Saddle-riding type electric vehicle

Abstract

The present invention realizes a saddle-riding type electric vehicle capable of reducing loss of power due to compression of air in a cylinder, while generating intake sound, exhaust sound, and vibrations similar to those of a reciprocating engine by means of the power of a motor that drives a driving wheel. A saddle-riding type electric vehicle 1 has: a crankshaft 16 configured to reciprocate a piston 14 between a first position P1 and a second position P2, which is located farther from a cylinder head 12 than the first position P1, and to transmit power to a rear wheel 7; an intake valve 17; an exhaust valve 18; and a motor 19 that rotates the crankshaft 16. The degree of opening of the intake valve 17 is adjusted so that air passes through an intake port in a second stroke S2 in which the piston 14 moved to the first position P1 moves to the second position P2. The degree of opening of the exhaust valve 18 is adjusted so that air passes through an exhaust port in a first stroke S1, the second stroke S2, a third stroke S3, and a fourth stroke S4.

Description

Saddle-type electric vehicle

[0001] The present invention relates to a straddle-type electric vehicle.

[0002] A four-stroke reciprocating engine generates power by burning a mixture of air and fossil fuel such as gasoline in its cylinders, producing intake noise, exhaust noise, vibrations, etc. during each of the intake, compression, explosion, and exhaust strokes. Drivers of saddle-type vehicles powered by a reciprocating engine feel a sense of excitement when they experience the sounds and vibrations that occur in response to their accelerator operation.

[0003] On the other hand, saddle-type electric vehicles, which use a motor as a power source, do not burn gasoline or the like, and therefore do not produce the intake noise, exhaust noise, vibration, etc. that conventional reciprocating engines produce. Therefore, while some saddle-type vehicle enthusiasts support the reduction of carbon dioxide emissions, they have desired to drive a saddle-type vehicle that allows them to experience the unique sounds and vibrations of a reciprocating engine.

[0004] Therefore, a vehicle drive motor that has an appearance similar to that of a conventional reciprocating engine has been disclosed. The vehicle drive motor described in Patent Document 1 rotates a crankshaft by reciprocating a piston (linear motor slider) in a cylinder using a linear motor. The vehicle drive motor is configured to take in air through an intake valve and exhaust air through an exhaust valve as the piston reciprocates.

[0005] Japanese Patent Application Publication No. 08-065997

[0006] The vehicle drive motor described in Patent Document 1 reproduces the intake sound, exhaust sound, and vibration generated by a reciprocating engine by the reciprocating motion of a piston, the rotational motion of a crankshaft, intake through an intake valve, and exhaust through an exhaust valve. The vehicle drive motor compresses air in a cylinder using a piston to generate the intake sound and exhaust sound. During this process, a portion of the power output from the vehicle drive motor is used to compress the air and is not transmitted to the drive wheels of the vehicle. Therefore, Patent Document 1 discloses a configuration in which the entire top surface of the piston is open to reduce power loss caused by compressing the air in the cylinder.

[0007] However, a vehicle drive motor with an open ceiling surface of the piston does not produce the intake and exhaust sounds of a conventional reciprocating engine. In other words, a configuration with an open ceiling surface does not allow for the reproduction of intake and exhaust sounds. Therefore, the technology of Patent Document 1 cannot simultaneously reproduce intake and exhaust sounds and vibrations while suppressing power loss due to compressing the air in the cylinder. Furthermore, Patent Document 1 does not describe or suggest how to simultaneously reproduce intake and exhaust sounds and vibrations while suppressing power loss due to compressing the air in the cylinder. Therefore, there has been a demand for a saddle-type electric vehicle that can generate intake and exhaust sounds and vibrations using the power of the vehicle drive motor while reducing power loss due to compressing the air in the cylinder.

[0008] The present invention aims to provide a saddle-type electric vehicle that can reduce the power loss caused by compressing air in the cylinder while generating intake noise, exhaust noise, and vibrations similar to those of a reciprocating engine using the power of a motor that drives the drive wheels.

[0009] The inventors have studied a straddle-type electric vehicle that can reduce the loss of power caused by compressing air in a cylinder while generating intake noise, exhaust noise, and vibrations similar to those of a reciprocating engine using the power of a motor that drives the drive wheels. As a result of extensive research, the inventors have come up with the following configuration.

[0010] a power source that supplies power to the motor; and a power source that supplies power to the motor. The power source includes a motor, at least one cylinder, a cylinder head that is connected to an axial end of the cylinder and has an intake port and an exhaust port that communicate with the interior of the cylinder, a piston that is located within the cylinder and moves back and forth in the axial direction of the cylinder, an intake valve whose opening is adjusted to adjust the amount of air that passes through the intake port, and an exhaust valve whose opening is adjusted to adjust the amount of air that passes through the exhaust port. The motor rotates the piston around its axis to move the piston back and forth between a first position within the cylinder and a second position that is farther from the cylinder head than the first position, and the crankshaft is configured to transmit power of the motor to drive wheels while adjusting the openings of the intake valve and the exhaust valve.

[0011] The saddle-type electric vehicle, by rotation of the crankshaft, sequentially repeats the following: a first stroke in which the piston is moved from the second position to the first position, a second stroke in which the piston, which was moved to the first position in the first stroke, is moved to the second position, a third stroke in which the piston, which was moved to the second position in the second stroke, is moved to the first position, and a fourth stroke in which the piston, which was moved to the first position in the third stroke, is moved to the second position. In the second stroke, the crankshaft adjusts the opening of an intake valve so that air passes through the intake hole, and in the first stroke, the second stroke, the third stroke, and the fourth stroke, adjusts the opening of an exhaust valve so that air passes through the exhaust hole.

[0012] The saddle-type electric vehicle of the present application is not equipped with a reciprocating engine, but is configured as an electric vehicle in which the power of the motor is transmitted to the drive wheels by rotating a crankshaft about an axis line by the motor. In the saddle-type electric vehicle, the power of the motor is transmitted to the drive wheels via the crankshaft, and the piston in the cylinder is reciprocated by the crankshaft.

[0013] The saddle-type electric vehicle draws outside air into the cylinder through at least an intake port during a second stroke, which corresponds to the intake stroke of a reciprocating engine. That is, the saddle-type electric vehicle generates an intake noise at least once during the second stroke during four cycles from the first stroke to the fourth stroke.

[0014] The straddle-type electric vehicle exhausts air from the cylinder to the outside through at least the exhaust port during a first stroke corresponding to the exhaust stroke of a reciprocating engine and a third stroke corresponding to the compression stroke of the reciprocating engine, generating an exhaust sound.

[0015] Furthermore, the saddle-riding type electric vehicle generates vibrations due to the reciprocating motion of the piston and the rotational motion of the crankshaft between the first stroke and the fourth stroke. That is, the saddle-riding type electric vehicle generates vibrations twice during the four cycles from the first stroke to the fourth stroke. Also, the saddle-riding type electric vehicle suppresses compression of air in the cylinder by adjusting the opening of the exhaust valve so that air passes through the exhaust port during the first stroke and the third stroke.

[0016] Therefore, the power of the motor that drives the drive wheels can reduce the power loss caused by compressing the air in the cylinder while generating intake noise, exhaust noise, and vibrations similar to those of a reciprocating engine.

[0017] From another viewpoint, it is preferable that the saddle-type electric vehicle of the present invention includes the following configuration: in the second stroke, the crankshaft adjusts the opening degree of the intake valve to a first opening degree and adjusts the opening degree of the exhaust valve to a second opening degree that is smaller than the first opening degree.

