Saddle riding type vehicle

Abstract

To activate a catalyst at an early stage while suppressing influence on behavior of an engine in a saddle riding type vehicle.SOLUTION: A saddle riding type vehicle 1 includes an engine 14, a catalyst 39, wheels 5, a continuously variable transmission 15, a temperature sensor 104, and a controller 100. The temperature sensor 104 detects a temperature of the engine 14. The controller 100 controls the continuously variable transmission 15. The continuously variable transmission 15 is electrically controlled so as to change a speed ratio in accordance with a command signal from the controller 100. The controller 100 acquires the temperature of the engine 14. The controller 100 controls the speed ratio of the continuously variable transmission 15 so that, in low temperature time when the temperature of the engine 14 is equal to or lower than a prescribed first threshold temperature, an engine speed is higher than in normal time when the temperature of the engine 14 is higher than the first threshold temperature.SELECTED DRAWING: Figure 10

Description

[Technical Field]

[0001] The present invention relates to a saddle-ride type vehicle. [Background technology]

[0002] Some straddle-type vehicles are equipped with a catalyst for purifying exhaust gas from the engine. For example, the motorcycle disclosed in Patent Document 1 is equipped with an engine and an exhaust pipe connected to the engine. A catalyst is disposed inside the exhaust pipe. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2022-167313 Summary of the Invention [Problem to be solved by the invention]

[0004] When the engine temperature is low, such as immediately after starting the engine, catalyst activation is slow. To effectively purify exhaust gas, it is desirable to activate the catalyst quickly. Therefore, for example, when the engine temperature is low, it is conceivable to increase the throttle opening to increase the engine speed and thereby promote catalyst activation. However, this would affect engine behavior. The object of the present invention is to activate the catalyst quickly in a saddle-type vehicle while minimizing the impact on engine behavior. [Means for solving the problem]

[0005] A saddle-type vehicle according to one aspect of the present invention includes an engine, a catalyst, wheels, a continuously variable transmission, a temperature sensor, and a controller. The catalyst purifies exhaust gas from the engine. The continuously variable transmission transmits driving force from the engine to the wheels. The temperature sensor detects the temperature of the engine. The controller controls the continuously variable transmission. The continuously variable transmission is electrically controlled to change the gear ratio in response to a command signal from the controller. The controller acquires the engine temperature. The controller controls the gear ratio of the continuously variable transmission when the engine temperature is low, at or below a predetermined first threshold temperature, so that the engine rotation speed is higher than when the engine temperature is normally higher than the first threshold temperature.

[0006] In the saddle-ride type vehicle according to this aspect, the gear ratio of the continuously variable transmission is changed so that the engine rotation speed is increased compared to normal when the engine temperature is low. This increases the volume of exhaust gas even at low temperatures, promoting catalyst activity. Furthermore, the engine rotation speed is increased by electrically controlling the gear ratio of the continuously variable transmission. Therefore, the impact on engine behavior is reduced compared to when the engine rotation speed is increased by changing the throttle opening.

[0007] The engine may include a crankshaft. The continuously variable transmission may include a primary pulley, a secondary pulley, a belt, and an electric actuator. The primary pulley may include a first movable sheave and a first fixed sheave. The primary pulley may be connected to the crankshaft. The secondary pulley may include a second movable sheave and a second fixed sheave. The secondary pulley may be attached to a wheel. The belt may be wound around the primary pulley and the secondary pulley. The electric actuator may change the gear ratio of the continuously variable transmission by moving the first movable sheave relative to the first fixed sheave. The controller may control the electric actuator to change the gear ratio of the continuously variable transmission at low temperatures so that the engine rotation speed is higher than normal. In this case, the gear ratio of the continuously variable transmission is changed by controlling the electric actuator so that the engine rotation speed is higher than normal when the engine is at low temperatures.

[0008] The saddle-type vehicle may further include a vehicle speed sensor and a throttle sensor. The vehicle speed sensor may detect a vehicle speed of the saddle-type vehicle. The throttle sensor may detect a throttle opening of the engine. The controller may store normal state data and low temperature state data. The normal state data may define a relationship between a target engine rotation speed and a vehicle speed and a throttle opening under normal conditions. The low temperature state data may define a relationship between a target engine rotation speed and a vehicle speed and a throttle opening under low temperatures under low temperatures. The low temperature state data may define a target engine rotation speed that is at least partially higher than the normal state data for the same vehicle speed and the same throttle opening. The controller may determine the target engine rotation speed based on the normal state data under normal conditions. The controller may determine the target engine rotation speed based on the low temperature data under low temperatures. The controller may control the electric actuator to change the gear ratio of the continuously variable transmission so that the engine rotation speed becomes the target rotation speed. In this case, the engine speed at low temperatures is appropriately controlled according to the vehicle speed and throttle opening.

