JPWO2019059258A1 - Saddle type vehicle - Google Patents

Abstract

The saddle-ride type vehicle (11) is arranged under the vehicle body frame (12), the engine (28) suspended on the vehicle body frame (12), and the engine (28), and exhaust gas emitted from the engine (28) is discharged. A catalyst (43) to be purified, a silencer (45) arranged downstream of the catalyst (43) along the flow direction of the exhaust gas, and a silencer (43) arranged downstream of the catalyst (43) along the flow direction. The cross section of the catalyst (43) is sandwiched between the downstream exhaust pipe (44) connected to the silencer (45) and the downstream exhaust pipe (44) and the catalyst (43) with a cross section smaller than the cross section of And a connecting pipe (47) having an expansion chamber (55) having a large cross section. This provides a saddle-ride type vehicle in which the length of the exhaust pipe for each cylinder can be sufficiently secured and the exhaust pressure can be sufficiently reduced downstream of the catalyst.

Description

The present invention relates to a saddle type vehicle such as a motorcycle, and particularly to an engine suspended on a body frame, a catalyst arranged under the engine for purifying exhaust gas discharged from the engine, and a catalyst arranged along a flow direction of the exhaust gas. The present invention relates to a saddle-ride type vehicle including a silencer arranged downstream of the catalyst and a downstream exhaust pipe arranged downstream of the catalyst along the flow direction and connected to the silencer with a cross section smaller than the cross section of the catalyst.

Patent Document 1 discloses a motorcycle. The motorcycle has an exhaust device. The exhaust device is arranged behind the exhaust pipe connected to the exhaust passage of the cylinder head, the catalyst installed in the middle position of the exhaust pipe, and the swing axis of the center stand, and is located downstream of the catalyst and behind the exhaust pipe. And a silencer connected to the end. The catalyst is located in front of the engine. Since the catalyst and the silencer are separated from each other, a sufficient volume is secured in the exhaust gas passage between the catalyst and the silencer. Therefore, the exhaust pressure is sufficiently lowered downstream of the catalyst and the output of the engine is increased.

Japanese Unexamined Patent Publication No. 2016-56788

When the exhaust gas from a plurality of cylinders merges and flows into the catalyst, the longer the exhaust pipe for each cylinder, the more the influence of pulsation between the exhaust pipes can be suppressed. However, when the position of the catalyst approaches the muffler, a sufficient volume cannot be secured in the exhaust gas passage between the catalyst and the muffler, the exhaust pressure increases downstream of the catalyst, and the output of the engine decreases. Will end up.

The present invention has been made in view of the above circumstances, and provides a saddle-ride type vehicle that can sufficiently secure the length of the exhaust pipe for each cylinder and can sufficiently reduce the exhaust pressure downstream of the catalyst. The purpose is to

According to the first aspect of the present invention, a vehicle body frame, an engine suspended on the vehicle body frame, a catalyst disposed under the engine, for purifying exhaust gas discharged from the engine, and a flow direction of the exhaust gas. A silencer disposed downstream of the catalyst, a downstream exhaust pipe disposed downstream of the catalyst along the flow direction and connected to the silencer at a cross section smaller than the cross section of the catalyst, and A saddle-ride type vehicle is provided that includes a downstream exhaust pipe and a connecting pipe sandwiched between the catalyst and an expansion chamber having a cross section larger than the cross section of the catalyst.

According to the second aspect, in addition to the configuration of the first aspect, the catalyst is arranged at a position offset from the central symmetrical plane of the vehicle body in the vehicle width direction to one side in the vehicle width direction, and the expansion chamber is Swells in the direction opposite to the one.

According to the third aspect, in addition to the configuration of the first or second aspect, the engine has an oil pan arranged side by side with the catalyst in the vehicle width direction, and the expansion chamber has the oil pan of the oil pan. Inflate towards the rear space.

According to the fourth aspect, in addition to the configuration of any of the first to third aspects, the connecting pipe is arranged in the space in front of the center stand.

