# US 5,701,857 A · Cylinder valve operating system

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- Number: US 5,701,857 A
- Document ID: US5701857A
- Status: Granted
- Kind: A
- Application number: 08/730,007
- Filed: 1996-10-11
- Granted: 1997-12-30
- Earliest claimed: 1995-10-12
- Assignees: Unisia Jecs Corporation
- Inventors: Seinosuke Hara
- Web page: https://patentgrep.com/patent/US5701857A

## CPC

- F02F 1/242: {Arrangement of spark plugs or injectors}
- F01L 1/267: {with means for varying the timing or the lift of the valves}
- F02F: CYLINDERS, PISTONS OR CASINGS, FOR COMBUSTION ENGINES; ARRANGEMENTS OF SEALINGS IN COMBUSTION ENGINES
- F01L: CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES

## Abstract

A cylinder valve operating system comprises a pivotable rocker arm engaged with at least one cylinder valve, a first free cam follower supported by the rocker arm and driven by a first cam with a cam profile suitable for operation at low engine speeds, a second free cam follower supported by the rocker arm and driven by a second cam with a cam profile suitable for operation at high engine speeds, a first lever for establishing a positive motion connection between the first free cam follower and the rocker arm, a second lever for establishing a positive motion connection between the second free cam follower and the rocker arm, and a hydraulic driver for the first and second levers.

## Claims

### Claim 1

A cylinder valve operating system comprising:
at least one cylinder valve;
a camshaft with at least one set of cams including a first cam and a second cam;
a rocker arm pivotable about a rocker arm axis,
said rocker arm having at least one finger engageable with said at least one cylinder valve for actuating said cylinder valve as said rocker arm pivots about said rocker arm axis;
a first free cam follower supported by said rocker arm for pivotable motion about a first free cam follower axis stationary relative to said rocker arm and driven by said first cam for pivotable motion relative to said rocker arm about said first free cam follower axis;
a first lever supported by said rocker arm for rotatable motion about a first lever axis stationary relative to said rocker arm, said first lever having an engaged position wherein said first lever is in driving engagement with said first free cam follower at a portion radially spaced from said rocker arm axis to provide a positive motion connection between said first free cam follower and said rocker arm as said free cam follower pivots, and a disengaged position wherein said first lever is out of driving engagement with said first free cam follower to provide a lost motion between said first free cam follower and said rocker arm as said first free cam follower pivots;
a second free cam follower supported by said rocker arm for pivotable motion about a second free cam follower axis and driven by said second cam for pivotable motion relative to said rocker arm about said second free cam follower axis;
a second lever supported by said rocker arm for rotatable motion about a second lever axis stationary relative to said rocker arm, said second lever having an engaged position wherein said second lever is in driving engagement with said second free cam follower at a portion radially spaced from said rocker arm axis to provide a positive motion connection between said second free cam follower and said rocker arm as said second free cam follower pivots, and a disengaged position wherein said second lever is out of driving engagement with said second free cam follower to provide a lost motion between said second free cam follower and said rocker arm a said second free cam follower pivots;
a first spring resilietly biasing said first lever toward said engaged position thereof;
a second spring resiliently biasing said second lever toward said disengaged position thereof; and
means for driving saint first lever toward said disengaged position thereof against said first spring and said second lever toward said engaged position thereof against said second spring.

### Claim 2 (depends on 1)

A cylinder valve operating system as claimed in claim 1,
wherein said rocker arm includes a hub formed with a cylindrical bore which receives a rocker arm shaft supporting said rocker arm for pivotable motion about said rocker arm axis;
wherein said rocker arm includes a first wing, a second wing and a third central wing between said first and second wings, said first, third central and second wings being spaced one after another along said rocker arm axis and integrally interconnected by said hub;
wherein said third central wing extends toward said cylinder valve and terminates at a finger for abutting engagement with said at least one cylinder valve;
wherein said rocker arm includes a bearing shaft extending between said first and second wings passing through said third central wing;
wherein said first free cam follower is disposed between said first wing and third central wing and supported by said bearing shaft, and said second free cam follower is disposed between said third central wing and said second wing and supported by said bearing shaft; and
wherein said first lever is rotatably supported by and disposed between the first wing and said third central wing, and said second lever is rotatably supported by and between said third central wing and said second wing.

### Claim 3 (depends on 1)

A cylinder valve operating system as claimed in claim 1, wherein said driving means is in the form of hydraulic means.

### Claim 4 (depends on 1)

A cylinder valve operating system as claimed in claim 1, wherein said second cam has a cam profile suitable for operation at high engine speeds.

### Claim 5 (depends on 3)

A cylinder valve operating system as claimed in claim 3, wherein said second cam has a cam profile suitable for operation at high engine speeds.

