JP2005312187A - Automobile - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enhance the travelling performance while suppressing the excessive heating of a motor. <P>SOLUTION: When a road gradient is rising at or over a specified angle and slips occur in front wheels 63a and 63b, this automobile reduces the torque to be output to a front wheel 64 and does not limit the torque of a motor MG3 until the temperature of the motor MG3 connected to a rear axle 67 goes higher than a threshold T2ref under specified conditions in case that goes higher than a threshold T1ref when having increased the torque to be output to the rear axle 67, so that the torque to be output may be maintained according to the treading quantity of an accelerator pedal 83. Hereby, it can quickly escape from a slope of low μ, and in case that the temperature of the motor MG3 goes higher than the threshold T2ref, it starts the limitation of the torque of the motor MG3, so it can suppress the excessive heat generation. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an automobile, and more particularly, to an automobile capable of outputting power to a first wheel and a second wheel.

Conventionally, as this type of vehicle, a four-wheel drive type electric vehicle including an engine and a motor generator connected to a front wheel via a transmission and a rear motor generator connected to a rear wheel has been proposed ( Patent Document 1). In this automobile, when the front wheel slips, the torque is output from the rear motor generator, that is, the four-wheel drive is performed, so that the slip can be eliminated and the running performance of the vehicle can be secured. In the motor generator and the rear motor generator, when the temperature rises above a certain threshold, the output torque is limited to protect the parts.
JP 2001-186603 A

  In the above-described automobile, the torque output for protecting the parts is limited with respect to the temperature rise of the motor generator. However, it may not be preferable to always perform such limitation. The torque limit due to the temperature rise of the motor generator is usually set with a certain margin, and even if the temperature rise exceeds the threshold value, it does not immediately affect the durability. Therefore, depending on the running state of the vehicle, it may be better to give priority to the running performance of the vehicle than to limit the torque of the motor generator. On the other hand, if the torque to be output indefinitely is not limited with respect to the temperature rise of the motor generator, the high temperature state may continue to cause a problem in the motor generator.

  One object of the automobile of the present invention is to further improve the running performance of the vehicle while suppressing excessive heat generation of the electric motor. Another object of the automobile of the present invention is to further improve the running performance on the slope while suppressing excessive heat generation of the electric motor. Furthermore, an object of the automobile of the present invention is to further improve the running performance against slip while suppressing excessive heat generation of the electric motor.

  The automobile of the present invention has taken the following means in order to achieve at least a part of the above-mentioned object.

The automobile of the present invention
An automobile capable of outputting power to the first wheel and the second wheel,
Power output means capable of outputting power to the first wheel;
An electric motor capable of outputting power to the second wheel;
Drive control means for driving and controlling the power output means and the electric motor so that a required drive force as a required value of the drive force for running the vehicle is output;
Temperature detecting means for detecting the temperature of an electric drive system including the electric motor;
Driving force limiting means for limiting the driving force output from the electric motor based on the detected temperature of the electric drive system;
And a restriction release relaxation means for executing restriction release relaxation control for releasing or relaxing the restriction of the driving force output from the electric motor by the driving force restriction means when the vehicle reaches a predetermined traveling state. .

  In the automobile according to the present invention, power is output to the second wheel and the power output means capable of outputting power to the first wheel so that the required driving force as the required value of the driving force for driving the vehicle is output. The drive power output from the motor is limited based on the temperature of the electric drive system including the motor, and the drive power output from the motor is limited when the vehicle reaches a predetermined traveling state. Release or relax. Therefore, it is possible to further improve the running performance for the predetermined running state of the vehicle. Further, since the restriction or relaxation of the driving force restriction is performed only when the vehicle reaches a predetermined traveling state, excessive heat generation of the electric motor can be suppressed.

  In such an automobile of the present invention, the driving force limiting means is a means for limiting the driving force output from the electric motor when the detected temperature of the electric drive system is higher than a first threshold, and the restriction release The relaxation means may be means for executing the restriction release relaxation control when the detected temperature of the electric drive system is equal to or lower than a second threshold value that is larger than the first threshold value.

  In the automobile of the present invention, the restriction release mitigation means may be means for executing the restriction mitigation control when the road surface gradient is equal to or greater than a predetermined gradient as the climbing gradient in the predetermined traveling state. . If it carries out like this, running performance of a slope can be improved more, suppressing the excessive heat_generation | fever of an electric motor.

