JP2000278815A - Creep controller for electric vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve creep running feeling in an electric vehicle. SOLUTION: When a vehicle stopping condition is detected by a vehicle stopping detection means 21 and the depressing release of a brake pedal 12 is detected by a depressing sensor 13, a creep control means 16 controls the output from a motor 1 so that the vehicle may be preset creep speed and increases the output from the motor 1 until the preset creep speed is reached independently of the vehicle condition, therefore the vehicle can attain stable starting without moving backward at the uphill starting and excellent response and stable creep running even if running resistance changes, thereby improving creep running feeling in an electric vehicle.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a creep control device for controlling a creep running of an electric vehicle which obtains a driving force by a motor.

[0002]

2. Description of the Related Art In order to improve exhaust gas performance, improve fuel efficiency, reduce noise, and the like, various electric vehicles that obtain a driving force by a motor have been developed. Since the production efficiency of the electric power of the motor is lower than the production efficiency of the fuel of the internal combustion engine (engine), various hybrid electric vehicles that obtain driving force by the engine and the motor have been developed and put to practical use in order to supplement the production efficiency of the electric power. ing. 2. Description of the Related Art As a hybrid electric vehicle, there is known a type in which a driving force is obtained by a motor and electric power serving as a power source of the motor is generated by an engine. There is also known an apparatus that obtains driving force by using a motor and an engine together. In an electric vehicle including a hybrid electric vehicle, the output of a motor is controlled in accordance with the operation state of an accelerator pedal and a brake pedal, thereby ensuring the same driving operability as a normal vehicle.

In an electric vehicle, a creep force for creep traveling is also generated by a motor.
Conventional creep control devices for electric vehicles, for example, as disclosed in Japanese Patent No. 2674258 and the like, when the traveling speed becomes substantially zero, the operation state of the accelerator pedal and the brake pedal, the inclination of the road surface , A constant torque is generated by the motor to obtain a creep force for creep running.

[0004]

The conventional creep control device controls a slope such as a start on an uphill by applying a set torque according to the detection state of the inclinometer. For this reason, an inclinometer is required, and when the vehicle is approaching an uphill while creeping on a flat road, control for changing the set torque is required, and the number of components is increased, which complicates the control. Was. In addition, the conventional creep control device can cope with the road gradient by the inclinometer, but keeps the creep torque constant. Can not do. For this reason, if the number of occupants of the vehicle or the load capacity of the vehicle fluctuates, there is a problem that the creep running condition changes even on the same road surface, the creep force becomes insufficient, and the vehicle retreats.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a creep control device for an electric vehicle that enables stable creep running irrespective of changes in vehicle conditions.

[0006]

In order to achieve the above object, according to the present invention, the stop state of the vehicle is detected by the stop detecting means, and the depression of the brake pedal is released by the brake pedal depressing state detecting means. Is detected, the output of the motor is controlled by the creep control means so that the vehicle reaches the set creep vehicle speed, so that a uniform creep vehicle speed is obtained irrespective of changes in the situation of the vehicle.

In order to achieve the above object, according to the present invention, the vehicle speed detecting means detects that the vehicle speed of the vehicle has fallen below a predetermined value, and the brake pedal depressed state detecting means detects the depression of the brake pedal. Is detected, the output of the motor is controlled by the creep control means so that the vehicle reaches the set creep vehicle speed, so that a uniform creep vehicle speed is obtained irrespective of the situation change of the vehicle.

Then, the output of the motor is controlled by varying the set vehicle speed in accordance with the degree of depression of the brake pedal detected by the brake pedal depression state detecting means, and the creep vehicle speed is adjusted in accordance with the brake operation.
Also provided is an actual creep vehicle speed detecting means for detecting an actual creep vehicle speed, and the output of the motor is proportionally integrated based on the set creep vehicle speed and the actual creep vehicle speed detected by the actual creep vehicle speed detecting device, thereby setting creep. Converge to vehicle speed.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a schematic structure of an electric vehicle provided with a creep control device according to an embodiment of the present invention.
2 is a block diagram of the creep control device, FIG. 3 is a flowchart of the creep control device, FIG. 4 is a graph showing vehicle speed conditions for creep running, and FIG. 5 shows a relationship between creep vehicle speed and brake pedal depression amount. A graph is shown.

