AN OUTLET VALVE FOR COMBUSTION ENGINES AND A PRODUCTION METHOD THEREFOR

Abstract: An outlet valve for combustion engines with a stem (2), a valve plate (4) with a seat (8) which divides the surface of the plate into a first and a second surface section (10, 12 resp.) which are located on the side of the plate (4) which faces towards and away from the stem (2) respectively. The stem (2) has a longitudinal first passage (6) for the supply of cooling air to the plate (4). In the plate (4) second passages (28) extend which communicate with the first passage (6) and which extend substantially radially outwards to near the seat (8), and which lead into the first surface section (10). A method for production of the valve comprises producing two plate parts (14, 16), and a number of channels (20) in one of the plate parts (14). The channels (20) extend radially from the centre of the plate part (14). In a plate part (14), which comprises the first surface section (10), there are provided a number of second passage sections (24), which lead into this surface section (10). The two plate sections (14, 16) are interconnected, whereby the plate part (16) which does not have the channels (20) closes these, thereby providing a first passage, which is closed in section, and one end of which communicates with the first passage (6), and the other end of which communicates with the second passage sections (24).

Description: AN OUTLET VALVE FOR COMBUSTION ENGINES AND A PRODUCTION METHOD THEREFOR The invention concerns an outlet valve as indicated in the introduction to claim 1. The invention further concerns a method for production of the valve, as indicated in claim 4. 5 In Norwegian patent application no. 963197 a valve of this type is described, wherein there extends through the valve stem and the valve plate a passage which leads into a valve surface section which constantly communicates with the downstream side of the valve. An object of the invention is therefore to provide a valve of the type 0 mentioned in the introduction which is capable of withstanding high temperatures, this being an essential property for achieving a high degree of efficiency in the engine, passages being provided in the valve for through- flow of a cooling fluid. It is a further object of the invention to provide a light valve, the valve weight being a critical parameter for the achievement 5 of high RPM or high piston stroke frequency. A further object of the invention is to provide a method for the production of such a valve. The characteristics of the valve according to the invention are presented in the characteristic features indicated in the claims. The valve will now be described in more detail with reference to the drawing 0 which schematically illustrates embodiments of the valve. Fig. 1 is a side view of a first embodiment of a valve according to the invention, where the right half of the valve is shown as a longitudinal section through it, where a section of the valve has been cut away. Fig. 2 is a section along line II-II through the valve which is illustrated in fig. 5 1. Fig. 3 is a section along line III-III through the valve which is illustrated in fig. 2. Fig. 4 is a side view of a second embodiment of a valve according to the invention where a section of the valve has been cut away. 0 Fig. 5 is a side view of a third embodiment of a valve according to the invention where a section of the valve has been cut away. The same reference numerals are used for corresponding components or sections of the different embodiments of the valve. As illustrated in fig. 1 , the valve comprises a cylindrical stem 2 and a valve plate 4. The valve plate 4 is circular and disk-shaped and extends along a disk plane S which is perpendicular to the stem's longitudinal axis. Through the stem 2 there extends a first passage 6, and a seat 8 is provided in the plate 4 along its periphery. The seat 8 divides the surface of the plate into a first and a second surface section 10 and 12 respectively, which are located on the side of the plate 4 which faces towards and away from the stem 2 respectively. This figure also illustrates how the stem 2 is securely connected to a first, circular and disk-shaped part 14 of the plate 4 and that the first passage 6 extends through this first plate part 14. It is further illustrated that there is provided a second circular, disk-shaped plate part 16 which is inserted in a circular recess 18 in the front of the first valve plate part 14, i.e. in the side of the first plate part 14 which faces away from the stem 2. As illustrated in fig. 2 there are provided in the front of the first plate part 14 and in the recess 18 groove-shaped channels 20 which are defined by protrusions 22 which project away from the stem 2. A first end of the channels is connected to or communicates with the first passage 6. The protrusions 22 and thereby the channels 20 are evenly distributed along a circle with the centre on the stem's longitudinal axis. In the first plate part 14 there are provided a number of holes 24, which are connected to or communicate with a second end of the respective channels 20, and which lead into the first surface section 10. The two plate sections are securely interconnected, e.g. by welding seams which extend at each protrusion 22 and which are indicated by broken lines in fig. 2. A welding seam further extends along the circular edge of the recess 18, thus connecting this edge with the perimeter edge of the second plate part 16. The second plate part 16 thereby closes the channels 20, thereby providing first passage sections 26, which are closed in section and one end of which at the centre of the plate parts communicates with the first passage 6, and the other end of which communicates with the holes 24. Thus, together with the holes, which may instead be called second passage sections 24, the first passage sections 26 form a second passage 28. The welding seams are preferably produced by electronic beam welding, thereby advantageously ensuring that the welding seams extend very close to the contour of each protrusion 22, thus avoiding to the greatest possible extent the formation of fracture points. If a welding seam is also provided along the central section of each protrusion, this ensures that no bulging occurs in the second plate part 16 due to material yield or creep of this part when it is exposed to high temperature. Since the outlet of the holes, e.g., forms the narrowest section of the individual passageways through the valve, by means of an appropriate choice of pressure at the inlet and the outlet of the passageways, viz. at the inlet of the passage 6 in the stem 2 and the outlet of the holes 24, a maximum gas velocity , viz. the velocity of sound, can be achieved. By means of an accurate design of the holes 24, the same amount of cooling air through-flow mass per time unit can thereby be obtained through each channel and a highly homogeneous cooling of the valve. Due to the fact that a high gas velocity is obtained by this means, a substantial cooling effect can be achieved. In order to achieve an accurate design of the holes, use can be made, e.g., of laser devices. Correspondingly, the channels 20 may be formed by electro-erosion. Fig. 4 illustrates a second embodiment of a valve according to the invention. In this case the first and the second plate parts are concave in shape. Fig. 5 illustrates a third embodiment of a valve according to the invention, where the first plate part comprises a section 30 which is securely connected to the valve stem 2, and a plate 32. This plate 32 and the second plate part 16 may initially be produced separated from the stem 2 and the section 30 by pressing, after which they are machined. The channels and a central hole may be produced in the plate 32 by electro-erosion, after which the plate part 16 and the plate 32 are welded together by electronic beam welding. This assembly is then attached to the section 30, also by electronic beam welding. The plate 32 and the plate part 16 hereby extend convexly away from the stem. In the embodiments according to figs. 4 and 5, stresses in the plate during operation of the motor will include membrane stresses, thus loading the valve in an advantageous manner, resulting in a light valve. It was stated above that the channels 20 and the holes 24 are made in the first plate part 14 or the plate 32. It will be understood, however, that, if the second plate part 16 has a different shape, the channels and the holes may be produced in this part instead. In this case the second plate part may, e.g., include the seat and an extended peripheral section in which the holes 24 extend. When tested, the valve has fulfilled all expectations.

