JPS60132018A - Multicylinder engine exhaust device - Google Patents

Abstract

PURPOSE:To prevent the generation of a trough in output by dividing the exhaust manifold of a multicylinder engine and half-way the inside of an exhaust pipe on its lower course, into two parts in such a way that exhaust gas from cylinders, which are mutually close in the firing order, may be collected together. CONSTITUTION:Exhaust pipes 10, which are introduced out of each cylinder of a multicylinder engine, are connected to a manifold 11 in a condition of 10a, 10b, 10c, 10d as shown in the figure, in accordance with the firing order of the cylinders. A partition plate 13a is provided inside the manifold 11. Also, a partition plate 13b is provided inside an exhaust pipe 12, which is provided on the rear side of the manifold 11. Exhaust gas is discharged from the exhaust pipes 10, in the order of 10a, 10b, 10c, and 10d, into the manifold 11, and exhausted outward through the exhaust pipe 12 and a muffler. Thereby, the characteristics of output can be improved due to the streamlining action and the regulation of the pulsation of exhaust by means of the partition plates 13a, 13b, preventing the generation of a trough in output.

Description

[Detailed description of the invention] a. Industrial application field The present invention relates to an exhaust system for a multi-cylinder engine.

2. Description of the Related Art Motorcycles and the like equipped with multi-cylinder engines use exhaust devices that collect exhaust gas discharged from each cylinder into a single exhaust pipe.

The present invention relates to an exhaust system used in such motorcycles and the like.

b. Prior Art FIG. 1 shows an exhaust system for a motorcycle equipped with a four-cylinder engine, which has been commonly used in the past.

In such a motorcycle equipped with a multi-cylinder engine 1 having four or more cylinders, when the exhaust gas emitted from each cylinder is collected into one exhaust pipe and exhausted, the exhaust pipe 2 led out from each cylinder is is connected to an exhaust manifold 3 due to layout considerations, and is exhausted via a muffler 4. Therefore, the exhaust pipes 2 are connected to the exhaust manifold 3 in the order of 2a-2b-2c-2d according to the arrangement of the cylinders. However, the actual firing order of the cylinders is not done in this order, so
Exhaust gases were to be exhausted while interfering with each other.

Therefore, the exhaust pipe 2a led out from each cylinder
2d are collected in the exhaust manifold 3 as shown in FIG. 3 according to the cylinder explosion order to prevent mutual interference of exhaust gases. However, when the exhaust pipes 2a, . . . , 2d are assembled in this order, there is a drawback that, in a medium speed range, a valley in the output is likely to occur due to exhaust pulsation, impairing the riding feeling.

C0 OBJECTS OF THE INVENTION It is an object of the present invention to provide an exhaust system for a multi-cylinder engine that solves the drawbacks of the above-mentioned prior art and can improve the output direction of the medium speed range.

d1 Structure of the Invention Hereinafter, the present invention will be described in detail with reference to the illustrated embodiments.

4 and 5, 10 is a multi-cylinder engine (
(not shown), these exhaust pipes 10 are arranged according to the cylinder explosion order, and the exhaust manifold 11
It is connected to the. 10a -10b -10d -1
0c indicates the firing order K of the cylinders, and thus indicates the state in which the exhaust pipe 10 is connected to the exhaust manifold 11. This exhaust manifold 11 and an exhaust pipe 12 provided on the rear side of this exhaust manifold 11
Partition plates 13a and 13b are provided in a part of the cylinder in the exhaust gas flow direction (axial direction) K, and collect exhaust gases from cylinders having a similar explosion order. The partition plates 13a and 13b are provided inside the exhaust manifold 11 and inside the connecting pipe 12a inserted into the rear side of the exhaust manifold 11. 14 is the exhaust pipe 12
This is a muffler installed at the rear end of the

08 Effect According to the configuration of the present invention described above, exhaust gas flows from the exhaust pipe 10 to the exhaust manifold 11 in the order of cylinder explosions 10a → 10b → 10d → 10C.
discharged inside. And Ex-1st manifold 1
The exhaust gas collected in the exhaust pipe 12 and the muffler 1
It is exhausted to the outside through 4. At this time, the characteristics of the output PS with respect to the rotational speed rpm are improved by the rectification effect and matching of exhaust pulsation by the partition plates 13a and 13b, and as shown in FIG.
Compared to the case without a and 13b, it appears as shown in ■, and the occurrence of the valley α in the output can be prevented.

f6 Effects of the Invention As described above, according to the present invention, the exhaust manifold that collects the exhaust pipes led out from each cylinder and the inside of the exhaust pipe from the exhaust manifold to the middle of the exhaust pipe on the downstream side are Since the exhaust pipe is divided into two parts in the flow direction of the exhaust gas so as to collect the exhaust gases of the cylinders together, the length of the exhaust pipe has been substantially extended, which prevents the occurrence of output valleys and improves performance in the medium speed range. You can aim for the direction of exit.

[Brief explanation of drawings]

Figures 1 to 3 show exhaust systems for conventional multi-cylinder engines, and Figure 1 is a conceptual diagram showing an exhaust system for a multi-cylinder engine mounted on a motorcycle.
3 and 3 are cross-sectional views showing the assembled state of the exhaust pipes. FIG. 4 is a conceptual diagram showing an exhaust system for a multi-cylinder engine according to an embodiment of the present invention, FIG. 5 is a conceptual diagram showing an enlarged part of FIG. 4, and FIG. 7 is a sectional view taken along the line B--B in FIG. 5, and FIG. 8 is a characteristic diagram showing the output characteristics of a multi-cylinder engine equipped with the exhaust system of the present invention. 10... Exhaust pipe, 11...
-Exhaust manifold, 12...exhaust pipe, 13a, 13b...partition plate, 12a...connecting pipe. Flute A M Figure 5 Figure 6 Figure 7 Figure S pm

Claims (1)

[Claims] (11 In an exhaust system that collects and exhausts exhaust gas from a multi-cylinder engine into one exhaust pipe, an exhaust manifold collects exhaust pipes led out from each cylinder, and an exhaust pipe downstream from the exhaust manifold. An exhaust system for a multi-cylinder engine, characterized in that the interior up to the middle of the engine is divided into two parts in the flow direction of exhaust gas so as to collect exhaust gases from cylinders having a similar explosion order.