# US 10,767,518 B2 · Variable camshaft timing mechanism with a lock pin engaged by oil pressure

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- Number: US 10,767,518 B2
- Document ID: US10767518B2
- Status: Granted
- Kind: B2
- Application number: 15/986,776
- Filed: 2018-05-22
- Published: 2018-09-20
- Granted: 2020-09-08
- Earliest claimed: 2013-06-19
- Assignees: BorgWarner Inc.
- Applicants: BorgWarner Inc.
- Inventors: Franklin R. Smith; Daniel Brown
- Web page: https://patentgrep.com/patent/US10767518B2

## CPC

- F01L 1/34: 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}
- F01L 1/047: Camshafts
- F01L 1/34409: {by torque-responsive means}
- F01L 1/3442: {using hydraulic chambers with variable volume to transmit the rotating force}
- F01L 13/00: Modifications of valve-gear to facilitate reversing, braking, starting, changing compression ratio, or other specific operations
- F01L 31/00: Valve drive, valve adjustment during operation, or other valve control, not provided for in groups F01L15/00 - F01L29/00 (sensing elements measuring the variable or condition to be controlled or regulated F01B25/04)
- F01L 2001/34423: {Details relating to the hydraulic feeding circuit}
- F01L 2001/34446: {Fluid accumulators for the feeding circuit}
- F01L 2001/34459: {Locking in multiple positions}
- F01L 2001/34463: {Locking position intermediate between most retarded and most advanced positions}
- F01L 2001/34466: {with multiple locking devices}
- F01L 2001/34469: {Lock movement parallel to camshaft axis}
- F02D 13/02: during engine operation
- F01L: CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
- F02D: CONTROLLING COMBUSTION ENGINES (vehicle fittings, acting on a single sub-unit only, for automatically controlling vehicle speed B60K31/00; conjoint control of vehicle sub-units of different type or different function, road vehicle drive control systems for purposes other than the control of a single sub-unit B60W)

## 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.

## Claims

### Claim 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.

### Claim 2 (depends on 1)

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.

### Claim 3 (depends on 1)

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.

### Claim 4 (depends on 1)

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.

### Claim 5 (depends on 1)

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.

### Claim 6 (depends on 1)

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

### Claim 7 (depends on 1)

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.