JP4478096B2 - Motorcycle exhaust system - Google Patents

Description

  The present invention relates to an exhaust device for a motorcycle that is particularly suitable for application to a motorcycle equipped with a horizontally-placed V-type engine.

  FIG. 8 is a side view of a motorcycle provided with an example of a conventional motorcycle exhaust device.

  In recent years, in this type of motorcycle, the capacity of exhaust silencers tends to increase due to the increasing importance of environmental considerations. For this reason, there is a demand for improving the space efficiency as much as possible even in the exhaust device disposed under the engine.

Therefore, conventionally, as shown in FIG. 8, in order to increase the space efficiency of the exhaust device 5, two expansion chambers, that is, a front expansion chamber 27 and a rear expansion chamber 26 are provided in front of and behind the oil pan 15 protruding below the engine 19. , And a technique for connecting the front expansion chamber 27 and the rear expansion chamber 26 with a connecting pipe 28 (hereinafter, referred to as known technique 1) has been proposed (for example, see Patent Document 1).
JP 2004-26007 A (paragraph [0015] column, FIG. 2)

  However, this known technique 1 has the following problems.

  First, since the connecting pipe 28 is provided below the oil pan 15, there is a limitation when the capacity of the oil pan 15 is increased.

  Second, a catalyst device may be placed in the expansion chamber. In this case, it is necessary to consider the arrangement of the catalyst device from the viewpoint of improving space efficiency.

  An object of the present invention is to provide an exhaust device for a motorcycle that can solve these problems.

First, in the invention of the exhaust system for a motorcycle according to claim 1, the front expansion chamber and the rear expansion chamber are arranged before and after the downward projecting portion of the engine, and the front expansion chamber and the rear expansion chamber are connected to each other by a connecting pipe. In addition, in the exhaust system for a motorcycle, the connecting pipe is offset on either the left or right side of the vehicle body, and the front expansion chamber and the rear expansion chamber are arranged by being distributed forward and backward, and the side of the space by disposing the connecting tube, the space formed by being surrounded by them, that it has placed so as to overlap the connecting pipe as viewed from the side bulging downward projecting portion of the engine downward Features.
In the motorcycle exhaust apparatus according to claim 2, the rear expansion chamber is on the exhaust upstream side, the front expansion chamber is on the exhaust downstream side, and a discharge pipe is provided in the front expansion chamber. It is characterized by being.
In the invention of the exhaust device for a motorcycle according to claim 3, the rear expansion chamber is provided with a catalyst device, and an exhaust pipe connected to the engine opens to face the catalyst device. A bent portion that is connected to a tube and is bent toward the inside of the U-shaped tube is formed in the outer peripheral portion of the U-shaped tube in the vicinity of the connection portion between the U-shaped tube and the rear expansion chamber. To do.
Further, in the invention of the exhaust system for a motorcycle according to claim 4, the front expansion chamber bulges to a position below a radiator disposed in front of the engine .
Also, in the invention of the exhaust system of a motorcycle according to claim 5, wherein the connecting pipe is a vertical oval cross-sectional shape that rises upwardly take a wide range from the top portion bottom, and the bottom portion is directed from the center outward It is characterized by that.

  According to the present invention, a front expansion chamber and a rear expansion chamber are disposed before and after a downward projecting portion (oil pan or the like) of an engine, and the front expansion chamber and the rear expansion chamber are connected to each other by a connecting pipe. In the exhaust device, the connecting pipe is formed by being displaced on either the left or right side of the vehicle body, arranging the front expansion chamber and the rear expansion chamber on the front and rear sides, and arranging the connecting pipe on the side. Since the lower projecting portion of the engine can be swelled downward in the space, it is possible to further increase the space efficiency of the exhaust device while sufficiently securing the capacity of the lower projecting portion of the engine.

  Further, when the rear expansion chamber is the exhaust upstream side, the front expansion chamber is the exhaust downstream side, and the exhaust pipe is provided in the front expansion chamber, heat propagation to the running engine is suppressed.

  In addition, a catalyst device is provided in the rear expansion chamber, and an exhaust pipe is connected to the engine so as to open facing the catalyst device via the U-shaped tube, in the vicinity of the connection portion between the U-shaped tube and the rear expansion chamber, When a bent portion that is bent inward is formed on the outer peripheral portion of the U-shaped tube, the exhaust gas flowing from the U-shaped tube to the rear expansion chamber is evenly diffused to the catalyst device in the rear expansion chamber, thereby improving the purification efficiency.