[0009] The low-temperature data may define a relationship between the target rotation speed and the vehicle speed and the throttle opening when the engine temperature is equal to or lower than a second threshold temperature that is lower than the first threshold temperature. When the engine temperature is between the first and second threshold temperatures, the controller may determine the target rotation speed by interpolation based on the normal data, the low-temperature data, and the engine temperature. In this case, the engine rotation speed at low temperatures is appropriately controlled according to the vehicle speed and the throttle opening.

[0010] When the throttle opening is a predetermined first opening, the low-temperature data may specify a target rotation speed higher than the normal data when the vehicle speed is between a predetermined first speed and a second speed higher than the first speed. In this case, when the throttle opening is the first opening and the vehicle speed is between the first speed and the second speed, the engine rotation speed is increased compared to normal when the engine temperature is low. This promotes catalyst activity even at low temperatures.

[0011] The saddle-ride type vehicle may further include a centrifugal clutch. The centrifugal clutch may be in an engaged state to connect the continuously variable transmission to the wheels when the vehicle speed is equal to or greater than an engaged speed. The engaged speed may be greater than a first speed. When the throttle opening is the first opening, the low-temperature data may specify the same target rotation speed as the normal data at vehicle speeds lower than the first speed. In this case, the engine rotation speed is prevented from increasing before the centrifugal clutch is engaged, thereby minimizing the impact on engine behavior.

[0012] When the throttle opening is the first opening, the low-temperature data may specify the same target rotation speed as the normal data at vehicle speeds higher than the second speed. When the vehicle speed is high, the engine rotation speed is high, so the volume of exhaust gas per unit time is large. This promotes catalyst activity and suppresses unnecessary increases in engine rotation speed.

[0013] When the throttle opening is a second opening greater than the first opening, the low-temperature data may specify the same target engine speed as the normal data, regardless of vehicle speed. When the throttle opening is large, the amount of fuel relative to the amount of intake air to the engine increases, resulting in increased heat output from the engine. This increases the volume of exhaust gas per engine cycle. This promotes catalyst activity and prevents unnecessary increases in engine speed.

[0014] The controller may determine a target rotation speed of the engine so that the engine rotation speed is higher at low temperatures than under normal conditions. The controller may determine a target gear ratio of the continuously variable transmission from the target rotation speed. The controller may control the electric actuator to change the gear ratio of the continuously variable transmission based on the target gear ratio. In this case, the gear ratio of the continuously variable transmission is changed based on the target gear ratio. As a result, the gear ratio of the continuously variable transmission is changed so that the engine rotation speed is higher at low temperatures than under normal conditions. [Effects of the Invention]

[0015] According to the present invention, in a straddle-type vehicle, it is possible to quickly activate a catalyst while minimizing the effect on engine behavior. [Brief explanation of the drawings]

[0016] [Figure 1] FIG. 2 is a left side view of the saddle-ride type vehicle. [Figure 2] FIG. 2 is a cross-sectional top view of the engine unit. [Figure 3] FIG. 2 is a right side view showing the engine unit and its surrounding structure. [Figure 4] FIG. 2 is an enlarged view showing a primary pulley and a sheave drive mechanism. [Figure 5] FIG. 2 is an enlarged view showing a primary pulley and a sheave drive mechanism. [Figure 6] FIG. 4 is an enlarged view showing a secondary pulley and a centrifugal clutch. [Figure 7] FIG. 4 is an enlarged view showing a secondary pulley and a centrifugal clutch. [Figure 8] 1 is a schematic diagram showing a control system of a continuously variable transmission in a saddle-ride type vehicle. [Figure 9] 4 is a flowchart showing a process for controlling the gear ratio of a continuously variable transmission. [Figure 10] FIG. 10 is a diagram illustrating an example of target rotation speed data. [Figure 11] FIG. 10 is a diagram illustrating an example of target rotation speed data. [Figure 12] FIG. 10 is a diagram illustrating an example of target rotation speed data. [Figure 13] FIG. 10 is a diagram showing an example of target sheave position data. DETAILED DESCRIPTION OF THE INVENTION

[0017] A saddle-riding vehicle according to an embodiment will now be described with reference to the drawings. FIG. 1 is a left side view of a saddle-riding vehicle 1 according to an embodiment. The saddle-riding vehicle 1 according to this embodiment is a scooter. As shown in FIG. 1, the saddle-riding vehicle 1 includes a body frame 2, a body cover 3, wheels 4 and 5, a steering device 6, a seat 7, and an engine unit 8. In this embodiment, the front-rear and left-right directions refer to the front-rear and left-right directions as seen from a rider seated on the seat 7.

[0018] The body cover 3 covers the body frame 2. The wheels 4, 5 include a front wheel 4 and a rear wheel 5. The steering device 6 is supported by the body frame 2 so as to be rotatable left and right. The steering device 6 includes a front fork 11, a steering shaft 12, and a handle member 13. The front fork 11 rotatably supports the front wheel 4. The steering shaft 12 is connected to the front fork 11. The steering shaft 12 is supported by the body frame 2 so as to be rotatable left and right. The handle member 13 is connected to the steering shaft 12.

