Camshaft adjustment system for flexibly starting an internal combustion engine, and method for operating a drivetrain

Patent metadata

Field	Value
Publication number	US-12535019-B2
Application number	US-202218570973-A
Country	US
Kind code	B2
Filing date	Jun 7, 2022
Priority date	Jun 16, 2021
Publication date	Jan 27, 2026
Grant date	Jan 27, 2026

Abstract

The disclosure relates to a camshaft adjustment system comprising a hydraulic camshaft adjuster having a stator and a rotor forming at least one working chamber. The at least one working chamber is divided into a first sub-chamber and a second sub-chamber The sub-chambers interact with a control valve controllable via a first actuator. When the first sub-chamber undergoes a volume increase, the rotor is displaced into a late position relative to the stator, and when the second sub-chamber undergoes a volume increase, the rotor is displaced into an early position relative to the stator. A second actuator actuated independently of the first actuator is provided. In order to release the camshaft adjuster from the late position when in an operating state, a ram of the second actuator displaces a locking pin of a late-locking device of the camshaft adjuster out of its position that locks the late position.

First claim

The invention claimed is:

1 . A camshaft adjustment system, comprising:
a hydraulic camshaft adjuster having at least one working chamber formed between a stator and a rotor, the rotor configured to be rotatable relative to the stator, and at least one of the at least one working chamber is divided into a first sub-chamber and a second sub-chamber, and the first sub-chamber and the second sub-chamber are fluidly connected with a control valve controllable via a first actuator, such that: i) when the first sub-chamber undergoes a volume increase, the rotor is displaced into a late position relative to the stator, and ii) when the second sub-chamber undergoes a volume increase, the rotor is displaced into an early position relative to the stator, and a second actuator actuated independently of the first actuator, the second actuator electronically controlled and having a ram configured to displace a locking pin of a late-locking device of the hydraulic camshaft adjuster so as to release the hydraulic camshaft adjuster from a locked late position when the hydraulic camshaft adjuster is in an operating state.

2 . The camshaft adjustment system according to claim 1 , wherein the hydraulic camshaft adjuster is configured such that when a hydraulic pressure falls below a minimum hydraulic pressure, the hydraulic camshaft adjuster is automatically rotated into a predetermined starting position relative to the second actuator in which the ram is coupled in an axially displaceable manner to the locking pin.

3 . The camshaft adjustment system according to claim 1 , wherein the late-locking device is configured such that when a hydraulic pressure of the hydraulic camshaft adjuster falls below a minimum hydraulic pressure, the rotor is displaced into the late position and the locking pin of the late-locking device automatically locks the rotor in a rotationally fixed manner relative to the stator ( 4 ).

4 . The camshaft adjustment system according to claim 1 , wherein the ram is indirectly axially coupled to the locking pin via an axially displaceable sliding element slidably accommodated in the stator.

5 . The camshaft adjustment system according to claim 4 , wherein at least one of the ram or the axially displaceable sliding element is preloaded by a return spring to a rest position.

6 . The camshaft adjustment system according to claim 4 , wherein the ram is coupled to the axially displaceable sliding element via a plate, and two arms of the plate extending to opposite peripheral sides are arranged at a same radial position as the axially displaceable sliding element relative to an axis of rotation of the hydraulic camshaft adjuster.

7 . The camshaft adjustment system according to claim 6 , wherein the hydraulic camshaft adjuster further comprises a central locking device configured for locking the rotor relative to the stator in at least one center position offset from the late position towards the early position.

8 . The camshaft adjustment system according to claim 7 , wherein the central locking device forms a multi-stage ratchet.

9 . A method for operating a drive train having a camshaft adjustment system according to claim 1 , wherein: i) the stator is rotatably coupled to a crankshaft of an internal combustion engine via a timing drive, ii) the rotor is attached to a camshaft of the internal combustion engine, and an electric machine is operatively connected to the crankshaft, wherein the method comprises:
unlocking the late-locking device supporting the rotor in the late position relative to the stator via activating the second actuator, and rotating the crankshaft via the electric machine such that the stator and the rotor of the hydraulic camshaft adjuster are rotated relative to one another towards the early position until a central locking device automatically locks the hydraulic camshaft adjuster in a center position.

10 . The method according to claim 9 , wherein the electric machine rotates the crankshaft against a main direction of rotation implemented during operation of the internal combustion engine.

11 . The camshaft adjustment system according to claim 1 , wherein the second actuator is located outside of the hydraulic camshaft adjuster.

Assignees

• Schaeffler Technologies Ag

Inventors

• Scheidig Gerhard

Classifications

• F01L2800/02

  Cold running · CPC title

• F01L2800/01

  Starting · CPC title

• F01L2001/34483

  Phaser return springs · CPC title

• F01L2001/34466

  with multiple locking devices · CPC title

• F01L2001/34426

  Oil control valves · CPC title