JPH1175304A - Motor torque controller of electric vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a motor torque controller of an electric vehicle to improve its operability by alleviating pedal operation and the like during traffic congestion. SOLUTION: A motor torque controller 1 has a detection unit 2, a control unit 3 and an output unit 4. The detection unit 4 comprises an accelerator operation detecting means 6, a braking stroke detecting means 7 and a vehicle speed detecting means 8 and the like. The control unit 3 is composed of a memory means 15, a judging means 16, an arithmetic means 17 and an indicating means 18. The means 15 comprises a first to a seventh memory unit 19 to 24 and 38. The judging means 16 comprises a first to a third judging unit 27 to 29. The arithmetic means 17 comprises a first to a fifth operating units 30 to 34. A third operating unit 32 calculates the target vehicle speed during traffic congestion. The third judging unit 29 judges whether the road is congested. The indicating means 18 adds powering and regeneration torques to the creeping toque. A second operating unit 31 controls the vehicle speed V.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motor torque control device for an electric vehicle, which generates a torque corresponding to the creep torque of a vehicle equipped with an automatic transmission.

[0002]

2. Description of the Related Art In an electric vehicle, when the motor torque is controlled so that the motor torque becomes zero when the operation amount of the accelerator is zero, a creep torque like a vehicle equipped with an automatic transmission (hereinafter referred to as an automatic vehicle) is generated. do not do. For this reason, the driving operation becomes troublesome and difficult for a driver who has become a driver of the automatic vehicle.

[0003] Therefore, conventionally, a motor torque control device that generates torque to a motor when both an accelerator pedal and a brake pedal are not operated has been used. This motor torque control device generates a torque equivalent to the creep torque of an automatic vehicle by generating a constant torque in the motor.

[0004]

The above-described conventional motor torque control device merely generates a constant torque in the motor, so that during a traffic jam, the accelerator pedal is adjusted to match the traveling speed of the surrounding vehicle. And it was necessary to frequently operate the brake pedal.

[0005] Further, the conventional motor torque control device generates creep torque after the brake pedal operation is stopped, so that the vehicle may retreat when starting on a slope.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a motor torque control device for an electric vehicle which reduces pedal operation and the like during traffic congestion and suppresses backward movement when starting on a slope to improve operability.

[0007]

According to a first aspect of the present invention, there is provided a motor torque control device for an electric vehicle, wherein the target vehicle speed setting unit obtains an average vehicle speed obtained by the vehicle speed detection unit. The vehicle speed control means controls the vehicle speed based on the target vehicle speed based on the target vehicle speed based on the target vehicle speed.

Further, since the creep torque is generated when the brake operation amount becomes equal to or less than a predetermined value, the vehicle is prevented from retreating when starting on a slope, and starts smoothly even when starting on a flat road.

In the motor torque control device for an electric vehicle according to the present invention, the congestion determining means determines whether or not there is congestion from the average vehicle speed and the traveling time ratio, so that the traveling state is reliably determined. . Further, since the target vehicle speed setting means for congestion sets the target vehicle speed when it is determined that there is congestion, the operation of the accelerator and the brake pedal during traffic congestion and the like is further reduced.

Further, the congestion determination means determines whether or not the vehicle is on a congested road at predetermined intervals based on an average vehicle speed and a ratio of time when the vehicle speed is equal to or higher than a predetermined value and time when the vehicle speed is lower than the predetermined value. A control unit that sets a target vehicle speed based on a running average vehicle speed calculated in a cycle shorter than the predetermined cycle when the traffic congestion target vehicle speed setting unit is a map and the traffic congestion determination unit determines that the road is a congested road. Desirably a map.

In this case, since the cycle for detecting the average vehicle speed used to set the target vehicle speed during the traffic jam is shorter than the cycle for the traffic jam determining means to determine whether or not the traffic is congested, the traffic is more reliably congested. And a more appropriate target vehicle speed can be set. Therefore, the operation of the accelerator and the brake pedal can be further reduced during a traffic jam, and the operability can be further improved.

According to the third aspect of the present invention, the motor torque control device for an electric vehicle generates a creep torque when the brake operation amount becomes equal to or less than a predetermined value. The vehicle starts smoothly even when starting on a flat road.

