JPS6050967B2 - Bent pipe of 4-cylinder parallel engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention comprises conduits formed by thin-walled semi-curved plates and welded together at a common abutting surface to conduct exhaust gases between the cylinder block and the exhaust pipe. This invention relates to bent pipes for internal combustion engines.

Conventional internal combustion engines have bent tubes constructed as castings, which have a large wall thickness and are therefore very heavy.

This kind of bent pipe made of cast steel has sufficient heat resistance,
It also works to damp solid vibrations. In the past, bent pipes made from welded copper pipes could not be used due to their high production costs.

A particular disadvantage of this bent pipe is that it promotes the propagation of propagating sound. In the known bent tube (DE 1576 357), a T-shaped member formed by two half-curved plates is connected to each cylinder outlet, which element connects the inlet bent tube and and diagonal tube pieces.

A plurality of tube sections are laterally connected to one another on the flanges. During operation, there is a risk that the tube piece will bend and the flange joint will lose its tightness. Therefore, the object of the present invention is to not only have permanent durability against high thermal loads, but also to
The object of the present invention is to provide a bent pipe with a lightweight structure that has a damping effect on solid propagation and the spread of sound.

In order to solve this problem, in the curved pipe of the present invention, the entire curved pipe is composed of two half-curved plates, and within the range forming the conduit in the half-curved plates, one or A plurality of flat web edges are abutted and welded, and each semi-curved plate is formed by two deformed thin copper plates, at least the inner thin steel plate! It is made of scale-resistant steel, and a thin insulating layer of compressible heat-resistant material is interposed between the two thin copper plates in the area where the half-curved plate forms a conduit.

Multi-curved plate structures of this kind are sometimes used in silencer production 4 (West German Patent Specification No. 526 321),
Unlike ordinary bent pipes, no special measures are required to cope with high thermal loads.

Since the entire bent tube is constructed by two half-curved plates welded together at the edges and in the area of the web,
The result is a material with unique temperature stability and bending strength in all directions.

The semi-curved plate is made by forming the thin steel plate together with an insulating layer into a drawing.
It is easy to manufacture because it is formed by stamping or pressing. The degree of solid-borne sound attenuation achieved is so good that it is not affected in any way by the absence of an insulating layer in the area of the web.

Since the spread of the insulating layer is limited to the area forming the conduit in the semi-curved plate, the insulating layer can be formed by punching a mineral fiber mat.

The abutting flat adjacent webs extend within the conduit and the webs. The half-curved plate is welded in the range of . According to the invention, the use of insulating materials can be saved. Further, since only the inner thin steel plate of each half-curved plate is made of alloy steel, and the outer thin steel plate is made of inexpensive non-alloy steel, manufacturing costs can be reduced. In a preferred construction, the half-curved plate is provided with at least two bends which are respectively connected to the exhaust gas holes of the two cylinders.

In the case of a 4-cylinder parallel engine, if the ignition order is 1, 3, 4, 2 or 1, 2, 4, 3, the 1st and 4th cylinders are separated by a large external vent for output balance. Preferably, the second and third cylinders are connected to each other via a small inner vent surrounded by a larger vent.

This type of construction is also a very space-saving construction, since the dimension perpendicular to the plane of the vent is only slightly larger than the diameter of the vent.

Depending on the design requirements, the curvature of the bend may be approximately semicircular, or it may deviate significantly from this, for example asymmetrically. In the present invention, if a branch pipe is further provided in the bend, it can be suitably used for a five-cylinder parallel engine. In the area of the half-curved plate, a connecting tube is connected to each bend, and the free end of each tube is connected to an exhaust pipe connection flange, so that thermal stresses can advantageously be limited. This short connecting tube absorbs thermal expansion by changing its shape. DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to drawings showing bent pipes for a four-cylinder parallel engine.

As shown in the plan view of FIG. 1, the bent tube constituted by two half-curved plates includes an outer tube 1 and an inner tube 2, with the outer bend 1 surrounding the inner bend 2.

Each bend 1, 2 is provided with a flange 3 at its free end, and each flange 3 is hermetically screwed onto the outer surface of the cylinder head of a four-cylinder parallel engine (not shown) above the exhaust gas hole of the cylinder. ing. As shown in the cross section 1 (FIG. 1) rotated around the plane of the drawing, the semi-curved plates 5 and 6 of the inner and outer bends for guiding the gas are provided with wide recessed grooves 4 to improve stability.

