vehicle

Abstract

To avoid the impartment of an incongruity caused by a change of a usable engine rotational speed region irrespective of an intention of an occupant.SOLUTION: A vehicle 100 comprises a crank pulser 131 for detecting an engine rotational speed NE of an engine 104a, an accelerator grip 15 operated by an occupant, a water temperature sensor 132 for measuring a water temperature TW of cooling water for cooling the engine 104a, and a control unit 50 which can perform excess rotation suppression control for suppressing a rise of the engine rotational speed NW when the rotational speed reaches a control intervention rotational speed which is set according to the water temperature TW. After the water temperature TW exceeds an engine temperature threshold, the control unit 50 can change the control intervention rotational speed on condition that the accelerator grip 15 is operated.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a vehicle. [Background technology]

[0002] Conventionally, some vehicles equipped with an engine (e.g., an engine or a motor) as a drive source limit the rotation speed of the engine in a controlled manner to prevent the engine from becoming overloaded. For example, Patent Document 1 below discloses a technology in which, when an engine rotation speed limiting condition is met, including the engine rotation speed reaching a limit rotation speed corresponding to the temperature of cooling water for cooling the engine, rotation speed limiting control is executed to limit the engine rotation speed. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6413178 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the above-mentioned conventional technology, even if the occupant does not perform any operation to change the engine speed, the limit rotation speed is automatically changed according to the coolant temperature, and the engine speed may change accordingly. Such an unintended change in the engine speed may cause the occupant to feel uncomfortable and may be one of the causes of deterioration in operability of the vehicle.

[0005] In addition, in the above-mentioned conventional technology, the engine speed range that the occupant can use may automatically change before and after the limit speed change, regardless of the occupant's intention (for example, a higher engine speed range may become available). Such a change in the engine speed range that the occupant cannot use may cause the occupant to feel uncomfortable, and may be one of the factors that deteriorate the operability of the vehicle.

[0006] The present invention aims to improve the operability of a vehicle by suppressing the discomfort felt by the occupant due to a change in engine speed at a timing not intended by the occupant or a change in the usable engine speed range unintended by the occupant, thereby further improving traffic safety and contributing to the development of a sustainable transportation system. [Means for solving the problem]

[0007] The present invention relates to a rotation speed detection unit (131) for detecting an engine rotation speed of the engine (104a); Operated by the crew accelerator (15) and an engine temperature measuring unit (132) for measuring an engine temperature, which is the temperature of the engine; The engine rotation speed is set in accordance with the engine temperature. Ta a control unit (50) that executes an overspeed suppression control for suppressing an increase in the engine speed when the engine speed reaches or exceeds a control intervention speed; In a vehicle (100) comprising: The control unit is The engine temperature is an engine temperature threshold If the control intervention rotation speed is equal to or less than the first rotation speed (N1a), When the engine rotation speed reaches the first rotation speed and the engine temperature exceeds the engine temperature threshold, the control intervention rotation speed is maintained at the first rotation speed during a period in which an operation amount of the accelerator is equal to or greater than a predetermined value, and when the operation amount becomes less than the predetermined value, the control intervention rotation speed is maintained at the first rotation speed. The control intervention rotation speed is set to to a second rotation speed (N1b) higher than the first rotation speed Make it modifiable, provide a vehicle. Effect of the Invention

[0008] According to the present invention, it is possible to suppress the discomfort felt by the occupant due to a change in the usable engine rotation speed range unintentionally by the occupant, thereby improving the operability of the vehicle. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a side view of a saddle-type vehicle 100 (vehicle 100) according to one embodiment. [Diagram 2] FIG. 2 is a front view of the vehicle 100. [Diagram 3] FIG. 3 is a block diagram showing an example of a control configuration of the vehicle 100. [Figure 4] FIG. 4 is a flowchart showing an example of a main process executed by the control unit 50. [Diagram 5] FIG. 5 is a flowchart showing an example of each rotation speed setting process. [Figure 6] FIG. 6 is a flowchart showing an example of the state transition process. [Figure 7] FIG. 7 is a flowchart showing an example of the TWREVSTS#0 process. [Figure 8] FIG. 8 is a flowchart showing an example of the TWREVSTS#1 process. [Figure 9] FIG. 9 is a flowchart showing an example of the TWREVSTS#2 process. [Figure 10] FIG. 10 is a flowchart showing an example of the TWREVSTS#3 process. [Figure 11] FIG. 11 is a time chart showing an example of a specific behavior of the vehicle 100. In FIG. [Figure 12] FIG. 12 is a diagram showing a display example of the display device 17. As shown in FIG. [Figure 13] FIG. 13 is a diagram showing a first example of a display by the display device 17 when the water temperature TW exceeds the engine temperature threshold value Tth during overspeed suppression control in the low water temperature mode. [Figure 14] FIG. 14 is a diagram showing a second example of a display by the display device 17 when the water temperature TW exceeds the engine temperature threshold value Tth during overspeed suppression control in the low water temperature mode. [Figure 15] FIG. 15 is a diagram showing a third example of a display by the display device 17 when the water temperature TW exceeds the engine temperature threshold value Tth during overspeed suppression control in the low water temperature mode. [Figure 16] FIG. 16 is a diagram showing a fourth example of a display by the display device 17 when the water temperature TW exceeds the engine temperature threshold value Tth during overspeed suppression control in the low water temperature mode. [Figure 17]FIG. 17 is a diagram showing a fifth example of a display by the display device 17 when the water temperature TW exceeds the engine temperature threshold value Tth during overspeed suppression control in the low water temperature mode. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, an embodiment of the vehicle of the present invention will be described in detail with reference to the accompanying drawings. Note that the following embodiment does not limit the invention according to the claims, and not all combinations of features described in the embodiment are essential to the invention. Two or more features among the multiple features described in the embodiment may be arbitrarily combined. Also, the same reference numbers are used for the same or similar configurations, and duplicated descriptions are omitted.

[0011] <Overview of saddle-type vehicles> Fig. 1 is a side view (right side view) of a saddle-ride type vehicle 100 (hereinafter also simply referred to as "vehicle 100") according to one embodiment. Fig. 2 is a front view of the vehicle 100. Figs. 1 and 2 show a side view and a front view of the vehicle 100 in a state in which the vehicle 100 stands upright in a vertical position. The vehicle 100 of this embodiment is exemplified as a motorcycle having a front wheel 101 and a rear wheel 102, but the present invention is also applicable to other types of saddle-ride type vehicles.

[0012] 1 and 2, arrows X and Y indicate horizontal directions that are perpendicular to each other, and arrow Z indicates an up-down direction. In the following explanation of Fig. 1 and Fig. 2, the traveling direction of vehicle 100 is defined as the X direction, which is the fore-aft direction used to define front and rear. The width direction of vehicle 100 is defined as the Y direction, which is the left-right direction based on the forward direction of the vehicle, which is used to define left and right.

[0013] The vehicle 100 includes a body frame 103 that forms the skeleton of the vehicle. A power unit 104 that drives a rear wheel 102 is supported on the body frame 103. The power unit 104 includes an engine 104a (e.g., a multi-cylinder four-stroke engine) and a transmission 104b that changes the speed of the output of the engine 104a, and the output of the transmission 104b is transmitted to the rear wheel 102 by a chain transmission mechanism. The engine 104a is an example of an engine that drives the vehicle 100.

[0014] A seat frame 103a supporting a seat 108 on which a rider sits is connected to the rear of the body frame 103. A swing arm 109 is supported to be able to swing freely on the rear of the body frame 103, and the rear wheel 102 is supported to be able to rotate freely on the swing arm 109.

[0015] A head pipe is provided at the front of the body frame 103. The head pipe supports the steering mechanism 10 so that the steering mechanism 10 is rotatable.

