Variable camshaft timing mechanism with a lock pin engaged by oil pressure

Patent metadata

Field	Value
Publication number	US-10767518-B2
Application number	US-201815986776-A
Country	US
Kind code	B2
Filing date	May 22, 2018
Priority date	Jun 19, 2013
Publication date	Sep 8, 2020
Grant date	Sep 8, 2020

Abstract

A hydraulically operated camshaft phasing mechanism has two lock pins. One of the lock pins engages at an intermediate position and an end lock pin engages near one of the stops at the end of the phaser range of authority. At least one of the locking pins, preferably the end lock pin, when the vane is at an end stop position, is engaged by oil pressure and spring loaded to release when the oil pressure side of the end lock pin is vented.

First claim

What is claimed is:

1. A variable cam timing mechanism for an internal combustion engine, the variable cam timing mechanism having a housing assembly with an outer circumference for accepting drive force and a rotor assembly for connection to a camshaft, having a plurality of vanes coaxially located within the housing assembly, 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 chamber with an advance wall and a retard chamber with a retard wall opposite the advance wall, a motion of the vane within the at least one chamber acting to shift a relative angular position of the housing assembly and the rotor assembly by fluid from a control valve and by cam torque, the variable cam timing mechanism comprising:
an end lock pin slidably located in one of the rotor assembly or the housing assembly, the end lock pin being movable from an unlocked position in which an end portion of the end lock pin does not engage a recess in the other of the rotor assembly or the housing assembly, to a locked position in which the end portion of the end lock pin engages the recess, locking the relative angular position of the housing assembly and the rotor assembly, wherein the end lock pin is biased by a spring toward the unlocked position; and the locked position of the end lock pin is at an end position when the vane is in an advance end stop position;
the control valve being movable into:
a retard mode in which fluid is routed to the retard chamber and fluid is not routed to the end lock pin, such that the end lock pin is moved to the unlocked position by the spring;
an advance mode in which fluid is routed to the advance chamber, and exhausted from the retard chamber; and
an end stop lock mode in which fluid is routed to the advance chamber and the end lock pin is in the locked position.

2. The variable cam mechanism of claim 1 , wherein the control valve is operated by an ECU such that when the internal combustion engine is stopped in a stop-start mode, the control valve is moved to the end stop lock mode with the end lock pin in the locked position when the vane is in the advance end stop position.

3. The variable cam mechanism of claim 1 , wherein the control valve is movable between the advance mode, the retard mode, and the end stop lock mode by a variable force solenoid.

4. The variable cam mechanism of claim 1 , wherein the end lock pin is in the housing assembly and the recess is in the rotor assembly.

5. The variable cam mechanism of claim 1 , wherein the end lock pin is in the rotor assembly and the recess is in the housing assembly.

6. The variable cam mechanism of claim 1 , further comprising a check valve in a supply line in fluid communication with the end lock pin.

7. The variable cam mechanism of claim 1 , in which the end stop lock mode locks the variable cam timing mechanism at a full advance position when the vane is in the advance end stop position.

Assignees

• Borgwarner Inc

Inventors

• Smith Franklin R
• Brown Daniel

Classifications

• F01L1/34409

  by torque-responsive means · CPC title

• F01L2001/34466

  with multiple locking devices · CPC title

• F01L13/00 Primary

  Modifications of valve-gear to facilitate reversing, braking, starting, changing compression ratio, or other specific operations · CPC title

• F01L1/34 Primary

  characterised by the provision of means for changing the timing of the valves without changing the duration of opening {and without affecting the magnitude of the valve lift} · CPC title

• F02D13/02

  during engine operation · CPC title