JP4952690B2 - Motorcycle exhaust system - Google Patents

Description

  The present invention relates to an exhaust device for a motorcycle including an oxygen sensor for determining a fuel injection amount by detecting an oxygen concentration in exhaust gas.

  Conventionally, in a motorcycle, when a multi-cylinder engine is driven by fuel injection from a fuel injection valve, the exhaust gas passes through a plurality of exhaust pipes extending from each cylinder of the multi-cylinder engine and is then exhausted. An exhaust device that forms an exhaust system that exhausts air in the order of a collecting pipe, an exhaust chamber, and an exhaust muffler is well known.

  In addition, an oxygen sensor is attached to the outer wall downstream of the exhaust collecting pipe in the exhaust direction, and by detecting the oxygen concentration in the exhaust gas by this one oxygen sensor, the opening time of the fuel injection valve, that is, the fuel injection amount is determined. The air-fuel ratio (A / F) is controlled so as to be as close to the theoretical value as possible.

  Note that in a motorcycle equipped with the exhaust chamber described above, in order to ensure an effective layout of the oxygen sensor, a position surrounded by the multi-cylinder engine, the vehicle body frame, and the exhaust chamber is relatively small. Generally, an oxygen sensor is laid out near the center.

  For example, in Patent Document 1, a plurality of exhaust pipes are gathered into one by an exhaust collecting pipe below an engine, and an oxygen sensor (O 2) is connected to a joint portion formed in an exhaust introducing pipe downstream of the exhaust collecting pipe in the exhaust direction. Sensor) is attached.

  The joint portion is offset on the left side of the vehicle body with respect to the vehicle body center line extending in the longitudinal direction of the vehicle body, and the oxygen sensor itself is assumed to extend upward on the left side of the vehicle body.

  Normally, a motorcycle is provided with a side stand (prop stand) on the left side of the vehicle body, and in a parked state using the side stand, the vehicle body is inclined such that the left side of the vehicle body is at a low position. As a result, the released oxygen sensor extends substantially horizontally (or downward) with respect to the ground.

  In general, due to the structure of the oxygen sensor, the detection unit is vulnerable to water. Therefore, when the oxygen sensor extends substantially horizontally (or downward) in a parked state, moisture condensed in the exhaust passage is detected by the oxygen sensor detection unit. There is a risk of touching.

  As a result, the oxygen sensor does not operate accurately for a certain period immediately after the engine is started, and it becomes difficult to perform accurate fuel injection control.

  In order to avoid such a problem, when the oxygen sensor is extended upward close to the vertical direction, there is a possibility that the oxygen sensor may be lost due to interference with a side stand that is not in use (stored) such as running.

  Further, since a rear swing arm, a swinging member, and the like are disposed above the joint portion, there is a possibility that these components and the oxygen sensor come into contact when the rear wheel swings.

For this reason, in order to avoid interference between these components and the oxygen sensor, the oxygen sensor has to be extended sideways (lay down), and as described above, it is adversely affected when the engine is started after parking. It will be.
JP 2007-321595 A

  As described above, when the oxygen sensor having poor water resistance is laid out, the motorcycle is parked, that is, the vehicle body is tilted by the three-point support of the front and rear wheels and the side stand (leaning on the side stand side). In other words, there is a problem that the layout arrangement is constrained in consideration of the state) and the presence of peripheral equipment.

  Also, if the exhaust pipe is laid out near the center of the vehicle body relative to the multi-cylinder engine, the oxygen sensor is laid out near the center of the exhaust pipe near the center of the vehicle body because it is easily affected by the bank angle. There was also a problem that this was difficult.

  If such an exhaust pipe is laid out near the center of the vehicle body with respect to the multi-cylinder engine and an oxygen sensor is laid out near the center of the vehicle body of the exhaust pipe, the influence on the overall appearance of the motorcycle will be affected. As a result, a process such as covering the oxygen sensor with a cover is required, resulting in an increase in the number of parts and a problem that costs such as parts cost and assembly cost are increased.

  In view of the above circumstances, an object of the present invention is to provide an exhaust device for a motorcycle that can secure a layout arrangement suitable for use conditions of an oxygen sensor without impairing the appearance.

