阅读说明：本技术 电动车辆 (Electric vehicle ) 是由 仙波快之 于 2021-06-01 设计创作，主要内容包括：本发明提出了在障碍物较多的区域和较少的区域中都能够舒适地行驶的电动车辆。电动车辆具有检测相对于检测到的障碍物的距离的障碍物检测装置、模式切换装置及最高速度限制装置。在第一模式下,在距离比第一基准值短的情况下,最高速度限制装置将电动车辆的最高速度限制为比距离比第一基准值长的情况下的值低的值,在第二模式下,在距离比第二基准值短的情况下,最高速度限制装置将最高速度限制为比距离比第二基准值长的情况下的值低的值。在距离从比第一基准值和第二基准值中的任一个短的值变化为比第一基准值和第二基准值中的任一个长的值的情况下,最高速度限制装置在第二模式下使最高速度在比第一模式早的定时上升。(The invention provides an electric vehicle which can comfortably run in an area with a large number of obstacles and an area with a small number of obstacles. The electric vehicle includes an obstacle detection device that detects a distance to a detected obstacle, a mode switching device, and a maximum speed limiting device. In the first mode, the top speed limiting device limits the top speed of the electric vehicle to a value lower than a value in a case where the distance is shorter than the first reference value, and in the second mode, the top speed limiting device limits the top speed to a value lower than a value in a case where the distance is longer than the second reference value. The maximum speed limiting means increases the maximum speed at a timing earlier than the first mode in the second mode when the distance changes from a value shorter than either of the first reference value and the second reference value to a value longer than either of the first reference value and the second reference value.)

1. An electric vehicle, wherein the electric vehicle has:

an obstacle detection device that detects an obstacle and detects a distance with respect to the detected obstacle;

mode switching means for switching a first mode and a second mode; and

a maximum speed limiting device that limits a maximum speed of the electric vehicle to a value lower than a value when the distance is shorter than a first reference value in the first mode, and limits the maximum speed to a value lower than a value when the distance is longer than a second reference value in the second mode,

the maximum speed limiting means increases the maximum speed at a timing earlier than the first mode in the second mode when the distance changes from a value shorter than any one of the first reference value and the second reference value to a value longer than any one of the first reference value and the second reference value.

2. The electric vehicle according to claim 1,

waiting for a predetermined time after the distance rises from a value shorter than the first reference value to the first reference value in the first mode, and then releasing the limitation of the maximum speed,

in the second mode, the limitation of the maximum speed is released when the distance rises from a value shorter than the second reference value to the second reference value.

3. The electric vehicle according to claim 1 or 2,

fixing the maximum speed to a first limit value in the case where the distance is shorter than the first reference value in the first mode,

in the second mode, when the distance is shorter than the second reference value, the control is performed such that the maximum speed increases from the first limit value as the distance becomes longer.

4. The electric vehicle according to any one of claims 1 to 3,

the second reference value is a value shorter than the first reference value.

5. The electric vehicle according to any one of claims 1 to 4, further comprising:

a position detection device that detects a position of the electric vehicle; and

a map storage that stores a map that determines a first area to which the first pattern is applied and a second area to which the second pattern is applied,

the mode switching means switches the first mode and the second mode based on the position detected by the position detecting means and the map.

6. The electric vehicle according to claim 5,

the electric vehicle further has a map updating device that sets, as the first region, a region including the position detected by the position detecting device in the map when a frequency of execution of the restriction and release of the restriction during traveling is higher than a threshold value, and sets, as the second region, a region including the position detected by the position detecting device in the map when the frequency of execution of the restriction and release of the restriction during traveling is lower than the threshold value.

7. The electric vehicle according to claim 5 or 6,

the electric vehicle further has current time determination means for determining a current time,

determining the first region and the second region by time in the mapping,

the mode switching means switches the first mode and the second mode based on the position detected by the position detecting means, the map, and the current time determined by the current time determining means.

8. The electric vehicle according to any one of claims 1 to 7,

the electric vehicle is also provided with an accelerator,

when the operating frequency of the accelerator is higher than a first predetermined value in the first mode, a parameter for controlling the maximum speed limiting means is rewritten so that the timing of increasing the maximum speed becomes earlier when the distance changes from a value shorter than the first reference value to a value longer than the first reference value in the first mode.

9. The electric vehicle according to any one of claims 1 to 8,

the electric vehicle is also provided with a brake,

when the operating frequency of the brake is higher than a second predetermined value in the first mode, a parameter for controlling the maximum speed limiting means is rewritten so that the timing of increasing the maximum speed becomes later when the distance changes from a value shorter than the first reference value to a value longer than the first reference value in the first mode.

Technical Field

The technology disclosed herein relates to an electric vehicle.

