JP5083527B2 - Motorcycle exhaust system - Google Patents

Description

  The present invention relates to an exhaust device for a motorcycle in which an exhaust gas sensor is attached to an exhaust pipe.

  In a motorcycle that employs a fuel injection system as an air-fuel mixture supply system to the engine, the exhaust gas sensor detects the oxygen concentration in the exhaust gas, and feedback controls the fuel injection amount from the injector based on the detected oxygen concentration. Thus, an air-fuel mixture having a desired air-fuel ratio (A / F) is formed.

  By the way, various proposals have been made so far regarding the mounting position of the exhaust gas sensor. For example, Patent Document 1 discloses an exhaust muffler of a motorcycle in which an exhaust gas sensor is provided at an intermediate portion of the exhaust pipe. A configuration has been proposed in which an exhaust gas sensor is inclined to the outside in the vehicle width direction at a connection flange portion that is split into two parts and a rear half part so as to be separable at the split part.

Patent Document 2 proposes an arrangement structure of an exhaust gas sensor in an underbone type motorcycle. The exhaust gas sensor is arranged in front of the right protruding portion of the crankcase and at an outer position than the right side surface of the cylinder block. A configuration in which an exhaust gas sensor is attached to the upper side wall of the pipe has been proposed.
JP 2007-085235 A JP 2000-335467 A

  By the way, in an underbone type motorcycle, since a footrest, a rear brake pedal, etc. are arrange | positioned at the side of a crankcase, the arrangement space of an exhaust gas sensor cannot be ensured at the side of a crankcase. In the configuration proposed in Patent Document 1, even if an exhaust gas sensor is arranged to avoid interference with a footrest, a rear brake pedal and the like arranged on the side of the crankcase in an underbone type motorcycle, the rear brake pedal is not used. There is a possibility that the exhaust gas sensor contacts the sole of the rider's right foot.

  Further, in a motorcycle, if the exhaust pipe is bent at a substantially right angle on the side of the cylinder block, the exhaust resistance increases. Therefore, the handling of the exhaust pipe as described in Patent Document 2 cannot be employed. In addition, since a vehicle body cover such as a leg shield is located on the side of the cylinder block, if the exhaust pipe is disposed so as to protrude outward in the vehicle width direction with respect to the side surface of the cylinder block, the vehicle body cover is widened. This is not preferable because air resistance increases.

  Therefore, in reality, the exhaust pipe is inclined and arranged so as to bulge outward in the vehicle width direction from the front to the rear. However, the exhaust pipe arranged in this way is patented. It is not possible to ensure a sufficient space for arranging the exhaust gas sensor in the space specified in Document 2. Further, the configuration proposed in Patent Document 2 has a problem that the maintainability of the user is deteriorated because the exhaust gas sensor is attached at a position close to the engine.

  The present invention has been made in view of the above problems, and its object is to effectively protect the exhaust gas sensor and to improve the detection accuracy by suppressing the temperature rise of the exhaust gas sensor. An object of the present invention is to provide an exhaust device for a motorcycle.

In order to achieve the above object, according to the first aspect of the present invention, an engine crankcase disposed below a main frame constituting a vehicle body frame is suspended from the main frame, and from the crankcase toward the front of the vehicle body. An exhaust pipe is attached to the extending cylinder head, the exhaust pipe is offset from the lower surface of the cylinder head toward one side of the crankcase and extends to the rear of the vehicle body, and a muffler is connected to the rear end of the exhaust pipe. In the exhaust system of a motorcycle,
A swing of a kick starter lever pivotally supported by a swinging shaft that protrudes outward from the bulging portion of the crankcase between the crankcase of the exhaust pipe and a vehicle body part facing the crankcase in a side view. Install the exhaust gas sensor tilted inward in the vehicle width direction with respect to the vertical line behind and below the vehicle axis ,
The upper portion of the exhaust gas sensor is positioned between the bulging portion of the crankcase and a vehicle body part that faces the bulging portion in a side view, and the swing range and weight within the swing surface of the kick starter lever. It is characterized by tilting to a position where it does not become .

According to a second aspect of the present invention, in the first aspect of the present invention, the bulging portion of the crankcase is a clutch cover.

According to a third aspect of the present invention, in the first or second aspect of the invention, the vehicle body part is a muffler bracket for attaching the muffler to a vehicle body frame.