Further, since no creep torque is generated when the parking brake is operated, overheating of the motor can be prevented and the reliability of the motor and the like can be ensured.

According to a third aspect of the present invention, there is provided a motor torque control device for an electric vehicle according to the present invention, wherein a target vehicle speed at the time of traveling based on the creep torque is set based on an average vehicle speed obtained from the vehicle speed detected by the vehicle speed detecting means. It is desirable to have target vehicle speed setting means for performing the control, and vehicle speed control means for controlling the vehicle speed based on the creep torque based on the target vehicle speed set by the target vehicle speed setting means.

In this case, the target vehicle speed setting means sets the target vehicle speed based on the creep torque based on the average vehicle speed obtained by the vehicle speed detecting means, and the vehicle speed control means controls the vehicle speed based on the target vehicle speed. Acceleration and brake pedal operation are reduced. Therefore, operability can be further improved.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. As shown in FIG. 1, a motor torque control device 1 for an electric vehicle includes a detection unit 2, a control unit 3, an output unit 4, and the like.

The detecting section 2 comprises a road gradient detecting means 5, an accelerator operation detecting means 6, a brake operation amount detecting means 7, a vehicle speed detecting means 8, a motor speed detecting means 9, and the like. The accelerator operation detecting means 6 detects an on / off operation and an operation amount of an accelerator pedal, and detects the control unit 3.
, An accelerator pedal operation signal Ac is output. The brake operation amount detecting means 7 detects the ON / OFF operation and the operation amount of the brake pedal, and outputs a brake pedal operation amount signal Br to the control unit 3.

The vehicle speed detecting means 8 is obtained by a known speed sensor capable of detecting the rotation of the wheels 14 and the like, detects the vehicle speed of the electric vehicle, and outputs a vehicle speed signal V to the control unit 3. I have.

The motor rotation speed detecting means 9 is connected to the output unit 4.
And outputs the motor rotation speed signal Mt to the control unit 3 by detecting the rotation speed of the motor 12.

Further, if necessary, when a transmission is provided in the electric vehicle, a shift position detecting means 10 for detecting a shift position of the transmission and outputting a shift position signal St to the control unit 3 is provided. It is desirable.

The road gradient detecting means 5 calculates, among the forces acting on the vehicle traveling on the road, the force directed along the road and toward the rear of the vehicle, that is, the so-called gradient resistance Kr. It has the function of outputting to the user. The gradient resistance Kr calculated by the road gradient detecting means 5
Is a combination of a force generated by gravitational acceleration and a force due to friction from a road surface or the like on an uphill having a gradient.

The road gradient detecting means 5 includes a tire driving force F obtained from the torque output from the motor 12 and the like.
The gradient resistance Kr is calculated using Expression 1 derived from the fact that the sum of the acceleration resistance Ra acting on the vehicle during traveling and the traveling resistance is substantially equal.

W × sin θ = F−Ra−W × μr−μc × S × V ² −Rc (1) where W × sin θ: slope resistance W: gross vehicle weight θ: slope F: tire driving force or Tire braking force Ra: acceleration resistance μr: rolling resistance coefficient μc: air resistance coefficient S: vehicle front projected area V: vehicle speed Rc: turning resistance Note that the road gradient detecting means 5 is used before running such as the total vehicle weight W. A clear numerical value is stored, and a numerical value such as a vehicle speed V that needs to be detected during traveling is supplied from the vehicle speed detecting means 8 or the like. As described above, the road gradient detecting means 5 calculates the road gradient based on the balance of the force related to the traveling of the vehicle, and estimates the road gradient.

The output section 4 comprises a power conversion circuit 11. The power conversion circuit 11 includes a motor 12
And the battery 13 are connected. Power conversion circuit 11
Is an inverter or the like, and controls the powering torque of the motor 12 by changing the frequency and the like of the voltage supplied from the battery 13 and applied to the motor 12 in accordance with a later-described final command torque TT output from the control unit 3. It has the function to do. The power conversion circuit 11 has a function of controlling a regenerative torque for accumulating electric power generated by forcibly rotating the motor 12 in the battery 13.

The motor 12 has a wheel 14 as an output shaft.
And the motor rotation speed detecting means 9 and the like are connected. The motor 12 generates a powering torque for driving the wheels 14 by applying a voltage supplied from the battery 13 through the power conversion circuit 11, and also generates electric power by being forcibly rotated by the wheels 14. I do.

