A valvetrain for an internal combustion engine of the type that has a combustion chamber, a moveable valve having a seat formed in the combustion chamber, and a camshaft includes a rocker arm assembly, a pivot providing a fulcrum for a rocker arm of the rocker arm assembly, and a latch assembly. An electrical device mounted to the rocker arm assembly receives power or communicates through a circuit that includes an electrical connection formed by abutment between surfaces of two distinct parts. The rocker arm assembly is operative to move one of the two abutting surfaces relative to the other in response to actuation of the cam follower. Forming an electrical connection through abutting surfaces that are free to undergo relative motion may reduce or eliminate the need to run wires to a mobile portion of the rocker arm assembly.

A switching rocker arm for engaging a cam includes a first arm having a first end and a second end, and a first and a second side arm; a second arm disposed between the first and second side arms, having a first end and a second end, where the second arm is an inner arm. The second arm is pivotably secured adjacent its first end to the first arm adjacent the first end of the first arm. The rocker arm includes an over-travel limiter that limits pivoting motion of the first arm relative to the second arm, where the over-travel limiter is pivotally coupled to the outer arm and interacts with the inner arm.

A rocker arm includes an outer arm having a first side and a second side, an inner arm positioned between the first side and the second side of the outer arm, a pivot axle pivotally coupling the inner arm and the outer arm at a first end of each of the inner arm and the outer arm, and a latch having a first position and a second position. The latch in the first position pivotally fixes the inner arm and the outer arm at a second end of each of the inner arm and the outer arm, and in the second position allows the inner arm and the outer arm to pivot independently. The latch is responsive to hydraulic pressure in a hydraulic fluid passage to selectively move to other of the first position and the second position. A lost motion spring is coupled to the inner arm.

A system includes a rocker arm assembly for operative engagement with a first and second cam. The assembly includes a first arm for operatively engaging the first cam for a first desired lift profile, a second arm for operatively engaging the second cam for a second desired lift profile, where the second arm includes a latch to engage the second arm with the first arm. The latch is responsive to supplied oil pressure and release oil pressure to switch between lift profiles. The system includes the latch coupled to the supplied or released oil pressure to engage the arms before the first and second arms are engaged with the base circle portion of each of the respective first and second cams.

A system includes a rocker arm assembly for operative engagement with a first and second cam. The assembly includes a first arm for operatively engaging the first cam for a first desired lift profile, a second arm for operatively engaging the second cam for a second desired lift profile, where the second arm includes a latch to engage the second arm with the first arm. The latch is responsive to supplied oil pressure and release oil pressure to switch between lift profiles. The system includes the latch coupled to the supplied or released oil pressure to engage the arms before the first and second arms are engaged with the base circle portion of each of the respective first and second cams.

An internal combustion engine includes a cylinder head and a valvetrain including a poppet valve, a cam shaft on which is mounted a cam, and a rocker arm assembly. The rocker arm assembly includes a rocker arm and a cam follower configured to engage the cam as the cam shaft rotates. The rocker arm assembly is operative to transmit force from the cam to actuate the valve and includes an electrical device mounted to the rocker arm. A first electrical circuit includes the electrical device and a first conductor mounted to the rocker arm and a second electrical circuit includes a second conductor mounted off the rocker arm. The first and second conductors are inductively coupled to an extent that enables effective power transfer or communication between them. Inductive power transfer avoids the use of wires that could become caught, clipped, or fatigued and consequently short out.

A system includes a rocker arm assembly for operative engagement with a first and second cam. The assembly includes a first arm for operatively engaging the first cam for a first desired lift profile, a second arm for operatively engaging the second cam for a second desired lift profile, where the second arm includes a latch to engage the second arm with the first arm. The latch is responsive to supplied oil pressure and release oil pressure to switch between lift profiles. The system includes the latch coupled to the supplied or released oil pressure to engage the arms before the first and second arms are engaged with the base circle portion of each of the respective first and second cams.

In one embodiment, a method is provided. The method includes receiving a signal representative of an engine vibration transmitted via a knock sensor, wherein the knock sensor is disposed in an engine. The method additionally includes deriving a valve wear measurement during operation of the engine based on the signal. The method further includes communicating the valve wear measure.

A valvetrain for an internal combustion engine of the type that has a combustion chamber, a moveable valve having a seat formed in the combustion chamber, and a camshaft includes a rocker arm assembly, a pivot providing a fulcrum for a rocker arm of the rocker arm assembly, and a latch assembly. An electrical device mounted to the rocker arm assembly receives power or communicates through a circuit that includes an electrical connection formed by abutment between surfaces of two distinct parts. The rocker arm assembly is operative to move one of the two abutting surfaces relative to the other in response to actuation of the cam follower. Forming an electrical connection through abutting surfaces that are free to undergo relative motion may reduce or eliminate the need to run wires to a mobile portion of the rocker arm assembly.

A valvetrain for an internal combustion engine of the type that has a combustion chamber, a moveable valve having a seat formed in the combustion chamber, and a camshaft includes a rocker arm assembly, a pivot providing a fulcrum for a rocker arm of the rocker arm assembly, and a latch assembly. An electrical device mounted to the rocker arm assembly receives power or communicates through a circuit that includes an electrical connection formed by abutment between surfaces of two distinct parts. The rocker arm assembly is operative to move one of the two abutting surfaces relative to the other in response to actuation of the cam follower. Forming an electrical connection through abutting surfaces that are free to undergo relative motion may reduce or eliminate the need to run wires to a mobile portion of the rocker arm assembly.