### Claim 6 (depends on 5)

A cylinder valve operating system as claimed in claim 5, wherein said first cam has a cam profile suitable for operation at low engine speeds.

### Claim 7 (depends on 1)

A cylinder valve operating system as claimed in claim 1, wherein said first lever a axis and said second lever axis are aligned with each other.

### Claim 8 (depends on 3)

A cylinder valve operating system as claimed in claim 3, wherein said first lever axis and said second lever axis are aligned with each other.

### Claim 9 (depends on 4)

A cylinder valve operating system as claimed in claim 4, wherein said first lever axis and said second lever axis are al aligned with each other.

### Claim 10 (depends on 7)

A cylinder valve operating system as claimed in claim 7, wherein said first and second levers are identical in construction.

### Claim 11 (depends on 8)

A cylinder valve operating system as claimed in claim 8, wherein said first and second levers are identical in construction.

### Claim 12 (depends on 9)

A cylinder valve operating system am claimed in claim 9, wherein said first and second levers are identical in construction.

### Claim 13 (depends on 3)

A cylinder valve operating system as claimed in claim 3, wherein said hydraulic means include a first hydraulic piston slidably received in a first bore of said rocker arm adjacent said first lever, a second hydraulic piston slidably received in a second bore of said rocker a cm adjacent said second lever, a source of hydraulic fluid pressure, a first hydraulic fluid circuit fluidly disposed between said source of hydraulic fluid pressure and said first bore, and a second hydraulic fluid circuit fluidly disposed between said source of hydraulic fluid pressure and said second bore.

### Claim 14 (depends on 13)

A cylinder valve operating system as claimed in claim 13, wherein said first hydraulic circuit includes a first solenoid operable valve having a discharge position wherein hydraulic fluid is discharged from said first bore and a supply position wherein hydraulic fluid is supplied from said source of hydraulic fluid pressure to said first bore.

### Claim 15 (depends on 14)

A cylinder valve operating system as claimed in claim 14, wherein said second hydraulic circuit includes a second solenoid operable valve having a discharge position wherein hydraulic fluid is discharged from said second bore and a supply position wherein hydraulic fluid is supplied from said source of hydraulic fluid pressure to said second bore.

### Claim 16 (depends on 15)

A cylinder valve operating system as claimed in claim 15, wherein said first cam has a cam profile suitable for operation at low engine speeds, and said second cam has a cam profile suitable for operation a high engine speeds.

### Claim 17 (depends on 15)

A cylinder valve operating system as claimed in claim 15, wherein, when said first solenoid operable valve assumes said discharge position thereof and said second solenoid operable valve assumes said discharge position thereof, said first free cam follower and said rocker arm are engaged to be driven by said first cam.

### Claim 18 (depends on 17)

a cylinder valve operating system as claimed in claim 17, wherein, when said first solenoid operable valve assumes said supply position thereof and said second solenoid operable valve assumes said supply position thereof, said second free cam follower and said rocker arm are engaged to be driven by said second cam.

### Claim 19 (depends on 18)

A cylinder valve operating system as claimed in claim 18, wherein, when said first solenoid operable valve assumes said supply position thereof and said second solenoid operable valve assumes said discharge position thereof, both said first and second free cam followers are disengaged from said rocker arm, leaving said rocker arm at rest.

### Claim 20 (depends on 19)

A cylinder valve operating system as claimed in claim 19, including a rocker arm shaft supporting said rocker arm.

### Claim 21 (depends on 20)

A cylinder valve operating system as claimed in claim 20, wherein said rocker arm shaft is formed with a first axial passage and a second axial passage forming parts of said first and second hydraulic fluid circuits, respectively.

### Claim 22

A cylinder valve operating system comprising:
at least one cylinder valve;
a camshaft with a cam;
a rocker arm pivotable about a rocker arm axis,
said rocker arm having at least one finger engageable with said at least one cylinder valve for actuating said cylinder valve as said rocker arm pivots about said rocker arm axis;
a free cam follower supported by said rocker arm for pivotable motion about a free cam follower axis stationary relative to said rocker arm and driven by said cam for pivotable motion relative to said rocker arm about said free cam follower axis;
a lever supported by said rocker arm for rotatable motion about a first lever axis fixed to said rocker arm, said lever having an engaged position wherein said lever is in driving engagement with said free cam follower at a portion radially spaced from said rocker arm axis to provide a positive motion connection between said free cam follower and said rocker arm as said free follower pivots and a disengaged position wherein said lever is out of driving engagement with said free cam follower to provide a lost motion between said free cam follower and said rocker arm as said free cam follower pivots;
a spring resilietly biasing said lever toward said engaged position thereof; and
means for driving said lever toward said disengaged position thereof against said spring.