The control section 3 comprises a storage means 15, a determination means 16, a calculation means 17, and an instruction means 18. The control unit 3 calculates a final command torque TT based on the signals Kr, Ac, Br, V, St, and Mt output from the detection unit 2 and outputs the calculated torque to the power conversion circuit 11. I have.

The storage means 15 comprises a first storage unit 19, a second storage unit 20, a third storage unit 21, and a fourth storage unit 2.
It has a second storage unit 23, a fifth storage unit 23, a sixth storage unit 24, and a seventh storage unit 38.

The first storage unit 19 sets the first predetermined torque obtained from the maximum torque of the motor 12 and the like as an upper limit,
And the calculated gradient resistance K output by the road gradient detecting means 5
A first map for calculating a first command creep torque KT1 proportional to r is stored. The second storage unit 20
Is the vehicle speed signal V (vehicle speed) output by the vehicle speed detecting means 8
The second map in which the gain becomes smaller as the time becomes faster is stored.

This second map is a vehicle speed signal V (vehicle speed).
Is faster than a target vehicle speed VL outputted via a third determination unit 29 of the calculating means 17 described later, the gain is gradually reduced in inverse proportion to the vehicle speed signal V. When the vehicle speed signal V exceeds the sum of the target vehicle speed VL and the first predetermined vehicle speed, the gain becomes zero. It is desirable that the first predetermined vehicle speed is a relatively low speed such as 5 km / h. Therefore, the actual running vehicle speed V is a speed between the target vehicle speed VL and the sum of the target vehicle speed VL and the first predetermined vehicle speed.

The second map shows the vehicle speed signal V
When (vehicle speed) is higher than 0 and lower than the target vehicle speed VL, the first predetermined gain is maintained. When the vehicle speed signal V is negative, that is, when the vehicle is moving backward, the second predetermined gain is set as an upper limit and the gain is increased from the first predetermined gain as the vehicle speed decreases, that is, as the reverse vehicle speed increases. Is proportionally increased.

The third storage unit 21 stores a third map 25 as target vehicle speed setting during traffic congestion for calculating a target vehicle speed VL during creep running from the vehicle speed signal V. The third map 25 is used to calculate the target vehicle speed VL when a third determination unit 29, which will be described later, of the determination unit 16 determines that the road is a congested road.

As shown in FIG. 3, the third map 25 indicates that the target vehicle speed VL has the lower limit of the second predetermined vehicle speed Vs and the upper limit of the maximum target vehicle speed VLlim, and the vehicle speed signal (vehicle speed) V The speed is proportional to the first average vehicle speed Va as the average vehicle speed during traveling obtained from the above.

The first average vehicle speed Va is set to a stop state (V = 0 km) within a relatively short cycle such as 30 seconds.
The average value of the vehicle speed V excluding / h) is used. The second predetermined vehicle speed Vs is desirably set to an extremely low speed such as 2 km / h, and the maximum target vehicle speed VLlim is set to a speed such as 20 km / h in order to ensure vehicle safety and the like. It is desirable.

The first average vehicle speed Valim when the calculated target vehicle speed VL reaches the maximum target vehicle speed VLlim is:
It is desirable to make the sum equal to the sum of the maximum target vehicle speed VLlim and the first predetermined vehicle speed. When the first predetermined vehicle speed is 5 km / h, the average vehicle speed Valim is 2
It becomes 5 km / h.

The fourth storage unit 22 stores the third predetermined gain as an upper limit, and the accelerator operation detecting means 6 does not detect the accelerator operation and the brake operation amount detected by the brake operation amount detecting means 7 has a predetermined value. A fourth map for calculating a gain proportional to the elapsed time after the following is stored. In the fourth map, the gain is 0 when one or both of the accelerator operation amount and the brake operation amount are equal to or more than a predetermined value.

The first predetermined time during which the third predetermined gain is equal to the gain calculated by the fourth map is calculated according to the calculated gradient resistance Kr calculated by the road gradient detecting means 5. desirable. At this time, it is desirable that the first predetermined time is shortened as the calculated gradient resistance Kr increases, that is, as the gradient of the road becomes steeper.

