JPH07102993A - Exhaust temperature sensor mounting device for catalyst case - Google Patents

Abstract

(57) [Abstract] [Purpose] A boss provided at an exhaust temperature sensor mounting portion of a catalyst case of an exhaust system in an internal combustion engine of an automobile is prevented from being exposed to exhaust gas, and a harmful effect due to high heat does not occur. [Structure] Opening a hole 9 in the catalyst case 5 of the automobile exhaust system,
In an automobile in which the tip of the exhaust temperature sensor 12 is inserted into this hole 9 and the exhaust temperature sensor 12 is attached to the catalyst case 5 via the boss 10, the tip of the exhaust temperature sensor 12 passes through the hole 9 of the catalyst case 5. Only the tip of the exhaust temperature sensor 12 is inserted into this hole 9. Since the boss 10 is not exposed to the exhaust gas, it is not affected by the high heat.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust temperature sensor mounting device for a catalyst case, which is applied to an exhaust system of an internal combustion engine of an automobile.

[0002]

2. Description of the Related Art FIG. 3 shows an automobile engine and its exhaust system. Reference numeral 1 is an engine, 2 is an exhaust manifold, 3 and 4 are exhaust pipes, and 5 is a catalyst case. Seal rings 6 and 7 are provided at the connecting portions of the exhaust pipes 3 and 4 and the connecting portion of the exhaust pipe 4 and the catalyst case 5.

Although not shown in FIG. 3, the catalyst case 5 includes
An exhaust temperature sensor 12 (see FIG. 4 and FIG. 5) is attached to the outlet side of the exhaust temperature sensor 12 to monitor abnormal combustion in the catalyst. As a related technique of the present invention, there is one described in Japanese Utility Model Laid-Open No. 3-17112. In this publication, the catalyst case is divided into an upper member and a lower member to be manufactured, and an exhaust gas temperature sensor is attached to the joint portion where these are joined.

In any structure, the output signal of the exhaust gas temperature sensor is input to a control circuit using a microcomputer to take a warning when abnormal combustion occurs and take measures to prevent the abnormal condition from continuing. It is designed to be taken.

4 and 5 show the exhaust temperature sensor 12 mounted on the catalyst case 5. As shown in FIG. In this structure, a flat surface portion 8 is formed on the outlet side of the catalyst case 5, and a hole 9 is formed in the flat surface portion 8 by burring. An exhaust gas temperature sensor 12 is inserted into the stepped hole 11 and brought into close contact therewith, and is fixed by a screw (not shown) formed in the large diameter portion of the hole 11. The tip of the exhaust temperature sensor 12 serves as a heat sensitive part.

[0006]

In the prior art having such a structure, the boss 10 is exposed directly to the exhaust gas, so that the temperature becomes extremely high and the torque due to seizure or settling of the screw for mounting the exhaust temperature sensor is generated. There was a problem that down is likely to occur. The technologies described in the above publications also differ in structure, and therefore are not a solution to this problem.

The present invention has been made in view of this point, and an object of the present invention is to provide an exhaust gas temperature sensor mounting device for a catalyst case in which the boss 10 is not directly exposed to exhaust gas.

[0008]

As a means for solving the above problems, the present invention provides a hole in a catalyst case of an automobile exhaust system, and inserts a tip end portion of an exhaust gas temperature sensor into the hole, In an automobile in which a sensor is attached to the catalyst case via a boss, the hole of the catalyst case is sized so that the tip of the exhaust temperature sensor passes through, and only the tip of the exhaust temperature sensor is inserted into the hole. It is a thing.

Further, the exhaust temperature sensor is oriented vertically above the catalyst case or at an arbitrary angle with respect to the vertical direction.

Further, the portion of the catalyst case where the hole is formed is formed on a flat surface portion, and the bottom surface of the boss is brought into contact with the portion formed on the flat surface portion.

Further, the boss is formed in a cylindrical shape so that the hole diameter is reduced downward, and the lower portion of the exhaust gas temperature sensor is held by the slope portion of the hole.

Also, the outer peripheral portion of the lower end of the cylindrical boss and the flat portion of the catalyst case are fixed by welding.

