JPH0519537Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Field of Industrial Application) The present invention relates to an engine exhaust system.

(Prior Art) The exhaust manifold of an engine usually consists of an exhaust passage section connected to each exhaust passage opening end of the cylinder head, and a collective passage section that collects these passages on the downstream side of the exhaust gas. It has a generally shaped shape that extends laterally from the head and then curves downward. (See Figures 1 to 4).

In an exhaust manifold having such a shape and configuration, large thermal stress tends to concentrate at the boundary between the exhaust passage and the collective passage due to its thermal deformation.

As a countermeasure against such cracks in the exhaust manifold, for example, as disclosed in Japanese Patent Application Laid-open No. 60-50217, there has been a method in which the amount of thermal deformation of the exhaust passage portions is constant between adjacent exhaust passage portions of the exhaust manifold. It is known that stoppers are provided which come into contact with each other to suppress further thermal contraction when the heat shrinkage reaches a certain amount.

However, in this conventional example, the stopper formed between adjacent exhaust passages has a structure that can only restrict thermal deformation in one direction of the exhaust manifold, so the effect of suppressing thermal deformation is not sufficient, and cracks may occur. Concerns remain.

On the other hand, since the exhaust manifold becomes extremely hot due to exhaust heat, especially when an electrical item such as an O ₂ sensor is attached to the exhaust manifold, the function of the O ₂ sensor may deteriorate due to the influence of heat. In addition, overheating may cause secondary heat damage such as the tightening nuts of the exhaust manifold becoming more likely to loosen.

(Purpose of the invention) The present invention is an attempt to solve or improve the problems pointed out in the above section of the prior art. It is an object of the present invention to provide an engine exhaust system that suppresses as much as possible the occurrence of secondary heat damage due to overheating of an exhaust manifold.

(Means for Achieving the Object) As a means for achieving the above object, the present invention provides an exhaust manifold that is fastened to the side end surface of the cylinder head, and a mounting flange that is fastened to the side end surface of the cylinder head. A plurality of exhaust passage portions each having a shape extending from the side toward the side of the engine and then curving in the longitudinal direction, and an exhaust collection portion that collects the exhaust passage portions on the downstream side;
In an engine exhaust system that introduces running wind into the exhaust manifold from the side facing the exhaust manifold, reinforcement extending substantially horizontally between adjacent exhaust passages of the exhaust manifold is provided. They are connected by ribs, and one end side of the space surrounded by the reinforcing ribs, the exhaust passage section, and the exhaust collecting section is opened in a state facing the running wind, and this serves as a running wind inlet; The other end is opened closer to the end face on the cylinder head side than the running wind inlet and toward the top, and this is used as a running wind exhaust port, so that the running wind is discharged from the running wind inlet side in the space. It is configured so that it flows toward the exit.

(Function) In the present invention, by the above means, (1) Since the adjacent exhaust passage sections of the exhaust manifold are integrally connected by the reinforcing ribs, thermal deformation of the exhaust manifold is caused by the reinforcing ribs. (2) between adjacent exhaust passage sections, an exhaust collection section that collects them, and the above exhaust passage sections; The space surrounded by the reinforcing ribs provided astride functions as a flow path for running wind, and the running wind is introduced from the running wind inlet opening opposite to this, and is then directed to the running wind outlet side. Since the airflow is made to flow along the direction of the air flow, the exhaust gas collecting section, which is a particularly hot area in the exhaust manifold, is effectively cooled by the running wind, and secondary heat damage caused by overheating of this portion, such as the exhaust collecting portion, is effectively cooled. This prevents deterioration in the functionality of electrical components such as O ₂ sensors installed in the parts, as well as gas leaks due to loosening of the exhaust manifold tightening nuts installed near the exhaust collecting parts. The following effects can be obtained.

(Embodiment) Hereinafter, a preferred embodiment of the present invention will be described with reference to FIGS. 1 to 4.

