JP2010130890A - Vehicle and its method of controlling - Google Patents

Abstract

An object of the present invention is to suppress overheating of an electric motor and to reduce an uncomfortable feeling of a passenger.
When the required torque Td * is less than a threshold value T1 (S120), the motor 22 is controlled so that the required torque Td * is output from the motor 22 for a predetermined time tref (S220 to S250), and then the road surface. The lower limit torque Tmin is set so that the gradient θ increases as the climb gradient increases (S140, S260, S270), and the torque output from the motor 22 is decreased until the lower limit torque Tmin is reached (S160 to S180). As a result, the vehicle slides down the uphill road, so that the state where the current is concentrated on a specific phase of each phase coil of the motor 22 can be alleviated, and overheating of the motor 22 can be suppressed, and the lower limit torque Tmin is reduced to the road surface. Since the gradient θ increases as the climbing gradient increases, the feeling of acceleration can be mitigated when the vehicle moves down the uphill road, thereby reducing the passenger's uncomfortable feeling.
[Selection] Figure 2

Description

  The present invention relates to a vehicle and a control method thereof, and more particularly to a vehicle mounted with an electric motor capable of outputting power to an axle and a control method thereof.

Conventionally, as this type of vehicle, a vehicle in which a traveling motor that outputs power to drive wheels is mounted has been proposed (for example, see Patent Document 1). In this vehicle, the balance torque calculated from the balance of the vehicle on the uphill road is reflected in the torque output from the motor when the accelerator is off. It can be given to the driver.
JP 2005-51886 A

  In general, in the above-described vehicle, when the vehicle is stopped even when a torque based on a driver's accelerator operation amount is output from the motor during climbing, current concentrates on a specific phase of each phase coil of the motor. Since the temperature may reach high temperature, the torque output from the motor is reduced and the vehicle is intentionally moved backward to eliminate the concentrated current, and then the torque from the motor is increased to advance the vehicle. Torque reduction / increase control is executed to suppress overheating of the motor. In such torque reduction / increase control, the vehicle behaves differently from the normal behavior on an uphill road, and the occupant may feel uncomfortable. Therefore, it is hoped that both suppression of motor overheating and reduction of occupant discomfort will be achieved. It is rare. As a method of achieving both reduction of motor overheating and reduction of driver discomfort in torque reduction / increase control, the lower limit value of torque when reducing torque from the motor increases as the slope of the slope increases. It is conceivable to reduce the acceleration sensation when descending backwards by setting this, but the torque from the motor decreases with a relatively high torque when the slope of the slope is relatively large. Overheating may not be properly suppressed.

  A vehicle and a control method thereof according to the present invention are mainly intended to suppress overheating of an electric motor and reduce a sense of incongruity of an occupant.

  The vehicle of the present invention employs the following means in order to achieve the main object described above.

The vehicle of the present invention
A vehicle equipped with an electric motor capable of outputting power to an axle,
A slope detecting means for detecting the road slope;
Target torque setting means for setting a target torque to be output from the electric motor based on an accelerator operation amount;
Lower limit torque setting means for setting a lower limit torque that is a lower limit value of torque output from the electric motor in such a manner that the detected road surface gradient tends to increase as the climb gradient increases.
Even if the set target torque is output from the electric motor during climbing, the set target torque is greater than or equal to the first torque when a predetermined torque decrease / increase condition is satisfied with the vehicle substantially stopped. The torque output from the motor is reduced to reach a second torque smaller than the first torque, and the motor is controlled to increase to the set target torque after reaching the second torque, When the set target torque is less than the first torque, target torque output control is performed to control the motor so that the set target torque is output from the motor over a predetermined time, and the target torque is executed. After the output control is executed, the torque output from the electric motor decreases until reaching the set lower limit torque, and before the lower limit torque is reached. And stop control means for controlling said electric motor so as to increase to the set target torque,
It is a summary to provide.

