The disclosure concerns an internal combustion engine comprising an exhaust camshaft, an intake camshaft, a turbocharger, and a control system. The turbocharger comprises a compressor. A timing of the exhaust camshaft and a timing of the intake camshaft are controllable by the control system, which is configured to: store a compressor map related to the compressor, store a reference area within the compressor map, and determine at least two parameters. In response to the at least two parameters indicating that a current operational point of the compressor is outside the reference area, the control system changes the timing of the exhaust camshaft to advance closing of the exhaust valve, and the timing of the intake camshaft to delay opening of the intake valve.

The disclosure concerns an internal combustion engine comprising an exhaust camshaft, an intake camshaft, a turbocharger, and a control system. The turbocharger comprises a compressor. A timing of the exhaust camshaft and a timing of the intake camshaft are controllable by the control system, which is configured to: store a compressor map related to the compressor, store a reference area within the compressor map, and determine at least two parameters. In response to the at least two parameters indicating that a current operational point of the compressor is outside the reference area, the control system changes the timing of the exhaust camshaft to advance closing of the exhaust valve, and the timing of the intake camshaft to delay opening of the intake valve.

Methods and systems are described for enhanced engine friction generation. The enhanced engine friction generation improves the effectiveness of vehicle braking in deceleration fuel cut-off driving conditions by using engine vacuum and backpressure to temporarily increase engine pumping losses, thereby increasing powertrain drag and increasing deceleration torque to the wheels. The engine vacuum and backpressure may be created by changing the duration of the intake and/or exhaust valves. The system includes a processor and a non-transitory computer-readable storage medium storing instructions that, when executed by the processor, cause the processor to perform operations comprising adjusting an intake valve time duration or an exhaust valve time duration to increase engine friction to enhance mechanical friction on a drivetrain of a vehicle.

An internal combustion engine and a method of controlling an internal combustion engine are provided, that are more efficient than existing engines. The internal combustion engine includes a combustion chamber, and the engine is configurable to operate in: a compressionless operating mode where the engine is driven by combustion of fuel and oxidant in the combustion chamber without compression of the fuel and oxidant; and a compression generating operating mode where the engine is used to compress fluid in the combustion chamber.

A compression-release engine brake system operating an exhaust valve of an engine during a compression-release engine braking operation. The compression-release brake system comprises an exhaust rocker arm and a brake reset device disposed in a reset bore formed in the exhaust rocker arm. The brake reset device comprises a reset check valve, a slider-piston slidably disposed in the reset bore and an external slider bias spring biasing the piston foot away from the brake reset device. The external slider bias spring is disposed outside the reset bore and around the piston-slider. The brake reset device permits pressurized hydraulic fluid to flow from a supply conduit to a reset conduit to supply a brake actuation piston when the reset check valve is open. The actuation piston extends and engages the exhaust valve toward the end of a compression stroke of the internal combustion engine, and the brake reset device resets.

A compression-release engine brake system operating an exhaust valve of an engine during a compression-release engine braking operation. The compression-release brake system comprises an exhaust rocker arm and a brake reset device disposed in a reset bore formed in the exhaust rocker arm. The brake reset device comprises a reset check valve, a slider-piston slidably disposed in the reset bore and an external slider bias spring biasing the piston foot away from the brake reset device. The external slider bias spring is disposed outside the reset bore and around the piston-slider. The brake reset device permits pressurized hydraulic fluid to flow from a supply conduit to a reset conduit to supply a brake actuation piston when the reset check valve is open. The actuation piston extends and engages the exhaust valve toward the end of a compression stroke of the internal combustion engine, and the brake reset device resets.

The invention concerns a method for controlling a compression release brake mechanism in an combustion engine comprising an air inlet system and an exhaust manifold connected to a turbocharger provided with a variable turbine geometry (VTG) turbine, said exhaust manifold further comprising an exhaust gas recirculation (EGR) channel for recirculation of exhaust gas towards the air inlet system, wherein said turbine is further connected to a back pressure valve (BPV) provided in an exhaust channel, the method comprising determining a desired exhaust manifold gas pressure level on the basis of a measured engine speed and a desired braking torque; continuously monitoring a set of control parameters, including at least two of cylinder pressure, exhaust manifold pressure, turbine speed and turbine expansion ratio; controlling said BPV and said VTG by said control parameters, to drive one of the control parameters to a set maximum level; and controlling the EGR by said control parameters in a closed loop to allow exhaust gas to recirculate towards the air inlet system while driving a second of the set of control parameters to a set maximum level.

An engine brake rocker arm assembly is operable in an engine drive mode and an engine braking mode and selectively opens first and second exhaust valves. The engine brake rocker arm assembly includes an exhaust rocker arm configured to rotate about a rocker shaft, an engine brake capsule assembly movable between (i) a locked position configured to perform an engine braking operation, and (ii) an unlocked position that does not perform the engine braking operation, and a hydraulically controlled actuator assembly configured to selectively move the engine brake capsule assembly between the first and second positions.

An engine brake rocker arm assembly is operable in an engine drive mode and an engine braking mode and selectively opens first and second exhaust valves. The engine brake rocker arm assembly includes an exhaust rocker arm configured to rotate about a rocker shaft, an engine brake capsule assembly movable between (i) a locked position configured to perform an engine braking operation, and (ii) an unlocked position that does not perform the engine braking operation, and a hydraulically controlled actuator assembly configured to selectively move the engine brake capsule assembly between the first and second positions.

An engine braking system includes a camshaft, a follower, an exhaust armature, a lever, and a hydraulically actuated piston. The camshaft includes at least one cam. The cam has a lobe and a brake bump. The follower engages the cam. The exhaust armature is coupled to the follower. The lever is coupled to the exhaust armature. The hydraulically actuated piston moves the lever. Hydraulic actuation of the piston causes a change in lash distance between the cam and the follower. In an engine brake mode, the follower contacts the cam throughout rotation of the cam.