The fifth storage unit 23 stores the judgment means 1
In a case where the motor 12 is overheated and the motor 12 is overheated by the second determination unit 28 described later, the accelerator operation detection means 6 does not detect the accelerator operation and the brake operation amount detection means 7 5 stores a fifth map in which the gain gradually decreases with the elapsed time after the detected brake operation amount becomes equal to or less than the predetermined value.

As shown in FIG. 4, the sixth storage section 24 stores the sixth average vehicle speed Vaa and the traveling time ratio Vra to determine whether or not the vehicle is on a congested road.
Map 26 is stored. The second average vehicle speed Va
a is the vehicle speed V within a relatively long cycle such as 3 minutes.
Is the average value.

In the present embodiment, the second average vehicle speed V
aa is obtained by selecting six latest ones from the average vehicle speeds every 30 seconds and calculating the average value of these six average vehicle speeds. The running time ratio Vra
Indicates the ratio of the predetermined time to the time during which the vehicle is actually traveling within the predetermined time, that is, the vehicle speed is higher than 0 km / h as the predetermined value.

The sixth map 26 indicates that if the second average vehicle speed Vaa is in a region P1 where the traveling speed ratio Vra is relatively low and the traveling time ratio Vra is relatively low, it is determined that the road is a congested road, and the second average vehicle speed Vaa Is relatively high speed and the traveling time ratio Vra is relatively high in the region P2, it is determined that the road is not a congested road.

The determination boundaries K1 and K2 of the sixth map 26 for determining whether or not the road is a congested road have hysteresis to prevent chattering and the like, as shown in FIG. , The second average vehicle speed Vaa gradually decreases.

For example, when it is determined that the state of the area P1 determined as a congested road is shifted to the state of an area P2 which is not a congested road, the second average vehicle speed Vaa is relatively high and the traveling time ratio First determination boundary K where Vra is relatively high
1 is used. When it is determined that the state of the area P2 which is not a congested road is shifted to the state of the area P1 which is determined to be a congested road, the second average vehicle speed Vaa
Are used at a relatively low speed and a relatively low traveling time ratio Vra is used.

The seventh storage unit 38 sets an extremely low speed such as the second predetermined vehicle speed Vs as a target vehicle speed VL when a third determination unit 29 described later determines that the road is not a congested road. Is output to the calculation unit 31.

The determination means 16 includes a first determination unit 27
, A second determination unit 28, and a third determination unit 29. The first determination unit 27, as shown in FIG.
It has a function of determining whether or not to generate creep torque. The first determination unit 27 does not generate a creep torque when the brake pedal operation amount is equal to or more than a predetermined value, and generates a creep torque in other cases.

The second judging section 28 has a function of judging whether or not the motor is overheated. The second determination unit 28
When the motor 12 is in a motor locked state in which the motor 12 is easily overheated and the rotation speed is lower than a predetermined rotation speed and the torque is higher than a second predetermined torque, the motor 12 has a function of determining a motor overheating condition. The predetermined rotation speed and the second predetermined torque are:
It is desirable to set it based on the performance and specifications of the motor 12.

The third judging section 29 stores the sixth map 2 in the storage means 15 as indicated by an arrow R shown in FIGS.
6 can be read freely. The third determination unit 29
Using the sixth map 26, a function is provided for determining whether or not the vehicle is traveling on a congested road.

The third judging section 29 outputs the target vehicle speed VL calculated by the third calculating section 32 described later to the second calculating section 31 described later when the traffic jam road is determined. I have.

The calculating means 17 includes a first calculating unit 30
, A second operation unit 31, a third operation unit 32, a fourth operation unit 33, and a fifth operation unit 34. The calculation means 17 can read the first map to the fifth map of the storage means 15 as shown by the arrow R in the drawing.

As shown in FIG. 2, the first calculating section 30 uses the first map of the first storage section 19 to calculate the first slope from the calculated slope resistance Kr output by the road slope means 5.
Is calculated, and the second calculation unit 3
1 is output.

The second calculating section 31 calculates the vehicle speed signal V output from the vehicle speed detecting means 8, the target vehicle speed VL output via the third determining section 29, and the second storage section 20 of the second storage section 20.
The first command creep torque KT1 calculated by the first calculation unit 30 is multiplied by the gain obtained by using the map of (1), and the second command creep torque KT2 is transmitted to the fourth calculation unit 33. Output. Note that the second arithmetic unit 31 and the second storage unit 20 constitute a vehicle speed control unit described in this specification.

