JPH0129969B2 - - Google Patents

Description

Detailed Description of the Invention The present invention relates to a vehicle in which a front engine block and a rear engine block are arranged along the longitudinal direction of the vehicle, and a crankshaft is arranged in a direction perpendicular to the longitudinal direction of the vehicle. This invention relates to an exhaust pipe device for a horizontal multi-cylinder engine.

In the multi-cylinder engine, both the front exhaust pipe connected to the front exhaust manifold fixed to the exhaust port of the front engine block and the rear exhaust pipe connected to the rear exhaust manifold fixed to the exhaust port of the rear engine block are connected to the vehicle. In an exhaust pipe device that extends rearward and communicates the exhaust pipes with the exhaust gas collection chamber, the lengths of the front and rear exhaust pipes and their routing are different, and the distance between the two exhaust pipes, especially the front and rear exhaust pipes, is different. Because the difference in the amount of thermal expansion in each direction is large, repeated heating and cooling of these parts causes thermal stress and eventually thermal strain, which causes the front and rear exhaust pipes to be displaced or deformed. It was hot.

In order to solve this problem, a part of the rear exhaust pipe is made of a telescopic flexible pipe to reduce the thermal strain that occurs in the front and rear exhaust pipes due to the expansion, contraction, and bending of the flexible pipe. It is possible that it may be absorbed, but
In that case, the vertical vibration of the downstream part of the rear exhaust pipe and the exhaust gas collection chamber than the telescopic flexible pipe acts biasedly on the front exhaust pipe, which is longer than the rear exhaust pipe and is inherently prone to stress. As a result, stress tends to concentrate on the front exhaust pipe and the telescopic flexible pipe itself, resulting in a problem that their durability is impaired.

An object of the present invention is to provide an exhaust pipe device for a vehicle engine that can solve all of the above-mentioned problems and problems. In a horizontal multi-cylinder engine for a vehicle, in which the crankshaft is arranged in a direction perpendicular to the longitudinal direction of the vehicle, a front exhaust pipe is connected to a front exhaust manifold fixed to the front engine block, A rear exhaust pipe, a portion of which is formed by a telescoping flexible pipe, is connected to the rear exhaust manifold fixed to the rear engine block, and both the front and rear exhaust pipes are extended toward the rear of the vehicle;
The rear ends of these openings are communicated with the exhaust gas collection chamber, and the front exhaust pipe and the portion of the rear exhaust pipe that is closer to the engine than the telescopic flexible pipe are connected, and the relative displacement in the longitudinal direction of the vehicle between the front exhaust pipe and the rear exhaust pipe is controlled The reason for this is that they are connected via a stay that allows for but restricts relative displacement in the vertical direction.

An embodiment of the present invention will be described below with reference to FIGS. 1 to 3.

The V-type multi-cylinder engine E includes a front engine block 1 that slopes toward the front of the vehicle, a rear engine block 2 that slopes toward the rear of the vehicle, and a crank that connects these engine blocks 1 and 2 together. Case 3 is provided. The front engine block 1 includes a front cylinder block 4, a front cylinder head 5 coupled to the upper surface of the front cylinder block 4, and a front head cover 6 attached to the upper surface of the front cylinder block 4. It has a rear cylinder block 7, a rear cylinder head 8 integrally connected to its upper surface, and a rear head cover 9 attached to its upper surface.

Pistons 10 ₁ and 10 _{2 are slidably fitted into the cylinder bores of the front and rear cylinder blocks 1 and 2 ,} respectively.
0 ₂ is connected to the crankshaft 12 via connecting rods 11 ₁ and 11 ₂ . The crankshaft 12 is rotatably supported by the crankcase 3 orthogonal to the longitudinal direction of the vehicle.

The front end of a front exhaust pipe 14 is connected to a front exhaust manifold 13 which is fixed to an exhaust port opened on the front surface of the front engine block 1, and a front end of a front exhaust pipe 14 is connected to an exhaust port fixed to an exhaust port opened on the rear surface of the rear engine block 2. A front end of a rear exhaust pipe 16 is connected to the rear exhaust manifold 15. The front exhaust pipe 14 extends downward from the front surface of the engine E and then extends to the rear thereof, and the rear exhaust pipe 16 extends downward from the rear surface of the engine E and then extends to the rear thereof.
A part of the rear exhaust pipe 16, that is, the rear end thereof, is constituted by an extensible and retractable flexible pipe 17 such as a bellows pipe. The open rear ends of the front and rear exhaust pipes 14 and 16 communicate with the inlet of an exhaust gas collection chamber 18, and the outlet of the chamber 18 communicates with a flexible main exhaust pipe 19. The main exhaust pipe 19 communicates with a catalytic converter and an exhaust muffler (not shown).

At the horizontal portion 14a of the front exhaust pipe 14 and the portion of the rear exhaust pipe 16 closer to the engine E than the telescopic flexible tube 17, that is, the substantially vertical portion 16a, both ends of stays 20 made of vertically long plates are provided. The parts 14a and 16a are welded to each other and connected to each other via the stay 20. Since the stay 20 is formed of a plate that is long in the vertical direction, its rigidity is relatively low in the front-rear direction (the direction hh in FIG. 1), but it is stiff in the vertical direction (the direction v-v in FIG. 1). is formed to have relatively high rigidity, and therefore the stay 2
0 indicates the portion 14 of the front and rear exhaust pipes 14 and 16.
Although relative displacement in the longitudinal direction between a and 16a is allowed, relative displacement in the vertical direction is restricted, so external forces in the vertical direction such as engine operating vibrations and vehicle running vibrations are absorbed by the front and rear exhaust pipes 14 and 16. can be dispersed into

Next, the operation of the above embodiment will be explained.

