JP2000006683A - Traveling speed control system for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the cruising distance by reducing the target speed to continue the traveling at a constant speed when the traveling speed drops by a specified value during the traveling at a constant speed. SOLUTION: When a motor 1 for traveling of an electric car is overheated, the temperature is detected by a motor temperature detection part 11, and the torque limit value is outputted from a torque limit part 8. Also when the residual capacity of a battery detected by a battery residual capacity detection part 10 is small, the torque limit value is outputted from an output limit part 7. An output torque switching part 9 outputs the torque command value outputted from a constant speed traveling control part 6 or the torque limit value, whichever is the smaller, to a motor controller 3. The constant speed traveling control part 6 reduces the target speed and continues the traveling at the constant speed when the output torque is limited by the output torque switching part 9, and the traveling speed drops by the specified value, and the traveling at the specified speed is effected at the traveling speed to suppress the overheat, or at the traveling speed to efficiently use the residual capacity of the battery.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a traveling speed control system for a vehicle capable of controlling the traveling speed of a vehicle at a set speed at a constant speed.

[0002]

2. Description of the Related Art In recent years, vehicles equipped with a traveling speed control system capable of controlling a vehicle at a constant speed at a speed set by a driver are increasing. With the electronic control of the vehicle control unit, a vehicle control unit of the vehicle controller in which the control unit of the traveling speed control system is built is also under development. As the traveling speed control system, for example, in a gasoline engine vehicle, a vehicle speed measured by a vehicle speed sensor is compared with a set speed set by a driver, a throttle valve opening of the engine is controlled, and a constant speed traveling can be performed. Is known.
In electric vehicles, to keep the set speed constant,
The output torque of the traveling motor is controlled.

[0003] If constant-speed running is set, there is no need to continue to depress the accelerator pedal, so that the burden on the driver is reduced, especially when traveling a long distance on an expressway. In general, the vehicle speed at the time when the constant-speed traveling switch is pressed is stored as the set speed, the constant-speed traveling is performed, and when the constant-speed traveling switch is turned off or when the brake pedal is depressed, The constant speed running is canceled. Further, in these traveling speed control systems, even when the vehicle speed temporarily decreases, if the vehicle speed is within a predetermined undercut vehicle speed lower than the predetermined speed by a predetermined speed, the constant speed traveling state is maintained, and the vehicle travels at the predetermined speed. Is controlled to be performed.

[0004]

However, for example, in an electric vehicle, in order to protect the battery, when the remaining battery capacity becomes small, the output of the battery output is limited. When the temperature of the traveling motor rises above a predetermined temperature, the output torque is limited to protect the motor. For this reason, when the output is limited or the torque is limited while the vehicle is traveling at a constant speed, it is impossible to output the output torque required to maintain the set speed, and the vehicle speed is reduced. When the vehicle speed falls below the undercut vehicle speed, the constant speed traveling is canceled.

[0005] As described above, if the set speed is reduced to some extent and the vehicle is driven at a vehicle speed at which the output torque is sufficient, the constant speed traveling is canceled even if the constant speed traveling is possible. In particular, when the remaining battery capacity is reduced and the output of the battery output is limited, in order to efficiently use the remaining battery capacity, it is desirable to continue the constant speed traveling at a set speed at which traveling is possible. .

Therefore, according to the present invention, even when the traveling vehicle speed decreases by a predetermined value or more during the constant speed traveling, the constant speed traveling is not canceled without releasing the traveling speed.
It is an object of the present invention to provide a vehicle traveling speed control system capable of resetting a traveling vehicle speed as a new constant traveling speed, maintaining a constant traveling state, and improving a cruising distance.

[0007]

Therefore, in the present invention,
A vehicle speed sensor for detecting a traveling speed of the vehicle, a manual setting unit for setting a speed at which the vehicle is driven at a constant speed by manual operation, and a constant speed traveling control unit for causing the vehicle to travel at a constant speed at the set constant speed. When the traveling speed detected by the vehicle speed sensor is lower than the manually set speed set by the manual setting unit by a predetermined value or more and is lower than the constant speed traveling speed set by the constant speed traveling control unit, Comprises a constant speed traveling speed changing means for resetting the traveling vehicle speed as a new constant speed traveling speed, and the initial value of the constant speed traveling speed is a manually set speed.

