Abstract: A split-cycle air hybrid engine includes a rotatable crankshaft. 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 compression (XovrC) valve and a crossover expansion (XovrE) valve defining a pressure chamber therebetween. An air reservoir is operatively connected to the crossover passage. An air reservoir valve selectively controls air flow into and out of the air reservoir. In an Air Expander and Firing (AEF) mode of the engine, the engine has a residual expansion ratio at XovrE valve closing of 15.7 to 1 or greater, and more preferably in the range of 15.7 to 1 and 40.8 to 1.

Abstract: Devices and related methods are disclosed that generally involve the selective deactivation of one or more engine valves. In one embodiment, a split-cycle internal combustion engine is provided in which a high-speed trigger valve is used to fill and drain a hydraulic tappet that forms part of a lost-motion system of an engine valve. A spool valve can be used to selectively disconnect the tappet from the trigger valve, thereby deactivating the associated engine valve (i.e., preventing the engine valve from opening). The devices and methods disclosed herein also have application in conventional internal combustion engines and can be used with inwardly-opening and/or outwardly-opening valves.

Abstract: A split-cycle air-hybrid engine includes a rotatable crankshaft. 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 compression (XovrC) valve and a crossover expansion (XovrE) valve defining a pressure chamber therebetween. An air reservoir is operatively connected to the crossover passage. An air reservoir valve selectively controls air flow into and out of the air reservoir. The engine is operable in an Air Expander and Firing (AEF) mode. In the AEF mode, the pressure in the air reservoir is greater than or equal to approximately 5 bar absolute, preferably greater than or equal to approximately 7 bar absolute, and more preferably greater than or equal to approximately 10 bar absolute.

Abstract: A split-cycle air hybrid engine includes a rotatable crankshaft. 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 compression (XovrC) valve and a crossover expansion (XovrE) valve defining a pressure chamber therebetween. An air reservoir is operatively connected to the crossover passage. An air reservoir valve selectively controls air flow into and out of the air reservoir. In an Air Expander and Firing (AEF) mode of the engine, the engine has a residual expansion ratio at XovrE valve closing of 15.7 to 1 or greater, and more preferably in the range of 15.7 to 1 and 40.8 to 1.

Abstract: Valve actuation systems are disclosed herein that allow valve closing timing to be varied using a lost-motion system. In some embodiments, an actuation system is provided that has a locked configuration in which a bearing element is held in place between first and second valve train components to transmit cam motion to an engine valve. The actuation system also has an unlocked configuration in which the bearing element is permitted to be at least partially ejected from between the first and second valve train components, such that cam motion is not transmitted to the engine valve. A number of valve train configurations are disclosed, including a pushrod with a translating follower, a pushrod with an end-pivoted follower, a center-pivoted rocker, an end-pivoted rocker, and a direct attack valve train with a bucket tappet.

Abstract: A split-cycle air-hybrid engine includes a rotatable crankshaft. 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. An exhaust valve selectively controls gas flow out of the expansion cylinder. A crossover passage interconnects the compression and expansion cylinders. The crossover passage includes a crossover compression (XovrC) valve and a crossover expansion (XovrE) valve therein. An air reservoir is operatively connected to the crossover passage. An air reservoir valve selectively controls air flow into and out of the air reservoir. In an Air Compressor (AC) mode of the engine, the XovrE valve is kept closed during an entire rotation of the crankshaft, and the exhaust valve is kept open for at least 240 CA degrees of the same rotation of the crankshaft.

Abstract: In some embodiments, systems are provided in which electric power generated from a renewable energy source such as a solar or wind power system during low demand periods is used to drive an electric motor which turns an air hybrid split-cycle engine. The split-cycle engine operates in AC mode during this time to compress air into a storage tank. Later, during high demand periods, compressed air stored in the tank and added fuel are fed to the split-cycle engine, which operates in AEF mode. The work generated by the split-cycle engine turns a generator to produce electric power. When the supply of compressed air stored in the storage tank is depleted, the split-cycle engine can operate in an NF mode to serve as a backup generator, or in an FC mode to serve as a backup generator while simultaneously recharging the air storage tank.

Abstract: The present invention provides a valve actuation system comprising a valve train for actuating a valve, the valve train including actuating elements and a valve lash, and a valve lash adjustment system for adjusting the valve lash, wherein the valve train and the valve lash adjustment system do not share any common actuating elements.

Abstract: The present invention provides a valve actuation system comprising a valve train for actuating a valve, the valve train including actuating elements and a valve lash, and a valve lash adjustment system for adjusting the valve lash, wherein the valve train and the valve lash adjustment system do not share any common actuating elements.