When the third determination section 29 determines that the road is a congested road, the third calculation section 32 uses the third map 25 of the third storage section 21 to detect vehicle speed. The target vehicle speed VL is calculated from the vehicle speed signal V output by the controller 8 and output to the third determination unit 29. The third computing unit 32, the third storage unit 21, the third determination unit 29, and the sixth storage unit 24
And the seventh storage unit 38 constitute the target vehicle speed setting means described in this specification.

The fourth arithmetic unit 33 calculates the gain obtained by using the fourth map of the fourth storage unit 22 with the second command creep torque K output by the second arithmetic unit 31.
The second command creep torque KT3 is output by multiplying T2.

In the fourth map, since the gain is 0 when either or both of the accelerator operation amount and the brake operation amount are equal to or more than the predetermined value, the accelerator operation and the brake operation amount are equal to or more than the predetermined value. If either one or both are detected, the fourth
Will not generate the creep torque. The first computing unit 30, the first storage unit 19, the fourth computing unit 33, and the fourth storage unit 2
2 and the first determination unit 27 constitute a creep torque control unit described in this specification.

When the second determination section 28 determines that the motor is overheated, the fifth calculation section 34 calculates the gain obtained by using the fifth map in the fifth storage section 23. The third command creep torque KT3 output by the fourth calculation unit 33 is multiplied to output a fourth command creep torque KT4.

The instruction means 18 is, as shown in FIG.
The fourth command creep torque KT4 obtained through the first calculation unit 30 to the fifth calculation unit 34 or the third command creep obtained through the first calculation unit 30 to the fourth calculation unit 33 The final command torque TT is calculated by adding the regenerative torque command signal BT and the powering torque command signal AT by the accelerator pedal 35 to the torque KT3,
The final command torque TT is output to the power conversion circuit 11.

In the control section 3, as shown in FIG. 2, the command creep torques KT3 and KT4 are applied between the fifth arithmetic section 34 and the instruction means 18 by the motor 1 as shown in FIG.
It is desirable to provide a limiter section 36 which does not exceed the maximum torque of 2.

When a transmission is provided, it is desirable to provide a shift compensator 37 for correcting the creep torque according to the shift position of the transmission. In the illustrated example, it is provided between the first arithmetic unit 30 and the second arithmetic unit 31.

According to the above-described configuration, as shown in FIG. 5, first, in step S1, it is determined whether or not to generate a creep torque. In step S1, the first determination unit 27 determines whether the operation amount of the brake pedal is equal to or less than a predetermined value. If the operation amount of the brake pedal is equal to or less than the predetermined value, the process proceeds to steps S2 and S3. .

In step S2, the first computing section 30 computes the first command creep torque KT1 and proceeds to step S2.
Proceed to 6. In step S3, the third determination unit 29 determines whether or not the road is a congested road. If it is determined that the road is a congested road, the process proceeds to step S4. If it is determined that the road is not a congested road, the process proceeds to step S5.

In step S4, the third operation unit 32
Calculates the target vehicle speed VL based on the third map 25 and proceeds to step S6, and in step S5, sets the second predetermined vehicle speed Vs as the target vehicle speed VL and proceeds to step S6.

In step S6, the second operation unit 31
Multiplies the first command creep torque KT1 by a gain based on the second map to obtain a second command creep torque K
T2 is calculated, and the process proceeds to step S7.

In step S7, the fourth operation unit 33
Calculates the third command creep torque KT3 by multiplying the second command creep torque KT2 calculated in step S6 by a gain based on the fourth map.
Proceed to 8.

In step S8, the second determination unit 28
Is determined whether or not the motor is overheated. Second determination unit 28
As described above, if it is determined that the motor is overheated, the process proceeds to step S9, and if it is determined that the motor is not overheated, the process proceeds to step S10.

In step S9, the fifth command section 34 multiplies the third command creep torque KT3 calculated in step S7 by a gain based on the fifth map.
Is calculated in step S1.
Go to 0.

