Abstract: A free piston linear alternator including a pair of pistons, each piston axially opposed from the other and generating electric current when linearly translating within the cylinder, a combustion chamber disposed between the pistons, a return mechanism configured to return the pistons to respective first positions from respective second positions after combustion; and an exhaust system fluidly coupled to the combustion chamber and including a power turbine transforming exhaust gas feedstream pressure into a mechanical output.

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 free piston linear alternator includes a cylinder having a pair of outer chambers, a pair of opposed pistons and a combustion chamber disposed between the opposed pistons. Each outer chamber is disposed between respective ones of the pistons and a respective outer end of the cylinder. The pistons are axially opposed from each other and independently generate electric current when each of the pistons linearly translate. Each of a pair of return members is disposed within a respective one of the outer chambers, and each of the return members is configured to return respective ones of the pistons to a respective first position from a respective second position after combustion.

Abstract: An internal combustion engine has four cylinders, each having a respective piston positioned therein and connected with a crankshaft for movement in the respective cylinder. Each cylinder has a plurality of ports with a plurality of valves openable and closable to control fluid flow into and out of the cylinder through the ports. Combustion occurs in a first two of the four cylinders (power cylinders) that are each interconnected between a second two of the four cylinders (inductor cylinders) via passages connecting ports of the respective cylinders. Opening and closing of the valves is timed to accomplish internal exhaust gas recirculation, i.e., such that fluid directed from the power cylinders to the inductor cylinders via the passages after combustion is redirected via the passages from the inductor cylinders to the power cylinders. A method of internal exhaust gas recirculation for an engine as described above is also provided.

Abstract: A free piston linear alternator includes a cylinder having a pair of bounce chambers, a pair of scavenging chambers, a pair of opposed pistons and a combustion chamber disposed between the opposed pistons. The pistons are axially opposed from each other and generate electric current when each of the pistons linearly translate. Each of the bounce chambers is disposed between respective ones of the pistons and a respective outer end of the cylinder and includes substantially constrained air configured to return respective ones of the pistons to a respective first position from a respective second position after combustion.

Abstract: An internal combustion engine has a first work extraction station for extracting work from combustion and expansion of working gases. An emission treatment station treats the working gases after leaving the first extraction work station for reducing emissions. A second work extraction station receives the working gases from the emission treatment station for a second extraction of work from the working gases.

Abstract: A method for managing thermal energy in an internal combustion engine including an exhaust gas recirculation system and an engine cooling system includes recirculating a portion of an exhaust gas through the exhaust gas recirculation system that is in thermal communication with a first side of a thermoelectric device, flowing an engine coolant into thermal communication with a second side of a thermoelectric device, and controlling electric current between an electrical energy storage device and the thermoelectric device to transfer thermal energy between the recirculated exhaust gas and the engine coolant.

Abstract: An internal combustion engine includes a compressor cylinder having a respective inlet, a first outlet and a respective piston slideably movable within the compressor cylinder and operatively connected to a rotating crankshaft. The compressor cylinder provides a first stage of compression to a charge when the charge is transferred from the compressor cylinder during every revolution of the crankshaft. A first power cylinder includes a respective inlet in fluid communication with the first outlet of the compressor cylinder, a respective outlet and a respective piston slideably movable within the first power cylinder and operatively connected to the rotating crankshaft. The first power cylinder provides a second stage of compression and firing of the charge within the first power cylinder every two revolutions of the crankshaft.

Abstract: A compression-ignition internal combustion engine includes a plurality of combustion chambers operating in a four-stroke combustion cycle and is configured to operate at a geometric compression ratio greater than 10:1. A method for operating a the engine includes forming a fuel/air charge by injecting fuel into each combustion chamber during a compression stroke, wherein the injection is completed prior to any combustion within the combustion chamber. The method further includes operating the engine to manage temperature of the fuel/air charge in the combustion chamber below an auto-ignition point of the fuel/air charge, and providing a spark discharge in the combustion chamber subsequent to injecting the fuel and in advance of the fuel/air charge achieving an auto-ignition temperature.

Abstract: Engines and processes for their operation include a compressor cylinder, at least one power cylinder, and an expander cylinder. The outlet of the compressor cylinder is fed to the inlet of a power cylinder, and the outlet of the power cylinder is fed to the expander cylinder. The compressor cylinder and the expander cylinder are operated in two-stroke fashion, and the power cylinder is operated in four-stroke fashion, all of which cylinders share a common crankshaft. Heat may be recuperated from the exhaust gas and directed to the inlet gas of the power cylinder, increasing overall efficiency.