The invention according to claim 4 is the invention according to any one of claims 1 to 3 , wherein the exhaust pipe is divided into two parts, and the exhaust gas sensor is attached in the vicinity immediately upstream of the connecting portion.

The invention according to claim 5 is the invention according to any one of claims 1 to 4 , characterized in that an intermediate part in the longitudinal direction of a sensor harness extending from an upper part of the exhaust gas sensor is attached to the vehicle body frame. To do.

  According to the first aspect of the present invention, since the exhaust gas sensor is attached between the crankcase of the exhaust pipe and the vehicle body part facing the crankcase in a side view, the exhaust gas sensor is also laterally upward with respect to the exhaust pipe. And the exhaust gas sensor can be effectively protected from flying stones and jumping water. In addition, since a protective plate for protecting the exhaust gas sensor is not required, the exhaust gas sensor is efficiently cooled by the traveling wind, the temperature rise is suppressed, and high detection accuracy is ensured.

Further , since the exhaust gas sensor can be disposed away from the exhaust pipe that is a heat source and the exhaust pipe can be left exposed outward in the vehicle width direction, the temperature of the exhaust pipe and the exhaust gas sensor is increased. Can be suppressed. Since the exhaust pipe is disposed away from the rider, the exhaust pipe is positioned below the crankcase of the engine. The exhaust gas sensor is tilted inward in the vehicle width direction with respect to the vertical line, and the exhaust gas sensor Is positioned between the bulging portion of the crankcase and the vehicle body part that faces the bulging portion in a side view, so that the exhaust gas sensor can be brought close to the bulging portion of the crankcase, and the exhaust gas sensor can be It can protect more effectively.

Further , the exhaust gas sensor is disposed behind and below the swing shaft of the kick starter lever pivotally supported by the swing shaft protruding outward from the bulging portion of the crankcase, and the upper portion of the exhaust gas sensor is disposed on the kick starter lever. Since it is tilted to a position that does not overlap the swing range in the swing surface, the exhaust gas sensor does not interfere with the kick star lever even when the kick starter lever is operated, and damage to the exhaust gas sensor can be prevented. Further, since the sensor harness connected to the upper part of the exhaust gas sensor is located on the inner side in the vehicle width direction than the kick starter lever, the sensor harness does not interfere with the kick starter lever, and the damage is prevented.

According to the second aspect of the present invention, the clutch cover that bulges laterally over the entire length of the crankcase in the longitudinal direction constitutes the bulged portion of the crankcase. Therefore, it is possible to prevent the stones and grooves that the front wheel has flipped up from coming into contact with the exhaust gas sensor, and the exhaust gas sensor is effectively protected.

According to the invention described in claim 3 , since the exhaust gas sensor is mounted between the bulging portion of the crankcase and the muffler bracket facing the bulging portion in a side view, the exhaust gas sensor is connected to the bulging portion of the crankcase. Therefore, the exhaust gas sensor does not interfere with the vehicle body components due to engine vibration or rear wheel bumps, and damage to the exhaust gas sensor is prevented.

According to the fourth aspect of the present invention, the exhaust pipe is divided into two parts, and the exhaust gas sensor is mounted in the vicinity immediately upstream of the connecting portion. And the exhaust gas sensor is prevented from being damaged. In addition, the sensor harness connected to the exhaust gas sensor is not forcibly pulled and disconnected.

According to the fifth aspect of the invention, since the sensor harness extending in the longitudinal direction from the upper part of the exhaust gas sensor is attached to the vehicle body frame, a large vibration of the sensor harness is prevented, and the sensor harness is disconnected or exhausted. The occurrence of troubles such as erroneous detection by the gas sensor can be prevented.

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

  1 is a right side view of a motorcycle equipped with an exhaust device according to the present invention, FIG. 2 is a right side view showing a configuration of the main part of the motorcycle, FIG. 3 is a plan view thereof, and FIG. It is A sectional view.

  A motorcycle 1 shown in FIG. 1 is an underbone type motorcycle, and as shown in FIGS. 2 and 3, a steering shaft (not shown) is rotatable on a head pipe 2 arranged at the front upper part of the vehicle body. Is inserted. As shown in FIG. 1, a steering wheel 3 is attached to the upper end of the steering shaft, a front fork 4 is attached to the lower end of the steering shaft, and a front wheel 5 rotates at the lower end of the front fork 4. It is pivotally supported.