(First Embodiment) FIGS. 1 and 2 show an exhaust manifold 1 applied to an exhaust system for an in-line four-cylinder automobile engine according to a first embodiment of the present invention. In the figure, reference numeral 50 indicates a cylinder block 51.
and a cylinder head 52.

The exhaust manifold 1 simultaneously communicates with two head-side exhaust passages 53, 53 corresponding to the two cylinders on the left among the four cylinders of the engine, and collects the exhaust from the two head-side exhaust passages 53, 53. The exhaust from the first exhaust passage section 2 that leads to the center of the cylinder head 52 and the two head-side exhaust passages 53, 53 corresponding to the two cylinders on the right side are collected and routed to the center of the cylinder head 52. A second exhaust passage section 3 leading to the cylinder head, and a rear exhaust pipe 10 by combining the first exhaust passage section 2 and the second exhaust passage section 3 at the center of the cylinder head.
an exhaust collection section 4 leading to the exhaust gas, and the first exhaust passage section 2
and a mounting flange portion 6 connected to the exhaust upstream end of the second exhaust passage portion 3 are integrally formed by casting. Further, the first exhaust passage section 2 and the second exhaust passage section 3 disposed on the left and right sides of the exhaust manifold 1, respectively, are arranged as shown in FIG. The cylinder head 52 extends outward in a substantially horizontal direction from the mounting flange portion 6 and then curves downward. The passage has a configuration that curves in a substantially V-shape toward the exhaust gas collecting portion 4 side.

This exhaust manifold 1 has its mounting flange portion 6 connected to the exhaust side end surface 52a of the cylinder head 52.
the entire circumference 8 of the mounting flange portion 6.
The engine main body 50 side is tightened by nine mounting bolts 7, 7 placed at a total of nine locations where the first exhaust passage section 2 and the second exhaust passage section 3 meet. mounted on.
In addition, the exhaust collecting part 4 is provided with air-fuel ratio control.
An O ₂ sensor 8 is screwed on.

Further, by applying the present invention, a reinforcing rib 5 extending substantially horizontally is integrally formed between the first exhaust passage section 2 and the second exhaust passage section 3 of the exhaust manifold 1. In the longitudinal center portion of the exhaust manifold 1, the reinforcing rib 5, the left and right pair of first exhaust passage portions 2, second exhaust passage portions 3, and exhaust collecting portion 4 extend horizontally outward (towards the cylinder head). A substantially triangular cavity 11 is formed that opens on the lateral side. In this case, the front end edge 5a of the reinforcing rib 5 is extended to near the front surfaces of the first exhaust passage section 2 and the second exhaust passage section 3, and is used to introduce the running wind A into the space 11. A running wind inlet 12 is formed. On the other hand, the rear end edge 5b of the reinforcing rib 5 is located at a position separated by an appropriate distance from the mounting flange 6 or the cylinder head 5.
A traveling wind exhaust port 13 that opens upward is formed between the exhaust side end surface 52a of the exhaust gas and the exhaust side end surface 52a of the exhaust gas. That is,
The space 11 constitutes a generally L-shaped running air passageway 17 extending from a running air inlet 12 that opens toward the side of the engine to a running air outlet 13 that opens upward.

When mounting the engine, the mounting method and the like are determined so that the running wind inlet 12 of the running wind flow passage 17 opens to face the running wind.
Specifically, for example, in the case of an in-line engine, it is sufficient to place it horizontally so that its exhaust manifold faces forward in the direction of vehicle travel, and in the case of a longitudinally-arranged in-line engine or a V-type engine, an appropriate duct may be installed. The device may be used to guide the wind from the vehicle toward the exhaust manifold.

