Internal-combustion engines – Cooling – With jacketed head and/or cylinder
Patent
1990-03-23
1991-12-24
Kamen, Noah P.
Internal-combustion engines
Cooling
With jacketed head and/or cylinder
184 69, F01P 314
Patent
active
050742566
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The present invention relates to a lubricating system for a valve seat of an internal combustion engine and in particular to a system for lubricating a valve seat of an intake and exhaust valve of an internal combustion engine with which a valve head is in close contact.
BACKGROUND ART
Generally, an intake and exhaust valve mechanism of an internal combustion engine employs a so-called poppet valve. In order to prevent wear in a valve head which is closely located to the wall of combustion chamber, lubricant oil is fed to the valve seat to prevent wear in the valve seat surface.
In addition, in order to feed lubricant oil to the valve seat, the prior art has fed lubricant oil by gravity to the valve seat through a small clearance between the valve stem and the valve guide retaining the stem.
Recently, the internal combustion engine employed a supercharger for boosting the feed pressure of the air-fuel mixture fed to the engine cylinder. The boosted feed pressure of the air-fuel mixture is applied to the clearance between the valve stem of the valve and the valve guide from downstream to upstream of the clearance. Thus, lubricant oil fails to fall through the clearance from upstream to downstream so that the feed of lubricant oil to the valve seat is blocked from sufficiently lubricating the valve seat surface. The head of the valve, when seated on the valve seat surface, receives the internal pressure in the engine cylinder so as to minutely displaced while being in contact with the valve seat surface. In this state, the insufficient feed of lubricant oil to the valve seat surface causes wear in both the head of the valve and the valve seat surface so as to damage the gastightness of the valve, which reduces output of the internal combustion engine.
In view of the above circumstances, an object of the present invention is to provide a lubricating system for a valve seat of an internal combustion engine which ensures lubricant oil is fed to the valve seat so as to prevent wear in the head of the valve and the valve seat surface.
SUMMARY OF THE INVENTION
In accordance with the lubricating system for the valve seat of the present invention, at least a part of the seat ring providing the valve seat surface is made of a porous material readily containing lubricant oil, the outer cylindrical surface of the seat ring is formed with an annular groove, and the engine cylinder head is formed with an oil passage. The lubricant oil which is fed through the oil passage to the annular groove is contained in the porous material part of the seat ring and then produces an oil film on the valve seat surface of the seat ring so as to prevent wear in the valve seat surface and the valve head.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a fragmentary section of the main part of an engine cylinder head, illustrating a lubricating system for a valve seat according to one embodiment of the present invention; and
FIG. 2 is a fragmentary section of the main part of engine cylinder head, illustrating a lubricating system for a valve seat according to a second embodiment of the present invention.
PREFERRED EMBODIMENTS OF THE INVENTION
One embodiment of a lubricating system for a valve seat of the present invention will be described in detail.
FIG. 1 is a fragmentary section of the main part of an engine cylinder head, illustrating the lubricating system for the valve seat according to one embodiment of the present invention.
A cylinder head 1 has a seat ring 2 fitted therewithin and providing the valve seat, i.e., a part of the combustion chamber with which a head 3a of a valve 3 contacts. The outer cylindrical surface of the seat ring 2 is formed with an annular groove 4 along the outer circumference thereof. The annular groove 4 communicates with an oil passage 5 formed in the cylinder head 1.
The seat ring 2 is formed of a single material produced by sintering or a like process which has a mechanical strength sufficient for the valve seat and includes a porous metal structure in part. In particu
REFERENCES:
patent: 3446313 (1969-05-01), Scherenberg
patent: 4147149 (1979-04-01), Andrea
patent: 4169488 (1979-10-01), Goloff
patent: 4200066 (1980-04-01), Berchtold
Kabushiki Kaisha Komatsu Seisakusho
Kamen Noah P.
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