EP0379715B1 - Light construction gas housing - Google Patents

Abstract

The main parts of the lightweight gas casing are a rigid force-absorbing part (1) consisting of metal plates (2, 3) which can be worked without cutting, have flanges (4, 5, 6) for connecting the casing to fluid-conducting engine parts and are rigidly connected to one another, for example by welding. The channels (12, 16) are sheet metal pressed parts which connect to one another the through-holes (9, 11; 14, 15) in the flanges (4,5, 6), which form the inlet and outlet cross-sections of the fluids, and are welded by their ends to these through-holes.

Description

The present invention relates to a lightweight gas housing with channels for the conduction of gaseous or liquid media and flanges for connecting lines for the supply and discharge of these media into and out of the housing.

Technical field

Housing according to the present invention are preferably components of thermal machines see. FR-A-2 261 420, in which a hot gas is supplied as a working medium and is led out as a relaxed exhaust gas. Such housings have channels for the entering hot gas at high temperature and channels in the immediate vicinity of one another for the exiting, lower temperature cooled exhaust gas after its work. Because of the larger specific volume of the exhaust gas compared to the hot gas, its channel cross section is correspondingly larger. In such a housing there are channels of different cross-sections, which are flowed through by gases of different pressures at different temperatures, which have different thermal expansions in the channel walls, in webs that may be present, in material accumulations that are practically impossible to avoid with cast parts, and also in the mounting flanges. The cast materials used for such housings have relatively low elongations at break, so that there is a risk of expansion cracks as a result of large thermal expansions. If tight flange connections are particularly important, for which, for reasons of cost, no excessive effort can be made, but only the usual thin flat gaskets may be used, then flanges at risk of warpage are not suitable for a secure seal. Gas would escape, the efficiency of the machine would be impaired and the leakage gas could also be hazardous to health.

Object of the invention

The present invention has for its object to avoid the disadvantages shown above as a replacement for the cast version of such gas housings to find a construction in which not only these disadvantages are avoided, but which is also more suitable and more economical for mass production than a cast version. Furthermore, this design should also broaden the range of materials that are suitable for high-temperature gas housings, i.e. that in addition to the relatively few castable high-temperature materials, the much wider range of semi-finished products that can be deformed without cutting, especially in the form of Sheet metal comes into consideration for such gas housings.

Such a construction should also allow, in addition to an expensive material for the high-temperature parts, to use less expensive material for the less heat-stressed parts, which preferably relates to the massive flange parts. The more expensive, highly heat-resistant material also absorbs larger, thermally induced deformations due to its high elongation at break without fear of cracking. Its disadvantage of the higher price is usually at least compensated by the fact that the channel walls can be kept much thinner compared to castings.

For the cheaper materials, which are suitable for the more solid flange sections, the same applies to the elongation at break and deformation behavior as for the materials of the gas-carrying ducts.

However, the material-related advantages of a welded structure composed of thin-walled, shell-shaped pressed parts also result in a disadvantage, namely a reduced stability compared to cast structures. This is of concern if, for example, forces are exerted by the housing on the hot gas-charged apparatus caused by vibrations to be forwarded, for example to the gas supply and discharge lines, which are connected to flanges of the channels mentioned at the beginning for the hot fresh gas and the relaxed exhaust gas. In the long run, the vibrations, supported by the material fatigue, can lead to fractures in the channel walls. The object of the invention is therefore also to keep the destructive influence of vibrations on the thin-walled gas-carrying ducts away by constructive measures. These measures consist of dividing the structure of the housing into a gas-carrying and a force-absorbing part.

Definition of the invention

The lightweight gas housing according to the invention is characterized in that the flanges mentioned are rigidly connected to one another and form a force-absorbing part of the housing, that the channels are formed as pressed sheet metal parts, and that the end cross sections of these channels have openings in at least one of the flanges with openings in at least one other Connect the flanges in a conductive manner, which openings are the inlet and outlet cross sections of the media and on which the ends of the channels are welded to the flanges.

The invention is described in more detail below with reference to an embodiment shown in the drawing.

