Patent Description:
In a small-sized straddled vehicle having an idling stop function, an ISG (Integrated Starter Generator) having the function of a starter motor is used, for example. Because having functions of a starter motor and a generator, the ISG is directly attached to a crankshaft without a reduction gear. Therefore, in a case where an ISG is provided in a large-sized straddled vehicle having large displacement, a large torque is required to restart an engine. Therefore, a large-sized ISG is required, and the size of a vehicle further increases.

As such, in a case where an idling stop function is provided in a large-sized straddled vehicle, it is considered that a starter motor not having a power generating function is used. For example, in a straddled vehicle described in Patent Document <NUM>, an electrical connection state between a battery and a starter motor is changed with the use of a starter relay, whereby an engine is started.

Here, the starter relay described in Patent Document <NUM> is a so-called mechanical relay and includes a relay coil and a relay switch. The relay switch is turned ON when the relay coil is excited, and a voltage of a battery is provided to a starter motor. When the relay switch is turned ON, an electric current corresponding to a torque required to start an engine flows through a contact of the switch momentarily.

The contact of the switch deteriorates in accordance with the magnitude of a current flowing in the switch and frequency of change of state of the switch. Therefore, in a case where the state of the relay switch is changed each time the engine that is stopped by the idling stop function is restarted in a large-sized straddled vehicle, the useful life of the relay switch is shortened. Therefore, the relay switch is required to be replaced frequently.

Further, in the above-mentioned starter relay, the state of the switch may be changed due to external vibration or external impact. Therefore, the starter relay is basically attached to a vehicle main body via a buffer member. In this case, flexibility in layout of vehicle component members is restricted in order to ensure an installation space for the starter relay and a buffer member.

An object of the present invention is to provide a straddled vehicle in which frequency of maintenance for replacement of vehicle component members is reduced and flexibility in layout of the vehicle component members is improved.

In the straddled vehicle, the semiconductor relay is used to change between a state in which power is supplied from the battery to the starter motor and a state in which power is not supplied from the battery to the starter motor. In the semiconductor relay, the electrical connection relationship between the battery and the starter motor is changed by an electrical circuit including a semiconductor instead of a stationary contact and a movable contact of a mechanical relay. The semiconductor relay is unlikely to deteriorate in accordance with the magnitude of a current flowing in the semiconductor relay and frequency of change of state as compared to the mechanical relay. Therefore, frequency of replacement of the semiconductor relay is reduced.

Further, due to not having a mechanical movable portion, the semiconductor relay is resistant to external vibration and external impact. Therefore, even in a case where being rigidly fixed to the vehicle main body, the semiconductor relay is unlikely to run erroneously. Therefore, it is not necessary to provide a buffer member in the semiconductor relay. Thus, it is not necessary to ensure a buffer member for the semiconductor relay or an installation space for the buffer member in the straddled vehicle.

As a result, frequency of maintenance for replacement of the vehicle component members is reduced, and flexibility in layout of the vehicle component members is improved.

(<NUM>) The semiconductor relay may be rigidly fixed to the starter motor.

In this case, the semiconductor relay can be handled integrally with the starter motor.

(<NUM>) The semiconductor relay may be rigidly fixed to the engine.

In this case, the semiconductor relay can be handled integrally with the engine.

(<NUM>) The semiconductor relay may be rigidly fixed to the frame.

In this case, the semiconductor relay can be handled integrally with the frame.

(<NUM>) The semiconductor relay is mounted on a circuit board.

In this case, the circuit board is attached to the vehicle main body, so that the semiconductor relay can be rigidly fixed to the vehicle main body.

(<NUM>) The controller may be mounted on the circuit board, and the semiconductor relay may be rigidly fixed to the controller via the circuit board.

In this case, the semiconductor relay can be handled integrally with the controller. Further, the circuit board is attached to the vehicle main body, so that the controller can be rigidly fixed to the vehicle main body in addition to the semiconductor relay.

