JP2015100225A - Car speed limit device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a car speed limit device for assuring acceleration feeling up to reaching a limit car speed and stableness feeling during travel near the limit car speed.SOLUTION: A request torque is limited by a limit mode in which, when a vehicle exceeds a preset limit car speed, a request torque obtained based on car speed and accelerator open degree is set to be zero, and if the vehicle is below the limit car speed after reaching the limit car speed, a request torque is limited based on a gain that decreases according to car speed (S2→S4→S5).

Description

  The present invention relates to a vehicle speed limiting device that limits the speed of a vehicle.

  2. Description of the Related Art A vehicle having a vehicle speed limiting device that can be controlled so that torque cannot be output beyond a certain speed is known. Among such vehicles, there is also a vehicle in which an upper limit value of the vehicle speed that can be traveled, that is, a so-called limited vehicle speed is set lower than that of a general vehicle depending on applications.

Japanese Patent No. 3106968

  In the vehicle speed limiting device as described above, the vehicle speed is limited to a constant value by limiting the required torque from the device to the drive system such as the internal combustion engine or the motor. In that case, the vehicle speed is calculated from the driver's accelerator operation or the like. Generally, a method of multiplying the required torque by a gain according to the vehicle speed. If the gain corresponding to the vehicle speed is obtained linearly at this time, the feeling of acceleration until the vehicle reaches the predetermined speed limit and the stability when traveling near the speed limit are in a trade-off relationship.

  For example, as shown in FIG. 6, when the gain is changed from 1 to 0 at 50 km / h of the limit vehicle speed, in order to give a feeling of acceleration until reaching the limit vehicle speed as much as possible, the gain gradient of the limit vehicle speed is set to be large. The gain becomes 0 at 50 km / h, and the gain becomes 1 at a lower speed of 49 km / h. Therefore, the gain near the limit vehicle speed changes abruptly, and torque hunting occurs near the limit vehicle speed. As a result, rattling of the vehicle occurs, and the sense of stability during travel is impaired.

  On the other hand, as shown in FIG. 7, in order to avoid torque hunting during traveling, the gain is reduced as the vehicle speed increases in the speed range of 40 to 50 km / h in order to set the gain gradient for limiting the vehicle speed small. As a result, the speed range for limiting the vehicle speed becomes wider, and the acceleration feeling in that speed range is lost.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a vehicle speed limiting device that can ensure a sense of acceleration until the vehicle reaches the limit vehicle speed and a sense of stability when traveling near the limit vehicle speed.

A vehicle speed limiting device according to a first invention for solving the above-mentioned problem is as follows.
Vehicle speed detecting means for detecting the vehicle speed of the vehicle;
An accelerator opening detecting means for detecting an accelerator opening of the accelerator pedal of the vehicle;
Control means for controlling the driving means of the vehicle based on the required speed calculated based on the vehicle speed and the accelerator opening;
The control means sets the required torque to 0 when the vehicle exceeds a preset limit vehicle speed, and when the vehicle reaches the limit vehicle speed and falls below the limit vehicle speed, The required torque is limited by a limiting mode in which the required torque is limited based on a gain that decreases accordingly.

A vehicle speed limiting device according to a second invention for solving the above-mentioned problems is as follows.
In the vehicle speed limiting device according to the first invention,
The control means cancels the restriction mode based on a predetermined condition when the restriction mode is being implemented.

A vehicle speed limiting device according to a third invention for solving the above-described problem is
In the vehicle speed limiting device according to the second invention,
The predetermined condition is characterized in that the vehicle speed is equal to or lower than a predetermined vehicle speed smaller than the limit vehicle speed.

A vehicle speed limiting device according to a fourth invention for solving the above-described problem is
In the vehicle speed limiting device according to the second invention,
The predetermined condition is characterized in that the accelerator opening is equal to or less than a predetermined value.

A vehicle speed limiting device according to a fifth invention for solving the above-described problem is
In the vehicle speed limiting device according to the fourth invention,
The fixed value is the accelerator opening at which the required torque is 0 or less.