A vehicle speed sensor for detecting a running speed of the vehicle;
A manual setting section for setting the speed at which the vehicle travels at a constant speed by manual operation; and a constant speed traveling for outputting a torque command value for controlling the output torque of the traveling motor in order to perform the constant speed traveling at the set constant speed traveling speed. A control unit, a vehicle state detection unit that detects a vehicle state, and an output torque control unit that limits an output torque upper limit based on the vehicle state detected by the vehicle state detection unit. The output torque is limited by the output torque control unit, and the traveling vehicle speed detected by the vehicle speed sensor is lower than the manually set speed set by the manual setting unit by a predetermined amount or more, and further, the constant speed set by the constant speed travel control unit. If the traveling speed is lower than the traveling speed, a constant traveling speed changing means for resetting the traveling vehicle speed as a new constant traveling speed may be provided, and the initial value of the constant traveling speed may be a manually set speed.

It is preferable that the vehicle state detecting section has a motor temperature detecting section for detecting a temperature of the traveling motor. Further, the vehicle state detection unit may include a drive circuit temperature detection unit that detects a temperature of a drive circuit of the traveling motor. The vehicle state detector may include a battery temperature detector that detects the temperature of the battery.

The vehicle state detecting section has a battery remaining capacity detecting section for detecting the capacity of a battery for supplying electric power to the traveling motor, and the output torque controlling section uses a detection result of the battery remaining capacity detecting section and a vehicle speed sensor. The output torque may be controlled based on the detected traveling vehicle speed.

[0011]

By providing a constant speed traveling speed change means in the constant speed traveling control unit for performing normal constant speed traveling, the traveling vehicle speed is set at a manually set speed during traveling at a constant speed. Even if the vehicle speed falls below the undercut vehicle speed, which is the lower limit speed at which the vehicle returns to the constant speed traveling state, the traveling vehicle speed is automatically reset as a new constant speed traveling speed, which is different from the initially manually set speed. , Maintain constant speed driving. While repeating this automatic setting, if the traveling vehicle speed is lower than the undercut vehicle speed by performing resetting, if the traveling vehicle speed is lower than the currently set constant traveling speed The slowest traveling vehicle speed is set and fixed as the vehicle speed at which the vehicle travels at a constant speed.

In an electric vehicle, for example, when the temperature of a running motor, a motor drive circuit, or a battery serving as a power source of the running motor rises by a predetermined amount or more, the output torque is limited for safety. When the remaining capacity of the battery falls below a predetermined amount, the output of the battery is limited.
Even if the vehicle is traveling at a constant speed, if the traveling vehicle speed falls below the undercut vehicle speed due to these restrictions, the slowest traveling vehicle speed after the traveling vehicle speed falls below the undercut vehicle speed is determined. Re-set the speed as the vehicle traveling at a constant speed. Therefore, the vehicle speed at which the vehicle can travel at a constant speed while suppressing the temperature rise of the motor or the like, or the vehicle speed at which the vehicle can maintain the constant speed traveling even with a small remaining capacity of the battery is reset as the constant speed traveling vehicle speed. Is performed.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described with reference to examples. FIG. 1 is a block diagram showing the configuration of the embodiment. The motor 1 is a running motor mounted on an electric vehicle, and is an AC induction motor. A transaxle (not shown) is connected to the motor 1, and the driving force from the transaxle is transmitted to both front wheels (not shown) via left and right front wheel shafts. The motor 1 is connected to a traveling speed control unit 4 via an insulated gate bipolar transistor (hereinafter referred to as IGBT) 2 and a motor controller 3. Motor 1
Are connected via an IGBT 2 to a battery 5 which is a main power source for driving the vehicle.