Both semi-curved plates 5, 6 (see FIG. 2) are arranged at their abutting surfaces 7 along their peripheries, that is, 8 on the outside and 9 on the inside.
, the inner and outer bends are welded to each other at 10, and further welded to each other along the edges 11 and 12 of the web 13 provided between the outer and outer bends. Additional welding may be applied to the inside surface of the web 13. Outer bend 1 and inner bend 2
are connected to the exhaust pipe 21 via the connecting short pipes 14 and 15, respectively.
, 22 (FIG. 3), and the exhaust pipe is connected to both short pipes 14
, 15 is connected to a flange 16 common to the two.

As shown in the sectional view in FIG. 2, a bolt 17 as an additional fastening element is screwed through a hole 18 in the web 13 and a hole 19 in the flange 16 into a flange 20 shown in dashed lines on the exhaust pipe. . As shown in FIG. 1, in order to attach the bent pipe to the web 13 without vibration,
Two bolt holes 18 are provided.

The side view of FIG. 3 shows two exhaust pipes 21 and 22 fixed to the flange 16 on the lower surface of the bent pipe through a common flange 20 by bolt joints (not shown).

The cross-sectional view of FIG. 4 shows that the semi-curved plates each include an outer thin steel plate 23, preferably heat-resistant, with a thickness of about 1.5 Tr$L, and an inner, preferably scale-resistant, thin steel plate 23 with a thickness of about 0.5 Tr$L. It is clearly shown that it is composed of a thin steel plate 24.

An insulating layer 25 made of ceramic fibers based on aluminum silicate, for example, is interposed between the two thin plates except for the peripheral weld 8, and when forming the thin steel plate, this insulating layer 25 is approximately 6mm thick. From 277277! compressed into

[Brief explanation of drawings]

FIG. 1 is a plan view of one embodiment of the bent pipe of the present invention, FIG. 2 is a partially longitudinal front view taken from the line ■-■ in FIG. 1, and FIG. - Figure 4 is a side view seen from line 3.
An enlarged sectional view of a portion corresponding to ■ in the figure is shown. 1...Outer bend, 2...Inner bend, 3...Flange, 4...Concave groove, 5, 6...Semi-curved plate, 7...
Abutment surface, 8, 9, 10... Welding (part), 11, 12
...edge, 13...web, 14,15...short tube,
16...flange, 17...bolt, 18,19.
... Hole, 20 ... Flange, 21, 22 ... Exhaust pipe, 23, 24 ... Thin steel plate, 25 ... Insulating thin layer.

Claims (1)

[Scope of Claims] 1. Consisting of two thin half-curved plates 5, 6, each half-curved plate 5, 6 is formed by two deformed thin steel plates 23, 24, and at least the inner side thereof The thin steel plate 24 is made of scale-resistant steel, and in the range where the half-curved plates 5 and 6 between the two thin steel plates 23 and 24 form a conduit, an insulating thin layer 25 made of a compressible heat-resistant material is interposed. In the bent pipe of a four-cylinder parallel engine for guiding exhaust gas between the cylinder block and the exhaust pipe, both half-curved plates 5 and 6
However, in the area where it forms a conduit, the edges of one or more flat webs 13 are brought into contact with the abutting surface 7 and are welded to each other, and each half-curved plate 5, 6 each includes at least two bends 1 and 2 connected to the exhaust gas holes of two cylinders, and the first cylinder and the fourth
An outer bend 1 that connects the cylinders concentrically surrounds an inner bend 2 that connects the second cylinder and the third cylinder, and the connecting short pipes 14 and 15 of both bends 1 and 2 have a common flange 16. A bent pipe for a 4-cylinder parallel engine. 2 In the area of the half-curved plate, connect 1 short pipe to each bend.
4, 15 are provided, and the free end of each short pipe is connected to the exhaust pipe 21, 22.
The bent pipe for a four-cylinder parallel engine according to claim 1, wherein the bent pipe is connected to a flange 16 for connecting the four-cylinder parallel engine. 3. The four-cylinder parallel engine according to claim 1, wherein the inner thin steel plate 24 of each half-curved plate 5, 6 is made of alloy steel, and the outer thin steel plate 23 is made of non-alloy steel. bent pipe. 4. The insulating layer 25 is constructed as a stamped sheet of mineral fiber mat adapted to a certain area to form a conduit in the thin steel plates 23, 24. Bent pipe of cylinder parallel engine.