In step S10, the third command creep torque KT3 calculated in step S7 or the fourth command creep torque KT4 calculated in step S9.
The command means 18 adds the regenerative torque command signal BT and the powering torque command signal AT to the final command torque TT
Is output.

The power conversion circuit 11 controls the voltage applied to the motor 12 in accordance with the final command torque TT obtained in this manner, thereby controlling the creep torque generated by the motor 12. Then, the process from step S1 is repeated.

According to the present embodiment, the third determination section 29 determines whether or not the road is a congested road based on the sixth map 26 shown in FIG. If it is determined that the road is a congested road, the third calculation unit 32 sets the target vehicle speed based on the third map 25 shown in FIG. 3, and the second calculation unit 31 calculates the vehicle speed using the second map. Since the control is performed, the operation of the accelerator and the brake pedal is reduced.

When the third determination section 29 determines that the vehicle is not on a congested road, the target vehicle speed VL is set to the extremely low second vehicle speed VL.
And the second arithmetic unit 31 multiplies the creep torque by a gain based on the second map. For this reason, no creep torque is generated except when the vehicle is traveling at an extremely low speed, so that the driver does not feel uncomfortable.

Since the cycle in which the third calculating section 32 calculates the target vehicle speed VL is shorter than the cycle in which the third judging section 29 judges whether or not the vehicle is on a congested road, the accelerator and the brake can be more reliably performed. The pedal operation is reduced.

Further, since the first calculating section 30 generates a creep torque proportional to the calculated slope resistance Kr calculated by the road slope detecting means 5, an appropriate creep according to the road slope or the like is provided. This will generate torque.

Since the second arithmetic unit 31 reduces the creep torque as the vehicle speed increases, the vehicle can move forward at a substantially constant vehicle speed when climbing a hill or the like. Will be improved. Further, when the vehicle retreats, the second map increases the creep torque, so that the vehicle retreats.

Further, the second arithmetic unit 31 reduces the creep torque when the vehicle speed V exceeds the target vehicle speed VL, and does not generate the creep torque when the vehicle speed V exceeds the sum of the target vehicle speed VL and the first predetermined vehicle speed. The traveling vehicle speed V
Control is performed between the target vehicle speed VL and the sum of the target vehicle speed VL and the first predetermined vehicle speed.

Further, since the fourth arithmetic unit 33 gradually increases the creep torque using the fourth map, the vehicle starts smoothly. The second determination unit 28 determines whether or not the motor is overheated, and when the motor is overheated, the creep torque is gradually reduced. Therefore, the overheating of the motor 12 is suppressed as much as possible. Motor 12
And so on.

Further, since the road gradient detecting means 5 calculates a value obtained by adding the force due to the gravitational acceleration and the force due to the friction of the road surface, etc., the creep corresponding to the inclination angle of the vehicle detected by using a gyro or the like. It is possible to generate a more appropriate creep torque as compared with a case where a torque is generated. In addition, since the creep torque is generated in a state where the braking force before the operation amount of the brake pedal becomes zero remains, even if the operation of the accelerator pedal is delayed on a slope, the vehicle can start smoothly without retreating.

FIGS. 6 and 7 show a second embodiment.
The same components as those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted. As shown in FIG. 6, the motor torque control device 1 according to the present embodiment includes a parking brake operation detecting unit 39 in the detecting unit 2.

The parking brake detecting means 39 detects the on / off operation of the parking brake and outputs a parking brake operation signal Pb to the control unit 3.

The fourth map stored in the fourth storage section 22 of the storage means 15 is the accelerator operation detection means 6.
Is a map for calculating a gain proportional to an elapsed time since the brake operation amount detecting means 7 detects a brake operation amount equal to or less than a predetermined brake operation amount (predetermined value) such as 20% without detecting an accelerator operation. It has become.

In the fourth map, when one or both of the accelerator operation and the brake operation larger than the predetermined brake operation amount are detected, the gain is 0, so that the accelerator operation and the predetermined brake operation amount When either one or both of the larger brake operations are detected, the fourth calculation unit 31 does not generate the creep torque.

The first judging section 27 for judging whether or not to generate a creep torque has a function that the brake pedal operation amount detecting means detects a brake pedal operation amount larger than the predetermined brake operation amount, and the parking brake operation detecting means When the parking brake 39 is detected, the creep torque is not generated, and in other cases, the creep torque is generated.