Background

Patent document 1 discloses an electric vehicle that a user rides on and travels. In such an electric vehicle, when an obstacle (e.g., an object present on a road surface, a pedestrian, or the like) is detected, control for limiting the maximum speed of the electric vehicle may be performed. When the vehicle is far from the obstacle, the limitation of the maximum speed is released. When passing near an obstacle, the maximum speed is limited, thereby enabling appropriate travel.

Prior art documents

Patent document

Patent document 1: japanese patent laid-open publication No. 2018-062282

Disclosure of Invention

Problems to be solved by the invention

In an electric vehicle that limits the maximum speed when an obstacle is detected, when the vehicle travels through an area with many obstacles, the limitation of the maximum speed and the cancellation thereof are repeated. As a result, the electric vehicle repeats deceleration and acceleration, and riding comfort is deteriorated. In order to prevent this, if the limitation of the maximum speed is continued for a certain period of time even when the vehicle is far from the obstacle, the limitation of the maximum speed is not released for a while after passing through the obstacle while traveling through an area with few obstacles, and this causes a problem of poor operability. In the present specification, an electric vehicle that can travel comfortably in both a region with a large number of obstacles and a region with a small number of obstacles is proposed.

Means for solving the problems

An electric vehicle disclosed in the present specification includes an obstacle detection device, a mode switching device, and a maximum speed limiting device. The obstacle detection device detects an obstacle and detects a distance with respect to the detected obstacle. The mode switching means switches a first mode and a second mode. In the first mode, the top speed limiting device limits the top speed of the electric vehicle to a value lower than a value in a case where the distance is shorter than a first reference value, and in the second mode, the top speed limiting device limits the top speed to a value lower than a value in a case where the distance is longer than a second reference value. The maximum speed limiting means increases the maximum speed at a timing earlier than the first mode in the second mode when the distance changes from a value shorter than any one of the first reference value and the second reference value to a value longer than any one of the first reference value and the second reference value.

In the electric vehicle, the first mode and the second mode can be switched. The first mode can be selected when the vehicle travels through an area with a large number of obstacles, and the second mode can be selected when the vehicle travels through an area with a small number of obstacles. The switching between the first mode and the second mode may be performed by a user operation or may be performed automatically. When the electric vehicle moves to a position close to an obstacle, the maximum speed is limited. When the electric vehicle travels from a position close to the obstacle to a position far from the obstacle, the limit of the maximum speed is released by changing the distance to the obstacle detected by the obstacle detecting device from a value shorter than either one of the first reference value and the second reference value to a value longer than either one of the first reference value and the second reference value. At this time, in the second mode, the maximum speed rises at a timing earlier than that in the first mode. Therefore, by selecting the second mode in the region with few obstacles, it is possible to accelerate quickly after passing through the obstacle, and it is possible to travel comfortably. Further, when the distance to the obstacle changes from a value shorter than either of the first reference value and the second reference value to a value longer than either of the first reference value and the second reference value, the maximum speed in the first mode rises at a timing later than the second mode. Therefore, it is possible to suppress the maximum speed from increasing when another obstacle is detected after passing through the obstacle. Therefore, by selecting the first mode in the region with many obstacles, it is possible to suppress unnecessary acceleration and to travel comfortably.

Drawings

Fig. 1 is a diagram showing an electric vehicle of embodiment 1.

Fig. 2 is a graph showing the highest speed Vmax in the first mode and the second mode.

Fig. 3 is a flowchart showing the process of controlling the maximum speed Vmax in embodiment 1.

Fig. 4 is a graph showing a first modification of the maximum speed Vmax.

Fig. 5 is a graph showing a second modification of the maximum speed Vmax.

Fig. 6 is a graph showing a third modification of the maximum speed Vmax.

Fig. 7 is a diagram showing an electric vehicle of embodiment 2.

Fig. 8 is a flowchart showing a process of registering the density of obstacles in the obstacle map in embodiment 2.

Fig. 9 is a flowchart showing the process of controlling the maximum speed Vmax in embodiment 2.

Fig. 10 is a diagram showing an electric vehicle of embodiment 3.

Fig. 11 is a flowchart showing a process of registering the density of obstacles in the obstacle map in embodiment 3.

Fig. 12 is a flowchart showing the process of controlling the highest speed Vmax in embodiment 3.

Fig. 13 is a flowchart showing a process of adjusting the standby time T in embodiment 4.

Description of reference numerals

10: electric vehicle

12: obstacle sensor

14: electric motor

16: mode change-over switch

18: accelerator

20: brake

22: control device

Detailed Description

The technical elements of the electric vehicle disclosed in the present specification are described below. The following technical elements are independent and useful.

