This application is based on Japanese Patent Application No. 2011-147821 filed on Jul. 3, 2011, the disclosure of which is incorporated herein by reference in its entirety.
The present disclosure relates to a valve characteristics control apparatus.
JP-A-2004-183612 (U.S. Pat. No. 7,047,922) describes a valve characteristics control apparatus that controls a valve timing and a valve working angle as valve characteristics of a valve of an internal combustion engine.
In the valve characteristics control apparatus, a motor is engaged with a camshaft through a gear train. The motor controls the valve timing and the valve working angle by varying the rotating speed of the camshaft from a basic velocity that is set as a half of a rotating speed of a crankshaft.
The valve characteristics control apparatus is required to electrically accurately control the rotating speed of the motor, which determines the rotating speed of the camshaft, while the rotating speed of the crankshaft of the combustion engine is varied every moment. However, an acting direction of a variation torque applied to the camshaft from a spring reaction force of the valve is alternately changed in accordance with the rotation of the crankshaft. Therefore, it is difficult to accurately control the rotating speed of the motor, while the variation torque is absorbed by a torque generated by the motor, so that the accuracy of controlling the valve characteristics may become low.
According to a first example of the present disclosure, a valve characteristics control apparatus that controls valve characteristics of a valve opened and closed by a rotation of a camshaft in accordance with a rotation of a crankshaft in an internal combustion engine includes a housing rotating with the crankshaft; a first vane rotor; a control valve part; a second vane rotor; a check valve part; and a switch valve part. The first vane rotor has a first vane rotatably received in the housing, and a first advance chamber and a first retard chamber are defined by partitioning a space between the housing and the first vane in a rotation direction. The first vane rotor has a relative rotation with respect to the housing in an advance direction when working fluid is introduced into the first advance chamber and when working fluid is discharged from the first retard chamber. The first vane rotor has a relative rotation with respect to the housing in a retard direction when working fluid is discharged from the first advance chamber and when working fluid is introduced into the first retard chamber. The control valve part switches a flowing direction of working fluid between the first advance chamber and the first retard chamber in a timing adjustment mode adjusting valve timing as the valve characteristics, and restricts working fluid from flowing between the first advance chamber and the first retard chamber in a working angle adjustment mode adjusting a valve working angle as the valve characteristics. The second vane rotor has a second vane rotating with the camshaft in a state that the second vane is projected into the first vane in the housing, and a second advance chamber and a second retard chamber are defined by partitioning a space between the first vane and the second vane in the rotation direction. The second vane rotor has a relative rotation with respect to the first vane rotor in the advance direction when working fluid is introduced into the second advance chamber and when working fluid is discharged from the second retard chamber. The second vane rotor has a relative rotation with respect to the first vane rotor in the retard direction when working fluid is discharged from the second advance chamber and when working fluid is introduced into the second retard chamber. The check valve part has a check passage connecting the second advance chamber and the second retard chamber with each other. The check valve part allows working fluid to flow from the second retard chamber through the check passage to the second advance chamber, and restricts working fluid from flowing from the second advance chamber through the check passage to the second retard chamber. The switch valve part has a switch passage connecting the second advance chamber and the second retard chamber with each other. The switch valve part allows a communication between the second advance chamber and the second retard chamber through the switch passage in the working angle adjustment mode, and prohibits the communication between the second advance chamber and the second retard chamber through the switch passage in the timing adjustment mode.
