JPS621379Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an exhaust system for an internal combustion engine in a front engine, front drive type automobile.

Generally used in the exhaust pipes of internal combustion engines such as automobiles, flexible flexible pipes are used to absorb relative displacement due to differences in thermal expansion in the exhaust system, as well as to isolate engine vibrations and reduce noise from the vehicle body. has been done.

Conventionally, in the case of a front engine, an exhaust pipe 2 extending rearward from the engine 1 as shown in FIG.
A flexible pipe 3 is installed near the entrance of the floor tunnel section,
Usually, a structure is adopted in which the exhaust pipe 2b rearward of the flexible pipe 3 is supported at the central cross member 9 of the floor.

However, with this conventional configuration, the flexible pipe 3
The distance of the exhaust pipe 2a at the front is longer, and the engine 1
The movement of the front end of the flexible pipe 3 due to the pitching movement of the machine becomes large, and in order to absorb this movement, the flexible pipe 3 must not only be made longer, but also a large space must be taken up in the floor tunnel, which is inconvenient. many.

The present invention is aimed at addressing the above-mentioned conventional disadvantages, and will be described below with reference to the embodiments shown in FIGS. 2 and 3.

In the present invention, as shown in FIGS. 2 and 3, the flexible pipe 3 is attached to the exhaust pipe 2 so as to be located at the center of the pitching movement of the engine 1, that is, below the pitching center A, and the flexible pipe 3 is attached to the exhaust pipe behind the flexible pipe 3. A bracket 4 provided at 2b extends forward and is supported at a peripheral position of approximately the center in the longitudinal direction of the flexible pipe 3 via an elastic material 6 such as a rubber hanger on an engine support member 5 such as a center member for an engine mount. It is.

In the figure, 7 indicates a muffler and 8 indicates a muffler hanger.

According to the present invention having the above configuration, since the flexible pipe 3 is provided below the pitching center of the engine 1, the pitching motion of the engine 1 causes a displacement mainly in the bending direction to the flexible pipe 3. 1
The rolling motion mainly gives a torsional component displacement to the flexible tube 3.

Furthermore, since the exhaust pipe 2b at the rear of the flexible pipe 3 is supported around the longitudinal center of the flexible pipe 3, the angular displacement of the exhaust pipe 2b causes the flexible pipe 3 to undergo a bending direction displacement.

Also, for the vertical vibration of the engine, the flexible pipe 3
Since it is located near the engine support part, vertical movement is very small.

Generally, when a corrugated pipe is subjected to shear bending, tension, or compression deformation, stress is concentrated at the joint with the exhaust pipe at both ends of the corrugated pipe, which is unfavorable in terms of strength, but it is preferable in terms of strength because the stress is dispersed when subjected to bending or torsional deformation. It has the characteristic of

Therefore, as mentioned above, the pitching movement of the engine,
The structure of the present invention, in which the flexible pipe mainly undergoes bending and torsional displacement due to rolling motion and angular displacement on the exhaust pipe side, is extremely favorable in terms of strength due to the characteristics of the flexible pipe, and the amount of displacement of the flexible pipe is extremely small. Therefore, the size of the flexible pipe can be significantly reduced compared to the conventional one, which is extremely advantageous in terms of cost and space.

Furthermore, in the present invention, the exhaust pipe at the rear of the serpentine pipe is supported by an engine support member with a high natural frequency via an elastic material, so it is possible to significantly reduce the noise inside the vehicle, and also to reduce the thermal radiation from the exhaust pipe. This can bring about extremely large practical effects, such as greatly reducing the influence.

In the above embodiment, the flexible pipe is located near the lower part of the pitching center of the engine, but even if the flexible pipe is located below the differential center B, almost the same functions and effects as described above can be obtained. .

[Brief explanation of the drawing]

FIG. 1 is an explanatory side view schematically showing a conventional exhaust system, and FIGS. 2 and 3 are an explanatory plan view and an explanatory side view showing an embodiment of the present invention. 1...engine, 2...exhaust pipe, 3...serpentine pipe,
4... Bracket, 5... Engine support member,
6...Elastic material, A...Pitching center, B...
differential center.

Claims (1)

[Scope of utility model registration request] In an exhaust system in which the front and rear exhaust pipes of an internal combustion engine of a front-engine, front-drive automobile are connected by a flexible flexible pipe, the flexible pipe is located below the pitching center or differential center of the engine, and the flexible pipe is located below the pitching center or differential center of the engine. 1. An exhaust system for an internal combustion engine for an automobile, characterized in that a bracket provided on a rear exhaust pipe extends forward and is supported by an engine support member via an elastic material at a position around the longitudinal center of the flexible pipe.