Patent Application
20080236535
The present invention derives from the technical area of internal combustion engines; it relates to a rotary valve comprising a conical valve portion with a first port for feeding a fuel to the combustion chamber, respectively for an outlet of an exhaust from the combustion chamber, whereas the first port is located within a superficies surface of the conical valve portion.
Internal combustion engines with rotary valves have been known since 1910 with the conception of the Burt McCollum's engine. There has been influence on this concept from Minerva, Panhard & Levassor and Mercedes producing this combustion engine—patented by Knight—till 1939. Due to sealing problems the concept of the Burt McCollum engine had to be abandoned. Conventional cylinder heads with oscillating valves have the well-known disadvantages of offering restricted performance and discontinuous supply of fuel-mixture. Major drawbacks result from the valves, the ignition and the sealings, that need constant surveillance and maintenance with the involved costs.
The EP1304449B1 reveals a valve drive for a rotary valve of an internal combustion engine; the rotary valve according to this invention has a conical valve portion with flow through channel passing this conical valve portion generally perpendicular to a rotation axis of the rotary valve.
The U.S. Pat. No. 2,245,743 discloses a rotary valve assembly for internal combustion engines with a head of a valve member mounted into rotate about its axis in a coacting conical surface of the head, while its stem is carried by two roller bearings. Major drawbacks result from the valves being exposed with their frontal surface to the combustion chamber and thus being exposed to heavy pressure and thermal loads. Another drawback is to be seen in the conical surface of the valve that serves as passageway and as slide bearing without clearly separating these two functions.
The U.S. Pat. No. 3,362,391 reveals rotary valves for intake and exhaust in an internal two or four stroke combustion engine. A rotary valve of that kind is outwardly inclined and comprises a tapered cone-shaped tube having an enlarged gas induction and/or exhaust portion. Furthermore, the valves have a reduced drive portion and an intermediate port portion. All of these portions are integrally formed of one body with an interior bore. Especially the gas induction and/or exhaust portion is adapted to receive a manifold tube, namely a gas induction tube or a gas exhaust tube. Recapitulating, from this prior art document a rotary valve is known, comprising a conical valve portion with a port for feeding a fuel to the combustion chamber, respectively for an outlet of an exhaust from the combustion chamber, whereas the port is located within a superficies surface of the conical valve portion. Major drawbacks of said prior art valves are seen in the tubular embodiment with an axial flow through channel in the whole valve arrangement for the gas induction, respectively the exhaust. Not only the cone-shaped valve portion is discharge with gas/exhaust, but also the rotary tubular cylindrical end portion fixed to that cone-shaped valve portion is exposed to the gas/exhaust.
A rotary valve is disclosed for two or four stroke internal combustion engines which overcomes the above-mentioned disadvantages while offering advantages for the construction, the tightness against uncontrollable gas losses and the ease of operation.
According to at least one embodiment of the present invention a rotary valve for an internal combustion engine is provided comprising a conical valve portion with a first port for feeding a fuel to the combustion chamber, respectively for an outlet of an exhaust from the combustion chamber, whereas the first port is located within a superficies surface of the conical valve portion and whereas a cylindrical valve portion is arranged at a thick end of the conical valve portion with a second port for the fuel, respectively for the exhaust, which is located within a superficies surface of said cylindrical valve portion.
The valve port in the conical valve portion to a cylinder of the engine is taken apart from a second valve port located in an adjacent cylindrical valve portion. Due to that separation of each of the valve portions, namely the conical valve portion and the cylindrical valve portion, it is easy to seal separately each portion at one port at a superficies surface against cylinder head housing. It has to be emphasized that the two separated valve ports close directly the channels to and from the valve by rotating, whereas the operational dependability is significantly increased comparing to the prior art devices. This means that the requirements regarding tightness and cooling are sufficiently designed for mass production.
In at least one preferred embodiment of the invention a flow channel is arranged between the first port of the rotary valve in the conical valve portion and the second port in the cylindrical valve portion, which flow channel is a slant or curved flow channel that crosses a rotation axis of the rotary valve. Furthermore, the conical valve portion is located adjacent to a combustion chamber, which allows an optimal sealing against the combustion chamber in view of different dilatation of the rotary valve and the enclosing cylinder head housing.
A further advantageous embodiment of the invention provides a first sealing located at a thin end of the conical valve portion and a second sealing located close to a transition zone between the conical valve potion and the cylindrical valve portion, whereas the first port of the conical valve portion is located between the first sealing and the second sealing. Further, a third sealing is located at an end of the cylindrical valve portion that is turned away from the conical valve portion, whereas the second port of the cylindrical valve portion is located between the second sealing and the third sealing. To the best advantage at least one of the first, the second or the third sealing is a lamellar labyrinth sealing.
A further advantageous embodiment shows a low friction coating on the rotary valve, which seals the rotary valve against the cylinder head housing and the combustion chamber; by using a low friction coating like a diamond coating no further sealing is needed.
For the sake of a reduced overall height of the cylinder head housing the rotation axis of each rotary valve is arranged perpendicular to a cylinder axis of a cylinder that is served by said rotary valve. For the ease of operation at least a first and a second rotary valve are arranged in a cylinder head of a cylinder, whereas said rotary valves are preferably mounted parallel to each other with the same alignment.
Further preferred embodiments of the invention show cavities in the conical valve portion, the cylindrical valve portion or the cylinder head.
The herein described embodiments of the invention will be more fully understood from the detailed description below and the accompanying drawings, which should not be considered limiting the invention described in the appended claims:
In
Under the cylinder head 18 a cylinder 12 with a piston 13 and a combustion chamber 2 is shown that is served by the rotary valve. The rotary valve comprises a conical valve portion 1 and a cylindrical valve portion 8 that is arranged at the thick end of the conical valve portion 1. The conical valve portion 1 shows at its superficies surface 3 a first port 6 of the rotary valve and a second port 7 of this rotary valve is located at a superficies surface 5 of the cylindrical valve portion 8. Between these first and second ports 6, 7 a slant or curved flow channel 9 is installed. Due to this slant or curved flow channel through the rotary valve the first and second ports 6, 7 are taken apart to the conical valve portion 1, respectively the cylindrical valve portion 8, whereas the slant or curved flow channel crosses a rotation axis of the rotary valve. This inventive arrangement allows for the first time an easy handling of a rotary valve especially regarding sealing.
A first sealing 11a is located adjacent to a second bearing 14b at a thin end of the conical valve portion 1 of the rotary valve and a second sealing is arranged close to a transition zone between the conical valve portion 1 and the cylindrical valve portion 8. The first port 6 is accordingly located between these first and second sealings 11a, 11b. The second port 7 is framed by the second sealing 11b and a further third sealing 11c that is installed at the thick end of the cylindrical valve portion 8 turned away from the conical valve portion 1.
Adjacent to the conical valve portion 1 a valve drive 15 and a first bearing 14a is installed. Characterizing for embodiments of the invention is further the angle between the rotation axis 10 of the rotary valve and a cylinder axis 19 of the cylinder 12, namely the rotation axis 10 and the cylinder axis 19 are arranged perpendicular to the each other, that means that the rotary valve is not outwardly inclined and the overall height of the new rotary valve assembly is reasonably smaller as known from prior art.
The further embodiment of the invention shown in
In
Further possible embodiments of the invention are covered by the claims and therefore comprised by this present application.