In the electrically powered vehicle disclosed in the present specification, in the first mode, after waiting for a predetermined time after the distance increases from a value shorter than the first reference value to the first reference value, the limitation of the maximum speed may be released, and in the second mode, the limitation of the maximum speed may be released when the distance increases from a value shorter than the second reference value to the second reference value.

According to this configuration, when the distance to the obstacle changes from a value shorter than either of the first reference value and the second reference value to a value longer than either of the first reference value and the second reference value, the maximum speed can be increased at a timing earlier than that in the first mode in the second mode.

In the electrically powered vehicle according to the example disclosed in the present specification, in the first mode, the maximum speed may be fixed to a first limit value when the distance is shorter than the first reference value. In the second mode, when the distance is shorter than the second reference value, the control is performed such that the maximum speed increases from the first limit value as the distance becomes longer.

According to this configuration, when the distance to the obstacle changes from a value shorter than either of the first reference value and the second reference value to a value longer than either of the first reference value and the second reference value, the maximum speed can be increased at a timing earlier than that in the first mode in the second mode.

In the electrically powered vehicle according to the example disclosed in the present specification, the second reference value may be a value shorter than the first reference value.

According to this configuration, when the distance to the obstacle changes from a value shorter than either of the first reference value and the second reference value to a value longer than either of the first reference value and the second reference value, the maximum speed can be increased at a timing earlier than that in the first mode in the second mode.

In the electric vehicle according to the example disclosed in the present specification, the electric vehicle may further include: a position detection device that detects a position of the electric vehicle; and a map storage device that stores a map that determines a first area to which the first pattern is applied and a second area to which the second pattern is applied. In addition, the mode switching means may switch the first mode and the second mode based on the position detected by the position detecting means and the map.

According to this configuration, the first mode and the second mode can be automatically switched according to the position of the electric vehicle.

In the electric vehicle according to the example disclosed in the present specification, the electric vehicle may further include a map updating device that sets, as the first region, a region including the position detected by the position detecting device in the map when a frequency of execution of the restriction and release of the restriction during traveling is higher than a threshold value, and sets, as the second region, a region including the position detected by the position detecting device in the map when the frequency of execution of the restriction and release of the restriction during traveling of the electric vehicle is lower than the threshold value.

According to this configuration, the region with a large number of obstacles can be set as the first region, and the region with a small number of obstacles can be set as the second region.

The electric vehicle according to the example disclosed in the present specification may further include a current time specifying device that specifies the current time. The first area and the second area may be determined by time in the map. The mode switching means may switch the first mode and the second mode based on the position detected by the position detecting means, the map, and the current time determined by the current time determining means.

According to this configuration, even when the number of obstacles varies with time, the first mode and the second mode can be switched as appropriate.

The electric vehicle according to the example disclosed in the present specification may further include an accelerator. In the case where the operating frequency of the accelerator is higher than a first predetermined value in the first mode, the parameter for controlling the maximum speed may be rewritten so that the timing of increasing the maximum speed becomes earlier when the distance changes from a value shorter than the first reference value to a value longer than the first reference value in the first mode.

According to this configuration, the timing of the rise in the maximum speed in the first mode can be made earlier for a user who feels that the timing of the rise in the maximum speed in the first mode is late.

The electric vehicle disclosed in the present specification may further include a brake. When the operating frequency of the brake is higher than a second predetermined value in the first mode, the parameter for controlling the maximum speed may be rewritten so that the timing of increasing the maximum speed becomes later when the distance changes from a value shorter than the first reference value to a value longer than the first reference value in the first mode.

According to this configuration, it is possible to delay the timing of the rise of the highest speed in the first mode for a user who feels that the timing of the rise of the highest speed in the first mode is early.

Example 1

An electric vehicle 10 according to embodiment 1 shown in fig. 1 is an electric vehicle on which a user rides. In fig. 1, the electric vehicle 10 has three wheels, but one or two wheels of the electric vehicle may be provided, or four or more wheels of the electric vehicle may be provided. The electric vehicle 10 is an electric vehicle that moves at a speed (for example, a speed of 10km or less per hour) similar to that of a pedestrian in an area where the pedestrian walks such as a sidewalk (so-called walking area ev). As shown in fig. 1, the electric vehicle 10 includes an obstacle sensor 12, a motor 14, a mode selector switch 16, an accelerator 18, a brake 20, and a control device 22.

The obstacle sensor 12 is a sensor that detects obstacles around the electric vehicle 10. Obstacles include objects on the road (vehicles, fences, trees, etc.) and pedestrians. The obstacle sensor 12 is an ultrasonic or optical object detection sensor. The obstacle sensor 12 detects an obstacle around the electric vehicle 10 during traveling of the electric vehicle 10. When detecting an obstacle, the obstacle sensor 12 detects a distance Ls to the obstacle (i.e., a distance between the electric vehicle 10 and the obstacle). The obstacle sensor 12 performs detection of an obstacle and detection of the distance Ls at predetermined cycles during traveling of the electric vehicle 10.

