An exhaust valve opening apparatus such as for an engine compression braking system includes a rocker shaft for supplying control fluid to an controllable valve and for distributing the control fluid to a primary and second piston arrangement that selectively opens an exhaust valve in response to the control fluid being pressurized.

A compression release type engine brake includes an exhaust rocker arm including a roller which is mounted at one end portion thereof, and the exhaust rocker arm rotating around a rocker arm shaft by the rotation of the exhaust cam, a valve bridge disposed on the other end portion of the exhaust rocker arm and connected to an exhaust valve, a brake module mounted between the exhaust rocker arm and the valve bridge, contacting with the roller and the brake cam lobe according to inflow of selectively supplied operation oil to open the exhaust valve by the exhaust cam, and the brake module including a reset valve closing operation oil inside therein, and a reset piston slidably mounted on the second end portion of the exhaust rocker arm and protruding out of the second end portion of the exhaust rocker arm according to the supply of reset oil to push the reset valve to expel the operation oil in the brake module outwards.

A valve rocker arm assembly, a variable air distribution mechanism, and an engine are provided according to the present disclosure. The valve rocker arm assembly includes: an oil inlet hose; a rocker arm shaft, an oil drain channel, an oil return groove, and a first oil path being provided in the rocker arm shaft, the oil drain channel being communicated with the oil return groove by means of the first oil path; a first rocker arm and a second rocker arm rotatably connected onto the rocker arm shaft, a piston cavity, an oil inlet path, an oil drain path and a piston being provided on the second rocker arm; a one-way opening device provided in the oil inlet path and/or the oil inlet hose; and a control valve connected to the oil drain channel.

A cylinder head includes a hydraulic lash adjuster attachment portion provided with a hydraulic lash adjuster bore in which a hydraulic lash adjuster is inserted; a main oil provided at a position away from the hydraulic lash adjuster bore; a connection oil passage which connects the hydraulic lash adjuster bore and the main oil passage; and a side wall that defines a radially outer portion of the hydraulic lash adjuster bore. The side wall includes a first side wall portion and a second side wall portion that is positioned closer to an opening of the hydraulic lash adjuster bore than the first side wall portion is. A thickness of the second side wall portion is greater than a thickness of the first side wall portion.

A self-resetting single-valve double-piston hydraulic drive device and method for an overhead cam engine is disclosed. A primary driving piston and a secondary driving piston are respectively provided on a rocker arm body and a valve bridge body. The secondary driving piston is connected to an exhaust valve. When the drive control valve opens, the primary driving piston and the secondary driving piston realize a hydraulic linkage, during a drive lift, the secondary driving piston opens the exhaust valve. At the beginning of the positive-power lift, the secondary driving piston is automatically reset. When the control valve is closed, during the drive lift of an integrated cam, the primary driving piston absorbs the drive lift of an integrated cam assembly, the rocker arm body and the bridge body do not move, and the drive lift of the integrated cam is not transmitted to the exhaust valve.

A variable valve timing assembly is provided for extending a duration of an intake valve opening. The variable valve timing assembly includes an intake rocker mounted on a pedestal and operable by a cam lobe to open and close the intake valve. The intake rocker includes a lever extension, and a holding member in the pedestal is lockable in position by a hydraulic circuit in the pedestal to contact the lever extension of the intake rocker and hold the intake valve in the open position. A reset pin in the pedestal is actuatable by the cam lobe to release the holding member to allow the intake valve to close.

An engine system and valvetrain can comprise a rocker shaft combined with a first block, a first cylinder deactivation oil control valve in the first block, a second cylinder deactivation oil control valve in the first block. Also, a second block can be combined with the rocker shaft with a third cylinder deactivation oil control valve and an early exhaust valve opening oil control valve in the second block. The rocker shaft can comprise oil infeeds and oil outfeeds configured for supplying hydraulic pressure to the first and second blocks, the blocks can distribute the pressure to the control valves, and the blocks can return pressure to the rocker shaft. Intake and exhaust rocker arms can receive the returned pressure to actuate valves, and the rockers arms can be arranged line-to-line with no overlap during motion.

A rocker arm mechanism includes a rocker arm shaft, a rocker arm, a valve clearance adjuster, a valve train, and a control valve. The rocker arm is rotatably disposed on the rocker arm shaft. The valve train includes a valve bridge. The rocker arm is provided with a plunger chamber. The valve clearance adjuster includes a hydraulic tappet slidably disposed in the plunger chamber. The plunger chamber is supplied with oil through an oil supply passage. The control valve is configured to open or close the oil supply passage. When the control valve opens the oil supply passage, the hydraulic tappet can abut against the valve bridge and eliminate the clearance between the valve bridge and the hydraulic tappet.

Valve actuation mechanisms are provided for hydraulically controlling cylinder deactivation and variable valve lift operations. The valve actuation mechanisms include a hydraulic circuit that is selectively pressurized to secure a reciprocating member in an extended position to transfer motion from the camshaft lobe to the intake valves or exhaust valves, and vented to allow the reciprocating member to reciprocate.

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.