Patent ID: 8627744

Claim:
An internal combustion engine comprising a crankshaft, the crankshaft comprising: at least five main journals aligned on a crankshaft axis of rotation; and at least eight crankpins, each of the at least eight crankpins being disposed about a respective crankpin axis of rotation and positioned between the at least five main journals; each of the respective crankpin axes of rotation being oriented parallel to, and spaced radially from, the crankshaft axis of rotation; each of the at least eight crankpins being joined to a respective pair of crank arms for force transmission between each of the at least eight crankpins and the respective pair of crank arms; each crank arm being joined to a respective main journal for transmitting torque between the crank arm and the main journal; each respective crankpin axis of rotation of the at least eight crankpins and the crankshaft axis of rotation being disposed approximately in a single plane; said at least eight crankpins comprising a first set of four crankpins and a second set of four crankpins; each respective crankpin axis of rotation of the first set of four crankpins being spaced radially a first semi-stroke distance from the crankshaft axis of rotation, and each respective crankpin axis of rotation of the second set of four crankpins being spaced radially a second semi-stroke distance from the crankshaft axis of rotation; wherein the first semi-stroke distance differs from the second semi-stroke distance.