A vehicle speed limiting device according to a sixth invention for solving the above-described problems is as follows.
In the vehicle speed limiting device according to the fourth invention,
The fixed value is set to 0.
That is, when the accelerator opening is 0, that is, when the accelerator is off.

A vehicle speed limiting device according to a seventh invention for solving the above-described problem is
In the vehicle speed limiting device according to the second invention,
The predetermined condition is characterized in that the vehicle moves forward and the required torque is 0 or less.

  According to the present invention, it is possible to ensure a sense of stability when traveling near the limit vehicle speed as well as a feeling of acceleration until reaching the limit vehicle speed.

It is a schematic structure figure showing an example of an embodiment of a vehicle speed limiting device concerning the present invention. 2 is a flowchart illustrating an example (Example 1) of control contents executed by the vehicle speed limiting device shown in FIG. 1. It is a figure explaining the control based on the flowchart shown in FIG. It is a flowchart explaining the other example (Example 2) of the control content implemented with the vehicle speed limiting apparatus shown in FIG. It is a figure explaining the control based on the flowchart shown in FIG. It is a figure explaining the problem at the time of setting the gain gradient of a vehicle speed restriction large in the conventional vehicle speed restriction device. It is a figure explaining the problem at the time of setting the gain gradient of a vehicle speed restriction | limiting small in the conventional vehicle speed restriction | limiting apparatus.

  Hereinafter, an embodiment of a vehicle speed limiting device according to the present invention will be described with reference to FIGS. In addition, although the electric vehicle driven with the motor used as a drive means is illustrated here as a vehicle, this invention is a vehicle driven with the engine (internal combustion engine) used as a drive means, the hybrid vehicle driven with an engine and a motor, etc. It can also be applied to other vehicles.

[Example 1]
FIG. 1 is a schematic configuration diagram showing a vehicle speed limiting device of this embodiment. FIG. 2 is a flowchart for explaining the control contents of the present embodiment implemented by the vehicle speed limiting device shown in FIG. FIG. 3 is a diagram for explaining control based on the flowchart shown in FIG.

  The vehicle 10 provided with the vehicle speed limiting device of the present embodiment is an electric vehicle, and a driving battery 11 in which electric power for driving the vehicle 10 is stored, and electric power supplied from the driving battery 11 is used as driving electric power. And a motor 13 that is rotationally driven by drive power supplied from the inverter 12 based on a required torque described later, and the rotational driving force of the motor 13 is a reduction gear, a drive The vehicle 10 is driven by being transmitted to the drive wheel 15 via the shaft.

  The driving wheel 15 of the vehicle 10 is provided with a wheel speed sensor 15a (vehicle speed detecting means) that detects the rotational speed of the driving wheel 15, and the steering wheel 16 also has a rotational speed of the steering wheel 16. Is provided with a wheel speed sensor 16a (vehicle speed detection means). The rotational speeds of the drive wheels 15 and the steering wheels 16 detected by the wheel speed sensors 15a and 16a are input to an ECU (Electronics Control Unit) 20 that is a control means, and are calculated as the vehicle speed of the vehicle 10 to be controlled later. As a result, the motor 13 is controlled.

  Further, the accelerator pedal 17 of the vehicle 10 is provided with an accelerator opening sensor 17a (accelerator opening detecting means) for detecting the accelerator opening (accelerator depression amount) of the accelerator pedal 17, and the accelerator opening sensor 17a. The opening degree of the accelerator pedal 17 detected in step S3 is input to the ECU 20 and is calculated as the accelerator depression amount of the driver, and the control described later is performed to control the motor 13. The required torque is calculated from the accelerator depression amount based on the accelerator opening sensor 17a and the vehicle speed based on the wheel speed sensors 15a and 16a.

  The vehicle speed limiting device of the present embodiment has a speed limiting function for performing control to set the required torque to 0 when the vehicle exceeds a preset limited vehicle speed, but the acceleration feeling until reaching the limited vehicle speed. At the same time, the following control is performed to ensure a sense of stability when traveling near the speed limit. Control performed in the present embodiment will be described below with reference to FIGS. 2 and 3 together with FIG.