  Further, in the automobile of the present invention, when the slip occurs on the first wheel, the drive control means controls the power output means so that the generated slip is suppressed and responds to the required driving force. The restriction release relaxation means is a means for executing the restriction release relaxation control when the first wheel is slipping as the predetermined traveling state. It can also be. If it carries out like this, the driving | running | working performance with respect to the slip of a 1st wheel can be improved more, suppressing the excessive heat_generation | fever of an electric motor.

  The automobile according to the present invention further includes a cumulative execution number storage unit that stores a cumulative execution number of the restriction release relaxation control, and the restriction release relaxation unit includes the limit when the stored cumulative execution number is equal to or greater than a predetermined number. It may be a means that does not execute the release relaxation control. In this way, deterioration of the electric motor due to heat generation can be suppressed.

  In the automobile of the present invention, the restriction release relaxation means performs the restriction release relaxation control until a predetermined time elapses after the restriction release relaxation control is executed last time and / or until the vehicle travels a predetermined distance. It may be a means that is not executed. By doing so, it is possible to suppress the electric motor from being frequently in a high temperature state.

  In the vehicle of the present invention in which the driving force limiting means limits the driving force output from the electric motor when the temperature of the electric drive system is higher than the first threshold, the restriction release mitigating means includes the detected electric drive The restriction release relaxation control may be stopped when the system temperature is higher than the first threshold for a second predetermined time. If it carries out like this, generation | occurrence | production of the malfunction of the electric motor by continuing a high temperature state can be suppressed.

  In the vehicle of the present invention in which the driving force limiting means limits the driving force output from the electric motor when the temperature of the electric drive system is higher than the first threshold, the restriction release mitigating means includes the detected electric drive The restriction release relaxation control may be stopped when a time integral value of the temperature of the electric drive system after the system temperature becomes higher than the first threshold exceeds a predetermined value. . If it carries out like this, generation | occurrence | production of the malfunction of the electric motor by continuing a high temperature state can be suppressed.

  In the automobile of the present invention, the power output means may be a means including an internal combustion engine capable of outputting power to the first wheel. In the vehicle of the present invention of this aspect, the power output means is connected to three axes of the output shaft of the internal combustion engine, a drive shaft connected to the first axle, and a third rotating shaft, Three-axis power input / output means for inputting / outputting power to / from the remaining one axis based on power input / output to / from any two axes, and a rotating shaft capable of inputting / outputting power to / from the third rotating shaft It may be a means provided with an electric motor and a drive shaft electric motor capable of inputting / outputting power to / from the drive shaft, and the power output means is a first connected to the output shaft of the internal combustion engine. A rotor and a second rotor connected to a drive shaft connected to the first axle, and the first rotor and the second rotor are relatively moved by electromagnetic action. A counter-rotor electric motor that rotates the motor and a drive shaft motor that can input and output power to the previous drive shaft It can also be assumed to be a stage.

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

  FIG. 1 shows an outline of a configuration of a hybrid vehicle 20 according to an embodiment of the present invention. A hybrid vehicle 20 according to a configuration example includes an engine 22 and a crankshaft 26 as an output shaft of the engine 22 as illustrated. A three-shaft power distribution and integration mechanism 30 connected via the damper 28, a power-generating motor MG1 connected to the power distribution and integration mechanism 30, and the front wheels 63a and 63b connected to the power distribution and integration mechanism 30 A reduction gear 35 attached to a ring gear shaft 32a as a drive shaft connected to the front shaft 64 via a differential gear 62, a motor MG2 connected to the reduction gear 35, and rear shafts 67 of the rear wheels 66a and 66b The motor MG3 connected via the differential gear 65 and the hybrid electronic control that controls the entire drive system And a unit 70.

  The engine 22 is an internal combustion engine that outputs power using a hydrocarbon-based fuel such as gasoline or light oil, and an engine electronic control unit (hereinafter referred to as an engine ECU) that receives signals from various sensors that detect the operating state of the engine 22. ) 24 is subjected to operation control such as fuel injection control, ignition control, intake air amount adjustment control and the like. The engine ECU 24 is in communication with the hybrid electronic control unit 70, controls the operation of the engine 22 by a control signal from the hybrid electronic control unit 70, and, if necessary, transmits data related to the operating state of the engine 22 to the hybrid electronic control. Output to unit 70.

