An internal combustion engine includes an electro-hydraulic system for variable actuation of intake valves where each cylinder has two intake valves, associated with two intake conduits. A first conduit is generates within the cylinder a tumble motion of airflow introduced therein, when the intake valve associated thereto is at least partially opened. The second intake conduit generates within the cylinder a swirl motion of airflow introduced therein when the second intake valve is at least partially opened. A controller of controls one or more control valves to open only one of the intake valves of each cylinder in a condition of reduced engine operation, below a predetermined load and/or a predetermined speed of the engine, and to always open both intake valves in the remaining conditions of engine operation. The first intake valve is the only valve to be opened in the reduced engine operation condition.

The variable valve actuating device (20) comprises a switch pin (53) slidably received in the valve lifter (24) so as to selectively abut the end surface of the valve stem as the valve lifter is actuated by the cam. The device further comprises a first spring retainer (36) attached to an intermediate part of the valve stem (32) to engage a first valve spring (35), and a second spring retainer (44) slidably engaged by an end part of the valve stem to engage a second valve spring (43). The valve stem is provided with a stem end (39) which is enlarged with respect to a part of the valve stem slidably engaging the second spring retainer so as to define a shoulder surface (40a) that engages the second spring retainer against a spring force of the second valve spring.

The variable valve actuating device (20) comprises a switch pin (53) slidably received in the valve lifter (24) so as to selectively abut the end surface of the valve stem as the valve lifter is actuated by the cam. The device further comprises a first spring retainer (36) attached to an intermediate part of the valve stem (32) to engage a first valve spring (35), and a second spring retainer (44) slidably engaged by an end part of the valve stem to engage a second valve spring (43). The valve stem is provided with a stem end (39) which is enlarged with respect to a part of the valve stem slidably engaging the second spring retainer so as to define a shoulder surface (40a) that engages the second spring retainer against a spring force of the second valve spring.

A rocker arm assembly for an engine is configured to fit about a pivot shaft that extends along a central axis. The assembly includes an intermediate shaft configured to be rotatably disposed about the pivot shaft. A cam-side arm is pivotable about the central axis and is configured to be driven by a cam. A valve-side arm is pivotable about the central axis and relative to the cam-side arm, and is configured to convert rotation of the rocker arm assembly about the central axis into operation of an engine valve. An annular compressible fluid chamber is disposed between the intermediate shaft and the valve-side arm. When the cam-side arm and the intermediate shaft are engaged, pivoting of the cam-side arm compresses fluid within the chamber, causing corresponding pivoting of the valve-side arm and operation of the valve. The fluid provides hydraulic lash adjustment.

An internal combustion engine includes an electro-hydraulic system for variable actuation of intake valves where each cylinder has two intake valves, associated with two intake conduits. A first conduit is generates within the cylinder a tumble motion of airflow introduced therein, when the intake valve associated thereto is at least partially opened. The second intake conduit generates within the cylinder a swirl motion of airflow introduced therein when the second intake valve is at least partially opened. A controller of controls one or more control valves to open only one of the intake valves of each cylinder in a condition of reduced engine operation, below a predetermined load and/or a predetermined speed of the engine, and to always open both intake valves in the remaining conditions of engine operation. The first intake valve is the only valve to be opened in the reduced engine operation condition.

A system includes an engine with a plurality of pistons housed in respective ones of a plurality of cylinders, an air intake system provides 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 one of a plurality of exhaust valves, and a controller coupled to a sensor to control a switching tappet for compression release braking. Alternatively to a tappet, the system includes a roller finger follower controlling an opening and closing timing of exhaust valves, the roller finger follower has an inner roller follower arm adjacent an outer sliding follower, and a controller that in response to an engine braking request locks the inner roller follower arm with the outer sliding follower to contact a second cam lobe and open the exhaust valve during a compression stroke of the cylinder.

A system includes an engine with a plurality of pistons housed in respective ones of a plurality of cylinders, an air intake system provides 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 one of a plurality of exhaust valves, and a controller coupled to a sensor to control a switching tappet for compression release braking. Alternatively to a tappet, the system includes a roller finger follower controlling an opening and closing timing of exhaust valves, the roller finger follower has an inner roller follower arm adjacent an outer sliding follower, and a controller that in response to an engine braking request locks the inner roller follower arm with the outer sliding follower to contact a second cam lobe and open the exhaust valve during a compression stroke of the cylinder.

A system includes an engine with a plurality of pistons housed in respective ones of a plurality of cylinders, an air intake system provides 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 one of a plurality of exhaust valves, and a controller coupled to a sensor to control a switching tappet for compression release braking. Alternatively to a tappet, the system includes a roller finger follower controlling an opening and closing timing of exhaust valves, the roller finger follower has an inner roller follower arm adjacent an outer sliding follower, and a controller that in response to an engine braking request locks the inner roller follower arm with the outer sliding follower to contact a second cam lobe and open the exhaust valve during a compression stroke of the cylinder.

An engine roller lifter for use in a leak-valvetrain of an internal combustion engine includes a body, a roller and an anti-rotation plug. The body includes an outer peripheral surface configured for sliding movement in a bore provided in the engine. The bore is supplied oil by an oil passage communicating therewith. The body defines an opening. The roller bearing is rotatably mounted to the body and is configured for rolling contact with an engine camshaft. The anti-rotation plug is received at the opening and has a plug body including an anti-rotation protrusion that extends radially beyond an outer peripheral surface of the plug body. The anti-rotation plug can be staked into the opening of the body.

An engine roller lifter for use in a leak-valvetrain of an internal combustion engine includes a body, a roller and an anti-rotation plug. The body includes an outer peripheral surface configured for sliding movement in a bore provided in the engine. The bore is supplied oil by an oil passage communicating therewith. The body defines an opening. The roller bearing is rotatably mounted to the body and is configured for rolling contact with an engine camshaft. The anti-rotation plug is received at the opening and has a plug body including an anti-rotation protrusion that extends radially beyond an outer peripheral surface of the plug body. The anti-rotation plug can be staked into the opening of the body.