Abstract: Lock pin (71) is disposed movably in axial direction in accommodation hole (70) formed at vane rotor (12). Top end portion of lock pin (71) is fitted into lock hole (23) provided at housing (11), then relative rotation position of vane rotor (12) is restrained at predetermined lock position. Vane rotor (12) is provided with small diameter portion (84) and large diameter portion (85) which are formed alternately in circumferential direction. Large diameter portion (85) extends in circumferential direction so as to cover lock hole (23). First vane (36A) protrudes from outer periphery of large diameter portion (85) to radially outer side. At least a part of lock pin (71) and at least a part of accommodation hole (70) overlap with large diameter portion (85), and are located at position that overlaps with area (86) formed by elongating first vane (36A) to radially inner side.

Abstract: Lock pin (71) is disposed movably in axial direction in accommodation hole (70) formed at vane rotor (12). Top end portion of lock pin (71) is fitted into lock hole (23) provided at housing (11), then relative rotation position of vane rotor (12) is restrained at predetermined lock position. Vane rotor (12) is provided with small diameter portion (84) and large diameter portion (85) which are formed alternately in circumferential direction. Large diameter portion (85) extends in circumferential direction so as to cover lock hole (23). First vane (36A) protrudes from outer periphery of large diameter portion (85) to radially outer side. At least a part of lock pin (71) and at least a part of accommodation hole (70) overlap with large diameter portion (85), and are located at position that overlaps with area (86) formed by elongating first vane (36A) to radially inner side.

Abstract: A lock determination device for variable valve timing mechanism includes means for detecting an operating position of a variable valve timing mechanism having a function of locking a valve timing of an internal combustion engine in an intermediate position between a most retarded position where the valve timing is most retarded and a most advanced position where the valve timing is most advanced in stopping operation of the internal combustion engine, means for starting a timer when the operating position of the variable valve timing mechanism enters an intermediate region, the intermediate region being a predetermined region including the intermediate position, means for determining whether or not the operating position of the variable valve timing mechanism is in a determination holding region wider on a retardation side than the intermediate region after the timer is started, means for incrementing a value of the timer if the operating position of the variable valve timing mechanism is in the determination

Abstract: A lock determination device for variable valve timing mechanism includes means for detecting an operating position of a variable valve timing mechanism having a function of locking a valve timing of an internal combustion engine in an intermediate position between a most retarded position where the valve timing is most retarded and a most advanced position where the valve timing is most advanced in stopping operation of the internal combustion engine, means for starting a timer when the operating position of the variable valve timing mechanism enters an intermediate region, the intermediate region being a predetermined region including the intermediate position, means for determining whether or not the operating position of the variable valve timing mechanism is in a determination holding region wider on a retardation side than the intermediate region after the timer is started, means for incrementing a value of the timer if the operating position of the variable valve timing mechanism is in the determination

Abstract: When an intermediate lock by an intermediate lock mechanism is released, one of two lock keys, which restricts a shift in a direction opposite to a direction that valve timing of an intake valve has been controlled by controlling the valve timing of the intake valve to a phase-advance side with respect to an intermediate lock position, is pulled out of an engaging recessed portion. Thereafter, the other of the two lock keys is pulled out of an engaging recessed portion by controlling the valve timing of the intake valve to a phase-retard side with respect to the intermediate lock position. Therefore, the intermediate lock by the intermediate lock mechanism can be released, while avoiding the lock keys from being pushed against the respective engaging recessed portions.

Abstract: Intermediate position feedback control is executed when valve timing of an intake valve is at an intermediate lock position, an intermediate lock is needed, and an engine revolution speed is greater than a first engine revolution speed R1. Forced lock control is executed when the valve timing of the intake valve is at the intermediate lock position, the intermediate lock is needed, the engine revolution speed is less than the first engine revolution speed R1, and the intermediate position feedback control is not being executed. As a result, even when the engine revolution speed increases in the presence of a demand that the valve timing needs to be in the intermediate lock position, it is possible to maintain the valve timing at the intermediate lock position.

Abstract: To achieve an intermediate lock state in a short period when an engine is stopped and improve the accuracy of confirmation of the intermediate lock state, an engine valve timing control apparatus includes a variable valve timing mechanism configured to vary engine valve timing, and an intermediate lock mechanism configured to restrict relative rotation positions of a first and a second rotor of the valve timing mechanism at an intermediate lock position for starting the engine. Upon detection of an engine stop request, the valve timing mechanism and the intermediate lock mechanism are driven and controlled for establishing an intermediate lock state. When a predetermined period from detection of the engine stop request has expired without detecting the intermediate lock state within the predetermined period, an engine stopping process is executed. Even after the engine stopping process has been executed, monitoring of the intermediate lock state is continued.