  The power distribution and integration mechanism 30 includes an external gear sun gear 31, an internal gear ring gear 32 arranged concentrically with the sun gear 31, a plurality of pinion gears 33 that mesh with the sun gear 31 and mesh with the ring gear 32, A planetary gear mechanism is provided that includes a carrier 34 that holds a plurality of pinion gears 33 so as to rotate and revolve, and that performs differential action using the sun gear 31, the ring gear 32, and the carrier 34 as rotational elements. In the power distribution and integration mechanism 30, the crankshaft 26 of the engine 22 is connected to the carrier 34, the motor MG1 is connected to the sun gear 31, and the reduction gear 35 is connected to the ring gear 32 via a ring gear shaft 32a as a drive shaft. When the motor MG1 functions as a generator, the power from the engine 22 input from the carrier 34 is distributed according to the gear ratio between the sun gear 31 side and the ring gear 32 side, and from the carrier 34 when the motor MG1 functions as an electric motor. The input power from the engine 22 and the power from the motor MG1 input from the sun gear 31 are integrated and output to the ring gear 32 side. The power output to the ring gear 32 is finally output from the ring gear shaft 32a to the front wheels 63a and 63b of the vehicle via the gear mechanism 60 and the differential gear 62.

  Motors MG1, MG2, and MG3 are all configured as well-known synchronous generator motors that can be driven as generators and as motors, and exchange power with battery 50 via inverters 41, 42, and 43. The electric power line 54 connecting the inverters 41, 42, 43 and the battery 50 is configured as a positive electrode bus and a negative electrode bus shared by the inverters 41, 42, 43, and generates power with any of the motors MG1, MG2, MG3. The electric power generated can be consumed by other motors. Therefore, the battery 50 is charged / discharged by electric power generated from any of the motors MG1, MG2, and MG3 or insufficient electric power. Note that the battery 50 is not charged / discharged if the power balance is balanced by the motors MG1, MG2, and MG3. The motors MG1, MG2, and MG3 are all driven and controlled by a motor electronic control unit (hereinafter referred to as a motor ECU) 40. The motor ECU 40 receives signals necessary for driving and controlling the motors MG1, MG2, and MG2, such as signals from rotational position detection sensors 44, 45, and 46 that detect the rotational positions of the rotors of the motors MG1, MG2, and MG3. A phase current applied to motors MG1, MG2, and MG3 detected by a current sensor (not shown), a signal from temperature sensor 48 that detects the temperature of motor MG3, a signal from temperature sensor 49 that detects the temperature of inverter 43, and the like. The motor ECU 40 outputs a switching control signal to the inverters 41, 42, and 43. The motor ECU 40 communicates with the hybrid electronic control unit 70, and controls the driving of the motors MG 1, MG 2, MG 3 by the control signal from the hybrid electronic control unit 70 and operates the motors MG 1, MG 2, MG 3 as necessary. Data on the state is output to the hybrid electronic control unit 70.

  The battery 50 is managed by a battery electronic control unit (hereinafter referred to as a battery ECU) 52. The battery ECU 52 receives signals necessary for managing the battery 50, for example, a voltage between terminals from a voltage sensor (not shown) installed between terminals of the battery 50, and a power line 54 connected to the output terminal of the battery 50. The charging / discharging current from the attached current sensor (not shown), the battery temperature from the temperature sensor (not shown) attached to the battery 50, and the like are input. Output to the control unit 70. The battery ECU 52 also calculates the remaining capacity (SOC) based on the integrated value of the charge / discharge current detected by the current sensor in order to manage the battery 50.

  A hydraulic brake 68 a that is operated by hydraulic pressure from the break actuator 68 is attached to the front wheels 63 a and 63 b and the rear wheels 66 a and 66 b. Adjustment of hydraulic pressure from the brake actuator 68 is performed by drive control by the brake ECU 69. A wheel speed signal from a wheel speed sensor 69a that detects the rotational speeds of the front wheels 63a and 63b and the rear wheels 66a and 66b is input to the brake ECU 69 via an input port (not shown). The brake ECU 69 communicates with the hybrid electronic control unit 70, and controls the drive of the brake actuator 68 by a control signal from the hybrid electronic control unit 70. The brake ECU 69 operates the hydraulic brake 68a and the front wheel 63a as necessary. , 63b and the state of the rear wheels 66a, 66b are output to the hybrid electronic control unit 70.