  Further, when the front expansion chamber bulges to the lower side of the radiator disposed in front of the engine, the capacity of the front expansion chamber can be increased while minimizing the influence on the cooling performance of the radiator.

  In addition, in a motorcycle exhaust system in which a front expansion chamber and a rear expansion chamber are disposed before and after the downward projecting portion of the engine, and the front expansion chamber and the rear expansion chamber are connected to each other by a connecting pipe, a catalyst is provided in the rear expansion chamber. Since the apparatus is provided, even if the capacity increases due to the introduction of the catalyst apparatus, the capacity used for noise reduction can be earned in the front expansion chamber which is relatively easy to take capacity. As a result, it becomes easy to achieve both exhaust purification and noise reduction.

  Furthermore, if the bottom of the connecting pipe is wider than the top and has a vertically long oval cross-sectional shape that rises upward from the center toward the outside, the capacity of the downward projecting portion of the engine can be efficiently secured, and In addition, the cross-sectional area of the connecting pipe can be secured while preventing the bank angle of the motorcycle from being limited as much as possible.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

<First Embodiment>
FIG. 1 is a side view of a motorcycle provided with a first embodiment of a motorcycle exhaust system according to the present invention, FIG. 2 is a side view showing an engine periphery of the motorcycle shown in FIG. 1, and FIG. FIG. 4 is a plan view showing a first embodiment of a motorcycle exhaust apparatus according to the present invention, and FIG. 5 is a plan view of the motorcycle shown in FIG. It is sectional drawing by the VV line of an exhaust apparatus.

  As shown in FIG. 1, the motorcycle 1 includes a pair of left and right main frames 2 extending obliquely downward and rearward from the head pipe 4, and a front fork 3 is pivotally connected to the head pipe 4. . A handle 16 is attached to the upper end of the front fork 3. On the other hand, a front wheel 6 is rotatably supported at a lower end portion of the front fork 3, and a front fender 8 is attached above the front wheel 6 in a form supported by the front fork 3. Further, an annular front brake disc 10 is fixed to the left side of the front wheel 6, and a front brake caliper 11 is attached to the front brake disc 10 so as to be supported by the front fork 3.

  Further, as shown in FIG. 1, a cowl 7 is attached to the main frame 2 so as to cover the front of the vehicle body, and a headlight 12 and a pair of left and right rearview mirrors 13 are attached to the cowl 7. . Further, a fuel tank 21 is placed on the main frame 2, and a seat 22 is detachably attached to the rear of the fuel tank 21.

  Further, as shown in FIG. 1, a swing arm (rear fork) 23 is swingably supported at the lower rear portion of the main frame 2, and a rear wheel 25 rotates at the rear end portion of the swing arm 23. It is supported freely. A rear cushion 40 is bridged between the main frame 2 and the swing arm 23.

  Further, as shown in FIG. 1, a rear fender 32 is attached to the upper rear portion of the main frame 2 so as to be positioned above the rear wheel 25, and a stop lamp 33 is attached to the rear fender 42.

  By the way, as shown in FIG. 1, a horizontal V-type 4-cylinder engine 19 in which a front two-cylinder cylinder 17 and a rear two-cylinder cylinder 18 intersect each other in a V-type is mounted at the center of the main frame 2. ing. As shown in FIG. 2, a radiator 20 is installed in front of the engine 19. Below the engine 19, an oil pan 15 projects downward. An exhaust device 5 is disposed in the vicinity of the oil pan 15. The exhaust device 5 includes exhaust pipes 34 and 35, a U-shaped pipe 36, a C-shaped pipe 37, a rear expansion chamber 26, a connecting pipe 28, and a front side. An expansion chamber 27, a discharge pipe (tail pipe) 31, and the like are included.

  That is, as shown in FIGS. 3 and 4, a rear expansion chamber 26 is disposed behind the oil pan 15, and a front expansion chamber 27 is disposed in front of the oil pan 15. A connecting pipe 28 is connected between the rear expansion chamber 26 and the front expansion chamber 27 so as to be offset from the right side of the vehicle body. The oil pan 15 is connected to the front expansion chamber 27, the rear expansion chamber 26, and the connection pipe. 28 is located in a space formed by being surrounded by. Here, the oil pan 15 is swelled downward in a space formed by arranging the front expansion chamber 27 and the rear expansion chamber 26 in the front and rear directions and the connecting pipe 28 on the side. As shown in FIG. 5, the connecting pipe 28 has a vertically long oval cross-sectional shape in which the bottom portion 28a is wider than the top portion 28b and the bottom portion 28a rises upward from the center toward the outside.