[0019] The seat 7 is disposed behind the handle member 13. The engine unit 8 is disposed below the seat 7. The engine unit 8 is supported by the body frame 2 so as to be able to swing up and down. The rear wheel 5 is rotatably supported by the engine unit 8. The engine unit 8 includes an engine 14 and a continuously variable transmission 15. The continuously variable transmission 15 is disposed to the side of the engine 14. The continuously variable transmission 15 transmits driving force from the engine 14 to the rear wheel 5.

[0020] FIG. 2 is a cross-sectional top view of the engine unit 8. As shown in FIG. 2, the engine 14 includes a crankcase 21, a crankshaft 22, a cylinder body 23, a cylinder head 24, a piston 25, a connecting rod 26, and a valve train 27. The crankshaft 22 is accommodated in the crankcase 21. The crankshaft 22 is rotatably supported by the crankcase 21 via bearings 28 and 29. The crankshaft 22 includes a first shaft end 22A and a second shaft end 22B. The continuously variable transmission 15 is connected to the first shaft end 22A. The generator 31 is connected to the second shaft end 22B.

[0021] The cylinder body 23 is connected to the crankcase 21. The cylinder head 24 is connected to the cylinder body 23. A connecting rod 26 and a piston 25 are disposed within the cylinder body 23. The piston 25 is connected to the crankshaft 22 via the connecting rod 26. An ignition device 32 is attached to the cylinder head 24. The valve train 27 includes a camshaft 33. A cam chain 34 is wound around the camshaft 33 and the crankshaft 22. The rotation of the crankshaft 22 is transmitted to the camshaft 33 via the cam chain 34, causing the camshaft 33 to rotate. As a result, intake valves and exhaust valves (not shown) of the engine 14 are driven by the valve train 27.

[0022] FIG. 3 is a right side view showing the engine unit 8 and its surrounding structure. As shown in FIG. 3, the saddle-riding vehicle 1 includes a radiator 35 and a radiator cover 36. The radiator 35 cools the coolant for the engine 14. The radiator cover 36 covers the radiator 35. The saddle-riding vehicle 1 is equipped with an exhaust pipe 37, a silencer 38, and a catalyst 39. The exhaust pipe 37 is connected to the cylinder head 24 of the engine 14. The silencer 38 is connected to the exhaust pipe 37. The catalyst 39 is provided midway through the exhaust pipe 37. The catalyst 39 is, for example, a three-way catalyst. The catalyst 39 purifies the exhaust from the engine 14.

[0023] The continuously variable transmission 15 shown in Fig. 2 is an electronically controlled transmission. That is, the continuously variable transmission 15 is electrically controlled to change the gear ratio in response to a command signal from a controller (described later). As shown in Fig. 2, the continuously variable transmission 15 includes a primary pulley 41, a secondary pulley 42, a belt 43, a sheave drive mechanism 44, a centrifugal clutch 45, an output shaft 46, a reducer 47, and a transmission case 48.

[0024] The primary pulley 41 is connected to the crankshaft 22. The primary pulley 41 includes a V-shaped first groove 41A. The secondary pulley 42 is connected to the rear wheel 5 via an axle 49. The secondary pulley 42 includes a V-shaped second groove 42A. The belt 43 is wound around the primary pulley 41 and the secondary pulley 42. The belt 43 has a trapezoidal cross section corresponding to the shapes of the first groove 41A and the second groove 42A. The secondary pulley 42 is connected to the output shaft 46 via a centrifugal clutch 45. The output shaft 46 is connected to the axle 49 via a reducer 47.

[0025] The reducer 47 includes a reducer case 51 and a gear 52. The reducer case 51 houses the gear 52. The output shaft 46 is rotatably supported by the reducer case 51 via bearings 53 and 54. The axle 49 is rotatably supported by the reducer case 51 via bearings 55 and 56. The gear 52 transmits the rotation of the output shaft 46 to the axle 49. Note that in FIG. 2 , only the gear 52 of the multiple gears of the reducer 47 is shown, and the other gears are omitted. The transmission case 48 axially covers the primary pulley 41, the secondary pulley 42, the belt 43, the centrifugal clutch 45, and the output shaft 46.

[0026] FIG. 4 is an enlarged view showing the primary pulley 41 and the sheave drive mechanism 44. As shown in FIG. 4, the primary pulley 41 includes a first moving sheave 57 and a first fixed sheave 58. The first moving sheave 57 is supported relative to the crankshaft 22 so as to be movable in the axial direction of the crankshaft 22 (hereinafter simply referred to as the axial direction). The first moving sheave 57 is disposed axially inside (on the left side in FIG. 4) the first fixed sheave 58. The first moving sheave 57 is supported relative to the crankshaft 22 so as not to be rotatable in the circumferential direction of the crankshaft 22. For example, the first moving sheave 57 is fixed to the crankshaft 22 by a spline. The first moving sheave 57 rotates integrally with the crankshaft 22.