Abstract: A split-cycle 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 such that the compression piston reciprocates through intake and compression strokes during a single rotation of the crankshaft. An expansion piston is slidably received within an expansion cylinder and operatively connected to the crankshaft such that the expansion piston reciprocates through expansion and exhaust strokes during a single rotation of the crankshaft. A crossover passage interconnects the expansion and compression cylinders. The crossover passage includes crossover compression (XovrC) and crossover expansion (XovrE) valves defining a pressure chamber therebetween. At least one of the XovrC and XovrE valves is a balanced valve.

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: Devices and related methods are disclosed that generally involve variable actuation of engine valves. In one embodiment, a valve train for a split-cycle internal combustion engine or an air hybrid split-cycle engine is provided that includes a cam phaser, a dwell cam, an adjustable mechanical element for performing a variable valve actuation function, and/or a valve seating control device. The devices and methods disclosed herein also have application in conventional internal combustion engines and can actuate inwardly-opening and/or outwardly-opening valves.

Abstract: Devices and related methods are disclosed that generally involve variable force valve springs for controlling the motion of an engine valve. The force exerted by the valve spring can be adjusted by altering the pressure at which a fluid is supplied to a fluid chamber thereof, by altering the volume of the fluid chamber, and/or by changing the aggregate surface area over which fluid pressure is coupled to the engine valve. Associated fluid control systems are also disclosed herein, as are various methods for adjusting the force of a valve spring based on a variety of engine parameters, such as engine speed, engine load, and/or a combination thereof.

Abstract: Devices and related methods are disclosed that generally involve the selective deactivation of one or more engine valves. In one embodiment, a split-cycle internal combustion engine is provided in which a high-speed trigger valve is used to fill and drain a hydraulic tappet that forms part of a lost-motion system of an engine valve. A spool valve can be used to selectively disconnect the tappet from the trigger valve, thereby deactivating the associated engine valve (i.e., preventing the engine valve from opening). The devices and methods disclosed herein also have application in conventional internal combustion engines and can be used with inwardly-opening and/or outwardly-opening valves.

Abstract: Devices and related methods are disclosed that generally involve actuating an engine valve with a cam having a dwell section. These devices and methods have application in split-cycle engines, air hybrid engines, conventional engines, and/or various combinations thereof. Both inwardly- and outwardly-opening valves can be actuated with the devices and methods disclosed herein. Additional valve train elements are disclosed, including rockers, lost-motion systems, and valve seating control devices.

Abstract: A split-cycle engine includes a rotatable crankshaft. A compression piston is slidably 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 slidably 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 expansion and compression cylinders. The crossover passage includes a crossover compression valve and a crossover expansion valve defining a pressure chamber therebetween. A pilot crossover valve is disposed between the crossover passage and the expansion cylinder.

Abstract: A hydraulic variable compression ratio (VCR) piston for use in an internal combustion engine. The piston is a two-part piston, in which a gudgeon pin carrier slides within an outer sleeve. A variable volume upper chamber is formed between the top of the gudgeon pin carrier and the end of the outer sleeve. When the upper chamber fills with oil, its volume increases, and the overall piston geometry is longer. This reduces the piston clearance in the cylinder and increases cylinder pressure. At a given maximum cylinder pressure or at a given rate of increase of cylinder pressure, oil from the upper chamber is relieved by using a rate-sensitive pressure relief valve.

Abstract: A split-cycle 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 such that the compression piston reciprocates through intake and compression strokes during a single rotation of the crankshaft. An expansion piston is slidably received within an expansion cylinder and operatively connected to the crankshaft such that the expansion piston reciprocates through expansion and exhaust strokes during a single rotation of the crankshaft. A crossover passage interconnects the expansion and compression cylinders. The crossover passage includes crossover compression (XovrC) and crossover expansion (XovrE) valves defining a pressure chamber therebetween. At least one of the XovrC and XovrE valves is a balanced valve.

Abstract: Methods, systems, and devices are disclosed that generally involve split-cycle engines in which a combustion event is initiated in a crossover passage that interconnects a compression cylinder and an expansion cylinder of the split-cycle engine. In one embodiment, the compression piston leads the expansion piston by a phase shift angle so that, for example, a substantial amount of the combustion event can occur in the crossover passage at a constant volume.

Abstract: An engine includes a rotatable crankshaft. 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 an Engine Firing (EF) mode of the engine, the engine has a residual expansion ratio at XovrE valve closing of 10.0 to 1 or greater, and more preferably 15.7 to 1 or greater.