According to the fifth aspect, in addition to the configuration of any of the first to fourth aspects, an exhaust gas sensor is installed in the downstream exhaust pipe.

According to the sixth aspect, in addition to the configuration of any of the first to fifth aspects, the connecting pipe has a stay connected to the vehicle body frame or the engine, and the stay is arranged in the vehicle width direction. It is arranged in a direction opposite to the bulge of the expansion chamber.

According to the seventh aspect, in addition to the configuration of the fourth aspect, the connection pipe is formed with a recess for disposing the space occupied by the center stand.

According to the eighth aspect, in addition to the configuration of any one of the first to seventh aspects, the expansion chamber is hidden behind the catalyst in a front view of the vehicle.

According to the ninth aspect, in addition to the configuration of the first aspect, the exhaust gas sensor is provided upstream of the catalyst along the flow direction and is held in a posture inclined from a vertical line defining the gravity direction.

According to the tenth aspect, in addition to the configuration of the fifth aspect, the exhaust gas sensor is at a position that at least partially overlaps the brake pedal in a vehicle side view.

According to the first aspect, the expansion chamber increases the volume of the exhaust gas passage between the catalyst and the downstream exhaust pipe, as compared with the case where the downstream exhaust pipe is directly connected to the downstream end of the catalyst. Therefore, even if the distance between the catalyst and the silencer is shortened, a sufficient volume can be secured in the exhaust gas passage between the catalyst and the silencer. Downstream of the catalyst, the exhaust pressure drops sufficiently and the engine power increases.

According to the second aspect, the catalyst is arranged below the engine in the vehicle width direction, but the connecting pipe swells so as to sunk below the engine. Therefore, the protrusion of the connecting pipe in the vehicle width direction below the engine does not occur. Suppressed. Therefore, the bank angle of the saddle type vehicle is sufficiently secured.

According to the third aspect, since the connecting pipe bulges toward the space behind the oil pan, it is possible to secure the capacity of the expansion chamber while avoiding interference with the oil pan.

According to the fourth aspect, since the expansion chamber expands while avoiding interference with the center stand, it is possible to secure the capacity of the expansion chamber while ensuring the function of the center stand.

According to the fifth aspect, the exhaust gas sensor can thus be arranged downstream of the expansion chamber. Since the flow of exhaust gas is stable downstream of the expansion chamber, the influence of pulsation of exhaust gas can be suppressed as much as possible during sensing.

According to the sixth aspect, since the stay is provided integrally with the connecting pipe, the number of parts is reduced. Further, since the stay is arranged in the direction opposite to the bulge of the expansion chamber, it is possible to avoid applying a load to the bulge which is weak in design.

According to the seventh aspect, since the recess is formed in the connecting pipe, the interference between the connecting pipe and the center stand can be avoided.

According to the eighth aspect, since the expansion chamber is hidden behind the catalyst when the vehicle is viewed from the front, the catalyst can protect the expansion chamber from pebbles and the like flying from the front. Damage to the expansion chamber can be prevented.

According to a ninth aspect, the exhaust gas sensor arranged upstream of the catalyst is arranged below the engine. Since the exhaust gas sensor is held in a posture inclined from the vertical line, the exhaust pipe can be arranged at a position as high as possible while avoiding interference between the exhaust gas sensor and the engine. In this way, the minimum ground clearance can be secured.

According to the tenth aspect, since the exhaust gas sensor overlaps the brake pedal when the vehicle is viewed from the side, the exhaust gas sensor can be protected by the brake pedal.

FIG. 1 is a side view schematically showing an overall image of a motorcycle according to an embodiment of the present invention. FIG. 2 is an enlarged partial side view of FIG. (First embodiment) FIG. 3 is an enlarged view of the engine unit observed from the front of the motorcycle. (First embodiment) FIG. 4 is an enlarged vertical sectional view taken along line 4-4 of FIG. (First embodiment) FIG. 5 is an enlarged view of the motorcycle observed from below. (First embodiment)

11...Saddle-type vehicle (motorcycle)
12... Body frame 28... Engine 32... Center stand 43... Catalyst 44... Downstream exhaust pipe 45... Silencer 47... Connection pipe 48... Exhaust gas sensor (first exhaust gas sensor)
49... Exhaust gas sensor (second exhaust gas sensor)
51... Stay 53... Oil pan 55... Expansion chamber 59... Brake pedal 61... Vertical line 66... Recess SP... Central symmetry plane.