(<NUM>) The straddled vehicle further includes a change determiner that determines whether the start-up condition is satisfied, and changes a state of the semiconductor relay between a connection state in which the battery and the starter motor are electrically connected to each other and a disconnection state in which the battery and the starter motor are not electrically connected to each other based on a result of determination, wherein the change determiner may be further mounted on the circuit board.

In this case, running of the starter motor can be accurately controlled in accordance with the startup condition. Further, the semiconductor relay and the change determiner can be integrally handled.

(<NUM>) The straddled vehicle may further include a temperature detector that detects a temperature of the semiconductor relay, wherein the controller does not have to stop the engine by the idling stop control in a case where a temperature detected by the temperature detector is higher than a predetermined threshold value.

In this case, in a case where the temperature of the semiconductor relay is higher than the threshold value, the engine is not stopped by the idling stop control. Thus, poor starting performance of the engine due to erroneous running of the semiconductor relay is prevented during restart of the engine caused by the idling stop control.

The present invention enables a reduction in frequency of maintenance for replacement of vehicle component members and improvement of layout of the vehicle component members.

A straddled vehicle according to one embodiment of the present invention will be described below with reference to the drawings. In the following description, a motorcycle is described as one example of the straddled vehicle.

<FIG> is a schematic side view showing the schematic configuration of the motorcycle according to the one embodiment. The motorcycle <NUM> of <FIG> includes a head pipe <NUM> and a body frame <NUM>. The body frame <NUM> includes an upper frame 10a and a lower frame 10b.

The upper frame 10a is formed to extend rearwardly from the head pipe <NUM>. A front half of the lower frame 10b extends obliquely rearwardly and downwardly by a certain distance from the head pipe <NUM> and is curved rearwardly. A rear half of the lower frame 10b extends obliquely rearwardly and upwardly and is connected to the upper frame 10a.

A front fork <NUM> is provided at the head pipe <NUM> to be swingable in a left-and-right direction. A handle <NUM> is attached to the upper end of the front fork <NUM>, and a front wheel <NUM> is rotatably attached to the lower end of the front fork <NUM>.

Handle grips <NUM> are provided at both of the left and right ends of the handle <NUM>. A right handle grip <NUM> also serves as an acceleration grip for adjusting a degree of opening of a throttle valve of an engine <NUM>, described below. A switch unit <NUM> is provided on the handle <NUM> to be adjacent to each handle grip <NUM>. Further, a clutch lever <NUM> that is operable with a rider holding the left handle grip <NUM> is provided at a left portion of the handle <NUM>.

A fuel tank <NUM> and a seat <NUM> are provided on the upper frame 10a to be arranged rearwardly in this order. The engine <NUM> is supported by the body frame <NUM> below the fuel tank <NUM>. The engine <NUM> includes a fuel injection device and a throttle valve for supplying a fuel-air mixture to a combustion chamber, an ignition device for combusting the fuel-air mixture in the combustion chamber, a piston provided to be capable of reciprocating in a cylinder, and a crankshaft. During running (rotation) of the engine <NUM>, a fuel injection amount of the fuel injection device, an opening of the throttle valve (throttle opening) and timing for igniting a fuel-air mixture by the ignition device are controlled. Thus, the piston reciprocates in the cylinder, the reciprocating motion is converted into a rotation motion of the crankshaft and a rotational force of the crankshaft is output.

A starter motor <NUM> for starting the engine <NUM> is provided to be adjacent to the engine <NUM>. An ECU (Engine Control Unit) <NUM> and a battery <NUM> are supported by the body frame <NUM> below the seat <NUM>. Electric power accumulated in the battery <NUM> is supplied to various electric appliances provided in the motorcycle <NUM> as necessary. These electric appliances include a head lamp, a flasher and so on, in addition to the starter motor <NUM> and the ECU <NUM>, described above.