[0018] As described above, the saddle-riding type electric vehicle adjusts the opening of the intake valve so that the first opening is greater than the second opening of the exhaust valve during the second stroke of the piston. At this time, the amount of air taken in per unit time through the intake port is greater than the amount of air taken in per unit time through the exhaust port. Therefore, during the second stroke of the piston, the saddle-riding type electric vehicle generates intake noise, which is mainly caused by air being taken into the cylinder through the intake port.

[0019] In this way, in the saddle-riding type electric vehicle, the opening degrees of the intake valve and the exhaust valve are set so that the intake sound is emphasized in the second stroke, which corresponds to the intake stroke of a reciprocating engine. In other words, the saddle-riding type electric vehicle emphasizes the intake sound in the second stroke among the intake sounds generated during the four cycles from the first stroke to the fourth stroke.

[0020] This allows the power of the motor that drives the drive wheels to produce intake and exhaust sounds similar to those of a reciprocating engine, while reducing the power loss caused by compressing the air in the cylinder.

[0021] From another viewpoint, the saddle-type electric vehicle of the present invention preferably includes the following configuration: the crankshaft adjusts the opening of the intake valve to a third opening degree smaller than the first opening degree during the first stroke, the third stroke, and the fourth stroke, and adjusts the opening of the exhaust valve to a fourth opening degree larger than the third opening degree during the first stroke.

[0022] As described above, the saddle-riding type electric vehicle adjusts the opening of the exhaust valve during the first stroke so that the fourth opening is greater than the third opening of the intake valve. At this time, the amount of air exhausted per unit time from the exhaust port is greater than the amount of air exhausted per unit time from the intake port. Therefore, during the first stroke of the piston, the saddle-riding type electric vehicle generates exhaust noise caused mainly by the air being exhausted from the cylinder through the exhaust port. In this way, in the saddle-riding type electric vehicle, the openings of the intake valve and the exhaust valve are set so that the exhaust sound is emphasized during the first stroke, which corresponds to the exhaust stroke of a reciprocating engine.

[0023] This allows the power of the motor that drives the drive wheels to produce intake and exhaust sounds similar to those of a reciprocating engine, while reducing the power loss caused by compressing the air in the cylinder.

[0024] From another viewpoint, the saddle-riding type electric vehicle of the present invention preferably includes the following configuration: The saddle-riding type electric vehicle has an intake pipe connected to the intake port, an exhaust pipe connected to the exhaust port, and a resonator connected to at least one of the intake pipe and the exhaust pipe.

[0025] As described above, the saddle-type electric vehicle causes the piston to reciprocate using the power of the motor, thereby passing air through the intake pipe, the exhaust pipe, and the resonator. Pressure fluctuations in the air caused by the reciprocating movement of the piston in the cylinder generate compression waves with high and low pressure areas in the intake pipe, the exhaust pipe, and the resonator. The resonator amplifies the sound generated by the compression waves.

[0026] This allows the power of the motor that drives the drive wheels to produce intake and exhaust sounds similar to those of a reciprocating engine, while reducing the power loss caused by compressing the air in the cylinder.

[0027] According to another aspect, the saddle-riding type electric vehicle of the present invention preferably includes the following configuration. The saddle-riding type electric vehicle includes a clutch switchable between a connected state in which power transmitted from the motor to the crankshaft is transmitted to the drive wheels and a disconnected state in which the power is not transmitted to the drive wheels, a control device for controlling the motor, a start switch that outputs a start signal to the control device, and an operator that outputs a drive signal to the control device according to an operation amount. When a start signal is input from the start switch while the clutch is in the disconnected state, the control device supplies a first current from the power source to the motor, causing the motor to output power to rotate the crankshaft at a constant rotation speed. When a drive signal is input from the operator while the control device is supplying the first current to the motor, the control device supplies a second current from the power source to the motor, causing the motor to rotate at a rotation speed based on the drive signal.

[0028] As described above, when the start switch is operated with the clutch disengaged, the saddle-riding electric vehicle rotates the crankshaft at a constant speed using the motor. The saddle-riding electric vehicle reproduces intake noise, exhaust noise, and vibration by moving the piston. In this way, the saddle-riding electric vehicle generates intake noise, exhaust noise, and vibration of a reciprocating engine idling by a start operation similar to that of a saddle-riding vehicle having a four-stroke reciprocating engine.

[0029] Furthermore, in the saddle-riding type electric vehicle, when an operator is operated after the start switch is operated, the crankshaft rotates at a rotation speed based on the amount of operation of the operator. In this way, when the operator is operated, the saddle-riding type electric vehicle generates intake noise, exhaust noise, and vibrations that accompany accelerator operation of a saddle-riding type vehicle having a four-stroke reciprocating engine.

[0030] This allows the power of the motor that drives the drive wheels to produce intake noise, exhaust noise, and vibration similar to that of a reciprocating engine, while reducing the power loss caused by compressing the air in the cylinder.

[0031] According to another aspect, the saddle-type electric vehicle of the present invention preferably includes the following configuration: the start switch is configured as a kick pedal that rotates the crankshaft, and the start switch outputs the start signal to the control device when the kick pedal is depressed.

[0032] As described above, in the saddle-riding type electric vehicle, the crankshaft is rotated by depression of the kick pedal. Furthermore, in the saddle-riding type electric vehicle, a first current is supplied to the motor by depression of the kick pedal. When the motor outputs a torque greater than the dynamic friction resistance of the crankshaft during rotation and less than the static friction resistance of the crankshaft due to the supply of the first current, depression of the kick pedal rotates the crankshaft, thereby rotating the crankshaft at a constant rotation speed.

[0033] Therefore, even if the driver of the saddle-riding type electric vehicle depresses the kick pedal inconsistently, the driver can rotate the crankshaft at a constant rotation speed. In this way, the saddle-riding type electric vehicle generates intake and exhaust sounds equivalent to the start-up operation of a saddle-riding type vehicle having a four-stroke reciprocating engine and the idling state of the reciprocating engine.

[0034] This makes it possible to reduce the intake and exhaust noise and vibrations that are generated in a reciprocating engine, and also to reduce the loss of power that occurs when the air in the cylinder is compressed.

[0035] The terminology used in this specification is used for the purpose of defining particular embodiments only, and is not intended to limit the invention.

[0036] As used herein, "and / or" includes all combinations of one or more of the associated listed members.

[0037] In this specification, the use of "including," "comprising," or "having" and variations thereof identify the presence of stated features, steps, operations, elements, components, and / or equivalents thereof, but may include one or more of the steps, operations, elements, components, and / or groups thereof.

[0038] As used herein, the terms "attached," "connected," "coupled," and / or their equivalents are used broadly to encompass both "direct and indirect" attachments, connections, and couplings. Furthermore, "connected" and "coupled" are not limited to physical or mechanical connections or couplings, but can also include direct or indirect electrical connections or couplings.

[0039] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

[0040] Terms defined in commonly used dictionaries should be construed to have a meaning consistent with the meaning in the context of the relevant art and this disclosure, and should not be construed in an idealized or overly formal sense unless expressly defined herein.

[0041] It will be understood that in describing the present invention, several techniques and processes are disclosed, each of which has distinct advantages and can be used in conjunction with one or more, or in some cases all, of the other disclosed techniques.

[0042] Thus, for the sake of clarity, the description of the present invention refrains from unnecessarily repeating every possible combination of the individual steps, but the specification and claims should be read with the understanding that all such combinations are within the scope of the present invention.

[0043] In this specification, an embodiment of a straddle-type electric vehicle according to the present invention will be described.

[0044] In the following description, numerous specific examples are set forth to provide a thorough understanding of the present invention. However, it will be apparent to one skilled in the art that the present invention may be practiced without these specific examples.