The electric motor 14 is driven by receiving electric power from a battery built in the electric vehicle 10. The electric vehicle 10 travels by being driven by the electric motor 14. The motor 14 is controlled by a control device 22.

The mode changeover switch 16 is a switch operated by the user. The first mode and the second mode are switched by the mode changeover switch 16. The process performed by the control device 22 varies between the first mode and the second mode.

The acceleration is instructed to the control device 22 by the user operating the accelerator 18.

The electric vehicle 10 is decelerated by the user operating the brake 20.

The control device 22 is connected to the obstacle sensor 12, the motor 14, the mode selector switch 16, the accelerator 18, and the brake 20. The control device 22 controls the motor 14 based on signals input from the obstacle sensor 12, the mode switching switch 16, the accelerator 18, and the brake 20. The control device 22 drives the electric motor 14 in accordance with a signal input from the accelerator 18, thereby controlling the speed V (moving speed) of the electric vehicle 10. Further, the control device 22 sets the maximum speed Vmax of the electric vehicle 10 based on the signal input from the obstacle sensor 12 and the signal input from the mode selector switch 16. The control device 22 controls the speed V of the electric vehicle 10 in a range of the maximum speed Vmax or less.

The controller 22 changes the maximum speed Vmax according to the distance Ls to the obstacle. The control device 22 stores graphs G1 and G2 shown in fig. 2. The graphs G1, G2 specify the relationship between the distance Ls to the obstacle and the maximum speed Vmax. The controller 22 sets the maximum speed Vmax according to the graphs G1 and G2. The control device 22 sets the maximum speed Vmax according to the map G1 when the first mode is selected by the mode switch 16, and sets the maximum speed Vmax according to the map G2 when the second mode is selected by the mode switch 16.

In the first mode (graph G1), when the distance Ls is shorter than the first reference value Ls1, the control device 22 limits the maximum speed Vmax to a lower value than when the distance Ls is equal to or greater than the first reference value Ls 1. More specifically, in the first mode, the maximum speed Vmax when the distance Ls is equal to or greater than the first reference value Ls1 is the value VmaxH, and the maximum speed Vmax when the distance Ls is shorter than the first reference value Ls1 is the value VmaxL. The value VmaxL is lower than VmaxH. That is, the control device 22 limits the maximum speed Vmax to the value VmaxL when the distance Ls is shorter than the first reference value Ls 1. In the first mode, the highest speed Vmax when the distance Ls is shorter than the first reference value Ls1 is fixed to a value VmaxL.

In the second mode (graph G2), when the distance Ls is shorter than the second reference value Ls2, the control device 22 limits the maximum speed Vmax to a lower value than when the distance Ls is equal to or greater than the second reference value Ls 2. More specifically, in the second mode, the maximum speed Vmax when the distance Ls is equal to or greater than the second reference value Ls2 is a value VmaxH (a value equal to the value VmaxH in the first mode). In fig. 2, the second reference value Ls2 is equal to the first reference value Ls 1. In the second mode, the highest speed Vmax when the distance Ls is shorter than the second reference value Ls2 varies depending on the distance Ls. When the distance Ls is shorter than the third reference value Ls3, the maximum speed Vmax is fixed to a value VmaxL (a value equal to the value VmaxL of the first mode). When the distance Ls is within the range R1 that is equal to or greater than the third reference value Ls3 and shorter than the second reference value Ls2, the longer the distance Ls becomes, the higher the maximum speed Vmax becomes. In the range R1, the maximum speed Vmax linearly increases from the value VmaxL to the value VmaxH as the distance Ls becomes longer.

Next, a process executed by the control device 22 during traveling of the electric vehicle 10 will be described. In embodiment 1, the user operates the mode selector switch 16 to switch between the first mode and the second mode. The user selects the first mode using the mode changing switch 16 when traveling through an area with many obstacles (for example, an area with a narrow road surface or an area with many pedestrians), and selects the second mode using the mode changing switch 16 when traveling through an area with few obstacles. The control device 22 repeatedly executes the processing shown in fig. 3 during traveling of the electric vehicle 10.

In step S2, control device 22 receives a signal (a signal showing which of the first mode and the second mode is selected) from mode changing switch 16.

Next, in step S4, the control device 22 receives the distance Ls from the obstacle sensor 12. When the obstacle sensor 12 detects a plurality of obstacles, the control device 22 obtains a distance from the nearest obstacle as the distance Ls. When the obstacle sensor 12 does not detect an obstacle, the control device 22 acquires the maximum value among the values that can be acquired as the distance Ls.