  The hybrid electronic control unit 70 is configured as a microprocessor centered on the CPU 72, and in addition to the CPU 72, a ROM 74 for storing processing programs, a RAM 76 for temporarily storing data, an input / output port and communication not shown. And a port. The hybrid electronic control unit 70 includes an ignition signal from an ignition switch 80, a shift position SP from a shift position sensor 82 that detects the operation position of the shift lever 81, and an accelerator pedal position sensor 84 that detects the amount of depression of the accelerator pedal 83. The accelerator opening Acc from the vehicle, the brake pedal position BP from the brake pedal position sensor 86 that detects the amount of depression of the brake pedal 85, the vehicle speed V from the vehicle speed sensor 88, the road surface gradient θ from the gradient sensor 89 that detects the road surface gradient, etc. Is input via the input port. As described above, the hybrid electronic control unit 70 is connected to the engine ECU 24, the motor ECU 40, the battery ECU 52, and the brake ECU 69 via the communication port, and the engine ECU 24, the motor ECU 40, the battery ECU 52, the brake ECU 69, and various control signals. And exchanging data.

  The hybrid vehicle 20 of the embodiment configured in this manner calculates a required torque to be output to the vehicle based on the accelerator opening Acc and the vehicle speed V corresponding to the depression amount of the accelerator pedal 83 by the driver, The engine 22 and the motors MG1, MG2, and MG3 are controlled for operation so that the corresponding required power is output. As the operation control of the engine 22 and the motors MG1, MG2, and MG3, the engine 22 is operated and controlled so that power corresponding to the required power is output from the engine 22, and all of the power output from the engine 22 is a power distribution integration mechanism. 30, a torque conversion operation mode in which the motor MG1, the motor MG2, and the motor MG3 are controlled to be torque-converted and output to the ring gear shaft 32a by any one or both of the motor 30, the motor MG1, the motor MG2, and the motor MG3. The engine 22 is controlled so that power corresponding to the sum of the power required for charging and discharging of the battery 50 is output from the engine 22 and all of the power output from the engine 22 with charging and discharging of the battery 50 or Some of them are the power distribution and integration mechanism 30, the motor MG1, and the motor MG2. Charge / discharge operation mode for controlling the motor MG1, the motor MG2, and the motor MG3 so that the required power is output to the ring gear shaft 32a with torque conversion by one or both of the motor MG3 and the operation of the engine 22 is stopped. Then, there is a motor operation mode in which operation control is performed so that power corresponding to the required power is output from one or both of the motor MG2 and motor MG3 to the ring gear shaft 32a.

  Next, the operation of the hybrid vehicle 20 of the embodiment thus configured, particularly the operation when performing 4WD traveling will be described. FIG. 2 is a flowchart showing an example of a drive control routine executed by the hybrid electronic control unit 70. This routine is repeatedly executed every predetermined time (for example, every 8 msec).

  When the drive control routine is executed, first, the CPU 72 of the hybrid electronic control unit 70 first determines the accelerator opening Acc from the accelerator pedal position sensor 84, the vehicle speed V, the wheel speeds Vf and Vr from the vehicle speed sensor 88, the engine 22 and the like. Data such as the rotational speeds Ne, Nm1, Nm2, and Nm3 of the motors MG1, MG2, and MG3, the remaining capacity SOC of the battery 50, the motor temperature Tm of the motor MG3, and the road surface gradient θ from the gradient sensor 89 are input (step S100). . Here, the rotation speed Ne is input as detected by a rotation speed sensor (not shown) that detects the rotation speed of the engine 22. As the rotation speeds Nm1, Nm2, and Nm3, those calculated based on the rotation positions from the rotation position detection sensors 44, 45, and 46 are input from the motor ECU 40 by communication. As the wheel speeds Vf and Vr, the wheel speed Vf of the front wheels 63a and 63b and the wheel speed Vr of the rear wheels 66a and 66b from the wheel speed sensor 69a are input from the brake ECU 69 by communication. The remaining capacity SOC is calculated from the charge / discharge current of the battery 50 from the current sensor and input from the battery ECU 52 by communication. The motor temperature Tm detected by the temperature sensor 48 is input from the motor ECU 40 by communication.

  Subsequently, a process of setting a required torque T * and a required power P * required for the vehicle based on the input accelerator opening Acc and the vehicle speed V is performed (step S110). In the embodiment, the required torque T * is obtained in advance by storing the relationship between the accelerator opening Acc, the vehicle speed V, and the required torque T * in the ROM 74 as a required torque setting map. When given, the required torque T * corresponding to the required torque setting map is derived and set. An example of the required torque setting map is shown in FIG. The required power P * is set to a value calculated by multiplying the set required torque T * by the vehicle speed V.