According to a second example of the present disclosure, a valve characteristics control apparatus that controls valve characteristics of a valve opened and closed by a rotation of a camshaft in accordance with a rotation of a crankshaft in an internal combustion engine includes a housing rotating with the crankshaft; a first vane rotor; a control valve part; a second vane rotor; a check valve part; and a switch valve part. The first vane rotor has a first vane rotatably received in the housing, and a first advance chamber and a first retard chamber are defined by partitioning a space between the housing and the first vane in a rotation direction. The first vane rotor has a relative rotation with respect to the housing in an advance direction when working fluid is introduced into the first advance chamber and when working fluid is discharged from the first retard chamber. The first vane rotor has a relative rotation with respect to the housing in a retard direction when working fluid is discharged from the first advance chamber and when working fluid is introduced into the first retard chamber. The control valve part switches a flowing direction of working fluid between the first advance chamber and the first retard chamber in a timing adjustment mode adjusting valve timing as the valve characteristics, and restricts working fluid from flowing between the first advance chamber and the first retard chamber in a working angle adjustment mode adjusting a valve working angle as the valve characteristics. The second vane rotor has a second vane rotating with the camshaft in a state that the second vane is projected into the first vane in the housing, and a second advance chamber and a second retard chamber are defined by partitioning a space between the first vane and the second vane in the rotation direction. The second vane rotor has a relative rotation with respect to the first vane rotor in the advance direction when working fluid is introduced into the second advance chamber and when working fluid is discharged from the second retard chamber. The second vane rotor has a relative rotation with respect to the first vane rotor in the retard direction when working fluid is discharged from the second advance chamber and when working fluid is introduced into the second retard chamber. The check valve part has a check passage connecting the second advance chamber and the second retard chamber with each other. The check valve part allows working fluid to flow from the second advance chamber through the check passage to the second retard chamber, and restricts working fluid from flowing from the second retard chamber through the check passage to the second advance chamber. The switch valve part has a switch passage connecting the second advance chamber and the second retard chamber with each other. The switch valve part allows a communication between the second advance chamber and the second retard chamber through the switch passage in the working angle adjustment mode, and prohibits the communication between the second advance chamber and the second retard chamber through the switch passage in the timing adjustment mode.
The above and other objects, features and advantages of the present disclosure will become more apparent from the following detailed description made with reference to the accompanying drawings. In the drawings:
Embodiments of the present invention will be described hereafter referring to drawings. In the embodiments, a part that corresponds to a matter described in a preceding embodiment may be assigned with the same reference numeral, and redundant explanation for the part may be omitted. When only a part of a configuration is described in an embodiment, another preceding embodiment may be applied to the other parts of the configuration. The parts may be combined even if it is not explicitly described that the parts can be combined. The embodiments may be partially combined even if it is not explicitly described that the embodiments can be combined, provided there is no harm in the combination.
The drive system 3 will be described with reference to
The metal housing 10 is constructed by joining a pair of accommodation plates 13, 14 to axial ends of a main part 12, respectively, and has a hollow shape as a whole. The main part 12 has an accommodation wall 120 and plural shoes 122.
As shown in
Each of the convex shoes 122 is projected inward in the radial direction from the wall 120, and the shoes 122 are located with regular intervals in the rotation direction. A first accommodation chamber 16 is defined between the shoes 122 located adjacent with each other in the rotation direction.
The first vane rotor 20 is accommodated between the accommodation plates 13 and 14 in the axis direction in the housing 10, and is slidably fitted with each of the plates 13 and 14. The first vane rotor 20 has plural rotation walls 200 and plural first vanes 202.
The rotation wall 200 partially has a cylindrical shape, and is located on the inner side of the corresponding shoe 122 in the radial direction. The rotation wall 200 is slidably fitted to a projection-side end portion of the corresponding shoe 122. The fitting structure allows the first vane rotor 20 to rotate in the counterclockwise direction and to have relative rotation with respect to the housing 10.
The concave first vane 202 defines a second chamber 26 opening to the inner side in the radial direction by recessing outward in the radial direction from a position between the rotation walls 200 in the rotation direction. The first vane 202 is accommodated in the corresponding first accommodation chamber 16 so as to partition the chamber 16 in the rotation direction, so that the first vane 202 defines a first advance chamber 16a and a first retard chamber 16r. That is, the first advance chamber 16a and the first retard chamber 16r are formed through the first vane 202 in the rotation direction, and are located between the shoes 122 of the housing 10 defining the first chamber 16.