  An exhaust device for a motorcycle according to the present invention includes an engine mounted between a pair of left and right main frames, an exhaust pipe extending from the engine toward a rear lower part of a vehicle body, and the exhaust pipe and an engine disposed below the engine. And an exhaust collecting pipe disposed to be deviated to one side in the vehicle width direction with respect to the vehicle body center line along the vehicle body longitudinal direction and spaced from the exhaust chamber in front of the vehicle body. And an oil pan for storing engine oil, and the oil pan bulges downward from the vehicle body so as to sandwich the vehicle centerline between the oil pan and the exhaust collecting pipe. An oil reservoir that is spaced apart and opposed to a part of the exhaust chamber in the front-rear direction of the vehicle body is formed, and the exhaust collecting pipe is disposed between the part of the exhaust chamber and the oil reservoir. Wherein the oxygen sensor for detecting oxygen concentration in exhaust gas reaching the air chamber is disposed.

  According to the exhaust system for a motorcycle according to claim 1, the oil storage bulges from below the oil pan near the vehicle body center line by biasing the exhaust collecting pipe to one side in the vehicle width direction from the vehicle body center line. The oxygen sensor can be protected from stepping stones and flying water during traveling or the like by forming the portion and disposing the oxygen sensor behind the oil reservoir in the vehicle body.

  According to a second aspect of the present invention, there is provided an exhaust device for a motorcycle, wherein an exhaust introduction pipe is interposed between the exhaust collecting pipe and the exhaust chamber and communicates with the exhaust gas in an outer wall surface of the exhaust introduction pipe. The oxygen sensor is arranged on the outer wall surface in the direction opposite to the biasing direction of the collecting pipe.

  According to the exhaust apparatus for a motorcycle according to claim 2, by arranging the oxygen sensor on the outer wall surface of the exhaust inlet pipe opposite to the displacement direction of the exhaust collecting pipe, the vehicle width of the oxygen sensor is increased. The amount of protrusion outward in the direction can be reduced, and an oxygen sensor can be efficiently arranged between a part of the exhaust chamber and the oil reservoir, and interference with other movable parts can be avoided. Can be made easier.

  The exhaust system for a motorcycle according to claim 3 is characterized in that the exhaust collecting pipe is biased to the same side as the vehicle body installation side of the side stand that is in use when the vehicle is parked.

  According to the exhaust device for a motorcycle according to claim 3, the oxygen sensor can be positioned on the side opposite to the leaning side, that is, on the high side of the exhaust passage, with respect to the vehicle body leaning on the side stand side when the vehicle is parked. Therefore, it is possible to make it difficult for the oxygen sensor to come into contact with moisture condensed on the lower side of the exhaust passage than the oxygen sensor, and it is possible to contribute to improvement in detection accuracy of the oxygen concentration in the exhaust gas at the time of starting the engine.

  In addition, since the oxygen sensor is arranged on the side opposite to the side stand, it is not necessary to avoid the trajectory of the side stand, the extending direction of the oxygen sensor can be made substantially horizontal, and the clearance between the engine bottom and the exhaust device is narrowed. Can contribute to lowering the center of gravity.

  The exhaust system for a motorcycle according to claim 4, wherein the exhaust chamber is disposed substantially at the center in the vehicle width direction, and the exhaust collecting pipe and the exhaust chamber are biased to one side in the vehicle width direction from the vehicle body center line. Are connected by the exhaust introduction pipe inclined with respect to the longitudinal direction of the vehicle body, and an axis substantially parallel to the exhaust flow direction of the exhaust introduction pipe is provided to exhaust the exhaust gas into the exhaust chamber at the rear end of the exhaust introduction pipe. The catalyst device is arranged.

  According to the exhaust apparatus for a motorcycle according to claim 4, by arranging the exhaust catalyst apparatus along the exhaust flow direction in the exhaust introduction pipe, it is possible to improve exhaust gas exhaust and improve engine output. .

  Further, since the exhaust gas flow can be formed without having a large incident angle with respect to the exhaust catalyst device, the exhaust gas can flow evenly into the exhaust catalyst device and contribute to the equalization of the catalyst use region. Thus, exhaust purification efficiency can be improved.

  Furthermore, although the exhaust collecting pipe is biased to one side in the vehicle width direction, the heavy exhaust catalyst device can be arranged near the center in the vehicle width direction, and the weight balance on the left and right sides of the vehicle body can be improved. By arranging a large-diameter exhaust catalyst device near the center in the vehicle width direction, the height dimension at the left and right ends of the interior of the exhaust chamber can be reduced, and as a result, a large bank angle can be secured and the vehicle turns. The performance can be improved.