[0016] The steering mechanism 10 steers the front wheel 101 and includes a pair of front forks 11 and left and right handlebars 14. The pair of front forks 11 are rotatably supported by a head pipe. The pair of front forks 11 are connected at their upper ends by a top bridge, and are connected below the top bridge by a bottom bridge. A steering stem (not shown) is attached so as to extend between the top bridge and the bottom bridge, and the steering stem is rotatably attached inside the head pipe.

[0017] Separate left and right handlebars 14 for steering the front wheel 101 are provided on the upper portion of the pair of front forks 11, and the handlebars 14 are equipped with grips 14a that are held by the rider. The left and right handlebars 14 are arranged so as to incline downward toward the outside in the vehicle width direction when viewed from the front of the vehicle, and are arranged so that the rider can easily ride in a forward-leaning position.

[0018] The vehicle 100 is equipped with braking devices 112, 113. The braking device 112 is a braking device for the front wheel 101, and includes a brake disc 112a provided on the front wheel 101 and a brake caliper 112b supported by the front fork 11. A brake lever 114a for operating the brake caliper 112b is provided on the right handlebar 14. A clutch lever 114b for operating the clutch of the transmission 104b is provided on the left handlebar 14.

[0019] The braking device 113 is a braking device for the rear wheel 102, and includes a brake disc 113a provided on the rear wheel 102 and a brake caliper 113b supported by the swing arm 109. A brake pedal 115 for operating the brake caliper 113b is provided on the right side of the vehicle 100. Steps 116 on which a passenger places their legs are provided on the left and right sides of the vehicle 100, with the brake pedal 115 disposed near the right step 116 and a shift pedal (not shown) disposed near the left step 116.

[0020] Furthermore, the vehicle 100 includes an accelerator grip 15 and a display device 17. The accelerator grip 15 is an example of an operation unit operated by a passenger. The accelerator grip 15 is provided on the grip 14a in a state in which it can rotate around the axis of the grip 14a in response to a twisting operation by the passenger's hand (specifically, the right hand).

[0021] When viewed from the direction shown in Fig. 1, the operation of the occupant twisting and rotating the accelerator grip 15 counterclockwise is an operation to increase the accelerator opening AP, which is the amount of operation on the accelerator grip 15, and is an operation to instruct the acceleration of the vehicle 100. Hereinafter, the operation to increase the accelerator opening AP (i.e., an operation to instruct the acceleration of the vehicle 100) is also referred to as an "acceleration operation." Furthermore, among the acceleration operations, the operation of twisting the accelerator grip 15 counterclockwise to its limit is also referred to as a "full throttle operation."

[0022] On the other hand, when viewed from the direction shown in Fig. 1, an operation of returning the accelerator grip 15 that has been twisted counterclockwise to a clockwise position reduces the accelerator opening AP, and is an operation that instructs the vehicle 100 to decelerate. Hereinafter, an operation of reducing the accelerator opening AP (i.e., an operation that instructs the vehicle 100 to decelerate) is also referred to as a "deceleration operation." Among the deceleration operations, an operation of returning the accelerator grip 15 to the limit in the clockwise direction is also referred to as a "full closure operation."

[0023] The display device 17 is provided at a position where it can be seen by an occupant seated in the seat 108, and is configured to be capable of displaying images representing a tachometer, a speedometer, etc. The display device 17 can also function as a notification unit that notifies the occupant. The display device 17 is realized by, for example, a liquid crystal display, an OLED (Organic Light Emitting Diode) display, etc.

[0024] <Control configuration> Fig. 3 is a block diagram showing an example of a control configuration of the vehicle 100. Fig. 3 mainly illustrates the configuration required in relation to the present embodiment described below.

[0025] The vehicle 100 includes a control unit 50 configured with an ECU (Electric Control Unit) and the like. The control unit 50 is an example of a control unit, and functions as a computer that performs overall control of the entire vehicle 100. The control unit 50 includes a processing unit 51, a storage unit 52 such as a RAM, a ROM, and an I / F unit 53 (interface unit) that relays transmission and reception of signals between an external device and the processing unit 51. The processing unit 51 is a processor represented by a CPU, and executes a program stored in the storage unit 52. The storage unit 52 stores, in addition to the program executed by the processing unit 51, data used by the processing unit 51 for processing, and the like.

[0026] The vehicle 100 further includes a crank pulser 131, a water temperature sensor 132, and an accelerator opening sensor 133. The crank pulser 131 is a sensor that detects an engine rotation speed NE, which is the rotation speed of the engine 104a (e.g., a crankshaft), and outputs the detected value to the control unit 50. The crank pulser 131 is an example of a rotation speed detection unit, and detects the engine rotation speed NE, which is an example of an engine rotation speed.

[0027] The water temperature sensor 132 is a sensor that measures the water temperature TW, which is the temperature of the cooling water that cools the engine 104a, and outputs the measured value to the control unit 50. The water temperature sensor 132 is an example of an engine temperature measuring unit, and measures the water temperature TW, which is an example of an engine temperature, which is the temperature of the engine.

[0028] The accelerator opening sensor 133 is a sensor that detects the accelerator opening AP, which is the amount of operation of the accelerator grip 15, and outputs the detected value to the control unit .

[0029] The engine 104a, which is an example of an engine that drives the vehicle 100, includes a throttle valve 121 and a fuel injection device 122. The throttle valve 121 is a valve that can adjust the amount of air (hereinafter also referred to as the "intake amount") supplied to the engine 104a. In this embodiment, the throttle valve 121 is an electronically controlled throttle valve, and is configured to be able to adjust the intake amount under the control of the control unit 50. The fuel injection device 122 is a device that injects (i.e. supplies) fuel to the engine 104a under the control of the control unit 50.

[0030] The control unit 50 controls the engine 104a by controlling the throttle valve 121 and the fuel injector 122. For example, the control unit 50 derives a target torque, which is a target value of the torque generated by the engine 104a, based on the engine speed NE detected by the crank pulser 131, the water temperature TW measured by the water temperature sensor 132, the accelerator opening AP detected by the accelerator opening sensor 133, and the like, and controls the engine 104a based on the derived target torque. The control unit 50 can also control the display device 17 to cause the display device 17 to perform a predetermined notification. Details of the control performed by the control unit 50 will be described later.

[0031] The control unit 50 may be configured to include a plurality of ECUs (Electric Control Units), each of which includes a processor, a storage device, and an external I / F. For example, the control unit 50 may be configured to include a drive control ECU that controls the throttle valve 121 and the fuel injector 122, and a display control ECU that controls the display device 17. The number of ECUs and the functions handled by each ECU can be designed as appropriate, and the ECUs can be divided more finely or integrated than in the above example.

[0032] <Characteristic Controls Performed by the Control Unit 50> Next, a description will be given of characteristic control performed by the control unit 50 of this embodiment. When the engine speed NE becomes equal to or higher than a predetermined control intervention speed, the control unit 50 executes overspeed suppression control to suppress an increase in the engine speed NE.

[0033] Here, the over-speed suppression control includes, for example, intake amount suppression control for suppressing the intake amount by the throttle valve 121, and fuel supply stop control for thinning out fuel injection to the engine 104a by the fuel injection device 122. By executing such over-speed suppression control, the control unit 50 can suppress an excessive increase in the engine speed NE and suppress the engine 104a from becoming overloaded. A detailed example of the over-speed suppression control will be described later.

[0034] In this embodiment, the control intervention rotation speed, which is a condition for executing the over-speed suppression control, is set according to the water temperature TW. More specifically, when the water temperature TW is equal to or lower than a predetermined engine temperature threshold Tth, the control intervention rotation speed is set to N1a. On the other hand, when the water temperature TW is higher than the engine temperature threshold Tth, the control intervention rotation speed is set to N1b (where N1b>N1a). By changing the control intervention rotation speed, which is a condition for executing the over-speed suppression control, according to the water temperature TW (i.e., the temperature of the engine 104a), in this manner, it becomes possible to appropriately protect the engine 104a. Note that the engine temperature thresholds Tth, N1a, and N1b are set in advance in the control unit 50 by, for example, the manufacturer of the vehicle 100.