[0045] Accordingly, the following disclosure is to be considered as illustrative of the present invention and is not intended to limit the invention to the specific embodiments illustrated by the following drawings or description.

[0046] [Saddle-ride type vehicle] In this specification, a saddle-ride type vehicle is a vehicle in which a rider sits on a seat straddling the seat. Therefore, the saddle-ride type vehicle is not limited to two-wheeled vehicles, but also includes vehicles such as three-wheeled and four-wheeled vehicles, as long as the rider sits on the seat straddling the seat. The saddle-ride type vehicle may be a vehicle for one person or a vehicle that can accommodate multiple people. The saddle-ride type vehicle also includes a scooter in which the rider sits on the seat without straddling the seat.

[0047] [Saddle-riding type electric vehicle] In this specification, a saddle-riding type electric vehicle refers to a saddle-riding type vehicle in which drive wheels are driven by the power of an electric motor such as a motor. The saddle-riding type electric vehicle does not include vehicles in which drive wheels are driven by the power of an internal combustion engine such as a reciprocating engine. The saddle-riding type electric vehicle includes a saddle-riding type electric vehicle equipped with an engine for generating electricity.

[0048] [Engine] In this specification, the term "engine" refers to an engine that does not generate power. The engine is an engine that does not burn fuel in its cylinders. The engine has, for example, a cylinder head, cylinders, pistons, a crankshaft, intake valves, exhaust valves, etc. The engine is configured such that, when the crankshaft is rotated, the pistons are reciprocated within the cylinders and the openings of the intake valves and exhaust valves are changed.

[0049] [Intake Valve] In this specification, the intake valve refers to a valve that opens most widely when a piston reciprocating within a cylinder moves away from a cylinder head. When the piston moves away from the cylinder head, the most air is taken into the cylinder through an intake hole opened and closed by the intake valve. When the piston moves toward the cylinder head, air may be exhausted to the outside of the cylinder through the intake hole.

[0050] [Exhaust Valve] In this specification, an exhaust valve refers to a valve that opens most widely when a piston reciprocating axially within a cylinder moves toward a cylinder head. When the piston moves toward the cylinder head, the largest amount of air is exhausted to the outside of the cylinder through an exhaust hole opened and closed by the exhaust valve. When the piston moves away from the cylinder head, air may be drawn into the cylinder through the exhaust hole.

[0051] [Opening Degree] In this specification, the opening degree refers to the lift amount of the intake valve relative to the intake port and the lift amount of the exhaust valve relative to the exhaust port. The lift amount is the distance between the intake port seating surface and the intake valve seating surface in the direction of movement of the intake valve, and the distance between the exhaust port seating surface and the exhaust valve seating surface in the direction of movement of the exhaust valve.

[0052] [First Position] In this specification, the first position refers to the position at which the piston, which reciprocates axially within the cylinder, is closest to the cylinder head. The first position corresponds to the top dead center in a reciprocating engine.

[0053] [Second Position] In this specification, the second position refers to the position at which the piston, which reciprocates axially within the cylinder, is furthest from the cylinder head. The second position corresponds to the bottom dead center in a reciprocating engine.

[0054] According to one embodiment of the present invention, it is possible to provide a saddle-type electric vehicle that can reduce the power loss caused by compressing the air in the cylinder while generating intake noise, exhaust noise, and vibrations similar to those of a reciprocating engine using the power of a motor that drives the drive wheels.

[0055] FIG. 1 is a side view showing a saddle-riding type electric vehicle according to a first embodiment of the present invention. FIG. 2 is a front view showing the saddle-riding type electric vehicle according to the first embodiment of the present invention. FIG. 3 is a cross-sectional view showing the internal configuration of a cylinder in an engine of the saddle-riding type electric vehicle according to the first embodiment of the present invention. FIG. 4 is a cross-sectional view of a connection portion between a crankshaft and a motor as viewed from the arrows IV-IV in FIG. 3. FIG. 5 is a partial cross-sectional view showing the opening degrees of the intake valve and the exhaust valve in the first stroke, the second stroke, the third stroke, and the fourth stroke of the engine of the saddle-riding type electric vehicle according to a first modification of the first embodiment of the present invention. FIG. 6 is a partial cross-sectional view showing the opening degrees of the intake valve and the exhaust valve in the first stroke, the second stroke, the third stroke, and the fourth stroke of the engine of the saddle-riding type electric vehicle according to a first modification of the first embodiment of the present invention. FIG. 7 is a cross-sectional view of an engine and a resonator of a saddle-riding type electric vehicle according to a second modification of the first embodiment of the present invention. FIG. 8 is a rear view of the engine and the transmission of the saddle-riding type electric vehicle according to a second embodiment of the present invention. FIG. 9 is a control block diagram of the saddle-riding type electric vehicle according to the second embodiment of the present invention. FIG. 10 is a partial cross-sectional view showing the saddle-riding type electric vehicle according to the first embodiment of the present invention and the opening degrees of the intake valve and the exhaust valve in the first stroke, the second stroke, the third stroke, and the fourth stroke of the engine of the saddle-riding type electric vehicle.

[0056] Each embodiment will be described below with reference to the drawings. In each drawing, the same parts are designated by the same reference numerals, and the description of the same parts will not be repeated. Note that the dimensions of the components in each drawing do not faithfully represent the actual dimensions of the components and the dimensional ratios of the components.

[0057] [Embodiment 1] <Overall configuration of saddle riding type electric vehicle> A saddle riding type electric vehicle 1 according to embodiment 1 of the present invention will be described using Figures 1 to 4. Figure 1 is a side view showing the saddle riding type electric vehicle 1 according to embodiment 1 of the present invention. Figure 2 is a front view showing the saddle riding type electric vehicle 1. Figure 3 is a cross-sectional view showing the internal configuration of a cylinder 11 in an engine 10 of the saddle riding type electric vehicle 1. Figure 4 is a cross-sectional view of the connection portion between a crankshaft 16 and a motor 19 as viewed along arrows IV-IV in Figure 3. The saddle riding type electric vehicle 1 is, for example, a motorcycle.

[0058] 1 , the saddle-riding electric vehicle 1 turns in a leaning position. That is, the saddle-riding electric vehicle 1 leans left when turning left, and leans right when turning right. The saddle-riding electric vehicle 1 includes a frame 2, a steering shaft 3, a seat 4, a front wheel 5, a rear wheel 7, a transmission 9, an engine 10, a motor 19, an intake pipe 20, an exhaust pipe 21, and a battery 22.

[0059] The frame 2 supports each component. The front end of the frame 2 rotatably supports a steering shaft 3. The center of the frame 2 supports a transmission 9, an engine 10, a motor 19, and an intake pipe 20. The rear of the frame 2 supports a swing arm 6 and an exhaust pipe 21. The upper part of the frame 2 supports a seat 4.

[0060] The steering shaft 3 supports the front wheel 5 so as to be steerable. A handlebar 3a is connected to the upper end of the steering shaft 3. A front fork 3b is connected to the lower end of the steering shaft 3. The front wheel 5 is rotatably supported by the front fork 3b.

[0061] The swing arm 6 supports a rear wheel 7, which is a drive wheel. The swing arm 6 is rotatably supported with respect to the frame 2. The rear wheel 7 is rotatably supported by the swing arm 6.

[0062] The transmission 9 changes the rotation speed of the crankshaft 16 and transmits the rotation to the rear wheel 7. The transmission 9 is fixed to the frame 2. As shown in FIG. 3 , the transmission 9 has an input shaft 9a, an output shaft 9b, and a plurality of gears 9c fixed to the input shaft 9a and the output shaft 9b. The input shaft 9a is connected to the crankshaft 16 of the engine 10. The output shaft 9b is connected to the rear wheel 7 via the chain 8 (see FIG. 1 ). Thus, the transmission 9 changes the rotation speed of the crankshaft 16 rotated by the motor 19 and transmits the rotation to the rear wheel 7 via the chain 8.

