JP2005036708A - Exhaust manifold of engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To realize remarkable raising of a thermal durability by inhibiting receiving of a thermal damage by welded parts of upstream side half and downstream side half of an exhaust manifold body with high temperature exhaust gas flowing in a manifold. <P>SOLUTION: The exhaust manifold made by this press includes an upstream side connecting flange 10 for communicating with an exhaust port 2 of an engine body 1, a downstream side connecting flange 20 for communicating with an exhaust tube so that an exhaust gas inlet 11 and an exhaust gas outlet 21 are coupled integrally with both the connecting flanges 10 and 20 for communicating with each other. A manifold body 30 is divided and molded to the upstream side half 30U fixed to the upstream side connecting flange 10 and the downstream side half 30L fixed to the downstream side connecting flange 20 so that the divided released surfaces are connected integrally. Its connecting part W is substantially perpendicularly crossed with its flowing direction so as not to be opposed to the flowing direction of an exhaust gas flowing in the manifold body 30. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an exhaust manifold provided in an exhaust system of an engine, and more particularly to an improvement of an exhaust manifold in which a manifold main body constituting a main part thereof is made of press.

Conventionally, an exhaust manifold of an exhaust system that is connected to an exhaust port opened in the cylinder head of an engine is manufactured by a press that connects the flange plate on the upstream side, the flange plate on the downstream side, and both the flange plates together. What consists of a manifold main body is well-known (refer following patent document 1).
JP-A-9-287445

  However, the press-made manifold main body of the conventional exhaust manifold is formed by dividing the upper half and the lower half into upper and lower parts and welding the peripheral edges of the half halves together. Because the exhaust gas flows along the flow direction of the exhaust gas flowing through the exhaust manifold, when hot exhaust gas discharged from the exhaust port of the engine flows in the manifold body, it directly hits the welded part and causes the deterioration of the welded part. As a result, there is a problem that the thermal durability of the entire exhaust manifold is impaired, and particularly when the combustion temperature is high and the temperature of the exhaust gas discharged from the exhaust port is high as in a diesel engine. Becomes even larger.

  The present invention has been proposed in view of the above, and an object of the present invention is to provide a novel engine exhaust manifold that solves the above problems.

In order to achieve the above object, the invention of claim 1 is directed to an upstream connection flange that opens an exhaust introduction port that communicates with an exhaust port of an engine body, and a downstream side that opens an exhaust outlet that communicates with an exhaust pipe. In the exhaust manifold of the engine, comprising a connecting flange and a manifold body made of a press integrally connected to both the connecting flanges and communicating the exhaust inlet and the exhaust outlet,
The manifold body is divided and formed into an upstream half that is fixed to the upstream connection flange and a downstream half that is fixed to the downstream connection flange, and the divided open surfaces are joined together. The joining portion is characterized by being substantially orthogonal to the flow direction so as not to face the flow direction of the exhaust gas flowing in the manifold body.

  In order to achieve the above object, the invention of claim 2 is characterized in that, in the invention of claim 1, the thickness of the press plate forming the upstream and downstream halves is changed. .

  Further, in order to achieve the above object, the invention of claim 3 is characterized in that, in the invention of claim 1 or 2, a supercharger is provided in the downstream half.

  According to the first aspect of the present invention, in an exhaust manifold of an engine having a press-made manifold main body, the manifold main body constituting the main portion includes an upstream half fixed to the upstream connection flange, and a downstream It is divided into a downstream half that is fixed to the side connection flange, and is formed by integrally joining the divided open surfaces, and the joint does not oppose the flow direction of the exhaust gas flowing through the manifold body. In this way, the exhaust gas is in a direction substantially perpendicular to the flow direction, and high-temperature exhaust does not directly hit the joint, and thermal damage to the joint can be reduced as much as possible. As a result, the manifold The main body is made of press, and the thermal durability of the exhaust manifold can be greatly enhanced while reducing the overall weight and size of the exhaust manifold.

  Further, according to the invention described in claim 2, since the plate thickness of the press plate forming the upstream and downstream halves is changed in the device described in claim 1, it can cope with the heat load applied to the manifold body. As described above, the thickness of the exhaust manifold can be further reduced without partially changing the thickness of the manifold body to increase the overall thickness of the manifold body more than necessary.

  Furthermore, according to the invention of claim 3, in the apparatus of claim 1 or 2, the supercharger is disposed in the downstream half, so that the thermal durability of the exhaust manifold is enhanced. High engine output can be achieved.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be specifically described below based on examples of the present invention shown in the accompanying drawings.

  In the accompanying drawings, FIG. 1 is a side view of a diesel engine equipped with an exhaust manifold of the present invention and equipped with a turbocharger (supercharger), FIG. 2 is an enlarged partial plan view of FIG. 2 is a side view taken along the line 3 in FIG. 2, FIG. 4 is a cross-sectional view taken along line 4-4 in FIG. 2, FIG. 5 is a cross-sectional view taken along line 5-5 in FIG. 6 is a sectional view taken along line 7-7 in FIG. 2, FIG. 8 is a sectional view taken along line 8-8 in FIG. 2, and FIG. 9 is an intake system of the engine. FIG. 2 is a system diagram of an exhaust system.

