JPH0598961A - Exhaust device for vehicle - Google Patents

Abstract

PURPOSE:To obtain satisfactory muffler effect and increase freeness of design by providing a catalyst case which holds catalyzer, and arranging it in a lower space of a muffler. CONSTITUTION:A catalyst case 20 holding a catalyzer is provided on the way of an exhaust pipe 18 of an engine 4. A muffler 22 is connected to a downstream side of the exhaust pipe 18, and a tail pipe 24-1 is connected thereto. The muffler 22 is installed on a lower part of a vehicle body 2a, while the catalyst case 20 is arranged on a lower space S of the muffler 22. Muffler performance is improved and freeness of design is increased by providing sufficient length of exhaust pipe.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust system for a vehicle, and more particularly to a vehicle having an exhaust gas purifying catalyzer and a muffler muffler in the exhaust system of the engine when the engine is mounted on the vehicle. Regarding exhaust system.

[0002]

2. Description of the Related Art In an exhaust system for an engine mounted on a vehicle, the pipeline length of the exhaust manifold is required to be small in design, and generally, an exhaust manifold having a collecting portion near the exhaust port of each cylinder is used. Is used.

Further, if the diameter of the exhaust pipe of the exhaust device is made small or the length of the exhaust pipe is made large, the torque in the low / medium speed range can be improved. However, if the diameter of the exhaust pipe is made smaller than necessary, the muffler back pressure will be large, so it cannot be said to be a good measure, and it is impossible to make the length of the exhaust pipe extremely large due to restrictions on the vehicle body. is there.

A catalyzer is provided in the exhaust system of the exhaust system to reduce harmful components in exhaust gas such as CO and HC by a catalytic function.

An exhaust system for a vehicle is disclosed in Japanese Patent Laid-Open No. 2-20.
Some are disclosed in Japanese Patent No. 7123. The exhaust system for a vehicle disclosed in this publication is a midship vehicle in which the engine is mounted near the center of the vehicle body and has two exhaust pipes. Extend, then bend each toward the center of the vehicle width, and further extend from the center of the vehicle width in the left-right direction apart from each other, and install left and right mufflers in front of the extension ends without narrowing the passenger compartment The exhaust pipe length and the muffler capacity are sufficiently secured.

[0006]

In the conventional exhaust system for a vehicle, as shown in FIG. 4, generally, the catalyst case 120 is provided immediately downstream of the unillustrated collecting portion of the exhaust manifold 112 communicating with the engine 104. Are arranged.

Further, in a rear engine vehicle equipped with a rear engine of the vehicle and a midship engine vehicle equipped with an engine in a central portion of the vehicle, there are severe restrictions on the total height of the power train as compared with a front engine vehicle. ..

As a result, when the engine is mounted on the vehicle, the mounting angle (or inclination angle) of the engine is often large, and the catalyst case 120 that holds the catalyzer immediately downstream of the exhaust manifold 112.
However, there is an inconvenience that the installation work is difficult because the installation space is lost, and a great limitation occurs when the carrier case is attached.

Further, since there is no space for installing the catalyst case, it is not possible to secure a sufficient length of the exhaust pipe, and it is not possible to improve the torque particularly in the low / medium speed range, and the silencing performance is also improved. Is reduced, which is disadvantageous in practical use.

[0010]

Therefore, in order to eliminate the above-mentioned inconvenience, the present invention provides an exhaust gas purifying catalyzer in an exhaust pipe of an engine mounted in a vehicle and a muffler for muffling provided in a rear portion of the vehicle. In the exhaust system for a vehicle provided with, a catalyst case for holding the catalyst is provided, and the catalyst case is arranged in a space below the muffler.

[0011]

According to the invention as described above, when the engine is mounted on the vehicle, the catalyst case communicating with the engine is arranged in the lower space of the muffler, and the exhaust pipe is sufficiently long. It has a high degree of freedom in design as well as ensuring excellent muffling performance.

[0012]

Embodiments of the present invention will be described in detail below with reference to the drawings.

1 to 3 show an embodiment of the present invention. 1 to 3, reference numeral 2 is a vehicle, 4 is an engine mounted on the vehicle 2 in a midship shape and is installed horizontally, 6 is a surge tank, 8 is an intake pipe, 10 is an intake manifold, and 12 is an exhaust manifold.

