Vehicle warning devices

Abstract

This helps to suppress the driver's numbness to the accelerator. [Solution] A vehicle warning device that is installed on a vehicle capable of driving while limiting the vehicle speed to an upper limit, and which issues a warning, changes the degree of the warning according to the excess torque obtained by subtracting the upper limit driving torque when the vehicle is driven at the upper limit speed from the driving request torque based on the accelerator opening. As a result, it is possible to suppress the driver's dulling of accelerator sensitivity.

Description

Technical Field

[0001] The present disclosure relates to a warning device for a vehicle.

Background Art

[0002] Conventionally, as a warning device for this type of vehicle, a device mounted on a vehicle capable of traveling at a vehicle speed below an upper vehicle speed based on a restricted speed has been proposed (see, for example, Patent Document 1). In this device, when the upper vehicle speed decreases as the restricted speed decreases, the driver is notified of this fact.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the above-described warning device, when the vehicle speed has reached the upper vehicle speed, the vehicle speed may not change accordingly even if the driver changes the accelerator opening degree. In this case, the driver's accelerator feeling may become dull.

[0005] The warning device of the present disclosure has a main object of suppressing dulling of the driver's accelerator feeling.

Means for Solving the Problems

[0006] The warning device of the present disclosure has adopted the following means in order to achieve the above-described main object.

[0007] The warning device of the present disclosure is a warning device for a vehicle that is mounted on a vehicle capable of traveling while restricting the vehicle speed to an upper vehicle speed and issues a warning, When the vehicle speed is limited to the upper limit vehicle speed, the degree of the warning is changed according to the excess torque obtained by subtracting the upper limit driving torque when the vehicle is driven at the upper limit vehicle speed from the driving request torque based on the accelerator opening. This is the gist of it.

[0008] In the warning device of this disclosure, when the vehicle speed is limited to the upper speed limit, the degree of the warning changes according to the excess torque obtained by subtracting the upper speed limit driving torque when the vehicle is driven at the upper speed limit from the driving request torque based on the accelerator opening. When the accelerator opening changes, the excess torque changes, and the degree of the warning changes. Therefore, the driver can recognize the change in accelerator opening by the change in the degree of the warning. As a result, the driver's sensitivity to the accelerator can be suppressed. [Brief explanation of the drawing]

[0009] [Figure 1] This is a schematic diagram of an electric vehicle equipped with a warning device according to an embodiment of the disclosure. [Figure 2] This flowchart shows an example of a processing routine executed by the ECU. [Figure 3] This is an explanatory diagram illustrating an example of the relationship between the base volume, the upper volume limit, and the requested volume. [Modes for carrying out the invention]

[0010] Embodiments of this disclosure will be described with reference to the drawings. Figure 1 is a schematic diagram of an electric vehicle equipped with a warning device according to an embodiment of this disclosure. As shown in the figure, the electric vehicle 20 of the embodiment includes a driving motor 32, an inverter 34, a battery 36, and an electronic control unit (hereinafter referred to as "ECU") 50.

[0011] The motor 32 is configured as a three-phase AC motor and comprises a rotor with permanent magnets embedded in the rotor core and a stator with three-phase coils wound around the stator core. The rotor of the motor 32 is connected to a drive shaft 26 which is connected to drive wheels 22a and 22b via a differential gear 24.

[0012] The inverter 34 is used to drive the motor 32 and is connected to the power line 38. When a DC voltage is applied to the inverter 34, the ECU 50 controls the switching of multiple switching elements in the inverter 34, thereby forming a rotating magnetic field in the three-phase coil of the motor 32 and driving the motor 32 to rotate.

[0013] The battery 36 is configured as, for example, a lithium-ion secondary battery, a nickel-metal hydride secondary battery, or a fuel cell with a rated voltage of several hundred volts, and is connected to the power line 38.

[0014] The navigation device 40 comprises a main unit 42 having a storage medium such as a hard disk on which map information is stored, a CPU, ROM, RAM, input / output ports, and communication ports; a GPS antenna 44 that receives information about the vehicle's current location; and a touch panel type display 46 that displays various information such as map information, the vehicle's current location, and the planned route to the destination, and allows the user to input various instructions. Here, the map information includes service information (for example, information about facilities, parking lots, charging equipment, etc.) and road information for predetermined driving sections (for example, between traffic lights or between intersections, etc.). The road information includes distance information, width information, number of lanes information, regional information (urban areas or suburbs), type information (general roads, expressways, toll roads), gradient information, legal speed limits, number of traffic lights, and upper limit speed Vlim. The upper limit speed Vlim is the speed corresponding to the 80th percentile when the speeds of multiple vehicles traveling in the driving section are collected and arranged in ascending order. The upper limit vehicle speed Vlim is set for each driving section and for each time of day, such as early morning, daytime, and nighttime. The navigation device 40 is connected to the ECU 50 via a communication port. When the user operates the display 46 to set a destination in the navigation device 40, the main unit 42 sets a planned driving route from the current location to the destination based on map information, the vehicle's current location, and the destination, and displays the set planned driving route on the display 46 to provide route guidance. The navigation device 40 exchanges various signals with the ECU 50 via communication.

