A valve opening/closing timing control device includes: a driving side rotator synchronously rotating with a crankshaft of an internal combustion engine; a driven side rotator coaxially disposed with a rotation axis of the driving side rotator and integrally rotating with a valve opening/closing camshaft; advance and retard chambers formed between the driving side and driven side rotators; a lock mechanism including a lock member capable of engaging with a recessed portion on one of the driving side and driven side rotators and provided in the other of the driving side and driven side rotators; and a connecting bolt coaxially disposed with the rotation axis and connecting the driven side rotator to the camshaft. The connecting bolt includes an internal space, and an advance port, a retard port and a lock port are formed as through-holes, a valve unit accommodates a spool, and the spool includes an internal flow path.

A controller for an internal combustion engine includes: a failure determination section which determines a failure state in a case where a relative rotation phase of an intake side valve opening and closing timing control mechanism does not change when controlling the mechanism after starting the driving of a starter motor and trying to change the relative rotation phase of the mechanism in a start control for starting an internal combustion engine. When the section determines a failure, the controller performs at least one of an intake air amount increase control in which an opening degree of a throttle valve is increased, an ignition timing advance angle control in which injection of fuel is performed at a timing earlier than a set timing and ignition is performed, and a multi-injection control in which the fuel is injected immediately before the ignition in addition to the fuel injection in an intake stroke.

A method of operating a cam shaft phaser including a stator including a radially inwardly extending protrusion, a rotor including a radially outwardly extending protrusion and a slot in the radially outwardly extending protrusion, a cover non-rotatably connected to the stator, a chamber circumferentially bounded by the radially inwardly extending protrusion and the radially outwardly extending protrusion, a pin disposed in the slot, and a first channel connecting the chamber with the slot. The method comprises: blocking, with the locking pin, rotation of the rotor with respect to the stator; applying pulse width modulation voltage to a control valve as a non-rectangular wave form; flowing fluid from the control valve to the chamber; flowing the fluid through the first channel to the slot; axially displacing the locking pin with the fluid; disengaging the locking pin from the cover; and rotating the rotor with respect to the stator.

An engine includes a variable valve timing (VVT) mechanism that changes an opening timing or a closing timing of at least one of an intake valve or an exhaust valve in accordance with an operating region of the engine, and an oil jet that injects oil in a piston direction under a pressure of a first predetermined oil pressure or more. The control device of the engine controls supply of an oil pressure to the VVT mechanism in such a manner that an upper limit of an oil pressure used by the VVT mechanism is set to be lower than a first predetermined oil pressure and an operating speed of the VVT mechanism is high in a direction in which an overlap amount between open periods between an intake valve and an exhaust valve increases and is low in a direction in which the overlap amount decreases.

A valve opening/closing timing control device includes: a driving side rotator synchronously rotating with a crankshaft of an internal combustion engine; a driven side rotator coaxially disposed with a rotation axis of the driving side rotator and integrally rotating with a valve opening/closing camshaft; advance and retard chambers formed between the driving side and driven side rotators; a lock mechanism including a lock member capable of engaging with a recessed portion formed on one of the driving side and driven side rotators, and provided in the other of the driving side and driven side rotators; and a connecting bolt coaxially disposed with the rotation axis and connecting the driven side rotator to the camshaft, in which the connecting bolt includes an internal space, a valve unit accommodates a spool, and the spool includes an internal flow path, and, in the spool, a lock holding check valve is disposed.

In a valve timing control system, a control command unit includes: a first stage setting block and a next stage setting block. The first stage setting block sets a retard holding command value as a control command value to introduce hydraulic fluid to each retard operation chamber under a state where a rotation phase is locked, to start applying an operation pressure more than or equal to an unlock pressure to a lock component. The next stage setting block sets an advance holding command value as a control command value to introduce hydraulic fluid to each advance operation chamber, after setting the retard holding command value, to maintain the applying of the operation pressure more than or equal to the unlock pressure to the lock component.

A phasing system for an internal combustion engine having a concentric camshaft includes an annular stator rotatable by the crankshaft and having inner and outer circumferences, and two groups of arcuate cavities. The first group interrupts the inner circumference. A first phaser having an output member as a hub is mounted within the stator in contact with the inner circumference and supported directly on the camshaft tube as a concentric stator bearing. The first phaser has vanes connected to the output member and extending radially into the first group to divide cavities into opposed working chambers. A second phaser comprises first and second end plates at opposite stator sides and fastened to one another to axially seal the cavities therein and, as second output member of the second phaser, connect to vanes extending axially through the second group of cavities to divide the cavities into opposed working chambers.

A variable valve timing control device includes a phase detecting portion; a phase control portion driving an electromagnetic solenoid while obtaining a detection signal detected by the phase detecting portion to set a spool to one of a phase control region and a lock region; and a boundary memory portion memorizing a boundary electric current value for referring a boundary between the phase control region and the lock region when the phase control portion operates a phase control; and a characteristic calculation portion obtaining the boundary electric current value by calculation, the boundary electric current value supporting the boundary between the phase control region and the lock region based on solenoid characteristic information of the electromagnetic solenoid and valve characteristic information of an electromagnetic control valve, the characteristic calculation portion memorizing the boundary electric current value to the boundary memory portion.

A variable valve timing control device includes a valve unit including a spool having a plurality of land portions at an outer circumference of the spool, and being formed with a drain flow path inside the spool. The valve unit allows a second pump port and a lock port to communicate with each other in a case where the spool is set at an unlock position where a lock state of a lock mechanism is released, and the valve unit closes the second pump port with the land portion of the spool and allows the lock port to communicate with the drain flow path in a case where the spool is set at a lock position where the lock mechanism is allowed to be shifted in the lock state.

The number of advance chambers is larger than the number of retard chambers in an intake variable valve timing (VVT), whereas the number of retard chambers is larger than the number of advance chambers in an exhaust VVT. Accordingly, with limitation of an oil pressure that can be used by the VVTs, a pumping loss in a transition period in which a valve overlap amount is changed by advancing or retarding a valve timing can be reduced.