  In the vehicle according to the present invention, when the predetermined torque decrease / increase condition is satisfied in a state where the vehicle is substantially stopped even when the target torque based on the accelerator operation amount is output from the electric motor during climbing, the target torque is the first torque. When the torque is equal to or greater than the torque, the motor is controlled so that the torque output from the motor decreases to a second torque smaller than the first torque and increases to the target torque after reaching the second torque. Since the torque output from the electric motor is reduced to reach the second torque, the vehicle slides down the uphill road. Thereby, since the state where the electric current concentrates on the specific phase of each phase coil of an electric motor is eased, overheating of an electric motor can be suppressed. Then, when the target torque is less than the first torque, target torque output control is performed to control the motor so that the target torque is output from the motor over a predetermined time, and after the target torque output control is performed, the target torque is output from the motor. The motor is controlled so that the torque increases until the lower limit torque, which tends to increase as the road surface gradient increases, and increases to the target torque set after reaching the lower limit torque. Since the target torque output control is executed for a predetermined time, it is possible to suppress the downhill road from slipping down during the predetermined time, and to reduce the passenger's uncomfortable feeling due to the downhill. In addition, after executing the target torque output control for a predetermined time, the torque output from the electric motor decreases until reaching the lower limit torque that tends to increase as the road surface gradient increases, so that the vehicle moves up the slope. The state where current is concentrated on a specific phase of each phase coil of the motor is mitigated and overheating of the motor can be suppressed, and the lower limit torque tends to increase as the road gradient increases Therefore, it is possible to alleviate the feeling of acceleration when the vehicle slides down the uphill road, and to reduce the discomfort of the passenger. Thereby, while overheating of an electric motor can be suppressed, a passenger | crew's discomfort can be reduced. Furthermore, after the torque output from the motor is reduced, the torque output from the motor is increased to the target torque, so that when the accelerator operation amount increases and the drive request increases, the drive request is quickly responded. Can do. Here, the “state where the vehicle is substantially stopped” includes a state where the vehicle speed is equal to or lower than a predetermined vehicle speed (for example, 2 km / hour) at which it can be determined that the vehicle is substantially stopped. The “first torque” should be resolved quickly by the current being concentrated on a specific phase of each phase coil of the motor when the torque is output from the motor when the vehicle is substantially stopped. Torque that can be determined as such. Further, the “second torque” may be such that when torque is output from the electric motor while the vehicle is substantially stopped, a state where current is concentrated on a specific phase of each phase coil of the electric motor may be continued. Torque that can be determined as such.

  In such a vehicle of the present invention, the lower limit torque setting means may be means for setting the lower limit torque as a torque not less than the second torque and less than the first torque.

  In the vehicle according to the present invention, the second torque may be a torque set to have a tendency to increase as the detected road surface gradient increases to an ascending gradient. In this way, even when the target torque is equal to or higher than the first torque, it is possible to alleviate the feeling of acceleration when the vehicle slides down the uphill road, and to reduce the occupant's discomfort.

  Further, in the vehicle according to the present invention, the internal combustion engine, a generator capable of inputting / outputting power, a drive shaft connected to an axle, an output shaft of the internal combustion engine, and a rotation shaft of the generator are connected to three axes. And three-shaft power input / output means for inputting / outputting power to / from the remaining shafts based on power input / output to / from any two of the three shafts, and exchange of power with the generator and the motor. The electric motor may be capable of inputting / outputting power to / from the drive shaft. If it carries out like this, also in a vehicle provided with an internal-combustion engine and an electric motor, overheating of an electric motor can be controlled and a feeling of strangeness of a crew member can be reduced.

The vehicle control method of the present invention includes:
There is a method for controlling a vehicle equipped with an electric motor capable of outputting power to an axle,
Even when a target torque based on the accelerator operation amount is output from the electric motor during climbing, the target torque is equal to or greater than the first torque when a predetermined torque decrease / increase condition is satisfied with the vehicle substantially stopped. Sometimes, the motor is controlled so that the torque output from the electric motor decreases to a second torque smaller than the first torque and reaches the second torque, and then increases to the target torque. When the torque is less than the first torque, target torque output control is performed to control the motor so that the target torque is output from the motor over a predetermined time, and the target torque output control is performed and then output from the motor. After the torque reaches a lower limit torque that tends to increase as the slope of the road becomes larger And summarized in that to control the electric motor so as to increase to the target torque.

  In the vehicle control method according to the present invention, when a predetermined torque decrease condition is satisfied in a state where the vehicle is substantially stopped even when the target torque based on the accelerator operation amount is output from the electric motor during climbing, the target torque is satisfied. When the torque is equal to or greater than the first torque, the motor is controlled so that the torque output from the motor decreases to the second torque smaller than the first torque and increases to the target torque after reaching the second torque. Since the torque output from the electric motor is reduced to reach the second torque, the vehicle slides down the uphill road. Thereby, the state where the current is concentrated on a specific phase of each phase coil of the electric motor is alleviated, and overheating of the electric motor can be suppressed. Then, when the target torque is less than the first torque, target torque output control is performed to control the motor so that the target torque is output from the motor over a predetermined time, and after the target torque output control is performed, the target torque is output from the motor. The motor is controlled so that the torque increases until the lower limit torque, which tends to increase as the road surface gradient increases, and increases to the target torque set after reaching the lower limit torque. Since the target torque output control is executed for a predetermined time, it is possible to suppress the downhill road from slipping down during the predetermined time, and to reduce the passenger's uncomfortable feeling due to the downhill. In addition, after executing the target torque output control for a predetermined time, the torque output from the electric motor decreases until reaching the lower limit torque that tends to increase as the road surface gradient increases, so that the vehicle moves up the slope. The state where current is concentrated on a specific phase of each phase coil of the motor is mitigated and overheating of the motor can be suppressed, and the lower limit torque tends to increase as the road gradient increases Therefore, it is possible to alleviate the feeling of acceleration when the vehicle slides down the uphill road, and to reduce the discomfort of the passenger. Thereby, while overheating of an electric motor can be suppressed, a passenger | crew's discomfort can be reduced. In addition, after the torque output from the motor is reduced, the torque output from the motor is increased to the target torque, so that when the drive request increases and the accelerator operation amount increases, the drive request is quickly responded. Can do. Here, the “state where the vehicle is substantially stopped” includes a state where the vehicle speed is equal to or lower than a predetermined vehicle speed (for example, 2 km / hour) at which it can be determined that the vehicle is substantially stopped. The “first torque” should be resolved quickly by the current being concentrated on a specific phase of each phase coil of the motor when the torque is output from the motor when the vehicle is substantially stopped. Torque that can be determined as such. Further, the “second torque” may be such that when torque is output from the electric motor while the vehicle is substantially stopped, a state where current is concentrated on a specific phase of each phase coil of the electric motor may be continued. Torque that can be determined as such.