An embodiment of the present invention will be described below with reference to the accompanying drawings. Here, the upper, lower, front, rear, left, and right of the vehicle body are defined based on the eyes of an occupant who rides on the motorcycle.

First embodiment

FIG. 1 schematically shows an overall image of a saddle type vehicle, that is, a motorcycle according to an embodiment. The motorcycle 11 includes a body frame 12 that forms the skeleton of the vehicle. The body frame 12 includes a head pipe 13, a pair of left and right main frames 14 extending rearward and downward from the head pipe 13, and a pair of left and right down frames 15 extending downward and rearward from the head pipe 13 below the main frame 14. , A pair of left and right pivot frames 16 coupled to the rear ends of the individual main frames 14 and extending downward, and a pair of left and right seat frames 17 extending rearward and upward from the individual main frames 14. An occupant seat 19 is mounted on the seat frame 17 behind the fuel tank 18.

A front fork 21 is steerably supported by the head pipe 13. A front wheel WF is supported on the front fork 21 so as to be rotatable around an axle 22. A steering handle 23 is connected to the upper end of the front fork 21.

A swing arm 25 is connected to the pivot frame 16 at the rear of the vehicle so as to be swingable up and down around the pivot 24. A rear wheel WR is supported on the rear end of the swing arm 25 so as to be rotatable around an axle 26. A heel guard 56 is fixed to the pivot frame 16 behind the pivot 24. A bracket 57 extending downward from the heel guard 56 is integrally formed with the heel guard 56. A step 58r is removably attached to the bracket 57. A brake pedal 59 is arranged inside the bracket 57 so as to be swingable around a swing shaft at the rear end. An occupant who straddles the occupant seat 19 can put his/her feet on the step 58r. The heel can be pressed against the heel guard 56. The occupant can step on the brake pedal 59 with the foot placed on the step 58r. An engine unit 27 is mounted on the body frame 12 between the front wheels WF and the rear wheels WR. The engine unit 27 includes an engine 28 that generates a driving force transmitted to the rear wheels WR.

The engine 28 is suspended on the body frame 12. The lower end of the main frame 14 is connected to the rear side of the engine 28, and the lower end of the down frame 15 is connected to the front side of the engine 28. Thus, the rigid structure is established by the engine 28 in addition to the main frame 14 and the down frame 15. The left and right pivot frames 16 are connected to each other by a cross tube 29 extending in the horizontal direction. A center stand 32 is connected to the cross tube 29 so as to be swingable around a swing axis 31.

The engine 28 includes a crankcase 34 that rotatably supports a crankshaft about a rotation axis 33 that extends parallel to the axle 26, and a cylinder that is coupled to the crankcase 34 and that accommodates a piston movably along a cylinder axis C. A cylinder head 36, which is connected to the block 35 and the cylinder block 35 to define a combustion chamber between the block 35 and the cylinder head 36, is connected to the cylinder head 36, and a camshaft 37 is rotatably sandwiched between the cylinder head 36 and the cylinder head 36. And a head cover 38. An intake passage and an exhaust passage connected to the combustion chamber are defined in the cylinder head 36. An intake valve is arranged in the intake passage. The intake valve opens and closes the intake port according to the rotation of the camshaft 37. An exhaust valve is arranged in the exhaust passage. The exhaust valve opens and closes the exhaust port according to the rotation of the camshaft 37.