[0027] The first movable sheave 57 includes a first sheave portion 59 and a first boss portion 60. The first sheave portion 59 is disposed opposite the first fixed sheave 58. A first groove 41A is provided between the first sheave portion 59 and the first fixed sheave 58. The first boss portion 60 extends in the axial direction from the first sheave portion 59. The first boss portion 60 includes a first boss hole 61. The first boss hole 61 extends axially through the first boss portion 60. The crankshaft 22 extends through the first boss hole 61.

[0028] The crankshaft 22 includes an outer shaft 62. The outer shaft 62 is attached to the outer peripheral surface of the first shaft end 22A. The first movable sheave 57 is fixed to the outer shaft 62 by a spline. The outer shaft 62 extends through a first boss hole 61. A first bushing 63 and a second bushing 64 are press-fitted into the first boss hole 61. The first bushing 63 and the second bushing 64 are made of a sliding material. The first bushing 63 and the second bushing 64 are disposed between the inner peripheral surface of the first boss hole 61 and the outer peripheral surface of the outer shaft 62. As the first movable sheave 57 moves in the axial direction, the first bushing 63 and the second bushing 64 slide axially relative to the outer shaft 62. The first boss hole 61 is filled with a lubricant such as grease. The gap between the first boss portion 60 and the outer shaft 62 is sealed by oil seals 65 and 66.

[0029] The first fixed sheave 58 is fixed to the crankshaft 22. The first fixed sheave 58 is fixed to the crankshaft 22 by a nut 40. The first fixed sheave 58 is fixed to the crankshaft 22 so as to be immovable in the axial direction. The first fixed sheave 58 is fixed to the crankshaft 22 so as to be imrotatable relative to the crankshaft 22. The first fixed sheave 58 rotates integrally with the crankshaft 22.

[0030] The sheave drive mechanism 44 moves the first movable sheave 57 in the axial direction. As shown in FIG. 2, the sheave drive mechanism 44 includes an electric actuator 67, a first drive member 68, and a second drive member 69. The electric actuator 67 is, for example, an electric motor. However, the electric actuator 67 may be an actuator other than an electric motor. The electric actuator 67 includes a rotating shaft 70. The rotating shaft 70 is connected to the first drive member 68 via a gear 71. The rotation of the rotating shaft 70 is transmitted to the first drive member 68 via the gear 71.

[0031] As shown in Figure 4, the first drive member 68 includes a first bore 72. The first bore 72 extends axially through the first drive member 68. The crankshaft 22 extends through the first bore 72. The first drive member 68 is supported on the crankshaft 22 via a bearing 50. The first drive member 68 is supported rotatably relative to the crankshaft 22. The first drive member 68 is supported so as to be immovable in the axial direction relative to the crankshaft 22.

[0032] The first driving member 68 includes a gear portion 73 and a feed screw portion 74. The gear portion 73 extends from the feed screw portion 74 in the radial direction of the crankshaft 22. The gear portion 73 meshes with a gear 71. The rotation of the rotary shaft 70 of the electric actuator 67 is transmitted to the gear portion 73 via the gear 71. This causes the first driving member 68 to rotate. The feed screw portion 74 extends in the axial direction from the gear portion 73. A first screw 75 is provided on the outer circumferential surface of the feed screw portion 74.

[0033] A crankcase cover 76 is attached to the crankcase 21. The crankcase cover 76 includes an opening 76A. The opening 76A is disposed facing the primary pulley 41. The second drive member 69 extends through the opening 76A of the crankcase 21. An oil seal 77 seals between the second drive member 69 and the crankcase cover 76. The second drive member 69 includes a second hole 78. The second hole 78 extends axially through the second drive member 69. The crankshaft 22 and the first boss portion 60 extend through the second hole 78.

[0034] The second drive member 69 is supported by the first boss portion 60 via a bearing 79. The second drive member 69 is rotatably supported by the first boss portion 60. The second drive member 69 is supported by the first boss portion 60 so as to be immovable in the axial direction. The second drive member 69 moves axially together with the first movable sheave 57. An oil seal 80 seals the gap between the second drive member 69 and the first boss portion 60. A second screw 81 is provided on the inner circumferential surface of the second drive member 69. The second screw 81 is engaged with the first screw 75. When the first drive member 68 rotates, the second drive member 69 moves axially as shown in FIG. 5. This causes the first movable sheave 57 to move axially.

