This invention relates to a cylinder head of an internal-combustion engine equipped with a lift valve whose annular plate has sealing surfaces on its inner and outer peripheries. The valve when closed position sits with these inner and outer seat surfaces onto inner and outer valve surfaces in the cylinder head.
Many embodiments of a cylinder head with a ring-shaped valve or valves has been proposed. Most of them deal with the principle of cylinder charge exchange with a four-stroke or two-stroke cycle with use of the ring-shaped valve. They do not usually deal with construction details of valve sealing. In some cases the seal surfaces of the inner and outer valve seats are on one planar or conical surface in order to be able to easily precisely machine these surfaces in one operation and ensure sufficient tightness of the ring-shaped valve. These solutions are described e.g. in U.S. Pat. No. 2,222,730, U.S. Pat. No. 2,222,731, DE 3438847 A1, or U.S. Pat. No. 5,673,656. Tightness of the ring-shaped valve in both valve seats is however a problem not only from the point of view of precise machining of valve seats and valves, but even with respect to thermal and mechanical deformations. This could be deformations of the cylinder head, of both of the valve seats, and finally of the ring-shaped valve. A further problem for tightness of the ring-shaped valve is unequal wear of seat faces of the outer and inner seat and valve. The question is the design of seats and cylinder head with respect to their installation into the cylinder head, adjustment and repairs.
The above deficiencies are to a considerable extent removed in an internal-combustion engine with a ring-shaped valve comprising a body and a rigid center of the cylinder head and where the ring-shaped valve is formed with an outer seat face and an inner seat face and that in a closed position sits down into the outer valve seat with the outer seat face and into the inner valve seat with the inner seat face according to this solution. Its substance is that the inner valve seat and/or the outer valve seat is mounted so as to be axially slidable relative to at least one biasing member that applies a force against the ring-shaped valve.
The slidably movable inner valve seat and/or the outer is valve seat is provided with at least one seal member between the inner valve seat and the center of the combustion engine cylinder head and/or between the outer valve seat and the body of the combustion-engine cylinder head.
The seal member is set in a groove in the center of the cylinder head of the combustion engine and/or in the cylinder head body of the combustion engine. The seal member is formed by the seal ring on the slideably moveable inner valve seat the contact diameter of seal member with the inner valve seat being larger than the seat face diameter of this inner valve seat in engagement with the ring-shaped valve.
The seal member is formed by the seal ring on the slideably moveable outer valve seat, the contact diameter of seal ring with the outer valve seat being smaller than the seat face diameter of this outer valve seat in engagement with the ring-shaped valve.
The slidably movable inner valve seat and/or the outer valve seat is provided with a safety element preventing its pulling toward the cylinder. The slidably movable inner valve seat and/or the outer valve seat is provided with at least two stems extending through the center and/or through the body of the cylinder head of the combustion engine and provided with adjustable stops and/or dampers on their ends.
The seat face of the slidably movable inner valve seat and/or the outer valve seat is part-spherical.
The biasing member is formed by a hydraulic spring with a throttle in the oil supply and/or one-way throttle in the oil supply.
The center of the combustion engine cylinder head is demountable from the body of the combustion engine cylinder head and/or valve guide for guiding the valve stems of the ring-shaped valve fitted with radial clearance in the center and/or in the body of the combustion engine cylinder head.
The cylinder head of the combustion engine with the ring-shaped valve achieves flow parameters not achievable by any solution with classic lift valves. It is thus possible to use it in new modern internal-combustion engines. Thanks to the concentric circular shape of the valve seats and valve plate with the cylinder of the engine there is thermally uniform stress of all parts of the cylinder head. In this arrangement where the outer valve seat is fixed and the inner valve seat is axially movable the center of the cylinder head is less stressed than usual. Most of pressure force urges the valve into the outer valve seat. Thanks to lower stress and simple shape there is no danger of the cylinder head cracking even at high combustion pressure and temperature. The inner valve seat must have a certain axial overlap T in order to ensure valve tightness. The size of this overlap is given by the stop position of seat movement toward the cylinder defined by e.g. the safety ring. During installation is possible to set the desired lift of the movable seat needed for safety and durable sealing of the ring-shaped valve in the closed position. Wear of seat face stops increase lift of slidably mounted seat. Wear of the seat face for valve by this slidably mounted seat decreases the adjusted overlap of the slidably mounted seat. Wear of the seat face between the second fixed seat and the valve increases overlap of the movable seat. It is advantageous that two wear factors increase the adjusted overlap and one factor decreases it. It follows that for sufficient sealing the overlap is permanent for a long period and will not need to be adjusted.
The cylinder head of the combustion engine with a ring-shaped valve according to the invention will be described in more detail by individual examples shown on the attached drawings.