An intake device (not shown) is connected to the rear wall of the cylinder head 36. An exhaust device 41 is connected to the front wall of the cylinder head 36. The exhaust device 41 includes individual upstream exhaust pipes 42a and 42b connected to the exhaust passage of the cylinder head 36 for each cylinder, a catalyst 43 disposed under the engine 28, and purifying exhaust gas emitted from the engine 28, and exhaust gas. And a downstream exhaust pipe 44 arranged downstream of the catalyst 43 along the flow direction of the catalyst 43, and arranged downstream of the swing axis 31 of the center stand 32 and connected to the rear end of the downstream exhaust pipe 44 downstream of the catalyst 43. Of the silencer 45, a plurality of upstream exhaust pipes 42a and 42b, and an introduction pipe 46 that connects the upstream end of the catalyst 43 to the upstream exhaust pipes 42a and 42b, and the downstream exhaust pipe 44 and the catalyst 43. A connecting pipe 47, which is sandwiched in between, connects the downstream exhaust pipe 44 to the downstream end of the catalyst 43.

As shown in FIG. 2, a first exhaust gas sensor 48 is attached to the introduction pipe 46 on the upstream side of the catalyst 43. The first exhaust gas sensor 48 is arranged below the engine 28 and is held in a posture inclining from a vertical line 61 that defines the direction of gravity. The first exhaust gas sensor 48 is composed of, for example, an O2 sensor. The first exhaust gas sensor 48 measures the oxygen concentration in the exhaust gas flowing through the introduction pipe 46.

A second exhaust gas sensor 49 is attached to the downstream exhaust pipe 44 on the downstream side of the catalyst 43. The second exhaust gas sensor 49 is composed of, for example, an O2 sensor. The second exhaust gas sensor 49 measures the oxygen concentration in the exhaust gas flowing through the downstream exhaust pipe 44. The second exhaust gas sensor 49 is disposed inside the brake pedal 59, and is at a position that at least partially overlaps the brake pedal 59 in a vehicle side view.

The center stand 32 includes a shaft body 62 extending parallel to the axle 26 of the rear wheel WR. The shaft center of the shaft body 62 overlaps the swing axis line 31. The shaft body 62 is rotatably held at the lower end of a stand stay 63 extending downward from the cross tube 29.

The connecting pipe 47 has a stay 51 connected to the pivot frame 16 of the vehicle body frame 12. The stay 51 is fixed to the connecting pipe 47 by welding, for example. The pivot frame 16 is integrally formed with a bracket 52 that extends forward from the pivot frame 16 and receives the tip of the stay 51. The stay 51 is bolted to the bracket 52. In this way, the exhaust device 41 is fixed to the vehicle body frame 12 between the front ends of the upstream exhaust pipes 42a and 42b and the silencer 45.

As shown in FIG. 3, the cylinder block 35 is arranged in the vehicle width direction and defines a plurality of cylinders, that is, cylinders 52, which individually guide the movement of the pistons. Upstream exhaust pipes 42a and 42b are connected to the cylinder head 36 for each individual cylinder 52. The bottom plate of the crankcase 34 defines the oil pan 53. The catalyst 43 is arranged at a position deviated from the central plane of symmetry SP of the vehicle body in the vehicle width direction to one side in the vehicle width direction. The oil pan 53 is biased to the other side in the vehicle width direction from the central plane of symmetry SP. The catalyst 43 and the oil pan 53 are arranged side by side in the vehicle width direction. The step 58l is arranged at the left-right symmetrical position of the step 58r with respect to the central plane of symmetry SP. The shift change lever 65 is associated with step 58l.

The oil in the crankcase 34 is filled in the oil pan 53. An oil pump (not shown) sucks oil from an oil pan 53 in association with the rotation of the crankshaft. The oil of the oil pump is filtered by the oil filter 54 and then supplied to the contact area between the crankpin and the connecting rod, the contact area between the piston and the cylinder, the transmission gear of the transmission, and the like. The oil filter 54 is detachably attached to the front wall of the crankcase 34. The upstream exhaust pipes 42a and 42b are curved in the vehicle width direction at the position of the oil filter 54 when the vehicle is viewed from the front. As shown in FIG. 4, the upper end of the first exhaust gas sensor 48 tilts outward in the vehicle width direction. A sensor cable 64 is connected to the upper end of the first exhaust gas sensor 48. The sensor cable 64 extends upward along the side of the engine 28.

