The invention relates to a control device for a multi-cylinder engine provided with an oil pump, a hydraulically operated valve characteristic control device which changes valve characteristics of at least one of an intake valve and an exhaust valve; and a hydraulically operated valve stop device which stops at least one of the intake valve and the exhaust valve when a reduced cylinder operation is performed. The control device for a multi-cylinder engine is provided with a valve control unit which operates the valve stop device after an operation of the valve characteristic control device is completed when the valve characteristic control device is operated at a time of request for the reduced cylinder operation.

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 valvetrain includes a rocker arm assembly having a rocker arm and an electromagnetic latch assembly. An electromagnet of the latch assembly is housed within a chamber formed by the rocker arm. Passageways suitable for oil cooling of the electromagnet are formed through and inside the rocker arm. In some embodiments, oil for cooling is supplied through a pivot. In some embodiments, oil for cooling is obtained from oil splash. Oil cooling may allow modes of operation such as of dynamic cylinder deactivation and dynamic variable valve actuation to be used without overheating the electromagnet.

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 switchable valve train assembly including a rocker shaft is provided. The rocker shaft includes a first chamber extending between a first axial end and a second axial end of the rocker shaft and a second chamber extending between the first axial end and the second axial end of the rocker shaft. A seepage orifice is defined between the first chamber and the second chamber and provides a fluid connection between the first chamber and the second chamber. The first chamber includes a first actuator port in fluid connection with a first intake port for a hydraulic lash adjuster. The second chamber includes a second actuator port in fluid connection with a second intake port for a locking assembly.

Provided is a V engine which uses common cylinder heads, and permits favorable arrangement of oil passages so as to accommodate various oil regulating features that are required to operate valve property varying mechanisms. Each end of each cylinder head is formed with a plurality of distribution oil passages opening out at an upper surface of the cylinder head for supplying oil pressure from a main gallery to a valve actuating mechanism. A pair of oil passage connecting members internally defining mutually different connecting oil passages are attached to the upper surfaces of the corresponding end parts of the respective cylinder heads.

A lost motion mechanism can comprise a castellation device, comprising a casing, an upper castellation, and a lower castellation. The casing can comprise a first linear slot and a second linear slot perpendicular to the first linear slot. Upper castellation can comprise an upper body, spaced upper teeth extending from the upper body, the spaced upper teeth forming spaced upper gaps therebetween, and an actuation peg extending from the upper body into the first linear slot. Lower castellation can comprise a lower body, spaced lower teeth extending from the lower body, the spaced lower teeth forming spaced lower gaps therebetween, and an anti-rotation peg extending from the lower body into the second linear slot. An actuator can be configured with the lost motion mechanism so that a movable arm comprises a forked end configured to move on the actuation peg as the movable arm swivels.

The variable valve actuating device (20) comprises a switch pin (53) slidably received in the valve lifter (24) so as to selectively abut the end surface of the valve stem as the valve lifter is actuated by the cam. The device further comprises a first spring retainer (36) attached to an intermediate part of the valve stem (32) to engage a first valve spring (35), and a second spring retainer (44) slidably engaged by an end part of the valve stem to engage a second valve spring (43). The valve stem is provided with a stem end (39) which is enlarged with respect to a part of the valve stem slidably engaging the second spring retainer so as to define a shoulder surface (40a) that engages the second spring retainer against a spring force of the second valve spring.

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.