A volume of the chamber 16a, 16r is varied by a flow of working liquid such as oil, and the first vane rotor 20 has relative rotation with respect to the housing 10. Specifically, the volume of the retard chamber 16r is reduced when working oil is discharged, and the volume of the advance chamber 16a is increased when working oil is introduced, so that the first vane rotor 20 has relative rotation with respect to the housing 10 in the advance direction. As a result, the first vane 202 is pressed against the shoe 122 in the advance direction, and the relative rotation phase of the first vane rotor 20 is restricted from being varied in the advance direction relative to the housing 10.
In contrast, the volume of the advance chamber 16a is reduced when working oil is discharged, and the volume of the retard chamber 16r is increased when working oil is introduced, so that the first vane rotor 20 has relative rotation with respect to the housing 10 in the retard direction. As a result, the first vane 202 is pressed against the shoe 122 in the retard direction, and the relative rotation phase of the first vane rotor 20 is restricted from being varied in the retard direction relative to the housing 10.
The second vane rotor 30 made of metal is accommodated between the accommodation plates 13 and 14 in the axis direction in the housing 10, and is slidably fitted with each of the plates 13 and 14. The second vane rotor 30 has a rotation shaft 300 and plural second vanes 302.
The cylindrical rotation shaft 300 is arranged on the inner side of the rotation wall 200 of the first vane rotor 20 in the radial direction, and is coaxially linked with the camshaft 2 in a state where the shaft 300 is slidably fitted with the wall 200. Therefore, the second vane rotor 30 rotates in the counterclockwise direction together with the camshaft 2 and is able to have relative rotation with respect to the first vane rotor 20 and the housing 10.
Each of the convex second vanes 302 is projected outward in the radial direction from the shaft 300, and the second vanes 302 are located with regular intervals in the rotation direction. The second vane 302 is accommodated and projected into the corresponding second accommodation chamber 26 so as to partition the chamber 26 in the rotation direction, so that the second vane 302 defines a second advance chamber 26a and a second retard chamber 26r. That is, the second advance chamber 26a and the second retard chamber 26r are formed through the second vane 302 in the rotation direction, and are located in the first vane 202 defining the second chamber 26.
A volume of the chamber 26a, 26r is varied by a flow of working oil, and the second vane rotor 30 has relative rotation with respect to the first vane rotor 20. Specifically, the volume of the retard chamber 26r is reduced when working oil is discharged, and the volume of the advance chamber 26a is increased when working oil is introduced, so that the second vane rotor 30 has relative rotation with respect to the first vane rotor 20 in the advance direction. As a result, the second vane 302 is pressed against an inner surface 202a of the first vane 202 in the advance direction, and the relative rotation phase of the second vane rotor 30 is restricted from being varied in the advance direction relative to the first vane rotor 20.
In contrast, the volume of the advance chamber 26a is reduced when working oil is discharged, and the volume of the retard chamber 26r is increased when working oil is introduced, so that the second vane rotor 30 has relative rotation with respect to the first vane rotor 20 in the retard direction. As a result, the second vane 302 is pressed against an inner surface 202r of the first vane 202 in the retard direction, and the relative rotation phase of the second vane rotor 30 is restricted from being varied in the retard direction relative to the first vane rotor 20.
The rotation control system 4 will be described with reference to
The control valve part 40 has an advance passage 42a, a retard passage 42r, a main supply passage 42ms, a drain passage 42d and a solenoid valve 44. A first end of the advance passage 42a is branched and communicates with each of the first advance chambers 16a. A first end of the retard passage 42r is branched and communicates with each of the first retard chambers 16r. The main supply passage 42ms communicates with a pump 6 which is a supply source of working oil. The pump 6 is a mechanical pump driven by the internal combustion engine through the crankshaft. While the engine is operated, the pump 6 pumps up working oil from a drain pan 7 and supplies the working oil to the main supply passage 42ms. The drain passage 42d is open to atmospheric air with the drain pan 7 as a drain collecting section, and is arranged to discharge working oil to the drain pan 7.