As shown in FIG. 1, an electric vehicle is of a series type including two motors 1 for driving a drive system of the vehicle and an engine 2 dedicated to power generation. The driving force of the motor 1 is output from the transmission 3 to the output shaft 4, and the driving force is transmitted from the output shaft 4 to the driving wheels 6 via the differential 5. A generator 7 is connected to the engine 2. The generator 7 generates electric power by driving the engine 2, and electric power generated by the generator 7 is stored in a battery 8. In addition, the present invention
The present invention can be applied to not only a series electric vehicle but also a parallel electric vehicle. In addition, the number of motors 1 is not limited to two, and an electric vehicle including one motor 1 may be used.

When the battery runs, the generator 1 is not driven by the engine 2 to generate power (engine power generation), but the motor 1 is driven by the electric power supplied from the battery 8. During hybrid driving, engine power generation is performed, and the generated power is used to charge the battery 8 and simultaneously drive the motor 1. Further, at the time of deceleration, the motor 1 operates as a generator to generate electric power (regenerative power generation), and electric power is regenerated from the motor 1 side to the battery 8 side, and the battery 8 is also charged by the regenerated electric power. That is, the battery 8 discharges the driving power to the motor 1 and charges the power generated by the generator 7 and the regenerative power of the motor 1.

The above-mentioned electric vehicle has an accelerator depression sensor 1 for detecting the depression amount of an accelerator pedal 10.
1 is provided, and a depression sensor 13 as a brake pedal depression state detecting means for detecting a depression amount (depression state) of the brake pedal 12 is provided. Further, the output shaft 4 of the transmission 3 is provided with a vehicle speed sensor 14 for detecting the vehicle speed of the vehicle based on the rotation speed of the output shaft 4 to detect the stopped state of the vehicle.

The information detected by the accelerator depression sensor 11, the depression sensor 13, and the vehicle speed sensor 14 is transmitted to a control unit (E
CU) 15, the output of the motor 1 is controlled in accordance with the operating conditions of the accelerator pedal 10 and the brake pedal 12, the vehicle speed, and the like, thereby ensuring the same driving operability as that of a normal vehicle. Then, the creep control means 1 of the ECU 15
By controlling the output of the motor 1 by the motor 6, creep running is enabled. That is, when the stop state of the vehicle is detected and the depression sensor 13 detects that the depression of the brake pedal 12 is released, the output of the motor is controlled by the creep control means 16 so that the vehicle reaches the set creep vehicle speed. It has become.

The configuration of the creep control device will be described with reference to FIG.

The creep control means 16 of the ECU 15 is provided with a vehicle stop detecting means 21 to which information detected by the vehicle speed sensor 14 is inputted. Stop detection means 21
In the above, the stopped state of the vehicle is detected in accordance with the vehicle speed, for example, a low-speed running state during the deceleration process or a low-speed running state after the vehicle speed becomes zero, and creep is performed based on the stopped state of the vehicle. It is determined whether traveling is permitted. Further, the creep control means 16 is provided with a release determination means 22, and the detection information of the depression sensor 13 is input to the release determination means 22. The release determining means 22 detects the depression amount of the brake pedal 12 and
Is detected, and whether or not the depression is released is detected.

The information from the cancellation determining means 22 is transmitted to the variable means 2
3 and the preset creep vehicle speed is input to the variable means 23. The variable means 23 has a function of changing and setting the set creep vehicle speed according to the depression amount of the brake pedal 12 input from the release determination means 22. The set creep vehicle speed set by the variable means 23 is input to the comparing means 24.

