Internal-combustion engines – Poppet valve operating mechanism – Lubrication
Reexamination Certificate
2000-07-17
2001-10-30
Denion, Thomas (Department: 3748)
Internal-combustion engines
Poppet valve operating mechanism
Lubrication
C123S090120, C123S090150, C123S090170, C123S1950HC, C123S19800E
Reexamination Certificate
active
06308673
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to an internal combustion engine having a valve characteristic control mechanism for altering operational characteristic of at least one of a suction valve and an exhaust valve driven by a cam provided on a camshaft, and a control valve for controlling pressure of working oil to be supplied to the valve characteristic control mechanism. Particularly, the present invention relates to an enclosure chamber in the internal combustion engine which encloses an endless flexible member such as chain or belt laid between the camshaft and a crankshaft for transmitting torque of the crankshaft to the camshaft to drive the camshaft.
Hitherto, an internal combustion engine having a valve characteristic control mechanism for altering operational characteristic of at least one of a suction valve and an exhaust valve driven by a cam provided on a camshaft supported on a cylinder head so as to rotate, and a control valve for controlling pressure of working oil to be supplied to the valve characteristic control mechanism has been known (Japanese Laid-Open Patent Publication No. 10-89023).
In this internal combustion engine, the control valve is constituted by an electro-magnetic solenoid valve and attached on a side surface of the cylinder head. Therefore, the control valve liable to be heated by electric current is cooled by the air to prevent excessive temperature rise, and since the control valve is positioned at a place not exposed to oil, an oil-proof control valve is unnecessary.
On the one hand, an internal combustion engine having an enclosure chamber for an endless flexible member such as chain or belt laid between the camshaft and the crankshaft to drive the camshaft by torque of the crankshaft which is formed by a case formed by an engine main body and a cover covering the case has been known.
In the internal combustion engine described in the above-mentioned Japanese publication, the control valve is projected from a side surface of the cylinder head, therefore arrangement of parts in the vicinity is restrained in order to avoid interference with the parts, and there is a room for improvement from a viewpoint of compactness of the engine. Further, the control valve is apt to vibrate owing to vibration transmitted from the cylinder head to exert a bad influence on operational performance of the control valve. Therefore, a control valve which is coped with the vibration and expensive must be used to cause high cost.
On the one hand, in the customary enclosure chamber, the cover vibrates owing to vibration transmitted from the engine main body and noise is generated.
SUMMARY OF THE ENGINE
The present invention has been accomplished in view of the foregoing, and an object of the invention is to make the internal combustion engine having a hydraulic valve characteristic control mechanism compact and restrain vibration of a cover of an enclosure chamber to reduce noise.
Another object of the present invention is to restrain vibration of the control valve owing to vibration of the engine main body, necessitate no expensive control valve coped with vibration, and reduce the cost.
The present invention provides an enclosure chamber for a camshaft driving endless flexible member of an internal combustion engine having a camshaft for driving an engine valve, a hydraulic valve characteristic control mechanism for altering operational characteristic of the engine valve, a control valve for controlling pressure of operating oil supplied to the valve characteristic control mechanism, and the camshaft driving endless flexible member laid between the camshaft and a crankshaft to transmit torque of the crankshaft to the camshaft, wherein the enclosure chamber is formed by a case formed by an engine main body and a cover closing an opening face of the case tightly, the control valve is attached to the engine main body at a portion surrounded by the endless flexible member, the cover has an opening through which the control valve projects outside of the cover, and the case has an attachment section to which a periphery of the opening of the cover is touched tightly and fixed.
According to this invention, since the control valve is attached to the engine main body at a portion surrounded by the endless flexible member utilizing a dead space, the internal combustion engine can be made compact and arrangement of parts in the vicinity is not restrained.
Since the cover is fixed to the attachment section at a position surrounded by the endless flexible member, rigidity of the cover is made high to restrain the vibration and as the result, noise is reduced.
An attachment section to which a mount bracket of the internal combustion engine is fixed may be provided on the engine main body in a neighborhood of he control valve.
Since the mount bracket capable of restraining the engine vibration most is fixed to the vicinity of the control valve, vibration of the control valve is restrained, therefore use of a control valve coped with vibration is unnecessary, and the cost can be reduced.
In the above-mentioned enclosure chamber, the control valve may be attached to a cylinder head constituting a part of the engine main body, the attachment section may be formed on the cylinder head, an end of the cover may touch a seal member of a resilient material fixed to a cylinder head cover constituting a part of the case, and another end of the cover may be fixed to an oil pan constituting a part of the case.
Because an end of the cover is supported from the cylinder head cover by means of the resilient seal member and another end of the cover is fixed to the oil pan, a membranous vibration is generated on the cover. This membranous vibration is apt to be generated most at a portion opposite to the cylinder head. However, the cover is fixed to the attached section at the portion, so that the vibration is restrained efficiently and therefore noise is reduced more.
REFERENCES:
patent: 4508072 (1985-04-01), Takami
patent: 6155218 (2000-12-01), Line
patent: 10089023 (1998-07-01), None
Arent Fox Kintner & Plotkin & Kahn, PLLC
Corrigan Jaime
Denion Thomas
Honda Giken Kogyo Kabushiki Kaisha
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