[0063] The engine 10 generates intake noise, exhaust noise, and vibration. The engine 10 includes a reciprocating engine provided in the saddle-riding type electric vehicle 1. The engine 10 does not output power as a power source. Furthermore, the engine 10 does not combust fuel. That is, in the saddle-riding type electric vehicle 1, the engine 10 functions not as a power source but as a device that generates noise and vibration. The engine 10 is supported by the frame 2 (see FIG. 1 ). The engine 10 is located adjacent to and in front of the transmission 9.

[0064] The engine 10 has a cylinder 11 , a cylinder head 12 , a crankcase 13 , a piston 14 , a connecting rod 15 , a crankshaft 16 , an intake valve 17 , and an exhaust valve 18 .

[0065] The cylinder 11 and the cylinder head 12 form a cylindrical space that compresses air. The cylinder head 12 is fixed to one axial end of the cylinder 11. As a result, one axial opening of the cylinder 11 is closed by the cylinder head 12. The cylinder head 12 has an intake hole 12a and an exhaust hole 12b that communicate with the inside of the cylinder 11. A crankcase 13 is fixed to the other axial end of the cylinder 11. The crankcase 13 houses the transmission 9 and a crankshaft 16.

[0066] The piston 14 draws air into the cylinder 11 and exhausts the air from the cylinder 11. The piston 14 is located within the cylinder 11. The piston 14 is cylindrical and can move axially within the cylinder 11. The piston 14 does not have a piston ring in order to reduce sliding resistance with the cylinder 11. One end of a connecting rod 15 is connected to the piston 14 so as to be rotatable about an axis perpendicular to the direction of movement of the piston 14.

[0067] The crankshaft 16 rotates about its axis to reciprocate the piston 14 in the axial direction of the cylinder 11. The crankshaft 16 also adjusts the opening of the intake valve 17 and the exhaust valve 18. The crankshaft 16 also transmits power from the motor to the transmission 9. The crankshaft 16 is located at the other axial end of the cylinder 11. The crankshaft 16 is supported by the crankcase 13 so as to be rotatable about its axis. One end of the crankshaft 16 extends from inside the crankcase 13 to outside the crankcase 13. In other words, the one end of the crankshaft 16 is located outside the crankcase 13 (see FIG. 4 ). The crankshaft 16 is connected to the input shaft 9a of the transmission 9 within the crankcase 13.

[0068] The other end of the connecting rod 15 is connected to the crankshaft 16 so as to be rotatable about the axis of the crankshaft 16. The rotation of the crankshaft 16 about its axis causes the piston 14 to reciprocate in the axial direction of the cylinder 11. The crankshaft 16 moves the piston 14, within its range of movement, between a first position P1 closest to the cylinder head 12 and a second position P2 farthest from the cylinder head 12.

[0069] The crankshaft 16 is linked to opening and closing mechanisms (not shown) of the intake valve 17 and the exhaust valve 18. The crankshaft 16 rotates about its axis to adjust the opening degrees of the intake valve 17 and the exhaust valve 18 to desired opening degrees.

[0070] The intake valve 17 adjusts the amount of air passing through the intake port 12a. The intake valve 17 is located in the cylinder head 12. The intake valve 17 adjusts the opening of the intake port 12a from inside the cylinder 11. The intake valve 17 is configured to be movable between an open position farthest from the intake port 12a and an open position closest to the intake port 12a within a predetermined movable range in conjunction with the crankshaft 16. The intake valve 17 can be moved to a position that blocks the intake port 12a. The intake valve 17 is configured to be adjustable between the closed position and the open position using an adjustment mechanism (not shown). The effective cross-sectional area of ​​the intake port 12a can be set arbitrarily in the closed position and the open position of the intake valve 17. The intake valve 17 reduces the effective cross-sectional area of ​​the intake port 12a as it approaches the intake port 12a. Therefore, the intake valve 17 adjusts the amount of air passing through the intake port 12a by moving between the open position and the closed position.

[0071] The exhaust valve 18 adjusts the amount of air passing through the exhaust port 12b. The exhaust valve 18 is located in the cylinder head 12. The exhaust valve 18 adjusts the opening of the exhaust port 12b from inside the cylinder 11. The exhaust valve 18 is configured to be movable, in conjunction with the crankshaft 16, between an open position farthest from the exhaust port 12b and a closed position closest to the exhaust port 12b within a predetermined movable range. The exhaust valve 18 can be moved to a position that blocks the exhaust port 12b. The exhaust valve 18 is configured to be adjustable between the closed position and the open position using an adjustment mechanism (not shown). The exhaust valve 18 can arbitrarily set the effective cross-sectional area of ​​the exhaust port 12b at the closed position and the open position. The exhaust valve 18 reduces the effective cross-sectional area of ​​the exhaust port 12b as it approaches the exhaust port 12b. Therefore, the exhaust valve 18 adjusts the amount of air passing through the exhaust port 12b by moving between the open position and the closed position.

[0072] As shown in Figures 1, 2, and 4, the motor 19 outputs power to drive the rear wheel 7. The motor 19 also outputs power to operate the piston 14 of the engine 10. The motor 19 is fixed to the crankcase 13 via a motor flange 19a. An output shaft 19b of the motor 19 is connected to one end of the crankshaft 16 with its axis aligned with the axis of the crankshaft 16. Thus, the motor 19 is configured to rotate the crankshaft 16. The power of the motor 19 is transmitted to the transmission 9 and the piston 14 via the crankshaft 16.

[0073] As shown in Figures 1 and 3, the intake pipe 20 introduces air from outside the cylinder 11 into the cylinder 11. The intake pipe 20 is connected to the intake port 12a. The intake pipe 20 is located behind the cylinder 11 and below the seat 4. The open end of the intake pipe 20 is located near the driver. Air that is mainly drawn into the cylinder 11 from outside the cylinder 11 flows through the intake pipe 20. Air that is exhausted from inside the cylinder 11 to outside the cylinder 11 also flows through the intake pipe 20.

[0074] The exhaust pipe 21 guides air inside the cylinder 11 to the outside of the cylinder 11. The intake pipe 20 is connected to the exhaust hole 12b. The exhaust pipe 21 extends from the front of the cylinder 11, passing below the engine 10, and toward the rear of the frame 2. The opening of the exhaust pipe 21 is located at the rear end of the rear wheel 7. The exhaust pipe 21 mainly carries air that is exhausted from inside the cylinder 11 to the outside of the cylinder 11. The exhaust pipe 21 also carries air that is taken into the cylinder 11 from the outside of the cylinder 11.

[0075] As shown in Fig. 1, the battery 22 supplies power to the electric components and the motor 19 of the saddle-riding type electric vehicle 1. The battery 22 is, for example, a lithium-ion battery. The battery 22 is disposed, for example, in front of the seat 4. The battery 22 is configured to be removable and replaceable. The battery 22 is electrically connected to the motor 19 and each of the electric components of the saddle-riding type electric vehicle 1.

[0076] The saddle-riding type electric vehicle 1 configured in this manner is configured to rotate the crankshaft 16 by the motor 19 without burning fuel in the engine 10. By rotating the crankshaft 16 by the motor 19, the saddle-riding type electric vehicle 1 transmits the rotation of the crankshaft 16 to the rear wheel 7 via the transmission 9 and the chain 8 while causing the piston 14 to move back and forth.