In an exhaust system equipped with the exhaust manifold 1 configured as described above, the exhaust manifold 1 becomes overheated in an operating range where the exhaust gas temperature is high, such as during high load operation of the engine, and the exhaust manifold 1 becomes overheated in the exhaust collecting section under particularly severe heat load conditions. A compressive force P or a tensile force Q is applied to the four portions due to thermal deformation of the exhaust manifold 1. However, in this example,
The reinforcing rib 5 extending substantially horizontally is formed between the first exhaust passage section 2 and the second exhaust passage section 3 so as to straddle the exhaust collecting section 4. Since the first exhaust passage section 2 and the second exhaust passage section 3 are interconnected, the above compressive force P
Alternatively, a part of the tensile force Q (the load is reversed and becomes the tensile force P and the compressive force Q when the engine is cooled after stopping operation) is supported by the reinforcing ribs 5,
Thermal deformation in the exhaust gas collecting portion 4 of the exhaust manifold 1 is suppressed as much as possible. Therefore, the occurrence of cracks due to excessive thermal stress is reliably prevented, and its durability is improved.

Further, in this embodiment, as described above, the reinforcing rib 5 connects the running air flow path to the confluence of the first exhaust passage section 2, the second exhaust passage section 3, and the exhaust gas collection section 4 of the exhaust manifold 1. 17, and its running wind inlet 12 is opened to face the running wind, so that the running wind generated as the vehicle runs is directed in the direction of flow as shown by arrow A in FIG. It flows smoothly into the running air flow path 17 from the running air inlet 12 while maintaining the same temperature, intensively cools the exhaust collecting section 4, and then is discharged from the running air outlet 13, thereby effectively discharging the air into the exhaust manifold 1. to cool the high temperature parts of the Therefore, the thermal deformation of the exhaust manifold 1 itself is suppressed and the occurrence of cracks is prevented, and at the same time, the O ₂ sensor 8 provided facing the travel airflow passage 17 is cooled, and functional deterioration due to the thermal influence is prevented. , mounting bolt 7
Natural unthreading of the nut 16 screwed into the exhaust manifold 1 is prevented, and secondary heat damage caused by overheating of the exhaust manifold 1 is prevented.

If the insulator 9 is attached to the outside of the exhaust manifold 1 as shown by the reference numeral 9 in FIG. 14, and furthermore, when a guide piece 15 is provided around the periphery of the opening 14 to guide the traveling wind towards the traveling wind inlet 12 side, the cooling effect of the exhaust manifold 1 by the traveling wind can be further enhanced. , more effective as a measure against heat damage, etc.

(Second Embodiment) FIGS. 3 and 4 show one exhaust manifold 21 of a pair of left and right exhaust manifolds applied to a V type 6-cylinder automobile engine according to a second embodiment of the present invention. It is shown. This exhaust manifold 1 independently forms three exhaust passage portions 22, 23, 24 each having a substantially square shape, and each exhaust passage portion 22, 23, 24 is approximately horizontal at its downstream end. They are configured to be assembled by an exhaust collection part 25 extending in the direction, and have a generally E-shaped outer shape as a whole.

Further, this exhaust manifold 21 is connected to the first
Similar to the exhaust manifold 1 of the embodiment, reinforcing ribs 27, 27 are formed between the adjacent exhaust passage portions 22, 23 and 23, 24, respectively, and extend substantially horizontally. The exhaust passage portions 22, 23, and 24 are connected in the horizontal direction. Also, below each reinforcing rib 27, 27, a space 31, 31, which functions as a travel airflow passage 37, is formed, respectively. This traveling wind flow passage 37
The opening end located on the front edge 27a side of the reinforcing rib 27 serves as a running wind inlet 32, and the opening end located on the rear edge 27b side of the reinforcing rib 27 and opening upward serves as a running wind inlet 32. A discharge port 33 is provided.

Therefore, also in this embodiment, the reinforcing ribs 27,
27 prevents the occurrence of cracks in the exhaust collecting part 25, and also directs the running wind to the above-mentioned running wind inlet 3.
By introducing the exhaust gas into the engine room so as to face the exhaust gas collecting portion 25, it is possible to prevent secondary heat damage caused by overheating of the exhaust gas collection portion 25.