As shown in FIG. 5, the connecting pipe 47 defines an expansion chamber 55 having a cross section larger than that of the catalyst 43. The expansion chamber 55 expands in a direction opposite to the biasing direction of the catalyst 43. That is, the expansion chamber 55 expands toward the central plane of symmetry SP in the vehicle width direction. The connecting pipe 47 is arranged in a space behind the oil pan 53 and in front of the center stand 32. The stay 51 is arranged in a direction opposite to the bulge of the expansion chamber 55 with respect to the vehicle width direction. As is clear from FIG. 3, the expansion chamber 55 is hidden behind the catalyst 43 when the vehicle is viewed from the front.

The downstream exhaust pipe 44 has a cross section smaller than that of the catalyst 43 and extends from the connecting pipe 47 to the silencer 45. The upstream end of the downstream exhaust pipe 44 is connected to the connecting pipe 47 at a position biased away from the central plane of symmetry SP. As a result, the connecting pipe 47 is formed with a recess 66 for disposing the space occupied by the center stand 32. From the connecting pipe 47 to the silencer 45, the diameter of the downstream exhaust pipe 44 is maintained. The downstream exhaust pipe 44 is connected to the silencer 45 with a cross section smaller than the cross section of the catalyst 43.

Next, the operation of this embodiment will be described. In the motorcycle 11 according to the present embodiment, the connecting pipe 47 is sandwiched between the downstream exhaust pipe 44 and the catalyst 43. The connecting pipe 47 defines an expansion chamber 55 having a cross section larger than the cross section of the catalyst 43 downstream of the catalyst 43. The expansion chamber 55 increases the volume of the exhaust gas passage between the catalyst 43 and the downstream exhaust pipe 44 as compared with the case where the downstream exhaust pipe 44 is directly connected to the downstream end of the catalyst 43. Therefore, even if the distance between the catalyst 43 and the silencer 45 is shortened, a sufficient volume can be secured in the exhaust gas passage between the catalyst 43 and the silencer 45. The exhaust pressure is sufficiently lowered downstream of the catalyst 43 and the output of the engine 28 is increased.

In the present embodiment, the catalyst 43 is arranged at a position offset from the central plane of symmetry SP in the vehicle width direction of the vehicle body to one side in the vehicle width direction. On the other hand, the expansion chamber 55 swells in the opposite direction to the one. Although the catalyst 43 is arranged below the engine 28 in the vehicle width direction, the connecting pipe 47 swells so as to sink under the engine 28. Therefore, the protrusion of the connecting pipe 47 in the vehicle width direction below the engine 28 is suppressed. To be done. Therefore, the bank angle of the motorcycle 11 is sufficiently secured.

The oil pan 53 of the engine 28 and the catalyst 43 are arranged side by side in the vehicle width direction. The connecting pipe 47 bulges toward the space behind the oil pan 53. In this way, since the connecting pipe 47 bulges toward the space behind the oil pan 53, the capacity of the expansion chamber 55 can be secured while avoiding interference with the oil pan 53. In addition, the connecting pipe 47 bulges toward the space in front of the center stand 32. In this way, since the expansion chamber 55 expands while avoiding interference with the center stand 32, the capacity of the expansion chamber 55 can be secured while ensuring the function of the center stand 32.

In the motorcycle 11 according to the present embodiment, the second exhaust gas sensor 49 is installed in the downstream exhaust pipe 44 downstream of the connecting pipe 47. In this way, the second exhaust gas sensor 49 is arranged downstream of the expansion chamber 55. Since the flow of the exhaust gas is stable downstream of the expansion chamber 55, the influence of the pulsation of the exhaust gas in sensing can be suppressed as much as possible.

In the present embodiment, the connecting pipe 47 has a stay 51 connected to the body frame 12. The stay 51 is arranged in a direction opposite to the bulge of the expansion chamber 55 with respect to the vehicle width direction. Since the stay 51 is provided integrally with the connecting pipe 47, the number of parts is reduced. Further, since the stay 51 is arranged in the direction opposite to the bulge of the expansion chamber 55, it is possible to avoid applying a load to the bulge which is weak in design. The stay 51 may be connected to the engine 28 instead of the body frame 12.