[0035] However, if the control unit 50 automatically changes the control intervention speed when the water temperature TW exceeds the engine temperature threshold Tth, the engine speed NE may change in accordance with the change in the control intervention speed even if the occupant does not perform any operation to change the engine speed NE. Such a change in the engine speed NE that is not intended by the occupant may cause the occupant to feel uncomfortable, and may be one of the causes of deterioration in operability of the vehicle 100.

[0036] Furthermore, if the control unit 50 is configured to automatically change the control intervention rotation speed when the water temperature TW exceeds the engine temperature threshold Tth, the engine rotation speed range that the occupant can use may automatically change (for example, a higher engine rotation speed range may become usable) before and after the change in the control intervention rotation speed without the occupant's intention. Such a change in the usable engine rotation speed range that is not intended by the occupant may lead to a sense of discomfort for the occupant and may be one of the causes of reduced operability in the vehicle 100.

[0037] Therefore, in this embodiment, the control unit 50 makes it possible to change the control intervention rotation speed on the condition that the accelerator grip 15 is operated after the water temperature TW exceeds the engine temperature threshold value Tth. This makes it possible to change the control intervention rotation speed based on the operation of the occupant, and therefore makes it possible to prevent the usable engine rotation speed range from changing unintentionally by the occupant. This makes it possible to prevent the occupant from feeling uncomfortable due to a change in the usable engine rotation speed range unintentionally by the occupant, thereby improving the operability (i.e., drivability) of the vehicle 100.

[0038] In addition, by changing the control intervention rotation speed based on the operation of the occupant, it is possible to suppress, for example, an automatic change in the control intervention rotation speed at a timing not intended by the occupant, which in turn suppresses a change in the engine rotation speed NE. Therefore, it is possible to suppress the occupant from feeling uncomfortable due to a change in the engine rotation speed NE at a timing not intended by the occupant, thereby improving the operability of the vehicle 100.

[0039] <Main processing> A specific example of the processing executed by the control unit 50 will be described below with reference to Fig. 4 to Fig. 10. Fig. 4 is a flowchart showing an example of the main processing executed by the control unit 50. For example, when the ignition power supply of the vehicle 100 is on, the control unit 50 repeatedly executes the main processing shown in Fig. 4 at a predetermined cycle.

[0040] In the main process, first, the control unit 50 executes a sensor value acquisition process (step S1). The sensor value acquisition process is a process for acquiring detection values ​​of each sensor of the vehicle 100, including the crank pulser 131, the water temperature sensor 132, the accelerator opening sensor 133, etc.

[0041] Next, the control unit 50 executes each rotation speed setting process (step S2). Each rotation speed setting process is a process for setting a control intervention rotation speed, which is an execution condition of the over-speed suppression control, as well as a target rotation speed and an upper limit rotation speed used in the over-speed suppression control. An example of each rotation speed setting process will be described later with reference to FIG. 5 etc.

[0042] Next, the control unit 50 executes a differential rotation speed calculation process (step S3). The differential rotation speed calculation process is a process for calculating a differential rotation speed between a target rotation speed (e.g., N2a, N2b described later) set in each rotation speed setting process and the current engine rotation speed NE. The differential rotation speed calculated by the differential rotation speed calculation process is used in the engine control process in step S5 described later.

[0043] Next, the control unit 50 executes a state transition process (step S4). The state transition process is a process for transitioning to individual processes according to the flag value of TWREVSTS, which is a flag representing the state of the vehicle 100. Details of TWREVSTS representing the state of the vehicle 100 and the state transition process will be described later with reference to FIG. 6 and the like.

[0044] Next, the control unit 50 executes an engine control process (step S5). The engine control process is a process that derives a target torque, which is a target value of the torque generated by the engine 104a, by referring to a map (table) not shown, based on the current engine rotation speed NE and accelerator opening AP, and controls the engine 104a based on the derived target torque. The engine control process also includes various processes that realize over-rev suppression control.

[0045] Next, the control unit 50 executes a display control process (step S6) and ends the main process. The display control process is a process for controlling the display contents of the display device 17. For example, in the display control process, the control unit 50 causes the display device 17 to display the display screens shown in Figs. 12 to 17, etc., based on the current engine speed NE, accelerator opening AP, water temperature TW, etc.

[0046] <Rotation speed setting process> 5 is a flowchart showing an example of each rotation speed setting process. In each rotation speed setting process, first, the control unit 50 determines whether the flag value of TWREVSTS is 0 or 1 (step S21). As described above, TWREVSTS is a flag representing the state of the vehicle 100. More specifically, TWREVSTS can take any integer from 0 to 4 as the flag value. The correspondence between each flag value of TWREVSTS and the state of the vehicle 100 is as follows:

[0047] TWREVSTS=0: Engine stalled TWREVSTS=1: Update permission status for each NE TWREVSTS=2: Each NE update is prohibited ·TWREVSTS=3 : Torque calculation state TWREVSTS=4: Normal state

[0048] Here, the engine stall state is a state in which the operation of the engine 104a is stopped. The NE update permission state is a state in which updating (i.e., changing) of each NE such as the control intervention rotation speed is permitted. Here, each NE may include, for example, N1a and N1b as the control intervention rotation speed that is an execution condition of the over-speed suppression control, N2a and N2b (described later) as the target rotation speed used in the over-speed suppression control, and N3a and N3b (described later) as the upper limit rotation speed used in the over-speed suppression control. Also, each NE update prohibition state is a state in which updating of each NE such as the control intervention rotation speed is prohibited. The torque calculation state is a state in which derivation (calculation) of the target torque that is the target value of the torque generated by the engine 104a is being performed. The normal state is a state other than these three states.

[0049] When it is determined that the flag value of TWREVSTS is neither 0 nor 1 (step S21; No), that is, when the flag value of TWREVSTS is any of 2 to 4, the control unit 50 ends each rotation speed setting process as it is. In this case, the rotation speeds such as the control intervention rotation speed are not updated (i.e., changed), and the current setting value is maintained.

[0050] On the other hand, when it is determined that the flag value of TWREVSTS is 0 or 1 (step S21; Yes), the control unit 50 determines whether the water temperature TW is equal to or lower than the engine temperature threshold value Tth (step S22).

[0051] When it is determined that the water temperature TW is equal to or lower than the engine temperature threshold value Tth (step S22; Yes), the control unit 50 sets the vehicle 100 to the low water temperature mode (step S23), and ends each rotation speed setting process.

[0052] Here, the low water temperature mode refers to a state in which the control intervention rotation speed that is a condition for executing the over-rotation suppression control is set to N1a, the target rotation speed used for the over-rotation suppression control is set to N2a, and the upper limit rotation speed used for the over-rotation suppression control is set to N3a. It is assumed that N1a, N2a, and N3a satisfy the relationship N1a < N2a < N3a. The specific values adopted as N1a, N2a, and N3a can be appropriately determined by the manufacturer of the vehicle 100 in consideration of the characteristics of the engine 104a and the like.

[0053] On the other hand, when it is determined that the water temperature TW is not less than the engine temperature threshold value Tth (step S22; No), the control unit 50 sets the vehicle 100 to the normal mode (step S24) and ends each rotation speed setting process.

[0054] Here, the normal mode refers to a state in which the control intervention rotation speed is set to N1b, the target rotation speed used for the over-rotation suppression control is set to N2b, and the upper limit rotation speed used for the over-rotation suppression control is set to N3b. It is assumed that N1b, N2b, and N3b satisfy the relationship N1b < N2b < N3b, and further satisfy the relationships N1b > N1a, N2b > N2a, and N3b > N3a. The specific rotation speeds adopted as N1b, N2b, and N3b can be appropriately determined by the manufacturer of the vehicle 100 in consideration of the characteristics of the engine 104a and the like.