The traveling speed control unit 4 includes a constant speed traveling control unit 6 for calculating a torque command value when performing a constant speed traveling, an output limiting unit 7 for calculating a torque limiting value according to the state of the vehicle, and a torque limiting unit. It comprises a unit 8 and an output torque switching unit 9 that outputs a torque command value or a torque limit value to the motor controller 3. The output limiter 7 is connected to a remaining battery charge detector 10 for detecting the remaining charge of the battery and a vehicle speed sensor 15 for detecting the traveling vehicle speed from the rotation of wheels driven by the motor 1. The torque limiter 8 includes a motor temperature detector 11 disposed near the motor 1 for detecting the temperature of the motor 1 and an IGBT for detecting the temperature of the IGBT 2
A temperature detection unit 12 and a battery temperature detection unit 13 that detects the temperature of the battery are connected.

The cruise control unit 6 includes a vehicle speed sensor 15,
A shift position detector 16 for detecting a traveling range from a position of a shift lever, a constant speed traveling switch 17 provided near a driver's seat for constant speed traveling, and a brake switch 1
8 are connected. The brake switch 18 is attached to a brake pedal (not shown) and is turned on at a minute stroke at the start of depression of the brake pedal. The output limiting unit 7, the torque limiting unit 8, and the output torque switching unit 9 constitute an output torque control unit according to the present invention. The constant speed switch 17 constitutes a manual setting unit of the invention, and the IGBT temperature detection unit 12 constitutes a drive circuit temperature detection unit.

Next, the operation at the time of running at a constant speed will be described.
First, the driver operates the shift lever before actually performing the constant speed traveling to set the drive range. When the vehicle speed reaches a desired value, the constant-speed traveling switch 17 is turned on. When the constant-speed traveling switch 17 is turned on, the constant-speed traveling control unit 6 first determines that the shift position detected by the shift position detecting unit 16 is the drive range, and the vehicle speed sensor 15
It is determined whether or not the traveling vehicle speed detected in is in the range of 40 km / h to 110 km / h and the brake switch 18 is in the off state, and if these conditions are satisfied,
Shift to the constant speed running state.

When the vehicle shifts to the constant speed traveling state, the traveling vehicle speed when the constant speed traveling switch 17 is turned on is set as the constant traveling speed, and the traveling vehicle speed newly input from the vehicle speed sensor 15 is set every 96 ms. The calculated constant speed traveling speed is compared, a torque command value necessary for traveling at the constant speed traveling speed is calculated, and output to the output torque switching unit 9. When the traveling vehicle speed decreases to 40 km / h or less, the constant speed traveling state is released. In addition, in parallel with the above-described torque command value calculation, the constant-speed traveling control unit 6 restricts the output torque even when the driver selects the constant-speed traveling, and reduces the vehicle speed. It has a function to change the set speed.
Details regarding this function will be described later.

The battery remaining capacity detecting unit 10 constantly monitors the remaining capacity of the battery 5 and outputs the detection result to the output limiting unit 7. When the remaining battery capacity becomes equal to or less than a predetermined amount, the output limiting unit 7 calculates an output limit value for effectively using the remaining battery capacity. Next, a motor rotation speed N (rpm) is obtained from the traveling vehicle speed detected by the vehicle speed sensor 15, and a torque limit value is calculated from the following equation. The output P (kW), torque T (kgf · m), and constant A were used. P = TNN / A The obtained torque limit value is output to the output torque switching unit 9.

Similarly, the motor temperature detector 11, the IGBT
Similarly, the temperature detector 12 and the battery temperature detector 13 constantly monitor the temperature, and output the detection result to the torque limiter 8. When the temperature detected by the detecting unit exceeds a predetermined temperature, the torque limiting unit 8 calculates a torque limiting value required to suppress a temperature rise, and outputs the torque limiting value to the output torque switching unit 9.

