Hybrid phaser with hydraulic lock in an intermediate position

Patent metadata

Field	Value
Publication number	US-11725546-B2
Application number	US-201917273909-A
Country	US
Kind code	B2
Filing date	Sep 13, 2019
Priority date	Sep 13, 2018
Publication date	Aug 15, 2023
Grant date	Aug 15, 2023

Abstract

A phaser which has an offset or remote pilot valve added to the hydraulic circuit to manage a hydraulic detent switching function, in order to provide a mid-position lock for cold starts of the engine, either during cranking or prior to complete engine shutdown. The mid-position locking of the phaser positions the cam at an optimum position for cold restarts of the engine.

First claim

What is claimed is:

1. A variable cam timing phaser comprising:
a housing assembly having an outer circumference for accepting drive force, the housing assembly comprising a first end plate and a second end plate, the first end plate or the second end plate having a pair of end plate metered pockets;
a rotor assembly to connect to a camshaft, the rotor assembly coaxially located within the housing assembly, the rotor assembly having a rotor body with at least one vane extending therefrom, a rotor advance metered pocket and a rotor retard metered pocket, wherein the housing assembly and the rotor assembly define at least one chamber separated by the at least one vane into an advance chamber and a retard chamber, the at least one chamber defined by an advance wall and a retard wall, the at least one vane within the at least one chamber acting to shift relative angular position of the housing assembly, the rotor assembly, and the at least one vane;
a control valve for directing fluid from a fluid input to and from the advance chamber and the retard chamber through an advance line, a retard line, a supply line coupled to the fluid input, at least two tunable exhaust ports in communication with a tank, an advance detent line and a retard detent line, the control valve being moveable through multiple modes comprising:
an advance mode in which fluid is routed from the fluid input to the advance chamber, and fluid is routed from the retard chamber to one of the at least two tunable exhaust ports and to the advance chamber through a retard recirculation check valve;
a retard mode in which fluid is routed from the fluid input to the retard chamber, and fluid is routed from the advance chamber to one of the at least two tunable exhaust ports and to the retard chamber through an advance recirculation check valve;
a holding position in which fluid is routed to the advance chamber and the retard chamber from the supply line; and
a detent mode in which the control valve blocks fluid from exiting the retard chamber through the control valve, retaining fluid within the retard chamber, and blocks fluid from exiting the advance chamber through the control valve, retaining fluid within the advance chamber; and

a pilot valve in fluid communication with the control valve, the rotor advance metered pocket via the advance detent line, and the rotor retard metered pocket via the retard detent line, the pilot valve moveable between a first position in which fluid from the control valve can flow through the pilot valve to the rotor advance metered pocket and the rotor retard metered pocket and a second position in which fluid is prevented from flowing from the control valve through the pilot valve to the rotor advance metered pocket and the rotor retard metered pocket,
wherein when the control valve is in the detent mode, the pilot valve is in the first position, the at least one vane is positioned within the housing assembly near or in an advance position, fluid from the advance chamber flows to the control valve, through the retard recirculation check valve, through the pilot valve, and into the retard detent line, fluid from the retard detent line flows into the rotor retard metered pocket aligned with the end plate metered pockets and into the retard chamber, moving the at least one vane until the rotor retard metered pocket and the end plate metered pockets are misaligned and the variable cam timing phaser is in a mid-position between the advance wall and the retard wall within the at least one chamber,
wherein when the control valve is in the detent mode, the pilot valve is in the first position, the at least one vane is positioned within the housing assembly near or in a retard position, fluid from the retard chamber flows to the control valve, through the advance recirculation check valve, through the pilot valve, and into the advance detent line, fluid from the advance detent line flows into the rotor advance metered pocket aligned with the end plate metered pockets and into the advance chamber, moving the at least one vane until the rotor advance metered pocket and the end plate metered pockets are misaligned and the variable cam timing phaser is in the mid-position between the advance wall and the retard wall within the at least one chamber.

2. The variable cam timing phaser of claim 1 , wherein the rotor advance metered pocket and the rotor retard metered pocket are located within the at least one vane.

3. The variable cam timing phaser of claim 1 , wherein the rotor advance metered pocket and the rotor retard metered pocket are located within the rotor body of the rotor assembly.

4. The variable cam timing phaser of claim 1 , wherein the control valve is located within the rotor assembly.

5. The variable cam timing phaser of claim 1 , wherein the control valve further comprises:
a hollow sleeve with a plurality of ports and the at least two tunable exhaust ports; and
a spool received within the hollow sleeve comprising:
a plurality of lands for selectively blocking the plurality of ports and the at least two tunable exhaust ports of the hollow sleeve; and
a working central passage located within the spool receiving the advance recirculation check valve and the retard recirculation check valve, limiting a flow of fluid between the advance chamber and the retard chamber through the working central passage.

6. The variable cam timing phaser of claim 1 , further comprising a locking pin slidably located in a bore of the rotor assembly, the locking pin being moveable within the rotor assembly from a locked position in which an end portion of the locking pin engages a recess of the housing assembly, to an unlocked position in which the end portion does not engage the recess of the housing assembly, the recess being in fluid communication with the pilot valve and in fluid communication with the supply line via the control valve.

7. The variable cam timing phaser of claim 1 , wherein the advance recirculation check valve and the retard recirculation check valve are located outside of the control valve.

8. The variable cam timing phaser of claim 1 , wherein the at least two tunable exhaust ports are sized to alter fluid flow from the retard chamber to the tank and from the advance chamber to the tank when the control valve is in the advance mode and in the retard mode, and to alter an amount of fluid recirculating between the advance chamber and the retard chamber.

9. A variable cam timing phaser comprising:
a housing assembly having an outer circumference for accepting drive force, the housing assembly comprising a first end plate and a second end plate, the first end plate or the second end plate having a pair of end plate metered pockets;
a rotor assembly to connect to a camshaft, the rotor assembly coaxially located within the housing assembly, the rotor assembly having a rotor body with at least one vane extending therefrom and a rotor advance metered pocket and a rotor retard metered pocket, wherein the housing assembly and the rotor assembly define at least one chamber separated by the at least one vane into an advance chamber and a retard chamber, the at least one chamber defined by an advance wall and a retard wall, the at least one vane within the at least one chamber acting to shift relative angular position of the housing assembly and the rotor assembly and the at least one vane;
a control valve for directing fluid from a fluid input to and from the advance chamber and the retard chamber through an advance line, a retard line, a supply line coupled to the fluid input, an exhaust port in communication with a tank, an advance detent line and a retard detent line, the control valve being moveable through multiple modes comprising:
an advance mode

Assignees

• Borgwarner Inc

Inventors

• Kenyon Brian

Classifications

• F01L1/3442 Primary

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

• F01L2001/3443

  Solenoid driven oil control valves · CPC title

• F01L2001/34433

  Location oil control valves · CPC title

• F01L2001/34469

  Lock movement parallel to camshaft axis · CPC title

• F01L2250/02

  the camshaft being driven by chains · CPC title