An engine including a motorized throttle valve that can implement mutually neighboring disposition of a throttle body and a cylinder head and can implement a good opening and closing responsibility thereof. A swelling portion is formed on a side wall of a valve chamber in such a manner so as to bite between those of throttle bodies which neighbor with each other in order to accept a protrusion of part of a valve system in a radial direction of first and second camshafts. An electric motor is disposed at one side of the group of the throttle bodies. A speed reduction mechanism, for transmitting output power of the electric motor to a valve shaft, is disposed between those throttle bodies, which neighbor with each other at a different location in the group of the throttle bodies, in a neighboring relationship with the valve chamber.

The present disclosure provides systems and methods to compensate for backlash within a cam phasing system. For example, compensating for backlash by commanding a predetermined amount of additional actuator movement to account for backlash within a cam phaser. According to some aspects, a spring is provided within a cam phaser to unidirectionally take up the backlash within the cam phasing system.

Methods and systems are provided for a phase control apparatus in a variable cam timing (VCT) system of an engine, the phase control apparatus having a locked configuration where a locking pin coupled to a first vane of the vane rotor is engaged with a locking pin recess in a cover plate of the phase control apparatus. In one example, the phase control apparatus includes a rubber or plastic isolator pad positioned in a recess in a wall adjacent to the first vane such that when the vane rotor is rotated to the locked configuration, the first vane contacts the isolator pad before it can strike the housing. The isolator pad serves to maintain the gap between the first vane and the housing, and also reduces the likelihood of other vanes of the vane rotor from striking the housing.

For example, two intake valves for each cylinder each are driven by a selected one of cams via a corresponding rocker arm. Each rocker arm includes a support portion and a pressing portion (distal end portion). The support portion is rockably supported by a cylinder head. The pressing portion is configured to press a stem of the corresponding intake valve. The support portion of one of the rocker arms deviates to one side in an axis X direction (cam axial direction) with respect to the distal end portion. The support portion of the other one of the rocker arms deviates to the other side in the axis X direction with respect to the distal end portion.

The present disclosure provides systems and methods to compensate for backlash within a cam phasing system. For example, compensating for backlash by commanding a predetermined amount of additional actuator movement to account for backlash within a cam phaser. According to some aspects, a spring is provided within a cam phaser to unidirectionally take up the backlash within the cam phasing system.

Methods and systems are provided for a phase control apparatus in a variable cam timing (VCT) system of an engine, the phase control apparatus having a locked configuration where a locking pin coupled to a first vane of the vane rotor is engaged with a locking pin recess in a cover plate of the phase control apparatus. In one example, the phase control apparatus includes a rubber or plastic isolator pad positioned in a recess in a wall adjacent to the first vane such that when the vane rotor is rotated to the locked configuration, the first vane contacts the isolator pad before it can strike the housing. The isolator pad serves to maintain the gap between the first vane and the housing, and also reduces the likelihood of other vanes of the vane rotor from striking the housing.

A rocker arm includes a pivot portion that is journaled by a rocker arm shaft, a contact portion that projects from the pivot portion to a side of a valve cam, and a pressing portion that projects from the pivot portion to a side of a valve. While including a slipper projecting from the pivot portion in outer side in an axial direction to a side of a camshaft, an overhead valve actuation mechanism for the engine includes a stopper portion with which the slipper comes in contact when the rocker arm swings and reaches a predetermined position at a position opposing the slipper.

For example, two intake valves for each cylinder each are driven by a selected one of cams via a corresponding rocker arm. Each rocker arm includes a support portion and a pressing portion (distal end portion). The support portion is rockably supported by a cylinder head. The pressing portion is configured to press a stem of the corresponding intake valve. The support portion of one of the rocker arms deviates to one side in an axis X direction (cam axial direction) with respect to the distal end portion. The support portion of the other one of the rocker arms deviates to the other side in the axis X direction with respect to the distal end portion.

A rocker arm includes a pivot portion that is journaled by a rocker arm shaft, a contact portion that projects from the pivot portion to a side of a valve cam, and a pressing portion that projects from the pivot portion to a side of a valve. While including a slipper projecting from the pivot portion in outer side in an axial direction to a side of a camshaft, an overhead valve actuation mechanism for the engine includes a stopper portion with which the slipper comes in contact when the rocker arm swings and reaches a predetermined position at a position opposing the slipper.