Next, in step S6, the control device 22 determines whether the currently selected mode is the first mode or the second mode based on the signal received in step S2. If the first mode is selected, the control device 22 executes steps S8 to S14. If the second mode is selected, the control device 22 executes step S16.

If the first mode is selected, the control device 22 executes step S8. In step S8, the control device 22 determines a value (hereinafter referred to as a command value) to be set next to the maximum speed Vmax based on the map G1 shown in fig. 2 and the distance Ls acquired in step S4. As shown in the graph G1, the control device 22 determines the value VmaxL as the command value for the maximum speed Vmax when the distance Ls is shorter than the first reference value Ls 1. When the distance Ls is equal to or greater than the first reference value Ls1, the control device 22 determines the value VmaxH as the command value for the maximum speed Vmax.

Next, the control device 22 makes a determination regarding the distance Ls in step S10. In step S10, the control device 22 determines whether the distance Ls increases from a value less than the first reference value Ls1 to a value equal to or greater than the first reference value Ls1, based on the distance Ls obtained in the most recently executed step S4 and the distance Ls obtained in the step S4 preceding it. In the case of yes in step S10, the control device 22 executes step S14 after waiting for the time T in step S12. If no in step S10, the control device 22 executes step S14 without waiting.

In step S14, the control device 22 updates the highest speed Vmax to the command value determined in step S8. Therefore, after step S14, the speed V of the electric vehicle 10 is controlled within the range of the maximum speed Vmax updated in step S14 or less.

When the second mode is selected, the control device 22 executes step S16. In step S16, the control device 22 determines the command value for the highest speed Vmax based on the map G2 shown in fig. 2 and the distance Ls acquired in step S4. That is, the control device 22 determines the value VmaxL as the command value for the maximum speed Vmax in the case where the distance Ls is smaller than the third reference value Ls 3. When the distance Ls is within the range R1, the control device 22 determines the value within the range R1 corresponding to the distance Ls (a value greater than the value VmaxL and equal to or less than the value VmaxH) as the command value for the maximum speed Vmax. When the distance Ls is equal to or greater than the second reference value Ls2, the control device 22 determines the value VmaxH as the command value for the maximum speed Vmax. In step S16, when determining the command value for the maximum speed Vmax, the control device 22 updates the maximum speed Vmax to the determined command value. Therefore, after step S16, the speed V of the electric vehicle 10 is controlled within the range of the maximum speed Vmax updated in step S16 or less.

Next, the operation when the electric vehicle 10 is away from an obstacle in each of the first mode and the second mode will be described.

First, the first mode is explained. As described above, during the travel of the electric vehicle 10, the control device 22 repeatedly executes the process of fig. 3. In the first mode, steps S2, S4, S6, S8, S10, S14 are performed. In addition, in the first mode, step S12 is selectively performed. In the case where the electric vehicle 10 travels through the vicinity of the obstacle, the distance Ls acquired in step S4 is shorter than the first reference value L1. In this case, in the first mode, in step S8, the value VmaxL is determined as the command value for the maximum speed Vmax. While the electric vehicle 10 is traveling near the obstacle, it is determined as no in step S10, and the set value VmaxL is set as the maximum speed Vmax in step S14.

After that, the electric vehicle 10 travels, so that the distance Ls to the obstacle gradually increases. While the distance Ls is shorter than the first reference value L1, steps S2, S4, S6, S8, S10, and S14 are repeatedly executed, and the maximum speed Vmax is maintained at the value VmaxL.

After that, when the distance Ls to the obstacle increases to the first reference value L1 by the electric vehicle 10 traveling, the value VmaxH is determined as the command value of the maximum speed Vmax in step S8. In this case, the distance Ls in the previous processing is smaller than the first reference value L1, and the distance Ls in the current processing is equal to or greater than the first reference value L1, so that the determination in step S10 is yes. Therefore, the control device 22 executes step S14 after waiting for the time T in step S12. In step S14, the highest speed Vmax is updated to the value VmaxH determined in step S8. That is, the maximum speed Vmax rises from the value VmaxL to the value VmaxH.

After that, the electric vehicle 10 travels, so that the distance Ls to the obstacle increases. While the distance Ls is longer than the first reference value L1, steps S2, S4, S6, S8, S10, and S14 are repeatedly executed, and the maximum speed Vmax is maintained at the value VmaxH.

In this way, in the first mode, the maximum speed Vmax is fixed to the lower value VmaxL for a period in which the distance Ls is shorter than the first reference value L1. In the first mode, when the distance Ls increases from a value shorter than the first reference value L1 to a value equal to or greater than the first reference value L1, the control device 22 waits for the time T and then increases the maximum speed Vmax from the value VmaxL to the value VmaxH. In this way, in the first mode, when the distance Ls is shorter than the first reference value L1, the maximum speed Vmax is fixed to the lower value VmaxL, and when the distance Ls reaches the first reference value L1, the standby time T is set, and then the maximum speed Vmax is raised to the value VmaxH. Therefore, in the first mode, when the distance Ls increases from a value shorter than the first reference value L1 to a value longer than the first reference value L1, the timing at which the highest speed Vmax increases is late.

