A bidirectional latch pin assembly can comprise a housing portion comprising a latch port. A latch pin in the latch port can comprise a stepped nose extending from a body portion. The stepped nose can comprise a first step and a second step. A spring can be biased against a guide mounted in the latch port and the spring can be configured to bias the latch pin to a first position extending the first step out of the latch port. A first actuation assembly can be configured to move the latch pin to a second position extending the first step and the second step out of the latch port. A second actuation assembly can be configured to move the latch pin to a third position pulling the first step and the second step into the latch port. A switchable rocker arm and a valvetrain assembly can be formed therewith.

A rocker arm mechanism of an engine, a system and a method for two-stroke engine brake are provided. The rocker arm mechanism includes a first rocker arm, a second rocker arm and a connection mechanism. One end of the first rocker arm and one end of the second rocker arm is rotatably connected to a shaft, the other end of the first rocker arm is close to a valve of the engine, while the other end of the second rocker arm is close to a cam. The connection mechanism includes a connecting piston and a linkage mechanism. The connecting piston is disposed in the first rocker arm or the second rocker arm, the linkage mechanism is rotatably connected to one end of the connecting piston. The rocker arm mechanism may be used for engine cylinder deactivation and engine brake.

A method for controlling a valve arrangement for an internal combustion engine, the valve arrangement including a piston arrangement comprising a piston having a piston end portion facing an inlet valve of the valve arrangement. The method includes receiving a signal indicative of a temperature level of an exhaust gas after treatment system and when the signal indicates a temperature level below a predetermined threshold level: advancing an exhaust event of the internal combustion engine; and controlling the piston arrangement for reducing the distance between the piston end portion and the inlet valve before the internal combustion engine assumes an air intake event.

Systems and related methods include a rocker arm having integrated components, including a lost motion actuator piston and components for resetting the lost motion actuator piston to provide normal valve closing or late valve closing. Selective reset is facilitated by a reset piston and a blocking piston disposed in a hydraulic circuit including a reset passage. In a non-resetting mode of operation, the blocking piston may block oil flow within the reset passage, regardless of the position of the reset piston, which facilitates late valve closing. An alternative embodiment includes a blocking sleeve disposed concentrically relative to the reset piston.

An actuator for actuating valve-lift modes of a valve train assembly of an internal combustion engine. The valve train assembly is capable of being switched between a first valve-lift mode and a second valve-lift mode. The actuator includes a first body and a second body. The second body is mounted for reciprocal movement with respect to the first body between a first position to cause the first valve-lift mode and a second position to cause the second valve-lift mode. The actuator includes a third body supported by the second body, the third body for moving a first component of the valve train assembly to cause the second valve-lift mode. The third body is moveable relative to the second body. The actuator includes a first biaser for biasing the third body away from the second body towards the first component of the valve train assembly.

A rocker arm includes an outer arm defining a bore; an inner arm which pivots relative to the outer arm, the inner arm defining a stop surface; a lost motion spring which biases the inner arm to pivot relative to the outer arm in a first direction; and a lock pin that slides within the bore between a coupled position in which the lock pin prevents the inner arm from pivoting relative to the outer arm past a predetermined position in a second direction which is opposite of the first direction and a decoupled position in which the lock pin permits the inner arm to pivot relative to the outer arm past the predetermined position in the second direction; such that the lock pin and the stop surface act together to limit the extent to which the inner arm pivots relative to the outer arm in the first direction.

Methods and systems are provided for an engine oil system of a cylinder head. In one example, an engine oil system may include a first oil gallery and a second oil gallery fluidly coupled to each other via a plurality of oil chambers. Each oil chamber includes a plug, and one or more of the plugs may include a slot shaped to direct a flow of engine oil from a solenoid valve to the second oil gallery.

A control device for an internal combustion engine is configured to: execute a first decompression operating processing such that a decompression operating state is selected in a first engine speed region that passes in the course of engine stop; execute a decompression stop processing such that a switching from the decompression operating state to a decompression stop state is performed in the course of the engine stop after passage of the first engine speed region; when a temperature correlation value is greater than or equal to a threshold value upon an engine start-up request, execute a second decompression operating processing such that the decompression operating state is selected in a second engine speed region that passes in the course of engine start-up before the start of fuel injection. When the temperature correlation value is smaller than the threshold value, the second decompression operating processing is not executed.

A sensor mounting structure for an engine is provided. The sensor mounting structure offers a greater flexibility in mounting a sensor which detects an operation of an actuation member disposed at an inner wall spaced apart from an outer wall of a cylinder head of a valve gear. A sensor mounting structure for an engine includes a valve gear provided at a cylinder head and a sensor detecting an operation of the valve gear. The sensor is mounted on a sensor mounting hole formed at a head inner wall of the cylinder head covered with a cylinder head cover.

An engine oil passage structure for an engine contributing to downsizing the engine and achieving protection of an oil passage against external forces is provided. Provided is an oil passage structure for an engine installed in a small vehicle, the engine including an engine body formed of a crankcase and a cylinder block and a cylinder head stacked inclined vehicle frontward on the crankcase, the crankcase, the cylinder block, and the cylinder head being integrally fastened. The oil passage structure includes, near a bent part formed by a case front wall of the crankcase and a cylinder front wall of the cylinder block forming a valley part by an obtuse angle, a right-left direction oil passage extending in a right-left direction along the valley part.