Methods and systems are provided for a prechamber. In one example, the prechamber comprises one or more valves for optionally adjusting gas flow therethrough. The one or more valves may allow pre-chamber and combustion chamber settings to be modified, thereby enhancing combustion operating parameters.

An internal combustion engine includes a hollow cylinder, a piston within the hollow cylinder, and a cylinder head. A base valve assembly at a base of the hollow cylinder permits or restricts fluid flow from an intake manifold into a sub-chamber below the piston. The piston includes at least one intake port connecting a combustion chamber above the piston with the sub-chamber, and a transfer valve that opens and closes the at least one intake port. When the transfer valve opens the at least one intake port, fluid is permitted to flow from the sub-chamber to the combustion chamber. The internal combustion engine operates according to a four-stroke piston cycle, wherein multiple intake stages are provided. The intake stages may include intake of air into the sub-chamber during a compression stroke, transfer of air from the sub-chamber to the combustion chamber during a power stroke, intake of air-fuel mixture into the sub-chamber during an exhaust stroke, and transfer of air-fuel mixture from the sub-chamber to the combustion chamber during an intake stroke.

A system and associated methods for controlling valve motion in internal combustion engines provide a pulsing component for energizing a solenoid control valve in pulsatile fashion to cause a transient pressure change in a hydraulic network linking the control valve to a common, paired set of intake and exhaust main event deactivation mechanisms, which may be provided in respective valve bridges. The pressure change results in hydraulic deactivation of main event motion of the exhaust valve while avoiding deactivation of main intake event motion and thereby preserving intake main event valve motion, and supporting use of the intake main event motion for additional braking or other operations. The systems and methods are particularly suited for engine environments that employ cylinder deactivation (CDA) combined with high-power density (HPD) engine braking.

A system and associated methods for controlling valve motion in internal combustion engines provide a pulsing component for energizing a solenoid control valve in pulsatile fashion to cause a transient pressure change in a hydraulic network linking the control valve to a common, paired set of intake and exhaust main event deactivation mechanisms, which may be provided in respective valve bridges. The pressure change results in hydraulic deactivation of main event motion of the exhaust valve while avoiding deactivation of main intake event motion and thereby preserving intake main event valve motion, and supporting use of the intake main event motion for additional braking or other operations. The systems and methods are particularly suited for engine environments that employ cylinder deactivation (CDA) combined with high-power density (HPD) engine braking.

A decompression shaft (56) of a decompression device (50) includes an engagement pin (53) that is guided by a guide groove (51a) formed in a decompression weight (51), a decompression cam (54) that is provided on one cam surface of an intake valve cam (25c) and an exhaust valve cam (25b) so as to advance and retreat, and a connection portion (55) that connects the engagement pin (53) and the decompression cam (54). The decompression weight (51) is formed with a rotation restricting groove (51e) that restricts rotation of the decompression shaft (56) when a force acts in a direction in which the decompression cam (54) moves on the decompression shaft (56) from an advanced position to a retracted position when an engine (E) is stopped and that is continuous with the guide groove (51a).

A method for starting a compression ignition engine having at least one cylinder with a reciprocating piston located therein, an intake valve configured to control the intake of air to an intake port of the cylinder and an exhaust valve configured to control the expulsion of gas from an exhaust port of the cylinder. The method includes the steps of: cranking the engine, conditioning intake air at the intake port of the cylinder to raise the temperature of air in the cylinder, controlling a valve timing the intake valve and/or the exhaust valve to allow the piston to compress the air within the cylinder, thereby increasing the temperature of the air within the cylinder, and injecting fuel into the cylinder when the air within the cylinder has been heated to a temperature sufficient to support compression ignition of a gasoline and air mixture within the cylinder.

A method for starting a compression ignition engine having at least one cylinder with a reciprocating piston located therein, an intake valve configured to control the intake of air to an intake port of the cylinder and an exhaust valve configured to control the expulsion of gas from an exhaust port of the cylinder. The method includes the steps of: cranking the engine, conditioning intake air at the intake port of the cylinder to raise the temperature of air in the cylinder, controlling a valve timing the intake valve and/or the exhaust valve to allow the piston to compress the air within the cylinder, thereby increasing the temperature of the air within the cylinder, and injecting fuel into the cylinder when the air within the cylinder has been heated to a temperature sufficient to support compression ignition of a gasoline and air mixture within the cylinder.

A method for operating an internal combustion engine having a cylinder, an intake valve, an air pipe, and a valve element disposed in the air pipe, includes detecting a signal for causing a fuel supply of the cylinder to switch off. The valve element is moved out of a first position into a second position triggering a lower flow cross-section while the fuel supply is still activated, where a first cam for actuating the intake valve is allocated to the intake valve. While the fuel supply is still activated, switching from the first cam to a second cam and via the second cam the intake valve is actuated such that the intake valve causes a reduced air intake. An exhaust cam shaft for actuating an exhaust valve is set in an advance direction such that a valve intersection of the intake valve and of the exhaust valve ceases.

A method for operating an internal combustion engine having a cylinder, an intake valve, an air pipe, and a valve element disposed in the air pipe, includes detecting a signal for causing a fuel supply of the cylinder to switch off. The valve element is moved out of a first position into a second position triggering a lower flow cross-section while the fuel supply is still activated, where a first cam for actuating the intake valve is allocated to the intake valve. While the fuel supply is still activated, switching from the first cam to a second cam and via the second cam the intake valve is actuated such that the intake valve causes a reduced air intake. An exhaust cam shaft for actuating an exhaust valve is set in an advance direction such that a valve intersection of the intake valve and of the exhaust valve ceases.

Systems, apparatuses and methods are disclosed that include an internal combustion engine including a plurality of cylinders operable by a valve actuation mechanism including a lifting mechanism having a compression brake valve profile configured to selectively lift the exhaust valves on a downstroke of the cylinders in response to a cranking condition of the internal combustion engine, wherein the compression braking valve profile is phased to the upstroke of the pistons.