  Next, the best mode for carrying out the present invention will be described using examples.

  FIG. 1 is a configuration diagram showing an outline of a configuration of an electric vehicle 20 as an embodiment of the present invention. As shown in the drawing, the electric vehicle 20 of the embodiment includes a motor 22 that can input and output power to a drive shaft 32 connected to drive wheels 30 a and 30 b via a differential gear 31, and an inverter 24 that drives the motor 22. A battery 26 as a secondary battery that exchanges electric power with the motor 22 and an electronic control unit 40 that controls the entire vehicle.

  The motor 22 is configured as a PM type synchronous generator motor including a rotor having a permanent magnet attached to the outer peripheral surface and a stator around which a three-phase coil is wound. The inverter 24 is configured by six switching elements, converts the DC power supplied from the battery 26 into pseudo three-phase AC power, and supplies the pseudo three-phase AC power to the motor 22.

  The electronic control unit 40 is configured as a microprocessor centered on a CPU, and includes a ROM 44 for storing a processing program, a RAM 46 for temporarily storing data, and an input / output port (not shown) in addition to the CPU 42. The electronic control unit 40 includes a rotational position θm from the rotational position detection sensor 23 that detects the rotational position of the motor 22, a battery temperature from a temperature sensor (not shown) that detects the temperature of the battery 26, an ignition signal from the ignition switch 50, A shift position SP from the shift position sensor 52 that detects the operation position of the shift lever 51, an accelerator opening Acc from the accelerator pedal position sensor 54 that detects the depression amount of the accelerator pedal 53, and a brake that detects the depression amount of the brake pedal 55 The brake pedal position BP from the pedal position sensor 56, the vehicle speed V from the vehicle speed sensor 58 that detects the vehicle speed, the road surface gradient θ from the gradient sensor 60 that detects the road surface gradient, and the like are input via the input port. From the electronic control unit 40, a switching control signal to the switching element of the inverter 24 for driving and controlling the motor 22 is output via an output port.

  Next, the operation of the electric vehicle 20 of the embodiment configured as described above, particularly when the forward driving force output from the vehicle on the uphill road is balanced with the downhill road acting on the vehicle, etc. The operation when the vehicle is substantially stopped despite the fact that torque is being output from will be described. FIG. 2 is a flowchart illustrating an example of a motor control routine at the time of stopping uphill executed by the electronic control unit 40. In this routine, the vehicle is substantially stopped while the torque based on the accelerator opening degree Acc and the vehicle speed V is output from the motor 22 during climbing, and the torque output from the motor 22 is the motor 22. It is assumed that it is executed when a state of a predetermined torque T2 or more that can be determined that a current of a predetermined value or more is flowing in a specific phase among the respective phase coils continues for a predetermined time or more. Here, “the vehicle is substantially stopped” means that the absolute value of the vehicle speed V from the vehicle speed sensor 58 is equal to or less than a stop vehicle speed Vst (for example, 2 km / hour) at which it can be determined that the vehicle is substantially stopped. The state was said.

  When the uphill stop motor control routine is executed, the CPU 42 of the electronic control unit 40 inputs the accelerator opening Acc from the accelerator pedal position sensor 54 and the vehicle speed V from the vehicle speed sensor 58 (step S100). Based on the opening degree Acc and the vehicle speed V, a process of setting a required torque Td * to be output to the drive shaft 32 as a torque required for the vehicle is executed (step S110). In the embodiment, the required torque Td * is determined in advance by storing the relationship between the accelerator opening Acc, the vehicle speed V, and the required torque Td * in the ROM 44 as a required torque setting map. , The corresponding required torque Td * is derived from the stored map and set. FIG. 3 shows an example of the required torque setting map.

  When the required torque Td * is set, the set required torque Td * is compared with the threshold value T1 (step S120). The threshold value T1 is such that when a torque is output from the motor 22 in a state where the absolute value of the vehicle speed V is equal to or less than the stop vehicle speed Vst, the current concentrates on a specific phase of each phase coil of the motor 22 so The torque obtained by analysis or experiment is set as a torque that can be determined that 24 immediately reaches a high temperature.