The output torque switching section 9 monitors the outputs from the output limiting section 7 and the torque limiting section 8, and when the output is not limited, outputs the torque command value output from the constant speed traveling control section 6. It is output to the motor controller 3 as it is. When a limit value is input from the output limiter 7 or the torque limiter 8, the input torque limit value is compared with the torque command value, and the smallest value is output to the motor controller 3. When the torque is restricted, the torque restriction value is also output to the constant-speed traveling control unit 6. Therefore, even if the driver selects constant-speed traveling, if the remaining capacity of the battery 5 is small or if the temperature of the motor 1 or the like is rising, the torque calculated by the constant-speed traveling control unit 6 Since the torque limit value is output instead of the command value,
The vehicle speed decreases.

Next, the operation for changing the set speed performed by the constant speed traveling control unit 6 when the vehicle speed is reduced due to the torque limitation will be described with reference to the flowchart shown in FIG. In step 101, it is first determined whether the vehicle is traveling at a constant speed. If the vehicle is traveling at a constant speed, the process proceeds to step 102. If the vehicle is not traveling at a constant speed, the process proceeds to step end. This step is performed at predetermined time intervals. Step 10
In 2, it is determined whether or not a torque limit is applied and a torque limit value is input from the output limiter 7 or the torque limiter 8. If the torque limit value has not been input, the process proceeds to step end. If input, step 103
Proceed to.

In step 103, it is determined whether the calculated torque command value is larger than the torque limit value. If the torque command value is not larger than the torque limit value, the process proceeds to step end. If it is larger than the torque limit value, step 1
Go to 04. In step 104, the constant speed traveling switch 1
The undercut vehicle speed 10 km / h lower than the manually set speed manually set as the speed at which the vehicle travels at a constant speed is compared with the traveling vehicle speed detected by the vehicle speed sensor 15. If the traveling vehicle speed is lower than the undercut vehicle speed, , Step 10
Go to 5. If not, go to step end.

In step 105, it is determined whether or not the traveling vehicle speed is lower than the constant traveling vehicle speed currently set in the constant traveling controller 6. When the traveling vehicle speed is lower than the constant traveling vehicle speed, the process proceeds to step 106. If not, go to step end. The constant speed traveling vehicle speed is a manually set speed when the constant speed traveling switch 17 is turned on. Thereafter, the torque is limited, and the operation described in this flowchart is performed up to step 106. If the operation is reset, the set speed value is obtained in the next flow. In step 106, the traveling vehicle speed is set as the constant traveling speed.

With the above operation, when the torque is limited and the traveling vehicle speed falls below the undercut vehicle speed, the constant traveling speed is automatically changed. The undercut vehicle speed is set and fixed in accordance with the manually set speed initially set by the constant speed switch.
Steps 101 to 106 of the flowchart shown in FIG. 2 constitute the constant speed traveling speed changing means of the present invention.

Next, referring to FIG. 3 and FIG.
An operation example when the motor is overheated and the torque is limited will be described. FIG. 3A shows the relationship between the torque limit value and the output of the output torque switching unit, and FIG. 3B shows the relationship between the set speed set as the speed at which the vehicle travels at a constant speed and the traveling vehicle speed. At time a1, the motor 1 is overheated, the temperature rise is detected by the motor temperature detector 11, and the torque limiter 8 outputs the torque limit value. Time a1 when the torque limit value is larger than the torque command value
From time to time a2, the torque command value is output from the output torque switching unit 9 to the motor controller 3 in the same manner as in the normal constant speed traveling state, and the traveling vehicle speed is set to 70 km / h manually set by the constant speed traveling switch 17. Keep.

At time a2, the temperature of the motor 1 further rises, the torque limit value falls, and becomes smaller than the torque command value. The output from the output torque switching unit 9 switches to the torque limit value, and the traveling vehicle speed decreases. However, before the traveling vehicle speed decreases to 60 km / h, which is the undercut vehicle speed, the temperature of the motor 1 decreases, and at time a3, the torque limit value starts increasing, so that steps 104 to 105 in the flowchart shown in FIG. The constant traveling speed is maintained at the manually set speed initially set manually by the driver. At time a4, since the torque limit value has become larger than the torque command value, the output of the output torque switching unit 6 also returns to the torque command value for normal constant-speed running, and the traveling vehicle speed also increases to the manually set speed. Will be maintained.