Brief description of the figures

• Fig. 1 einen Aufriss eines erfindungsgemässen Gasgehäuses, die
• Fig. 2 und 3 das Gasgehäuse in im wesentlichen der Fig. 1 zugeordneten Seitenrissen, aus denen die Führung der Gaskanäle hervorgeht, in etwas nach vorn bzw. nach hinten und seitlich gekippter Stellung, und die
• Fig. 4 eine axonometrische Darstellung des kraftaufnehmenden Teiles der Gehäusestruktur.

In the drawing:

• Fig. 1 is an elevation of a gas housing according to the invention, the
• Fig. 2 and 3, the gas housing in substantially the Fig. 1 associated side tears, from which the guidance of the gas channels emerges, in a little forward or backward and laterally tilted position, and the
• Fig. 4 is an axonometric representation of the force-absorbing part of the housing structure.

Description of the embodiment

The exemplary embodiment shown is the gas housing of a pressure wave charger for internal combustion engines. With two intake ducts, it absorbs the exhaust gases of the engine, which compress the combustion air in a cell rotor and flow into the exhaust system in a relaxed and cooled manner through two exhaust ducts. In the case of a design as a casting, the channels have common boundary walls, the two sides of which are exposed to differently hot gas, with the aforementioned risk of warping of the entire housing due to thermal stresses, which can also result in cracks. Apart from that, the production is by casting due to the complicated routing of the channels complex and also very expensive due to the material, since the entire housing body consists of one and the same, very expensive material, whereas according to the invention a less expensive material is sufficient for the less temperature-stressed parts.

In the figures, 1 means the force-absorbing part of the housing, which consists of two flange plates 2 and 3 made of sheet metal that can be deformed without cutting, each with legs that are perpendicular to one another. The larger legs, which in the figures are vertical and essentially parallel to one another, form flanges 4 and 5, of which one, 4, for connection to the rotor housing and the other, 5, receives the outlet part of an exhaust duct onto the bottom is received, and serves as a connection flange for the exhaust system of the engine.

The two other, shorter legs 6 and 7 of the flange plates 2 and 3 lie one on top of the other in the manner shown in FIGS. 2, 3 and 4 and are connected to one another along their parallel side edges by weld seams 8. The leg 6 has an essentially rectangular opening 9, see FIGS. 3 and 4, while the leg 7 consists of two rod-shaped parts delimiting the opening 9 laterally.

At the opening 9 of the shorter leg 6 of the flange plate 2, the hot exhaust gas coming from the engine enters the housing, as indicated by the flow arrows 10. The short leg 6 thus forms a flange for the connection of an exhaust pipe (not shown) coming from the engine and is therefore described below Called exhaust flange. In the flange 4 there are two diametrically opposed openings 11 through which the hot exhaust gas entering at 9 exits the housing and enters the cell rotor of the pressure wave charger, not shown. The shape of the hot gas channel 12, which connects the opening 9 with the openings 11, can be seen from FIGS. 1, 2 and 3. Starting from the rectangular cross-section at the opening 9, where it is welded on its circumference to the underside of the exhaust flange 6, it widens upwards and branches into two branches, which are welded to the circumference of the openings 11 in the flange 4.

The expanded and cooled gas in the cell rotor, hereinafter called exhaust gas, enters, as the flow arrows 13 indicate, through the two diametrically opposite openings 14 in the flange 4 into the housing and leaves it in the region of a circular opening 15 in the flange 5, from where it continues to flow into an exhaust system, not shown. The associated exhaust duct 16 begins with two branches on the two openings 14 of the flange 4, which merge downstream and merge into a circular connection piece which penetrates the opening 15 in the flange 5 and is connected to it by a weld seam 17.

The hot gas duct 12 and the exhaust duct 16 have no common walls and are therefore independent of one another with regard to the thermal expansions. Because of the greater elongation at break of the metal sheets which can be deformed without cutting than is the case with cast materials, there are cracks as can occur in cast workpieces due to their uneven wall thicknesses. not to be expected in the embodiments according to the invention.

In addition to the two channels 12 and 16 described, other channels could of course be provided between the flanges or other elements of the force-absorbing part if necessary. In the present case, the two small openings 18 shown in FIG. 4 are covered by welded-on elongated sheet metal cups, which delimit so-called "pockets" 19, which are important for a perfect pressure wave process, on the free flange plane facing the rotor of the pressure wave charger, see also FIG. 1 , 2 and 3.