  When the required torque Td * is equal to or greater than the threshold value T1, it is determined that the motor 22 or the inverter 24 may immediately reach a high temperature, the value 0 is set in the flag F (step S130), and the lower limit torque Tmin is set to a predetermined value. The torque T2 is set (steps S140 and S150), and the torque obtained by subtracting the torque change amount R from the already set torque command Tm * (previous Tm *) of the motor 22 and the lower limit torque Tmin are used as the torque. The switching control of the switching element of the inverter 24 is executed so that the motor 22 is driven by the torque command Tm * while being set as the command Tm * (step S160), and an end condition for ending this routine is satisfied (step S170). ), Until the set torque command Tm * reaches the lower limit torque Tmin (step S180) Processing of step S140~S180 repeated. In the process of step S130, the flag F is set to a value of 1 when it is determined in the process of step S120 that the required torque Td * is less than the threshold value T1, and it is determined that the required torque Td * is greater than or equal to the value T1. The flag is set to a value of 0 when In the process of step S160, the torque change amount R1 is set empirically as a change amount that does not cause the driver to feel uncomfortable due to a change in torque, and this routine is executed to execute the process of step S160 first. It is assumed that the required torque Td * is set as the previous Tm *. Further, in the process of step S170, the end condition is that the change amount of the accelerator opening Acc is equal to or greater than a predetermined change amount that can be determined that the driver's drive request has changed, and the rotation position for detecting the rotation position of the motor 22. It can be determined that the absolute value of the rotational speed Nm of the motor 22 calculated based on the rotational position θm from the detection sensor 23 is not in a state where current is concentrated in a specific phase of each phase coil of the motor 22. What is satisfied when any one of the conditions equal to or higher than the predetermined rotation speed Nref is satisfied may be satisfied when another condition is satisfied. By such control, the torque output from the motor 22 gradually decreases from the required torque Td * toward the lower limit torque Tmin. In a state in which the required torque Td * is output from the motor 22, the vehicle is substantially stopped on the slope, and therefore, the vehicle slides down (retreats) on the slope by reducing the torque output from the motor 22. The reason why the vehicle is moved backward is based on the following reason. When the vehicle is substantially stopped despite the torque based on the accelerator opening Acc being output from the motor 22 when climbing, it is considered that the current is concentrated in a specific phase of each phase coil of the motor 22. . If such current concentration continues, the motor 22 and the inverter 24 may reach a high temperature. Therefore, the state where the current is concentrated on a specific phase of the motor 22 is eliminated by moving the vehicle backward and rotating the motor 22. This is to prevent the motor 22 and the inverter 24 from reaching a high temperature.

  When the above termination condition is satisfied while the torque output from the motor 22 is decreasing, that is, the state where the current is concentrated on a specific phase of the motor 22 is eliminated, or the driver's drive request is large. When this happens (step S170), the uphill stop motor control routine is terminated. Thus, after the uphill stop motor control routine is completed, the control shifts to other control (not shown), for example, control of traveling while outputting the required torque Td * based on the accelerator opening Acc and the vehicle speed V from the motor 22. By such control, when the state where the current concentrates on a specific phase of the motor 22 is resolved or when the driving demand of the driver becomes large, it is possible to quickly shift to another control.

  When the torque output from the motor 22 decreases to reach the lower limit torque Tmin without satisfying the end condition (steps S170 and S180), the state where the current concentrates on a specific phase of the motor 22 has not been resolved. As described above, it is determined that the torque Tm * output from the motor 22 should not be reduced, and the torque change amount R added to the torque command Tm * (previous Tm *) of the motor 22 that has already been set and the required torque Td * Is set as the torque command Tm *, and the motor 22 is driven by the torque command Tm * (step S190), and the above-mentioned end condition is satisfied (step S200), or the set torque command Tm Until * reaches the required torque Td * (step S210), the processes of steps S190 to S210 are repeated. By such control, the torque output from the motor 22 gradually increases, so that the backward movement of the vehicle is suppressed, and when the accelerator pedal 53 is next depressed and the driver's driving demand increases, a quick response is made. be able to.

  When the above-described termination condition is satisfied while the torque output from the motor 22 is increasing (step S200), the uphill stop motor control routine is terminated, and other control (not shown), for example, accelerator opening is performed. The process shifts to control for traveling while outputting the required torque Td * based on the degree Acc and the vehicle speed V from the motor 22. By such control, it is possible to quickly shift to another control.

  When the torque from the motor 22 increases and reaches the required torque Td * without satisfying the termination condition (steps S200 and S210), the state where current concentrates on a specific phase of the motor 22 has not been resolved, but more It is determined that the torque Tm * output from the motor 22 should not be increased, and the process returns to the process of step S140 to execute the process of decreasing the torque output from the motor 22 again until the end condition is satisfied (step S140). S170, S200) and steps S140 to S210 are repeated. FIG. 4 is an explanatory diagram illustrating an example of a time change of the torque command Tm * of the motor 22 when the required torque Td * is equal to or greater than the threshold T1. The torque command Tm * decreases from the required torque Td * to the predetermined torque T2 (time t1 to t2) when the execution of the uphill stop motor control routine is started (time t1), and then the predetermined torque T2 to the required torque Td. * (Time t2 to t3), and the torque command Tm * is repeatedly increased and decreased until the above-described end condition is satisfied. Since the motor 22 is controlled using the torque command Tm *, when the required torque Td * is equal to or greater than the threshold value T1, the torque output from the motor 22 is immediately increased and the vehicle is repeatedly lowered and stopped. Thus, although the occupant's uncomfortable feeling cannot be reduced, it is possible to prevent the current from concentrating on a specific phase among the phase coils of the motor 22 output from the motor 22 and to prevent overheating of the motor 22 and the inverter 24. Can be suppressed.

