US3633554A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Valve timing system of automotive internal combustion engine
Assignee: Nissan Motor Co Ltd
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Filing: 1970-07-29
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Granted: 1972-01-11
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Expires: 1990-07-29
Abstract
Abstract A valve timing system for an internal combustion engine of a motor vehicle, including a camshaft which is hydraulically axially movable and which has first and second cam lobes which are positioned and configured relative to the rocker arm for the exhaust valve of the engine cylinder, the first and second cam lobes being selectively aligned with the rocker arm so that the valve is timed in different manners depending upon the driving conditions of the motor vehicle. The hydraulic fluid for axially moving the camshaft is controlled by a solenoid operated discharge valve in response to an engine speed actuated switch and an intake manifold vacuum actuated switch. The valve timing system is adapted for the elimination of air pollution in urban areas without impairing the performance quality of the engine. Such cam lobe configurations may be applied to the cam lobes associated with the intake valve so that not only the exhaust valve but the intake valve can be timed in relation to the driving conditions of the motor vehicle.
Inventors
- 👤 Yasuo Nakajima
- 👤 Yoshimasa Hayashi
- 👤 Kunihiko Sugihara
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 10:28
CPC Classifications
F; F01; F01L; F01L13/00; F01L13/0015; F01L13/0036; F02; F02F; F02F7/00; F02F7/006
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
348 words
In an automotive internal combustion engine having engine cylinders each including intake and exhaust valves, a valve timing system comprising a camshaft rotatable with the crankshaft of said engine and axially movable through a camshaft support bearing fixed relative to the engine cylinder, said camshaft having first and second cam lobes which are located relative to the rocker arm of said exhaust valve, said second cam lobe being greater in size than said first lobe, a cylinder member fixed relative to said engine cylinder and located relative to the leading end of said camshaft, said cylinder member being provided with a stop located for abutting engagement with said leading end of said camshaft, a piston securely mounted on said camshaft at a portion near said leading end and fitted to said cylinder member to define a chamber therebetween, a compression spring seated between said support bearing and said piston for forcing said piston and camshaft toward said stop, a hydraulic fluid supply passage communicating at one end with a source of pressurized hydraulic fluid and at the other with said chamber, a hydraulic fluid discharge passage communicating with said chamber, valve means adapted to selectively open and close said hydraulic fluid discharge passage, and control means for controlling said valve means to normally close said hydraulic fluid discharge passage and to open the discharge passage when said engine is driven at a speed lower than a predetermined level and when the vacuum in the intake manifold of said engine is higher than a predetermined level, said second cam lobe being held in an abutting engagement with said rocker arm when said valve means is in a position to close said hydraulic fluid discharge passage to move said piston and camshaft axially away from said stop against said compression spring and said first cam lobe being moved into abutting engagement with said rocker arm when said valve means is moved to a position to open said hydraulic fluid discharge passage to cause said piston and camshaft to axially move toward said stop by the action of said compression spring.
Claim 2
Dependent Claim
348 words
In an automotive internal combustion engine having engine cylinders each including intake and exhaust valves, a valve timing system comprising a camshaft rotatable with the crankshaft of said engine and axially movable through a camshaft support bearing fixed relative to the engine cylinder, said camshaft having first and second cam lobes which are located relative to the rocker arm of said exhaust valve, said second cam lobe being greater in size than said first lobe, a cylinder member fixed relative to said engine cylinder and located relative to the leading end of said camshaft, said cylinder member being provided with a stop located for abutting engagement with said leading end of said camshaft, a piston securely mounted on said camshaft at a portion near said leading end and fitted to said cylinder member to define a chamber therebetween, a compression spring seated between said support bearing and said piston for forcing said piston and camshaft toward said stop, a hydraulic fluid supply passage communicating at one end with a source of pressurized hydraulic fluid and at the other with said chamber, a hydraulic fluid discharge passage communicating with said chamber, valve means adapted to selectively open and close said hydraulic fluid discharge passage, and control means for controlling said valve means to normally close said hydraulic fluid discharge passage and to open the discharge passage when said engine is driven at a speed lower than a predetermined level and when the vacuum in the intake manifold of said engine is higher than a predetermined level, said second cam lobe being held in an abutting engagement with said rocker arm when said valve means is in a position to close said hydraulic fluid discharge passage to move said piston and camshaft axially away from said stop against said compression spring and said first cam lobe being moved into abutting engagement with said rocker arm when said valve means is moved to a position to open said hydraulic fluid discharge passage to cause said piston and camshaft to axially move toward said stop by the action of said compression spring.
Claim 3
Dependent Claim
134 words
A system according to claim 1, wherein said control means comprises a solenoid valve including a moving core rigidly connected to said valve means, a solenoid coil operatively connected to a source of electric power and a spring means urging said moving core to a position in which said valve means is protruded to close said discharge passage, a first switch interposed between said solenoid coil and said source of electric power and responsive to the revolution speed of said engine, said first switch being closed when said revolution speed is lower than a predetermined level, a second switch connected in series with said first switch and responsive to the vacuum in the intake manifold of said engine, said second switch being closed when the intake manifold vacuum is higher than a predetermined level.
Claim 4
Dependent Claim
153 words
A system according to claim 1, wherein said camshaft has another set of first and second cam lobes which are located relative to the rocker arm of said intake valve and of which the latter is greater in size than the former, the second cam lobe associated with said intake valve being held in an abutting engagement with said rocker arm of said intake valve when said valve means is in a position to close said hydraulic fluid discharge passage to move said piston and camshaft axially away from said stop against said compression spring And the first cam lobe associated with said intake valve being moved into abutting engagement with said rocker arm of said intake valve when said valve means is moved to a position to open said hydraulic fluid discharges passage to cause said piston and camshaft to axially move toward said stop by the action of said compression spring.
Claim 5
Dependent Claim
86 words
A system according to claim 1, wherein said first cam lobe is configured to open said exhaust valve anterior to the bottom dead center of the piston movement in said engine cylinder and to close the same immediately posterior to the top dead center of the engine cylinder piston and said second cam lobe is configured to open said exhaust valve posterior to the bottom dead center of the engine cylinder piston and to close the same substantially at the top dead center of the piston.
Claim 6
Dependent Claim
119 words
A system according to claim 3, wherein said first cam lobe associated with said intake valve is configured to open the intake valve immediately anterior to the top dead center of said engine cylinder piston and to close the same posterior to the bottom dead center of the engine cylinder piston and said second cam lobe associated with said intake valve being configured to open the intake valve substantially at the top dead center of said engine cylinder piston and to close the same posterior to the bottom dead center of the engine cylinder piston substantially later than the timing at which said intake valve is caused to close by said first cam lobe associated with said intake valve.
Claim 7
Dependent Claim
58 words
A system according to claim 4, wherein said first cam lobe is configured to open the exhaust valve at about 50* before the bottom dead center and close the same at about 10* past the top dead center and said second cam lobe is configured to open the exhaust valve at about 50* past the bottom dead center.
Claim 8
Dependent Claim
73 words
A system according to claim 5, wherein said first cam lobe associated with the intake valve is configured to open the intake valve at about 10* before the top dead center and to close the same at about 50* past the bottom dead center and said second cam lobe associated with the intake valve is configured to close the intake valve at an angle appreciably smaller than 50* past the bottom dead center.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-01-10 | 1975-07-12 | 1976-01-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-01-10 | 1979-07-12 | 1980-01-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-01-10 | 1983-07-12 | 1984-01-11 | $7700.00 | Window Closed / Lapsed |