  In this embodiment, the exhaust manifold M of the present invention is applied to a multi-cylinder (4-cylinder) diesel engine E with a turbocharger T (supercharger). A plurality of (four) exhaust ports 2 communicating with each cylinder are opened in parallel on one outer surface along the crankshaft direction of the cylinder head 1H constituting the part. The exhaust manifold M according to the present invention for guiding the high-temperature exhaust discharged from the turbo charger T to the turbocharger T is fixed by a plurality of stud bolts 3 and nuts 4 (see FIG. 6).

  As shown in FIGS. 2 to 8, the exhaust manifold M includes an upstream connection flange 10 fixed to the cylinder head 1H, a downstream connection flange 20 to which the turbocharger T is fixed, and both flanges 10 and 20. It is comprised from the manifold body 30 made from a press couple | bonded together.

  As shown most clearly in FIGS. 4 and 5, the upstream connection flange 10 is formed in a long rectangular shape along the crankshaft direction of the engine body 1, and four ellipses are spaced apart in the longitudinal direction. Exhaust gas inlets 11 are opened to the front and rear surfaces of the exhaust gas inlets 11. The exhaust gas inlets 11 communicate with the exhaust ports 2. An EGR port 12 is opened at one end of the upstream connecting flange 10 (the left end in FIG. 4 and the right end in FIG. 5). The EGR port 12 is normally connected to the EGR passage 60 (see FIG. 9). ) To the intake system In of the engine E. Further, a plurality of bolt holes 13 are opened along the outer peripheral portion of the upstream connection flange 10, and the stud bolts 3 implanted in the cylinder head 1H are penetrated through the bolt holes 13. Further, three L-shaped stays 14 are fixed to the upper edge portion of the upstream connection flange 10 at intervals in the longitudinal direction, and the upper surface of these stays 14 protrudes upward from the upper edge portion. The cover 16 covering the upper half of the exhaust manifold M is fixed to the bolts and nuts 15 (see FIGS. 5 and 7).

  On the other hand, as shown most clearly in FIG. 3, the downstream connection flange 20 is formed in a triangular shape, and one exhaust outlet 21 is opened at the front and rear surfaces at the center thereof. . Three mounting bolts 22 are fixed outward at three corners of the downstream connection flange 20. The turbocharger T is fixedly supported on the outer surface of the downstream connection flange 20 by these mounting bolts 22 and nuts 23 screwed to them (see FIG. 1). The exhaust outlet 21 communicates with the inlet of the turbocharger T.

  Next, the structure of the manifold body 30 according to the present invention, in which the upstream side and downstream side connection flanges 10 and 20 are integrally joined, will be described. There are an upstream half 30U fixed to the upstream connection flange 10 and a downstream half 30L fixed to the upstream half 30U, both of which are formed by pressing a heat-resistant stainless steel plate. The thickness (3t) of the downstream half 30L is thicker than the upstream half 30U (2.5t). The upstream half 30U continuously surrounds the outer periphery of the four exhaust inlets 11 and the EGR port 12 and has a split open surface on the front surface, and is formed in an elongated container shape having a concave cross section. Four and one boss-shaped connection ports 31, 32 are opened on the wall surface so as to correspond to the four exhaust introduction ports 11 and the EGR port 12. These connection ports 31, 32 are welded to the four exhaust introduction ports 11 of the upstream connection flange 10 and the EGR port 12, respectively. On the other hand, the downstream half 30L has the same side shape as the upstream half 30U, has a split open surface on the front surface, and is formed in a semicircular vessel shape in cross section. As shown in FIG. 6, a through hole 35 is opened in the longitudinal intermediate portion of the downstream half 30 </ b> L, and the exhaust outlet 21 of the downstream connection flange 20 is communicated with the through hole 35. As shown in FIGS. 6 to 8, the split open surfaces of the upstream half 30U and the downstream half 30L are fitted to each other and welded together to form a sealed manifold body 30 made of press. It is formed.

  Therefore, the joint portion, that is, the welded portion W, between the upstream half 30U and the downstream half 30L is substantially parallel to the surface of the upstream connection flange 10 as shown in FIGS. In addition, it is in a direction substantially orthogonal to the flow direction of the exhaust gas so as not to oppose the flow direction of the exhaust gas flowing through the manifold body 30, that is, so that the exhaust gas does not directly hit.

  The EGR port 12 communicates with an EGR passage 60 connected to the intake manifold 42 via a passage 62 formed in the engine body 1 (see FIGS. 1 and 8).