  The motorcycle exhaust system of the present invention can ensure a layout arrangement suitable for the use condition of the oxygen sensor without impairing the appearance.

  Next, a motorcycle exhaust device according to an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is a left side view of a motorcycle equipped with an exhaust device according to an embodiment of the present invention, FIG. 2 is a left side view of the main part of the exhaust device of the motorcycle according to an embodiment of the present invention, and FIG. Fig. 4 is a right side view of a main part of an exhaust device for a motorcycle according to an embodiment of the present invention. Fig. 4 is a bottom view of the main part of the exhaust device for a motorcycle according to an embodiment of the present invention. FIG. 6 is a cross-sectional view (a cross-sectional view taken along line AA in FIG. 4) of the main part of the exhaust device for a motorcycle according to an embodiment.

  As shown in FIGS. 1 to 4, a motorcycle 1 according to an embodiment of the present invention includes a pair of left and right main frames 3 and 3 that extend from a head pipe 2 disposed on the front side to the left and right of the vehicle body. A vehicle body frame 4, a seat 6 fixed to a seat frame (not shown) extending rearwardly via a bracket 5 provided in the middle of the main frames 3, 3, and the main frames 3, 3 An engine 7 mounted on the vehicle, a front fork 9 that is connected to the head pipe 2 and pivotally supports the front wheel 8, a rear swing arm 11 that is connected to the main frames 3 and 3 and supports the rear wheel 10, and the main frame 3 , 3 and a vehicle body cowling 12 straddling the vehicle body left and right so as to cover the engine 7 from the front of the vehicle body, and a fuel tank 13 disposed in front of the seat 6.

  The main frames 3 and 3 are bent so as to avoid the generator cover 14 disposed on the left side of the vehicle body and the clutch cover 15 disposed on the right side of the vehicle body. Further, a radiator 16 and a reservoir tank 17 constituting an engine cooling system for cooling the engine 7 are disposed in front of the main frames 3 and 3 at the front and rear of the vehicle body, and an outlet side radiator hose is disposed on the left side of the vehicle body. 18, On the right side of the vehicle body, an inlet side radiator hose 19 is arranged. The radiator hoses 18 and 19 communicate with each other via a water pump 20 and a water jacket formed in the cylinder and cylinder head of the engine 7.

  An oil cooler 21 serving as an engine oil cooling system is disposed below the radiator 16, and each end of an inlet-side oil hose 22 and an outlet-side oil hose 23 is provided on the oil cooler 21 on the right side of the vehicle body. It is connected. The other end of the inlet side oil hose 22 is connected to the oil filter 24, and the other end of the outlet side oil hose 23 is connected to a main gallery (not shown) formed in the engine 7.

  On the other hand, one end of a plurality of exhaust pipes 25 corresponding to the number of cylinder heads is connected to a cylinder head portion (not shown) of the engine 7. Further, the plurality of exhaust pipes 25, 25... Are connected to exhaust mufflers 29, 29 extending through the exhaust collecting pipe 26, the exhaust introduction pipe 27, and the exhaust chamber 28 in this order to the rear upper left and right sides of the vehicle body. ing. Further, an oil pan 30 for storing engine oil as an engine lubrication system is arranged on the right side of the vehicle body of the exhaust collecting pipe 26, and an exhaust control valve (shown by a valve shaft 31 in FIG. 4) is located on the left side of the exhaust collecting pipe 26 in the vehicle body. Drive pulley 32 is arranged.

  Note that one end of a cable 33 is connected to the drive pulley 32. The other end of the cable 33 is connected to an actuator 36 that is connected to the main frames 3 and 3 and is supported by one of the engine suspension portions 34 and 34 (the left side of the vehicle body) substantially supporting the engine 7 via a bracket 35. It is connected.

  At this time, the engine suspension portions 34, 34 form a substantially triangular space with the main frames 3, 3, and the actuator 36 is arranged in the triangular space, whereby the actuator 36 is moved to the main frame 3, 3. 3 can be assembled from the outside.

  The exhaust collecting pipe 26 is laid out on the left side of the vehicle body with respect to the vehicle body center line Q (see FIG. 4) extending in the longitudinal direction of the vehicle body, and the exhaust chamber 28 is arranged at substantially the center of the vehicle body.