  As shown in FIGS. 2 and 3, a main frame 6 constituting a part of the vehicle body frame extends obliquely downward from the head pipe 2 toward the rear of the vehicle body. A pair of left and right side frames 7 are branched. These side frames 7 rise obliquely upward toward the rear of the vehicle body, and a fuel tank 8 and a seat 9 (see FIG. 1) are supported on the rising portions. Further, as shown in FIG. 2, a storage box 10 is disposed in front of the fuel tank 8.

  Further, as shown in FIG. 2, an engine 11 as a drive source is disposed below the main frame 6, and a crankcase 12 of the engine 11 is suspended from the main frame 6 by engine brackets 13 and 14. ing. Further, in the engine 11, a cylinder portion extends from the crankcase 12 toward the front of the vehicle body, and a cylinder head 15 is disposed at a front portion thereof. An intake pipe 16 connected to an upper portion of the cylinder head 15. A plunger type pump-integrated fuel injection device (injector) 17 and a throttle body 18 are attached. The throttle body 18 is connected to the lower rear surface of an air cleaner 19 attached below the front end of the main frame 6.

  A delivery hose 20 extending from the fuel tank 8 is connected to the fuel injection device 17, and a return hose 21 extending from the fuel injection device 17 is connected to the fuel tank 8. As shown in FIG. 3, a fuel filter 22 is provided in the middle of the delivery hose 20, and a bypass hose 23 extending from the fuel filter 22 is connected to the middle portion of the return hose 21 and connected to the fuel tank 8. doing. Bubbles generated in the fuel injection device 17 are recirculated in the return hose 21 to the fuel tank 8. At this time, fuel containing no bubbles is supplied from a bypass hose 23 connected in the middle of the return hose 21. The fuel flows into the filter 22, bypasses the fuel tank 8, and is supplied to the fuel injection device 17 again.

  On the other hand, an exhaust pipe 24 is connected to the lower part of the cylinder head 15. The exhaust pipe 24 extends downward from the cylinder head 15, and then is gently bent toward the rear of the vehicle body. The muffler 25 is connected to the rear end of the vehicle body. Here, as shown in FIG. 2, the muffler 25 is attached so as not to move relative to the engine 11 by a muffler bracket 26 that is a vehicle body part. The muffler 25 and the engine 11 are only a minute amount relative to the vehicle body. Does not move relative.

  Incidentally, as shown in FIG. 3, a generator cover 27 and a clutch cover 28 that constitute the bulging portion are respectively attached to the left and right ends of the crankcase 12 of the engine 11. Although not shown in the figure, the clutch cover 28 houses an automatic centrifugal clutch provided at the crankshaft end at the front and a multi-plate clutch for shifting at the rear. 28 bulges outward over the entire longitudinal dimension of the crankcase 12.

  A pivot bracket 29 shown in FIG. 4 is attached to the main frame 6 behind the crankcase 12, and a pivot shaft 30 and a cross member 31 are horizontally mounted above and below the pivot bracket 29. The muffler bracket 26 is attached to the right end portions (the left end portion in FIG. 4) of the pivot shaft 30 and the cross member 31 with bolts 32 and 33.

  As shown in FIG. 2, a front end of a swing arm 34 is supported on the pivot shaft 30 so that the swing arm 34 can swing up and down. A rear wheel 35 shown in FIG. It is pivotally supported so that it can rotate. The rear end of the swing arm 34 and the rear wheel 35 are suspended from the vehicle body by a rear cushion 36. Although not shown, an endless drive chain is wound around the drive sprocket attached to the output shaft of the engine 11 and the driven sprocket attached to the rear axle, and the output shaft of the engine 11 is rotated. This is transmitted to the rear wheel 35 via the sprocket and the drive chain, and the rear wheel 35 is rotationally driven to cause the motorcycle 1 to travel. As shown in FIG. 1, the front portion of the motorcycle 1 is covered with a leg shield 37 and the rear portion thereof is covered with a side cover 38.

  As shown in FIG. 2, a swing shaft 39 projects outward from the clutch cover 28 at the right end of the crankcase 12, and the swing shaft 39 is a kick for starting the engine 11. A starter lever 40 is attached. As shown in FIG. 4, the kick starter lever 40 is disposed on the outer side of the muffler bracket 26, and as shown in FIG. The footrest 41 and the rear brake pedal 42 for stepping on the rear brake with a foot are arranged.