The solenoid valve 44 is a spool valve that reciprocates a spool 443 in a sleeve 442 using a driving force generated by energizing a solenoid 440 and a recovery force generated by elastic deformation of a coil spring 441 in a direction opposite from the driving force. The sleeve 442 of the solenoid valve 44 has an advance port 442a, a retard port 442r, a main supply port 442ms, a sub supply port 442ss, and a drain port 442d.
The advance port 442a communicates with the advance passage 42a. The retard port 442r communicates with the retard passage 42r. The main supply port 442ms communicates with the main supply passage 42ms. The sub supply port 442ss communicates with the second check valve part 60. The drain port 442d communicates with the drain passage 42d. The solenoid valve 44 allows or prohibits the communication among the ports 442a, 442r, 442ms, 442ss and 442d in accordance with the position of the spool 443 that is driven by controlling the solenoid 440.
Specifically, the advance port 442a communicates with the main supply port 442ms in the state where the spool 443 has moved to an advance position Pa of
In contrast, the retard port 442r communicates with the main supply port 442ms in the state where the spool 443 has moved to a retard position Pr of
Further in contrast, when the spool 443 is moved to a hold position Ph of
As shown in
As shown in
The check valve 64 is arranged in the middle of the sub supply passage 62ss. When the check valve 64 is opened, working oil flows from the sub supply port 442ss to the first switch valve part 70 through the sub supply passage 62ss. Thereby, each check valve 64 permits the forward feed of working oil which goes to the first switch valve part 70 from the sub supply port 442ss. On the other hand, the backward flow of working oil which goes to the sub supply port 442ss from the first switch valve part 70 is regulated by the check valve 64. Thereby, when the spool 443 is located at one of the positions Pa, Pr, and Ph, the check valve 64 permits the forward feed of working oil which goes to a supply point 720 of the first switch valve part 70 from the pump 6, and restricts the backward flow having the opposite flowing direction.
The switch valve part 70 has a switch passage 72 and a solenoid valve 74. A first end of the switch passage 72 is branched and communicates with each of the second advance chambers 26a. A second end of the switch passage 72 is branched and communicates with each of the second retard chambers 26r. The switch passage 72 connects the second advance chamber 26a and the second retard chamber 26r with each other. The supply point 720 of the first switch valve part 70 is arranged in the switch passage 72, and receives working oil from the sub supply passage 62ss by communicating with the sub supply passage 62ss of the second check valve part 60.
The solenoid valve 74 is arranged in the switch passage 72 at a position adjacent to the second end of the switch passage 72 rather than the supply point 720. In other words, the solenoid valve 74 is located adjacent to the second retard chamber 26r rather than the supply point 720. The solenoid valve 74 is driven by energizing the solenoid 740. Accordingly, the valve 74 allows the communication between the second advance chamber 26a and the second retard chamber 26r, as shown in
As shown in
Next, the variation torque which acts on the second vane rotor 30 of the rotation drive system 3 of the apparatus 1 is explained with reference to
Characteristic operation of the apparatus 1 will be described. The control circuit 80 switches a mode of adjusting the valve characteristics according to the operational status of the combustion engine between a timing adjustment mode and a working angle adjustment mode. In the timing adjustment mode, the valve timing is adjusted by maintaining the valve working angle. In the working angle adjustment mode, the valve working angle is adjusted by maintaining the valve timing such as valve-closing-operation finishing timing “tec” (see
When the apparatus 1 is set to have the timing adjustment mode, the circuit 80 controls the energizing of the solenoid 740 of the solenoid valve 74, thereby switching the switch passage 72 to prohibit the communication between the second advance chamber 26a and the second retard chamber 26r, as shown in
In the timing adjustment mode, when the negative torque Ta acts on the second vane rotor 30 in the advance direction from the camshaft 2, working oil of the second retard chamber 26r is pressurized by the second vane 302 in the first vane 202. At this time, the working oil of the second retard chamber 26r is restricted from flowing into the second advance chamber 26a through the switch passage 72 but is allowed to flow into the second advance chamber 26a through the check passage 52.