(Step S1)
When the driver depresses the accelerator pedal 17, the ECU 20 detects the opening degree of the accelerator pedal 17 by the accelerator opening degree sensor 17a, calculates the accelerator depression amount of the driver, and proceeds to step S2.

(Step S2)
The ECU 20 detects the rotational speeds of the drive wheels 15 and the steering wheels 16 by means of the wheel speed sensors 15a and 16a, calculates the vehicle speed of the vehicle 10, determines whether or not a preset limit vehicle speed has been reached, and sets the limit vehicle speed. If it has not reached, the process proceeds to step S3, and if it has reached the limit vehicle speed, the process proceeds to step S4. In FIG. 3, the limit vehicle speed is set to 50 km / h as an example, but any vehicle speed can be set according to the application.

(Step S3)
When the vehicle speed of the vehicle 10 has not reached the limit vehicle speed, normal acceleration is performed, and the process returns to step S1. The normal acceleration is acceleration according to the required torque, and is acceleration with a vehicle speed restriction gain of 1 and no vehicle speed restriction (normal mode). In this way, until the vehicle speed reaches the limit vehicle speed, the gain is set to 1 in order to give a feeling of acceleration as much as possible.

(Step S4)
When the vehicle speed of the vehicle 10 reaches the limit vehicle speed after reaching the limit vehicle speed, the torque is limited based on the gain corresponding to the vehicle speed (limit mode). As the gain according to the vehicle speed, for example, as indicated by a dotted line in FIG. 3, the gain at the limit vehicle speed is 0, and the gain at the predetermined vehicle speed (<limit vehicle speed) defined in advance is 1. A negative gain gradient is used. Therefore, when the vehicle speed reaches the limit vehicle speed, the gain becomes 0, the output torque becomes 0, acceleration exceeding the limit vehicle speed is prohibited, and after reaching the limit vehicle speed, in order to avoid torque hunting, The required torque is limited by using the gain.

  Specifically, referring to FIG. 3, the gain is set to 1 until the limit vehicle speed reaches 50 km / h (see arrow P1), and the gain is changed from 1 to 0 when the limit vehicle speed reaches 50 km / h. (See arrow P2; gain gradient high) After reaching the limit vehicle speed of 50 km / h, when the vehicle speed increases between 40 km / h, which is the predetermined vehicle speed, and 50 km / h, which is the limit vehicle speed (limit speed range), The gain is reduced from 1 to 0 (see arrow P3; gain gradient is small).

  Therefore, since the gain is set to 1 until the limit vehicle speed reaches 50 km / h, a large acceleration feeling can be obtained until the limit vehicle speed is reached, and when the limit vehicle speed is reached, the gain is changed from 1 to 0. After the above acceleration is prohibited and the limit vehicle speed is reached, the torque is limited based on the gain corresponding to the vehicle speed. Therefore, when reaccelerating within the limited speed range, the torque is limited according to the vehicle speed. Therefore, it is possible to obtain a feeling of acceleration near the lower limit of the speed limit range, and to avoid torque hunting near the upper limit of the speed limit range, that is, near the limit vehicle speed, to ensure a sense of stability during driving. Can do.

(Step S5)
Whether the vehicle speed is equal to or lower than the predetermined vehicle speed is checked. If the vehicle speed exceeds the predetermined vehicle speed, the process returns to step S4. If the vehicle speed is equal to or lower than the predetermined vehicle speed, the process proceeds to step S6. In other words, the torque limit according to the vehicle speed continues until the vehicle speed becomes a predetermined vehicle speed or less. The predetermined vehicle speed is the lower limit of the speed limit range, and in FIG. 3, as an example, the predetermined vehicle speed is 40 km / h. However, any vehicle speed can be set according to the application. Also, an arbitrary gradient can be set for the gain gradient according to the application.

(Step S6)
When the vehicle speed becomes equal to or lower than the predetermined vehicle speed, the torque limitation is canceled and the process returns to step S1 (reset means). That is, based on a predetermined condition that the vehicle speed is equal to or lower than the predetermined vehicle speed, the restriction mode is reset and the normal mode is restored to enable normal (gain = 1) acceleration.