A side stand <NUM> is attached to the lower end of the body frame <NUM> to be capable of supporting the motorcycle <NUM>. The side stand <NUM> is configured to be changeable between a supporting state, in which the side stand <NUM> supports the motorcycle <NUM> on a road surface, and a non-supporting state in which the side stand <NUM> does not support the motorcycle <NUM> on the road surface. In the example of <FIG>, the side stand <NUM> is in the non-supporting state.

A rear arm <NUM> is attached to the engine <NUM> to extend rearwardly from the rear end of the engine <NUM>. A rear wheel <NUM> is rotatably attached to the rear end of the rear arm <NUM>. With the clutch lever <NUM> not operated, a rotational force of the crankshaft that is output from the engine <NUM> is transmitted to the rear wheel <NUM> via a clutch (not shown). Thus, the rotation of the rear wheel <NUM> is driven, and a thrust force of the motorcycle <NUM> is generated.

A transmission mechanism (not shown) is provided in the above-mentioned engine <NUM>. Thus, during travelling of the motorcycle <NUM>, a rotational force transmitted from the crankshaft of the engine <NUM> to the rear wheel <NUM> is adjusted in accordance with a gear position of the transmission mechanism.

The ECU <NUM> includes a CPU (Central Processing Unit) and a memory, or a microcomputer, for example, and is configured to be capable of controlling the engine <NUM> in either an idling stop mode or a non-idling stop mode. A plurality of types of switches and a plurality of types of sensors provided in the motorcycle <NUM> are electrically connected to the ECU <NUM>. The plurality of types of switches includes a mode change switch SW0. The mode change switch SW0 is provided in a right or left switch unit <NUM>, for example, and is operated by the rider in order to change a control mode of the ECU <NUM> between the idling stop mode and the non-idling stop mode.

In a case where the control mode is in the idling stop mode, the ECU <NUM> stops the engine <NUM> when a predetermined idling stop condition is satisfied. Specifically, when the idling stop condition is satisfied, the ECU <NUM> stops at least one of fuel injection by an injector provided in the engine <NUM> and ignition of a fuel-air mixture by the ignition device provided in the engine <NUM>. Thus, the engine <NUM> is stopped. The idling stop condition includes a condition relating to at least one of a throttle opening, a traveling speed of the motorcycle <NUM> and a rotation speed of the crankshaft of the engine <NUM>, for example.

Further, after the engine <NUM> is stopped due to satisfaction of the idling stop condition, the ECU <NUM> starts (restarts) the engine <NUM> when a predetermined idling stop release condition is satisfied. The idling stop release condition is that the right handle grip <NUM> also serving as an acceleration grip is operated, and the throttle opening is larger than <NUM>, for example.

On the other hand, in a case where the control mode is in the non-idling stop mode, the ECU <NUM> does not stop the engine <NUM> even when the idling stop condition is satisfied. In a case where an engine stop switch SW2, described below, is operated by the rider, the ECU <NUM> stops the engine <NUM> regardless of which one of the idling stop mode and the non-idling stop mode the control mode is in.

Whether the idle stop condition is satisfied and whether the idling stop release condition is satisfied are determined based on the states of the plurality of types of switches connected to the ECU <NUM> and the output from the plurality of types of sensors connected to the ECU <NUM>.

<FIG> is a schematic diagram for explaining an electric system for starting the engine <NUM> of <FIG>. As shown in <FIG>, the electric system for starting the engine <NUM> in the motorcycle <NUM> of <FIG> includes a power supply line PL and a change unit <NUM> in addition to the engine <NUM>, the starter motor <NUM>, the ECU <NUM> and the battery <NUM>, described above.

The power supply line PL is provided to connect the starter motor <NUM> and the battery <NUM> to each other. The change unit <NUM> includes a circuit board <NUM>, a semiconductor relay <NUM>, a change determiner <NUM> and a temperature sensor <NUM>, and is provided on the power supply line PL. The semiconductor relay <NUM> and the change determiner <NUM> are mounted on the circuit board <NUM> and electrically connected to each other.

