1, and 8:1, thereby causing the eccentric shaft to rotate at a speed different from the crankshaft and varying a rotational position of the eccentric shaft relative to the crankshaft.

Abstract: An engine assembly including a crankshaft, a bell crank pivotally mounted on the crankshaft, the bell crank having a first end and a second end opposite of the first end, a connecting rod connected to the first end of the bell crank, a control shaft, a control link mounted on the control shaft and connected to the second end of the bell crank, a driven gear fixed to the crankshaft, a drive gear fixed to the control shaft, an actuator, and a split-torque gear box splitting the torque from the driven gear between the drive gear via a first torque path and the actuator via a second torque path.

Abstract: A crankshaft is rotatably supported by an engine block and rotatable about a crank axis. An eccentric shaft is rotatably supported within the engine and rotatable about an eccentric shaft axis, wherein the eccentric shaft axis is parallel to and distal from the crank axis. A speed change mechanism interlinks movement of the eccentric shaft and the crankshaft. The speed change mechanism selectively varies a ratio of a rotational speed of the eccentric shaft relative to a rotational speed of the crankshaft from 1:1 to one of: ?8:1, ?6:1, 4:1 ?2:1, ?1:1, ?0.5:1, 0:1, 0.5:1, 1:1, 2:1, 4:1, 6:1, and 8:1, thereby causing the eccentric shaft to rotate at a speed different from the crankshaft and varying a rotational position of the eccentric shaft relative to the crankshaft.