Multi-mode variable camshaft timing device with two locking positions

Patent metadata

Field	Value
Publication number	US-10344632-B2
Application number	US-201715714469-A
Country	US
Kind code	B2
Filing date	Sep 25, 2017
Priority date	Aug 31, 2015
Publication date	Jul 9, 2019
Grant date	Jul 9, 2019

Abstract

A system including a phaser with a first lock pin and a second lock pin in the rotor assembly. The first and second locks pins having a locked position where they engage a recess in the housing assembly and an unlocked position in which they do not engage the housing assembly. The first lock pin locks the rotor assembly to the housing assembly when the phaser is in an intermediate phase angle position. The second lock pin locks the rotor assembly to the housing assembly when the phaser is at a full retard position. The control valve includes a recirculation check valve and an inlet check valve.

First claim

What is claimed is:

1. A variable cam timing system including a phaser for an internal combustion engine including a housing assembly with an outer circumference for accepting drive force and a rotor assembly coaxially located within the housing for connection to a camshaft, having a plurality of vanes, wherein the housing assembly and the rotor assembly define at least one chamber separated by a vane of the plurality of vanes into an advance working chamber with an advance wall and a retard working chamber with a retard wall, the vane of the plurality of vanes within the chamber acting to shift relative angular position of the housing assembly and the rotor assembly when fluid is supplied to the advance working chamber or the retard working chamber, the variable cam timing system further comprising:
a control valve for directing fluid from a fluid input to and from the advance working chamber and the retard working chamber through an advance line, a retard line, a supply line coupled to the fluid input, and a vent;
the control valve being moveable through multiple modes comprising: an advance mode in which fluid is routed from the fluid input to the advance working chamber and fluid is routed from the retard working chamber to a vent and to the advance working chamber through a recirculation check valve, a retard mode in which fluid is routed from the fluid input to the retard working chamber and fluid is routed from the advance working chamber to the vent and to the retard working chamber through the recirculation check valve; a holding position in which fluid is routed to the advance working chamber and the retard working chamber, a first locking mode associated with the locking of a first lock pin and a second locking mode associated with the locking of a second lock pin, wherein during at least one of the first and second locking modes, the vane is adjacent to the advance wall or the retard wall;
the first lock pin slidably located in the rotor assembly, the first lock pin being moveable within the rotor assembly from a locked position in which an end portion of the first lock pin engages a first recess of the housing assembly, to an unlocked position in which the end portion does not engage the first recess of the housing assembly, the first recess in fluid communication with the supply line; and
the second lock pin slidably located in the rotor assembly and in communication with either of the advance working chamber or the retard working chamber through a lock port, the second lock pin being moveable within the rotor assembly from a locked position in which an end portion of the second lock pin engages a second recess of the housing assembly through pressure from either the retard working chamber or advance working chamber via the lock port, to an unlocked position in which the end portion is spring biased to not engage the second recess of the housing assembly;
wherein when the control valve is in the second locking mode, fluid from the advance working chamber or the retard working chamber flows through the lock port to move the second lock pin to a locked position, locking the relative angular position of the housing assembly and the rotor assembly and the first lock pin is moved to an unlocked position by pressure supplied from the supply line.

2. The system of claim 1 , wherein the control valve further comprises:
a hollow sleeve with a plurality of ports, where at least two of the ports are connected by a recirculation recess; and
a spool received within the hollow sleeve comprising:
a plurality of lands for selectively blocking the plurality of ports of the hollow sleeve;
a working central passage located within the spool;
an inlet passage located within the spool;
the recirculation check valve received within the working central passage, limiting the flow of fluid between the first and second chambers through the working central passage; and
an inlet check valve received within the inlet central passage, allowing fluid from the fluid input to flow to the first and second chambers, and preventing flow from the first and second chambers to the fluid input during cam torque reversals;

wherein in the advance mode fluid is routed from the fluid input, through the inlet check valve to the advance working chamber and from the retard working chamber through the recirculation recess of the sleeve and the recirculation check valve to the advance working chamber.

3. The system of claim 2 , wherein recirculation check valve comprises a plate, a spring retainer, a valve seat, and a spring with a first end attached to the plate and a second end attached to the spring retainer.

4. The system of claim 2 , wherein the inlet check valve comprises a ball, a valve seat, a spring retainer, and a spring with a first end attached to the ball and a second end attached to the spring retaining member, wherein the ball blocks the flow of fluid through a passage connected to the inlet passage.

5. The system of claim 1 , wherein the control valve is further moveable to a detent mode and wherein when the control valve is in the detent mode, the control valve blocks fluid from exiting from the retard working chamber through the control valve, retaining fluid within the retard working chamber, blocking the supply line to the first recess, such that the first lock pin engages the first recess of the housing assembly, locking the relative angular position of the housing assembly and the rotor assembly.

6. The system of claim 5 , wherein when the control valve is moved to the detent mode, the second lock pin is moved to the unlocked position.

7. The system of claim 5 , further comprising a detent circuit that is switchable from an open position to a closed position, wherein when the detent circuit is in the open position, the detent circuit moves the vane to an intermediate position within the at least one chamber defined by the housing assembly and the rotor assembly.

8. The system of claim 7 , wherein when the detent circuit is in a closed position, the control valve is moved to the oil pressure actuated mode and fluid flows through the control valve to oil pressure actuate the advance and retard working chambers.

9. The system of claim 8 , wherein when the detent circuit is open, fluid is allowed to flow between an advance detent line to at least one advance working chamber and a retard detent line to at least one retard working chamber and a common line in fluid communication with the advance working chamber and the retard working chamber with advance and retard check valves, such that the rotor assembly is moved through cam torque actuation of at least one advance working chamber and at least one retard working chamber and held in an intermediate phase angle position relative to the housing assembly.

10. The system of claim 8 , wherein the detent circuit is switchable between the open position and the closed position through a piloted valve.

11. The system of claim 10 , wherein the piloted valve further comprises a spool have a first end and second end, wherein the first end is the first lock pin and fits in the first recess.

12. The system of claim 1 , wherein when the control valve is moved towards the advance mode, the retard mode, or the holding position, the first lock pin is moved to the unlocked position.

13. The system of claim 1 , wherein the control valve further comprises an inlet check valve.

14. The system of claim 1 , wherein the first recess is in an inner end plate of the housing assembly and the second recess is in an outer end plate of the housing assembly.

15. The system of claim 1 , wherein the control valve is lo

Assignees

• Borgwarner Inc

Inventors

• Smith Franklin R

Classifications

• F01L2001/34426

  Oil control valves · CPC title

• F01L2001/3443

  Solenoid driven oil control valves · CPC title

• F01L2250/02

  the camshaft being driven by chains · CPC title

• F01L2001/34453

  Locking means between driving and driven members · CPC title

• F01L1/047

  Camshafts · CPC title