The present disclosure relates generally to motor vehicle camshaft phaser and more specifically to fluid systems in motor vehicle drivetrains.
Hydraulic cam phasers utilize a mechanical locking pin to hold a camshaft phaser in a fixed position during engine shutdown or a failsafe scenario.
A camshaft phaser for an internal combustion engine includes a stator defining a receptacle therein. The stator includes a ring and a plurality of webs extending radially inward from the ring. The camshaft phaser also includes a rotor rotatable with respect to the stator and received inside the receptacle. The rotor includes a center section and a plurality of vanes extending radially outward from the center section. The center section abuts the webs to define chambers circumferentially between the webs. Each of the vanes is positioned in one of the chambers and sealingly engaging an inner circumferential surface of the ring. At least one of the chambers is a locking chamber and at least one the vanes is a locking vane positioned in the locking chamber. The camshaft phaser also includes a locking valve in the locking vane configured to allow fluid to enter into the locking chamber and to prevent fluid from flowing out of the locking chamber to lock the rotor with respect to the stator in a locked orientation.
In examples, the locking vane includes a locking port extending from the center section to the locking valve to provide fluid through the locking valve into the locking chamber.
In examples, the locking vane further includes a first pressurization port extending from the center section through the locking vane and configured for supplying fluid in a first circumferential direction into the locking chamber.
In examples, the locking vane further includes a second pressurization port extending from the center section through the locking and configured for supplying fluid in a second circumferential direction into the locking chamber, the second circumferential direction being opposite of the first circumferential direction.
In examples, the camshaft phaser is configured to set a rotational configuration of the rotor during operation of the camshaft phaser by supplying fluid to at least one of the first pressurization port and the second pressurization port.
In examples, the camshaft phaser is configured to lock the rotor with respect to the stator in a locked orientation during engine shutdown or a failsafe scenario of the camshaft phaser by supplying fluid to the locking port.
In examples, the locking port is configured for supplying fluid in the second circumferential direction into the locking chamber.
In examples, the locking valve is a check valve.
In examples, in the locking position, the locking vane is positioned circumferentially in contact with one of the webs delimiting the locking chamber.
In examples, the camshaft phaser does not include a mechanical locking device for rotationally fixing the rotor in place with respect to the stator.
In examples, the camshaft phaser further includes a control valve for controlling a flow of pressurized fluid from a pump into the locking port, the locking valve configured for being in locked position when the control valve is in a deactivated orientation.
In examples, the camshaft phaser further includes a first pressurization port extending from the center section through the locking vane and configured for supplying fluid in a first circumferential direction into the locking chamber; and a second pressurization port extending from the center section through the locking and configured for supplying fluid in a second circumferential direction into the locking chamber, the second circumferential direction being opposite of the first circumferential direction, the control valve being selectively actuatable to control the flow of pressurized fluid from the pump into the locking port, the first pressurization port and the second pressurization port.
In examples, the control valve is configured to fluidically connect the locking port to the pump when the control valve is in the deactivated orientation.
In examples, the control valve is configured to fluidically connect the first pressurization port to the pump when the control valve is in a first activated orientation, and the control valve is configured to fluidically connect the second pressurization port to the pump when the control valve is in a second activated orientation.
In examples, a valve body of the control valve is in: an initial position in the deactivated orientation of the control valve, a first position that is a first distance from the initial position in the first activated orientation of the control valve, and a second position that is a second distance from the initial position in the second activated orientation in the first activated orientation.
In examples, the second pressurization port is connected to a fluid tank in the deactivated orientation of the control valve.
In examples, the first pressurization port and the second pressurization port are disconnected from the pump in the deactivated orientation of the control valve.
In examples, the second pressurization port is disconnected from the pump in the first activated orientation of the control valve, and the first pressurization port is disconnected from the pump in the second activated orientation of the control valve.
In examples, the control valve includes a solenoid actuator and the solenoid actuator is de-energized in the deactivated orientation of the control valve.
A method of operating the camshaft phaser can include energizing the solenoid actuator to move the control valve into a first activated orientation to hydraulically displace the rotor in a first circumferential direction, and/or energizing the solenoid actuator to move the control valve into a second activated orientation to hydraulically displace the rotor in a second circumferential direction opposite the first circumferential direction; and de-energizing the solenoid actuator, the de-energizing of the solenoid actuator causing fluid to flow through the control valve into the locking chamber to lock the rotor with respect to the stator.
The present disclosure is described below by reference to the following drawings, in which:
The camshaft phase 10 also includes a locking valve 28 in the locking vane 24a configured to allow fluid to enter into the locking chamber 26a and to prevent fluid from flowing out of the locking chamber 26a to lock the rotor 16 with respect to the stator 12 in a locked orientation. In the embodiment shown in
The locking vane 24a includes a locking port 30 extending from the center section 22 to the locking valve 28 to provide fluid through the locking valve 28 into the chamber. The locking vane 24a further includes a first pressurization port 32 extending radially from an interior of the center section 22 to the outer circumferential surface 22a of the center section 22 and configured for supplying fluid into the area of locking chamber 26a facing a first circumferentially facing side 24b of the locking vane 24a, and a second pressurization port 34 extending radially from an interior of the center section 22 to the outer circumferential surface 22a of the center section 22 and configured for supplying fluid into the area of locking chamber 26a facing a second circumferentially facing side 24c of the locking vane 24a.