[0035] FIG. 6 is an enlarged view showing the secondary pulley 42 and the centrifugal clutch 45. As shown in FIG. 6, the secondary pulley 42 includes a second fixed sheave 82 and a second movable sheave 83. The second fixed sheave 82 is rotatably supported on the output shaft 46. The second fixed sheave 82 is supported on the output shaft 46 so as to be immovable in the axial direction. The second fixed sheave 82 includes a second sheave portion 84 and a second boss portion 85. The second sheave portion 84 is disposed opposite the second movable sheave 83. A second groove 42A is provided between the second sheave portion 84 and the second movable sheave 83. The second boss portion 85 extends in the axial direction from the second sheave portion 84. The second boss portion 85 includes a second boss hole 86. The second boss hole 86 extends in the axial direction through the second boss portion 85.

[0036] The output shaft 46 is rotatably supported by the transmission case 48 via a bearing 95. The output shaft 46 extends through a second boss hole 86. A bushing 91 is press-fitted into the second boss hole 86. The bushing 91 is made of a sliding material. The bushing 91 is disposed between the inner peripheral surface of the second boss hole 86 and the outer peripheral surface of the output shaft 46. The second boss portion 85 is rotatably supported on the output shaft 46 by the bushing 91 and a bearing 92. The second boss hole 86 is filled with a lubricant such as grease. An oil seal 93 seals the gap between the second boss portion 85 and the output shaft 46.

[0037] The second movable sheave 83 is disposed axially outward (to the right in FIG. 6) relative to the second fixed sheave 82. The second movable sheave 83 is supported non-rotatably relative to the second boss portion 85. The second movable sheave 83 rotates integrally with the second fixed sheave 82. The second movable sheave 83 is supported axially movably relative to the second boss portion 85. For example, the second movable sheave 83 is fixed to the second boss portion 85 by a spline. A spring 87 is disposed between the second movable sheave 83 and the centrifugal clutch 45. The spring 87 biases the second movable sheave 83 toward the second fixed sheave 82.

[0038] As shown in Figure 6, when the vehicle speed is lower than a predetermined connecting speed, the centrifugal clutch 45 is in a disengaged state that disconnects the continuously variable transmission 15 from the rear wheels 5. As shown in Figure 7, when the vehicle speed is equal to or higher than the connecting speed, the centrifugal clutch 45 is in an engaged state that connects the continuously variable transmission 15 to the rear wheels 5. The centrifugal clutch 45 includes a drive plate 88, a clutch shoe 89, and a clutch outer 90.

[0039] The drive plate 88 is fixed to the second boss portion 85. The drive plate 88 rotates integrally with the second boss portion 85. The clutch shoe 89 is connected to the drive plate 88. The clutch shoe 89 rotates integrally with the drive plate 88. The clutch shoe 89 is supported so as to be movable radially relative to the drive plate 88. The clutch shoe 89 is biased radially inward by a clutch spring (not shown). The clutch outer 90 is fixed to the output shaft 46 by a nut 94. The clutch outer 90 rotates integrally with the output shaft 46. The clutch outer 90 covers the clutch shoe 89 in the radial direction.

[0040] When the vehicle speed is slower than a predetermined engagement speed, the clutch shoe 89 is separated from the clutch outer 90 by the biasing force of the clutch spring. Therefore, the centrifugal clutch 45 is in a disengaged state, and the rotation of the secondary pulley 42 is not transmitted to the output shaft 46. When the vehicle speed is equal to or higher than the engagement speed, the clutch shoe 89 moves radially outward against the biasing force of the clutch spring due to centrifugal force. As a result, the clutch shoe 89 comes into contact with the clutch outer 90, and the centrifugal clutch 45 enters an engaged state. When the centrifugal clutch 45 is in an engaged state, the rotation of the secondary pulley 42 is transmitted to the output shaft 46 via the drive plate 88, the clutch shoe 89, and the clutch outer 90.

[0041] In the continuously variable transmission 15 described above, when the vehicle speed is equal to or higher than the coupling speed, the centrifugal clutch 45 is engaged. As a result, the rotation of the crankshaft 22 is transmitted to the rear wheel 5 via the primary pulley 41, the belt 43, the secondary pulley 42, the centrifugal clutch 45, the output shaft 46, the reducer 47, and the axle 49. As a result, the saddle-type vehicle 1 travels.

[0042] Furthermore, the gear ratio of the continuously variable transmission 15 is electrically controlled by moving the first movable sheave 57 with the sheave drive mechanism 44. The gear ratio of the continuously variable transmission 15 means the ratio of the rotational speed of the crankshaft 22 to the rotational speed of the output shaft 46.

[0043] Specifically, when the electric actuator 67 rotates the first driving member 68 in a certain direction, the second driving member 69 moves axially outward, as shown in FIG. 5. This causes the first movable sheave 57 to move axially outward together with the second driving member 69. When the first movable sheave 57 moves axially outward, the width of the first groove 41A between the first movable sheave 57 and the first fixed sheave 58 decreases. This increases the diameter of the portion of the belt 43 wound around the primary pulley 41 (hereinafter referred to as the first winding diameter). When the first winding diameter increases, the diameter of the portion of the belt 43 wound around the secondary pulley 42 (hereinafter referred to as the second winding diameter) decreases. This decreases the gear ratio. In this case, as shown in FIG. 7, the second movable sheave 83 moves axially outward against the biasing force of the spring 87, and the width of the second groove 42A increases.