Next, the second mode is explained. In the second mode, steps S2, S4, S6, S16 are performed. In the case where the electric vehicle 10 travels through the immediate vicinity of the obstacle, the distance Ls acquired in step S4 is shorter than the third reference value Ls 3. In this case, in the second mode, in step S16, the maximum speed Vmax is set to the value VmaxL. The maximum speed Vmax is maintained at the value VmaxL while the distance Ls is shorter than the third reference value L3.

Thereafter, when the distance Ls reaches the third reference value Ls3 by the electric vehicle 10 traveling, the maximum speed Vmax is set to a value corresponding to the distance Ls (a value within the range R1 of the graph G2 of fig. 2) in step S16. When the distance Ls gradually increases within the range R1 while the electric vehicle 10 is traveling, the maximum speed Vmax gradually increases with an increase in the distance Ls.

Thereafter, when the distance Ls reaches the second reference value Ls2 by the electric vehicle 10 traveling, the maximum speed Vmax is set to the value VmaxH in step S16. While the distance Ls is equal to or greater than the second reference value L2, the maximum speed Vmax is maintained at the value VmaxH.

In this way, in the second mode, when the distance Ls is within the range R1 shorter than the second reference value L2, the maximum speed Vmax increases with an increase in the distance Ls. In addition, in the second mode, the increase of the maximum speed Vmax is performed without a standby time. Therefore, when the distance Ls increases from a value shorter than the first reference value L1 and the second reference value L2 to a value longer than these, the maximum speed Vmax rises at a timing earlier than the first mode in the second mode.

As described above, when the distance Ls increases, the maximum speed Vmax rises at a timing earlier than that in the first mode in the second mode. Therefore, when the vehicle travels through an area with few obstacles, the second mode is selected, so that the electric vehicle 10 can be accelerated as soon as possible after passing through an obstacle. This enables comfortable traveling. Further, by selecting the first mode when traveling through an area with many obstacles, it is possible to prevent the electric vehicle 10 from accelerating immediately after passing through an obstacle. This can suppress repetition of acceleration and deceleration when the vehicle passes through an obstacle and then encounters the next obstacle. Therefore, comfortable running can be performed. As described above, according to the electric vehicle 10 of embodiment 1, comfortable traveling can be performed in both a region with few obstacles and a region with many obstacles.

In embodiment 1, the rise rate of the maximum speed Vmax when the distance Ls is shorter than the first reference value Ls1 and the second reference value Ls2 (the rise rate of the maximum speed Vmax when the distance Ls increases) is differentiated, so that the maximum speed Vmax rises earlier in the second mode than in the first mode. In the first mode, the maximum speed Vmax is increased after the standby time T, while in the second mode, the maximum speed Vmax is increased without the standby time, and thus in the second mode, the maximum speed Vmax is also increased at a timing earlier than that in the first mode. However, only one of them may be adopted. For example, in the case where the graphs G1, G2 are set as shown in fig. 2, the maximum speed Vmax can be updated without standby time in either the first mode or the second mode (i.e., step S12 of fig. 3 can be omitted). For example, when the maximum speed Vmax is increased from the value VmaxL to the value VmaxH while the graphs G1 and G2 are made the same as shown in fig. 4, the maximum speed Vmax may be increased at a timing earlier than the first mode in the second mode by applying the standby time in the first mode and not applying the standby time in the second mode.

In example 1, the first reference value Ls1 is equal to the second reference value Ls2, but the second reference value Ls2 may be shorter than the first reference value Ls1 as shown in fig. 5. In this configuration, the maximum speed Vmax can be increased at a timing earlier than that in the first mode in the second mode. As shown in fig. 6, the maximum speed Vmax may be changed stepwise in table G2 in the same manner as in table G1, with the second reference value Ls2 being shorter than the first reference value Ls 1. In this configuration, the maximum speed Vmax can be increased at a timing earlier than that in the first mode in the second mode. In the first mode of fig. 5 and 6, the standby time may be applied or may not be applied.

Example 2

The electric vehicle 200 of embodiment 2 shown in fig. 7 has a GPS (global positioning system) device 216 in place of the mode changeover switch 16. In the electric vehicle 200 according to embodiment 2, the control device 22 stores an obstacle map. The other structure of the electric vehicle 200 of embodiment 2 is the same as that of the electric vehicle 10 of embodiment 1. The GPS device 216 receives GPS signals from the outside and determines the current position of the electric vehicle 200.

