JP4540111B2 - Rib structure of exhaust manifold - Google Patents

Description

  The present invention relates to a rib structure of an exhaust manifold of an internal combustion engine.

The engine output of vehicle engines is on the rise for improving transport efficiency and comfortable and safe driving. An increase in engine output promotes an increase in engine heat generation and raises the exhaust temperature.
When the exhaust temperature rises, the exhaust manifold is subjected to a further heat load.

  To better understand the present invention, a conventional exhaust manifold and its rib structure will be described with reference to FIGS.

  FIG. 5 is a view showing the manifold assembly 101 of the engine whose output is increased. In FIG. 5, the manifold assembly 101 includes a first manifold 10, a second manifold 20, and a central manifold 30.

  The first manifold 10 and the central manifold 30, and the second manifold 10 and the central manifold 30 are both accordion-type flexible tubes 40 and 40 in order to absorb the distortion of the connection between the manifolds due to thermal expansion. Connected by.

The first manifold 10 includes a first flange 11 </ b> F that is one end of the first manifold 10 and has a first port (opening) 11, and a second flange 12 </ b> F that has a second port 12. The first flange 11F is connected to the flange of the exhaust port on the first cylinder side of the engine having 6 cylinders (not shown), and the second flange 12F is the exhaust on the second cylinder side of the engine (not shown). Connected to the port flange.
As shown in detail in FIG. 6, the end face (attachment surface) of the first flange and the end face (attachment surface) of the second flange have the same extension surface. In the figure, a two-dot chain line Fv indicates the same extended surface (virtual surface).

  At the other end portion of the first manifold 10, a connection portion 17 with the flexible tube 40 is formed, and the inner periphery of the end portion of the flexible tube 40 is fitted to the outer periphery of the connection portion 17. It is configured.

  The first manifold 10 has a uniform protrusion amount from the outer periphery of the tubular portion 10P on the first and second flanges 11F, 12F side of the tubular portion 10P between the first port 11 and the second port 12. One rib 11r is formed.

  Furthermore, the 2nd rib 12r which has the uniform protrusion amount from the outer periphery of the tubular part 10P is formed in the opposite side to the 1st and 2nd flanges 11F and 12F of the tubular part 10P.

  In addition, the boss | hub part 10B for heat protector which is not shown in figure is formed in three places so that the middle of the 2nd rib 12r may be interrupted | blocked.

  The tubular portion 10P in which the first rib 11r is formed is inclined so as to gradually move away from the end surface (mounting surface) of the first flange 11F from the first flange 11F toward the second flange 12F. Therefore, on the second flange 12F side of the first rib 11r, the top 11rt of the rib is separated from the mounting surface of the second flange 12F by a considerable amount (λ).

  Referring again to FIG. 5, the second manifold 20 includes a sixth flange 26 </ b> F having one port 26 at one end of the second manifold 20 and a fifth port 25. The sixth flange 26F is connected to the flange of the exhaust port on the sixth cylinder side of the engine, and the fifth flange 25F is the exhaust port on the fifth cylinder side of the engine. Connected to the flange.

  Although not clearly shown in the drawing, a connection portion with the flexible tube 40 is formed at the other end portion of the second manifold 20, and is formed on the outer periphery of the connection portion. It is comprised so that the inner periphery of the edge part of the flexible tube 40 may be fitted.

  Although description using a single product drawing is omitted, the second manifold 20 has a third rib 23r (corresponding to the first rib 11r in FIG. 6) and a fourth rib 24r (similar to the first manifold 10). 6 (corresponding to the second rib 12r in FIG. 6) is formed (see FIG. 5 above).

  In the second manifold 20, an exhaust gas extraction flange 2F of the EGR mechanism is formed so as to block the middle of the fourth rib 24r (see FIG. 5 above).

With continued reference to FIG. 5, the central manifold 30 is substantially symmetrical with respect to the axial (longitudinal) center and is not clearly shown in the figure, but at both ends in the axial direction, a flexible tube 40 is provided. The connection part is formed. A flange 33F having a third port 33 and a flange 34F having a fourth port 34 are formed at positions symmetrical from the center near both ends.
Further, a flange 3F having an exhaust port is formed in the manifold center for connection with a turbocharger (not shown) on the opposite side of the shaft center from the third and fourth flanges 33F, 34F.

  As described above, the output of this engine is increased and the calorific value is also increased. With the increased amount of heat generated, when the entire manifold 101 is attached to the engine, a force in the extending direction (arrow Y1) acts on the first rib 11r on the attachment surface side with respect to the first manifold 10, A force in the direction (arrow Y2) for contracting the tube wall acts on the second rib 12r on the side opposite to the mounting surface.