According to the above-described configuration, as shown in FIG. 7, it is first determined whether or not to generate a creep torque in steps 1a and 1b. In step 1a, the first determination unit 27 determines whether or not the operation amount of the brake pedal is equal to or less than the predetermined brake operation amount. If the operation amount of the brake pedal is equal to or less than the predetermined brake operation amount, step 1a is performed. Proceed to 1b.

In step 1b, the first judging section 27 judges whether the parking brake is operated or not.
If the parking brake has not been operated, the process proceeds to step S2 and step S3.

Thereafter, the processing is performed according to steps S2 to S10 as in the first embodiment. According to this embodiment, when the operation amount of the brake pedal is gradually reduced at the time of starting on a slope, the first operation amount from the time when the operation amount of the brake pedal becomes equal to or less than the predetermined brake operation amount, for example, 20%. The determination unit 27 causes the creep torque to be generated, and the fourth calculation unit 33 gradually increases the creep torque using the fourth map. Therefore, the vehicle starts smoothly without retreating.

When the parking brake is operated, the first judging section 27 does not generate a creep torque, so that the overheating of the motor 12 is suppressed as much as possible and the reliability of the motor 12 and the like is secured.

The third determination section 29 determines whether or not the road is a congested road based on the sixth map 26 shown in FIG. If it is determined that the road is a congested road, the third calculation unit 32 sets the target vehicle speed based on the third map 25 shown in FIG. 3, and the second calculation unit 31 calculates the vehicle speed using the second map. Since the control is performed, the operation of the accelerator and the brake pedal is reduced.

When the third determination section 29 determines that the vehicle is not on a congested road, the target vehicle speed VL is determined to be extremely low in the second vehicle.
And the second arithmetic unit 31 multiplies the creep torque by a gain based on the second map. For this reason, no creep torque is generated except when the vehicle is traveling at an extremely low speed, so that the driver does not feel uncomfortable.

Since the cycle in which the third calculation section 32 calculates the target vehicle speed VL is shorter than the cycle in which the third determination section 29 determines whether or not the vehicle is on a congested road, the accelerator and brake can be more reliably performed. The pedal operation is reduced.

Further, since the first calculating section 30 generates a creep torque proportional to the calculated slope resistance Kr calculated by the road slope detecting means 5, an appropriate creep according to the road slope or the like is provided. This will generate torque.

Since the second arithmetic unit 31 reduces the creep torque as the vehicle speed increases, the vehicle can move forward at a substantially constant vehicle speed when climbing a hill or the like. Will be improved. Further, when the vehicle retreats, the second map increases the creep torque, so that the vehicle retreats.

Further, the second arithmetic unit 31 reduces the creep torque when the vehicle speed V exceeds the target vehicle speed VL, and does not generate the creep torque when the vehicle speed V exceeds the sum of the target vehicle speed VL and the first predetermined vehicle speed. The traveling vehicle speed V
Control is performed between the target vehicle speed VL and the sum of the target vehicle speed VL and the first predetermined vehicle speed.

The second judging section 28 judges whether or not the motor is overheated. If the motor is overheated, the creep torque is gradually reduced. As a result, the reliability of the motor 12 and the like is secured as much as possible.

Further, since the road gradient detecting means 5 calculates a value obtained by adding the force due to the gravitational acceleration and the force due to the friction of the road surface, the creep corresponding to the inclination angle of the vehicle detected by using a gyro or the like. It is possible to generate a more appropriate creep torque as compared with a case where a torque is generated.

[0092]

According to the first aspect of the present invention, the target vehicle speed is set by using the vehicle speed detecting means and the vehicle speed is controlled based on the target vehicle speed, so that the operation of the accelerator and the brake pedal is reduced during a traffic jam or the like. It will be.

Further, when the brake operation amount becomes equal to or less than a predetermined value, a creep torque is generated. Therefore, it is possible to improve the operability at the time of traffic congestion and at the time of starting on a slope.

According to the second aspect of the present invention, in addition to the effect of the first aspect, since it is determined whether or not there is traffic congestion based on the average vehicle speed and the traveling time, the traveling state can be more reliably determined. Further, during a traffic jam, the target vehicle speed setting means at the time of traffic jam sets the target vehicle speed, so that a more appropriate creep torque can be generated. Therefore, the operation of the accelerator and the brake pedal during a traffic jam can be further reduced, and the operability can be further improved.