[0077] <Operation of Engine 10> Next, operation of the engine 10 when the crankshaft 16 is rotated by the motor 19 will be described using Figures 1, 3, 5, and 10. Figure 5 is a partial cross-sectional view showing the opening degrees of the intake valve 17 and the exhaust valve 18 in the first stroke S1, the second stroke S2, the third stroke S3, and the fourth stroke S4 of the engine 10 of the saddle riding type electric vehicle 1. Figure 10 is a partial cross-sectional view showing the opening degrees of the intake valve 17 and the exhaust valve 18 in the first stroke S1, the second stroke S2, the third stroke S3, and the fourth stroke S4 of the saddle riding type electric vehicle 1 and the engine 10 of the saddle riding type electric vehicle 1.

[0078] 5 and 10, the first stroke S1 is the stroke in which the piston 14, which is located at the second position P2, moves to the first position P1 due to the rotation of the crankshaft 16 (see FIG. 3). The second stroke S2 ​​is the stroke in which the piston 14, which has moved to the first position P1 in the first stroke S1, moves to the second position P2 due to the rotation of the crankshaft 16. The third stroke S3 is the stroke in which the piston 14, which has moved to the second position P2 in the second stroke S2, moves to the first position P1 due to the rotation of the crankshaft 16. The fourth stroke S4 is the stroke in which the piston 14, which has moved to the first position P1 in the third stroke S3, moves to the second position P2 due to the rotation of the crankshaft 16.

[0079] The first stroke S1 corresponds to the exhaust stroke in a reciprocating engine. The second stroke S2 ​​corresponds to the intake stroke in a reciprocating engine. The third stroke S3 corresponds to the compression stroke in a reciprocating engine. The fourth stroke S4 corresponds to the combustion stroke in a reciprocating engine.

[0080] The intake valve 17 is adjusted to an opening degree that allows air to pass through the intake port 12a in the second stroke S2, and the exhaust valve 18 is adjusted to an opening degree that allows air to pass through the exhaust port 12b in the first stroke S1, the second stroke S2, the third stroke S3, and the fourth stroke S4.

[0081] In the second stroke S2, the intake valve 17 is adjusted to a first opening V1, for example, at which air passes through the intake port 12a. The first opening V1 is, for example, greater than half the full opening of the intake valve 17. In the second stroke S2, the exhaust valve 18 is adjusted to a second opening V2, for example, smaller than the first opening V1 and at which air passes through the exhaust port 12b. The second opening V2 is, for example, smaller than half the full opening of the exhaust valve 18. In the first stroke S1, the third stroke S3, and the fourth stroke S4, the exhaust valve 18 is adjusted to any opening at which air passes through the exhaust port 12b. Note that it is sufficient that the intake valve 17 and the exhaust valve 18 are adjusted to openings at which air passes through the intake port 12a and the exhaust port 12b in the second stroke S2.

[0082] 1 and 3 , the motor 19 rotates the crankshaft 16 to transmit power to the transmission 9. The power transmitted to the transmission 9 is then transmitted to the rear wheel 7 via the chain 8. The crankshaft 16 rotated by the motor 19 adjusts the opening of the intake valve 17 and the exhaust valve 18, and causes the piston 14 to reciprocate within the cylinder 11.

[0083] As shown in Figures 5 and 10, in the first stroke S1, the crankshaft 16 adjusts the opening of the intake valve 17 so that air does not pass through the intake port 12a, and adjusts the opening of the exhaust valve 18 so that air passes through the exhaust port 12b. At the same time, the crankshaft 16 moves the piston 14 toward the cylinder head 12. The engine 10 exhausts air from the cylinder 11 through the exhaust port 12b into the exhaust pipe 21. The exhausted air passes through the exhaust pipe 21 and is discharged to the outside. At this time, compression waves generated in the exhaust pipe 21 cause exhaust noise.

[0084] In the second stroke S2, the crankshaft 16 adjusts the opening of the intake valve 17 to a first opening V1 where air passes through the intake port 12a, and adjusts the opening of the exhaust valve 18 to a second opening V2 where air passes through the exhaust port 12b. In addition, the crankshaft 16 moves the piston 14 toward the crankcase 13. The engine 10 draws external air into the cylinder 11 through the intake pipe 20. Similarly, the engine 10 draws external air into the cylinder 11 through the exhaust pipe 21.

[0085] Intake noise is generated in the intake pipe 20 and the exhaust pipe 21 by compression waves of the air generated by the intake. In this case, the amount of air passing through the intake hole 12a per unit time is greater than the amount of air passing through the exhaust hole 12b per unit time. Therefore, the intake noise generated in the intake pipe 20 is louder than the intake noise generated in the exhaust pipe 21.

[0086] In the third stroke S3, the crankshaft 16 adjusts the opening of the intake valve 17 so that air does not pass through the intake port 12a, and adjusts the opening of the exhaust valve 18 so that air passes through the exhaust port 12b. At the same time, the crankshaft 16 moves the piston 14 toward the cylinder head 12. The engine 10 exhausts air from the cylinder 11 through the exhaust port 12b into the exhaust pipe 21. The exhausted air passes through the exhaust pipe 21 and is discharged to the outside. At this time, exhaust noise is generated by compression waves of the air generated in the exhaust pipe 21.

[0087] In the fourth stroke S4, the crankshaft 16 adjusts the opening of the intake valve 17 so that air does not pass through the intake port 12a, and adjusts the opening of the exhaust valve 18 so that air passes through the exhaust port 12b. At the same time, the crankshaft 16 moves the piston 14 toward the crankcase 13. The engine 10 draws external air into the cylinder 11 through the exhaust pipe 21. At this time, air pressure waves generated in the exhaust pipe 21 cause intake noise.

[0088] In this way, the saddle-riding type electric vehicle 1 adjusts the opening of the intake valve 17 to the first opening V1, which is larger than the second opening V2 of the exhaust valve 18, during the second stroke S2, which corresponds to the intake stroke of a reciprocating engine. In the saddle-riding type electric vehicle 1, air is drawn into the cylinder 11 mainly through the intake port 12a during the second stroke S2. Therefore, during the second stroke S2, intake noise is generated mainly in the intake pipe 20. In this way, in the saddle-riding type electric vehicle 1, the openings of the intake valve 17 and the exhaust valve 18 are set so that the intake noise is emphasized during the second stroke S2. Furthermore, in the saddle-riding type electric vehicle 1, air in the cylinder 11 is exhausted to the outside through at least the exhaust port 12b during the first stroke S1, which corresponds to the exhaust stroke of a reciprocating engine, and the third stroke S3, which corresponds to the compression stroke. Therefore, exhaust noise is generated in the exhaust pipe 21 during the first stroke S1.

[0089] Furthermore, the saddle-riding type electric vehicle 1 generates vibrations due to the reciprocating motion of the piston 14 and the rotational motion of the crankshaft 16 from the first stroke S1 to the fourth stroke S4. At this time, the saddle-riding type electric vehicle 1 adjusts the opening of the exhaust valve 18 so that air passes through the exhaust hole 12b, thereby releasing the air inside the cylinder 11 to the outside in the first stroke S1 and the third stroke S3. This allows the power of the motor 19 that drives the rear wheel 7 to generate intake noise, exhaust noise, and vibrations like a reciprocating engine, and reduces the loss of power caused by compressing the air inside the cylinder 11.

[0090] [First Modification of First Embodiment] Next, a modification of the operation of the engine 10 in the saddle riding type electric vehicle 1 will be described with reference to Fig. 6. Note that in the following embodiment, specific descriptions of the same points as in the embodiments already described will be omitted, and the description will focus on the differences.