  When the required torque Td * is less than the threshold value T1 (step S120), it is determined that there is no problem with eliminating the state where the current is concentrated immediately because the torque output from the motor 22 is relatively small. Is set to 1 (step S220), the required torque Td * is set to the torque command Tm * of the motor 22, and the motor 22 is driven by the torque command Tm * (step S230), so that the above-described termination condition is satisfied. (Step S240), until the predetermined time tref elapses after the start of the uphill stop motor control routine (step S250), the processes of steps S220 to S250 are repeated and finished before the predetermined time tref elapses. When the condition is satisfied (step S240), the motor control routine at the time of climbing stop is terminated. Here, the predetermined time tref is obtained and set by experiment or analysis as a time that allows the temperature rise of the motor 22 or the inverter 24 to be allowed when a torque slightly smaller than the threshold value T1 is output from the motor 22 as torque. For example, it is set to about several seconds. By such control, the motor 22 is driven by the torque command Tm * set to the required torque Td *, so that the vehicle is maintained in a stopped state, and immediately from the motor 22 when the required torque Td * is equal to or greater than the threshold value T1. The occupant's uncomfortable feeling can be reduced as compared with the case where the torque of the vehicle is reduced.

  When the predetermined time tref has elapsed with the required torque Td * being output from the motor 22 without the termination condition being satisfied (steps S240 and S250), the flag F is 1 (step S140). A road surface gradient θ is input from the gradient sensor 60 (S260), a lower limit torque Tmin is set based on the input road surface gradient θ (step S270), and the torque command Tm * (previous Tm *) of the motor 22 that has already been set. ) From which the torque change amount R is subtracted and the lower limit torque Tmin is set as the torque command Tm * and the motor 22 is driven by the torque command Tm * (step S160), and the above-mentioned termination condition is satisfied. Until the set torque command Tm * reaches the lower limit torque Tmin (step S180). ), The processing of steps S140, S260, S270, S160 to S180 is repeated, and when the above-mentioned end condition is satisfied while the torque output from the motor 22 is being reduced (steps S170 and S180), the climbing stop is performed. The motor control routine is terminated, and the process proceeds to the other control described above. In the process of step S270, the lower limit torque Tmin is set so as to increase downward from the predetermined torque T2 to a convex curve as the road surface gradient θ increases to an upward gradient as shown in FIG. This is because when the lower limit value of the torque output from the motor 22 is constant regardless of the road surface gradient, the greater the road surface gradient θ is, the higher the climb gradient, the more rearward the passenger feels when the vehicle slides down. This is because the feeling of acceleration is increased, but the acceleration feeling can be reduced by setting the lower limit torque Tmin to be larger as the road surface gradient θ increases to the climbing gradient. Therefore, by such control, it is possible to reduce the feeling of acceleration in the rear when the torque output from the motor 22 is reduced, and it is possible to reduce the sense of incongruity of the occupant when sliding down.

  When the torque output from the motor 22 reaches the lower limit torque Tmin without satisfying the end condition (steps S170 and S180), the above end condition is satisfied, or the set torque command Tm * is set to the required torque Td *. The torque command Tm * (previous Tm *) of the motor 22 is set so as to increase with the change amount R toward the required torque Td * until the torque output from the motor 22 is increased (steps S190 to S210). With such control, when the accelerator pedal 53 is next depressed and the driver's drive request becomes large, a quick response can be made.

  When the torque from the motor M22 increases and reaches the required torque Td * without satisfying the end condition (steps S200 and S210), the process returns to the process of step S140, and the process of decreasing the torque output from the motor 22 again. The process of steps S140, S260, S270, and S160 to S210 is repeated until the end condition is satisfied (steps S170 and S200). FIG. 6 is an explanatory diagram showing an example of a time change of the torque command Tm * of the motor 22 when the required torque Td * is less than the threshold value T1. In the figure, an example of the time change of the torque command Tm * when the required torque Td * is less than the threshold value T1 is indicated by a solid line, and an example of the time change of the torque command Tm * when the required torque Td * is equal to or greater than the threshold value T1 is a broken line. Is shown. The torque command Tm * is set to the required torque Td * (time t4) until the predetermined time tref elapses when the uphill stop motor control routine starts (time t1), and then the lower limit based on the road surface gradient θ. The torque decreases to the torque Tmin (time t4 to t5), increases to the required torque Td * when the lower limit torque Tmin is reached (time t5 to t6), and repeats such decrease and increase until the above termination condition is satisfied. . By controlling the motor 22 with such a torque command Tm *, the vehicle slides down from the stopped state and stops again. Therefore, it is possible to suppress the current from being concentrated on a specific phase among the phase coils of the motor 22. Further, overheating of the motor 22 and the inverter 24 can be suppressed. In addition, since the torque lower limit Tmin when decreasing the torque of the motor 22 is set so as to increase as the road surface gradient θ increases, the feeling of acceleration in the rearward direction when the vehicle slides is reduced, and the passenger's discomfort is reduced. . Therefore, overheating of the motor 22 and the inverter 24 can be suppressed, and a passenger's discomfort can be reduced.