[0055] According to each rotation speed setting process described above, when the water temperature TW is less than or equal to the engine temperature threshold value Tth, it can be set to the low water temperature mode, and when the water temperature TW is higher than the engine temperature threshold value Tth, it can be set to the normal mode. Thereby, it becomes possible to set appropriate values corresponding to the current water temperature TW as the control intervention speed, the target rotation speed, and the upper limit rotation speed.

[0056] <State Transition Processing> FIG. 6 is a flowchart showing an example of the state transition process. In the state transition process, first, the control unit 50 determines whether an engine stall has occurred (step S41). If it is determined that an engine stall has occurred (step S41; Yes), the control unit 50 sets the flag value of TWREVSTS to 0 (step S42) and ends the state transition process.

[0057] On the other hand, if it is determined that an engine stall has not occurred (step S41; No), the control unit 50 determines what value the flag value of TWREVSTS is (step S43).

[0058] If the flag value of TWREVSTS is 0, the control unit 50 executes the TWREVSTS#0 process described later with reference to FIG. 7 (step S44) and ends the state transition process. If the flag value of TWREVSTS is 1, the control unit 50 executes the TWREVSTS#1 process described later with reference to FIG. 8 (step S45) and ends the state transition process.

[0059] If the flag value of TWREVSTS is 2, the control unit 50 executes the TWREVSTS#2 process described later with reference to FIG. 9 (step S46) and ends the state transition process. If the flag value of TWREVSTS is 3, the control unit 50 executes the TWREVSTS#3 process described later with reference to FIG. 10 (step S47) and ends the state transition process. If the flag value of TWREVSTS is 4, the control unit 50 ends the state transition process as it is.

[0060] <TWREVSTS#0 process> FIG. 7 is a flowchart showing an example of the TWREVSTS#0 process. As described above, this TWREVSTS#0 process is a process executed when the flag value of TWREVSTS is 0, that is, in the engine stall state.

[0061] In the TWREVSTS#0 process, first, the control unit 50 determines whether the water temperature TW is higher than the engine temperature threshold Tth (step S441). If it is determined that the water temperature TW is higher than the engine temperature threshold Tth (step S441; Yes), the control unit 50 sets the flag value of TWREVSTS to 4 (i.e., normal state) (step S442), and ends the TWREVSTS#0 process.

[0062] On the other hand, when it is determined that the water temperature TW is equal to or lower than the engine temperature threshold value Tth (step S441; No), the control unit 50 determines whether the accelerator is on or not (step S443). Here, the accelerator is on means that the occupant operates the accelerator grip 15 by a predetermined amount or more (for example, the amount of play of the accelerator grip 15 or more) and an accelerator opening AP larger than 0 is detected. More specifically, in this embodiment, the accelerator opening AP at which the accelerator is switched between on and off is set as the accelerator opening threshold value APth. That is, in this embodiment, the state in which the accelerator opening AP is equal to or higher than the accelerator opening threshold value APth is set as the accelerator on, and the state in which the accelerator opening AP is less than the accelerator opening threshold value APth is set as the accelerator off. Here, the accelerator opening threshold value APth can be set to, for example, 0, but is not limited thereto, and may be a value larger than 0. That is, the accelerator off is not limited to the full closing operation of the accelerator grip 15.

[0063] When it is determined that the accelerator is on (step S443; Yes), the control unit 50 sets the flag value of TWREVSTS to 2 (that is, each NE update is prohibited state) (step S444), and ends the TWREVSTS#0 processing.

[0064] On the other hand, if it is determined that the accelerator is not on (step S443; No), that is, if it is determined that the accelerator is off, the control unit 50 sets the flag value of TWREVSTS to 1 (i.e., each NE update is permitted) (step S445) and terminates TWREVSTS#0 processing.

[0065] <TWREVSTS#1 Process> FIG. 8 is a flowchart showing an example of the TWREVSTS#1 process. As described above, this TWREVSTS#1 process is a process executed when the flag value of TWREVSTS is 1, that is, in each NE update permission state.

[0066] In the TWREVSTS#1 process, first, the control unit 50 determines whether the coolant temperature TW is higher than the engine temperature threshold value Tth (step S451). If it is determined that the coolant temperature TW is higher than the engine temperature threshold value Tth (step S451; Yes), the control unit 50 sets the flag value of TWREVSTS to 4 (i.e., normal state) (step S452), and ends the TWREVSTS#1 process.

[0067] On the other hand, if it is determined that the coolant temperature TW is less than or equal to the engine temperature threshold value Tth (step S451; No), the control unit 50 determines whether the engine rotational speed NE is equal to or higher than the control intervention rotational speed set (step S453). That is, when the low coolant temperature mode is set, the control unit 50 determines in step S453 whether the engine rotational speed NE is equal to or higher than N1a. On the other hand, when the normal mode is set, the control unit 50 determines in step S453 whether the engine rotational speed NE is equal to or higher than N1b.

[0068] If it is determined that the engine rotational speed NE is equal to or higher than the control intervention rotational speed (step S453; Yes), the control unit 50 sets the flag value of TWREVSTS to 3 (i.e., torque calculation state) (step S454), and ends the TWREVSTS#1 process.

[0069] On the other hand, if it is determined that the engine rotational speed NE is less than the control intervention rotational speed (step S453; No), the control unit 50 determines whether the accelerator is on, in the same manner as in step S443 described above (step S455).

[0070] When it is determined that the accelerator is on (step S455; Yes), the control unit 50 sets the flag value of TWREVSTS to 2 (i.e., each NE update prohibited state) (step S456), and ends the TWREVSTS#1 process. On the other hand, when it is determined that the accelerator is not on (i.e., the accelerator is off) (step S455; No), the control unit 50 simply ends the TWREVSTS#1 process.

[0071] <TWREVSTS#2 process> Figure 9 is a flowchart showing an example of the TWREVSTS#2 process. As described above, this TWREVSTS#2 process is a process executed when the flag value of TWREVSTS is 2, i.e., in each NE update prohibited state.

[0072] In the TWREVSTS#2 process, first, the control unit 50 determines whether or not the engine rotation speed NE is equal to or higher than the control intervention rotation speed set, in the same manner as in step S453 described above (step S461).

[0073] When it is determined that the engine rotation speed NE is equal to or higher than the control intervention rotation speed (step S461; Yes), the control unit 50 sets the flag value of TWREVSTS to 3 (i.e., torque calculation state) (step S462), and ends the TWREVSTS#2 process.

[0074] On the other hand, when it is determined that the engine rotation speed NE is less than the control intervention rotation speed (step S461; No), the control unit 50 determines whether or not the accelerator is on, in the same manner as in step S443 described above (step S463).

[0075] When it is determined that the accelerator is on (step S463; Yes), the control unit 50 ends the TWREVSTS#2 process as it is. On the other hand, when it is determined that the accelerator is not on (i.e., the accelerator is off) (step S463; No), the control unit 50 sets the flag value of TWREVSTS to 1 (i.e., each NE update permission state) (step S464) and ends the TWREVSTS#2 process.

[0076] <TWREVSTS#3 process> FIG. 10 is a flowchart showing an example of the TWREVSTS#3 process. As described above, this TWREVSTS#3 process is a process executed when the flag value of TWREVSTS is 3, i.e., in the torque calculation state.

[0077] In the TWREVSTS#3 process, first, the control unit 50 determines whether the engine rotational speed NE is equal to or higher than the control intervention rotational speed being set, in the same manner as step S453 described above (step S471). When it is determined that the engine rotational speed NE is equal to or higher than the control intervention rotational speed (step S471; Yes), the control unit 50 ends the TWREVSTS#3 process as it is.

