Abstract: A variable valve timing apparatus for an internal combustion engine, including: an actuator that activates a variable valve timing mechanism; a detection unit that detects a driving position of the actuator; a control unit that drive-controls the actuator, and when a predetermined execution condition is established, executes one of a first initialization process and a second initialization process that match the driving position of the actuator detected by the detection unit with an actual driving position of the actuator; and an abnormality determination unit that determines whether or not an abnormality is present in the driving position detected by the detection unit and stores an abnormality history after determining that an abnormality is present. The control unit executes the first initialization process when the abnormality history is stored and the second initialization process when the abnormality history is not stored.

Abstract: A drive circuit (203) of an actuator (2) calculates an actual working angle from an actual operation quantity with reference to a reference table used to calculate a target operation quantity, and transmits the actual working angle and the actual operation quantity to a command unit (4). The command unit (4) determines whether or not the received values of the actual working angle and the operation quantity correspond to the valve working angle and the operation quantity of the reference table stored in the command unit (4), to detect a discrepancy between the operation modes of the actuator (2) and the command unit (4).

Abstract: A cam element portions is configured such that respective maximum lift portions (lift ending points) of both-side end-face cams thereof are provided at respective phases which are different from each other in a rotational direction and that a maximum value of a length, in an axial direction, between respective cam faces of the both-side end-face cams which are provided at the same phase is set to be a distance, in the axial direction, between a first operational member and a second operational member or smaller. Accordingly, in a valve gear of an engine in which cams operative to control opening/closing of a valve are switchable, it can be properly prevented that a camshaft locks and stop rotating because of an operational malfunction of an operational member or the like.

Abstract: A cam element portion comprises a slant portion (reverse-rotation return slope portion), which is positioned on a rotary-delay side from a maximum-lift portion (lift ending point) of an end-face cam and slants inward toward the rotary-delay side from an outer peripheral face of the end-face cam. Accordingly, in a valve gear of an engine in which cams operative to control opening/closing of a valve are switchable, it can be properly prevented that the cam element portion is switched unexpectedly and improperly or an operational member breaks down which are possibly caused by an engine's reverse rotation.

Abstract: A cam element portion comprises a slant portion (reverse-rotation return slope portion), which is positioned on a rotary-delay side from a maximum-lift portion (lift ending point) of an end-face cam and slants inward toward the rotary-delay side from an outer peripheral face of the end-face cam. Accordingly, in a valve gear of an engine in which cams operative to control opening/closing of a valve are switchable, it can be properly prevented that the cam element portion is switched unexpectedly and improperly or an operational member breaks down which are possibly caused by an engine's reverse rotation.

Abstract: A cam element portions is configured such that respective maximum lift portions (lift ending points) of both-side end-face cams thereof are provided at respective phases which are different from each other in a rotational direction and that a maximum value of a length, in an axial direction, between respective cam faces of the both-side end-face cams which are provided at the same phase is set to be a distance, in the axial direction, between a first operational member and a second operational member or smaller. Accordingly, in a valve gear of an engine in which cams operative to control opening/closing of a valve are switchable, it can be properly prevented that a camshaft locks and stop rotating because of an operational malfunction of an operational member or the like.

Abstract: An electronic control unit (100) detects the position of an output shaft (221) by counting a position count value based on pulse signals generated from position sensors (S4, S5) in accordance with rotation of a motor (210). The electronic control unit (100) determines that the motor (210) is in a predetermined rotational phase, based on the pulse signals generated from the position sensors (S4, S5). The electronic control unit (100) determines the number of revolutions that have been made by the motor (210) when the determination is made, based on the magnitude of current applied to the motor (210) when the determination is made, and updates the position count value based on a reference count value stored in association with the predetermined rotational phase.

Abstract: An electronic control unit that controls a variable operation angle mechanism that varies an operation angle of an intake valve reduces an operation angle of the intake valve to a normal startup operation angle after first maintaining the operation angle of the intake valve at a high temperature restart operation angle that is larger than the normal startup operation angle for a predetermined period of time after an engine is stopped.

Abstract: A variable valve timing apparatus for an internal combustion engine, including: an actuator (15) that activates a variable valve timing mechanism; a detection unit (35) that detects a driving position of the actuator; a control unit (21) that drive-controls the actuator, and when a predetermined execution condition is established, executes one of a first initialization process and a second initialization process that match the driving position of the actuator detected by the detection unit with an actual driving position of the actuator; and an abnormality determination unit (21) that determines whether or not an abnormality is present in the driving position detected by the detection unit and stores an abnormality history after determining that an abnormality is present. The control unit executes the first initialization process when the abnormality history is stored and the second initialization process when the abnormality history is not stored.

Abstract: An electronic control unit (100) detects the position of an output shaft (221) by counting a position count value based on pulse signals generated from position sensors (S4, S5) in accordance with rotation of a motor (210). The electronic control unit (100) determines that the motor (210) is in a predetermined rotational phase, based on the pulse signals generated from the position sensors (S4, S5). The electronic control unit (100) determines the number of revolutions that have been made by the motor (210) when the determination is made, based on the magnitude of current applied to the motor (210) when the determination is made, and updates the position count value based on a reference count value stored in association with the predetermined rotational phase.

Abstract: In a control apparatus and a control method for a variable mechanism, when a predetermined condition is fulfilled, a movable member (3) is driven until an engagement portion (31) contacts one restriction member (22), and the absolute position of the movable member (3) when it is determined that displacement of the movable member (3) is stopped is learned, as a reference position. When supply of electric power is stopped, the absolute position of the movable member (3) is learned as an initial reference position. When electric power is supplied, the movable member (3) is driven from the initial reference position until the engagement portion (31) contacts the one restriction member (22), and a one-side displacement amount is calculated. If the one-side displacement amount is smaller than a one-side distance, it is determined that a foreign substance is caught in an area on a side of a site corresponding to the one restriction member (22) in a movable range.

Abstract: An electronic control unit that controls a variable operation angle mechanism that varies an operation angle of an intake valve reduces an operation angle of the intake valve to a normal startup operation angle after first maintaining the operation angle of the intake valve at a high temperature restart operation angle that is larger than the normal startup operation angle for a predetermined period of time after an engine is stopped.

Abstract: A drive circuit (203) of an actuator (2) calculates an actual working angle from an actual operation quantity with reference to a reference table used to calculate a target operation quantity, and transmits the actual working angle and the actual operation quantity to a command unit (4). The command unit (4) determines whether or not the received values of the actual working angle and the operation quantity correspond to the valve working angle and the operation quantity of the reference table stored in the command unit (4), to detect a discrepancy between the operation modes of the actuator (2) and the command unit (4).