An internal combustion engine system includes an engine with a plurality of pistons housed in respective ones of a plurality of cylinders, an air intake system to provide air to the plurality of cylinders through respective ones of a plurality of intake valves, an exhaust system to release exhaust gas from the plurality of cylinders through respective one of a plurality of exhaust valves. A valve train is provided for cylinder deactivation of a first part of the plurality of cylinders and compression release braking on a second part of the plurality of cylinders.

A rocker arm assembly operable in a first mode and a second mode, the rocker arm assembly selectively opening first and second engine valves based on rotation of a cam shaft having a first cam lobe and a second cam lobe, includes: a rocker shaft; a first rocker arm assembly having a first rocker arm that receives the rocker shaft and rotates around the rocker shaft in the first mode based on engagement with the first cam lobe; a second rocker arm assembly having a second rocker arm that receives the rocker shaft and rotates around the rocker shaft and selectively act on one of the first and second engine valves in the second mode based on selective engagement with the second cam lobe; and a biasing assembly that cooperates with the second rocker arm to bias the second rocker arm to a neutral position.

A rocker arm assembly operable in a first mode and a second mode, the rocker arm assembly selectively opening first and second engine valves based on rotation of a cam shaft having a first cam lobe and a second cam lobe, includes: a rocker shaft; a first rocker arm assembly having a first rocker arm that receives the rocker shaft and rotates around the rocker shaft in the first mode based on engagement with the first cam lobe; a second rocker arm assembly having a second rocker arm that receives the rocker shaft and rotates around the rocker shaft and selectively act on one of the first and second engine valves in the second mode based on selective engagement with the second cam lobe; and a biasing assembly that cooperates with the second rocker arm to bias the second rocker arm to a neutral position.

An apparatus is provided to test valves. The apparatus includes a sensor and a driving mechanism. The driving mechanism is configured to control an external camshaft that is coupled to a valve train of an engine head. The apparatus controls the driving mechanism to control a rotation of the external camshaft that further controls an activation of each valve of the valve train associated with the engine head. The apparatus further controls the sensor to acquire information associated with the activation of each valve of the valve train based on the rotation of the external camshaft. The apparatus further compares the acquired information with pre-stored information, to determine an abnormality in each valve of the valve train, and generates a notification based on the comparison.

An apparatus is provided to test valves. The apparatus includes a sensor and a driving mechanism. The driving mechanism is configured to control an external camshaft that is coupled to a valve train of an engine head. The apparatus controls the driving mechanism to control a rotation of the external camshaft that further controls an activation of each valve of the valve train associated with the engine head. The apparatus further controls the sensor to acquire information associated with the activation of each valve of the valve train based on the rotation of the external camshaft. The apparatus further compares the acquired information with pre-stored information, to determine an abnormality in each valve of the valve train, and generates a notification based on the comparison.

A cam follower is provided. The cam follower includes a polycrystalline diamond element, including an engagement surface. The engagement surface of the polycrystalline diamond element is positioned on the cam follower for sliding engagement with an opposing engagement surface of a cam. The cam includes at least some of a diamond reactive material.

An exhaust passage structure of an internal combustion includes a first merging passage, a second merging passage, and a third merging passage connecting a third gathering portion in which the exhaust gas flowing through the first merging passage and the exhaust gas flowing through the second merging passage gather and a turbine of a turbocharger. The first merging passage and the second merging passage have respective narrowed portions in which passage cross-sectional areas are minimized. When a total value of passage cross-sectional areas of inlets of exhaust ports in one cylinder is set as a reference passage cross-sectional area A, and the passage cross-sectional areas of the narrowed portions of the first merging passage and the second merging passage are set as narrowed cross-sectional areas B, the exhaust passage structure is configured such that the relationship of 0.5≤(B/A)≤1 is established.

A cam follower is provided. The cam follower includes a polycrystalline diamond element, including an engagement surface. The engagement surface of the polycrystalline diamond element is positioned on the cam follower for sliding engagement with an opposing engagement surface of a cam. The cam includes at least some of a diamond reactive material.

A lift-valve assembly, comprising a lift valve within a housing that includes a pressure segment, a mounting segment, a port segment, and a seat segment. The lift-valve assembly may receive a lift valve, and the housing including a valve seat and a biasing spring in a selectively replaceable configuration suitable for use in a conventional internal combustion engine in place of the conventional individual components, actuated by a cam actuating system, and controlling fluid communication between a combustion chamber and both intake and exhaust systems.

A lift-valve assembly, comprising a lift valve within a housing that includes a pressure segment, a mounting segment, a port segment, and a seat segment. The lift-valve assembly may receive a lift valve, and the housing including a valve seat and a biasing spring in a selectively replaceable configuration suitable for use in a conventional internal combustion engine in place of the conventional individual components, actuated by a cam actuating system, and controlling fluid communication between a combustion chamber and both intake and exhaust systems.