JPH0318265Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention relates to an exhaust system for a horizontally mounted engine mounted on an automobile.

[Prior Art] In the horizontally mounted engine of a front-wheel drive vehicle, in which the engine is mounted in the front of the vehicle body and drives the front wheels, the output shaft from the engine is arranged in the left-right direction of the vehicle.

As an exhaust system for a horizontal engine, for example, as described in Japanese Utility Model Publication No. 50-41382,
An exhaust pipe is provided that runs from the front of the horizontally mounted engine around the lower periphery to the rear. The upstream end of the exhaust pipe is fixed to the exhaust manifold side of the engine. Further, the downstream end of the exhaust pipe and the downstream exhaust pipe are connected via a flexible joint.

[Problems to be Solved by the Invention] In a horizontally mounted engine, a rolling component caused by the movement of the engine acts on the vehicle body as a pitching force. This force in the pitching direction is the same as the drive reaction force and increases the movement of the engine. As a result, the exhaust pipe located from the front to the bottom of the engine is subjected to large bending stress, metal fatigue progresses, and the strength of the exhaust system decreases, especially at the joints.

Further, the pitching component acts on the exhaust pipe as a force accompanied by longitudinal movement. Therefore, simply providing a flexible joint on the downstream side of the exhaust pipe cannot sufficiently cope with the movement in the pitching direction.

To solve this problem, for example, in Rex (a product name for automobiles), an exhaust pipe 2 is installed on the exhaust manifold side of the horizontal engine 1, as shown in Fig. 3.
An exhaust system is employed in which the exhaust upstream end of the exhaust pipe 2 is fixed, and the exhaust downstream end of the exhaust pipe 2 is connected to the downstream exhaust pipe 4 via an expandable stainless steel bellows-shaped joint pipe 3.

However, the exhaust system shown in FIG. 3 requires an expensive bellows-shaped joint pipe 3 made of stainless steel, leading to an increase in manufacturing costs. Further, due to pitting of the engine 1, movement having a component in the tube axis direction inevitably occurs in the bellows-shaped joint tube 3. Therefore, the joint tube 3 becomes easily fatigued due to repeated bending.

The present invention was devised to solve these problems, and it is a horizontally mounted engine that can sufficiently accommodate the movement of the engine in the pitting direction without using a bellows-shaped joint pipe, and can be manufactured at low cost. The purpose is to provide an exhaust system for

[Means for Solving the Problems] In order to achieve the purpose of the exhaust system for a horizontal engine of the present invention, the upstream end of the upstream exhaust pipe is connected to the exhaust manifold provided in the front position of the horizontal engine. The upstream exhaust pipe is connected via an upstream flexible joint, and the upstream exhaust pipe extends rearward from the front through the lower part of the outer periphery of the horizontal engine, and the downstream end thereof is connected via the downstream flexible joint. It is connected to a downstream exhaust pipe suspended from the vehicle body, and a line connecting the upstream flexible joint and the downstream flexible joint is located as close as possible to the pitching center of the horizontal engine. It is characterized by the presence of

[Examples] Hereinafter, the present invention will be specifically described by way of examples with reference to the drawings.

In this embodiment, as shown in FIG.
An exhaust manifold 11 is provided on the front side of a horizontal engine 10 of a FF vehicle. The upstream end of the upstream exhaust pipe 20 is connected to the exhaust manifold 11 via a flexible joint 30. Note that the reference numeral 12 indicates an air cleaner that communicates with the inside of the engine 10.

The upstream exhaust pipe 20 extends downward from the front along the outer peripheral shape of the engine 10, is bent, and further extends rearward below the engine 1. A downstream end of the upstream exhaust pipe 20 is connected to a downstream exhaust pipe 50 via a flexible joint 40.

Upstream exhaust pipe 20 facing downstream exhaust pipe 50
As shown in FIG.
2 is provided. The inner cylinder 21 has a flange 22
It extends in the axial direction from the inner peripheral side. Further, the rear part of the upstream exhaust pipe 20 is suspended from the engine 10 by an elastic member 23.

The downstream exhaust pipe 50 is located slightly rearward of the rear end of the engine 10. And elastic member 51
It is suspended from the vehicle body 52 by. Further, the downstream exhaust pipe 5 facing the upstream exhaust pipe 20
0 has a flange 5 on the end face as shown in Figure 2.
3 is provided. This downstream exhaust pipe 50 is
A muffler (not shown) or the like is attached, and the downstream end is open to the atmosphere.

A line 3-4 connecting the centers of the flexible joints 30 and 40 is placed as close as possible to the pitching center C of the engine 10. That is, line 3-
Both flexible joints 30 and 40 are arranged with respect to the engine 10 in such a manner that the joints 4 are as close to the pitching center C as possible.