On the other hand, the detection information of the accelerator depression sensor 11 is input to the torque comparison means 26, and the torque comparison means 26 calculates the accelerator torque obtained from the detection information of the accelerator depression sensor 11 and the set creep vehicle speed set by the variable means 23. The creep torque required for the maintenance is compared, and the comparison result is input to the comparing means 24.

In the comparing means 24, a deviation between the actual creep vehicle speed inputted from the vehicle speed sensor 14 (actual creep vehicle speed detecting means) and the set creep vehicle speed set by the variable means 23 is obtained, and the creep torque corresponding to the deviation is calculated. Output to the motor control means 25. That is, the output of the motor 1 is integrated and controlled based on the actual creep vehicle speed and the set creep vehicle speed. The drive of the motor 1 is controlled by the motor control means 25, and the output of the motor 1 is controlled so as to attain the finally set vehicle speed.

The operation of the creep control device will be described with reference to FIGS.

As shown in FIG. 3, it is determined in step S1 whether a vehicle speed condition under which creep running is permitted is satisfied. That is, as shown in FIG. 4, during deceleration, creep running is prohibited until the vehicle speed becomes 0, and once the vehicle speed becomes 0, creep running is allowed until the vehicle speed becomes H (for example, 10 km / h). (Stop detection means 21). That is, the vehicle is in a stopped state from the time when the vehicle speed once becomes 0 to the time when the vehicle speed becomes H, and the creep running is permitted.

When it is determined in step S1 that the vehicle speed condition has been satisfied, it is determined in step S2 whether the depression release condition has been satisfied. That is, as shown in FIG. 5, when the depression amount of the brake pedal 12 detected by the depression sensor 13 exceeds k% (for example, 50%), creep running is prohibited, and the depression amount of the brake pedal 12 is reduced from 0%. Up to k%, creep traveling is permitted at a creep vehicle speed [maximum hkm / h (set creep vehicle speed): for example, 4 km / h] according to the amount of depression (release determination means 22, variable means 2)
3). That is, when the depression of the brake pedal 12 is released, the creep running is permitted at the set creep vehicle speed (maximum hkm / h). Further, even when the depression of the brake pedal 12 is not completely released (the depression amount is up to k%), creep traveling is permitted at a creep vehicle speed corresponding to the depression amount.

If it is determined in step S2 that the depression release condition is satisfied, it is determined in step S3 whether the accelerator torque condition is satisfied. That is, the accelerator torque obtained from the detection information of the accelerator depression sensor 11 is compared with the creep torque required to maintain the set creep vehicle speed. As a result of the comparison, when the accelerator torque is equal to or greater than the creep torque, the creep running is prohibited, and when the accelerator torque is less than the creep torque, the creep running is permitted (torque comparing means 26). That is, creep running is permitted when the accelerator pedal 10 is depressed little.

If all of the conditions in steps S1 to S3 are satisfied, a creep control with a constant vehicle speed is executed in step S4. That is, the output of the motor 1 is controlled so as to maintain the set creep vehicle speed with a creep torque corresponding to a deviation (creep vehicle speed difference) between the actual creep vehicle speed and the set creep vehicle speed set by the variable means 23 (comparing means) 24, motor control means 25). If any of the conditions of steps S1 to S3 is not satisfied, the process proceeds to step S5, and the creep control is not performed.

That is, the output of the motor 1 is proportionally integrated controlled based on the actual creep vehicle speed and the set creep vehicle speed, and the set creep vehicle speed is maintained at a creep torque according to the creep vehicle speed difference. As a result, the time during which the creep vehicle speed difference is large is longer on an uphill road than on a flat road, and a large creep torque is maintained. For example, even if the gradient is about 15%, the creep vehicle speed difference increases and the creep torque also increases, and it is possible to prevent the vehicle from retreating.

By providing the creep control device described above, the stop state of the vehicle is detected and the depression sensor 13
When it is detected that the depression of the brake pedal 12 is released (including the depression amount up to k%), the output of the motor 1 is controlled by the creep control means 16 so that the vehicle reaches the set creep vehicle speed. The output of the motor 1 can be increased until the set creep vehicle speed is reached even when starting on an uphill road or when a heavy object is being loaded. Therefore, the vehicle can start stably without retreating when starting uphill, and can perform stable creep running with good responsiveness even if the running resistance changes, thereby improving the feeling of creep running.