In embodiment 2, the control device 22 registers information of an obstacle in the obstacle map by area during traveling of the electric vehicle 200. In the region where the information of the obstacle is not registered, the control device 22 controls the maximum speed Vmax in accordance with the second mode (i.e., the graph G2 of fig. 2). Fig. 8 shows a process in which the control device 22 registers information of an obstacle in the obstacle map. Control device 22 repeatedly executes the processing shown in fig. 8 during traveling of electric powered vehicle 200.

In step S210, the control device 22 receives the current position of the electric vehicle 200 (hereinafter referred to as the current position) from the GPS device 216. Next, control device 22 monitors the running state of electric powered vehicle 200 in step S212. In step S212, when the electric vehicle 200 approaches the obstacle, the distance Ls becomes shorter than the reference values Ls1, Ls2, and the limitation of the maximum speed Vmax is performed. In step S212, when the electric vehicle 200 moves away from the obstacle, the distance Ls becomes equal to or greater than the reference values Ls1 and Ls2, and the limitation of the maximum speed Vmax is released. In step S212, the controller 22 measures the frequency F at which the limitation of the maximum speed Vmax is executed and released. In step S214, control device 22 determines whether frequency F is higher than threshold Fth. If the determination in step S214 is yes, the control device 22 specifies an area including the current position (the current position specified in step S210) from the obstacle map in step S216, and registers an identifier a1 (an identifier indicating that there are many obstacles and the first pattern should be applied) in the area. When it is determined as no in step S214, the control device 22 specifies an area including the current position from the obstacle map and registers an identifier a2 (an identifier indicating that there are few obstacles and the second pattern should be applied) in the area in step S218. By the control device 22 repeatedly executing the processing of fig. 8 during the travel of the electric vehicle 200, the identifiers a1, a2 are registered for each area in the obstacle map.

In this way, in embodiment 2, the controller 22 determines the number (density) of obstacles based on the frequency F of execution and release of the limitation of the maximum speed Vmax, and registers the identifiers a1 and a2 for the respective areas. Therefore, the identifiers a1, a2 can be easily and appropriately registered in the respective areas. Therefore, the obstacle map showing which of the first mode and the second mode should be applied can be appropriately created.

Fig. 9 shows a process in which the control device 22 controls the maximum speed Vmax in embodiment 2. The process of fig. 9 is the same as the process of fig. 3, except that step S202 is different from step S2.

In step S202, the control device 22 receives the current position of the electric vehicle 200 from the GPS device 216. Then, an area (hereinafter, referred to as a current area) including the received current position is determined in the obstacle map, and an identifier of the current area is determined. The control device 22 selects the first mode when the current region has the identification symbol a1, and selects the second mode when the current region has the identification symbol a 2. Thereafter, the control device 22 executes the processing of step S4 and subsequent steps in the same manner as in embodiment 1.

Thus, in embodiment 2, the control device 22 automatically selects the first mode and the second mode based on the current position and the obstacle map received from the GPS device 216. Therefore, the user does not need to manually switch the first mode and the second mode.

Example 3

An electrically powered vehicle 300 according to embodiment 3 shown in fig. 10 has a configuration in which a current time determination device 316 is further added to the electrically powered vehicle 200 according to embodiment 2. The current time determination means 316 determines the current time.

In embodiment 3, the control device 22 registers information of obstacles in the obstacle map by area and by time during the travel of the electric vehicle 300. Control device 22 repeatedly executes the processing shown in fig. 11 during traveling of electric powered vehicle 300.

In step S310, the control device 22 receives the current position of the electric vehicle 300 from the GPS device 216. In step S310, the control device 22 receives the current time from the current time determination device 316. In step S312, control device 22 monitors the traveling state of electric powered vehicle 300, as in step S212 of embodiment 2. That is, the controller 22 measures the frequency F at which the limitation of the maximum speed Vmax is executed and released in step S312. In step S314, control device 22 determines whether frequency F is higher than threshold Fth. If the determination result is yes in step S314, the control device 22 determines the current area from the obstacle map in step S316. Then, the identifier a1 is registered as the identifier of the current time of the current area (the current time received in step S311). If it is determined as no in step S314, the control device 22 registers the identifier a2 as the identifier at the current time of the current area in step S318. By repeatedly executing the processing of fig. 11 by the control device 22 during the travel of the electric vehicle 300, the identifiers a1, a2 are registered in the obstacle map for each area and time.

In this way, in embodiment 3, the control device 22 registers the identifiers a1, a2 by region and by time.

Fig. 12 shows a process in which the control device 22 controls the maximum speed Vmax in embodiment 3. The process of fig. 12 is the same as the process of fig. 9 except that step S302 is different from step S202.