According to the third aspect of the present invention, the creep torque is generated when the brake operation amount becomes equal to or less than the predetermined value.
The vehicle starts smoothly even when starting on a flat road.
Therefore, operability can be improved.

As a secondary effect, since no creep torque is generated when the parking brake is operated, overheating of the motor can be prevented and the reliability of the motor can be ensured.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a motor torque control device for an electric vehicle according to a first embodiment of the present invention.

FIG. 2 is a block diagram showing a control unit of the motor torque control device of the embodiment shown in FIG.

FIG. 3 is a view showing a third map of the motor torque control device shown in FIG. 2;

FIG. 4 is a view showing a sixth map of the motor torque control device shown in FIG. 2;

FIG. 5 is a flowchart showing a procedure of a process of the motor torque control device shown in FIG. 2;

FIG. 6 is a block diagram showing a motor torque control device for an electric vehicle according to a second embodiment of the present invention.

FIG. 7 is a flowchart showing a procedure of a process of the motor torque control device shown in FIG. 6;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Motor torque control device 6 ... Accelerator operation detection means 7 ... Brake operation amount detection means 8 ... Vehicle speed detection means 12 ... Motor 19 ... First storage unit (creep torque control unit) 20 ... Second storage unit (vehicle speed control) 21) Third storage unit (target vehicle speed setting unit) 22 ... Fourth storage unit (creep torque control unit) 24 ... Sixth storage unit (target vehicle speed setting unit) 25 ... Third map (during congestion) Target vehicle speed setting means) 26: sixth map (congestion determination means) 27: first determination unit (creep torque control means) 29: third determination unit (target vehicle speed setting means) 30: first calculation unit ( Creep torque control means) 31 second calculation unit (vehicle speed control means) 32 ... third calculation unit (target vehicle speed setting means) 33 ... fourth calculation unit (creep torque control means) 38 ... seventh storage unit (Target vehicle speed setting hand ) 39 ... parking brake operation detecting means V ... vehicle speed signal (vehicle speed) VL ... target vehicle speed Va ... first average speed (during running average vehicle speed) Vaa ... second average speed Vra ... travel time ratio

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Hisamitsu Koga 5-33-8 Shiba, Minato-ku, Tokyo Inside Mitsubishi Motors Corporation (72) Inventor Toshiya Maho 5-33-8 Shiba, Minato-ku, Tokyo Mitsubishi Automotive Industry Co., Ltd.

Claims (3)

[Claims] 1. A motor torque control device for an electric vehicle, comprising: vehicle speed detection means for detecting a vehicle speed; accelerator operation detection means for detecting an accelerator operation; and brake operation amount detection means for detecting a brake operation amount. A creep torque control unit that generates a creep torque to the motor when the accelerator operation detection unit does not detect the accelerator operation and the brake operation amount detection unit detects a brake operation amount equal to or less than a predetermined value; Target vehicle speed setting means for setting the target vehicle speed of the vehicle based on the average vehicle speed obtained from the vehicle speed detected by the vehicle speed detection means; and a vehicle speed for controlling the vehicle speed based on the creep torque based on the target vehicle speed set by the target vehicle speed setting means. A motor torque control device for an electric vehicle, comprising: control means. 2. The congestion determining means for judging congestion based on an average vehicle speed and a running time ratio, and a congestion target vehicle speed for setting a target vehicle speed when the congestion judging means judges that the road is a congested road. The motor torque control device for an electric vehicle according to claim 1, further comprising a setting unit. 3. A motor torque control device for an electric vehicle, comprising: vehicle speed detecting means for detecting a vehicle speed; accelerator operation detecting means for detecting an accelerator operation; and brake operation amount detecting means for detecting a brake operation amount. A parking brake operation detecting means for detecting a brake operation, and a creep torque generated in the motor when the accelerator operation detecting means does not detect an accelerator operation and the brake operation amount detecting means detects a brake operation amount equal to or less than a predetermined value. And a creep torque control unit that does not generate a creep torque in the motor when the parking brake operation detecting unit detects the parking brake operation.