The connecting pipe 47 is formed with a recess 66 in which the space occupied by the center stand 32 is arranged. In this way, since the recess 66 is formed in the connecting pipe 47, the interference between the connecting pipe 47 and the center stand 32 can be avoided.

In this embodiment, the expansion chamber 55 is hidden behind the catalyst 43 when the vehicle is viewed from the front. Therefore, the catalyst 43 can protect the expansion chamber 55 from pebbles flying from the front. Damage to the expansion chamber 55 can be prevented.

The first exhaust gas sensor 48 arranged upstream of the catalyst 43 is arranged below the engine 28. Since the first exhaust gas sensor 48 is held in a posture inclined from the vertical line 61, the catalyst 43 can be arranged at the highest position possible while avoiding the interference between the first exhaust gas sensor 48 and the engine 28. In this way, the minimum ground clearance can be secured.

In the present embodiment, the second exhaust gas sensor 49 is at a position that at least partially overlaps the brake pedal 59 in a vehicle side view. Since the second exhaust gas sensor 49 overlaps the brake pedal 59 when the vehicle is viewed from the side, the second exhaust gas sensor 49 can be protected by the brake pedal 59.

Claims (10)

Body frame (12),
An engine (28) suspended on the body frame (12);
A catalyst (43) arranged below the engine (28) for purifying exhaust gas emitted from the engine (28);
A silencer (45) arranged downstream of the catalyst (43) along the flow direction of the exhaust gas;
A downstream exhaust pipe (44) arranged downstream of the catalyst (43) along the flow direction and connected to the silencer (45) with a cross section smaller than the cross section of the catalyst (43);
A connecting pipe (47) sandwiched between the downstream exhaust pipe (44) and the catalyst (43) and having an expansion chamber (55) having a cross section larger than that of the catalyst (43);
A saddle-ride type vehicle comprising: The saddle-ride type vehicle according to claim 1, wherein the catalyst (43) is arranged at a position deviated to one side in the vehicle width direction from a central symmetry plane (SP) in the vehicle width direction of the vehicle body, and the expansion chamber (43). 55) is a saddle-ride type vehicle characterized by bulging in a direction opposite to the one. The saddle-ride type vehicle according to claim 1 or 2, wherein the engine (28) has an oil pan (53) arranged side by side with the catalyst (43) in a vehicle width direction, and the expansion chamber (55). ) Is a saddle-ride type vehicle characterized by expanding toward the space behind the oil pan (53). The saddle-ride type vehicle according to any one of claims 1 to 3, wherein the connecting pipe (47) is arranged in a space in front of the center stand (32). .. The saddle riding type vehicle according to any one of claims 1 to 4, wherein an exhaust gas sensor (49) is installed in the downstream exhaust pipe (44). The saddle-ride type vehicle according to any one of claims 1 to 5, wherein the connecting pipe (47) has a stay (51) connected to the vehicle body frame (12) or the engine (28), The saddle-ride type vehicle, wherein the stay (51) is arranged in a direction opposite to a bulge of the expansion chamber (55) with respect to a vehicle width direction. The saddle-ride type vehicle according to claim 4, wherein the connecting pipe (47) is formed with a recess (66) in which the space occupied by the center stand (32) is arranged. .. The saddle-ride type vehicle according to any one of claims 1 to 7, wherein the expansion chamber (55) is hidden behind the catalyst (43) in a vehicle front view. The saddle-ride type vehicle according to any one of claims 1 to 8, which is arranged upstream of the catalyst (43) along the flow direction and is inclined from a vertical line (61) defining a gravity direction. The saddle-ride type vehicle further comprising an exhaust gas sensor (48) held by the vehicle. The saddle riding type vehicle according to claim 5, wherein the exhaust gas sensor (49) is at a position at least partially overlapping the brake pedal (59) in a vehicle side view.

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