  By the above-described control, the trade-off relationship between the acceleration feeling and the stability feeling during traveling is eliminated, and it is possible to ensure the feeling of stability during traveling near the limit vehicle speed as well as the acceleration feeling until reaching the limit vehicle speed.

[Example 2]
The present embodiment is another example of the control performed by the vehicle speed limiting device shown in FIG. Although the description of FIG. 1 that overlaps with the first embodiment is omitted here, the control of the present embodiment will be described with reference to FIG. 1 and with reference to FIGS. 4 and 5. Here, FIG. 4 is a flowchart for explaining the control contents of the present embodiment implemented by the vehicle speed limiting device shown in FIG. FIG. 5 is a diagram for explaining control based on the flowchart shown in FIG.

  The vehicle speed limiting device of the present embodiment also has a speed limiting function for performing control to set the required torque to 0 when the vehicle exceeds a preset vehicle speed limit. In the control of the vehicle speed limiting device shown in the first embodiment, it is possible to ensure a sense of stability when traveling near the limited vehicle speed as well as the acceleration feeling until reaching the limited vehicle speed. Since the acceleration is limited mode until the vehicle speed falls below the predetermined vehicle speed, the acceleration in normal mode until reaching the limited vehicle speed and acceleration in the limited mode after reaching the limited vehicle speed Will be different.

  For example, referring to FIG. 3 described above, when accelerating in the normal mode, the gain is 1, and the acceleration is performed according to the required torque (see arrow P1). However, when accelerating in the limit mode (reacceleration), According to the gain gradient indicated by the dotted line, acceleration is performed using the required torque multiplied by the gain according to the vehicle speed (see arrow P4), and the feeling of acceleration is different.

  Therefore, in this embodiment, in the limit mode after reaching the limit vehicle speed, if the predetermined condition is satisfied before the speed becomes equal to or lower than the predetermined speed, the limit mode is reset and returned to the normal mode. Control performed in the present embodiment will be described below with reference to FIGS. 4 and 5 together with FIG.

(Step S11)
When the driver depresses the accelerator pedal 17, the ECU 20 detects the opening of the accelerator pedal 17 by the accelerator opening sensor 17a, calculates the amount of accelerator depression, and proceeds to step S12.

(Step S12)
The ECU 20 detects the rotational speeds of the drive wheels 15 and the steering wheels 16 by means of the wheel speed sensors 15a and 16a, calculates the vehicle speed of the vehicle 10, determines whether or not a preset limit vehicle speed has been reached, and sets the limit vehicle speed. When it has not reached, it progresses to step S13, and when it reaches | attains the limit vehicle speed, it progresses to step S14. In FIG. 5, the limit vehicle speed is set to 50 km / h as an example, but any vehicle speed can be set according to the application.

(Step S13)
When the vehicle speed of the vehicle 10 has not reached the limit vehicle speed, normal acceleration is performed and the process returns to step S11. The normal acceleration is acceleration according to the required torque, and is acceleration with a vehicle speed restriction gain of 1 and no vehicle speed restriction (normal mode). In this way, until the vehicle speed reaches the limit vehicle speed, the gain is set to 1 in order to give a feeling of acceleration as much as possible.

(Step S14)
When the vehicle speed of the vehicle 10 reaches the limit vehicle speed after reaching the limit vehicle speed, the torque is limited based on the gain corresponding to the vehicle speed (limit mode). As the gain according to the vehicle speed, for example, as indicated by a dotted line in FIG. 5, the gain at the limit vehicle speed is 0, and the gain at the predetermined vehicle speed (<limit vehicle speed) defined in advance is 1 A negative gain gradient is used. Therefore, when the vehicle speed reaches the limit vehicle speed, the gain becomes 0, the output torque becomes 0, acceleration exceeding the limit vehicle speed is prohibited, and after reaching the limit vehicle speed, in order to avoid torque hunting, The required torque is limited by using the gain.

