Patent EP0242228A1 successfully refreshed from Google Patents.
EP0242228A1
Expired / Lapsed
EP
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Valve operating mechanism for an internal combustion engine
Assignee: Honda Motor Co Ltd
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Filing: 1987-04-16
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Granted: —
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Expires: 2007-04-16
Abstract
Abstract A valve operating mechanism for an internal combustion engine having a valve (1) disposed in an intake port or an exhaust port of a combustion chamber and being openable by a rotatable cam (3, 4) and cam follower in synchronism with the engine crankshaft rotation. The valve (1) is normally urged toward the closed position by a spring means encircling the valve. Means (11) are provided for varying the resilient force urging the valve (1) toward the closed position during different engine operating conditions, such as, increasing the resilient valve closing force during high-speed operation for ensuring proper valve operation and descreasing the resilient valve closing force during low-speed operation for reducing friction in the valve operating mechanism. The valve operating mechanism preferably includes means for switching between actuation by a low-speed cam (3) or a high-speed cam (4). One form of the spring means includes a mechanism for increasing the spring force on the high-speed cam follower only during high-speed operation. Another form of the spring means includes a valve spring having a non-uniform rate of compression for imposing a higher rate of increase of spring force as the valve is opened a larger amount at high-speed.
Inventors
- 👤 Tadashi C/O Kabushiki Kaisha Honda Hanaoka
- 👤 Kazuo C/O Kabushiki Kaisha Honda Inoue
- 👤 Tsuneo C/O Kabushiki Kaisha Honda Konno
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-30 06:55
CPC Classifications
F; F01; F01L; F01L1/00; F01L1/46; F01L1/462; F01L1/26; F01L1/267
Claims Analysis
Total Claims: 27
Claim 1
Independent Claim
81 words
A valve operating mechanism for an internal combustion engine having a valve disposed in an intake port or an exhaust port of a combustion chamber and being openable by a cam rotatable in synchronism with a crankshaft, said valve operating mechanism comprising spring means for resiliently applying a biasing force which acts in the closing direction of the valve, and means for applying an increased biasing force when the speed of rotation of the engine is higher than a particular value.
Claim 2
Dependent Claim
81 words
A valve operating mechanism for an internal combustion engine having a valve disposed in an intake port or an exhaust port of a combustion chamber and being openable by a cam rotatable in synchronism with a crankshaft, said valve operating mechanism comprising spring means for resiliently applying a biasing force which acts in the closing direction of the valve, and means for applying an increased biasing force when the speed of rotation of the engine is higher than a particular value.
Claim 3
Dependent Claim
60 words
A valve operating mechanism according to claim 1 comprising an auxiliary spring means for applying a biasing force which acts in the same direction as that of the biasing force of said spring means, and means for applying the biasing force of said auxiliary spring means when the speed of rotation of the engine is higher than a particular value.
Claim 4
Dependent Claim
32 words
A valve operating mechanism according to claim 2 including a cam follower engaging said cam, said auxiliary spring means urging said cam follower in a direction to be pressed against said cam.
Claim 5
Dependent Claim
18 words
The valve operating mechanism according to claim 3 wherein said auxiliary spring means comprises a torsion bar spring.
Claim 6
Dependent Claim
29 words
The valve operating mechanism according to claim 3 or 4 wherein said auxiliary spring means includes a pivotally mounted arm which acts directly or indirectly on the cam follower.
Claim 7
Dependent Claim
33 words
The valve operating mechanism according to claim 5, wherein said auxiliary spring means includes a coil spring for continually urging said arm toward engagement with the cam follower with a predetermined low force.
Claim 8
Dependent Claim
47 words
The valve operating mechanism according to claim 6 wherein said pivotable arm comprises a rotatably mounted tube portion with an extending arm portion, and said coil spring engages said tube portion for continually pivoting said pivotable arm toward the cam follower with a relatively small biasing force.
Claim 9
Dependent Claim
61 words
The valve operating mechanism according to claims 4 and 7 wherein said torsion bar spring is mounted in said tube portion, there being means for selectively connecting said torsion bar spring to said tube portion for resiliently resisting pivoting of the pivotable arm by the cam follower and cam during operation of the engine at speeds higher than said particular value.
Claim 10
Dependent Claim
39 words
The valve operating mechanism according to any of claims 5 to 8 including a flange secured to the valve defining a groove, and said pivotal arm having a fork engaging said groove for resiliently resisting opening of the valve.