As shown in FIG. 2, the flexible joint 40 includes a bolt 41 that connects the upstream exhaust pipe 20 and the downstream exhaust pipe 50. bolt 41
are inserted into bolt insertion holes provided at multiple locations in the circumferential direction of the flanges 22 and 53, with the coil springs 42 loosely fitted therein. A spring seat 43 for receiving one end of a coil spring 42 is attached to the head side of the bolt 41, and the coil spring 42 is disposed between the spring seat 43 and the flange 53. Also, flange 2
A nut 44 is attached to the leg of the bolt 41 extending from 2.
is screwed on. By tightening the nut 44, the coil spring 42 between the spring seat 43 and the flange 53 is compressed, and a force is applied between the flanges 22 and 53 in a direction toward each other.

A sealing connecting cylinder 45 is fitted into the inner cylinder 21 that protrudes in the axial direction from the inner peripheral side of the flange 22 . The flat side surface of the seal connecting cylinder 45 is supported by the side surface of the flange 22 that faces the flange 53. Further, a spherical arc surface 46 is formed on the outer periphery of the connecting cylinder 45. On the other hand, a spherical arc concave surface 47 having a shape corresponding to the spherical arc surface 46 is attached to the flange 22.
It is formed on the side surface of the flange 53 facing the flange 53.

Therefore, when aligning the spherical arc surface 46 and the spherical arc concave surface 47, inserting the inner cylinder 21 of the upstream exhaust pipe 20 into the downstream exhaust pipe 50, and tightening the nut 44, the coil spring 42 is compressed. Due to its elastic force, the connecting tube 45 is connected between the opposing surfaces of the flanges 22 and 53.
are held elastically.

Note that the exhaust manifold 11 and the upstream exhaust pipe 20
The flexible joint 30 provided between the two has almost the same structure, so its explanation will be omitted here.

In this way, in the exhaust system that goes around from the front of the engine 10 through the bottom and back, the exhaust manifold 11 and The connection point with the upstream exhaust pipe 20 and the upstream exhaust pipe 20 and the downstream exhaust pipe 5
The connection point with 0 is selected.

Therefore, when the engine 10 pitches around the center C using the car body as a reference, the movement in the pitching direction is caused by the movement of the flexible joint 30.
It acts in the direction of the arrow δ in FIG. 1 at the position . The other flexible joint 40 hardly moves in the axial direction and only swings. In this respect, the exhaust system is fundamentally different from the exhaust system shown in FIG. 3, in which motion is transmitted to the bellows joint tube 3 with a component in the tube axis direction.

Therefore, including the movement in the δ direction, the engine 1
0 movement in the pitching direction can be sufficiently absorbed. In addition, flexible joint 30,
40 and the pitching center C so that the distance from the flexible joint 30 to the pitching center C is equal to the distance from the flexible joint 40 to the pitching center C.
Preferably, 40 positions are set.

Moreover, flexible joint 30, 40
is a universal joint with a simple structure as shown in Figure 2. Therefore, compared to the conventional exhaust system that uses the stainless steel bellows-shaped joint 3 shown in Fig. 3, the entire exhaust system is It becomes possible to manufacture at low cost.

[Effects of the invention] As explained above, in the exhaust system of the invention, both ends of the upstream exhaust pipe of the exhaust system, which extends from the front of the horizontally mounted engine through the lower part to the rear, pass through the pitting center of the engine. It is connected to the exhaust manifold and downstream exhaust pipe via a flexible joint provided on the line. Therefore, at the connection point on the upstream side, the pitching engine and the upstream exhaust pipe move together, so the connection will not be broken. On the other hand, at the connection point on the downstream side, there is almost no movement in the axial direction, and only a rocking movement occurs. Therefore, a durable exhaust system that can sufficiently absorb engine pitching can be obtained.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram showing the exhaust system of a horizontal engine according to an embodiment of the present invention, Fig. 2 is a sectional view showing the structure of a flexible joint incorporated in the exhaust system, and Fig. 3 is a diagram of a conventional transverse engine. FIG. 2 is a schematic diagram showing an exhaust system for use. 10...Horizontal engine, 11...Exhaust manifold, 20...Upstream exhaust pipe, 30...Upstream flexible joint, 40...Downstream flexible joint, 50...Downstream exhaust pipe, C...
Center of engine pitching.

Claims (1)

[Scope of utility model registration request] The upstream end of the upstream exhaust pipe is connected to an exhaust manifold provided at the front of the horizontal engine through an upstream flexible joint, and the upstream exhaust pipe connects the outer periphery of the horizontal engine from the front. It extends rearward through the lower part, and its downstream end is connected to a downstream exhaust pipe suspended from the vehicle body via a downstream flexible joint,
An exhaust system for a horizontal engine, characterized in that a line connecting the upstream flexible joint and the downstream flexible joint is as close as possible to a pitching center of the horizontal engine.