When the engine E is operated, exhaust gas is discharged from the front and rear engine blocks 1 and 2 through the front and rear exhaust manifolds 13 and 15, and the front and rear exhaust pipes 1.
After passing through 4 and 16 and gathering at the exhaust collection room 18,
It flows into the main exhaust pipe 19.

By the way, because the front and rear engine blocks 1 and 2 are arranged in the longitudinal direction of the vehicle, the length and arrangement of the front exhaust pipe 14 and the rear exhaust pipe 16 are different. Although there is a large difference in the amount of thermal expansion in the front and rear directions, the thermal strain that occurs in the front and rear exhaust pipes 14 and 16 is due to the bending, expansion and contraction of the expandable flexible tube 17 that forms part of the rear exhaust pipe 16. In this case, the stay 20 is connected to the front and rear exhaust pipes 14 and
A relatively large relative displacement in the longitudinal direction based on the difference in the amount of thermal expansion of No. 6 can be easily tolerated. Further, the stay 20 is moved by the front and rear exhaust pipes 14 and 1 due to external forces in the vertical direction such as operational vibrations of the engine E.
6 can be approximately evenly distributed to these pipes 14 and 16, and the stress can be prevented from concentrating on the front exhaust pipe 14 and the telescopic flexible pipe 17.

In the above embodiment, the front and rear engine blocks 1 and 2 are arranged in a V-shape along the longitudinal direction.
Although a case has been described in which the present invention is applied to a type engine, a horizontally opposed type engine may be used in which the front and rear engine blocks 1 and 2 are arranged substantially horizontally in the longitudinal direction.

As is clear from the above embodiments, according to the present invention, the front exhaust pipe is connected to the front exhaust manifold fixed to the front engine block, and a part of the pipe is extendable and retractable to the rear exhaust manifold fixed to the rear engine block. The front and rear exhaust pipes were connected to the rear exhaust pipes formed by flexible pipes, and both the front and rear exhaust pipes were extended toward the rear of the vehicle, and their opening rear ends were connected to the exhaust collection chamber. Due to the large difference in thermal expansion, especially in the longitudinal direction, the thermal strain generated in the front and rear exhaust pipes can be effectively absorbed by the expansion, contraction, and bending of the extensible flexible tube. It is possible to prevent the relative displacement or deformation of the front and rear exhaust pipes due to this.

In addition, a stay is provided between the front exhaust pipe and the rear exhaust pipe that is closer to the engine than the telescopic flexible tube, allowing relative displacement in the longitudinal direction of the vehicle but restricting relative displacement in the vertical direction. Since the front exhaust pipe is connected to the front exhaust pipe where stress is likely to occur, the stress generated due to external forces in the vertical direction such as engine operating vibrations and vehicle running vibrations can be dispersed to the rear exhaust pipe via the stay. Therefore, it is possible to effectively prevent stress from being concentrated on the front exhaust pipe and the telescopic flexible pipe, contributing to improving their durability. Furthermore, the stay can easily tolerate a relatively large relative displacement in the longitudinal direction based on the difference in the amount of thermal expansion between the front and rear exhaust pipes, so the above-mentioned thermal strain absorption effect by the telescopic flexible tube can be absorbed by the stay. There is no risk of being hindered because of this.

[Brief explanation of drawings]

1 to 3 show an embodiment of the present invention,
FIG. 1 is a partially cutaway side view thereof, FIG. 2 is a view taken along the line shown in FIG. 1, and FIG. 3 is a perspective view of the exhaust pipe. E... Engine, 1, 2... Front, rear engine block, 12... Crankshaft, 14, 16... Front, rear exhaust pipe, 17... Telescopic flexible pipe, 18... Exhaust collection chamber,
20...stay.

Claims (1)

[Claims] 1. In a horizontal multi-cylinder engine for a vehicle, in which a front engine block 1 and a rear engine block 2 are arranged along the longitudinal direction of the vehicle, and the crankshaft 12 is arranged in a direction perpendicular to the longitudinal direction of the vehicle. , a front exhaust pipe 14 is connected to the front exhaust manifold 13 fixed to the front engine block 1, and a part of the flexible pipe 1 is connected to the rear exhaust manifold 15 fixed to the rear engine block 2.
7, the front and rear exhaust pipes 14 and 16 are both extended toward the rear of the vehicle, and their open rear ends communicate with the exhaust gas collection chamber 18. Part exhaust pipe 14
and a portion of the rear exhaust pipe 16 closer to the engine E than the telescopic flexible pipe 17 via a stay 20 that allows relative displacement in the longitudinal direction of the vehicle but restricts relative displacement in the vertical direction. 1. An exhaust pipe device for a vehicle engine, characterized in that the exhaust pipe device is connected to the exhaust pipe device.