Next, the operation for automatically changing the set speed will be described with reference to FIG. As in FIG. 3, (a)
Indicates the relationship between the torque limit value and the output of the output torque switching unit,
(B) shows the relationship between the set speed and the traveling vehicle speed. At time b1, the torque limit is applied. At time b2, the torque limit value becomes smaller than the torque command value, the output of the output torque switching unit 9 becomes the torque limit value, and the traveling vehicle speed also decreases. Time b3
When the traveling vehicle speed becomes equal to or less than the undercut vehicle speed of 60 km / h, the process proceeds from step 104 to step 105 in the flowchart. In step 105, since the traveling vehicle speed is smaller than the constant speed traveling speed, the process proceeds to step 106.
The traveling vehicle speed is set as the constant traveling speed. Since the torque limit value continues to decrease from time b3 to time b4, steps 101 to 106 are repeated, and the constant speed traveling speed also decreases.
m / h.

After the time point b4, as a result of the decrease in the traveling vehicle speed, the temperature of the motor 1 decreases, the torque limitation is eased, and the torque limit value increases. The constant speed is 55km
/ H. Therefore, the process proceeds from step 103 of the flowchart to the step end, and the set speed is not changed. The set speed is fixed to the traveling vehicle speed of 55 km / h at the time b4, and the constant speed traveling control unit 6 outputs a torque command value for performing the 55 km / h constant speed traveling to maintain the constant speed traveling. .

As described above, even in the constant-speed running state, the motor 1, the IGBT 2 or the battery 5 is overheated, and the torque control unit 8 outputs a torque limit value or the remaining battery capacity decreases, and the output limit unit 7, the output torque is limited by the output torque switching unit 9, and even when the traveling vehicle speed falls below the undercut vehicle speed, the constant speed traveling is not automatically canceled, and the traveling vehicle speed becomes under. The slowest traveling vehicle speed after the vehicle speed has dropped below the cut vehicle speed is reset as the constant traveling vehicle speed.

Therefore, when the remaining capacity of the battery decreases and the output is limited and the traveling vehicle speed decreases, the target vehicle speed is reduced and the vehicle continues to run at a constant speed, so that the remaining capacity of the battery can be used efficiently. The cruising distance can be improved. Similarly, when the traveling vehicle speed decreases due to the torque limitation performed due to the temperature rise of the motor and the like,
Since the target vehicle speed is reduced and the cruising is continued, the cruising can be continued at the speed at which the vehicle can travel while suppressing the temperature rise, and the cruising can be performed even if the vehicle condition is not completely good. It is possible to improve the convenience when performing long-distance driving. In addition, the driver can grasp the vehicle state such as whether the overheating state of the motor is minor or severe, based on the decrease in the speed at which the vehicle travels at a constant speed. improves.

In the present embodiment, the speed reduced by 10 km / h from the speed at which the vehicle travels at a constant speed is set as the undercut vehicle speed. However, the present invention is not limited to this. The driver may notice a noticeable decrease in the vehicle speed. It is sufficient if there is no decrease width, and it is a constant width or a fixed ratio according to the vehicle speed, for example, 10
%, The undercut vehicle speed can be set to 81 km / h when the speed is 90 km / h, and the undercut vehicle speed can be set to 54 km / h when the speed is 60 km / h.

[0032]

As described above, in the constant speed traveling control system for a vehicle according to the present invention, the constant speed traveling control unit for performing normal constant speed traveling is provided with the constant speed traveling speed changing means. Even if the traveling vehicle speed drops by more than a predetermined value, the traveling speed is not reset, and the traveling vehicle speed is automatically reset as a new constant traveling speed. Is maintained, and convenience when performing a long-distance drive is improved. During this automatic resetting, if the traveling vehicle speed is lower than the constant speed traveling speed set in the constant speed control unit, the resetting is performed. Therefore, the slowest traveling vehicle speed after the traveling vehicle speed has decreased by a predetermined value or more is set as the constant speed traveling vehicle speed, and the constant speed traveling is maintained, so that a stable constant speed traveling state is obtained.