[0091] The intake valve 17 is adjusted to a first opening degree V1 in the second stroke S2. In addition, the intake valve 17 is adjusted to a third opening degree V3, which is smaller than the first opening degree V1 and allows air to pass through the intake port 12a, in the first stroke S1, the third stroke S3, and the fourth stroke S4. The third opening degree V3 is, for example, smaller than half the full opening degree of the intake valve 17.

[0092] The exhaust valve 18 is adjusted to an opening degree that allows air to pass through the exhaust port 12b in the first stroke S1, the second stroke S2, the third stroke S3, and the fourth stroke S4. In the first stroke S1, the exhaust valve 18 is adjusted to a fourth opening degree V4 that is larger than the third opening degree V3 of the intake valve 17 and allows air to pass through the exhaust port 12b. The fourth opening degree V4 is, for example, larger than half the full opening degree of the exhaust valve 18. In the second stroke S2, the exhaust valve 18 is adjusted to a second opening degree V2 that is smaller than the first opening degree V1 of the intake valve 17.

[0093] In the first stroke S1, the crankshaft 16 adjusts the opening of the intake valve 17 to opening V3 and the opening of the exhaust valve 18 to a fourth opening V4. At the same time, the crankshaft 16 moves the piston 14 toward the cylinder head 12. The engine 10 exhausts air from the cylinder 11 through the intake port 12a to the intake pipe 20. Similarly, the engine 10 exhausts air from the cylinder 11 through the exhaust port 12b to the exhaust pipe 21. The exhausted air passes through the intake pipe 20 and the exhaust pipe 21 and is discharged to the outside.

[0094] Exhaust noise is generated in the intake pipe 20 and the exhaust pipe 21 by compression waves of the air generated by the exhaust. At this time, the amount of air passing through the exhaust hole 12b per unit time is greater than the amount of air passing through the intake hole 12a per unit time. Therefore, the exhaust noise generated in the exhaust pipe 21 is louder than the exhaust noise generated in the intake pipe 20.

[0095] In the third stroke S3, the crankshaft 16 adjusts the opening of the intake valve 17 to a third opening V3 and adjusts the opening of the exhaust valve 18 to an opening that allows air to pass through the exhaust port 12b. At the same time, the crankshaft 16 moves the piston 14 toward the cylinder head 12. The engine 10 exhausts air from the cylinder 11 through the intake port 12a into the intake pipe 20. Similarly, the engine 10 exhausts air from the cylinder 11 through the exhaust port 12b into the exhaust pipe 21. The exhausted air passes through the intake pipe 20 and the exhaust pipe 21 and is discharged to the outside. At this time, exhaust noise is generated by compression waves generated in the intake pipe 20 and the exhaust pipe 21.

[0096] In the fourth stroke S4, the crankshaft 16 adjusts the opening of the intake valve 17 to the third opening V3 and adjusts the opening of the exhaust valve 18 to an opening that allows air to pass through the exhaust port 12b. At the same time, the crankshaft 16 moves the piston 14 toward the crankcase 13. The engine 10 draws external air into the cylinder 11 through the intake pipe 20. Similarly, the engine 10 draws external air into the cylinder 11 through the exhaust pipe 21. At this time, air compression waves generated in the intake pipe 20 and the exhaust pipe 21 cause intake noise.

[0097] In this way, in the first stroke S1, the saddle-riding type electric vehicle 1 adjusts the opening degree of the exhaust valve 18 to a fourth opening degree V4 that is larger than the third opening degree V3 of the intake valve 17. In the first stroke S1, the saddle-riding type electric vehicle 1 mainly exhausts air from the cylinder 11 through the exhaust hole 12b. Therefore, in the first stroke S1, exhaust noise is mainly generated in the exhaust pipe 21. In this way, in the saddle-riding type electric vehicle 1, the opening degrees of the intake valve 17 and the exhaust valve 18 are set so that the exhaust noise is emphasized in the first stroke S1. This makes it possible to generate intake noise and exhaust noise like those of a reciprocating engine using the power of the motor 19 that drives the rear wheel 7, and to reduce power loss caused by compressing the air in the cylinder 11.

[0098] [Second Modification of First Embodiment] Next, a straddle-type electric vehicle 1A, which is a second modification of the straddle-type electric vehicle, will be described using Figure 7. Figure 7 is a cross-sectional view of the engine 10, intake pipe resonator 23, and exhaust pipe resonator 24 of a straddle-type electric vehicle 1A according to a second modification of the first embodiment of the present invention. The straddle-type electric vehicle 1A has the intake pipe resonator 23 for amplifying sound generated in the intake pipe 20, and the exhaust pipe resonator 24 for amplifying sound generated in the exhaust pipe 21.

[0099] The intake pipe resonator 23 is a hollow housing. The intake pipe resonator 23 is connected to the intake pipe 20. The intake pipe resonator 23 is in communication with the intake pipe 20. Thus, the intake pipe resonator 23 is configured to receive air that has passed through the intake pipe 20. Furthermore, the intake pipe 20 is configured to receive air that has passed through the intake pipe resonator 23. The intake pipe resonator 23 is located, for example, below the seat 4. In other words, the intake pipe resonator 23 is located near the driver. The intake pipe resonator 23 resonates due to the vibration of compression waves of the air that has flowed into it. As a result, the intake pipe resonator 23 amplifies the exhaust sound and the intake sound.

[0100] The exhaust pipe resonator 24 is a hollow housing. The exhaust pipe resonator 24 is connected to the exhaust pipe 21. The exhaust pipe resonator 24 is in communication with the exhaust pipe 21. Thus, the exhaust pipe resonator 24 is configured so that air that has passed through the exhaust pipe 21 flows into it. Furthermore, the exhaust pipe 21 is configured so that air that has passed through the exhaust pipe resonator 24 flows into it. The exhaust pipe resonator 24 is located, for example, behind the seat 4. The exhaust pipe resonator 24 resonates due to the vibration of compression waves of the air that has flowed into it. As a result, the exhaust pipe resonator 24 amplifies the exhaust sound and the intake sound.

[0101] In the saddle-type electric vehicle 1A configured as described above, compression waves are passed through the intake pipe 20, the exhaust pipe 21, the intake pipe resonator 23, and the exhaust pipe resonator 24 by reciprocating the piston 14 with the power of the motor 19 (see FIG. 1). The intake pipe 20, the exhaust pipe 21, the intake pipe resonator 23, and the exhaust pipe resonator 24 amplify the intake noise and exhaust noise generated by the compression waves. As a result, the power of the motor 19 that drives the rear wheel 7 generates intake noise and exhaust noise similar to that of a reciprocating engine.

[0102] [Embodiment 2] <Overall configuration of saddle riding type electric vehicle> A saddle riding type electric vehicle 1B according to embodiment 2 of the present invention will be described using Figures 8 and 9. Figure 8 is a rear view of the engine 10 and transmission 9 of the saddle riding type electric vehicle 1B according to embodiment 2 of the present invention. Figure 9 is a control block diagram of the saddle riding type electric vehicle 1B.

[0103] As shown in FIGS. 8 and 9, the saddle-type electric vehicle 1B further includes a clutch 25 (see FIG. 8), a clutch sensor 26, a start switch 27, an accelerator 28, and a control device 29 (see FIG. 9).

[0104] As shown in FIG. 8 , the clutch 25 transmits the power transmitted to the crankshaft 16 to the transmission 9. The clutch 25 is provided on the crankshaft 16 inside the crankcase 13. The clutch 25 is configured to be switchable between an engaged state in which the power is transmitted to the transmission 9 and a disengaged state in which the power is not transmitted to the transmission 9. The clutch 25 can be switched between the engaged state and the disengaged state by operating an operating device such as a clutch lever (not shown). An input portion of the clutch 25 is fixed to the crankshaft 16. An output portion of the clutch 25 is connected to the input shaft 9a of the transmission 9 via a gear 9c. In the engaged state, the clutch 25 transmits the power of the crankshaft 16 to the transmission 9. In the disengaged state, the clutch 25 does not transmit the power of the crankshaft 16 to the transmission 9.

