Internal-combustion engines – Valve – Rotary
Patent
1995-05-05
1996-04-23
Okonsky, David A.
Internal-combustion engines
Valve
Rotary
1231908, F01L 700
Patent
active
055093868
DESCRIPTION:
BRIEF SUMMARY
The present invention relates to an oil sealing means, a gas sealing means, and a decompression means to allow correct operation of the gas sealing means for use in rotary valves of internal combustion engines.
The invention provides a means for sealing lubricant present in bearing areas and, in some cases, lubricant present for cooling purposes from the combustion chamber of a rotary valve internal combustion engine and a means for sealing the axial outflow of gases from the combustion chamber. It is applicable to internal combustion engines of both the two or four stroke varieties. It is relevant to any rotary valve assembly in which the rotary valve is configured so that a central working portion rotates in a housing and is supported on bearings that maintain a small running clearance between the rotary valve and its housing.
The present invention consists in a rotary valve of an internal combustion engine having a cylindrical valve, bearing means at each end of said valve supporting said valve for rotation in abore of the cylinder head of the engine with a small radial clearance between the valve and the bore and means of communication between the combustion chamber and the small radial clearance, oil for lubrication of said bearing means, oil sealing means axially inboard of said bearing means arranged to prevent the axial inward leakage of said oil through the small radial clearance to the combustion chamber, a space between said bearing means and said oil sealing means containing oil, and gas sealing means axially inboard of said oil sealing means arranged to minimise outward axial leakage of gas from the combustion chamber through the small radial clearance, characterised in that each gas sealing means consists of at least one circumferential sealing element of the piston ring type housed in at least one circumferentially extending groove formed either in the periphery of the valve or in the bore of the cylinder head and radially preloaded against the surface of the other, each oil sealing means consisting of a non-rotating annular member also having a small radial clearance to the bore of the cylinder head, second sealing means sealing the small radial clearance between the annular member and the bore, an annular cavity lying peripherally in the small radial clearance and extending between the circumferential sealing element and the second sealing means, the annular member having a substantially radially disposed face arranged to seal slidingly against a radially disposed face on the valve, spring means acting on one end of the annular member to urge the radial face of the annular member against the radially disposed face on the valve.
A preferred form of the present invention also provides a decompression means consisting of means preloading said spring means so that pressure build up in said annular cavity due to flow of high pressure gas from the combustion chamber at the start of the compression stroke can unseat said annular member allowing high pressure gas in said annular cavity to exhaust into said space, said exhausting of high pressure gas causing a collapse of pressure in said annular cavity creating a substantial pressure drop across said circumferential sealing element forcing said sealing element to seat sealingly against the axially outer radial face of said groove.
Another preferred form of the present invention also provides a venting means acting to minimize pressure build up in said annular cavity later in the compression and power strokes, said venting means having sufficient resistance to flow of gas from said annular cavity to ensure maintenance of an average positive pressure gradient between said annular cavity and said space during every engine cycle.
In order that the nature of the invention may be better understood an embodiment thereof is hereinafter described, by way of example, with reference to accompanying drawings in which:
FIG. 1 is a longitudinal cross-sectional view of an embodiment of a rotary valve assembly according to the present invention, positioned in the
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patent: 4404934 (1983-09-01), Asaka et al.
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patent: 5074265 (1991-12-01), Ristin et al.
patent: 5152259 (1992-10-01), Bell
patent: 5154147 (1992-10-01), Muroki
Thomas Andrew D.
Wallis Anthony B.
A. E. Bishop Research Pty. Limited
Okonsky David A.
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