The model cylinder head of a combustion engine with the ring-shaped valve according to
The cylinder head of an internal-combustion engine with the ring-shaped valve 3 according to
The cylinder head of an internal-combustion engine with the ring-shaped valve 3 according to
In the cylinder head of an internal-combustion engine with the ring-shaped valve 3 according to
In the cylinder head of an internal-combustion engine with the ring-shaped valve 3 according to
In the cylinder head of an internal-combustion engine with the ring-shaped valve 3 according to
In the cylinder head of an internal-combustion engine with the ring-shaped valve 3 according to
In the embodiment of a cylinder head of an internal-combustion engine with the ring-shaped valve 3 according to
In the embodiment of a cylinder head of an internal-combustion engine with the ring-shaped valve 3 according to
The cylinder head of an internal-combustion engine with the ring-shaped valve 3 functions as follows. The ring-shaped valve 3 by closing sits down at first on the axially slidably mounted, usually inner valve seat 4, presses this inner valve seat 4 against the resistance of the biasing member 6 and then sits down into the rigid, usually outer valve seat 5. The seat face 10 of the inner valve seat 4 may be advantageously part-spherical and then is secured perfect tightness of this inner valve seat 4 in the seat face 20 of the ring-shaped valve 3 even in case of modest turning of the inner valve seat 4. This seat face 20 may be conical or part-spherical as well. An increase of pressure in a cylinder of the engine pushes the axial slidably mounted inner valve seat 4 to the ring-shaped valve 3 by the pressure force F. This is caused by suitable shape of the inner valve seat 4, where the diameter D1 of contact with seal member ring 7 is greater than the diameter D2 of contact of the seat faces 10 and 20. Tightness between the center 2 of the head and the axially slidably mounted inner valve seat 4 secures the seal member ring 7 that is advantageously set in a groove in the center 2 of the head. The next step of the cylinder head of an internal-combustion engine causes opening the ring-shaped valve 3. If there is higher pressure in the cylinder before opening than pressure above the ring-shaped valve 3, the axially slidably mounted inner valve seat 4 will be able to be pushed to the ring-shaped valve 3 by pressure force F even during opening of the valve 3 in addition to force of the biasing member 6. It will be thus pulled toward the cylinder until movement of the seat is stopped by the safety member 8. This cyclical motion of the inner seat 4 will remove sediment from the space between the inner valve seat 4 and the center 2 of the head. This requires that the radial clearance between the inner valve seat 4 and the center 2 of the head be sufficient to prevent sticking of the inner valve seat 4. The inner valve seat 4 is after opening valve 3 ready in its extended position. Required overlap T, which is necessary for keeping tightness of the ring-shaped valve 3 while the engine is running, is influenced by wear of the valve gear component. This overlap T is decreased by wear of the seat faces 10 and 20. Wear of the seat faces 11 and 21 is increased and wear of the safety member 8 is increased too. Keeping the overlap T seems to be sustainable. When using a hydraulic cylinder as the biasing member 6 it is possible to absorb movement of the inner valve seat 4 by the throttle 19 in both directions or by the one-way damping 18 in the oil supply. Similar function of a cylinder head with the ring-shaped valve 3 is even present when using the inner valve seat 4 with stems 14 whose ends are provided with biasing members 6 and stops 23 substituting for the safety member 8. The hydraulic damper 24 decreases lift of the inner valve seat 4 and thus its wear too while the engine is running.
Similar function of a head will be obtained even when the axially slidable element is the outer valve seat 5. In the closed position of the ring-shaped valve 3 pressure force F will bias the axially slidable outer valve seat 5 toward the ring-shaped valve 3 only when the diameter D1 of contact with the seal ring 7 is smaller than the diameter D2 of contact of the seat faces 11 and 21.
The biasing member 6 can be a spring of various types. Also it may be a hydraulic or pneumatic cylinder, electromagnet and the like.
The safety member 8 can be a thrust nut 12 or plate 13 fixed in the center 2 of the head. The safety member can be an annulus 17 or it can be generally formed by stops from bolts, pins and the like.
For assembling and adjustment of the inner valve seat 4 it is advantageous when the center 2 of the head can be disassembled. For assembling of the ring-shaped valve 3 it is advantageous when the valve guides 26 are fitted with radial clearance. Their position can be secured according to the position of the ring-shaped valve 3 and its stems 25.
A head of an internal-combustion engine with the ring-shaped valve according to this invention will find use in various types of internal-combustion engines for controlling intake, exhaust or common function of intake and exhaust. Use is advantageous for example for exhaust of a two-stroke engine or of a four-stroke engine common for both exhaust and intake.
Number | Date | Country | Kind |
---|---|---|---|
2011-259 | May 2011 | CZ | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
---|---|---|---|---|
PCT/CZ2012/000037 | 5/3/2012 | WO | 00 | 12/5/2013 |
Publishing Document | Publishing Date | Country | Kind |
---|---|---|---|
WO2012/149915 | 11/8/2012 | WO | A |
Number | Name | Date | Kind |
---|---|---|---|
2222730 | Wallgren | Nov 1940 | A |
4503817 | Klomp et al. | Mar 1985 | A |
5555859 | Melchior et al. | Sep 1996 | A |
5673656 | Knob | Oct 1997 | A |
5782215 | Engelmann | Jul 1998 | A |
5803042 | Bortone | Sep 1998 | A |
20040031454 | Hirano | Feb 2004 | A1 |
Number | Date | Country | |
---|---|---|---|
20140083389 A1 | Mar 2014 | US |