On the other hand, when the positive torque Tr acts on the second vane rotor 30 in the retard direction from the camshaft 2, the working oil of the second advance chamber 26a is pressurized by the second vane 302 in the first vane 202. At this time, the working oil of the second advance chamber 26a is restricted from flowing into the second retard chamber 26r through the switch passage 72 and is restricted from flowing into the second retard chamber 26r through the check passage 52.
As a result, working oil can be introduced into each second advance chamber 26a, and can be discharged from each second retard chamber 26r, respectively. Thereby, the second vane 302 of the second vane rotor 30 that has relative rotation in the advance direction relative to the first vane rotor 20 presses the internal surface 202a of the first vane 202 through the second retard chamber 26r from which the working oil is discharged, as shown in
Therefore, in the timing adjustment mode where the spool 443 is moved to one of the positions Pa, Pr, and Ph, the vane rotors 20 and 30 operate in the state where the second vane 302 is pressed to the first vane 202 in the advance direction. That is, at the advance position Pa of
Thus, in the timing adjustment mode, in response to the switchover control of working oil relative to each first advance chamber 16a and each first retard chamber 16r, the housing 10 and the second vane rotor 30 can be controlled to have a relative rotation phase, and a valve timing corresponding to the relative rotation phase can be realized. Accordingly, the valve timing can be mechanically accurately adjusted in the timing adjustment mode using the variation torque.
Furthermore in the timing adjustment mode, the check valve 64 restricts the working oil pressurized in the second advance chamber 26a by the positive torque Tr from flowing backward. That is, the working oil is restricted from flowing from the supply point 720 to the pump 6 through the switch passage 72. In contrast, when the negative torque Ta is applied, working oil can be supplied to the switch passage 72 through the supply point 720 from the pump 6 because the forward flow is permitted by the check valve 64.
At this time, the solenoid valve 74 intercepts the communication in a part of the switch passage 72 between the supply point 720 and the second retard chamber 26r. In contrast, working oil supplied to the supply point 720 can flow to the second advance chamber 26a in the other part of the switch passage 72 between the supply point 720 and the second advance chamber 26a. Therefore, even if the working oil introduced to the second advance chamber 26a is leaked out from a slide clearance between the vane rotors 20 and 30, working oil supplied to the supply point 720 can be supplied to the second advance chamber 26a from the switch passage 72.
Thus, the state where the second vane 302 is pressed to the first vane 202 can be maintained in the advance direction as a result of the backflow regulation and the supply function, so that reliability can be raised for the accurate valve timing adjustment that is mechanically realized in the state where the second vane 302 is pressed to the first vane 202.
In addition, at the timing adjustment mode, because the second vane 302 is disposed between the second advance chamber 26a and the second retard chamber 26r, the length of the check passage 52 can be made short, so that the pressure loss can be decreased. Therefore, time period necessary for pressing the second vane 302 to the first vane 202 can be made short, so that the accurate valve timing adjustment can be quickly started in the timing adjustment mode.