The semiconductor relay <NUM> is configured to be changeable between a connection state in which the starter motor <NUM> and the battery <NUM> are electrically connected to each other via the power supply line PL and a disconnection state in which the starter motor <NUM> and the battery <NUM> are electrically disconnected from each other.

A main switch SW1, an engine stop switch SW2, a clutch switch SW3, a side stand switch SW4, a gear position switch SW5 and a start switch SW6 are electrically connected to the change determiner <NUM>.

The main switch SW1 is provided in a front portion of the vehicle (<FIG>), for example, and is operated by the rider in order to supply power to the electrical appliances provided in each part of the motorcycle <NUM> from the battery <NUM>. In the present example, power can be supplied to each electric appliance of the motorcycle <NUM> from the battery <NUM> when the main switch SW1 is in an ON state. That is, the power supply of the motorcycle <NUM> is turned ON when the main switch SW1 is turned ON. On the other hand, power cannot be supplied to each electric appliance of the motorcycle <NUM> from the battery <NUM> when the main switch SW1 is in an OFF state. That is, the power supply of the motorcycle <NUM> is turned OFF when the main switch SW1 is turned OFF.

The engine stop switch SW2 is provided in the right switch unit <NUM> (<FIG>), for example, and is operated by the rider in order to stop the running (rotating) of the engine <NUM>. In the present example, the engine <NUM> can run when the engine stop switch SW2 is in the ON state. On the other hand, the engine <NUM> cannot run when the engine stop switch SW2 is in the OFF state.

The clutch switch SW3 is provided in the left switch unit <NUM> (<FIG>), for example, and is switched between an ON state and an OFF state in accordance with an operation performed by the rider using the clutch lever <NUM> (<FIG>). In the present example, the state of the clutch switch SW3 in a case where the rider tightly holds the clutch lever <NUM> (the clutch lever <NUM> is operated) is the ON state. On the other hand, the state of the clutch switch SW3 in a case where the rider does not tightly hold the clutch lever <NUM> (the clutch lever <NUM> is not operated) is the OFF state. In this case, the clutch is in a disconnection state when the clutch switch SW3 is in the ON state, and the clutch is in a connection state when the clutch switch SW3 is in the OFF state.

The side stand switch SW4 is provided in the vicinity of the side stand <NUM> (<FIG>). In the present example, the state of the side stand switch SW4 in a case where the side stand <NUM> is in the non-supporting state is an ON state. On the other hand, the state of the side stand switch SW4 in a case where the side stand switch SW4 is in the supporting state is an OFF state.

The gear position switch SW5 is provided at the engine <NUM> (<FIG>). In the present example, the state of the gear position switch SW5 in a case where the gear position of the transmission mechanism is in a neutral position, that is, the state of the gear position switch SW5 in a case where a rotational force transmitted from the crankshaft in the transmission mechanism is not transmitted to the rear wheel <NUM> is an ON state. On the other hand, the state of the gear position switch SW5 in a case where the gear position of the transmission mechanism is in a position other than the neutral position is an OFF state.

The start switch SW6 is provided in the right switch unit <NUM> (<FIG>), for example, and is operated by the rider in order to start the engine <NUM> when in a stop state. In the present example, the start switch SW6 is a button switch that is operable by being depressed by a user. The state of the start switch SW6 being depressed by the rider is an ON state. On the other hand, the state of the start switch SW6 not being depressed by the rider is an OFF state.

Further, in the present embodiment, the start switch SW6 is electrically connected to the ECU <NUM>. Here, the ECU <NUM> supplies a switch ON signal for turning ON the start switch SW6 to the start switch SW <NUM> in a case where the control mode is in the idling stop mode and the above-mentioned idling stop release condition is satisfied. In this case, the start switch SW6 is put in the ON state in response to the switch ON signal in a period during which the switch ON signal is supplied from the ECU <NUM>.

The change determiner <NUM> includes one or a plurality of determination circuits and determines whether a combination of states of the plurality of above-mentioned switches SW1 to SW6 satisfies a predetermined condition for starting the engine <NUM> (hereinafter referred to as a start-up condition).