  According to the electric vehicle 20 of the embodiment described above, when the required torque Td * is equal to or greater than the threshold value T1, the torque output from the motor 22 is decreased until reaching the predetermined torque T2. The state where the current is concentrated can be alleviated, and overheating of the motor 22 can be suppressed. Further, when the required torque Td * is less than the threshold value T1, the motor 22 is controlled so that the required torque Td * is output from the motor 22 over a predetermined time tref, so that the sliding is suppressed and the passenger feels uncomfortable. Can be reduced. Then, after the predetermined time tref has elapsed, the torque output from the motor 22 is decreased until reaching the lower limit torque Tmin, so that the vehicle slides down the uphill road and the motor 22 rotates to rotate each phase coil of the motor 22. The state where current is concentrated in a specific phase is alleviated, and overheating of the motor 22 can be suppressed. Further, since the lower limit torque Tmin is set so as to increase as the road surface gradient θ increases, the feeling of acceleration can be mitigated when the vehicle moves down the uphill road, and the occupant's uncomfortable feeling can be reduced. Therefore, it is possible to suppress overheating of the motor 22 and reduce the occupant's uncomfortable feeling. Further, after the torque output from the motor 22 is reduced in this way, the torque output from the motor 22 is increased to the required torque Td *, so that the next time the accelerator pedal 53 is depressed and the drive request increases. You can respond quickly.

  In the electric vehicle 20 of the embodiment, in the process of step S270, as shown in FIG. 5, the lower limit torque Tmin is set so as to increase in a downward convex curve as the road surface gradient θ increases to an upward gradient. The lower limit torque Tmin may be set so as to increase as the road surface gradient θ increases, and the lower limit torque Tmin may increase stepwise with respect to the road surface gradient θ, or increase linearly. It is good.

  In the electric vehicle 20 of the embodiment, the torque output from the motor 22 is increased to the required torque Td * set in the process of step S110 in the process of step S190. The accelerator opening Acc is input, the required torque Td * when the vehicle speed V is 0 at the current accelerator opening Acc is obtained using the required torque setting map of FIG. 3, and the torque output from the motor 22 is calculated. The required torque Td * thus obtained may be increased.

  In the electric vehicle 20 of the embodiment, the lower limit torque Tmin is set to the predetermined torque T2 in the process of step S150, but the lower limit torque Tmin may be set to increase as the road surface gradient θ increases. By so doing, it is possible to suppress a feeling of acceleration backward even when the required torque Td * is equal to or greater than the threshold value T1.

  In the electric vehicle 20 of the embodiment, the required torque Td * is set based on the accelerator opening Acc and the vehicle speed V in the process of step S110, but may be set using only the accelerator opening Acc. Good.

  In the electric vehicle 20 of the embodiment, the lower limit torque Tmin is set to the predetermined torque T2 in the process of step S150, but any torque may be set as long as it is less than the threshold T1, for example, less than the predetermined torque T2. The torque may be set, or the torque may be set to be less than the threshold value T1 and greater than the predetermined torque T2. In the process of step S270, the lower limit torque Tmin is set to a torque equal to or higher than the predetermined torque T2, but may be set to a torque lower than the predetermined torque T2.

  In the electric vehicle 20 of the embodiment, the motor control routine at the time of climbing stop is substantially stopped although the torque based on the accelerator opening Acc and the vehicle speed V is output from the motor 22 at the time of climbing, and A state in which the torque to be output from the motor 22 is equal to or higher than a predetermined torque T2 at which a current of a predetermined value or more is flowing in a specific phase of each phase coil of the motor 22 continues for a predetermined time or longer. The inverter 24 is executed when there is a possibility of reaching a high temperature, but instead of or in addition to the condition that the torque to be output from the motor 22 is equal to or higher than the predetermined torque T2, the temperature of the motor 22 The climbing stop motor control routine is executed when the temperature of the inverter 24 is equal to or higher than a predetermined temperature at which it can be determined that the motor 22 or the inverter 24 reaches a high temperature. It may be.

  In the embodiment, the electric vehicle 20 including the motor 22 that can input and output power to the drive shaft 32 and the battery 26 that exchanges power with the motor 22 has been described, but in addition to the motor 22 and the battery 26, FIG. As illustrated in the electric vehicle 120 of the modified example, the engine 122 that outputs power using a hydrocarbon fuel such as gasoline or light oil, the motor 124 configured as a synchronous generator motor, the output of the drive shaft 32 and the engine 22. A planetary gear mechanism 126 in which a ring gear, a carrier, and a sun gear are connected to the shaft and the rotating shaft of the motor 124, respectively, and the battery 26 is configured to exchange power with the motors 22 and 124 via the inverter 24 and the inverter 128. The present invention may be applied to an electric vehicle 120 that is a hybrid vehicle.