  Then, slip determination due to idling of the front wheels 63a and 63b and the rear wheels 66a and 66b is performed (step S120). This determination is made, for example, by comparing temporal changes (acceleration) of the wheel speeds Vf and Vr from the wheel speed sensor 69a with threshold values, or the rotational speed of the motor MG2 mechanically connected to the front wheels 63a and 63b. The time change (rotational acceleration) of Nm2 and the time change (rotational acceleration) of the rotational speed Nm3 of the motor MG3 mechanically connected to the rear wheels 66a and 66b can be respectively compared with a threshold value. When the slip is determined, the hybrid electronic control unit 70 determines whether or not the slip has occurred and whether the front wheel 63a or 63b or the rear wheel 66a or 66b slips when the slip occurs. The distinction is written at a predetermined address in the RAM 76.

  When the slip is determined, a process of setting a distribution ratio D for distributing the required torque T * to the front shaft 64 and the rear shaft 67 is performed (step S130). Here, the distribution ratio D is the ratio of the torque output to the front shaft 64 to the total torque output to the front shaft 64 and the rear shaft 67, and is set based on the running state of the vehicle. For example, 1.0 is set so that torque is output only to the front shaft 64 during normal traveling, or 0.8 so that torque is output to the rear shaft 67 in addition to the front shaft 64 during traveling on a slope or starting. Or a value such as 0.7 is set, or when the slip occurs, the ratio of the torque output to the wheel where the slip occurs is reduced and the ratio of the torque output to the wheel where the slip does not occur increases. You can do it. When the distribution ratio D is set, the required torque T * to be output to the front shaft 64 is set by multiplying the set distribution ratio D by the required torque T *, and the required torque T * is obtained by subtracting the distribution ratio D from the value 1. Is set to the required torque Tr * to be output to the rear shaft 67 (step S140).

  When the required torque Tf * to be output to the front shaft 64 is set, an output from the engine 22 is obtained by summing the required torque Tf * multiplied by the vehicle speed V, the charge / discharge request amount Pch * of the battery 50 and the loss (Loss). The engine required power Pe * to be set is set (step S150). Here, the required charge / discharge amount Pch * can be obtained from the remaining capacity SOC of the battery 50, the accelerator opening degree Acc, and the like.

  When the engine required power Pe * is set, a process for setting the target rotational speed Ne * and the target torque Te * of the engine 22 based on the set engine required power Pe * is performed (step S160). This process is performed by setting the target rotational speed Ne * and the target torque Te * based on the operation line for efficiently operating the engine 22 and the engine required power Pe *. FIG. 4 shows an example of the operation line of the engine 22 and how the target rotational speed Ne * and the target torque Te * are set. As shown in the figure, the target rotational speed Ne * and the target torque Te * can be obtained from the intersection of the operation line and a curve with a constant target power Pe * (Ne * × Te *).

  When the target rotational speed Ne * is set, a torque command Tm1 * to be output from the motor MG1 is set by the following equation (1) based on the set target rotational speed Ne * and the current rotational speed Ne of the engine 22 ( In step S170), a torque command Tm2 * to be output from the motor MG2 is set according to the following equation (2) based on the required torque Tf * of the front shaft 64, the torque command Tm1 *, and the gear ratio ρ of the power distribution and integration mechanism 30. (Step S180) Based on the required torque Tr * of the rear shaft 67, a temporary motor torque Tm3tmp to be output from the motor MG3 is set by the following equation (3) (Step S190). FIG. 5 is a collinear diagram showing the dynamic relationship between the rotating elements of the power distribution and integration mechanism 30. In the drawing, the right S-axis indicates the rotational speed of the sun gear 31, the C-axis indicates the rotational speed of the carrier 34, and the left R-axis indicates the rotational speed Nr of the ring gear 32 (ring gear shaft 32a). As shown in the figure, since the rotational speed of the engine 22 can be adjusted by the motor MG1, the engine 22 is controlled by driving the motor MG1 by setting the torque command Tm1 * according to the equation (1). Can be rotated. Further, the torque command Tm2 * of the motor MG2 can be set by solving the equation of torque balance in the drive shaft in FIG. Here, “KP” in Equation (1) indicates the gain of the proportional term, and “KI” indicates the gain of the integral term. “Gf” in Expression (2) is the ratio of the rotational speed of the ring gear shaft 32 a to the rotational speed of the front shaft 64, and “γ” is the speed reduction ratio of the reduction gear 35. “Gr” in Expression (3) is the ratio of the rotational speed Nm3 of the motor MG3 to the rotational speed of the rear shaft 67.