(Effects of the invention) The present invention extends the exhaust manifold, which is fastened and fixed to the side end surface of the cylinder head, from the mounting flange part which is fastened to the side end surface of the cylinder head, toward the side of the engine, and then extends the exhaust manifold in the longitudinal direction. The exhaust manifold is composed of a plurality of exhaust passage sections having a curved shape and an exhaust collection section that collects the exhaust passage sections on the downstream side thereof, and the running wind is introduced into the exhaust manifold from the side thereof in an opposing state. In the engine exhaust system, adjacent exhaust passage portions of the exhaust manifold are connected by a reinforcing rib extending substantially horizontally, and the reinforcing rib, the exhaust passage portion, and the exhaust collecting portion are connected to each other. One end of the space surrounded by the cylinder head is opened facing the running wind, and this is used as a running wind inlet, and the other end of the space is opened at a position closer to the end face of the cylinder head side than the running wind inlet, and above the running wind. The vehicle is characterized in that the vehicle is opened toward the vehicle and serves as a traveling wind outlet, and the vehicle is configured such that the traveling wind flows through the space from the traveling wind inlet side toward the traveling wind outlet. .

Therefore, according to the engine exhaust system of the present invention, (1) Adjacent exhaust passage sections of the exhaust manifold are integrally connected by the reinforcing ribs, so that thermal deformation of the exhaust manifold is prevented. The reinforcing ribs effectively suppress and reliably prevent cracks from occurring due to thermal deformation of the exhaust manifold. (2) Adjacent exhaust passage sections, an exhaust collection section that brings together the exhaust passage sections, and the above-mentioned exhaust passage section. The space surrounded by the reinforcing ribs provided across the space functions as a flow path for running wind, and the running wind is introduced from the running wind inlet opening opposite to this and flowing to the running wind outlet side. Moreover, since the air flows along the direction of the running wind, the exhaust manifold's exhaust collecting section, which is a particularly hot part, is effectively cooled by the running wind, which prevents secondary heat damage due to overheating of this part. For example, in the case where an electrical component such as an O ₂ sensor is installed in the exhaust gas collecting section, the deterioration of its function and gas leakage due to loosening of the exhaust manifold tightening nuts installed near the exhaust gas collecting portion can be prevented. As a result, great effects can be obtained in terms of improving the durability of the exhaust manifold and reducing secondary heat damage caused by overheating of the exhaust manifold.

[Brief explanation of the drawing]

FIG. 1 is a front view of an exhaust manifold applied to an exhaust system according to a first embodiment of the present invention, FIG. 2 is a vertical cross-sectional view of FIG. 1, and FIG. 3 is a second embodiment of the present invention. FIG. 4 is a front view of the exhaust manifold applied to the exhaust system according to the example, and FIG. 4 is a vertical sectional view taken along the line shown in FIG. 1, 21...exhaust manifold, 2, 3, 2
2, 23, 24... Exhaust passage section, 4, 25... Exhaust collecting section, 5, 27... Reinforcement rib, 6, 26...
Mounting flange part, 7...Mounting bolt, 8...O ₂
Sensor, 9... Insulator, 12, 32...
Traveling wind inlet, 13, 33... Traveling wind outlet, 1
7, 37... Traveling wind flow path.

Claims (1)

[Scope of utility model registration request] An exhaust manifold that is fastened to the side end surface of the cylinder head is connected to a plurality of exhaust manifolds that extend toward the side of the engine from the mounting flange that is fastened to the side end surface of the cylinder head, and then curve in the vertical direction. An exhaust system for an engine comprising a passage part and an exhaust collecting part that collects the exhaust passage parts on the downstream side thereof, and in which running wind is introduced into the exhaust manifold from the side thereof in an opposing state. Adjacent exhaust passage portions of the exhaust manifold are connected by a reinforcing rib extending substantially horizontally, and a space surrounded by the reinforcing rib, the exhaust passage portion, and the exhaust collecting portion is One end side is opened to face the running wind, and this serves as a running wind inlet, and the other end of the space is opened closer to the cylinder head side end face than the running wind inlet, and also facing upward. An exhaust system for an engine, characterized in that the engine exhaust system is configured such that the running wind is a running wind exhaust port, and the running wind flows through the space from the running wind inlet side toward the running wind exhaust port.