In an electric vehicle, for example, when the running vehicle speed decreases by a predetermined amount or more because the remaining battery capacity is reduced and the battery output is limited, the target speed is reduced and the constant speed running is continued. The remaining capacity of the battery can be used efficiently, and the cruising distance is improved. Similarly, in the case where the torque is limited due to the temperature rise of the motor and the like, and the traveling vehicle speed decreases, the target vehicle speed is similarly reduced to continue the constant speed traveling. Since the constant speed traveling can be continued, the vehicle can be driven at a constant speed even if the vehicle state is not completely good, and the convenience when performing a long distance drive is improved. In addition, the driver can grasp the vehicle state from the decrease in the speed at which the vehicle travels at a constant speed, thereby improving the safety of traveling the vehicle.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of an embodiment of the present invention.

FIG. 2 is a flowchart illustrating an operation in the embodiment.

FIG. 3 is a diagram illustrating an operation when torque limitation is performed.

FIG. 4 is a diagram illustrating an operation when a torque limit is performed.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 motor 2 IGBT 3 motor controller 4 traveling speed control unit 5 battery 6 constant speed traveling control unit 7 output control unit 8 torque limiting unit 9 output torque switching unit 10 battery remaining capacity detection unit 11 motor temperature detection unit 12 IGBT temperature detection unit 13 Battery temperature detector 15 Vehicle speed sensor 16 Shift position detector 17 Constant speed travel switch 18 Brake switch

Claims (6)

[Claims] A vehicle speed sensor for detecting a traveling vehicle speed of the vehicle;
A manual setting unit that sets a speed at which the vehicle travels at a constant speed by manual operation; and a constant speed travel control unit that causes the vehicle to travel at a constant speed at the set constant speed travel speed. The constant speed travel control unit includes a vehicle speed sensor. If the traveling vehicle speed detected in the step (1) is lower than the manual setting speed set by the manual setting unit by a predetermined amount or more and is lower than the constant speed traveling speed set in the constant speed traveling control unit, the traveling vehicle speed is changed to the new constant speed. A traveling speed control system for a vehicle, comprising a constant traveling speed changing means for resetting the traveling speed as an initial value, wherein an initial value of the constant traveling speed is the manually set speed. A vehicle speed sensor for detecting a traveling vehicle speed of the vehicle;
A manual setting section for setting the speed at which the vehicle travels at a constant speed by manual operation; and a constant speed traveling for outputting a torque command value for controlling the output torque of the traveling motor in order to perform the constant speed traveling at the set constant speed traveling speed. A control unit, a vehicle state detection unit that detects a vehicle state, and an output torque control unit that limits an output torque upper limit value based on the vehicle state detected by the vehicle state detection unit; The output torque is limited by the output torque control unit, and the traveling vehicle speed detected by the vehicle speed sensor is lower than a manually set speed set by the manual setting unit by a predetermined amount or more, and further, is set in the constant speed travel control unit. A constant speed traveling speed changing means for resetting the traveling vehicle speed as a new constant speed traveling speed when the traveling speed is lower than the constant traveling speed, wherein an initial value of the constant speed traveling speed is the manually set speed. To Running speed control system for a vehicle according to symptoms. 3. The vehicle running speed control system according to claim 2, wherein said vehicle state detecting section includes a motor temperature detecting section for detecting a temperature of a running motor. 4. The running speed control system for a vehicle according to claim 2, wherein said vehicle state detecting section includes a driving circuit temperature detecting section for detecting a temperature of a driving circuit of a driving motor. 5. The vehicle running speed control system according to claim 2, wherein said vehicle state detecting section has a battery temperature detecting section for detecting a temperature of a battery. 6. The vehicle state detecting section has a remaining battery level detecting section for detecting a capacity of a battery for supplying electric power to a traveling motor, and the output torque controlling section includes a detection result of the remaining battery level detecting section. 6. The vehicle running speed control system according to claim 2, wherein the output torque is controlled based on the vehicle speed detected by the vehicle speed sensor.