The camshaft phaser 10 is configured to set a rotational configuration of the rotor 16 during operation of the camshaft phaser 10 by selectively supplying fluid to at least one of the first pressurization port 32 and the second pressurization port 34. The fluid supplied to the first pressurization port 32 flows into the area of locking chamber 26a facing the first circumferentially facing side 24b of the locking vane 24a, which cause the locking vane 24a, and the rotor 16 as a whole, to rotate in a second circumferential direction D2. The fluid supplied to the second pressurization port 34 flows into the area of locking chamber 26a facing a second circumferentially facing side 24c of the locking vane 24a, which cause the locking vane 24a, and the rotor 16 as a whole, to rotate in a first circumferential direction D1 opposite of the second circumferential direction D2.
The camshaft phaser 10 is also configured to lock the rotor 16 with respect to the stator 12 in a locked orientation during engine shutdown or a failsafe scenario of the camshaft phaser 10 by supplying fluid to the locking port 30. A failsafe scenario is defined as a scenario when power is not provided to the control valve 36 of camshaft phaser 10. The locking port 30 is configured for supplying fluid into the locking chamber 26a. In the locking position, the locking vane 24a is positioned circumferentially in contact with one of the webs 20 delimiting the locking chamber 26a. In particular, in the locking position, the locking vane 24a is positioned circumferentially in contact with the web 20 facing the second circumferentially facing side 24c of the locking vane 24a.
As shown schematically in
Valve body 40 has a cylindrical base 42 including a plurality of disc shaped blocking sections 44 extending radially outward from the base 42. Blocking sections 44 are aligned with port openings formed in an inner circumferential surface 16a of rotor 16. In particular, inner circumferential surface 16a includes a first pump opening 46a, a second pump opening 46b, a locking port opening 46c, a first pressurization port opening 46d and a second pressurization port opening 46e. The valve body 40 is positioned within a bore 16b, which is defined by inner circumferential surface 16a, and bore 16b is connected to a fluid tank 48. Pump 38 pumps fluid from the fluid tank 48. First pump opening 46a and second pump opening 46b are fluidically coupled to pump 38 for pumping fluid into ports 32, 34, 36 via locking port opening 46c, first pressurization port opening 46d and second pressurization port opening 46e depending on the orientation of control valve 36. Depending on the position of valve body 40, the fluid can also flow out of first pressurization port 32 and second pressurization port 34 into the fluid tank 48.
Control valve 36 further includes an electromagnetic actuator 50 for moving valve body 40 linearly, and a return spring 52 for returning valve body 40 to a setpoint position when electromagnetic actuator 50 is de-energized. Electromagnetic actuator 50 is a solenoid actuator and includes a coil that is energized to create a magnetic field, which pulls a plunger or a piston to move valve body 40. Electromagnetic actuator 50 can be controlled by a controller 54. For example, control valve 36 can be controlled by controller 54 to multiple positions by using pulse width modulation (PWM). In the example shown in
As shown schematically in
As shown schematically in
As shown schematically in
As shown schematically in
Referring to all of the figures together, a method of operating the camshaft phaser 10 includes energizing the control valve 36 to hydraulically displace the rotor 16 in a first circumferential direction, and/or energizing the control valve 36 to hydraulically displace the rotor 16 in a second circumferential direction opposite the first circumferential direction. The method also includes de-energizing the control valve 36. The de-energizing of the control valve 36 causes fluid to flow through the control valve 36 into the locking chamber 26a to lock the rotor 16 with respect to the stator 12.
In the preceding specification, the present disclosure has been described with reference to specific exemplary embodiments and examples thereof. It will, however, be evident that various modifications and changes may be made thereto without departing from the broader spirit and scope of present disclosure as set forth in the claims that follow. The specification and drawings are accordingly to be regarded in an illustrative manner rather than a restrictive sense.
Number | Name | Date | Kind |
---|---|---|---|
6644258 | Smith | Nov 2003 | B1 |
6647936 | Lewis | Nov 2003 | B2 |
6684835 | Komazawa et al. | Feb 2004 | B2 |
6761138 | Takahashi | Jul 2004 | B2 |
8356583 | Smith | Jan 2013 | B2 |
9638109 | Watanabe | May 2017 | B2 |
9957851 | Takahata et al. | May 2018 | B2 |
10598053 | Moetakef | Mar 2020 | B2 |
11015491 | Nichols et al. | May 2021 | B2 |
20020129781 | Kinugawa | Sep 2002 | A1 |
20070107684 | Takahashi | May 2007 | A1 |
20130180486 | Smith | Jul 2013 | A1 |
20210277808 | Kenyon | Sep 2021 | A1 |
Number | Date | Country |
---|---|---|
102012209602 | Dec 2012 | DE |
102015106262 | Sep 2016 | DE |