Piston compound internal combustion engine with expander deactivation

摘要

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.

主权项

1. A piston compound internal combustion engine with expander de-stroking, said engine comprising:
two power pistons coupled to a rotating crankshaft, said power pistons providing engine power as a result of a primary expansion of combustion gases from ignition of a fuel-air mixture; a secondary expander piston, said expander piston providing additional engine power as a result of a secondary expansion of the combustion gases after the primary expansion by the power pistons; a de-stroking mechanism for reducing or eliminating a stroke of the expander piston under certain engine conditions; and a controller configured to measure engine conditions, establish a desired stroke of the expander piston based on the engine conditions, and communicate the desired stroke to the de-stroking mechanism.