Claim 11
Dependent Claim
19 words
The valve operating mechanism according to claim 1 comprising a fluid pressurising device for applying said increased biasing force.
Claim 12
Dependent Claim
36 words
A valve operating mechanism according to claim 10 including a first spring directly mounted on said valve, and a second spring separate from said first spring, said fluid pressurising device being associated with said second spring.
Claim 13
Dependent Claim
48 words
A valve operating mechanism according to claim 10, wherein said valve has a head and a stem, and a compression coil spring disposed around said stem, said fluid pressurising device applying a fluid pressure to either one of ends of said spring means for increasing said biasing force.
Claim 14
Dependent Claim
39 words
The valve operating mechanism according to any of claims 10 to 12, wherein the fluid pressurising device includes a piston and cylinder with means for selectively imposing a fluid pressure on said piston to apply said increased biasing force.
Claim 15
Dependent Claim
25 words
The valve operating mechanism according to claim 13, wherein the fluid pressure is by pneumatic pressure which is compressible to allow movement of said piston.
Claim 16
Dependent Claim
37 words
The valve operating mechanism according to claim 13, wherein the fluid pressure is by an incompressible fluid, and a coil spring is arranged to be compressed by increased fluid pressure so as to provide increased biasing force.
Claim 17
Dependent Claim
28 words
The valve operating mechanism according to any of claims 13 to 15 and to claim 12 wherein said piston and cylinder are concentric with and surround the valve.
Claim 18
Dependent Claim
54 words
A valve operating mechanism according to any preceding claim wherein the valve opening timing and said biasing force are both variable in accordance with engine rotational speed, wherein the rotational speed at which the biasing force increases is equal to or greater than the rotational speed at which the valve opening timing is increased.
Claim 19
Dependent Claim
74 words
The valve operating mechanism according to claim 17 wherein the valve operating mechanism includes a low-speed cam and a high-speed cam, a low-speed cam follower engaging and pivoted by the low-speed cam, a high-speed cam follower engaging and pivoted by the high-speed cam, means for selectively operating the valve by the low-speed cam follower for engine speeds below said particular value and by the high-speed cam follower for engine speeds above said particular value.
Claim 20
Dependent Claim
74 words
The valve operating mechanism according to any preceding claim wherein said spring means includes a coil-type valve spring encircling the valve and resiliently urging the valve toward the closed position, and said valve spring has non-linear loading characteristics for causing an increasing rate of change of biasing force applied by the spring as compression thereof increases upon increased opening of the valve which occurs when the engine speed is higher than the particular value.
Claim 21
Dependent Claim
41 words
The valve operating mechanism according to claim 19, wherein said valve spring has coils of a varying pitch with the coils at the ends of the valve spring having a smaller pitch than coils in the center of the valve spring.
Claim 22
Dependent Claim
26 words
The valve operating mechanism according to claim 19, wherein the valve spring is conical with coils of a larger diameter at one end than the other.
Claim 23
Dependent Claim
42 words
The valve operating mechanism according to claim 19, wherein the valve spring is formed of a spring wire having a varying diameter with the coils at one end of a large diameter wire and the wire diameter decreasing toward the other end.
Claim 24
Dependent Claim
111 words
A valve operating mechanism for an internal combustion engine having an intake or exhaust valve operatively coupled to at least one of a plurality of cam followers operable in response to rotation of a camshaft, a valve spring interposed between the intake or exhaust valve and an engine body, and a selective coupling mechanism disposed between the cam followers for selectively connecting the cam followers to each other and disconnecting them from each other, said valve spring having non-linear loading characteristics in which the rate of change of the spring load is incresed as the amount of displacement of the valve spring is increased in a direction to open the valve.
Claim 25
Dependent Claim
111 words
A valve operating mechanism for an internal combustion engine having an intake or exhaust valve operatively coupled to at least one of a plurality of cam followers operable in response to rotation of a camshaft, a valve spring interposed between the intake or exhaust valve and an engine body, and a selective coupling mechanism disposed between the cam followers for selectively connecting the cam followers to each other and disconnecting them from each other, said valve spring having non-linear loading characteristics in which the rate of change of the spring load is incresed as the amount of displacement of the valve spring is increased in a direction to open the valve.
Claim 26
Dependent Claim
22 words
The valve operating mechanism according to claim 23, wherein said valve spring is as claimed in any of claims 19 to 22.
Claim 27
Dependent Claim
14 words
An internal combustion incorporating a valve operating mechanism as claimed in any preceding claim.
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