  Next, the intake system In and the exhaust system Ex connected to the diesel engine E with the turbocharger T will be briefly described with reference to FIG. 9. The other outside along the crankshaft direction of the cylinder head 1H of the engine body 1 will be described. The intake pipes 42 are connected to the four intake ports 40... Opened on the side surface via an intake manifold 41. The intake pipe 42 is connected to the air cleaner 43 and the turbocharger T from the upstream side to the downstream side. The compressor 44 and the intercooler 45 are sequentially connected, and the air sucked from the air cleaner 43 is pressurized by the compressor 44, cooled by the intercooler 45, and supplied to the combustion chamber of the engine E through the intake port 40. The Further, as described above, the exhaust pipe 50 is connected via the exhaust manifold M to the four exhaust ports 2 opened in one outer surface along the crankshaft direction of the cylinder head 1H of the engine body 1. The exhaust pipe 50 is connected to the turbine 51 of the turbocharger T, the catalytic converter 52 and the silencer 53 sequentially from the upstream side to the downstream side, and the exhaust discharged from the exhaust port 2 is exhausted from the exhaust pipe 50. Then, the turbine 51 of the turbocharger T is rotationally driven by the exhaust pressure, and then purified through the catalytic converter 52, silenced through the silencer, and released to the atmosphere. Further, an EGR passage 60 communicates with the exhaust port 2 and the intake pipe 42, and an EGR valve 61 is interposed in the middle of the EGR passage 60. A part of the exhaust in the exhaust port 2 flows through the exhaust manifold M, then passes through the passage 62 and the EGR passage 60 in the engine body 1 (see FIG. 8), and is returned to the intake pipe 42 through the EGR valve 61. Reduce the amount of harmful components such as NOx. In FIG. 9, symbol J is a fuel injection valve.

  Next, the operation of this embodiment will be described.

  High-temperature exhaust gas generated by the operation of the diesel engine E is discharged from the four exhaust ports 2 and flows into the manifold body 30 through the four exhaust inlets 11 of the upstream connection flange 10. Exhaust gas in the manifold body 30 flows from the four exhaust inlets 11 to one exhaust outlet 21 as shown by arrows a in FIGS. Since the welds W of the bodies 30U and 30L are present in a direction substantially orthogonal to the flow direction so as not to face the flow direction, the high-temperature exhaust does not directly hit the weld W, and the weld W It is possible to reduce the thermal damage as much as possible to increase the thermal durability. Further, the thickness of the downstream half 30L to which the turbocharger T heated to a high temperature is fixed is larger than the thickness of the upstream half 30U so as to cope with the thermal load on the manifold body 30. In addition, the thickness of the manifold main body 30 is partially changed so that the thickness of the press manifold main body 30 is further reduced and reduced without increasing the overall thickness of the manifold main body 30 more than necessary. Thermal damage can be reduced and its thermal durability can be further increased. Further, the downstream half 30L that fixedly supports the turbocharger T is formed thicker than the upstream half 30U. It possesses the thermal strength that can sufficiently counter the heat load of the high-temperature turbocharger T, and can ensure high engine output.

  As mentioned above, although the Example of this invention was described, this invention is not limited to the Example, A various Example is possible within the scope of the present invention.

  For example, in the above embodiment, the case where the exhaust manifold M of the present invention is applied to the four-cylinder diesel engine E with the turbocharger T has been described. Moreover, although the said Example demonstrates the case where the manifold main body 30 was comprised by press molding of a stainless steel plate, you may comprise this with the heat-resistant metal plate which can be press-formed.

Side view of a diesel engine with a turbocharger (supercharger) equipped with the exhaust manifold of the present invention FIG. 1 is an enlarged partial plan view taken along line 2 of FIG. 3 is a side view taken along line 3 of FIG. Sectional view along line 4-4 in FIG. Sectional view along line 5-5 in FIG. Sectional view along line 6-6 in FIG. Sectional view along line 7-7 in FIG. Sectional view along line 8-8 in FIG. System diagram of intake system and exhaust system of diesel engine

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Engine body 2 ... Exhaust port 10 ... Upstream connection flange 11 ... Exhaust inlet 20 ... Downstream connection flange 21 ... Exhaust outlet 30 ... Manifold body 30U ·· Upstream half 30L · · Downstream half 50 ... exhaust pipe T ... supercharger (T)
W ・ ・ ・ ・ Joint part (welded part)

Claims (3)

An upstream connection flange (10) having an exhaust introduction port (11) communicating with an exhaust port (2) of the engine body (1) and an exhaust outlet (21) communicating with an exhaust pipe (50) are opened. The downstream connecting flange (20), and a manifold body (30) made of press that is integrally connected to both the connecting flanges (10, 20) and communicates the exhaust inlet (11) and the exhaust outlet (21). In the engine exhaust manifold,
The manifold body (30) is divided into an upstream half (30U) fixed to the upstream connection flange (10) and a downstream half (30L) fixed to the downstream connection flange (20). The split open surfaces are integrally joined to each other, and the joint (W) is substantially orthogonal to the flow direction so as not to oppose the flow direction of the exhaust gas flowing through the manifold body (30). The exhaust manifold of the engine, characterized by   2. The engine manifold according to claim 1, wherein the thickness of the press plate forming the upstream and downstream halves (30U, 30L) is changed. The engine exhaust manifold according to claim 1 or 2, wherein a supercharger (T) is disposed in the downstream half (30L).

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