  Moreover, it is not limited to what is applied to such an electric vehicle, It does not matter as forms of vehicles, such as a train other than a motor vehicle. Furthermore, it is good also as a form of the control method of such a vehicle.

  Here, the correspondence between the main elements of the embodiment and the main elements of the invention described in the column of means for solving the problems will be described. In the embodiment, the motor 22 corresponds to the “electric motor”, the gradient sensor 60 corresponds to the “gradient detection means”, and the requested torque Td * is set based on the accelerator opening Acc and the vehicle speed V. The electronic control unit 40 that executes the process of step S110 of the hour motor control routine corresponds to the “target torque setting means”, and sets the lower limit torque Tmin so that the road surface gradient θ increases as the climb gradient increases. The electronic control unit 40 that executes the processing of step S270 of the hour motor control routine corresponds to the “lower limit torque setting means”, and outputs torque based on the accelerator opening Acc and the vehicle speed V from the motor 22 when climbing up. Regardless, the vehicle is substantially stopped, and the torque to be output from the motor 22 is a predetermined value in a specific phase of each phase coil of the motor 22. When the state of the predetermined torque T2 or more that can be determined that the upper current is flowing continues for a predetermined time or more, and the required torque Td * is the threshold T1 or more, the torque output from the motor 22 is the predetermined torque T2. The torque command Tm * of the motor 22 is set so as to increase to the required torque Td * after reaching the predetermined torque T2, and the motor 22 is controlled with the set torque command Tm *. When the process of steps S120 to S210 of the motor control routine and the required torque Td * are less than the threshold value T1, the required torque Td * is set to the torque command Tm * of the motor 22 and set for the predetermined time tref. The process of steps S120 and S220 to S250 for controlling the motor 22 and the torque output from the motor 22 The torque command Tm * of the motor 22 is set so as to increase to the required torque Td * after reaching the lower limit torque Tmin after the torque reaches the set lower limit torque Tmin. The electronic control unit 40 that executes the processes of steps S140, S260, S270, and S160 to S210 to be controlled corresponds to the “stop time control means”. The engine 122 corresponds to an “internal combustion engine”, the motor 124 corresponds to a “generator”, the planetary gear mechanism 126 corresponds to a “three-shaft power input / output unit”, and the battery 26 corresponds to a power storage unit. Here, the “motor” is not limited to the motor 22 configured as a synchronous generator motor, and may be any type of motor as long as it can output power to the axle, such as an induction motor. Absent. The “gradient detection means” is not limited to the gradient sensor 60, and any means can be used as long as it detects a road surface gradient. The “target torque setting means” is not limited to the one that sets the required torque Td * based on the accelerator opening Acc and the vehicle speed V, but the target torque that should be output from the electric motor based on the accelerator operation amount. Anything can be used as long as it is set. The “lower limit torque setting means” is not limited to the setting of the lower limit torque Tmin so that the road surface gradient θ increases as the climbing gradient increases, and tends to increase as the detected road surface gradient increases as the climbing gradient. Any lower limit torque that is the lower limit value of the torque output from the electric motor may be set. The “stop-time control means” is not limited to the electronic control unit 40, and may be configured by a plurality of electronic control units. Further, as the “control means at the time of stop”, the vehicle is substantially stopped and output from the motor 22 even though the torque based on the accelerator opening Acc and the vehicle speed V is output from the motor 22 when climbing up. When the torque to be to be exceeded is a predetermined torque T2 or more that can be determined that a current of a predetermined value or more is flowing in a specific phase of each phase coil of the motor 22, the required torque Td * Is equal to or greater than the threshold value T1, the motor 22 is controlled such that the torque output from the motor 22 decreases until reaching the predetermined torque T2, reaches the predetermined torque T2, and then increases to the required torque Td *. When it is less than the threshold value T1, the motor 22 is controlled so that the required torque Td * is output from the motor 22 for a predetermined time tref, and then output from the motor 22. The motor 22 is not limited to controlling the motor 22 so as to decrease to the set lower limit torque Tmin and increase to the required torque Td * after reaching the lower limit torque Tmin. Torque output from the motor when the set target torque is equal to or greater than the first torque when the predetermined torque decrease / increase condition is satisfied with the vehicle substantially stopped even if the set target torque is output. The motor is controlled to decrease to reach the second torque smaller than the first torque and increase to the set target torque after reaching the second torque, and is predetermined when the set target torque is less than the first torque The target torque output control for controlling the electric motor is executed so that the set target torque is output from the electric motor over time and the target torque output control is performed. As long as the motor is controlled so as to decrease the torque output from the motor after reaching the set lower limit torque and increase it to the set target torque after reaching the lower limit torque, any method may be used. Absent. The “internal combustion engine” is not limited to an internal combustion engine that outputs power using a hydrocarbon fuel such as gasoline or light oil, and may be any type of internal combustion engine such as a hydrogen engine. The “generator” is not limited to the motor 124 configured as a synchronous generator motor, and may be any type of generator as long as it can input and output power, such as an induction motor. The “three-axis power input / output means” is not limited to the planetary gear mechanism 126, such as one using a double pinion planetary gear mechanism, a combination of a plurality of planetary gear mechanisms, or a differential gear. Connected to three axes of a drive shaft coupled to an axle, an output shaft of an internal combustion engine, and a rotating shaft of a generator, such as one having a differential action different from that of a planetary gear, and any two of the three axes As long as the power is input / output to / from the remaining shafts based on the input / output power, any configuration may be used. The “storage means” is not limited to the battery 26 as a secondary battery, and may be anything as long as it can exchange power with a generator and an electric motor such as a capacitor. The correspondence between the main elements of the embodiment and the main elements of the invention described in the column of means for solving the problem is the same as that of the embodiment described in the column of means for solving the problem. It is an example for specifically explaining the best mode for doing so, and does not limit the elements of the invention described in the column of means for solving the problem. That is, the interpretation of the invention described in the column of means for solving the problems should be made based on the description of the column, and the examples are those of the invention described in the column of means for solving the problems. It is only a specific example.