[0078] On the other hand, when it is determined that the engine rotational speed NE is less than the control intervention rotational speed (step S471; No), the control unit 50 determines whether the accelerator is on, in the same manner as step S443 described above (step S472).

[0079] When it is determined that the accelerator is on (step S472; Yes), the control unit 50 sets the flag value of TWREVSTS to 2 (i.e., each NE update prohibition state) (step S473) and ends the TWREVSTS#3 process.

[0080] On the other hand, if it is determined that the accelerator is not on (i.e., the accelerator is off) (step S472; No), the control unit 50 sets the flag value of TWREVSTS to 1 (i.e., each NE update permitted state) (step S474), and ends the TWREVSTS#3 processing.

[0081] According to the state transition process including each process from the TWREVSTS#0 process to the TWREVSTS#3 process described above, when the engine rotation speed NE is less than the control intervention rotation speed, the flag value of TWREVSTS can be set to 1 (i.e., each NE update permitted state) in response to the accelerator being released (see steps S461, S463, and S464 in FIG. 9, or steps S471, S472, and S474 in FIG. 10). Then, by setting the flag value of TWREVSTS to 1, it becomes possible to change from the low water temperature mode to the normal mode (see steps S22 and S24 in FIG. 5).

[0082] In addition, the condition for setting the TWREVSTS flag value to 1 (i.e., each NE update permitted state) is, for example, a full closure operation when the accelerator is off, but is not limited to this. Even if a deceleration operation other than a full closure operation (for example, an operation of returning the accelerator grip 15 to a certain extent) is performed, the TWREVSTS flag value may be set to 1 and a change from the low water temperature mode to the normal mode may be permitted.

[0083] <An example of a specific behavior of the vehicle 100> Fig. 11 is a time chart showing an example of a specific behavior of the vehicle 100. In Fig. 11(a), the vertical axis represents engine speed NE, and the horizontal axis represents time. In Fig. 11(b), the vertical axis represents water temperature TW, and the horizontal axis represents time. In Fig. 11(c), the vertical axis represents accelerator opening AP, and the horizontal axis represents time. In Fig. 11(d), the vertical axis represents target torque, and the horizontal axis represents time.

[0084] At time t0 shown in Fig. 11, the water temperature TW is equal to or lower than the engine temperature threshold value Tth, so the vehicle 100 is in the low water temperature mode. That is, the control intervention rotation speed is set to N1a, the target rotation speed is set to N2a, and the upper limit rotation speed is set to N3a. The occupant turns on the accelerator at time t0, and starts full throttle operation at time t1 immediately after time t0.

[0085] In this case, the accelerator opening AP gradually increases from the above-mentioned accelerator opening threshold APth (for example, accelerator opening AP = 0) from time t0 to time t1, and reaches a maximum value of 100 from time t1. As a result, the target torque derived based on the accelerator opening AP also gradually increases from time t1, and reaches a value corresponding to the accelerator opening AP of 100 from time t1. As the accelerator opening AP and target torque increase in this way, the engine speed NE also increases from time t0. And as the engine speed NE increases, the water temperature TW also increases from time t0.

[0086] At time t2 after time t1, the engine speed NE reaches N1a, which is set as the control intervention speed. In this case, the control unit 50 starts the overspeed suppression control from time t2, and controls the engine speed NE to converge to N2a, which is set as the target speed. This suppresses the increase in the engine speed NE compared to before the overspeed suppression control started (here, before time t2).

[0087] In this embodiment, when the engine speed NE reaches the control intervention speed (here, N1a), the control unit 50 first executes intake air amount suppression control to suppress the intake air amount (amount of air supplied to the engine 104a) as the over-speed suppression control. For example, during the intake air amount suppression control, the control unit 50 determines the intake air amount by referring to an intake air amount map different from that used during normal times (when the intake air amount suppression control is not being performed), and controls the throttle valve 121 based on the determined intake air amount, thereby reducing the intake air amount compared to normal times. This makes it possible to suppress an increase in the engine speed NE compared to normal times, i.e., before the intake air amount suppression control is performed.

[0088] In the example shown in Fig. 11, the target torque derived based on the accelerator opening AP during over-speed suppression control (in other words, the target torque requested by the occupant) is, for example, as shown by the dashed line in Fig. 11(d). However, if the engine 104a is controlled with the target torque requested by the occupant during over-speed suppression control, it may not be possible to suppress an increase in the engine speed NE. In such a case, as shown by the solid line in Fig. 11(d), the control unit 50 suppresses an increase in the engine speed NE by setting the target torque used in the actual control of the engine 104a lower than the target torque requested by the occupant.

[0089] However, even if the intake amount suppression control is executed, a certain amount of air is supplied to the engine 104a. As a result, even if the intake amount suppression control is executed, the engine 104a can continue combustion (i.e., operation). On the other hand, even if the intake amount suppression control is executed, the increase in the engine rotation speed NE cannot be suppressed, and the engine rotation speed NE may reach the upper limit rotation speed. In the example shown in Fig. 11, at time t3 after time t2 when the intake amount suppression control is started, the engine rotation speed NE exceeds N3a, which is set as the upper limit rotation speed.

[0090] In this embodiment, when the engine speed NE exceeds the upper limit speed (here, N3a) in this way, the control unit 50 executes fuel supply cut control (hereinafter also referred to as "FC control (Fuel Cut)") as the over-speed suppression control. During the FC control, the control unit 50 thins out the fuel injection device 122 from injecting fuel into the engine 104a. This makes it possible to reliably suppress an increase in the engine speed NE. In the example shown in FIG. 11, the engine speed NE starts to decrease from time t4 after time t3 when the FC control is started.

[0091] Then, when the engine speed NE becomes equal to or lower than the upper limit speed (here, N3a) during the FC control, the control unit 50 ends the FC control and again controls the engine speed NE to converge to the target speed (here, N2a) only by the intake air amount suppression control. In the example shown in Fig. 11, since the engine speed NE becomes equal to or lower than N3a at time t5 after time t4, only the intake air amount suppression control is executed as the over-speed suppression control from time t5.

[0092] In the example shown in Fig. 11, the water temperature TW exceeds the engine temperature threshold Tth at time t31 between time t3 and time t4. However, even at time t31, the driver continues to operate the engine at full throttle. In such a case, the control unit 50 does not switch to the normal mode at time t31 even if the water temperature TW exceeds the engine temperature threshold Tth, and maintains the low water temperature mode. That is, even after time t31, the control unit 50 maintains the control intervention rotation speed at N1a, the target rotation speed at N2a, and the upper limit rotation speed at N3a.

[0093] Then, suppose that the driver starts releasing the accelerator grip 15 at time t6 after the water temperature TW exceeds the engine temperature threshold Tth. As a result, the engine speed NE drops below N1a, which is set as the control intervention speed, at time t7' after time t6. In this case, the control unit 50 ends the over-speed suppression control at time t7'.

[0094] Then, at time t7 after time t7', the accelerator is released and the engine speed NE is less than N1a set as the control intervention speed. In this case, at time t7, the control unit 50 switches the vehicle 100 to the normal mode. That is, at time t7, the control unit 50 changes the control intervention speed to N1b, the target speed to N2b, and the upper limit speed to N3b. As a result, as shown in FIG. 11, even if the accelerator is released after time t7 and the engine speed NE reaches N1a again, the control unit 50 can quickly increase the engine speed NE without executing the overspeed suppression control.

[0095] As described above, the control unit 50 changes the control intervention rotation speed when the accelerator grip 15 is released after the water temperature TW exceeds the engine temperature threshold Tth. This makes it possible to change the control intervention rotation speed based on the occupant's operation, making it possible to prevent the usable engine rotation speed range from changing unintentionally. This makes it possible to prevent the occupant from feeling uncomfortable due to a change in the usable engine rotation speed range unintentionally, thereby improving the operability of the vehicle 100. This in turn makes it possible to further improve traffic safety and contribute to the development of a sustainable transportation system.