When the apparatus 1 is set to have the working angle adjustment mode, the control circuit 80 controls the energizing of the solenoid 740 of the solenoid valve 74, thereby switching the switch passage 72 to allow the communication between the second advance chamber 26a and the second retard chamber 26r, as shown in
The working angle adjustment mode is started from the state where the second vane 302 is pressed to the first vane 202 in the advance direction in the previous timing adjustment mode. Specifically, when the positive torque Tr acts on the second vane rotor 30 in the retard direction from the camshaft 2, working oil of the second advance chamber 26a is pressurized by the second vane 302. At this time, the working oil of the second advance chamber 26a is restricted from flowing into the second retard chamber 26r through the check passage 52, but is allowed to flow into the second retard chamber 26r through the switch passage 72, as shown in
Thus, the working oil is discharged from the second advance chamber 26a, and is introduced into the second retard chamber 26r. Thereby, as shown in a blank arrow direction of
Thus, the positive torque Tr is consumed by the relative rotation of the second vane rotor 30 in a direction restricting the rotation of the camshaft 2 until the second vane 302 is pressed to the first vane 202. In contrast, after the second vane 302 is pressed to the first vane 202, a force resisting to the positive torque Tr comes to act on the second vane rotor 30 and the camshaft 2 from the first vane rotor 20.
Accordingly, as shown in
Moreover, from the state of
Thus, working oil can be introduced into the second advance chamber 26a, and can be discharged from the second retard chamber 26r. Thereby, as shown in a blank arrow direction of
Therefore, the negative torque Ta is consumed by the relative rotation of the second vane rotor 30 in a direction assisting the rotation of the camshaft 2 until the second vane 302 is pressed to the first vane 202. In contrast, after the second vane 302 is pressed to the first vane 202, a force resisting to the negative torque Ta comes to act on the second vane rotor 30 and the camshaft 2 from the first vane rotor 20.
Accordingly, as shown in
Accordingly, from the start to the end of the working angle adjustment mode, while the valve-closing-operation finishing timing “tec” is maintained as shown in
If the blow-down pressure overlaps between the exhaust valve shown in the upper graph of
A valve characteristics control apparatus 2001 according to a second embodiment is a modification example of the first embodiment, and controls valve timing and valve working angle for plural intake valves having different opening/closing timings, as valve characteristics of a valve. The second vane rotor 30 rotating with the camshaft 2 that opens and closes the intake valve receives variation torque that is alternately varied between the positive torque Tr and the negative torque Ta, similarly to the first embodiment shown in
When the apparatus 2001 is set to have the working angle adjustment mode, the control circuit 2080 controls the energizing of the solenoid 440 of the solenoid valve 44, thereby switching the position of the spool 443 to the advance position Pa, as shown in
The working angle adjustment mode is started from the state where the second vane 302 is pressed to the first vane 202 in the advance direction in the previous timing adjustment mode. In accordance with the start of the working angle adjustment mode, the spool 443 is moved to the advance position Pa of
In
After the advance operation of
Accordingly, as shown in
In an upper graph of
In contrast, as shown in
From the complete of the advance operation shown in
Thus, as shown in
A valve characteristics control apparatus 3001 according to a third embodiment is a modification example of the first embodiment, and controls valve timing and valve working angle for plural intake valves having different opening/closing timings, as valve characteristics of a valve. The second vane rotor 30 rotating with the camshaft 2 that opens and closes the intake valve receives variation torque that is alternately varied between the positive torque Tr and the negative torque Ta, similarly to the first embodiment shown in
As shown in
When the apparatus 3001 is set to have the timing adjustment mode, similarly to the first embodiment, the control circuit 80 controls the energizing of the solenoid 740, 440, thereby switching the switch passage 72 to prohibit the communication between the second advance chamber 26a and the second retard chamber 26r, as shown in
In the timing adjustment mode, when the positive torque Tr acts on the second vane rotor 30 in the retard direction from the camshaft 2, working oil of the second advance chamber 26a is pressurized by the second vane 302 in the first vane 202. At this time, the working oil of the second advance chamber 26a is restricted from flowing into the second retard chamber 26r through the switch passage 72 but is allowed to flow into the second retard chamber 26r through the check passage 52.
