Aspects of the present disclosure are directed to valve clearance adjustment systems and related methods that can be used to quickly and easily establish and accurately fix a desired gap between valve stems and associated valve adjustment screws attached to rocker arms, such as may be used with intake valves, exhaust valves, and fuel-injection mechanisms, among others, within, e.g., an internal combustion engine. Various alternative implementations and related methods are provided.

A rocker arm includes an outer arm defining a stop aperture with a stop surface; an inner arm which selectively pivots relative to the outer arm; a latching mechanism which switches the rocker arm between a coupled state in which the inner arm is prevented from pivoting relative to the outer arm in a first direction and a decoupled state in which the inner arm pivots relative to the outer arm; a lost motion spring which biases the inner arm to pivot relative to the outer arm in a second direction which is opposite from the first direction; and a stop pin fixed to the inner arm and extending into the stop aperture such that the stop pin is circumferentially surrounded by the stop surface and such that the stop pin within the stop aperture limits the extent to which the inner arm pivots relative to the outer arm.

A hydraulic valve brake for a hydraulic valve drive of an internal combustion engine is provided. The valve brake includes a housing with a housing wall and with a housing base, and includes a piston which moves axially in the housing and one end side of which, together with the housing wall and the housing base, delimits a hydraulic pressure chamber and the other end side of which actuates a gas exchange valve. The housing wall is perforated in the region of the pressure chamber by one or more overflow openings, the opening cross sections of which are controlled by a control edge, which delimits the end side at the pressure chamber side, of the piston. In this case, it is the intention for the axial distance (h) between the control edge of the piston, when the latter is fully retracted into the housing, and the housing base to be set by a spacer of predetermined thickness (d).

A fast acting valve train system for valve deactivation is provided that includes an actuator together with a switchable rocker arm. The actuator, controlled by the engine control unit and mounted to a structural housing, contains an actuator pin that retracts or extends facilitating either a deactivation or reactivation valve event. The switchable rocker arm is a two arm design that includes cam side and valve side arms that are coupled together with a locking mechanism assembly that interfaces with the actuator pin. The system is capable of fast switching times to meet the increased demands of cylinder deactivation systems.

A hydraulic valve brake for a hydraulic valve drive of an internal combustion engine is provided. The valve brake includes a housing with a housing wall and with a housing base, and includes a piston which moves axially in the housing and one end side of which, together with the housing wall and the housing base, delimits a hydraulic pressure chamber and the other end side of which actuates a gas exchange valve. The housing wall is perforated in the region of the pressure chamber by one or more overflow openings, the opening cross sections of which are controlled by a control edge, which delimits the end side at the pressure chamber side, of the piston. In this case, it is the intention for the axial distance (h) between the control edge of the piston, when the latter is fully retracted into the housing, and the housing base to be set by a spacer of predetermined thickness (d).

An internal combustion engine system includes an engine with a plurality of pistons housed in respective ones of a plurality of cylinders. A valve train is provided for opening and closing intake and exhaust valves of the cylinders during nominal engine operations. The valve train is also configured for cylinder deactivation and to provide one or more selected lift profiles for opening and closing of the intake and/or exhaust valves.

A fast acting valve train system for valve deactivation is provided that includes an actuator together with a switchable rocker arm. The actuator, controlled by the engine control unit and mounted to a structural housing, contains an actuator pin that retracts or extends facilitating either a deactivation or reactivation valve event. The switchable rocker arm is a two arm design that includes cam side and valve side arms that are coupled together with a locking mechanism assembly that interfaces with the actuator pin. The system is capable of fast switching times to meet the increased demands of cylinder deactivation systems.

A switchable finger follower, including an inner lever and an outer lever. The outer lever is mounted for pivoting movement to the inner lever. A coupling device is located on one of the inner or outer levers and has a coupling pin arranged to move between a locking position, in which the inner and outer levers are connected together for movement in an activation direction, and an unlocked position, in which the inner lever is pivotable relative to the outer lever. A coupling projection is located on the other of the inner or outer lever. The coupling pin engages beneath a coupling surface of the projection in the locking position, and a stop surface of the projection contacts a second stop surface on the one of the inner lever or the outer lever. The second stop surface is located on a removable shim that is replaceable for lash adjustment.

A method for setting lash on a switching rocker arm assembly includes providing a rocker arm having (i) an outer arm having a first outer side arm and a second outer side arm, the outer arm defining an opening, (ii) an inner arm disposed between the first and second outer side arms, (iii) a roller follower that selectively engages a cam, the roller follower mounted about a bearing axle that extends through the opening. A zero lash shim is inserted into a gap defined between the bearing axle and the outer arm at the opening. The rocker arm is installed into the valvetrain with the master tip cap. Lash is measured between the cam and the roller follower. The rocker arm and the master tip cap is removed. A select fit valve tip cap is installed based on the master tip cap and the measured lash.

A latch assembly can comprise a main latch pin assembly comprising a first diameter on a first main pin face, and a secondary latch piston comprising a second diameter on a secondary piston face. The secondary latch piston can be configured to selectively act on the main latching pin assembly. The main latch pin assembly can be biased to oppose the secondary latch piston. The first diameter can be greater than the second diameter. A rocker arm assembly can comprise the latch assembly. A primary arm can be configured to receive the main latch pin assembly. A secondary arm can be configured to receive the secondary latch piston.