[0015] The ECU50 is equipped with a microcomputer, which includes a CPU, ROM, RAM, flash memory, input / output ports, and communication ports. Signals from various sensors are input to the ECU50 via its input ports. Examples of signals input to the ECU50 include the rotational position θm from a rotational position sensor (e.g., resolver) 32a that detects the rotational position of the rotor of the motor 32, the phase currents Iv and Iw from current sensors that detect the V-phase and W-phase currents of the motor 32, the voltage Vb from a voltage sensor attached between the terminals of the battery 36, the current Ib from a current sensor attached to the output terminal of the battery 36, the start signal from the start switch 60, the shift position SP from a shift sensor 62 that detects the operating position of the shift lever 61, the accelerator opening Acc from an accelerator sensor 64 that detects the amount of depression of the accelerator pedal 63, the brake pedal position from a brake sensor 66 that detects the amount of depression of the brake pedal 65, the vehicle speed V from a vehicle speed sensor 67, and the battery temperature Tb from a temperature sensor that detects the temperature of the battery 36. Various control signals are output from the ECU50 via its output ports. Signals output from the ECU 50 include, for example, control signals to the inverter 34 and speakers 68 installed in the passenger compartment. The ECU 50 calculates the state of charge (SOC) of the battery 36 based on the current Ib of the battery 36 from the current sensor. The state of charge (SOC) is the ratio of the amount of power that can be discharged from the battery 36 to the total capacity of the battery 36.

[0016] In the electric vehicle 20 of this configured embodiment, the ECU 50 sets the required driving torque Td* based on the accelerator opening Acc and the vehicle speed V. Next, it obtains the upper limit vehicle speed Vlim of the currently driven section from the navigation device 40 and sets the upper limit driving torque Tdlim required to drive the vehicle at the upper limit vehicle speed Vlim based on the driving resistance and losses in the differential gear 24 when driving at the upper limit vehicle speed Vlim. The upper limit driving torque Tdlim is set as the corresponding balancing torque when the upper limit vehicle speed Vlim is given, after pre-determining the relationship between the balancing torque that balances the deceleration torque due to the driving resistance and losses in the differential gear 24 when driving at the upper limit vehicle speed Vlim through experiments, analyses, machine learning, etc. The smaller of the set required driving torque Td* and the upper limit driving torque Tdlim is set as the torque command Tm* for the motor 32, and the switching control of multiple transistors in the inverter 34 is performed so that the motor 32 is driven by the torque command Tm*. With this control, the electric vehicle 20 can travel while limiting the vehicle speed V to an upper limit vehicle speed Vlim.

[0017] Next, the operation of the electric vehicle 20 of the embodiment configured in this way, in particular, the operation when a warning sound is emitted from the speaker 68, will be described. Figure 2 is a flowchart showing an example of a processing routine executed by the ECU. This routine is executed when the driving request torque Td* is greater than the upper limit driving torque Tdlim, that is, when the vehicle speed V is limited by the upper limit vehicle speed Vlim.

[0018] When this routine is executed, the CPU of the ECU50 receives the driving request torque Td* and the upper limit driving torque Tdlim as input (S100). Next, it subtracts the upper limit driving torque Tdlim from the driving request torque Td* to calculate the excess torque Texc, which is the torque that the driver is excessively requesting relative to the upper limit driving torque Tdlim (S120). Then, it sets the requested volume Vo* to the smaller of the basic volume Voref and the upper limit volume Vomax, which are based on the excess torque Texc (S130).

[0019] Figure 3 is an explanatory diagram illustrating an example of the relationship between the base volume, upper volume limit, and required volume. In the figure, the solid line represents the required volume Vo*. The dashed line represents the base volume Voef. The base volume Voef is set to be larger when the excess torque Texc is large compared to when it is small. Furthermore, when the excess torque Texc is large, the base volume Voef moves along a straight line L1 with a slope k1 that passes through the point where the excess torque Texc is value 0 and the base volume Voef is value 0, and when the excess torque Texc is small, it moves along a straight line L2 with a slope k2 that passes through the point where the excess torque Texc is value 0 and the base volume Voef is value S1, with a slope k2 less than that of k1. Value S1 is the lower limit of the volume that a human can perceive while the electric vehicle 20 is in operation. When the excess torque Texc is small and then increases while moving along the line L2, the system moves along the line L1 while maintaining a constant required volume Vo*, as shown by the horizontal arrow in the figure when the excess torque Texc is value T1. Also, when the excess torque Texc is large and then decreases while moving along the line L1, the system moves along the line L2 while maintaining a constant required volume Vo*.