Further, in a case where the start-up condition is satisfied, the change determiner <NUM> puts the semiconductor relay <NUM> in the connection state. Thus, power of the battery <NUM> is supplied to the starter motor <NUM> through the power supply line PL. On the other hand, in a case where the start-up condition is not satisfied, the change determiner <NUM> puts the semiconductor relay <NUM> in the disconnection state. Thus, power of the battery <NUM> is not supplied to the starter motor <NUM> through the power supply line PL.

With such a configuration, in a case where the engine <NUM> is in the stop state, when the above-mentioned start-up condition is satisfied, power is supplied from the battery <NUM> to the starter motor <NUM>, and the starter motor <NUM> is rotated. Thus, the crankshaft of the engine <NUM> is rotated by a rotational force of the starter motor <NUM>, and the engine <NUM> is started.

<FIG> is a diagram showing one example of start-up conditions. In the present embodiment, the three start-up conditions are respectively defined as a first start-up condition, a second start-up condition and a third start-up condition. In the change determiner <NUM>, determination is made based on the first to third start-up conditions.

As shown in <FIG>, the first start-up condition is that the main switch SW1, the engine stop switch SW2, the clutch switch SW3, the side stand switch SW4 and the start switch SW6 are in the ON state. In a case where the first start-up condition is satisfied, the semiconductor relay <NUM> is put in the connection state regardless of the state of the gear position switch SW5.

The second start-up condition is that the main switch SW1, the engine stop switch SW2, the clutch switch SW3, the gear position switch SW5 and the start switch SW6 are in the ON state. In a case where the second start-up condition is satisfied, the semiconductor relay <NUM> is put in the connection state regardless of the state of the side stand switch SW4.

The third start-up condition is that the main switch SW1, the engine stop switch SW2, the gear position switch SW5 and the start switch SW6 are in the ON state. In a case where the third start-up condition is satisfied, the semiconductor relay <NUM> is put in the connection state regardless of states of the clutch switch SW3 and the side stand switch SW4.

As shown in <FIG>, the temperature sensor <NUM> is provided at the circuit board <NUM> to be in contact with the semiconductor relay <NUM> or to be close to the semiconductor relay <NUM>, and detects a temperature of the semiconductor relay <NUM>. The temperature detected by the temperature sensor <NUM> is supplied to the ECU <NUM>. In a memory of the ECU <NUM>, an upper limit value of the temperature at which the semiconductor relay <NUM> is considered to run normally is stored in advance as a temperature threshold value.

Here, the ECU <NUM> determines whether a temperature detected by the temperature sensor <NUM> is equal to or lower than the temperature threshold value. In a case where the detected temperature is equal to or lower than the temperature threshold value, the ECU <NUM> controls the engine <NUM> in accordance with a control mode set at a current point in time. On the other hand, in a case where the detected temperature is higher than the temperature threshold value, even when the control mode is in the idling stop mode, and the idling stop condition is satisfied, the ECU <NUM> does not execute control to stop the engine <NUM>. Therefore, only in a case where the engine stop switch SW2 is operated or the main switch SW1 is turned OFF, the ECU <NUM> executes control to stop the engine <NUM>.

Thus, it is not necessary to restart the engine <NUM> that is stopped by an idling stop function. Therefore, poor starting performance of the engine <NUM> due to the semiconductor relay <NUM> not running normally is prevented.

The change unit <NUM> is provided integrally with the starter motor <NUM> as shown in <FIG>. More specifically, the semiconductor relay <NUM> that constitutes the change unit <NUM> is rigidly fixed to a bracket or the like included in the starter motor <NUM> with a screw, for example.