  Thus, the exhaust introduction pipe 27 is inclined so as to approach the vehicle body center line Q from the position deviated from the vehicle body center line Q to the left side of the vehicle body toward the downstream side in the exhaust direction. An oxygen sensor 37 that detects the oxygen concentration of the exhaust gas in the exhaust gas in the pipe is disposed in the middle of the exhaust introduction pipe 27. Further, the rear end side of the vehicle body of the exhaust introduction pipe 27 faces the exhaust chamber 28, and an exhaust catalyst device 38 is provided at the rear end thereof.

  The oxygen sensor 37 has an outer wall surface (exhaust in plan view) opposite to the vehicle body displacement side of the exhaust collecting pipe 26 in the middle of the exhaust introduction pipe 27 that is inclined to one side in the vehicle width direction with respect to the longitudinal direction of the vehicle body. The introduction pipe 27 protrudes from an outer wall surface in the vicinity of a portion overlapping the vehicle body center line Q, and the extending direction is substantially horizontal when traveling (vehicle body horizontal state) is a reference. Therefore, as shown in FIG. 5, when the vehicle is parked using the side stand 39 provided on the left side of the vehicle body so as to be rotatable, if the vehicle body is tilted to lean against the side stand 39, oxygen The sensor 37 extends upward (see, for example, the angle θ shown in FIG. 5). As shown in FIG. 4, the oxygen sensor 37 is formed below the oil pan 30 and swells downward in the vehicle body so as to sandwich the vehicle body center line Q with the exhaust collecting pipe 26. 30 a and a part of the exhaust chamber 28.

  The same effect can be obtained not only for the oxygen sensor 37 but also for the layout arrangement of various sensors having poor water resistance (for example, an air-fuel ratio sensor).

  The exhaust catalyst device 38 is inclined (for example, 5 ° or more) with respect to the vehicle body center line Q in plan view as the exhaust introduction pipe 27 is inclined, so that the exhaust flow can be smoothly performed and the engine output can be improved. Can contribute. Further, by making the exhaust flow in the vicinity of the inlet of the exhaust catalyst device 38 substantially parallel to the flow in the exhaust catalyst device 38, the usage area of the exhaust catalyst device 38 can be equalized, and the exhaust gas purification performance is improved. It can contribute to improvement and durability improvement.

  As described above, in the motorcycle exhaust system according to the present invention, the plurality of exhaust pipes 25, 25... Are gathered in the exhaust collecting pipe 26 below the engine 7, and the exhaust collecting pipe 26 is closer to the downstream in the exhaust direction. In addition, an oxygen sensor 37 is installed upstream of the exhaust chamber 28, and the exhaust collecting pipe 26 is laid out in a layout manner on the side of the side stand 39 installed on the left side of the vehicle body, and the oxygen sensor 37 is arranged in the exhaust collecting pipe 26. Even when the oxygen sensor 37 is mounted in a substantially horizontal position so as to extend in the vehicle width direction by being laid out on the side opposite to the vehicle width direction, the side stand 39 is used ( In the parking state), the oxygen sensor 37 can be extended upright from the horizontal, and the detection part of the oxygen sensor 37 is prevented from contacting moisture in the exhaust passage. Obtained, it is possible to perform fuel injection control immediately after the engine 7 starts more accurately.

  Further, since the extending direction of the oxygen sensor 37 is opposite to the side stand 39, the possibility of contact with the side stand 39 can be eliminated.

  Furthermore, since the oxygen sensor 37 can be mounted on its side, the clearance between the oxygen sensor 37 and the engine 7 or the vehicle body side parts can be avoided and the mutual clearance can be reduced, thereby reducing the center of gravity of the vehicle body. be able to.

  In addition, the exhaust collecting pipe 26 is biased toward the side stand 39, and an oil reservoir 30a bulging downward from the lower portion of the oil pan 30 located on the opposite side is formed. By disposing the sensors 37 so as to be adjacent to each other, the oil reservoir 30a can be used as a protection member, and the oxygen sensor 37 can be protected from flying stones and flying water during traveling.