The output of the motor 1 is controlled so that the vehicle reaches the set creep vehicle speed.
Even when a transmission having a plurality of gear positions is provided, a uniform creep vehicle speed can be obtained regardless of the gear position, and the feeling of creep running can be improved. Further, since the creep vehicle speed is made variable in accordance with the amount of depression of the brake pedal 12, a delicate creep vehicle speed operation becomes possible in accordance with the operation of the brake pedal 12. Further, the output of the motor 1 is controlled so as to maintain the set creep vehicle speed with a creep torque corresponding to a deviation (creep vehicle speed difference) between the actual creep vehicle speed and the set creep vehicle speed. Corresponding creep torque can be maintained, and it is easy to converge to the set creep vehicle speed.

An electric vehicle equipped with a creep control device according to another embodiment of the present invention will be described with reference to FIGS. FIG. 6 is a block diagram of a creep control device according to another embodiment, FIG. 7 is a flowchart of the creep control device, and FIG. 8 is a graph showing vehicle speed conditions for creep traveling. In FIG. 6, the same members (functions) as those shown in FIG. 2 are denoted by the same reference numerals, and redundant description is omitted. In FIG. 8, the same steps as those shown in FIG. 3 are denoted by the same step numbers, and overlapping descriptions are omitted.

As shown in FIG. 6, the creep control means 16 of the ECU 15 is provided with a predetermined value comparing means 31 instead of the vehicle stop detecting means 21 in FIG.
1 is input with information detected by a vehicle speed sensor 14 as vehicle speed detecting means. The predetermined value comparing means 31 determines whether or not the vehicle speed has been set such that creep running is permitted according to the vehicle speed. That is, when the vehicle speed becomes equal to or less than the predetermined value, creep running is permitted. Other configurations are the same as those of the creep control device shown in FIG.

The operation of the creep control means 16 will be described. As shown in FIG. 7, in step S11, it is determined whether the vehicle speed has fallen below a predetermined value. That is, as shown in FIG. 8, when the vehicle speed is equal to or lower than a predetermined value H (for example, 10 km / h), creep running is permitted, and when the vehicle speed exceeds the predetermined value H, creep running is prohibited. That is, creep running is permitted when the vehicle speed is equal to or lower than the predetermined value H (for example, 10 km / h) regardless of the running condition. If it is determined in step S11 that the vehicle speed has fallen below the predetermined value,
Moving to step S2, the same control as the operation described in FIG. 3 is performed.

By providing the above-described creep control device, a state where the vehicle speed is equal to or lower than a predetermined vehicle speed is detected, and when the depression sensor 13 detects that the depression of the brake pedal 12 is released, the vehicle reaches the set creep vehicle speed. Since the output of the motor 1 is controlled by the creep control means 16, even when the vehicle starts moving on an uphill road or when a heavy object is loaded, the motor 1 is controlled until the set creep vehicle speed is reached, as in the above-described embodiment. Output can be increased.
Therefore, when the vehicle starts moving uphill, the vehicle can start stably without retreating, and even if the running resistance changes, stable creep running can be performed with good responsiveness. Even when the vehicle travels at a low speed, the creep traveling can be performed without stopping the vehicle, and the feeling of the creep traveling can be improved.

[0031]

According to the first aspect of the present invention, when the stationary state of the vehicle is detected by the stationary state detecting means and the depressing of the brake pedal is detected by the depressing state detecting means of the brake pedal, the creep controlling means detects the state. Since the output of the motor is controlled so that the vehicle reaches the set creep vehicle speed, a uniform creep vehicle speed can be obtained irrespective of a change in the situation of the vehicle. As a result, the output of the motor can be increased until the set creep vehicle speed is reached even when starting on an uphill road or when a heavy object is loaded, so that the vehicle can start stably without retreating when starting on an uphill road. In addition to this, even if the running resistance changes, stable creep running can be performed with good responsiveness, and the feeling of creep running can be improved.

