Variable valve timing apparatus

Patent metadata

Field	Value
Publication number	US-10060305-B2
Application number	US-201615334583-A
Country	US
Kind code	B2
Filing date	Oct 26, 2016
Priority date	Oct 29, 2015
Publication date	Aug 28, 2018
Grant date	Aug 28, 2018

Abstract

A control device has two modes as control modes of an electric power supply to an electromagnetic solenoid, which are used when a first determining unit determines that a difference between a sensed value of a phase and a target value of the phase exceeds a permissible range. One of the modes is a special mode that is used when a second determining unit determines that the sensed value of the phase reaches a threshold value. Another one of the 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. In the special mode, the control device controls supply of the electric power to the electromagnetic solenoid in such a manner that an opening degree of an advancing port is larger than the opening degree of the advancing port in the normal mode.

First claim

What is claimed is:

1. 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 that rotates 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 sensing device that senses a value of a phase, which indicates a degree of advancing 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 advancing side and thereby defines a limit of a variable range of the phase at a most advanced 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.

2. The variable valve timing apparatus according to claim 1 , wherein the threshold value is a boundary value of the variable range of the phase on the most advanced side.

3. The variable valve timing apparatus according to claim 1 , wherein:
an extent of oscillation of the phase relative to the target value of the phase on the advancing side is defined as an amplitude; and
the threshold value is set between a boundary value of the variable range of the phase, which is on the most advanced side, and an amplitude value, which is displaced from the boundary value on a retarding side by the amplitude.

4. The variable valve timing apparatus according to claim 1 , wherein:
the control device controls the supply of the electric power to the electromagnetic solenoid by outputting a command value for an amount of electric power supplied to the electromagnetic solenoid;
a waveform of a temporal change in the command value for the amount of electric power in the special mode is a rectangular waveform; and
a waveform of a temporal change in the command value for the amount of electric power in the normal mode is a triangular waveform.

5. 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.

6. The variable valve timing apparatus according to claim 5 , wherein the threshold value is a boundary value of the variable range of the phase on the most retarded side.

7. The variable valve timing apparatus according to claim 5 , wherein:
an extent of oscillation of the phase relative to the target value of the phase on the retarding side is defined as an amplitude; and
the threshold value is set between a boundary value of the variable range of the phase, which is on the most retarded side, and an amplitude value, which is displaced from the boundary value on an advancing side by the amplitude.

Assignees

• Denso Corp
• Nippon Soken
• Toyota Motor Co Ltd

Inventors

• Toda Shota
• Oe Shuhei
• Fujiyoshi Toshiki
• Fujimura Haruhito
• Yokoyama Yu

Classifications

• F01L2201/00

  Electronic control systems; Apparatus or methods therefor · CPC title

• F01L2001/3443

  Solenoid driven oil control valves · CPC title

• F01L2001/34436

  Features or method for avoiding malfunction due to foreign matters in oil · CPC title

• F01L1/3442 Primary

  using hydraulic chambers with variable volume to transmit the rotating force · CPC title

• F01L2001/34443

  Cleaning control of oil control valves · CPC title