  Thus, in this embodiment, as shown in FIGS. 2 and 3, an exhaust gas sensor 43 is attached between the crankcase 12 of the exhaust pipe 24 and the muffler bracket 26 facing the crankcase 12 in a side view. It is characterized by that. More specifically, as shown in FIG. 4, the exhaust gas sensor 43 is attached to be tilted inward in the vehicle width direction with respect to the vertical line, and its upper portion faces the clutch cover 28 and the clutch cover 28 in a side view. It arrange | positions so that it may be located between the muffler brackets 26.

  As shown in FIG. 2, the exhaust gas sensor 43 is disposed behind and below the swinging shaft 39 of the kick starter lever 40, and its upper portion swings within the swinging surface of the kick starter lever 40. It is tilted to a position that does not overlap with the moving range (see FIG. 4). Here, in the present embodiment, as shown in FIGS. 2 and 3, the exhaust pipe 24 is divided into two parts in the front-rear direction, and an exhaust gas sensor 43 is attached in the vicinity immediately upstream of the connecting portion 24a. A sensor harness 44 (see FIG. 4) extending from the upper portion of the exhaust gas sensor 43 is attached to the pivot bracket 29 in the longitudinal direction.

  As described above, in the present embodiment, the crankcase 12 and the muffler bracket 26 are arranged above the exhaust pipe 24 in the vehicle front-rear direction, and the muffler bracket 26 is opposed to the crankcase 12 in a side view. Since the exhaust gas sensor 43 is mounted between the exhaust gas sensor 43 and the exhaust pipe 24, the exhaust gas sensor 43 does not protrude sideways or upward, and the exhaust gas sensor 43 can be effectively protected from flying stones and jumping water. it can. Further, since a protective plate for protecting the exhaust gas sensor 43 is not required, the exhaust gas sensor 43 is exposed only to the side, and therefore, the exhaust gas sensor 43 is efficiently cooled by the traveling wind and the temperature rise is suppressed. High detection accuracy is ensured.

  In this embodiment, the exhaust gas sensor 43 can be disposed away from the exhaust pipe 24 that is a heat source, and the exhaust pipe 24 can be left exposed outward in the vehicle width direction. The temperature rise of the exhaust pipe 24 and the exhaust gas sensor 43 can be suppressed. Further, since the exhaust pipe 24 is disposed away from the rider, the exhaust pipe 24 is located below the crankcase 12 of the engine 11, but the exhaust gas sensor 43 is tilted inward in the vehicle width direction with respect to the vertical line. In addition, since the upper portion of the exhaust gas sensor 43 is positioned between the clutch cover 28 of the crankcase 12 and the muffler bracket 26 facing the clutch cover 28 in a side view, the exhaust gas sensor 43 is placed on the clutch cover 28 of the crankcase 12. The front and rear of the exhaust gas sensor 43 can be more effectively protected.

  Further, in the present embodiment, the exhaust gas sensor 43 is located behind and below the vehicle body from the swing shaft 39 of the kick starter lever 40 supported by the swing shaft 39 protruding outward from the clutch cover 28 of the crankcase 12. In addition, the exhaust gas sensor 43 interferes with the kick starter lever 40 even when the kick starter lever 40 is operated because the upper portion thereof is tilted to a position that does not overlap the swing range in the swing surface of the kick starter lever 40. Therefore, the exhaust gas sensor 43 can be prevented from being damaged. In addition, since the sensor harness 44 connected to the upper portion of the exhaust gas sensor 43 is located on the inner side in the vehicle width direction than the kick starter lever 40, the sensor harness 44 does not interfere with the kick starter lever 40 and the damage is prevented. Can be removed.

  In the present embodiment, the clutch cover 28 that bulges sideways over the entire length of the crankcase 12 in the front-rear direction constitutes the bulged portion of the crankcase 12, so Since the exhaust gas sensor 43 is disposed, it is possible to prevent the stone or water that the front wheel 5 has flipped up from coming into contact with the exhaust gas sensor 43, and the exhaust gas sensor 43 is effectively protected.