According to the second aspect of the present invention, the vehicle speed detecting means detects that the vehicle speed has fallen below the predetermined value, and the brake pedal depressed state detecting means detects that the brake pedal is released. Then, the output of the motor is controlled by the creep control means so that the vehicle reaches the set creep vehicle speed, so that a uniform creep vehicle speed can be obtained irrespective of changes in the situation of the vehicle.
As a result, the output of the motor can be increased until the set creep vehicle speed is reached even when starting on an uphill road or when a heavy object is loaded, so that the vehicle can start stably without retreating when starting on an uphill road. As well as being able to perform stable creep running with good responsiveness even if the running resistance changes,
Even when the vehicle travels at a low speed continuously, such as during traffic congestion, the creep traveling can be performed without stopping the vehicle, and the creep traveling feeling can be improved.

According to the third aspect of the present invention, the output of the motor is controlled by varying the set vehicle speed in accordance with the degree of depression of the brake pedal detected by the brake pedal depression state detecting means. Subtle creep vehicle speed adjustment is possible according to the operation.

In the invention according to claim 4, the output of the motor is proportionally integrated based on the set creep vehicle speed and the actual creep vehicle speed, so that the creep torque according to the running resistance can be maintained. In addition, it becomes possible to easily converge to the set creep vehicle speed.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an electric vehicle including a creep control device according to an embodiment of the present invention.

FIG. 2 is a block diagram of a creep control device.

FIG. 3 is a flowchart of a creep control device.

FIG. 4 is a graph showing vehicle speed conditions for creep running.

FIG. 5 is a graph showing a relationship between a creep vehicle speed and a brake pedal depression amount.

FIG. 6 is a block diagram of a creep control device according to another embodiment of the present invention.

FIG. 7 is a flowchart of a creep control device.

FIG. 8 is a graph showing vehicle speed conditions for creep running.

[Explanation of symbols]

 Reference Signs List 1 motor 2 engine 7 generator 8 battery 11 accelerator depression sensor 13 depression sensor 14 vehicle speed sensor 15 control device (ECU) 16 creep control device 21 stop detection means 22 release determination means 31 predetermined value comparison means

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Claims (4)

[Claims] 1. A battery for charging and discharging power, a motor for driving a drive system of a vehicle with the power supplied from the battery, a stop detecting means for detecting a stop state of the vehicle, and a stepping state of a brake pedal. When the brake pedal depressed state detecting means and the vehicle stop detecting means detect the stopped state of the vehicle and the brake pedal depressed state detecting means detects that the brake pedal is released, the vehicle is set to creep. A creep control device for an electric vehicle, comprising: creep control means for controlling the output of the motor so as to be at a vehicle speed. 2. A battery for charging and discharging power, a motor for driving a drive system of a vehicle with the power supplied from the battery, vehicle speed detecting means for detecting the vehicle speed of the vehicle, and detecting a depression state of a brake pedal. The brake pedal depressed state detecting means and the vehicle speed detecting means detect that the vehicle speed of the vehicle has fallen below a predetermined value, and the brake pedal depressed state detecting means detects that the brake pedal has been depressed. And a creep control means for controlling the output of the motor so that the vehicle has a set creep vehicle speed. 3. The creep control means according to claim 1, wherein said creep control means is configured to vary said set creep vehicle speed in accordance with a degree of depression of a brake pedal detected by said brake pedal depression state detection means. A creep control device for an electric vehicle, having a function of controlling the output of a motor. 4. The vehicle according to claim 1, further comprising an actual creep vehicle speed detecting means for detecting an actual creep vehicle speed, wherein the creep control means includes the set creep vehicle speed and the actual creep vehicle speed. A creep control device for an electric vehicle, comprising a function of performing proportional-integral control on the output of the motor based on the actual creep vehicle speed detected by the detection means.