[0044] When the electric actuator 67 rotates the first drive member 68 in the reverse direction, the second drive member 69 moves axially inward, as shown in FIG. 4. As a result, the first movable sheave 57 moves axially inward together with the second drive member 69. When the first movable sheave 57 moves axially inward, the width of the first groove 41A between the first movable sheave 57 and the first fixed sheave 58 increases. This reduces the first winding diameter. When the first winding diameter decreases, the second winding diameter increases. This increases the gear ratio. In this case, as shown in FIG. 6, the second movable sheave 83 moves axially inward due to the biasing force of the spring 87, and the width of the second groove 42A decreases.

[0045] Next, control of the gear ratio of the continuously variable transmission 15 in the saddle-riding vehicle 1 will be described. FIG. 8 is a schematic diagram showing a control system of the continuously variable transmission 15 in the saddle-riding vehicle 1. As shown in FIG. 8, the saddle-riding vehicle 1 includes a controller 100, a vehicle speed sensor 101, a throttle sensor 102, a sheave position sensor 103, and a temperature sensor 104. The controller 100 includes a processor 105 and a storage device 106. The processor 105 is, for example, a CPU, and executes processing for controlling the gear ratio of the continuously variable transmission 15. The storage device 106 includes memories such as RAM and ROM. The storage device 106 may also include an auxiliary storage device such as an HDD or SSD. The storage device 106 stores programs and data for controlling the gear ratio of the continuously variable transmission 15.

[0046] The vehicle speed sensor 101 detects the vehicle speed of the saddle riding type vehicle 1. The vehicle speed sensor 101 detects, for example, the rotational speed of the axle 49. The vehicle speed sensor 101 outputs a signal indicating the vehicle speed to the controller 100. The throttle sensor 102 detects the throttle opening of the engine 14. The throttle sensor 102 outputs a signal indicating the throttle opening of the engine 14 to the controller 100. The throttle opening of the engine 14 is changed in response to the rider's operation of the accelerator. The temperature sensor 104 detects the temperature of the engine 14. The temperature sensor 104 detects, for example, the temperature of the coolant of the engine 14. The temperature sensor 104 outputs a signal indicating the temperature of the engine 14 to the controller 100.

[0047] The controller 100 is communicably connected to the above-mentioned sensors 101-104. The controller 100 controls the electric actuator 67 based on signals from the above-mentioned sensors 101-104, thereby controlling the gear ratio of the continuously variable transmission 15. Figure 9 is a flowchart showing a process for controlling the gear ratio of the continuously variable transmission 15.

[0048] As shown in FIG. 9, in step S101, the controller 100 acquires the vehicle speed. The controller 100 acquires the vehicle speed based on a signal from the vehicle speed sensor 101. In step S102, the controller 100 acquires the throttle opening based on a signal from the throttle sensor 102. In step S103, the controller 100 acquires the temperature of the engine 14 based on a signal from the temperature sensor 104.

[0049] In step S104, the controller 100 determines a target rotation speed of the engine 14. The controller 100 determines the target rotation speed of the engine 14 based on the vehicle speed and the throttle opening. The target rotation speed data D1 defines the relationship between the vehicle speed, the throttle opening, and the target rotation speed of the engine 14.

[0050] 10 to 12 are diagrams showing an example of target rotation speed data D1. In FIGS. 10 to 12, the horizontal axis represents vehicle speed, and the vertical axis represents the target rotation speed of the engine 14. Also, FIGS. 10 to 12 show target rotation speed data D1 for different throttle openings. The target rotation speed data D1 shown in FIG. 10 represents the target rotation speed data D1 when the throttle opening is a first opening. The target rotation speed data D1 shown in FIG. 11 represents the target rotation speed data D1 when the throttle opening is a second opening that is larger than the first opening. The target rotation speed data D1 shown in FIG. 12 represents the target rotation speed data D1 when the throttle opening is a third opening between the first opening and the second opening.

[0051] 10 to 12, the target rotation speed data D1 includes normal state data D2 and low temperature data D3. When the temperature of the engine 14 is higher than a predetermined first threshold temperature, the controller 100 refers to the normal state data D2 and determines the target rotation speed of the engine 14 based on the vehicle speed and the throttle opening. When the temperature of the engine 14 is equal to or lower than the first threshold temperature, the controller 100 refers to the low temperature data D3 and determines the target rotation speed of the engine 14 based on the vehicle speed and the throttle opening.

[0052] Specifically, the controller 100 stores normal data D2 and reference low temperature data D3. When the engine temperature is equal to or lower than a second threshold temperature that is lower than the first threshold temperature, the controller 100 refers to the reference low temperature data D3 and determines the target rotation speed of the engine 14 based on the vehicle speed and the throttle opening.