Abstract: An apparatus, system, and method are disclosed for efficiently operating an engine utilizing exhaust gas recirculation (EGR). The apparatus includes an exhaust manifold receiving exhaust gas from a first cylinder set, an EGR manifold receiving exhaust gas from a second cylinder set, and a passage comprising a variable restriction. The passage fluidly couples the exhaust manifold to the EGR manifold. The apparatus further includes a controller with modules for interpreting engine operating conditions and controlling actuators in response to the engine operating conditions.

Abstract: An internal combustion engine has a first work extraction station for extracting work from combustion and expansion of working gases. An emission treatment station treats the working gases after leaving the first extraction work station for reducing emissions. A second work extraction station receives the working gases from the emission treatment station for a second extraction of work from the working gases.

Abstract: A free piston linear alternator including a pair of pistons, each piston axially opposed from the other and generating electric current when linearly translating within the cylinder, a combustion chamber disposed between the pistons, a return mechanism configured to return the pistons to respective first positions from respective second positions after combustion; and an exhaust system fluidly coupled to the combustion chamber and including a power turbine transforming exhaust gas feedstream pressure into a mechanical output.

Abstract: A free piston linear alternator includes a cylinder having a pair of bounce chambers, a pair of scavenging chambers, a pair of opposed pistons and a combustion chamber disposed between the opposed pistons. The pistons are axially opposed from each other and generate electric current when each of the pistons linearly translate. Each of the bounce chambers is disposed between respective ones of the pistons and a respective outer end of the cylinder and includes substantially constrained air configured to return respective ones of the pistons to a respective first position from a respective second position after combustion.

Abstract: A free piston linear alternator includes a cylinder having a pair of outer chambers, a pair of opposed pistons and a combustion chamber disposed between the opposed pistons. Each outer chamber is disposed between respective ones of the pistons and a respective outer end of the cylinder. The pistons are axially opposed from each other and independently generate electric current when each of the pistons linearly translate. Each of a pair of return members is disposed within a respective one of the outer chambers, and each of the return members is configured to return respective ones of the pistons to a respective first position from a respective second position after combustion.

Abstract: A method for controlling combustion in a direct-injection diesel engine includes monitoring a crankshaft rotational position of a cylinder of the engine, monitoring an engine load, determining an intake stroke within the cylinder based upon the crankshaft rotational position, and when the engine load is less than a threshold engine load, opening an exhaust valve for the cylinder during a portion of the intake stroke.

Abstract: A method for managing thermal energy in an internal combustion engine including an exhaust gas recirculation system and an engine cooling system includes recirculating a portion of an exhaust gas through the exhaust gas recirculation system that is in thermal communication with a first side of a thermoelectric device, flowing an engine coolant into thermal communication with a second side of a thermoelectric device, and controlling electric current between an electrical energy storage device and the thermoelectric device to transfer thermal energy between the recirculated exhaust gas and the engine coolant.

Abstract: A compression-ignition internal combustion engine includes a plurality of combustion chambers operating in a four-stroke combustion cycle and is configured to operate at a geometric compression ratio greater than 10:1. A method for operating a the engine includes forming a fuel/air charge by injecting fuel into each combustion chamber during a compression stroke, wherein the injection is completed prior to any combustion within the combustion chamber. The method further includes operating the engine to manage temperature of the fuel/air charge in the combustion chamber below an auto-ignition point of the fuel/air charge, and providing a spark discharge in the combustion chamber subsequent to injecting the fuel and in advance of the fuel/air charge achieving an auto-ignition temperature.

Abstract: An apparatus has an internal combustion engine configured to operate at a lean air/fuel ratio and includes an exhaust aftertreatment system including an oxygen separator fluidly connected upstream of a three-way catalytic converter.

Abstract: An internal combustion engine has four cylinders, each having a respective piston positioned therein and connected with a crankshaft for movement in the respective cylinder. Each cylinder has a plurality of ports with a plurality of valves openable and closable to control fluid flow into and out of the cylinder through the ports. Combustion occurs in a first two of the four cylinders (power cylinders) that are each interconnected between a second two of the four cylinders (inductor cylinders) via passages connecting ports of the respective cylinders. Opening and closing of the valves is timed to accomplish internal exhaust gas recirculation, i.e., such that fluid directed from the power cylinders to the inductor cylinders via the passages after combustion is redirected via the passages from the inductor cylinders to the power cylinders. A method of internal exhaust gas recirculation for an engine as described above is also provided.