On the other hand, when the negative torque Ta acts on the second vane rotor 30 in the advanced direction from the camshaft 2, the working oil of the second retard chamber 26r is pressurized by the second vane 302 in the first vane 202. At this time, the working oil of the second retard chamber 26r is restricted from flowing into the second advance chamber 26a through the switch passage 72 and is restricted from flowing into the second advance chamber 26a through the check passage 52.
As a result, working oil can be discharged from each second advance chamber 26a, and can be introduced into each second retard chamber 26r, respectively. Thereby, the second vane 302 of the second vane rotor 30 that has relative rotation in the retard direction relative to the first vane rotor 20 presses the internal surface 202r of the first vane 202 through the second advance chamber 26a from which the working oil is discharged, as shown in
Therefore, in the timing adjustment mode where the spool 443 is moved to one of the positions Pa, Pr, and Ph, the vane rotors 20 and 30 operate in the state where the second vane 302 is pressed to the first vane 202 in the retard direction. That is, at the advance position Pa of
Thus, in the timing adjustment mode, in response to the switchover control of working oil relative to each first advance chamber 16a and each first retard chamber 16r, the housing 10 and the second vane rotor 30 can be controlled to have a relative rotation phase, and a valve timing corresponding to the relative rotation phase can be realized. Accordingly, the valve timing can be mechanically accurately adjusted in the timing adjustment mode using the variation torque.
Furthermore in the timing adjustment mode, the check valve 64 restricts the working oil pressurized in the second retard chamber 26r by the negative torque Ta from flowing backward. That is, the working oil is restricted from flowing from the supply point 720 to the pump 6 through the switch passage 72. In contrast, when the positive torque Tr is applied, working oil can be supplied to the switch passage 72 through the supply point 720 from the pump 6 because the forward flow is permitted by the check valve 64.
At this time, the solenoid valve 74 intercepts the communication in a part of the switch passage 72 between the supply point 720 and the second advance chamber 26a. In contrast, working oil supplied to the supply point 720 can flow to the second retard chamber 26r in the other part of the switch passage 72 between the supply point 720 and the second retard chamber 26r. Therefore, even if the working oil introduced to the second retard chamber 26r is leaked out from the slide clearance between the vane rotors 20 and 30, working oil supplied to the supply point 720 can be supplied to the second retard chamber 26r from the switch passage 72.
Thus, the state where the second vane 302 is pressed to the first vane 202 can be maintained in the retard direction as a result of the backflow regulation and the supply function, so that reliability can be raised for the accurate valve timing adjustment that is mechanically realized in the state where the second vane 302 is pressed to the first vane 202.
In addition, at the timing adjustment mode, because the second vane 302 is disposed between the second advance chamber 26a and the second retard chamber 26r, the length of the check passage 52 can be made short, so that the pressure loss can be decreased. Therefore, the accurate valve timing adjustment can be quickly started in the timing adjustment mode.
When the apparatus 3001 is set to have the working angle adjustment mode, similarly to the first embodiment, the control circuit 80 controls the energizing of the solenoid 740, 440, thereby switching the switch passage 72 to allow the communication between the second advance chamber 26a and the second retard chamber 26r, as shown in
The working angle adjustment mode is started from the state where the second vane 302 is pressed to the first vane 202 in the retard direction in the previous timing adjustment mode. Specifically, when the negative torque Ta acts on the second vane rotor 30 in the advance direction from the camshaft 2, working oil of the second retard chamber 26r is pressurized by the second vane 302. At this time, the working oil of the second retard chamber 26r is restricted from flowing into the second advance chamber 26a through the check passage 52, but is allowed to flow into the second advance chamber 26a through the switch passage 72, as shown in
Thus, the working oil is introduced into the second advance chamber 26a, and is discharged from the second retard chamber 26r. Thereby, as shown in a blank arrow direction of
Thus, the negative torque Ta is consumed by the relative rotation of the second vane rotor 30 in a direction assisting the rotation of the camshaft 2 until the second vane 302 is pressed to the first vane 202. In contrast, after the second vane 302 is pressed to the first vane 202, a force resisting to the negative torque Ta comes to act on the second vane rotor 30 and the camshaft 2 from the first vane rotor 20.