[0096] In addition, by changing the control intervention rotation speed based on the operation of the occupant, it is possible to suppress, for example, an automatic change in the control intervention rotation speed at a timing not intended by the occupant, which in turn suppresses a change in the engine rotation speed NE. Therefore, it is possible to suppress the occupant from feeling uncomfortable due to a change in the engine rotation speed NE at a timing not intended by the occupant, thereby improving the operability of the vehicle 100.

[0097] Furthermore, the control unit 50 changes the control intervention rotation speed when the accelerator grip 15 is released and the engine speed NE falls below the set control intervention rotation speed after the water temperature TW exceeds the engine temperature threshold Tth. This makes it possible to prevent the control intervention rotation speed from being changed when the engine speed NE is higher than the set control intervention rotation speed. Therefore, it is possible to prevent the control intervention rotation speed from being changed when the engine speed NE is high, and to prevent the occupants from feeling uncomfortable due to a sudden change (more specifically, a sudden increase) in the engine speed NE caused by the change in the control intervention rotation speed.

[0098] Furthermore, since the engine rotation speed NE changes in accordance with the amount of operation of the accelerator grip 15 (i.e., the accelerator opening AP), the occupant can achieve both of the conditions for making the control intervention rotation speed changeable, that is, "operation of the accelerator grip 15" and "keeping the engine rotation speed NE below the currently set control intervention rotation speed," by operating the accelerator grip 15. This enables the occupant to change the control intervention rotation speed with minimal operation, improving the convenience of the vehicle 100.

[0099] In addition, the control unit 50 can change the control intervention rotation speed when there is an operation to make the engine rotation speed NE less than the control intervention rotation speed being set. In other words, even if there is an operation to change the engine rotation speed NE, the control unit 50 can prevent the control intervention rotation speed from being changed unless the operation is an operation to make the engine rotation speed NE less than the control intervention rotation speed being set. This makes it possible to suppress, for example, a change in the control intervention rotation speed in response to an operation to slightly lower the engine rotation speed NE or an operation to increase the engine rotation speed NE. Therefore, it is possible to suppress a change in the usable engine rotation speed range unintentionally by the occupant, or a change in the control intervention rotation speed at a timing not intended by the occupant, and to suppress the occurrence of these occurrences causing discomfort to the occupant.

[0100] However, some occupants may wish to change the control intervention rotation speed as quickly as possible. Therefore, when the water temperature TW exceeds the engine temperature threshold value Tth, the control unit 50 may be configured to notify the occupant via the display device 17 to prompt the occupant to operate the accelerator grip 15. As an example, in the case of the example shown in Fig. 11, the control unit 50 may be configured to notify the occupant to operate the accelerator grip 15 during the period from time t31 to time t7.

[0101] In this way, when the water temperature TW exceeds the engine temperature threshold Tth, a notification is given to prompt the driver to operate the accelerator grip 15, so that the driver can refer to the notification and quickly operate the accelerator grip 15 to change the control intervention rotation speed. This allows the driver to drive the vehicle 100 by using a high rotation speed range as the engine rotation speed NE, for example.

[0102] Furthermore, when the water temperature TW rises and approaches the engine temperature threshold value Tth, the control unit 50 may notify the occupant via the display device 17 that the water temperature TW has approached the engine temperature threshold value Tth. As an example, in the case of the example shown in FIG. 11, the control unit 50 may notify the occupant that the water temperature TW has approached the engine temperature threshold value Tth during the period from time t30 before time t31 to time t31. Here, time t30 may be, for example, the time when the water temperature TW has reached the engine temperature threshold value Tth-ΔT (where ΔT>0). The specific value adopted as ΔT may be appropriately determined by the manufacturer of the vehicle 100.

[0103] In this way, when the water temperature TW rises and approaches the engine temperature threshold Tth, the occupant is notified that the water temperature TW is approaching the engine temperature threshold Tth, and the occupant can use this notification to prepare to operate the accelerator grip 15 (specifically, prepare to release the accelerator grip 15) before the water temperature TW exceeds the engine temperature threshold Tth. This allows the occupant to quickly operate the accelerator grip 15 to change the control intervention rotation speed when the water temperature TW exceeds the engine temperature threshold Tth.

[0104] <Example of display on a display device> Specific examples of display on the display device 17 will be described below with reference to Fig. 12 to Fig. 17. However, the display mode of the display device 17 is not limited to those shown in the drawings.

[0105] Fig. 12 is a diagram showing an example of display on the display device 17. In Fig. 12, (a) is a display in low water temperature mode without overspeed suppression control, (b) is a display in low water temperature mode with overspeed suppression control, (c) is a display in normal mode without overspeed suppression control, and (d) is a display in normal mode with overspeed suppression control.

[0106] Display device 17 is configured to be able to display a tachometer 171, a speedometer 172, and a low water temperature mode icon 173. Tachometer 171 displays, for example, the current engine rotation speed NE using an indicator 175. Indicator 175 expands and contracts in the left-right direction in Fig. 12 according to the current engine rotation speed NE, and more specifically, the higher the engine rotation speed NE, the further it extends in the right direction in Fig. 12.

[0107] The tachometer 171 is also provided with a control intervention rotation speed display 176 and a red zone 177. The control intervention rotation speed display 176 indicates the control intervention rotation speed being set. For example, as shown in Figs. 12(a) and (b), when the control intervention rotation speed display 176 is "10", it indicates that the control intervention rotation speed being set is "10 x 1000 r / min (i.e. 10000 r / min)". On the other hand, as shown in Figs. 12(c) and (d), when the control intervention rotation speed display 176 is "13", it indicates that the control intervention rotation speed being set is "13 x 1000 r / min (i.e. 13000 r / min)".

[0108] The red zone 177 represents a rotation speed region higher than the currently set control intervention rotation speed (i.e., a rotation speed region where overspeed suppression control is executed). For example, in the example shown in Fig. 12(a) and (b), the red zone 177 represents a rotation speed region higher than "10 x 1000 r / min (i.e., 10000 r / min)". On the other hand, in the example shown in Fig. 12(c) and (d), the red zone 177 represents a rotation speed region higher than "13 x 1000 r / min (i.e., 10000 r / min)".

[0109] The speedometer 172 numerically displays the current driving speed (i.e., vehicle speed) of the vehicle 100. The low water temperature mode icon 173 is an icon that is displayed when the vehicle 100 is in the low water temperature mode, and indicates that the vehicle 100 is in the low water temperature mode by displaying, for example, characters such as "Low temp mode." Note that the display color, displayed characters, etc. of the low water temperature mode icon 173 can be changed, as described below.

[0110] Fig. 12(a) is a display in low water temperature mode without overspeed suppression control, and corresponds to the display in the period from time t0 to time t2 shown in Fig. 11, for example. At this time, the occupant is notified by tachometer 171 that the current engine speed NE has not reached the control intervention speed (10 x 1000 r / min). In addition, the occupant is notified by the display of low water temperature mode icon 173 that vehicle 100 is in the low water temperature mode.

[0111] When the engine speed NE increases from the state shown in FIG. 12(a) and the overspeed suppression control is started, the display changes to the low water temperature mode with overspeed suppression control shown in FIG. 12(b). This display corresponds to the display during the period from time t2 to time t7 shown in FIG. 11, for example. At this time, the occupant is notified by the tachometer 171 (more specifically, the indicator 175 entering the red zone 177) that the current engine speed NE is higher than the control intervention speed (here, 10×1000 r / min), that is, that the overspeed suppression control is being executed. Also, as in FIG. 12(a), the occupant is notified by the display of the low water temperature mode icon 173 that the vehicle 100 is in the low water temperature mode.