  Similarly, in the second manifold, a force in the extending direction (arrow Y3) acts on the third rib 23r on the mounting surface side, and the tube wall is contracted on the fourth rib 24r on the side opposite to the mounting surface. A force in the direction to be bent (arrow Y4) acts.

In particular, the extensional force (thermal deformation force) acting on the first rib 11r of the first manifold 10 and the extensional force (thermal deformation force) acting on the third rib 23r of the second manifold 20 are: , Stress concentration is caused at the base of the flanges 12F and 25F on the side close to the flexible tube 40.
The material of the first and second manifolds 10 and 20 is cast iron (ductile), is weaker to tension than compression, and has a thermal history state (thermal deformation during repeated changes from low temperature to high temperature and from high temperature to low temperature). Depending on the degree, the ribs 11r and 23r may be damaged such as cracks.

  A technique has been proposed in which thermal deformation due to exhaust temperature is mitigated, exhaust gas leakage is prevented, and the assembly process is reduced (see, for example, Patent Document 1).

However, these proposals are intended to prevent leakage of exhaust gas and reduce the assembly process, and do not solve the above-described problems.
Japanese Utility Model Publication No. 4-119328

  The present invention has been proposed in view of the above-described problems of the prior art, and is capable of suppressing the amount of thermal deformation on the expansion side of the manifold even when the exhaust temperature is increased, and can sufficiently cope with an increase in engine output. The purpose is to provide a manifold rib structure.

  According to the present invention, the first manifold (1) and the second manifold (2) at both ends and the middle manifold (30) at the middle are divided into bellows type flexible tubes (40, 40). And an exhaust manifold (100) in which a flange (3F) having an exhaust port connected to the turbocharger is connected to the central manifold (30) on the opposite side of the engine. In the structure of reinforcing ribs (11R, 23R) provided between the ports (11, 12:25, 26) of the first and second manifolds (1, 2) at the end of the manifold (100), The engine side edge portions (11Rt, 23Rt) of the reinforcing ribs (11R, 23R) are adjacent to the adjacent port (11, 12, 25, 26) side end surfaces. A virtual surface (Fv) that extends parallel to the connecting virtual surface (Fv) and connects the engine side edge portions (11Rt, 23Rt) of the reinforcing ribs (11R, 23R) and the adjacent port side end surfaces. The flange (11F, 12F: 25F, 26F) provided in the exhaust manifold port portion (11F, 12F: 25F, 26F) and the flange provided in the exhaust port of the engine It is formed at an interval that can be joined to (not shown).

  The rib structure of the exhaust manifold of the present invention having such a structure is the engine side edge portion of the reinforcing rib (11R, 23R) provided between the ports (11, 12; 25, 26) of the exhaust manifold (1, 2). (11Rt, 23Rt) extends in parallel with the virtual surface (Fv) connecting the end faces on the adjacent ports (11 and 12; 25 and 26) of the exhaust manifold (1, 2), and the reinforcing rib (11R , 23R) and the gap (δ) between the engine side edge (11Rt, 23Rt) and the imaginary surface (Fv) that connects the end surfaces on the adjacent ports (11 and 12; 25 and 26) of the exhaust manifold. Flanges (11F, 12F; 25F, 26F) provided on the port portions (11, 12; 25, 26) of (1, 2); Increases to the extent that makes it possible to bond a flange provided on the exhaust port of the engine, and, for the distance is formed as small as possible, deformation due to heat is suppressed small.

  As a result of the small thermal deformation, the exhaust manifold (10, 20) is not damaged by heat.

  Since there is no risk of damage due to heat, it is possible to respond sufficiently to engine output increases.

Hereinafter, an embodiment of the present invention (denoted by reference numeral 100 as a manifold assembly) will be described with reference to the accompanying drawings (FIGS. 1 to 4).
The embodiment of the present invention is different from the above-described prior art exhaust manifold 101 only in the shape of the reinforcing rib provided between the ports, and only the different reinforcing rib will be described below.
In the following description, the same parts are denoted by the same reference numerals to avoid overlapping description.

  First, before entering the description of the reinforcing rib, the manifold assembly 100 will be described with reference to FIG.

  As shown in FIG. 4, the manifold assembly 100 according to the present embodiment includes a first manifold 1, a second manifold 2, and a central manifold 30.

  The first manifold 1 and the central manifold 30, and the second manifold 2 and the central manifold 30 are both accordion-type flexible tubes 40, 40 in order to absorb the distortion of the connection between the manifolds due to thermal expansion. Connected by.

  Next, the reinforcement rib 11R of the first manifold 1 will be described with reference to FIGS.

  The first flange 11F and the second flange are formed in the tubular portion 10P between the first flange 11F having the first port 11 of the first manifold 1 and the second flange 12F having the second port 12. A first rib 11R is provided so as to connect 12F.