[0053] When the temperature of the engine 14 is between the first threshold temperature and the second threshold temperature, the controller 100 determines the target rotation speed by interpolation based on the normal data D2, the reference low temperature data D3, and the temperature of the engine 14. For example, the controller 100 calculates the low temperature data D3 at a temperature between the first threshold temperature and the second threshold temperature by multiplying the reference low temperature data D3 by a predetermined reflection rate. The reflection rate increases as the temperature between the first threshold temperature and the second threshold temperature decreases. The controller 100 then determines the target rotation speed of the engine 14 based on the vehicle speed and the throttle opening degree, with reference to the low temperature data D3 calculated by interpolation.

[0054] For example, if the temperature of the engine 14 is equal to or higher than the first threshold temperature, in step S104, the controller 100 determines the target rotation speed of the engine 14 based on the vehicle speed and the throttle opening degree, with reference to the normal state data D2 shown in Figures 10 to 12.

[0055] In step S105, the controller 100 determines the target gear ratio. The controller 100 calculates the target gear ratio from the target engine rotation speed.

[0056] In step S106, the controller 100 determines a target sheave position. The gear ratio of the continuously variable transmission 15 is determined according to the position of the first movable sheave 57. The controller 100 determines the target sheave position based on the target gear ratio. Specifically, the controller 100 stores target sheave position data D4. The target sheave position data D4 defines the relationship between the target gear ratio and the target sheave position. Figure 13 is a diagram showing an example of the target sheave position data D4. The target sheave position indicates the distance from a predetermined reference position.

[0057] For example, the target sheave position increases from the reference position toward the outside in the axial direction. As shown in FIG. 13, the larger the target speed ratio, the smaller the target sheave position. In other words, the larger the target speed ratio, the more the target sheave position moves toward the inside in the axial direction. The smaller the target speed ratio, the larger the target sheave position. In other words, the larger the target speed ratio, the more the target sheave position moves toward the outside in the axial direction.

[0058] In step S107, the controller 100 controls the electric actuator 67 to move the first movable sheave 57 to the target sheave position, thereby changing the gear ratio of the continuously variable transmission 15 so that the rotation speed of the engine 14 becomes the target rotation speed.

[0059] If the temperature of the engine 14 is equal to or lower than the first threshold temperature, in step S104, the controller 100 refers to the low-temperature data D3 and determines a target rotation speed of the engine 14. The low-temperature data D3 defines a target rotation speed of the engine 14 that is higher than the normal data D2 at least in part for the same vehicle speed and the same throttle opening. Therefore, when the temperature of the engine 14 is low, that is, equal to or lower than the first threshold temperature, the controller 100 determines the target rotation speed of the engine 14 and controls the gear ratio of the continuously variable transmission 15 so that the engine rotation speed is higher than that in normal conditions.

[0060] 10, when the throttle opening is a predetermined first opening, the low temperature data D3 defines a target rotation speed higher than that of the normal data D2 at vehicle speeds ranging from a predetermined first speed V1 to a second speed V2 that is greater than the first speed V1. When the throttle opening is the first opening, the low temperature data D3 defines the same target rotation speed as the normal data D2 at vehicle speeds less than the first speed V1. The first speed V1 is less than the engagement speed of the centrifugal clutch 45 described above. When the throttle opening is the first opening, the low temperature data D3 defines the same target rotation speed as the normal data D2 at vehicle speeds greater than the second speed V2.

[0061] As shown in Fig. 12, when the throttle opening is a third opening between the first and second openings, the low-temperature data D3 defines a target rotation speed higher than that of the normal data D2 at vehicle speeds from a predetermined third speed V3 to a fourth speed V4 greater than the third speed V3. When the throttle opening is the third opening, the low-temperature data D3 defines the same target rotation speed as the normal data D2 at vehicle speeds lower than the third speed V3. The third speed V3 is lower than the engagement speed of the centrifugal clutch 45 described above. When the throttle opening is the third opening, the low-temperature data D3 defines the same target rotation speed as the normal data D2 at vehicle speeds higher than the fourth speed V4.

[0062] As shown in FIG. 11, when the throttle opening is the second opening, the low temperature data D3 defines the same target rotation speed as the normal data D2, regardless of the vehicle speed.

[0063] In the saddle-ride type vehicle 1 according to the present embodiment described above, when the temperature of the engine 14 is low, the gear ratio of the continuously variable transmission 15 is changed so that the engine rotation speed is higher than normal. This increases the volume of exhaust gas even at low temperatures, promoting the activity of the catalyst 39. Furthermore, the engine rotation speed is increased by electrically controlling the gear ratio of the continuously variable transmission 15. Therefore, the effect on the behavior of the engine 14 is reduced compared to when the engine rotation speed is increased by changing the throttle opening.