  The best mode for carrying out the present invention has been described with reference to the embodiments. However, the present invention is not limited to these embodiments, and various modifications can be made without departing from the gist of the present invention. Of course, it can be implemented in the form.

  The present invention can be used in the vehicle manufacturing industry.

It is a block diagram which shows the outline of a structure of the electric vehicle 20 as one Example of this invention. It is a flowchart which shows an example of the motor control routine at the time of an uphill stop performed by the electronic control unit 40 of an Example. It is explanatory drawing which shows an example of the map for request | requirement torque setting. It is explanatory drawing which shows an example of the time change of torque command Tm * of the motor 22 when request | requirement torque Td * is more than threshold value T1. It is explanatory drawing which shows an example of the map for a minimum torque setting. It is explanatory drawing which shows an example of the time change of torque command Tm * of the motor 22 when request torque Td * is less than threshold value T1. FIG. 11 is a configuration diagram showing an outline of a configuration of a hybrid vehicle 120 according to a modification.

Explanation of symbols

  20,120 Electric vehicle, 22,124 motor, 23 rotational position detection sensor, 24, 128 inverter, 26 battery, 30a, 30b drive wheel, 31 differential gear, 32 drive shaft, 40 electronic control unit, 42 CPU, 44 ROM, 46 RAM, 50 Ignition switch, 51 Shift lever, 52 Shift position sensor, 53 Accel pedal, 54 Accel pedal position sensor, 55 Brake pedal, 56 Brake pedal position sensor, 58 Vehicle speed sensor, 60 Gradient sensor, 122 Engine, 126 Planetary gear mechanism.

Claims (5)

A vehicle equipped with an electric motor capable of outputting power to an axle,
A slope detecting means for detecting the road slope;
Target torque setting means for setting a target torque to be output from the electric motor based on an accelerator operation amount;
Lower limit torque setting means for setting a lower limit torque that is a lower limit value of torque output from the electric motor in such a manner that the detected road surface gradient tends to increase as the climb gradient increases.
Even when the set target torque is output from the electric motor during climbing, the set target torque is greater than or equal to the first torque when the predetermined torque decrease / increase condition is satisfied with the vehicle substantially stopped. The torque output from the motor is reduced to reach a second torque smaller than the first torque, and the motor is controlled to increase to the set target torque after reaching the second torque, When the set target torque is less than the first torque, target torque output control is performed to control the motor so that the set target torque is output from the motor over a predetermined time, and the target torque is executed. After the output control is executed, the torque output from the electric motor decreases until reaching the set lower limit torque, and before the lower limit torque is reached. And stop control means for controlling said electric motor so as to increase to the set target torque,
A vehicle comprising: The vehicle according to claim 1,
The lower limit torque setting means is means for setting the lower limit torque as a torque not less than the second torque and less than the first torque. The vehicle according to claim 1 or 2,
The second torque is a torque set such that the detected road surface gradient becomes larger as the climb gradient increases. A vehicle according to any one of claims 1 to 3,
An internal combustion engine;
A generator capable of inputting and outputting power;
It is connected to three shafts, that is, a drive shaft coupled to an axle, an output shaft of the internal combustion engine, and a rotating shaft of the generator, and the remaining power is determined based on power input / output to / from any two of the three shafts. 3-axis power input / output means for inputting / outputting power to the shaft;
Power storage means capable of exchanging electric power with the generator and the motor;
With
The electric motor can input and output power to the drive shaft. There is a method for controlling a vehicle equipped with an electric motor capable of outputting power to an axle,
Even when a target torque based on the accelerator operation amount is output from the electric motor during climbing, the target torque is equal to or greater than the first torque when a predetermined torque decrease / increase condition is satisfied with the vehicle substantially stopped. Sometimes, the motor is controlled so that the torque output from the electric motor decreases to a second torque smaller than the first torque, reaches the second torque and then increases to the target torque, and the target torque is When the torque is less than the first torque, target torque output control is performed to control the motor so that the target torque is output from the motor over a predetermined time, and the target torque output control is performed and then output from the motor. After the torque reaches a lower limit torque that tends to increase as the slope of the road becomes larger The vehicle control method of controlling the electric motor so as to increase to the target torque.

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