  Specifically, referring to FIG. 5, the gain is set to 1 until the limit vehicle speed reaches 50 km / h (see arrow P1), and when the limit vehicle speed reaches 50 km / h, the gain is changed from 1 to 0. (See arrow P2; gain gradient high) After reaching the limit vehicle speed of 50 km / h, when the vehicle speed increases between 40 km / h, which is the predetermined vehicle speed, and 50 km / h, which is the limit vehicle speed (limit speed range), The gain is reduced from 1 to 0 (see arrow P3; gain gradient is small).

  Therefore, since the gain is set to 1 until the limit vehicle speed reaches 50 km / h, a large acceleration feeling can be obtained until the limit vehicle speed is reached, and when the limit vehicle speed is reached, the gain is changed from 1 to 0. After the above acceleration is prohibited and the limit vehicle speed is reached, the torque is limited based on the gain corresponding to the vehicle speed. Therefore, when reaccelerating within the limited speed range, the torque is limited according to the vehicle speed. Therefore, it is possible to obtain a feeling of acceleration near the lower limit of the speed limit range, and to avoid torque hunting near the upper limit of the speed limit range, that is, near the limit vehicle speed, to ensure a sense of stability during driving. Can do.

(Step S15)
It is checked whether or not the amount of depression of the accelerator pedal 17 is equal to or less than a predetermined value. If it exceeds the predetermined value, the process proceeds to step S16. Here, as described above, the accelerator depression amount may be calculated based on the accelerator opening sensor 17a, and it may be confirmed whether the calculated accelerator depression amount is equal to or less than a predetermined value.

  Here, “below a certain value” is an arbitrary value for determining that the driver does not intend to accelerate. When the depression of the accelerator pedal 17 is loosened and the accelerator depression amount is less than or equal to a predetermined value, the torque limit described later is released under the condition of “a certain value or less”. As the “constant value”, for example, an accelerator depression amount at which the required torque becomes 0 or less may be set. When the accelerator depression amount (accelerator opening) = 0 is set as the “constant value”, the condition “less than a certain value” is satisfied only when the accelerator pedal 17 is not depressed, that is, when the accelerator is off. Therefore, the torque limitation, which will be described later, is released.

(Step S16)
If the amount of depression of the accelerator pedal 17 exceeds a certain value, it is checked whether the vehicle moves forward and the required torque is 0 or less. If the vehicle moves forward and the required torque is 0 or less, step S17 is performed. If the vehicle is not moving forward or the required torque is not 0 or less, that is, if the vehicle stops or reverses, or the required torque is greater than 0, the process returns to step S14. Here, the traveling direction of the vehicle is confirmed based on the vehicle speed based on the wheel speed sensors 15a and 16a, and the requested torque obtained from the vehicle speed based on the wheel speed sensors 15a and 16a and the accelerator depression amount based on the accelerator opening sensor 17a, What is necessary is just to confirm the magnitude | size.

  Here, “the vehicle is moving forward and the required torque is 0 or less” is a condition for determining that the driver does not intend to accelerate even when the amount of depression of the accelerator pedal 17 exceeds a certain value. . For example, when the depression of the accelerator pedal 17 is loosened, the condition may be met, and in this case, the torque limitation described later is released. Further, in the vehicle 10 that is an electric vehicle, when the brake pedal is depressed and regeneration to the drive battery 11 is performed, this condition is satisfied, and in this case as well, the torque limitation described later is released. It will be.

(Step S17)
When the depression amount of the accelerator pedal 17 is equal to or less than a certain value, or when the vehicle moves forward and the required torque is 0 or less, the torque limitation is canceled and the process returns to step S11 (reset means). That is, based on a predetermined condition that the amount of depression of the accelerator pedal 17 is a predetermined value or less, or a predetermined condition that the vehicle is moving forward and the required torque is 0 or less, the limit mode is reset and returned to the normal mode. Normal (gain = 1) acceleration is possible.