In step S302, the control device 22 receives the current position of the electric vehicle 300 from the GPS device 216, and receives the current time from the current time determination device 316. Then, the identification symbol corresponding to the current area (the area including the current position received from the GPS device 216) and the current time is determined from the obstacle map. The control device 22 selects the first mode when the determined identification symbol is identification symbol a1, and selects the second mode when the determined identification symbol is identification symbol a 2. Thereafter, the control device 22 executes the processing of step S4 and subsequent steps in the same manner as in embodiments 1 and 2.

In this way, in embodiment 3, the control device 22 automatically selects the first mode and the second mode based on the current position received from the GPS device 216, the current time received from the current time determination device 316, and the obstacle map. The number of obstacles (e.g., the number of pedestrians) varies according to the time of day. According to the electric vehicle 300 of embodiment 3, even in the case where the number of obstacles changes according to the time, the first mode and the second mode can be automatically selected as appropriate.

Example 4

In embodiment 4, the electric vehicle controls the maximum speed Vmax in accordance with the processing of any one of embodiments 1, 2, and 3 (i.e., any one of fig. 3, 9, and 12). In embodiment 4, while the electric vehicle is running in the first mode, the control device 22 measures the operating frequencies of the accelerator 18 and the brake 20. The parameters in the first mode are then adjusted based on the measured operating frequency. While traveling in the first mode, control device 22 repeatedly executes the processing shown in fig. 13.

In step S410, control device 22 monitors the traveling state of the electric vehicle in the first mode. That is, the control device 22 measures the frequency C1 at which the user turns the accelerator 18 on/off and the frequency B1 at which the user uses the brake 20 during the running of the electric vehicle. Next, in step S411, the control device 22 determines whether the frequency C1 is higher than the threshold Cth and the frequency B1 is higher than the threshold Bth. The frequency C1 at which the accelerator 18 is opened is higher than the threshold Cth, which means that the user feels that the maximum speed Vmax rises at a later timing when the limitation of the maximum speed Vmax is released. The frequency B1 at which the brake 20 is used is higher than the threshold value Bth, which means that the user feels that the maximum speed Vmax rises earlier when the limitation of the maximum speed Vmax is released.

When the frequency C1 is higher than the threshold Cth and the frequency B1 is equal to or lower than the threshold Bth, it is considered that the user feels that the timing at which the maximum speed Vmax rises is late. Therefore, in this case, the control device 22 shortens the time T (the standby time of step S12 in fig. 3, 9, and 12) to 0.9 times the current time in step S412.

In the case where the frequency B1 is higher than the threshold value Bth, it is considered that the user feels that the timing at which the maximum speed Vmax rises is earlier. In this case, therefore, the control device 22 extends the time T to 1.1 times the current time in step S414.

When the frequency C1 is equal to or lower than the threshold Cth and the frequency B1 is equal to or lower than the threshold Bth, it is considered that the user has an appropriate timing at which the user feels that the maximum speed Vmax increases. In this case, therefore, the control device 22 maintains the time T at the current value in step S416.

After executing any of steps S412, 414, 416, the control device 22 executes step S418. In step S418, the control device 22 determines whether or not the time T is within a range of the lower limit value Tmin or more and the upper limit value Tmax or less. If it is determined as yes in step S418, the control device 22 directly adopts the time T determined in any of steps 412, 414, and 416. If the time T is smaller than the lower limit value Tmin, the control device 22 corrects the time T to the lower limit value Tmin in step S420. When the time T is greater than the upper limit value Tmax, the control device 22 corrects the time T to the upper limit value Tmax in step S420.

As described above, in the electric vehicle of embodiment 4, the time T is changed according to the running state of the electric vehicle. Therefore, the time T is appropriately changed to a value appropriate for the user. Therefore, when the limit of the maximum speed Vmax is released as the distance Ls increases during traveling in the first mode, the maximum speed Vmax increases at a timing suitable for the user. Therefore, the user can drive more comfortably.

In embodiment 4, the time T is adjusted in steps S412, 414, and 416. However, the timing at which the maximum speed Vmax rises may be adjusted by changing other parameters in the first mode, such as the first reference value Ls1 and the shape of the graph G1. For example, when the timing of increasing the maximum speed Vmax is delayed, the first reference value Ls1 may be further extended. For example, when the maximum speed Vmax is increased early, the first reference value Ls1 may be further shortened.

The embodiments have been described in detail above, but these are merely examples and do not limit the scope of the claims. The techniques recited in the claims include various modifications and changes made to the specific examples illustrated above. The technical elements described in the specification or the drawings exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. The techniques illustrated in the present specification and the drawings are techniques for achieving a plurality of objects at the same time, and achieving one of the objects has technical usefulness.