Abstract: Disclosed is an engine valve port including a valve opening, a first portion, and a separate second portion. The first portion and the second portion are separately connected to the valve opening, and the first portion and the second portion merge together at a location spaced from the valve opening. The valve port has a bifurcated, porpoise-like shape. The first portion and the second portion are generally arcuate in shape, and the first portion and the second portion have a generally semicircular cross-section. Also disclosed is an engine including such a valve port. A valve associated with the valve port may be an outwardly-opening valve.

Abstract: An engine has a rotatable crankshaft. A compression piston is received within a compression cylinder and operatively connected to the crankshaft such that the compression piston reciprocates through an intake stroke and a compression stroke during a single rotation of the crankshaft. An expansion piston is received within an expansion cylinder and operatively connected to the crankshaft such that the expansion piston reciprocates through an expansion stroke and an exhaust stroke during a single rotation of the crankshaft. A crossover passage interconnects the compression and expansion cylinders. The crossover passage includes a crossover compression valve and a crossover expansion valve defining a pressure chamber therebetween. A fuel injector is disposed in the pressure chamber of the crossover passage. Fuel injection from the fuel injector into the crossover passage is timed to occur entirely during the compression stroke of the compression piston.

Abstract: Systems and related methods are disclosed that generally involve adjusting the temperature of an air mass to improve the efficiency of an air hybrid engine. In one embodiment, an air management system is provided that includes a heat exchanger, a recuperator, and associated control valves that connect between the air hybrid engine, its exhaust system, and its air tank. The air management system improves the efficiency of the energy transfer to the air tank by compressed air during AC and FC modes and improves the efficiency of the energy transfer from the air tank by compressed air during AE and AEF modes. The improvement in efficiency from the system results in reduced engine and vehicle fuel consumption during driving cycles comprising accelerations, decelerations, and steady-state cruising.

Abstract: An engine has a rotatable crankshaft. A compression piston is received within a compression cylinder and operatively connected to the crankshaft such that the compression piston reciprocates through an intake stroke and a compression stroke during a single rotation of the crankshaft. An expansion piston is received within an expansion cylinder and operatively connected to the crankshaft such that the expansion piston reciprocates through an expansion stroke and an exhaust stroke during a single rotation of the crankshaft. A crossover passage interconnects the compression and expansion cylinders. The crossover passage includes a crossover compression valve and a crossover expansion valve defining a pressure chamber therebetween. A fuel injector is disposed in the pressure chamber of the crossover passage. Fuel injection from the fuel injector into the crossover passage is timed to occur entirely during the compression stroke of the compression piston.

Abstract: A split-cycle engine includes a crankshaft. A compression piston is received within a compression cylinder and operatively connected to the crankshaft such that the compression piston reciprocates through an intake stroke and a compression stroke during a single rotation of the crankshaft. An expansion piston is received within an expansion cylinder and operatively connected to the crankshaft such that the expansion piston reciprocates through an expansion stroke and an exhaust stroke during a single rotation of the crankshaft. A crossover passage interconnects the compression and expansion cylinders. The crossover passage includes a crossover compression (XovrC) valve and a crossover expansion (XovrE) valve defining a pressure chamber therebetween. The crossover compression valve is timed to open when the pressure in the compression cylinder is less than the upstream pressure in the crossover passage at the crossover compression valve.

Abstract: An engine has a rotatable crankshaft. A compression piston is received within a compression cylinder and operatively connected to the crankshaft such that the compression piston reciprocates through an intake stroke and a compression stroke during a single rotation of the crankshaft. An expansion piston is received within an expansion cylinder and operatively connected to the crankshaft such that the expansion piston reciprocates through an expansion stroke and an exhaust stroke during a single rotation of the crankshaft. A crossover passage interconnects the compression and expansion cylinders. The crossover passage includes a crossover compression valve and a crossover expansion valve defining a pressure chamber therebetween. A fuel injector is disposed in the pressure chamber of the crossover passage. Fuel injection from the fuel injector into the crossover passage is timed to occur entirely during the compression stroke of the compression piston.

Abstract: An engine includes a crankshaft rotatable about a crankshaft axis. A compression piston is slidably received within a compression cylinder and operatively connected to the crankshaft. An expansion piston is slidably received within an expansion cylinder and operatively connected to the crankshaft. A crossover passage interconnects the compression and expansion cylinders. The crossover passage includes a crossover expansion (XovrE) valve disposed therein. In at least one of an Engine Firing (EF) mode, an Firing and Charging (FC) mode, and an Air Expander and Firing (AEF) mode of the engine, the timing of the XovrE valve closing is variable to control engine load, and the engine has a residual expansion ratio at XovrE valve closing of 14 to 1 or greater.

Abstract: An engine includes a rotatable crankshaft and an expansion piston slidably received within an expansion cylinder and operatively connected to the crankshaft. A crossover passage including walls connects a source of high pressure gas to the expansion cylinder. A crossover expansion (XovrE) valve is operable to control fluid communication between the crossover passage and the expansion cylinder. The XovrE valve includes a valve head and a valve stem extending from the valve head. A fuel injector operable to inject fuel into the crossover passage includes a plurality of spray holes disposed in a nozzle end and aimed at an at least one target at which fuel emitting from the spray holes is directed to form at least one spray pattern. The at least one target is located above a seated position of the XovrE valve head and between the walls of the crossover passage and the XovrE valve stem.

Abstract: A split-cycle engine includes a crankshaft. A compression piston is received within a compression cylinder and operatively connected to the crankshaft such that the compression piston reciprocates through an intake stroke and a compression stroke during a single rotation of the crankshaft. An expansion piston is received within an expansion cylinder and operatively connected to the crankshaft such that the expansion piston reciprocates through an expansion stroke and an exhaust stroke during a single rotation of the crankshaft. A crossover passage interconnects the compression and expansion cylinders. The crossover passage includes a crossover compression (XovrC) valve and a crossover expansion (XovrE) valve defining a pressure chamber therebetween. The crossover compression valve is timed to open when the pressure in the compression cylinder is less than the upstream pressure in the crossover passage at the crossover compression valve.

Abstract: An engine has a rotatable crankshaft. A compression piston is received within a compression cylinder and operatively connected to the crankshaft such that the compression piston reciprocates through an intake stroke and a compression stroke during a single rotation of the crankshaft. An expansion piston is received within an expansion cylinder and operatively connected to the crankshaft such that the expansion piston reciprocates through an expansion stroke and an exhaust stroke during a single rotation of the crankshaft. A crossover passage interconnects the compression and expansion cylinders. The crossover passage includes a crossover compression valve and a crossover expansion valve defining a pressure chamber therebetween. A fuel injector is disposed in the pressure chamber of the crossover passage. Fuel injection from the fuel injector into the crossover passage is timed to occur entirely during the compression stroke of the compression piston.