Claims: PATENT CLAIMS 1. An outlet valve for combustion engines, comprising - a cylindrical stem section, hereinafter called stem (2), - a circular, substantially disk-shaped plate section, hereinafter called plate (4), which is securely connected to the stem (2) and which extends along a disk plane (S) which is perpendicular to the stem's (2) longitudinal direction, and which has a seat (8) extending along its periphery, which seat divides the surface of the plate into a first and a second surface section (10, 12 resp.), which are located on the side of the plate (4) which faces towards and away from the stem (2) respectively, and the stem (2) comprises a first passage (6) which extends in the stem's longitudinal direction to the plate (4), characterized in that in the plate (4) there extends at least one passage (28) with a first passage section (20) which communicates with the first passage (6) and extends substantially radially outwards to near the seat (8), and a second passage section (24) which leads into the first surface section (10). 2. A valve according to claim 1, characterized in that the plate is convex in the direction away from the stem (2). 3. A valve according to claim 1, characterized in that the plate is concave in the direction away from the stem (2). 4. A method for production of an outlet or inlet valve for combustion engines as indicated in claim 1 , where the valve comprises - a cylindrical stem section, hereinafter called stem (2), - a circular, substantially disk-shaped plate section, hereinafter called plate (4), which is firmly connected to the stem (2) and which extends along a disk plane (S) which is perpendicular to the stem's (2) longitudinal direction, and which has a seat (8) extending along its periphery, which seat divides the surface of the plate into a first and a second surface section (10, 12 resp.), which are located on the side of the plate (4) which faces towards and away from the stem (2) respectively, and the stem (2) comprises a first passage (6) which extends in the stem's longitudinal direction to the plate (4), characterized by the following stages: - to produce the stem (2) and a first circular and disk-shaped part (14) of the plate securely connected thereto and to cause the first passage (6) to extend through the first plate part (14), - to produce a second circular, disk-shaped part (16) of the plate, - to produce in one of the plate parts (14) at least one, open, groove-like channel (20, which extends substantially radially along this plate part's (14) disk plane from near the centre of this plate part (14), - in a plate part (14), which comprises the first surface section (10), to provide at least one second passage section (24) which leads into this surface section (10), - to connect the two plate sections (14,16) sealingly and securely to each other, whereby the plate part ( 16) which does not have the channel (20) closes it, thereby providing a first passage section, which is closed in section and one end of which at the centre of the plate parts (14, 16) communicates with the first passage (6), and the other end of which communicates with the second passage section (24). 5. A method according to claim 4, characterized in that the plate parts (14,16) are interconnected by means of electronic beam welding. 6. A method according to claim 4 or 5, characterized in that the second passage sections (24) are produced by means of a laser.

Inventors: BERGE KNUT, JAKOBSEN LISBETH S, KVAMSDAL ROLF, BERGE, KNUT, JAKOBSEN, LISBETH, S., KVAMSDAL, ROLF
Applicants: BERGE KNUT, JAKOBSEN LISBETH S, KVAERNER ASA, KVAMSDAL ROLF, BERGE, KNUT, JAKOBSEN, LISBETH, S., KVAMSDAL, ROLF
Application year: 1997
Main classification: F01L3
IPC codes: F01L3