[0105] 9 , the clutch sensor 26 is a sensor that detects the disengaged state of the clutch 25. The clutch sensor 26 is, for example, a magnetic proximity sensor. When the clutch 25 is switched to the disengaged state by operating the operating tool, the clutch sensor 26 outputs a clutch signal C to the control device 29.

[0106] The start switch 27 outputs a start signal S that causes the motor 19 to rotate at a constant rotation speed. The start switch 27 is provided, for example, on the bar handle 3 a. The start switch 27 is, for example, a push button. When the start switch 27 is pressed, it transmits the start signal S to the control device 29.

[0107] The accelerator 28, which is an operator, is operated to rotate the motor 19 at a desired rotation speed. The accelerator 28 is provided, for example, on the bar handle 3 a. The accelerator 28 is, for example, a rotating grip that can be rotated around the axis of the bar handle 3 a. When the accelerator 28 is rotated, it transmits a drive signal M to the control device 29 based on the amount of rotation.

[0108] The control device 29 controls the motor 19. The control device 29 is electrically connected to the motor 19, the battery 22, the clutch sensor 26, the start switch 27, and the accelerator 28. The control device 29 stores various programs and data for controlling the motor 19, the clutch sensor 26, the start switch 27, and the accelerator 28.

[0109] The control device 29 controls the amount of current supplied from the battery 22 to the motor 19 so that the motor 19 rotates at a desired rotation speed. When the control device 29 receives a clutch signal C from the clutch sensor 26 and a start signal S from the start switch 27, the control device 29 supplies a predetermined first current A1 from the battery 22 to the motor 19. At this time, the motor 19 rotates at a predetermined constant rotation speed. Furthermore, when the control device 29 is supplying the first current A1 from the battery 22 to the motor 19, the control device 29 continues to supply the first current A1 to the motor 19 even if the transmission of the start signal S from the start switch 27 to the control device 29 is stopped.

[0110] When the control device 29 receives a drive signal M from the accelerator 28 while the battery 22 is supplying the first current A1 to the motor 19, the control device 29 supplies a second current A2 from the battery 22 to the motor 19, causing the motor 19 to rotate at a rotation speed based on the drive signal M. At this time, the motor 19 rotates at a rotation speed based on the drive signal M. Furthermore, when the transmission of the drive signal M from the accelerator 28 to the control device 29 is stopped, the control device 29 continues to supply the first current A1 to the motor 19.

[0111] In the saddle-riding type electric vehicle 1B configured as described above, with the clutch 25 switched to the disengaged state, pressing the start switch 27 causes the motor 19 to rotate at a constant rotation speed. That is, when the saddle-riding type electric vehicle 1B is stopped, the operation of the engine 10 by the motor 19 generates intake noise, exhaust noise, and vibration. In this way, the saddle-riding type electric vehicle 1B reproduces the intake noise, exhaust noise, and vibration of a saddle-riding type vehicle having a four-stroke reciprocating engine during starting and idling.

[0112] Furthermore, in the saddle riding type electric vehicle 1B, by operating the accelerator 28, the motor 19 is rotated at a rotation speed based on the amount of operation of the accelerator 28. When the saddle riding type electric vehicle 1B is in a stopped state with the clutch 25 switched to a disengaged state, the operation of the engine 10 by the motor 19 generates intake noise, exhaust noise, and vibration based on the operation of the accelerator 28. When the saddle riding type electric vehicle 1B is in a traveling state with the clutch 25 switched to an engaged state, the operation of the engine 10 by the motor 19 generates intake noise, exhaust noise, and vibration based on the operation of the accelerator 28, while the saddle riding type electric vehicle 1B travels by driving the rear wheel 7 by the motor 19.

[0113] In this way, by controlling the motor 19 based on the operation of the clutch 25, the start switch 27, and the accelerator 28, the saddle-ride type electric vehicle 1B can generate intake noise, exhaust noise, and vibrations in the starting operation of a saddle-ride type vehicle having a four-stroke reciprocating engine, in an idling state, and in response to the operation of the accelerator 28 while driving.

[0114] The start switch 27 may be configured as, for example, a kick pedal that rotates the crankshaft 16. A known mechanism is used to rotate the crankshaft 16 using the kick pedal. When the start switch 27 is depressed, it rotates the crankshaft 16 and transmits a start signal S to the control device 29.

[0115] When the start switch 27 is configured as a kick pedal, the first current A1 supplied to the motor 19 is set to output a torque greater than the dynamic friction resistance of the crankshaft 16 during rotation and smaller than the static friction resistance of the crankshaft 16. Therefore, when the crankshaft 16 is stopped, the motor 19 cannot rotate the crankshaft 16 by supplying the first current A1. On the other hand, when the crankshaft 16 is rotating due to operation of the kick pedal, the motor 19 can rotate the crankshaft 16 by supplying the first current A1.

[0116] In the saddle-riding type electric vehicle 1B, with the clutch 25 switched to the disengaged state and the crankshaft 16 rotated by depression of the start switch 27, a first current A1 is supplied to the motor 19. The motor 19 rotates the crankshaft 16 at a constant rotation speed. In the saddle-riding type electric vehicle 1B, when stopped, the engine 10 generates intake noise, exhaust noise, and vibration.

[0117] The saddle-riding type electric vehicle 1B configured in this manner transmits power from the motor 19 to the crankshaft 16, which is rotated by depressing the kick pedal. Therefore, the driver can easily rotate the crankshaft 16 at a constant speed without failing to start due to variations in the position of the piston or the way the kick pedal is depressed, as occurs with saddle-riding type vehicles having reciprocating engines. In this way, the saddle-riding type electric vehicle 1B reproduces the starting and idling states caused by depressing the pedal of a saddle-riding type vehicle having a four-stroke reciprocating engine.

[0118] Although the embodiments of the present invention have been described above, the above-described embodiments are merely examples for carrying out the present invention. Therefore, the present invention is not limited to the above-described embodiments, and it is possible to appropriately modify the above-described embodiments and carry them out without departing from the spirit of the present invention.

[0119] In the above-described embodiments, the saddle-riding type electric vehicles 1, 1A, and 1B generate intake noise and exhaust noise by adjusting the opening degrees of the intake valve 17 and the exhaust valve 18. However, the saddle-riding type electric vehicles may be configured to maximize the opening degrees of the intake valve and the exhaust valve to suppress the generation of intake noise and exhaust noise. By suppressing the generation of intake noise and exhaust noise, the saddle-riding type electric vehicles can increase the proportion of motor power that can be used to drive the drive wheels. The saddle-riding type electric vehicles are configured to be switchable between, for example, a sound generation mode in which the opening degrees of the intake valve and the exhaust valve are adjusted to different arbitrary opening degrees in each stroke, and a driving priority mode in which the opening degrees of the intake valve and the exhaust valve are adjusted to the maximum opening degrees in each stroke.

[0120] In the above-described embodiments, the saddle-type electric vehicles 1, 1A, 1B generate intake noise, exhaust noise, and vibrations by operating the engine 10, which is provided as a power source, with the motor 19. However, the saddle-type electric vehicles may be configured to separately include a sound and vibration generating device that generates intake noise, exhaust noise, and vibrations, such as a reciprocating engine.

[0121] In the above-described embodiments, the saddle-ride type electric vehicles 1, 1A, and 1B have the crankshaft 16 and the motor 19 fixed to the crankcase 13 connected together. However, the saddle-ride type electric vehicles may be configured so that the power of the motor can be transmitted to the crankshaft and the drive wheels. The motor may be disposed in front of, behind, above, or below the engine.

