A valve train may include a camshaft having first and second slide guides, first and second cams mounted axially adjacent in torque-proof manners on the camshaft, and a cam follower adjustable between a first position, in which the cam follower is drivingly connected with the first cam, and a second position, in which the cam follower is drivingly connected with the second cam. The valve train may also include an adjustment arrangement having adjustable mechanical first and second engagement elements for axially adjusting the cam follower between first and second positions. Each engagement element may be adjustable between basic positions, in which no contact exists with a respective one of the slide guides, and switching positions, in which the respective engagement element cooperates with the slide guide. Each engagement element may have a spring that prestresses it into the switching position. The valve train may further include an arresting device and an actuator for each engagement element, wherein the arresting device, when in a locked position, holds the associated engagement element in the basic position, and the actuator releases the arresting device

A valve actuation system for an internal combustion engine is disclosed. The engine has a first set of cylinders having a first set of exhaust valves and a second set of cylinders having a second set of exhaust valves. The valve actuation system for the exhaust valves includes one or more first cams having a compression-release lobe and a main exhaust lobe adapted to transfer valve actuation motion to the first set of exhaust valves, and one or more second cams having an early exhaust valve opening (EEVO) lobe and a main exhaust lobe adapted to transfer valve actuation motion to the second set of exhaust valves. The valve actuation system may provide any combination of (i) main exhaust valve actuation with or without compression release actuation with (ii) main exhaust valve actuation with or without EEVO for the two sets of cylinders.

A valve switching apparatus includes a rocker arm coming into contact with a cam to open and close a valve along with a rotation of the cam, and an eccentric generation means provided to the rocker arm so as to allow an eccentric position to be changed by rotation thereof.

A method of providing diagnostic information for an electromagnetic latch assembly (122) includes providing a pulse to a circuit (200) that include one or more electromagnetic latch assemblies. The circuit (200) includes coils (199) of the electromagnetic latch assemblies. Each coil is inductively coupled with an armature (131) that is mechanically coupled to a latch pin (118). The circuit (200) is pulsed and a DC current in the circuit (200) that results from the pulse is measured over a first interval to determine a primary response. The current in the circuit (200) over a second interval is measured to determine a reference response. A second pulse may be used to generate the current for the reference response. The primary response and the reference response are compared to provide diagnostic information relating to position or movement of one or more of the latch pins (118).

A valve gear includes a camshaft, a first cam and a second cam that drive an intake valve or an exhaust valve, and a synchronous cam that rotates in synchronism with the first and second cams. The valve gear includes a rocker shaft, a rocker arm, and a cam follower swingably supported by the rocker shaft and that comes into contact with the synchronous cam. The valve gear includes a thruster that converts the swinging motion of the cam follower into a thrust and moves the rocker arm to a first side or a second side in the axial direction. The valve gear makes the camshaft compact, and also increases the reliability of operation at high rotations and reduces an operation sound at low rotations.

A variable valve mechanism includes an input arm that axially supports a roller pressed by a cam, via a roller pin, an output arm that drives a valve when swinging, a switch device that switches the variable valve mechanism between a coupled state where the both arms are coupled and an uncoupled state where the arms are uncoupled from each other, and a lost motion spring that biases the roller against the cam when in the uncoupled state. The lost motion spring includes an extended portion extending in an inter-arm clearance between the input arm and the output arm. An end of the roller pin projects from the input arm into the inter-arm clearance by such a length that the end is accommodated in the inter-arm clearance and that allows a spring retaining portion to be formed in the end. The spring retaining portion is formed in the end.

A camshaft for an internal combustion engine, with a drivable basic shaft and a cam piece which is mounted in the basic shaft, wherein the basic shaft passes through a passage in the cam piece, and the cam piece is mounted in the basic shaft in a rotationally fixed and axially displaceable manner. In the case of such a camshaft, it is provided that the basic shaft has a polygonal profile, and the passage in the cam piece has a complementary polygonal profile for receiving the basic shaft. The camshaft is preferably used in a motorcycle which has an internal combustion engine with two cylinders.

A sliding camshaft is provided which may include a base shaft, an over-molded trigger wheel, and a distal axially movable structure. The distal axially movable structure may further include a distal journal in addition to at least one standard journal and lobe packs. A control groove is defined in the distal axially movable structure. The over-molded trigger wheel is mounted on the distal axially movable structure. The over-molded trigger wheel is operatively configured to move between at least a first position and a second position together with the distal axially movable structure via engagement between the control groove and an actuator. The over-molded trigger wheel may be press fitted on distal axially movable structure and is adapted to accurately communicate with a sensor regardless of the position of the distal axially movable structure.

A novel latch seat for a switching rocker arm assembly used in variable valve actuation (VVA) systems for internal combustion engines. The seat is formed interactively in the assembled switching rocker arm using a novel fixture and press. The press interactively creates a curved dimple of the correct curvature, position and depth while measuring several lash dimensions. Since the latch seat is formed on the assembled rocker arm assembly, the latch seat depth is designed to account for the inaccuracies in the rocker arm assembly parts which create lash. Therefore all of the parts may be made with less precision since the latch seat is sized to compensate for the inaccuracies of all of the parts. The rocker arm assembly parts now may be manufactured to less stringent standards, but result in a rocker arm assembly with same accuracy of rocker arm assemblies manufactured to previous standards.

A rocker arm assembly constructed in accordance to one example of the present disclosure includes an outer rocker arm and an inner rocker arm. The outer rocker arm has a first roller configuration that rotates around a first axis. The inner rocker arm has a second roller configuration that rotates around a second axis. The inner rocker arm is configured to move between a latched and unlatched position relative to the outer rocker arm. One of the first and second axes is positioned for alignment over an engine valve. The other of the first and second axes is offset from the engine valve.