Accordingly, as shown in
Moreover, from the state of
Thus, working oil can be discharged from the second advance chamber 26a, and can be introduced into the second retard chamber 26r. Thereby, as shown in a blank arrow direction of
Therefore, the positive torque Tr is consumed by the relative rotation of the second vane rotor 30 in a direction restricting the rotation of the camshaft 2 until the second vane 302 is pressed to the first vane 202. In contrast, after the second vane 302 is pressed to the first vane 202, a force resisting to the positive torque Tr comes to act on the second vane rotor 30 and the camshaft 2 from the first vane rotor 20.
Accordingly, as shown in
Accordingly, from the start to the end of the working angle adjustment mode, while the valve-opening-operation starting timing “tio” is maintained as shown in
Thus, similarly to the second embodiment shown in
A valve characteristics control apparatus 4001 according to a fourth embodiment is a modification example of the third embodiment, and controls valve timing and valve working angle for plural exhaust valves having different opening/closing timings, as valve characteristics of a valve. The second vane rotor 30 rotating with the camshaft 2 that opens and closes the intake valve receives variation torque that is alternately varied between the positive torque Tr and the negative torque Ta, similarly to the first embodiment shown in
When the apparatus 4001 is set to have the working angle adjustment mode, the control circuit 4080 controls the energizing of the solenoid 440 of the solenoid valve 44, thereby switching the position of the spool 443 to the retard position Pr, as shown in
The working angle adjustment mode is started from the state where the second vane 302 is pressed to the first vane 202 in the retard direction in the previous timing adjustment mode that is realized similarly to the third embodiment. In accordance with the start of the working angle adjustment mode, the spool 443 is moved to the retard position Pr of
In
After the retard operation of
Accordingly, as shown in
In an upper graph of
In contrast, as shown in
From the complete of the retard operation of
Thus, when the valve-opening-operation starting timing “teo” is maintained and when the valve working angle “φe” is reduced, similarly to the first embodiment shown in
If the blow-down pressure overlaps between the exhaust valve shown in the upper graph of
While the present disclosure has been described with reference to preferred embodiments thereof, it is to be understood that the disclosure is not limited to the preferred embodiments and constructions. The present disclosure is intended to cover various modification and equivalent arrangements. In addition, while the various combinations and configurations, which are preferred, other combinations and configurations, including more, less or only a single element, are also within the spirit and scope of the present disclosure.
Specifically, the valve characteristics control apparatus 1, 4001 of the first and fourth embodiment may be applied to only one exhaust valve or at least one intake valve. Further, the valve characteristics control apparatus 2001, 3001 of the second and third embodiment may be applied to only one intake valve or at least one exhaust valve.
Further, in the working angle adjustment mode of the apparatus 2001, 4001 of the second and fourth embodiment, the communication between the second advance chamber 26a and the second retard chamber 26r through the switch passage 72 may be intercepted when the position of the spool 443 is switched to the advance position Pa or the retard position Pr before the position of the spool 443 is switched to the hold position Ph.
Furthermore, the above operation and advantage can be obtained if the first check valve part 50, 3050 is disposed in at least one second vane 302 in the first to fourth embodiments. Otherwise, the first check valve part 50, 3050 may be disposed in other part of the second vane rotor 30 other than the second vane 302, or may be disposed outside of the second vane rotor 30.
In addition, the main supply passage 42ms and the sub supply passage 62ss may be made to communicate with each other not through the port 442ms, 442ss in the first to fourth embodiments.
Such changes and modifications are to be understood as being within the scope of the present disclosure as defined by the appended claims.
Number | Date | Country | Kind |
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2011-147821 | Jul 2011 | JP | national |