Abstract: A single-shaft dual expansion internal combustion engine is described, and includes an engine block including first and second power cylinders and an expander cylinder fluidly coupled through a cylinder head, and first and second power pistons that connect to respective first and second crankpins of the crankshaft. A multi-link connecting rod assembly includes a rigid main arm extending orthogonally to a longitudinal axis of the crankshaft and supporting a first pivot pin, a second pivot pin and a third pivot pin. The first pivot pin connects via a connecting rod to an expander piston reciprocating in the third cylinder. A third crankpin of the crankshaft serves as the second pivot pin and has a throw that is located 180 degrees of rotation of the crankshaft from a throw of the first crankpin. The third pivot pin connects to a swing arm connected to the engine block.

Abstract: A single-shaft dual expansion internal combustion engine includes first and second power cylinders and an expander cylinder. The cylinder head fluidly couples the first and second power cylinders and the expander cylinder. First and second power pistons reciprocate in the first and second power cylinders and connect to a first crankpin of the crankshaft. A multi-link connecting rod assembly includes a rigid main arm supporting a first pivot pin, a second pivot pin and a third pivot pin. The first pivot pin connects to an expander piston reciprocating in the third cylinder. The third pivot pin couples to a first end of a swing arm, and a second end of the swing arm rotatably couples to a fourth pivot pin that couples to a distal end of a rotating arm that attaches to a rotating shaft coupled to rotation of the crankshaft.

Abstract: A single-shaft dual expansion internal combustion engine is described, and includes an engine block including first and second power cylinders and an expander cylinder fluidly coupled through a cylinder head, and first and second power pistons that connect to respective first and second crankpins of the crankshaft. A multi-link connecting rod assembly includes a rigid main arm extending orthogonally to a longitudinal axis of the crankshaft and supporting a first pivot pin, a second pivot pin and a third pivot pin. The first pivot pin connects via a connecting rod to an expander piston reciprocating in the third cylinder. A third crankpin of the crankshaft serves as the second pivot pin and has a throw that is located 180 degrees of rotation of the crankshaft from a throw of the first crankpin. The third pivot pin connects to a swing arm connected to the engine block.

Abstract: A single-shaft dual expansion internal combustion engine includes first and second power cylinders and an expander cylinder. The cylinder head fluidly couples the first and second power cylinders and the expander cylinder. First and second power pistons reciprocate in the first and second power cylinders and connect to a first crankpin of the crankshaft. A multi-link connecting rod assembly includes a rigid main arm supporting a first pivot pin, a second pivot pin and a third pivot pin. The first pivot pin connects to an expander piston reciprocating in the third cylinder. The third pivot pin couples to a first end of a swing arm, and a second end of the swing arm rotatably couples to a fourth pivot pin that couples to a distal end of a rotating arm that attaches to a rotating shaft coupled to rotation of the crankshaft.

Abstract: A piston compound internal combustion engine is disclosed with an expander piston deactivation feature. A piston internal combustion engine is compounded with a secondary expander piston, where the expander piston extracts energy from the exhaust gases being expelled from the primary power pistons. The secondary expander piston can be deactivated and immobilized, or its stroke can be reduced, under low load conditions in order to reduce parasitic losses and over-expansion. Two mechanizations are disclosed for the secondary expander piston's coupling with the power pistons and crankshaft. Control strategies for activation and deactivation of the secondary expander piston are also disclosed.

Abstract: A piston compound internal combustion engine is disclosed with an expander piston deactivation feature. A piston internal combustion engine is compounded with a secondary expander piston, where the expander piston extracts energy from the exhaust gases being expelled from the primary power pistons. The secondary expander piston can be deactivated and immobilized, or its stroke can be reduced, under low load conditions in order to reduce parasitic losses and over-expansion. Two mechanizations are disclosed for the secondary expander piston's coupling with the power pistons and crankshaft. Control strategies for activation and deactivation of the secondary expander piston are also disclosed.