The semiconductor relay <NUM> provided in the change unit <NUM> does not have a mechanical movable member, thereby being resistant to external vibration and external impact. Therefore, in a case where the change unit <NUM> is rigidly fixed to the starter motor <NUM>, that is, even in a case where the semiconductor relay <NUM> is rigidly fixed to the starter motor <NUM>, the semiconductor relay <NUM> is unlikely to run erroneously. Therefore, it is not necessary to provide a buffer member in the semiconductor relay <NUM>. Thus, it is not necessary to ensure a buffer member for the semiconductor relay <NUM> or an installation space for the buffer member.

In the motorcycle <NUM>, the change unit <NUM> may be rigidly fixed to a constituent element other than the starter motor <NUM>.

<FIG>are side views showing other examples of the attachment position of the change unit <NUM> in the motorcycle <NUM>. In the example of <FIG>, the change unit <NUM> is rigidly fixed to a crankcase of the engine <NUM>. In this case, the change unit <NUM> can be handled integrally with the engine <NUM>. In the example of <FIG>, the change unit <NUM> is rigidly fixed to the body frame <NUM>. In this case, the change unit <NUM> can be handled integrally with the body frame <NUM>.

In the example of <FIG>, the change unit <NUM> is rigidly fixed to the ECU <NUM>. In this case, the change unit <NUM> can be handled integrally with the ECU <NUM>. Further, in the example of <FIG>, as indicated in the dotted balloon, the CPU <NUM> and the memory <NUM> that constitute the ECU <NUM>, and the semiconductor relay <NUM>, the change determiner <NUM> and the temperature sensor <NUM> of the change unit <NUM> are mounted on a common circuit board <NUM>. That is, the semiconductor relay <NUM> is rigidly fixed to the ECU <NUM> via the circuit board <NUM>. With such a configuration, the change unit <NUM> and the ECU <NUM> can be fabricated at the same time. Thus, the number of manufacturing steps is reduced, and a reduction in cost of the motorcycle <NUM> is realized.

Further, a fuse is provided in the electric system of the motorcycle <NUM>. As such, the semiconductor relay <NUM> may be rigidly fixed to the inside of a fuse box containing the fuse. In this case, the fuse box constitutes part of the vehicle main body.

(g) In the electric system of the motorcycle <NUM>, a circuit for suppressing an inrush current flowing in the starter motor <NUM> during start-up of the engine <NUM> may be provided.

In the following paragraphs, non-limiting examples of correspondences between various elements recited in the claims below and those described above with respect to various preferred embodiments of the present disclosure are explained.

In the above-mentioned embodiment, the head pipe <NUM> and the body frame <NUM> are examples of a frame, the ECU <NUM> is an example of a controller, and the configuration of the motorcycle <NUM> except for the semiconductor relay <NUM> is an example of a vehicle main body. Specifically, a portion that includes the head pipe <NUM>, the body frame <NUM>, the engine <NUM>, the battery <NUM>, the starter motor <NUM> and the ECU <NUM> and excludes the semiconductor relay <NUM> in the motorcycle <NUM> is an example of the vehicle main body. Further, the circuit boards <NUM>, <NUM> are examples of a circuit board, and the temperature sensor <NUM> is an example of a temperature detector.

Claim 1:
A straddled vehicle (<NUM>) comprising:
a vehicle main body that includes a frame (<NUM>), an engine (<NUM>) supported at the frame, a battery (<NUM>), a starter motor (<NUM>) that rotates a crankshaft of the engine by electric power of the battery, and a controller (<NUM>) that executes idling stop control of the engine;
a semiconductor relay (<NUM>) that electrically connects the battery and the starter motor to each other such that electric power is supplied from the battery to the starter motor, in a case where the engine is in a stop state and a predetermined start-up condition is satisfied; and
a change determiner (<NUM>) that determines whether the start-up condition is satisfied, and changes a state of the semiconductor relay between a connection state in which the battery and the starter motor are electrically connected to each other and a disconnection state in which the battery and the starter motor are not electrically connected to each other based on a result of determination,
wherein the semiconductor relay is mounted on a circuit board (<NUM>) rigidly fixed to the vehicle main body.