Abstract: Intermediate position feedback control is executed when valve timing of an intake valve is at an intermediate lock position, an intermediate lock is needed, and an engine revolution speed is greater than a first engine revolution speed R1. Forced lock control is executed when the valve timing of the intake valve is at the intermediate lock position, the intermediate lock is needed, the engine revolution speed is less than the first engine revolution speed R1, and the intermediate position feedback control is not being executed. As a result, even when the engine revolution speed increases in the presence of a demand that the valve timing needs to be in the intermediate lock position, it is possible to maintain the valve timing at the intermediate lock position.

Abstract: When an intermediate lock by an intermediate lock mechanism is released, one of two lock keys, which restricts a shift in a direction opposite to a direction that valve timing of an intake valve has been controlled by controlling the valve timing of the intake valve to a phase-advance side with respect to an intermediate lock position, is pulled out of an engaging recessed portion. Thereafter, the other of the two lock keys is pulled out of an engaging recessed portion by controlling the valve timing of the intake valve to a phase-retard side with respect to the intermediate lock position. Therefore, the intermediate lock by the intermediate lock mechanism can be released, while avoiding the lock keys from being pushed against the respective engaging recessed portions.

Abstract: To achieve an intermediate lock state in a short period when an engine is stopped and improve the accuracy of confirmation of the intermediate lock state, an engine valve timing control apparatus includes a variable valve timing mechanism configured to vary engine valve timing, and an intermediate lock mechanism configured to restrict relative rotation positions of a first and a second rotor of the valve timing mechanism at an intermediate lock position for starting the engine. Upon detection of an engine stop request, the valve timing mechanism and the intermediate lock mechanism are driven and controlled for establishing an intermediate lock state. When a predetermined period from detection of the engine stop request has expired without detecting the intermediate lock state within the predetermined period, an engine stopping process is executed. Even after the engine stopping process has been executed, monitoring of the intermediate lock state is continued.

Abstract: An electromagnetically-powered valve operating apparatus has a relatively-small-sized intake valve operating unit as compared to the exhaust valve operating unit. The height of each of the upper and lower coil springs included in the intake valve operating unit is reduced by lowering a spring bias of each of the upper and lower coil springs as compared with the corresponding springs in the exhaust valve operating unit. A coil outside diameter and a coil height of each of the upper and lower electromagnetic coils in the intake-valve operating unit are both reduced by reducing the number of turns of each of the upper and lower coils along with the magnitude of the electromagnetic force created by each of the coils as compared with the corresponding coils of the exhaust valve operating unit.

Abstract: The present invention mitigates restriction due to the fact that the opening period (angular working range) of the intake valve becomes smaller in the early closing Miller cycle operation, in which the intake valve closing timing occurs before the bottom dead center. The crankshaft center O1 is offset on one side from the cylinder central axis X. The top dead center and the bottom dead center of the piston occur when the three points, namely the crankshaft center O1, the crankpin center O2, and the piston pin center O3 are aligned in one line. At this time, the connecting rod and the crank arm are inclined relative to the axis X. The inclination angle &thgr;bdc at the bottom dead center is greater than the inclination angle &thgr;tdc at the top dead center. Therefore, as the crankshaft rotates in the direction of arrow &ohgr;, the intake process and the expansion process become greater than 180° CA, while the compression process and the exhaust process become smaller than 180° crank angle.

Abstract: An electromagnetically-powered valve operating apparatus of an internal combustion engine of an automotive vehicle, comprises a relatively-small-sized intake-valve side valve operating unit and a relatively-large-sized exhaust-valve side valve operating unit. The intake-valve side valve operating unit is relatively down-sized in comparison with the exhaust-valve side valve operating unit, so that a spring height of each of upper and lower coil springs included in the intake-valve side valve operating unit is set at a smaller value by setting a spring bias of each of the upper and lower coil springs at a lower value than each of upper and lower coil springs included in the exhaust-valve side valve operating unit.

Abstract: A mechanical valve lifter for an internal combustion engine comprises a head section having a recessed portion on an upper face thereof, a skirt section formed integral with the head section and adapted to be in sliding-contact with a lifter guiding bore in an engine cylinder head, a mechanical valve-clearance adjusting shim put in the recessed portion, an annular groove formed in an upper face of a bottom wall of the recessed portion of the lifter body, a first through-opening formed in the shim to communicate with the annular groove, and a second through-opening formed in the head section to communicate with the annular groove and to penetrate the head section. The annular groove and the second through-opening are formed in an essentially zero bending moment area midway between a central axis of the head section and a peripheral wall of the recessed portion.