An actuation apparatus for actuating a component of a switchable valve train device of an internal combustion engine includes: a support body for mounting on a cylinder head cover of the internal combustion engine; an actuation lever mounted to the support body for pivotal movement of the actuation lever between a first position for actuation of the component and a second position for allowing de-actuation of the component; and a biasing means for urging the actuation lever from the second position towards the first position. In use, the biasing means becomes biased when an actuation source causes the actuation lever to pivot to the second position. When the actuation source attempts to actuate the component when the component is non-actuatable, the biasing means causes the actuation lever to pivot from the second position to the first position, thereby to actuate the component when the component becomes actuatable again.

A rocker arm swingably supported by an arm shaft and operating a valve by rotation of a cam includes an arm body part including a bearing portion supported by the arm shaft, a cam-side arm portion extending from the bearing portion toward a first side, and a valve-side arm portion extending from the bearing portion toward a second side, an arch part extending over the bearing portion and connecting the cam-side arm portion and the valve-side arm portion, and a lightweight part disposed in a space defined between the arm body part and the arch part and having a reduced weight compared with a case where the space is filled with the same material at the same thickness as the arch part.

An opposed-piston engine optionally contains an ignition system that is at least partially contained within the combustion chamber to enhance the combustion efficiency of a fuel-air mixture within the combustion system. More specifically, the ignition system contains at least one spark plug having an elongated center electrical delivery electrode, and, an elongated ground electrode. Accordingly, the elongated electrodes extend from an area adjacent to the inner periphery of the cylinder to a radially central area within the combustion chamber. Yet further, a cooling jacket is incorporated to provide cooling of the spark plug.

A rocker arm assembly selectively opening first and second engine valves. The assembly includes a rocker arm and a valve bridge operably associated with the rocker arm and including a main body and a lever rotatably coupled to the main body. The main body is configured to engage the first engine valve, and the lever is configured to engage the second engine valve.

A valve train assembly includes: at least one dual body rocker arm having a first body, a second body, and a latching arrangement for latching and unlatching the first body and the second body, the latching arrangement being biased to an unlatched configuration; and an actuator arrangement external to the rocker arm for controlling the latching arrangement, the actuator arrangement being arranged so that a default setting thereof is to cause the latching arrangement to be in a latched configuration.

A valve train assembly includes at least a number of exhaust valves; at least one camshaft with at least a pair of a primary lift cam and an engine brake lift cam. A number of rocker arms each include a cam follower for following one of the primary lift cam and the engine brake lift cam. One rocker arm includes a cam follower following an engine brake lift cam. The rocker arm is provided with an engine brake capsule. Various biasing assemblies are disclosed that cooperate with one of the rocker arms of which the cam follower follows an engine brake lift cam to accommodate mechanical lash.

A summation rocker system is disclosed for acting on the end of a stem of a poppet valve (16) in dependence upon the combined lifts of a first and a second cam profile defined by different cam lobes (14, 22) of a concentric camshaft (46). The system comprises a first rocker (12) mounted on a pivot shaft (18) and having a first follower (44) to contact the first cam profile and an end acting on the valve (16) to displace the valve (16) by an amount dependent upon the lift of the first cam profile, a rocker shaft (24) to be fixedly mounted on the engine, and a second rocker (20) pivotable about the rocker shaft (24), the second rocker (20) having a second follower (48) to contact the second cam profile and acting to displace the pivot shaft (18) of the first rocker (12) in dependence of the lift of second cam profile. The rocker shaft (24) intersects a plane containing the axis of the pivot shaft (18) and the end of the first rocker (12) acting on the valve stem, and the first rocker (12) includes a cut-out (26) for receiving the rocker shaft (24), which cut-out (26) is configured and dimensioned to prevent the rocker shaft (24) from interfering with movement of the first rocker (12).

A rocker arm assembly having a rocker arm including a pair of sidewalls, each sidewall defining a support aperture, a rocker arm support including a pair of opposed bearing support arms, each bearing support arm being disposed within a corresponding support aperture of the rocker arm and defining a lubrication groove extending along an outer surface thereof, and a pair of radial roller bearings, each including an inner cup, an outer cup, and a plurality of rollers disposed therebetween, wherein each radial roller bearing is disposed both on a corresponding bearing support arm and within a corresponding support aperture.

Methods and systems are provided for a valve bridge of an internal combustion engine. In one example, a valve bridge comprises a first arm, a longitudinally opposing second arm, and one or more interior walls forming a passage extending laterally through at least a portion of the valve bridge, the passage disposed between the first arm and second arm and forming a first main opening and an opposing, second main opening. A central support structure is disposed within the passage and is formed by the one or more interior walls.

An actuation apparatus for actuating a component of a switchable valve train device of an internal combustion engine includes: a support body for mounting on a cylinder head cover of the internal combustion engine; an actuation lever mounted to the support body for pivotal movement of the actuation lever between a first position for actuation of the component and a second position for allowing de-actuation of the component; and a biasing means for urging the actuation lever from the second position towards the first position. In use, the biasing means becomes biased when an actuation source causes the actuation lever to pivot to the second position. When the actuation source attempts to actuate the component when the component is non-actuatable, the biasing means causes the actuation lever to pivot from the second position to the first position, thereby to actuate the component when the component becomes actuatable again.