AU716086B2

AU716086B2 - An outlet valve for combustion engines

Info

Publication number: AU716086B2
Application number: AU36366/97A
Authority: AU
Inventors: Knut Berge; Lisbeth S. Jakobsen; Rolf Kvamsdal
Original assignee: Kvaerner ASA
Current assignee: Kvaerner ASA
Priority date: 1996-07-31
Filing date: 1997-07-31
Publication date: 2000-02-17
Anticipated expiration: 2017-07-31
Also published as: AU3636697A; WO1998004813A1; JP2001504563A; NO972301D0; EP0916016A1; CA2261624A1; NO972301L

Description

P:\WPDOCS\AMD\SPECI\716422.SPE 2/12/99 -1- An outlet valve for combustion engines 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.

In GB 440 206 it is disclosed a poppet valve having a stem 1 with an axial channel or cavity 2.

A circular head 3 having threads along its periphery is screwn into a trumpet neck portion and defines a cavity therein. The head 3 has cooling ribs 10 which extend into the cavity. Channels 8 extend through the neck and opens out into an exhaust manifold. The stem 1 has channels S which extend from a tappet chamber to the passage 2. Exhaust gases draw cooling air from the tappet chamber through the channels 2, 5 and 8.

The cooling ribs define a series of channels having an open cross section, not channels having a closed cross section. The free top portion of the ribs are not connected with the opposite neck *r portion of the valve and do not contribute to a stiffening of this neck portion.

S The valve therefore cannot be made of a very thin material without a risk of being deformed, and the weight of the valve is large. Consequently the mass forces exerted when the engine is running, are correspondingly large. Also the cooling of the valve is not very efficient.

20 The present invention seeks to provide a valve of the type 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 throughflow 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 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 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.

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.

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 2 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 20 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 25 provided a second circular, disk-shaped plate part 16 which is inserted in a S• 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.

4 4o° 4 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 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 20 along the central section of each protrusion, this ensures that no bulging :'.o-occurs in the second plate part 16 due to material yield or creep of this part when it is exposed to high temperature.

oeao o Since the outlet of the holes, forms the narrowest section of the individual passageways through the valve, by-means of an appropriate choice 25 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 i 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 30 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, 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., 20 include the seat and an extended peripheral section in which the holes 24 V,.o extend.

When tested, the valve has fulfilled all expectations.

t o O t o 9= 9..

9* 9 e

Claims

1. An outlet valve for combustion engines, including a cylindrical stem section, hereinafter called stem, a substantially disk-shaped plate section, hereinafter called plate which extends from the stem essentially along a plane perpendicular to the stem, and which has a central portion which is fixedly connected to the stem, and a seat which extends along the periphery of the plate and divides the surface of the plate into a first and a second surface section located on the side of the plate which faces towards and away from the stem respectively, where the first surface and the seat belong to a first part of the plate, the second surface belongs to a second part of the plate, the stem includes a first passage which extends axially in the stem to and through the first part of the plate, one of the parts are provided with a plurality of ribs which extend radially and axially towards the other of the parts and form radial channels which communicate with the 15 first passage and with a plurality of throughgoing, second passage sections formed in the first part in the vicinity of the seat, and the parts are welded together along their periphery, characterised in that the other of the parts is welded to the ribs along these, and that the channels constitute first passage S. sections having a closed cross section.

2. A valve according to claim 1, characterised in that the second surface section of the plate is convex in the direction away from the stem.

3. A valve according to claim 1, characterised in that the second surface section of the plate is concave in the direction away from the stem.

4. A method for production of an outlet or inlet valve for combustion engines as claimed in claim 1, where the valve includes a cylindrical stem section, hereinafter called stem, and a substantially disk-shaped plate section, hereinafter called plate which extends from the stem essentially along a plane P:\WPDOCS\AMD\SPECI\716422.SPE 2/12/99 -6- perpendicular to the stem, and which has a central portion which is fixedly connected to the stem, and a seat which extends along the periphery of the plate and divides the surface of the plate into a first and a second surface section located on the side of the plate which faces towards and away from the stem respectively, where the first surface and the seat belong to a first part of the plate, the second surface belongs to a second part of the plate, the stem includes an first passage which extends axially in the stem to and through the first part of the plate, one of the parts are provided with a plurality of ribs or protrusions which extend radially and towards the other of the parts and form radial channels which communicate with the first passage and with a plurality of throughgoing, second passage sections formed in the first part in the vicinity of the seat, and the parts are welded together along their periphery, characterised by the step by 1welding the other of the parts to the ribs along these by means of electronic beams.

A method according to claim 4, characterised in that each rib is welded to the other of the parts along two radial edge portions of the rib and radially inner and outer edge portions. 20

6. A method according to claim 5, characterised in that each rib is welded to the other of the parts along a radial line between the radial edge portions of the rib.

7. A method according to one of the claims 4 or 5, characterised in that the second passage sections are produced by means of a laser.

8. An outlet valve for combustion engines, substantially as herein described with reference to the accompanying drawings. P:\WPDOCS\AMD\SPEC1\716422.SPE 2/12/99 -7-

9. A method for production of an outlet or inlet valve for combustion, substantially as herein described. Dated this 2nd day of December 1999 KVAERNER ASA By Its Patent Attorneys DAVIES COLLISON CAVE S S S S S S