  The engine side edge (rib top) 11Rt of the first rib 11R is an end surface on the side of the adjacent ports 11 and 12 of the first manifold 1, that is, an end surface of the first flange 11F and an end surface of the second flange 12F. (Mounting surface) extends in parallel with a virtual surface Fv indicated by a two-dot chain line that connects the two, and an interval δ between the engine side edge (the top portion of the rib) 11Rt of the reinforcing rib 11R and the virtual surface Fv is 2 mm or less.

  Here, the distance δ between the engine side edge (rib top) 11Rt of the first reinforcing rib 11R and the virtual surface Fv is 2 mm or less because the first flange 11F of the first manifold 1 and the first flange 11R When the mounting surface of the second flange 12F is connected to a flange surface provided in an exhaust port (not shown) of the engine, for example, even if various tolerances are taken into consideration, the casting surface on the engine side is the reinforcing rib of the first manifold. Even if there is an increase in the amount of heat generated due to increased engine output, the maximum value of the gap where the thermal deformation amount and thermal stress (stress concentration) acting on the ribs are within the allowable range is 2 mm. It is based on that it is.

The second manifold 2 in FIG. 3 is also similar to the first manifold in FIG. 1 and FIG. 2 at the end faces on the adjacent ports 25 and 26 side of the second manifold 2, that is, the end face of the fifth flange 25F and the sixth flange. A third reinforcing rib 23R extending in parallel with a virtual surface Fv indicated by a two-dot chain line connecting the end surfaces (mounting surfaces) of 26F is formed.
And the clearance gap between the engine side edge part (rib top part) 23Rt of the 3rd reinforcement rib 23R and the said virtual surface Fv is formed in 2 mm or less.

  As described above, the reinforcing ribs 11Rt and 23Rt of the first manifold 1 and the second manifold 2 of the exhaust manifold 100 are connected to the top portions 11Rt and 23Rt of the ribs and the mounting surfaces of the flanges (the mounting surface of the 11F and the 12F). The distance δ between the mounting surface, the mounting surface of 25F and the virtual surface Fv connecting the mounting surface of 26F) is the flange (11F, 12F; 13F, 14F) of the exhaust manifold 1 and the flange provided at the exhaust port of the engine. Therefore, the deformation due to heat is suppressed to be small because the distance δ is as small as possible (δ ≦ 2 mm).

  As a result of suppressing thermal deformation to a small extent, the exhaust manifold 100 is not damaged by heat due to thermal stress.

  Since there is no risk of damage due to heat, it is possible to respond sufficiently to engine output increases.

  It should be noted that the illustrated embodiment is merely an example, and is not a description to limit the technical scope of the present invention.

The top view explaining the 1st manifold concerning the embodiment of the present invention. FIG. 2 is an elevation view corresponding to FIG. 1. The top view explaining the 2nd manifold concerning the embodiment of the present invention. The top view of the manifold assembly which concerns on embodiment of this invention. The top view of the manifold assembly in a prior art. The top view of the single item of the 1st manifold in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... 1st manifold 2 ... 2nd manifold 10P ... Tubular part 11 ... 1st port 11F ... 1st flange 11R ... 1st rib 11Rt ... Top portion 12 ... second port 12F ... second flange 12r ... second rib 17 ... connecting portion 23R ... third rib 23Rt ... top portion 24r ... fourth Rib 25 ... fifth port 25F ... fifth flange 26 ... sixth port 26F ... sixth flange 30 ... central manifold 40 ... flexible tube

Claims (1)

  It is divided into a first manifold (1) and a second manifold (2) at both ends and a central manifold (30) at the middle, and is connected to each other by a bellows type flexible tube (40, 40). The central manifold (30) is an exhaust manifold (100) having a flange (3F) having an exhaust port connected to a turbocharger on the opposite side of the engine, and the exhaust manifold (100) In the structure of reinforcing ribs (11R, 23R) provided between the ports (11, 12:25, 26) of the first and second manifolds (1, 2) at the end, the reinforcing ribs (11R, 23R) ) Engine side edges (11Rt, 23Rt) are virtual surfaces that connect the end faces of adjacent ports (11 and 12, 25 and 26) Fv) extends in parallel with the distance (δ) between the engine-side edge portions (11Rt, 23Rt) of the reinforcing ribs (11R, 23R) and the virtual surface (Fv) connecting the adjacent port-side end surfaces. ) Is 2 mm or less, and the flange (11F, 12F: 25F, 26F) provided in the port portion (11, 12:25, 26) of the exhaust manifold and the flange provided in the exhaust port of the engine are joined. A rib structure of an exhaust manifold, characterized by being formed at a possible interval.

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