  Specifically, with reference to FIG. 5, after reaching the limit vehicle speed of 50 km / h, the request according to the vehicle speed is applied according to the gain gradient indicated by the dotted line until the limit mode is reset. Torque is used to accelerate (re-accelerate) (see arrow P4), but when the above condition is satisfied in the speed change range, the limit mode is reset and returned to the normal mode (see arrow R). (Gain = 1) acceleration (re-acceleration) is possible.

  Even in this embodiment, if the restriction mode is not reset, the torque restriction according to the vehicle speed continues until the vehicle speed becomes equal to or lower than the predetermined vehicle speed, as in the first embodiment. Since the condition for resetting the restriction mode (the condition of step S15 or 16) is satisfied, the torque restriction corresponding to the vehicle speed continues until these conditions are satisfied. When the above condition is satisfied, the limit mode is reset and the normal mode is restored. Therefore, when the vehicle is to be accelerated again after reaching the limit vehicle speed, if the above condition is satisfied, normal acceleration is performed. When resetting the limit mode and returning to the normal mode, if the torque fluctuation at that time is greater than the permissible fluctuation value specified in advance, control is made so that the torque fluctuates gently when returning to the normal mode. Also good.

  By the above-described control, the trade-off relationship between the acceleration feeling and the stability feeling during traveling is eliminated, and it is possible to ensure the feeling of stability during traveling near the limit vehicle speed as well as the acceleration feeling until reaching the limit vehicle speed. In addition, even after reaching the limit vehicle speed, when a predetermined condition is satisfied, normal acceleration can be performed, and a certain acceleration feeling can be obtained.

  In this embodiment, as a gain according to the vehicle speed in the restriction mode, a linear negative gain in which the gain at the restriction vehicle speed is 0 and the gain at the predetermined vehicle speed (<restriction vehicle speed) defined in advance is 1. Although one having a gradient is shown, the gain is not limited to one having a linear gradient. For example, it may be a gain setting that decreases in a curve from gain 1 at a predetermined vehicle speed to gain 0 at a limited vehicle speed. Further, the gain gradient may be changed between gain 1 at a predetermined vehicle speed and gain 0 at a limited vehicle speed. In this way, the gain can be set according to the application.

  The present invention can be applied to any vehicle as long as it has a speed limiting function.

DESCRIPTION OF SYMBOLS 10 Vehicle 11 Drive battery 12 Inverter 13 Motor 15 Drive wheel 15a Wheel speed sensor (vehicle speed detection means)
16 Steering wheel 16a Wheel speed sensor (vehicle speed detection means)
17 accelerator pedal 17a accelerator opening sensor (accelerator opening detecting means)
20 ECU (control means)

Claims (7)

Vehicle speed detecting means for detecting the vehicle speed of the vehicle;
An accelerator opening detecting means for detecting an accelerator opening of the accelerator pedal of the vehicle;
Control means for controlling the driving means of the vehicle based on the required speed calculated based on the vehicle speed and the accelerator opening;
The control means sets the required torque to 0 when the vehicle exceeds a preset limit vehicle speed, and when the vehicle reaches the limit vehicle speed and falls below the limit vehicle speed, A vehicle speed limiting device that limits the required torque in a limiting mode that limits the required torque based on a gain that decreases in response. The vehicle speed limiting device according to claim 1,
The control means releases the restriction mode based on a predetermined condition when the restriction mode is being implemented. The vehicle speed limiting device according to claim 2,
The vehicle speed limiting device according to claim 1, wherein the predetermined condition is that the vehicle speed is equal to or lower than a predetermined vehicle speed smaller than the limited vehicle speed. The vehicle speed limiting device according to claim 2,
The vehicle speed limiting device according to claim 1, wherein the predetermined condition is that the accelerator opening is equal to or less than a predetermined value. The vehicle speed limiting device according to claim 4,
The vehicle speed limiting device characterized in that the fixed value is the accelerator opening at which the required torque is 0 or less. The vehicle speed limiting device according to claim 4,
A vehicle speed limiting device, wherein the constant value is set to zero. The vehicle speed limiting device according to claim 2,
The vehicle speed limiting device according to claim 1, wherein the predetermined condition is that the vehicle moves forward and the required torque is 0 or less.

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