  Further, the exhaust chamber 28 located downstream of the oxygen sensor 37 in the exhaust direction is centered so as to be closer to the vehicle body center line Q, and the exhaust introduction pipe 27 from the exhaust collecting pipe 26 to the exhaust chamber 28 is connected to the vehicle body. By attaching an exhaust catalyst device 38 to the rear end portion of the exhaust introduction pipe 27 that is inclined with respect to the front-rear direction and whose rear portion is located in the exhaust chamber 28, an exhaust catalyst device that is heavy in the center of the exhaust chamber 28. 38 can be arranged.

  As a result, the weight balance between the left and right sides of the vehicle body is improved, and a large exhaust catalyst device 38 is housed in the center of the exhaust chamber 28 to reduce the height dimension near the left and right ends, thereby ensuring a large bank angle. The turning performance of the vehicle can be improved.

  Further, the exhaust catalyst device 38 attached to the rear portion of the exhaust introduction pipe 27 is configured such that its axial direction is substantially parallel to the exhaust flow direction, thereby reducing the exhaust resistance inside the honeycomb-shaped exhaust catalyst device 38. This can greatly reduce the output of the engine 7 and contribute to the improvement of the output.

  Further, by arranging the exhaust catalyst device 38 along the exhaust flow direction, the exhaust gas can flow evenly in the exhaust catalyst device 38, which contributes to the improvement of exhaust purification efficiency.

  In particular, since the exhaust introduction pipe 27 is provided to be inclined with respect to the longitudinal direction of the vehicle body, the mounting seat surface of the oxygen sensor 37 can also be inclined with respect to the longitudinal direction of the vehicle body. The projected area can be reduced, and the entire oxygen sensor 37 can be hidden behind the oil reservoir 30a.

1 is a left side view of a motorcycle equipped with an exhaust device according to an embodiment of the present invention. 1 is a left side view of a main part of an exhaust device for a motorcycle according to an embodiment of the present invention. 1 is a right side view of a main part of an exhaust device for a motorcycle according to an embodiment of the present invention. FIG. 3 is a bottom view of the main part of the exhaust device for a motorcycle according to an embodiment of the present invention. FIG. 6 is a cross-sectional view (cross-sectional view taken along the line AA shown in FIG. 4) of the main part of the exhaust device for a motorcycle according to an embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 3 ... Main frame 7 ... Engine 25 ... Exhaust pipe 26 ... Exhaust collecting pipe 27 ... Exhaust introduction pipe 28 ... Exhaust chamber 37 ... Oxygen sensor 38 ... Exhaust catalyst apparatus

Claims (4)

An engine mounted between a pair of left and right main frames, an exhaust pipe extending from the engine toward the rear lower part of the vehicle body, and the exhaust pipe and an exhaust chamber disposed below the engine are connected to the vehicle body. An exhaust collecting pipe arranged to be deviated to one side in the vehicle width direction from the vehicle body center line along the front-rear direction, an oil pan that is arranged farther forward of the vehicle body than the exhaust chamber and stores engine oil; In the exhaust system of a motorcycle equipped with
The oil pan has an oil reservoir that bulges downward toward the vehicle body so as to sandwich the vehicle body center line between the oil collecting pipe and a part of the exhaust chamber that is spaced apart and opposed in the vehicle longitudinal direction. And an oxygen sensor for detecting an oxygen concentration in the exhaust gas extending from the exhaust collecting pipe to the exhaust chamber is disposed between a part of the exhaust chamber and the oil reservoir. Motorcycle exhaust system.   An exhaust introduction pipe is connected between the exhaust collection pipe and the exhaust chamber, and the oxygen is disposed on the outer wall surface of the exhaust introduction pipe in a direction opposite to the displacement direction of the exhaust collection pipe. The exhaust device for a motorcycle according to claim 1, further comprising a sensor.   The exhaust system for a motorcycle according to claim 1 or 2, wherein the exhaust collecting pipe is biased to the same side as a vehicle body installation side of a side stand that is in use when the vehicle is parked.   The exhaust chamber is disposed substantially in the center in the vehicle width direction, and the exhaust pipe and the exhaust chamber that are biased to one side in the vehicle width direction with respect to the vehicle body center line are inclined with respect to the vehicle body longitudinal direction. And an exhaust catalyst device is disposed in the exhaust chamber at the rear end of the vehicle body of the exhaust introduction pipe by giving an axis substantially parallel to the exhaust flow direction of the exhaust introduction pipe. The exhaust device for a motorcycle according to any one of claims 3 to 4.

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