  Here, as shown in FIGS. 3 and 4, a catalyst device 38 is arranged in the rear expansion chamber 26. The front expansion chamber 27 is composed of a first chamber 29 and a second chamber 30, and the first chamber 29 and the second chamber 30 communicate with each other via a communication cylinder 24. A connecting pipe 28 communicates with the first chamber 29, and a discharge pipe 31 is connected to the second chamber 30 toward the rear of the vehicle body as shown in FIG. As shown in FIG. 2, the second chamber 30 swells to the lower side of the radiator 20, and an inclined portion 30 a that matches the lower end portion of the radiator 20 is formed on the upper surface of the second chamber 30. .

  Further, as shown in FIG. 2, exhaust pipes 34 are respectively attached downward to the cylinder heads of the cylinders 17 of the front two cylinders, and these exhaust pipes 34 merge below the engine 19 to form a U-shape. The pipe 36 is connected to the rear expansion chamber 26. As shown in FIG. 4, a bent portion 39 that is bent inward is formed in the outer peripheral portion of the U-shaped tube 36 in the vicinity of the connection portion between the U-shaped tube 36 and the rear expansion chamber 26. On the other hand, as shown in FIG. 2, exhaust pipes 35 are respectively attached downward to the cylinder heads of the cylinders 18 of the rear two cylinders, and these exhaust pipes 35 are joined at the rear of the engine 19 to form a C-shape. It is connected to the rear expansion chamber 26 via a pipe 37. Therefore, the rear expansion chamber 26 is on the exhaust upstream side, and the front expansion chamber 27 is on the exhaust downstream side.

  In the motorcycle 1 having such a configuration, since the connecting pipe 28 is located on the side of the oil pan 15, the space efficiency of the exhaust device 5 can be further increased.

  The rear expansion chamber 26 is located on the upstream side of the exhaust gas at a relatively high temperature. However, since the rear expansion chamber 26 is disposed behind the engine 19, heat propagation to the running engine 19 is suppressed.

  Further, since the catalyst device 38 is disposed in the rear expansion chamber 26, even if the capacity increases due to the entry of the catalyst device 38, the catalyst device 38 is used for noise reduction in the front expansion chamber that is relatively easy to take up the capacity. You can earn capacity. As a result, it becomes easy to achieve both exhaust purification and noise reduction. In addition, a bent portion 39 that is bent inward is formed in the outer peripheral portion of the U-shaped tube 36 in the vicinity of the connection portion between the U-shaped tube 36 and the rear expanded chamber 26. Exhaust gas flowing to 26 is evenly diffused to the catalyst device 38 in the rear expansion chamber 26, and purification efficiency is increased. Furthermore, since the catalyst device 38 is disposed behind the engine 19, heat generated in the catalyst device 38 during traveling is less likely to be transmitted to the engine 19 as compared with the case where the catalyst device 38 is disposed in front of the engine 19.

  On the other hand, the front expansion chamber 27 is a relatively low-temperature exhaust downstream side, and since the front expansion chamber 27 swells to the lower side of the radiator 20, the front expansion chamber 27 is expanded forward while minimizing the influence on the cooling performance of the radiator 20. The capacity of the chamber 27 can be increased. Moreover, since the upper surface of the front expansion chamber 27 is inclined in accordance with the lower end portion of the radiator 20, the capacity of the front expansion chamber 27 can be increased efficiently by being spaced apart from the radiator 20 evenly.

  The connecting pipe 28 that connects the rear expansion chamber 26 and the front expansion chamber 27 has a vertically long oval cross-sectional shape in which the bottom portion 28a is wider than the top portion 28b and the bottom portion 28a rises upward from the center toward the outside. Therefore, the capacity of the oil pan 15 can be efficiently secured, and the cross-sectional area of the connecting pipe 28 can be secured while preventing the bank angle of the motorcycle 1 from being limited as much as possible.

<Second Embodiment>
FIG. 6 is a side view showing the periphery of an engine of a motorcycle equipped with a second embodiment of the exhaust system for a motorcycle according to the present invention, and FIG. 7 shows a second embodiment of the exhaust system for a motorcycle according to the present invention. FIG.

