A valve arrangement is provided for supplying air to a combustion chamber of an internal combustion engine, the valve arrangement including a first valve, the first valve including a first valve head, a first valve stem and an internal cavity, which is partly located in the first valve stem and open towards a lower surface of the first valve head, a valve guide arranged to surround a portion of the first valve stem such that the first valve stem is movable in the valve guide along a longitudinal direction between an upper, closed position of the valve, and a lower, open position, in which open position air may be supplied to the combustion chamber past the first valve head, the valve guide including an air passage allowing supply of additional air to the combustion chamber via the internal cavity in the first valve, when the first valve is in its closed position. The valve arrangement includes a guide leakage preventing means for preventing liquid from leaking from a region externally of the first valve stem to the valve guide air passage.

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.

A method for estimating wear of at least one component of an internal combustion engine includes receiving sensor information and fuel commands indicative of an amount of fuel supplied to at least one combustion chamber of the internal combustion engine and determining an incremental increase in an amount of wear of at least one component of the internal combustion engine based on at least the sensor information and the fuel commands. The method also includes determining an updated amount of wear based on the incremental increase in the amount of wear, and outputting a notification indicative of the updated amount of wear.

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 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 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 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 method for estimating wear of at least one component of an internal combustion engine includes receiving sensor information and fuel commands indicative of an amount of fuel supplied to at least one combustion chamber of the internal combustion engine and determining an incremental increase in an amount of wear of at least one component of the internal combustion engine based on at least the sensor information and the fuel commands. The method also includes determining an updated amount of wear based on the incremental increase in the amount of wear, and outputting a notification indicative of the updated amount of wear.

A valve seat insert of an engine has a valve seating surface including an outer curved segment forming a first wear crown for contacting the valve at an early wear state, an inner curved segment forming a second wear crown for contacting the valve at a later wear state, and a linear segment extending between the outer and the inner curved segments.