[0112] If the water temperature TW rises from the state shown in FIG. 12(b) and exceeds the engine temperature threshold value Tth, and the occupant then releases the accelerator grip 15, causing the engine speed NE to fall below the control intervention speed, the display changes to that of FIG. 12(c), indicating normal mode and no over-speed suppression control. This display corresponds to the display from time t7 onward shown in FIG. 11. At this time, the occupant is notified by the tachometer 171 that the current engine speed NE has not reached the control intervention speed (here, 13×1000 r / min). In addition, the low water temperature mode icon 173 is not displayed, thereby notifying the occupant that the vehicle 100 is in normal mode.

[0113] Note that if the driver releases the accelerator grip 15 and the engine speed NE falls below the control intervention speed before the water temperature TW rises from the state shown in Fig. 12(b) and exceeds the engine temperature threshold Tth, the display returns to Fig. 12(a). Also, even if overspeed suppression control is not executed, if the water temperature TW rises from the state shown in Fig. 12(a) and exceeds the engine temperature threshold Tth, the display changes to Fig. 12(c).

[0114] Then, when the engine speed NE increases from the state shown in FIG. 12(c) and the overspeed suppression control is started, the display changes to the normal mode with overspeed suppression control shown in FIG. 12(d). At this time, the occupant is notified by the tachometer 171 (more specifically, the indicator 175 enters the red zone 177) that the current engine speed NE is higher than the control intervention speed (here, 13×1000 r / min), that is, that the overspeed suppression control is being executed. Also, as in FIG. 12(c), the low water temperature mode icon 173 is hidden to notify the occupant that the vehicle 100 is in the normal mode. Then, when the engine speed NE decreases from the state shown in FIG. 12(d) and becomes less than the control intervention speed, the display returns to the display shown in FIG. 12(c).

[0115] Furthermore, when the water temperature TW exceeds the engine temperature threshold Tth, the display device 17 may notify the occupant to operate the accelerator grip 15. Fig. 13 is a diagram showing a first example of a display by the display device 17 when the water temperature TW exceeds the engine temperature threshold Tth during overspeed suppression control in the low water temperature mode. In Fig. 13, (a) shows a display when the water temperature TW≦the engine temperature threshold Tth, and (b) shows a display when the water temperature TW>the engine temperature threshold Tth.

[0116] 13(a), when the water temperature TW is equal to or lower than the engine temperature threshold value Tth in the low water temperature mode, the display device 17 may display the low water temperature mode icon 173 in, for example, a blue display color. On the other hand, when the water temperature TW exceeds the engine temperature threshold value Tth in the low water temperature mode, as shown in FIG 13(b), the display device 17 may display the low water temperature mode icon 173 in, for example, a green display color.

[0117] That is, when the water temperature TW exceeds the engine temperature threshold value Tth in the low water temperature mode, as at time t31 shown in Fig. 11, the display device 17 may change the display color of the low water temperature mode icon 173. This allows the display device 17 to notify the occupant that the water temperature TW has exceeded the engine temperature threshold value Tth, that is, that the control intervention rotation speed can be changed in response to the operation of returning the accelerator grip 15, by using the display color of the low water temperature mode icon 173. This allows the occupant to refer to this notification and quickly operate the accelerator grip 15 to change the control intervention rotation speed.

[0118] In FIG. 13, when the water temperature TW exceeds the engine temperature threshold Tth in the low water temperature mode, the display color of the low water temperature mode icon 173 is changed, but this is not limited to the above.

[0119] Fig. 14 is a diagram showing a second example of the display by the display device 17 when the water temperature TW exceeds the engine temperature threshold Tth during overspeed suppression control in the low water temperature mode. In Fig. 14, (a) shows the display when the water temperature TW≦the engine temperature threshold Tth, and (b) shows the display when the water temperature TW>the engine temperature threshold Tth.

[0120] As shown in Fig. 14(a), when the water temperature TW is equal to or lower than the engine temperature threshold value Tth in the low water temperature mode, the display device 17 may display a low water temperature mode icon 173 with text such as "Low temp mode". On the other hand, as shown in Fig. 14(b), when the water temperature TW exceeds the engine temperature threshold value Tth in the low water temperature mode, the display device 17 may display a low water temperature mode icon 173 with text such as "Low temp mode Turn off the accelerator".

[0121] In this case, the display device 17 can notify the occupant by using text on the low water temperature mode icon 173 that the water temperature TW has exceeded the engine temperature threshold value Tth, i.e., that the control intervention rotation speed can be changed in response to the operation of returning the accelerator grip 15. This enables the occupant to refer to this notification and quickly operate the accelerator grip 15 to change the control intervention rotation speed.

[0122] Fig. 15 is a diagram showing a third example of the display by display device 17 when water temperature TW exceeds engine temperature threshold Tth during overspeed suppression control in low water temperature mode. For example, as shown in Fig. 14(a) and other figures, when water temperature TW is equal to or lower than engine temperature threshold Tth in low water temperature mode, display device 17 may display low water temperature mode icon 173 with text such as "Low temp mode". Then, as shown in Fig. 15, when water temperature TW exceeds engine temperature threshold Tth in low water temperature mode, display device 17 may display low water temperature mode icon 173 in a flashing manner.

[0123] In this case, the display device 17 can notify the occupant that the water temperature TW has exceeded the engine temperature threshold value Tth, i.e., that the control intervention rotation speed can be changed in response to the operation of returning the accelerator grip 15, by flashing the low water temperature mode icon 173. This enables the occupant to refer to this notification and quickly operate the accelerator grip 15 to change the control intervention rotation speed.

[0124] Fig. 16 is a diagram showing a fourth example of the display by the display device 17 when the water temperature TW exceeds the engine temperature threshold value Tth during overspeed suppression control in the low water temperature mode. In Fig. 16, (a) shows the display when the water temperature TW≦the engine temperature threshold value Tth, and (b) shows the display when the water temperature TW>the engine temperature threshold value Tth.

[0125] As shown in Figures 16(a) and (b), the display device 17 may notify the occupant by displaying the tachometer 171 that the water temperature TW has exceeded the engine temperature threshold value Tth, i.e., that the control intervention rotation speed can be changed in response to the operation of releasing the accelerator grip 15.

[0126] For example, assume that in the low water temperature mode, the water temperature TW exceeds the engine temperature threshold Tth, and the control intervention speed can be changed from 10×1000 r / min as N1a to 13×1000 r / min as N1b. In this case, the display device 17 may notify the occupant of the increase in the control intervention speed when the control intervention speed is changed by, for example, changing the display color of the portion of the tachometer 171 that corresponds to the rotation speed range from 10×1000 r / min to 13×1000 r / min from the other portions, as shown in Fig. 16(b).

[0127] Even in this case, the display device 17 can notify the occupant by the display mode of the tachometer 171 that the water temperature TW has exceeded the engine temperature threshold value Tth, i.e., that the control intervention rotation speed can be changed in response to the operation of returning the accelerator grip 15. Therefore, the occupant can refer to this notification and quickly operate the accelerator grip 15 to change the control intervention rotation speed.

[0128] Fig. 17 is a diagram showing a fifth example of the display by the display device 17 when the water temperature TW exceeds the engine temperature threshold Tth during overspeed suppression control in the low water temperature mode. For example, as shown in Fig. 16(a) etc., when the water temperature TW is equal to or lower than the engine temperature threshold Tth in the low water temperature mode, the display device 17 may display the red zone 177 in the tachometer 171 in a non-blinking state. Then, as shown in Fig. 17, when the water temperature TW exceeds the engine temperature threshold Tth in the low water temperature mode, the display device 17 may display the red zone 177 in the tachometer 171 in a blinking state.

[0129] In this case, the display device 17 can notify the occupant that the water temperature TW has exceeded the engine temperature threshold value Tth, i.e., that the control intervention rotation speed can be changed in response to the operation of releasing the accelerator grip 15, by flashing the red zone 177. This enables the occupant to refer to this notification and quickly operate the accelerator grip 15 to change the control intervention rotation speed.