[0064] Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and various modifications are possible without departing from the gist of the invention.

[0065] The straddle-type vehicle 1 is not limited to a scooter, but may be other types of vehicles such as a street type, an off-road type, or a moped. The configuration of the continuously variable transmission 15 is not limited to that of the above embodiment and may be modified. The process for controlling the gear ratio of the continuously variable transmission 15 is not limited to that of the above embodiment and may be modified. [Industrial Applicability]

[0066] According to the present invention, in a straddle-type vehicle, it is possible to quickly activate a catalyst while minimizing the effect on engine behavior. [Explanation of symbols]

[0067] 5: rear wheel, 14: engine, 15: continuously variable transmission, 22: crankshaft, 39: catalyst, 41: primary pulley, 42: secondary pulley, 43: belt, 45: centrifugal clutch, 57: first moving sheave, 58: first fixed sheave, 67: electric actuator, 82: second fixed sheave, 83: second moving sheave, 100: controller, 101: vehicle speed sensor, 102: throttle sensor, 104: temperature sensor

Claims

1. The engine and a catalyst for purifying exhaust gas from the engine; Wheels and a continuously variable transmission that transmits driving force from the engine to the wheels; a temperature sensor for detecting the temperature of the engine; a controller that controls the continuously variable transmission; Equipped with the continuously variable transmission is electrically controlled to change the gear ratio in response to a command signal from the controller; The controller acquiring the temperature of the engine; When the temperature of the engine is low and equal to or lower than a predetermined first threshold temperature, the gear ratio of the continuously variable transmission is controlled so that the engine rotation speed is increased compared to when the temperature of the engine is normally higher than the first threshold temperature. Saddle-type vehicle.

2. the engine includes a crankshaft; The continuously variable transmission is a primary pulley including a first movable sheave and a first fixed sheave and connected to the crankshaft; a secondary pulley including a second movable sheave and a second fixed sheave and attached to the wheel; a belt wound around the primary pulley and the secondary pulley; an electric actuator that changes the gear ratio of the continuously variable transmission by moving a first movable sheave relative to the first fixed sheave; Including, the controller controls the electric actuator to change the gear ratio of the continuously variable transmission so that the engine rotation speed is increased at the low temperature compared to the normal time. The saddle-type vehicle according to claim 1 .

3. a vehicle speed sensor for detecting a vehicle speed of the saddle-ride type vehicle; a throttle sensor that detects a throttle opening of the engine; Furthermore, the controller stores normal time data defining a relationship between the vehicle speed and the throttle opening and the target rotation speed of the engine during the normal time, and low temperature time data defining a relationship between the vehicle speed and the throttle opening and the target rotation speed of the engine during the low temperature time, the low-temperature data defines, at least in part, a target rotation speed for the engine that is higher than the normal-temperature data for a given vehicle speed and a given throttle opening; The controller During the normal operation, a target rotation speed of the engine is determined based on the normal operation data; determining a target rotation speed of the engine based on the low temperature data when the temperature is low; controlling the electric actuator to change the gear ratio of the continuously variable transmission so that the engine rotation speed becomes the target rotation speed; The straddle-type vehicle according to claim 2.

4. the low-temperature data defines a relationship between the target rotation speed and the vehicle speed and the throttle opening at a temperature equal to or lower than a second threshold temperature that is lower than the first threshold temperature; when the engine temperature is between the first threshold temperature and the second threshold temperature, the controller determines the target rotation speed by interpolation based on the normal data, the low temperature data, and the engine temperature; The straddle-type vehicle according to claim 3.

5. When the throttle opening is a predetermined first opening, the low-temperature data defines the target rotation speed higher than that of the normal-time data at a vehicle speed ranging from a predetermined first speed to a second speed higher than the first speed. The straddle-type vehicle according to claim 3.

6. a centrifugal clutch that is engaged to connect the continuously variable transmission to the wheels when the vehicle speed is equal to or greater than a connecting speed; the coupling speed is greater than the first speed; When the throttle opening is the first opening, the low-temperature data defines the same target rotation speed as the normal-time data at a vehicle speed lower than the first speed.

6. The straddle-type vehicle according to claim 5.

7. When the throttle opening is the first opening, the low-temperature data defines the same target rotation speed as the normal-time data at a vehicle speed higher than the second speed.

6. The straddle-type vehicle according to claim 5.

8. When the throttle opening is a second opening that is greater than the first opening, the low-temperature data defines the same target rotation speed as the normal data, regardless of the vehicle speed.

6. The straddle-type vehicle according to claim 5.

9. The controller determining a target rotation speed of the engine so that the engine rotation speed is increased at the low temperature compared to the normal temperature; determining a target speed ratio of the continuously variable transmission from the target rotational speed; controlling the electric actuator to change the gear ratio of the continuously variable transmission based on the target gear ratio; The straddle-type vehicle according to claim 2.

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