[0013]

With this structure, since the boss is located outside the catalyst case, it is not directly exposed to the exhaust gas. As a result, it is possible to completely avoid the harmful effects caused by the heat of the boss.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. In the case of the present invention, the catalyst case 5
The size of the hole 9 provided in the flat surface portion 8 of the exhaust gas temperature sensor 12 is set so that the tip (heat-sensitive portion) of the exhaust gas temperature sensor 12 passes through (the size is slightly larger than the diameter of the tip of the exhaust gas temperature sensor 12). Only the tip of the sensor 12 is inserted. That is, as shown in FIG. 2, the hole 9 of the flat surface portion 8 and the small diameter portion of the hole 11 of the boss 10 have substantially the same diameter.

Although the exhaust temperature sensor 12 is oriented vertically above the catalyst case 5 in the drawing, the exhaust temperature sensor 12 is inclined at an arbitrary angle with respect to the vertical direction. So that it doesn't hit the floor of the vehicle,
And make it convenient for maintenance.

Further, a portion where the hole 9 of the catalyst case 5 is provided is formed in the flat portion 8, and the bottom surface of the boss 10 is brought into contact with the portion formed in the flat portion 8. As a result, the posture of the boss 10 becomes constant and stable.

Further, the boss 10 is formed in a cylindrical shape such that the diameter of the hole 11 is reduced downward, and the slope 11 of the hole 11 is formed.
The lower part of the exhaust temperature sensor 12 is held by a. This stabilizes the holding of the exhaust temperature sensor 12.

Further, the outer peripheral portion of the lower end of the cylindrical boss 10 and the flat surface portion of the catalyst case 5 are fixed by welding 13. Since the outer periphery of the boss 10 is welded, it can be performed easily.

Even in the exhaust gas temperature sensor mounting device for a catalyst case according to the present invention configured as described above, the exhaust gas temperature sensor
The 12 functions and usages are the same as the conventional ones. When the engine 1 is started and the exhaust gas flows through the catalyst case 5, the boss 10 is hardly exposed to the exhaust gas, so that it is not affected by the heat. Also, in the mounting process of the boss 10, high precision such as closely inserting into the hole of the conventional burring process is not required,
Workability is improved and there is no burring process, which is advantageous in terms of cost.

[0020]

Since the present invention is the exhaust temperature sensor mounting device for the catalyst case constructed as described above, since the boss is not exposed to the exhaust gas, the boss does not become hot. Therefore, it is possible to prevent torque down due to seizure or fatigue of the exhaust temperature sensor mounting screw portion provided on the inner circumference of the boss. Also, the positioning of the boss during assembly is stable, and mounting is easy. Since the burring process becomes unnecessary, the cost can be reduced accordingly.

[Brief description of drawings]

FIG. 1 is a perspective view of an embodiment of the present invention.

FIG. 2 is a vertical sectional view of a main part in FIG.

FIG. 3 is a perspective view showing an exhaust system of the engine in a partially disassembled state.

FIG. 4 is a perspective view showing a main part of a conventional technique corresponding to FIG.

5 is a vertical cross-sectional view of a main part in FIG.

[Explanation of symbols]

 1 Engine 5 Catalyst Case 8 Plane 9 Hole 10 Boss 11 Hole 11a Slope 12 Exhaust Temperature Sensor 13 Welding

Claims (5)

[Claims] 1. A hole is opened in a catalyst case of an automobile exhaust system,
In an automobile in which the tip of the exhaust temperature sensor is inserted into the hole and the exhaust temperature sensor is attached to the catalyst case via a boss, the hole of the catalyst case is sized so that the tip of the exhaust temperature sensor passes. An exhaust gas temperature sensor mounting device for a catalyst case, wherein only the tip of the exhaust gas temperature sensor is inserted into the hole. 2. The exhaust gas temperature sensor mounting device according to claim 1, wherein the exhaust gas temperature sensor is oriented vertically above the catalyst case or at an arbitrary angle with respect to the vertical direction. 3. The exhaust temperature of the catalyst case according to claim 1, wherein a portion of the catalyst case where the hole is formed is formed in a flat surface portion, and the bottom surface of the boss is brought into contact with the portion formed in the flat surface portion. Sensor mounting device. 4. The catalyst case according to claim 3, wherein the boss is formed in a cylindrical shape so that the hole diameter is reduced downward, and the lower portion of the exhaust gas temperature sensor is held by the sloped portion of the hole. Exhaust temperature sensor mounting device. 5. An exhaust gas temperature sensor mounting device for a catalyst case according to claim 3, wherein a lower end outer peripheral portion of the cylindrical boss and a flat surface portion of the catalyst case are fixed to each other by welding.