[0130] Furthermore, when the water temperature TW rises during over-speed suppression control and approaches the engine temperature threshold value Tth, the display device 17 may change the display color or text of the low water temperature mode icon 173, cause the low water temperature mode icon 173 to flash, or change the display mode of the tachometer 171.

[0131] In this way, the display device 17 can notify the occupant that the water temperature TW is approaching the engine temperature threshold Tth. Therefore, the occupant can use this notification to prepare to operate the accelerator grip 15 (specifically, prepare to release the accelerator grip 15) before the water temperature TW exceeds the engine temperature threshold Tth. As a result, when the water temperature TW exceeds the engine temperature threshold Tth, the occupant can quickly operate the accelerator grip 15 to change the control intervention rotation speed.

[0132] The above describes the form for carrying out the present invention using an embodiment, but the present invention is not limited to such an embodiment, and various modifications and substitutions can be made within the scope that does not deviate from the gist of the present invention.

[0133] For example, in the above-described embodiment, the engine that drives the vehicle 100 includes the engine 104a, but this is not limited to the above. The engine that drives the vehicle 100 may be configured with a motor. Furthermore, when the engine that drives the vehicle 100 is a motor, the temperature of the motor itself may be used as the engine temperature instead of the water temperature TW described above.

[0134] In the above-described embodiment, the control intervention rotation speed is changed on the condition that the accelerator grip 15 is operated, but this is not limited to the above. For example, the control intervention rotation speed may be changed on the condition that a predetermined operation button for accepting an operation to change the control intervention rotation speed is operated.

[0135] In the above embodiment, the notification unit that notifies the occupant is the display device 17, but is not limited to this. For example, instead of or in addition to the display device 17, a lamp indicator, a speaker, or the like may be used as the notification unit that notifies the occupant.

[0136] This specification describes at least the following items. Note that, in parentheses, components corresponding to those in the above-mentioned embodiment are shown, but the present invention is not limited to these.

[0137] (1) a rotation speed detection unit (crank pulser 131) for detecting an engine rotation speed of an engine (engine 104a); An operating unit (accelerator grip 15) operated by the occupant; an engine temperature measuring unit (water temperature sensor 132) for measuring an engine temperature, which is the temperature of the engine; a control unit (control unit 50) that executes an over-speed suppression control to suppress an increase in the engine speed when the engine speed becomes equal to or higher than a control intervention speed that is set according to the engine temperature; In a vehicle (vehicle 100) equipped with The control unit makes the control intervention rotation speed variable on condition that the operation unit is operated after the engine temperature exceeds an engine temperature threshold.

[0138] According to (1), since the control intervention speed can be changed based on the operation of the occupant, it is possible to prevent the usable engine speed range from changing unintentionally by the occupant. This makes it possible to prevent the occupant from feeling uncomfortable due to the usable engine speed range changing unintentionally by the occupant, thereby improving the operability of the vehicle. This in turn makes it possible to further improve traffic safety and contribute to the development of a sustainable transportation system.

[0139] (2) A vehicle as described in (1), The control unit makes the control intervention rotation speed changeable under the conditions that the operating unit is operated after the engine temperature exceeds the engine temperature threshold and the engine rotation speed becomes less than the control intervention rotation speed.

[0140] According to (2), it is possible to prevent the control intervention speed from being changed when the engine speed is higher than the control intervention speed, and therefore it is possible to prevent the control intervention speed from being changed when the engine speed is high, and to prevent a sudden change (more specifically, a sudden increase) in the engine speed caused by the change in the control intervention speed from causing discomfort to the occupants.

[0141] (3) A vehicle as described in (2), The engine rotation speed changes in accordance with an amount of operation of the operating unit.

[0142] According to (3), the occupant can achieve both of the conditions for making the control intervention rotation speed changeable, namely, "operating the operating unit" and "keeping the engine rotation speed below the control intervention rotation speed," by operating the operating unit. This enables the occupant to change the control intervention rotation speed with minimal effort, improving the convenience of the vehicle.

[0143] According to (3), when an operation is performed to make the engine speed less than the control intervention speed, the control intervention speed can be changed. In other words, even if an operation is performed to change the engine speed, the control intervention speed can be prevented from being changed unless the operation is an operation to make the engine speed less than the control intervention speed. This makes it possible to prevent the control intervention speed from being changed in response to, for example, an operation to slightly decrease the engine speed or an operation to increase the engine speed. Therefore, it is possible to prevent the control intervention speed from being changed at a timing not intended by the occupant, and to avoid the occupant feeling uncomfortable due to the change in the engine speed caused by the change in the control intervention speed.

[0144] (4) A vehicle according to any one of (1) to (3), The vehicle further includes a notification unit (display device 17) that issues a notification to a vehicle occupant to prompt the occupant to operate the operating unit when the engine temperature exceeds the engine temperature threshold value.

[0145] According to (4), when the engine temperature exceeds the engine temperature threshold, a notification is given urging the occupant to operate the operating unit. This enables the occupant to use this notification to quickly operate the operating unit and change the control intervention rotation speed.

[0146] (5) A vehicle as described in (4), When the engine temperature increases and approaches the engine temperature threshold, the notification unit further notifies an occupant that the engine temperature has approached the engine temperature threshold.

[0147] According to (5), when the engine temperature rises and approaches the engine temperature threshold, the occupant is notified that the engine temperature is approaching the engine temperature threshold. This enables the occupant to use this notification as a reference and prepare to operate the operating unit before the engine temperature exceeds the engine temperature threshold. [Explanation of symbols]

[0148] 15 Accelerator grip (operating part) 17 Display device (notification section) 50 Control unit (control section) 100 vehicles 104a Engine 131 Crank pulser (rotation speed detector) 132 Water temperature sensor (engine temperature measurement section)

Claims

1. A rotation speed detection unit (131) for detecting an engine rotation speed of an engine (104a); An accelerator (15) operated by the occupant; an engine temperature measuring unit (132) for measuring an engine temperature, which is the temperature of the engine; a control unit (50) that executes an over-speed suppression control for suppressing an increase in the engine speed when the engine speed becomes equal to or higher than a control intervention speed set in accordance with the engine temperature; In a vehicle (100) comprising: The control unit is When the engine temperature is equal to or lower than an engine temperature threshold value, the control intervention rotation speed is set to a first rotation speed (N1a); a control unit configured to control the engine temperature to a predetermined value when the engine rotation speed reaches the first rotation speed and the engine temperature exceeds the engine temperature threshold value, the control intervention rotation speed is maintained at the first rotation speed during a period when an operation amount of the accelerator is equal to or greater than a predetermined value, and the control intervention rotation speed is changeable to a second rotation speed (N1b) higher than the first rotation speed when the operation amount becomes less than the predetermined value.

2. 2. A vehicle as claimed in claim 1, The control unit is a control unit configured to control the engine speed to a predetermined value in response to the engine temperature threshold value, the control intervention speed being changed to the second rotation speed under the conditions that the manipulated variable is less than the predetermined value and the engine speed is less than the first rotation speed, when the over-speed suppression control is being executed as a result of the engine speed reaching the first rotation speed and the engine temperature exceeds the engine temperature threshold value.

3. 3. A vehicle according to claim 2, The engine rotation speed varies in accordance with the operation amount.

4. A vehicle according to any one of claims 1 to 3, The vehicle further includes a notification unit (17) that issues a notification to a passenger to encourage him or her to release the accelerator when the over-rev suppression control is being executed because the engine rotation speed has reached the first rotation speed and the engine temperature exceeds the engine temperature threshold value.

5. A vehicle according to claim 4, When the engine temperature increases and approaches the engine temperature threshold, the notification unit further notifies an occupant that the engine temperature has approached the engine temperature threshold.

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