Variable valve timing apparatus

A variable valve timing apparatus that advances or retards opening timing and closing timing of an exhaust valve of an internal combustion engine through use of an oil pressure, the variable valve timing apparatus comprising:

• a variable timing device that rotates a vane toward a retarding side through application of the oil pressure to the vane to retard the opening timing and closing timing of the exhaust valve;
• an oil pressure supply device that includes:
• a supply port that supplies the oil pressure to the variable timing device;
• a valve element that increases or decreases an opening degree of the supply port;
• and
• an electromagnetic solenoid that drives the valve element, wherein the opening degree of the supply port is increased or decreased by the valve element to adjust the supply of the oil pressure to the variable timing device when supply of an electric power to the electromagnetic solenoid is controlled;
• a phase sensing device that senses a value of a phase, which indicates a degree of retarding of the opening timing and closing timing;
• and
• a control device that computes a target value of the phase based on an operational state of the internal combustion engine and controls the supply of the electric power to the electromagnetic solenoid based on a result of a comparison between the sensed value of the phase, which is obtained from the phase sensing device, and the target value of the phase, wherein:
• the variable timing device includes a limiting portion that limits rotation of the vane toward the retarding side and thereby defines a limit of a variable range of the phase at a most retarded side;
• the control device sets:
• a permissible range of a difference between the sensed value of the phase and the target value of the phase;
• and
• a threshold value of the sensed value of the phase;
• the control device includes:
• a first determining unit that determines whether the difference exceeds the permissible range;
• and
• a second determining unit that determines whether the sensed value of the phase reaches the threshold value when the first determining unit determines that the difference exceeds the permissible range;
• the control device has at least two modes as control modes of the electric power supply to the electromagnetic solenoid, which are used when the first determining unit determines that the difference exceeds the permissible range;
• one of the at least two modes is a special mode that is used when the second determining unit determines that the sensed value of the phase reaches the threshold value;
• another one of the at least two modes is a normal mode that is used when the second determining unit determines that the sensed value of the phase does not reach the threshold value;
• and
• in the special mode, the control device controls the supply of the electric power to the electromagnetic solenoid in such a manner that the opening degree of the supply port is larger than the opening degree of the supply port in the normal mode.

A variable valve timing apparatus that advances or retards opening timing and closing timing of an intake valve of an internal combustion engine through use of an oil pressure, the variable valve timing apparatus comprising:

• a variable timing device including a housing and a rotor, the variable timing device being configured to rotate a vane toward an advancing side through application of the oil pressure to the vane to advance the opening timing and closing timing of the intake valve;
• an oil pressure supply device that includes:
• a supply port that supplies the oil pressure to the variable timing device;
• a valve element that increases or decreases an opening degree of the supply port;
• and
• an electromagnetic solenoid that drives the valve element, wherein the opening degree of the supply port is increased or decreased by the valve element to adjust the supply of the oil pressure to the variable timing device when supply of an electric power to the electromagnetic solenoid is controlled;
• a phase sensor configured to sense a value of a phase, which indicates a degree of advancing of the opening timing and closing timing;
• and
• a controller configured to compute a target value of the phase based on an operational state of the internal combustion engine and control the supply of the electric power to the electromagnetic solenoid based on a result of a comparison between the sensed value of the phase, which is obtained from the phase sensor, and the target value of the phase, wherein:
• a wall of the housing limits rotation of the vane toward the advancing side and thereby defines a limit of a variable range of the phase at a most advanced side;
• the controller is configured to set:
• a permissible range of a difference between the sensed value of the phase and the target value of the phase;
• and
• a threshold value of the sensed value of the phase;
• the controller is configured to:
• make a first determination that determines whether the difference exceeds the permissible range;
• and
• make a second determination that determines whether the sensed value of the phase reaches the threshold value when the first determination determines that the difference exceeds the permissible range;
• the controller has at least two modes as control modes of the electric power supply to the electromagnetic solenoid, which are used when the first determination determines that the difference exceeds the permissible range;
• one of the at least two modes is a special mode that is used when the second determination determines that the sensed value of the phase reaches the threshold value;
• another one of the at least two modes is a normal mode that is used when the second determination determines that the sensed value of the phase does not reach the threshold value;
• and
• in the special mode, the controller controls the supply of the electric power to the electromagnetic solenoid in such a manner that the opening degree of the supply port is larger than the opening degree of the supply port in the normal mode.

A variable valve timing apparatus that advances or retards opening timing and closing timing of an exhaust valve of an internal combustion engine through use of an oil pressure, the variable valve timing apparatus comprising:

• a variable timing device including a housing and a rotor, the variable timing device being configured to rotate a vane toward a retarding side through application of the oil pressure to the vane to retard the opening timing and closing timing of the exhaust valve;
• an oil pressure supply device that includes:
• a supply port that supplies the oil pressure to the variable timing device;
• a valve element that increases or decreases an opening degree of the supply port;
• and
• an electromagnetic solenoid that drives the valve element, wherein the opening degree of the supply port is increased or decreased by the valve element to adjust the supply of the oil pressure to the variable timing device when supply of an electric power to the electromagnetic solenoid is controlled;
• a phase sensor configured to sense a value of a phase, which indicates a degree of retarding of the opening timing and closing timing;
• and
• a controller configured to compute a target value of the phase based on an operational state of the internal combustion engine and control the supply of the electric power to the electromagnetic solenoid based on a result of a comparison between the sensed value of the phase, which is obtained from the phase sensor, and the target value of the phase, wherein:
• a wall of the housing limits rotation of the vane toward the retarding side and thereby defines a limit of a variable range of the phase at a most retarded side;
• the controller is configured to set:
• a permissible range of a difference between the sensed value of the phase and the target value of the phase;
• and
• a threshold value of the sensed value of the phase;
• the controller is configured to:
• make a first determination that determines whether the difference exceeds the permissible range;
• and
• make a second determination that determines whether the sensed value of the phase reaches the threshold value when the first determination determines that the difference exceeds the permissible range;
• the controller has at least two modes as control modes of the electric power supply to the electromagnetic solenoid, which are used when the first determination determines that the difference exceeds the permissible range;
• one of the at least two modes is a special mode that is used when the second determination determines that the sensed value of the phase reaches the threshold value;
• another one of the at least two modes is a normal mode that is used when the second determination determines that the sensed value of the phase does not reach the threshold value;
• and
• in the special mode, the controller controls the supply of the electric power to the electromagnetic solenoid in such a manner that the opening degree of the supply port is larger than the opening degree of the supply port in the normal mode.