[0122] In the above-described embodiments, the saddle-riding type electric vehicles 1, 1A, and 1B exhaust air from the cylinder 11 to the outside by adjusting the opening of at least one of the intake valve 17 and the exhaust valve 18 so that air passes through the intake hole 12a and the exhaust hole 12b. However, the saddle-riding type electric vehicles may be configured so that air passes through the mounting hole of the spark plug when the spark plug is removed.

[0123] In the above-described first embodiment, the saddle-riding type electric vehicle 1 adjusts the opening degree of the intake valve 17 to an opening degree that prevents air from passing through the intake port 12a in the first stroke S1, the third stroke S3, and the fourth stroke S4. However, the saddle-riding type electric vehicle may adjust the opening degree of the intake valve to any opening degree that allows air to pass through the intake port in the first stroke S1, the third stroke S3, and the fourth stroke S4.

[0124] In the above-described embodiment, the saddle riding type electric vehicles 1, 1A, 1B adjust the opening degree of the intake valve 17 to the first opening degree V1 that is greater than half of the full open degree, and adjust the opening degree of the exhaust valve 18 to the second opening degree V2 that is less than half of the full open degree, during the second stroke S2. However, the saddle riding type electric vehicles may also adjust the opening degree of the intake valve to the first opening degree that is greater than three-quarters of the full open degree, and adjust the opening degree of the exhaust valve to the second opening degree that is less than one-quarter of the full open degree, during the second stroke S2.

[0125] In the above-described embodiment, the saddle riding type electric vehicles 1, 1A, 1B adjust the opening degree of the intake valve 17 to the third opening degree V3, which is smaller than half of the full opening degree, in the first stroke S1, the third stroke S3, and the fourth stroke S4. However, the saddle riding type electric vehicles may adjust the opening degree of the intake valve to the third opening degree, which is smaller than one-quarter of the full opening degree, in the first stroke S1, the third stroke S3, and the fourth stroke S4.

[0126] In the above-described embodiment, the saddle riding type electric vehicles 1, 1A, 1B adjust the opening degree of the exhaust valve 18 to the fourth opening degree V4, which is greater than half of the full opening degree, during the first stroke S1. However, the saddle riding type electric vehicles may also adjust the opening degree of the exhaust valve to the fourth opening degree, which is greater than three-quarters of the full opening degree, during the first stroke.

[0127] In the above-described embodiments, the saddle riding type electric vehicles 1, 1A, 1B do not specify the opening degree of the exhaust valve 18 in the third and fourth strokes. However, the saddle riding type electric vehicles may adjust the opening degree of the exhaust valve in the third and fourth strokes to an opening degree smaller than half of the full opening degree. Furthermore, the saddle riding type electric vehicles may adjust the opening degree of the exhaust valve in the third and fourth strokes to an opening degree larger than half of the full opening degree.

[0128] In the above-described embodiments, the saddle-riding type electric vehicles 1, 1A, 1B use the motor 19 to drive the rear wheels 7 and the crankshaft 16. However, the saddle-riding type electric vehicles may be configured to have a motor that drives the drive wheels and a motor that drives the crankshaft, respectively.

[0129] In the above-described embodiment, the saddle-type electric vehicle 1B has the clutch 25 that switches between an engaged state and a disengaged state by operating a clutch lever, etc. However, the clutch may be a centrifugal clutch or the like that is not operated by the driver using a clutch lever, etc.

[0130] In the above-described embodiment, the saddle-type electric vehicle 1A has the intake pipe resonator 23 for amplifying the sound generated in the intake pipe 20, and the exhaust pipe resonator 24 for amplifying the sound generated in the exhaust pipe 21. However, the saddle-type electric vehicle may have a configuration including either the intake pipe resonator or the exhaust pipe resonator.

[0131] 1, 1A, 1B saddle-type electric vehicle 2 frame 3 steering shaft 4 seat 5 front wheel 6 swing arm 7 rear wheel 8 chain 9 transmission 10 engine 11 cylinder 12 cylinder head 13 crankcase 14 piston 15 connecting rod 16 crankshaft 17 intake valve 18 exhaust valve 19 motor 20 intake pipe 21 exhaust pipe 22 battery 23 intake pipe resonator 24 exhaust pipe resonator 25 clutch 26 clutch sensor 27 start switch 28 accelerator 29 control device S1 first stroke S2 ​​second stroke S3 third stroke S4 fourth stroke P1 first position P2 second position V1 first opening V2 second opening V3 third opening V4 fourth opening A1 first current A2 Second current S Start signal M Drive signal C Clutch signal

Claims

1. A motor comprising: at least one cylinder; a cylinder head connected to an axial end of the cylinder and having an intake port and an exhaust port communicating with the inside of the cylinder; a piston located within the cylinder and reciprocating in the axial direction of the cylinder; an intake valve whose opening is adjusted to adjust the amount of air passing through the intake port; an exhaust valve whose opening is adjusted to adjust the amount of air passing through the exhaust port; a crankshaft configured to reciprocate the piston between a first position within the cylinder and a second position farther from the cylinder head than the first position by rotation about its axis by the motor, and to transmit power of the motor to drive wheels while adjusting the openings of the intake valve and the exhaust valve; and a power source that supplies power to the motor, A saddle-riding type electric vehicle in which, as the crankshaft rotates, the following processes are repeated in order: a first stroke in which the piston moves from the second position to the first position; a second stroke in which the piston, which moved to the first position in the first stroke, moves to the second position; a third stroke in which the piston, which moved to the second position in the second stroke, moves to the first position; and a fourth stroke in which the piston, which moved to the first position in the third stroke, moves to the second position, wherein the crankshaft: adjusts the opening of an intake valve so that air passes through the intake hole in the second stroke; and adjusts the opening of an exhaust valve so that air passes through the exhaust hole in the first stroke, the second stroke, the third stroke, and the fourth stroke.

2. A saddle-riding type electric vehicle according to claim 1, wherein the crankshaft adjusts the opening of the intake valve to a first opening, and adjusts the opening of the exhaust valve to a second opening that is smaller than the first opening, during the second stroke.

3. A saddle-riding type electric vehicle according to claim 2, wherein the crankshaft adjusts the opening of the intake valve to a third opening degree smaller than the first opening degree during the first stroke, the third stroke, and the fourth stroke, and adjusts the opening of the exhaust valve to a fourth opening degree larger than the third opening degree during the first stroke.

4. A straddle-type electric vehicle according to any one of claims 1 to 3, comprising: an intake pipe connected to the intake port; an exhaust pipe connected to the exhaust port; and a resonator connected to at least one of the intake pipe and the exhaust pipe.

5. A saddle-ride type electric vehicle according to any one of claims 1 to 4, comprising: a clutch switchable between a connected state in which power transmitted from the motor to the crankshaft is transmitted to the drive wheels, and a disconnected state in which the power is not transmitted to the drive wheels; a control device for controlling the motor; a start switch that outputs a start signal to the control device; and an operator that outputs a drive signal to the control device according to an operation amount, wherein the control device, when a start signal is input from the start switch while the clutch is in the disconnected state, supplies to the motor from the power source a first current that causes the motor to output power to rotate the crankshaft at a constant rotation speed, and when a drive signal is input from the operator while the first current is being supplied to the motor, supplies to the motor from the power source a second current that causes the motor to rotate at a rotation speed based on the drive signal.

6. A saddle-ride type electric vehicle according to claim 5, wherein the start switch is configured as a kick pedal that rotates the crankshaft, and outputs the start signal to the control device when the kick pedal is depressed.

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