  In the first embodiment described above, the motorcycle 1 on which the horizontally-placed V-type four-cylinder engine 19 is mounted has been described. However, as shown in FIGS. The present invention can also be similarly applied to the motorcycle 1 equipped with a horizontally mounted V-type 5-cylinder engine 19 in which the cylinder 18 intersects the V-type. In this case, as shown in FIG. 6, three exhaust pipes 34 are attached to the cylinder 17 of the front three cylinders, and these exhaust pipes 34 are connected to the rear expansion chamber 26 as shown in FIG. Since the U-shaped tube 36 has the same configuration as that of the first embodiment except that the diameter of the U-shaped tube 36 is increased in accordance with the displacement, the above-described effects can be obtained.

<Other embodiments>
In the above-described embodiment, the motorcycle 1 on which the horizontal V-type engine 19 is mounted has been described. However, the engine 19 of a type other than the horizontal V-type (for example, vertical V-type, parallel multi-cylinder, etc.) is used. The present invention can be similarly applied to the mounted motorcycle 1.

  In the above-described embodiment, as shown in FIG. 4, a case where the connecting pipe 28 connecting the front expansion chamber 27 and the rear expansion chamber 26 disposed before and after the oil pan 15 is offset to the right side of the vehicle body. Although described, the connecting pipe 28 may be offset from the left side of the vehicle body. In short, if the connecting pipe 28 is offset on either the left or right side of the vehicle body, the above-described effects can be obtained.

  In the above-described embodiment, the motorcycle 1 in which the oil pan 5 protrudes downward from the engine 19 has been described. However, the downward protrusion is not limited to the oil pan 5. For example, the present invention can be similarly applied when a case portion of an auxiliary machine such as a pump projects below the engine 19.

  The present invention can be widely applied to motorcycles equipped with various types of engines such as a horizontal V-type engine.

1 is a side view of a motorcycle provided with a first embodiment of a motorcycle exhaust device according to the present invention. FIG. 2 is a side view showing an engine periphery of the motorcycle shown in FIG. 1. 1 is a side view showing a first embodiment of an exhaust device for a motorcycle according to the present invention. 1 is a plan view showing a first embodiment of an exhaust device for a motorcycle according to the present invention. Fig. 5 is a cross-sectional view taken along line VV of the exhaust device for the motorcycle shown in Fig. 4. FIG. 6 is a side view showing an engine periphery of a motorcycle including a second embodiment of the motorcycle exhaust device according to the present invention. FIG. 3 is a plan view showing a second embodiment of the exhaust device for a motorcycle according to the present invention. FIG. 6 is a side view of a motorcycle including an example of a conventional motorcycle exhaust device.

Explanation of symbols

1 …… Motorcycle 2 …… Main frame 5 …… Exhaust device 15 …… Oil pan (downward protruding part)
19 …… Engine 20 …… Radiator 26 …… Back expansion chamber 27 …… Front expansion chamber 28 …… Connecting pipe 31 …… Discharge pipe 34, 35 …… Exhaust pipe 36 …… U-shaped pipe 38 …… Catalyst device 39 ... ... Bent part

Claims (5)

In the exhaust device for a motorcycle, the front expansion chamber and the rear expansion chamber are arranged before and after the downward projecting portion of the engine, and the front expansion chamber and the rear expansion chamber are connected to each other by a connecting pipe.
The connecting pipe is offset to either the left or right side of the vehicle body,
Distributes the front and rear placing the rear expansion chamber and the front expansion chamber, also, by arranging the connecting pipe on the side of the space, the space formed by being surrounded by them, of the engine characterized by being placed so as to overlap the connecting pipe in a side view bulged downward projecting portion downward, motorcycle exhaust system. The rear expansion chamber is on the exhaust upstream side, and the front expansion chamber is on the exhaust downstream side,
The exhaust device for a motorcycle according to claim 1, wherein a discharge pipe is provided in the front expansion chamber. The rear expansion chamber is provided with a catalyst device,
An exhaust pipe connected to the engine is connected to a U-shaped pipe opening facing the catalyst device;
3. A bent portion that bends inward of the U-shaped tube is formed in an outer peripheral portion of the U-shaped tube in the vicinity of a connection portion between the U-shaped tube and the rear expansion chamber. The exhaust system for a motorcycle according to claim 1.   The exhaust device for a motorcycle according to claim 2, wherein the front expansion chamber bulges to a lower side of a radiator disposed in front of the engine. The connecting pipe is characterized in that the bottom is elongated oval cross-sectional shape that rises upwardly take a wide range from the top, and bottom direction from the center outward, according to any one of claims 1 to 4 Motorcycle exhaust system.

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