  In the present embodiment, the exhaust gas sensor 43 is attached to the engine 11 integrally with the exhaust pipe 24, and the exhaust pipe 24 and the muffler 25 are integrally attached to the muffler bracket 26, so that the clutch cover 28 of the exhaust gas sensor 43 is attached. Thus, the relative displacement with respect to the muffler bracket 26 can be kept low, and the exhaust gas sensor 43 does not interfere with the surrounding vehicle body components even when the engine 11 vibrates or the rear wheel 35 swings. Damage is prevented.

  Further, in the present embodiment, the exhaust pipe 24 is divided into two parts, and the exhaust gas sensor 43 is attached in the vicinity of the upstream portion of the connecting portion 24a. The exhaust gas sensor 43 is prevented from being damaged without coming into contact with other side parts. In addition, the sensor harness 44 connected to the exhaust gas sensor 43 is not forcibly pulled and disconnected.

  In this embodiment, since the middle portion in the length direction of the sensor harness 44 extending from the upper part of the exhaust gas sensor 43 is attached to the pivot bracket 29, a large amplitude of the sensor harness 44 is prevented, and the sensor harness 44 The occurrence of troubles such as disconnection and erroneous detection by the exhaust gas sensor 43 can be prevented. Furthermore, if the sensor harness 44 is disposed and fixed in the internal space of the pivot bracket 29, the durability of the sensor harness 44 can be further enhanced.

1 is a right side view of a motorcycle equipped with an exhaust device according to the present invention. 1 is a right side view showing a configuration of a main part of a motorcycle including an exhaust device according to the present invention. 1 is a plan view showing a configuration of a main part of a motorcycle including an exhaust device according to the present invention. It is the sectional view on the AA line of FIG.

Explanation of symbols

1 motorcycle 2 head pipe 3 handle 4 front fork 5 front wheel 6 main frame (body frame)
7 Side frame (body frame)
8 Fuel tank 9 Seat 10 Storage box 11 Engine 12 Crankcase 13, 14 Engine bracket 15 Cylinder head 16 Intake pipe 17 Fuel injection device 18 Throttle body 19 Air cleaner 20 Delivery hose 21 Return hose 22 Fuel filter 23 Bypass hose 24 Exhaust pipe 24a Exhaust Pipe connection 25 Muffler 26 Muffler bracket (body parts)
27 Generator cover 28 Clutch cover (expanded part of crankcase)
29 pivot bracket 30 pivot shaft 31 cross member 32, 33 bolt 34 swing arm 35 rear wheel 36 rear cushion 37 leg shield 38 side cover 39 swing shaft 40 kick starter lever 41 footrest 42 rear brake pedal 43 exhaust gas sensor 44 sensor harness

Claims (5)

An engine crankcase disposed below the main frame constituting the vehicle body frame is suspended from the main frame, and an exhaust pipe is attached to a cylinder head extending from the crankcase toward the front of the vehicle body. In the exhaust system of a motorcycle, which is offset from the lower surface of the cylinder head to one side of the crankcase and extends to the rear of the vehicle body, and a muffler is connected to the rear end of the exhaust pipe.
A swing of a kick starter lever pivotally supported by a swinging shaft that protrudes outward from the bulging portion of the crankcase between the crankcase of the exhaust pipe and a vehicle body part facing the crankcase in a side view. Install the exhaust gas sensor tilted inward in the vehicle width direction with respect to the vertical line behind and below the vehicle axis ,
The upper portion of the exhaust gas sensor is positioned between the bulging portion of the crankcase and a vehicle body part that faces the bulging portion in a side view, and the swing range and weight within the swing surface of the kick starter lever. A motorcycle exhaust system that is tilted to a position where it cannot be used. The bulge portion of the crankcase, the exhaust system for a motorcycle according to claim 1, characterized in that the clutch cover. The exhaust system for a motorcycle according to claim 1 or 2 , wherein the vehicle body part is a muffler bracket for attaching the muffler to a vehicle body frame. The exhaust system for a motorcycle according to any one of claims 1 to 3 , wherein the exhaust pipe is divided into two and the exhaust gas sensor is attached in the vicinity of the upstream portion of the connecting portion. The exhaust device for a motorcycle according to any one of claims 1 to 4 , wherein an intermediate portion in a longitudinal direction of a sensor harness extending from an upper portion of the exhaust gas sensor is attached to the vehicle body frame.

Images