The channels for the hot gas and the exhaust gas, which at first glance appear to be complicated, are nevertheless cheaper to manufacture in series production than castings. The channels consist of deep-drawn, half-shells welded to one another, the dividing lines being provided along their axis of symmetry or along suitable lines of contact of tangential planes or envelope surfaces. If necessary, undercuts must also be mastered in terms of production technology. The welds can be robotized. The weight saving compared to castings is very significant, which means lower costs, which can be reduced even further with a housing with channels that are subjected to different temperatures if the material quality that is sufficient for each channel is selected. Channels with less stress can therefore be pressed from cheaper material. Because of the free, mutually independent deformability of the Channels play different material properties, such as thermal expansion numbers for durability.

This type of housing is of course not only advantageous for thermally stressed machines, but is also an economical alternative to cast designs for other applications, e.g. for liquids and cold gases.

If it is important to keep heat losses from the hot gas channels as low as possible, it is expedient to provide an insulating jacket 20 which is sealed with its edges to the flanges, the contour of which is indicated by dash-dotted lines in FIG. 3 and which encapsulates all or only the hot gas channels to the outside . The latter are thermally insulated even better if the space surrounding the ducts, but especially the hot gas ducts, which is enclosed by the insulating jacket, is conductively connected to the hot gas ducts 12 via a bore 21, see FIG. 3, and is therefore surrounded by hot gas. The insulating jacket also reduces noise emissions from the ducts. An even better noise reduction is obtained by filling the said space with a noise and heat insulating material.

Claims (5)

1. Lightweight gas casing having channels (12, 16) for conducting gaseous or liquid media and having flanges (4, 5, 6) for connecting lines for the feeding and removal of these media into and out of the casing, characterised in that the said flanges (4, 5, 6) are rigidly connected to one another and form a force-absorbing part (1) of the casing, in that the channels (12, 16) are constructed as sheet metal pressed parts, and in that the end cross-sections of these channels (12, 16) conductively connect through-holes (9, 14) in at least one (6, 4) of the flanges to through-holes (11, 15) in at least one (4, 5) of the other flanges, which through-holes are the inlet and outlet cross-sections of the media and at which the ends of the channels (12, 16) are welded to the flanges (4, 5, 6).

2. Lightweight gas casing according to Claim 1, constructed as a gas casing of a pressure-wave supercharger, having one flange (4, 5, 6) each for connecting to the rotor casing of the pressure-wave supercharger, to the exit gas line of an internal combustion engine and to an exhaust line, and having a hot gas channel (12) and an exhaust channel (16) for feeding the exit gas from the engine into the rotor of the pressure-wave supercharger and for removing the expanded and cooled exit gas from the rotor into the exhaust line, characterised in that the flange (4) for connecting to the rotor casing and the flange (6) for connecting to the exit gas line form two limbs, at right angles to one another of a flange plate (2), in that the flange (5) for connecting to the exhaust line forms part of a flange plate (3) which has two rod-shaped limbs (7) at right angles to the flange (5), in that the flange plate (3) is welded along the outer edges of these limbs (7) to two side edges of the exit gas flange (6), and in that the hot gas channel (12) and the exhaust channel (16) are welded together out of two deep-drawn half-shells each and which split, in each case, into two branches starting at a one-piece through-hole (9, 15) in the exit gas flange (6) or exhaust flange (5), which branches end in two through-holes (18, 14) in each case of the rotor casing flange (4).

3. Lightweight gas casing according to Claim 1, characterised by an insulating jacket (20) which encapsulates at least hot gas conducting channels (12) and is secured sealingly by its edges to the flanges (4, 5, 6).

4. Lightweight gas casing according to Claim 3, characterised in that the hot gas conducting channels (12) communicate via a bore (21) with the space enclosed by the insulating jacket (20).

5. Lightweight gas casing according to Claim 3, characterised in that the space limited by the insulating jacket (20), the flanges (4, 5, 6) and the channels (12, 16) is filled with a noise-deadening and heat-insulating material.

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