[0020] Then, the speaker 68 is controlled so that a warning sound of the required volume Vo* is emitted (S140). Then, it is determined whether the brake pedal 65 is on or whether the required volume Vo* is the value 0 (S150). When the brake pedal 65 is off and the required volume Vo* is not the value 0, S100 to S150 are repeated. When the brake pedal 65 is turned on in S150 or when the required volume Vo* becomes the value 0, if a warning sound is being emitted from the speaker 68, the output of the warning sound is stopped (S160) and this routine ends. In the present embodiment, since the required volume Vo* is set as shown in FIG. 2, when the accelerator opening Acc increases and the required running torque Td* increases and the excess torque Texc increases from the value 0, the volume of the warning sound emitted from the speaker 68 gradually increases from the value 0, and when it reaches the upper limit volume Vomax via the value S1, it becomes constant at the upper limit volume Vomax. Then, when the accelerator opening Acc decreases and the required running torque Td* decreases and the excess torque Texc decreases toward the value 0, the volume of the warning sound emitted from the speaker 68 gradually decreases from the upper limit volume Vomax to the value S1. Thus, since the volume (degree of the warning sound) of the warning sound is changed according to the accelerator opening Acc, that is, the amount of depression of the driver's accelerator pedal 63, dulling of the driver's accelerator sense can be suppressed. Also, when the accelerator opening Acc increases and the excess torque Texc increases from the value 0, since the driver cannot recognize the warning sound emitted from the speaker 68 until the volume reaches the value S1 from the value 0, it is possible to suppress the driver from being surprised by the warning sound being emitted from the speaker 68 immediately after stepping on the accelerator pedal 63. Also, when the accelerator opening Acc decreases and the excess torque Texc is the value 0, since the volume emitted from the speaker 68 is the value S1, the driver can recognize the warning sound emitted from the speaker 68 until the excess torque Texc becomes the value 0. Thereby, the driver can surely return the accelerator pedal 63.

[0021] According to the electric vehicle 20 equipped with the warning device of the present embodiment described above, when the vehicle speed V is limited by the upper limit vehicle speed Vlim, the degree of the warning sound is changed according to the excess torque Texc obtained by subtracting the upper limit running torque Tdlim when the vehicle is running at the upper limit vehicle speed Vlim from the running required torque Td* based on the accelerator opening Acc, so that the dulling of the driver's accelerator feeling can be suppressed.

[0022] In the above embodiment, instead of the relationship illustrated in FIG. 3 for the relationship between the excess torque Texc and the required volume Vo*, when the excess torque Texc increases, the required volume Vo* may be changed at a predetermined rate, and when the excess torque Texc decreases, the required volume Vo* may be decreased stepwise. Also, without providing hysteresis, when the excess torque Texc is large, the required volume Vo* may be made larger than when it is small, or the required volume Vo* may be changed stepwise with respect to the excess torque Texc.

[0023] In the above embodiment, the upper limit vehicle speed Vlim is set as the vehicle speed corresponding to the 80th percentile when the vehicle speeds of a large number of vehicles running in the running section are collected and the collected vehicle speeds of the plurality of vehicles are arranged in ascending order. However, the upper limit vehicle speed Vlim may be determined in advance for each running section without collecting the vehicle speeds of a large number of vehicles running in the running section. Also, although the upper limit vehicle speed Vlim is set for each running section for each time zone such as early morning, daytime, and nighttime, it may be a constant value regardless of the time zone.

[0024] In the above embodiment, the electric vehicle 20 may be a hybrid vehicle capable of running with power from an engine and a motor.

[0025] The correspondence between the main elements of the embodiment and the main elements of the invention described in the column of means for solving the problems will be described. In the embodiment, the ECU 50 and the speaker 68 correspond to the "warning device".

[0026] Furthermore, the correspondence between the main elements of the embodiment and the main elements of the invention described in the section on means for solving the problem is merely an example to specifically explain the form in which the embodiment implements the invention described in the section on means for solving the problem, and does not limit the elements of the invention described in the section on means for solving the problem. In other words, the interpretation of the invention described in the section on means for solving the problem should be based on the description in that section, and the embodiment is merely one specific example of the invention described in the section on means for solving the problem.

[0027] Although the embodiments for implementing this disclosure have been described above, this disclosure is not limited in any way to these embodiments, and can of course be implemented in various forms without departing from the gist of this disclosure. [Industrial applicability]

[0028] This disclosure can be used in industries such as the manufacturing of vehicle warning devices. [Explanation of symbols]

[0029] 20 Electric vehicle, 22a, 22b Drive wheels, 24 Differential gear, 26 Drive shaft, 32 Motor, 34 Inverter, 36 Battery, 38 Power line, 40 Navigation system, 42 Main unit, 44 GPS antenna, 46 Display, 50 Electronic control unit (ECU), 60 Start switch, 61 Shift lever, 62 Shift sensor, 63 Accelerator pedal, 64 Accelerator sensor, 65 Brake pedal, 66 Brake sensor, 67 Vehicle speed sensor, 68 Speaker.

Claims

[Claim 1] A vehicle warning device that is installed on a vehicle capable of driving while limiting the vehicle speed to an upper speed limit, and which issues a warning, When the vehicle speed is limited to the upper limit vehicle speed, the degree of the warning is changed according to the excess torque obtained by subtracting the upper limit driving torque when the vehicle is driven at the upper limit vehicle speed from the driving request torque based on the accelerator opening. Vehicle warning system.

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