As shown in FIG. 1, the engine 4 is mounted at a position slightly ahead of the drive shaft 14 of the vehicle 2.

Then, the intake manifold 10 is attached to the engine 4.
And an exhaust manifold 12 are mounted respectively, and an oil pan 16 under the engine 4 is provided on the downstream side of the exhaust manifold 12.
An exhaust pipe 18 passing through the part is connected and provided.

A catalyst case 20 for holding a catalyst (not shown) is provided in the middle of the exhaust pipe 18, and a muffler 22 is provided downstream of the exhaust pipe 18 so that the muffler 22 has two tail pipes. 24-1 and 24-2 are connected and provided.

As shown in FIG. 1, the muffler 22 is mounted on the rear portion of the vehicle 2 and below the vehicle body 2a.
The catalyst case 20 is arranged in the lower space S of FIG.

More specifically, the lower space S of the muffler 22
When the catalyst case 20 is disposed in the exhaust pipe 18, as shown in FIG. 1, the exhaust pipe 18 is curved to a position higher than the drive shaft 14 after passing under the drive shaft 14, and the downstream side is connected to the catalyst case 20. Is done.

Next, the operation will be described.

When the engine 4 operates, the engine 4
The exhaust gas after combustion is discharged from. The exhaust gas sequentially passes through the exhaust manifold 12 and the exhaust pipe 18 and reaches the catalyst case 20, and a catalyzer (not shown) in the catalyst case 20 reduces harmful components in the exhaust gas such as CO and HC.

Then, the exhaust gas reaches the muffler 22, and from the muffler 22, two tail pipes 24-1 and 24- are provided.
After passing through 2, it is discharged to the rear of the vehicle 2.

As a result, when the engine 4 is mounted on the vehicle 2 in a midship-like manner and placed horizontally, the catalyst case 20 communicating with the engine 4 has a space S below the muffler 22, which has conventionally been a dead space. In addition, the exhaust pipe 18 can be provided with a sufficient length, good sound deadening performance can be ensured, the degree of freedom in design is increased, and it is practically advantageous, and space efficiency is improved. It is possible to contribute to the improvement of performance.

Further, when the catalyst case 20 is arranged in the lower space S of the muffler 22, there is no fear that the number of parts will increase as compared with the conventional case, so that the cost can be kept low, Economically advantageous.

[0024]

As described in detail above, according to the present invention, the exhaust gas for vehicles is provided with the exhaust gas purifying catalyzer and the muffler for muffler arranged at the rear of the vehicle in the exhaust pipe of the engine mounted on the vehicle. Since the catalyst case for holding the catalyst of the device is provided and the catalyst case is arranged in the lower space of the muffler, when the engine is mounted on the vehicle, the catalyst case for contacting the engine is used as the conventional dead space. It can be placed in the lower space of the muffler, the length of the exhaust pipe can be sufficiently secured, good sound deadening performance can be secured, and the degree of freedom in design is large, which is practically advantageous. Moreover, space efficiency can be improved, which can contribute to improved performance. Further, when the catalyst case is arranged in the lower space of the muffler, there is no fear that the number of parts will increase as compared with the conventional case, so that the cost can be kept low, which is economically advantageous.

[Brief description of drawings]

FIG. 1 is a schematic enlarged view of an engine mounted on a rear portion of a vehicle showing an embodiment of the present invention.

FIG. 2 is a front view of a vehicle exhaust device.

FIG. 3 is a plan view of a vehicle exhaust device.

FIG. 4 is a schematic explanatory view of a vehicle exhaust system showing a conventional technique of the present invention.

[Explanation of symbols]

 2 vehicle 4 engine 8 intake pipe 10 intake manifold 12 exhaust manifold 14 drive shaft 18 exhaust pipe 20 catalyst case 22 muffler 24-1, 24-2 tail pipe

Claims (1)

[Claims] 1. An exhaust system for a vehicle, wherein an exhaust pipe for an engine mounted on a vehicle is provided with a catalyst for purifying exhaust gas and a muffler for muffler arranged at a rear portion of the vehicle, and a catalyst case for holding the catalyst is provided. An exhaust system for a vehicle, wherein the catalyst case is provided in a space below the muffler.