次に、モータＭＧ３のモータ温度Ｔｍと閾値Ｔ１ｒｅｆとを比較する（ステップＳ２００）。ここで、閾値Ｔ１ｒｅｆは、許容限界温度よりも低い温度のうちモータＭＧ３の発熱を抑制する必要がある温度として予め設定されている。モータ温度Ｔｍが閾値Ｔ１ｒｅｆ以下のときには、モータＭＧ３から出力するトルクの制限は不要と判断して、仮モータトルクＴｍ３ｔｍｐをそのままモータＭＧ３のトルク指令Ｔｍ３＊として設定し（ステップＳ２１０）、設定した各指令値のうち目標回転数Ｎｅ＊と目標トルクＴｅ＊についてはエンジンＥＣＵ２４に、トルク指令Ｔｍ１＊，Ｔｍ２＊，Ｔｍ３＊についてはモータＥＣＵ４０にそれぞれ送信して（ステップＳ２９０）、本ルーチンを終了する。目標回転数Ｎｅ＊と目標トルクＴｅ＊とを受信したエンジンＥＣＵ２４は、エンジン２２が目標回転数Ｎｅ＊と目標トルクＴｅ＊とに見合うポイントで運転されるよう燃料噴射制御や点火制御などの制御を行なう。また、トルク指令Ｔｍ１＊，Ｔｍ２＊を受信したモータＥＣＵ４０は、モータＭＧ１，ＭＧ２，ＭＧ３からそれぞれ目標トルクＴｍ１＊，Ｔｍ２＊，Ｔｍ３＊に見合うトルクが出力されるようインバータ４１，４２，４３のスイッチング素子をスイッチング制御する。

Next, the motor temperature Tm of the motor MG3 is compared with the threshold value T1ref (step S200). Here, the threshold value T1ref is set in advance as a temperature that needs to suppress the heat generation of the motor MG3 among the temperatures lower than the allowable limit temperature. When the motor temperature Tm is equal to or lower than the threshold T1ref, it is determined that it is unnecessary to limit the torque output from the motor MG3, and the temporary motor torque Tm3tmp is set as it is as the torque command Tm3 * of the motor MG3 (step S210). Among the values, the target rotational speed Ne * and the target torque Te * are transmitted to the engine ECU 24, and the torque commands Tm1 *, Tm2 *, Tm3 * are transmitted to the motor ECU 40 (step S290), and this routine is terminated. The engine ECU 24 that has received the target rotational speed Ne * and the target torque Te * performs control such as fuel injection control and ignition control so that the engine 22 is operated at a point corresponding to the target rotational speed Ne * and the target torque Te *. Do. The motor ECU 40 that has received the torque commands Tm1 *, Tm2 * switches the inverters 41, 42, 43 so that torques corresponding to the target torques Tm1 *, Tm2 *, Tm3 * are output from the motors MG1, MG2, MG3, respectively. Switching control of the element.

  On the other hand, when the motor temperature Tm of the motor MG3 is higher than the threshold value T1ref, it is determined that it is necessary to limit the torque output from the motor MG3. First, in step S120, it is determined that slip has occurred in the front wheels 63a, 63b. (Step S220), and when it is determined that the front wheels 63a and 63b are slipping, it is determined whether or not the road surface gradient θ input in step S100 is equal to or greater than a predetermined gradient θref as an ascending gradient (step S230). ). The processing of steps S220 and S230 is originally processing for determining whether or not the torque output from the motor MG3 should be limited, but whether the current running state of the vehicle has an urgency to escape from that state. is there. If it is determined in step S220 that no slip has occurred on the front wheels 63a, 63b, or if it is determined in step S230 that the road surface gradient θ is less than the predetermined gradient θ, the current running state of the vehicle should exit that state. The torque limit Tmax is set as an upper limit of the torque that may be output from the motor MG3 based on the motor temperature Tm (step S270), and the temporary motor torque Tm3tmp and the torque limit Tmax are set. The smaller one is set as the torque command Tm3 * of the motor MG3 (step S280).

  If slip occurs in the front wheels 63a and 63b and the road surface gradient θ is determined to be equal to or greater than the predetermined gradient θref, it is determined that the current vehicle traveling state has urgency to escape from the state, and a motor described later It is determined whether or not a restriction relaxation condition is satisfied as a condition for relaxing the torque limit of MG3 (step S240) and whether or not a state where the motor temperature Tm is higher than the threshold value T1ref continues for a predetermined time. (Step S250). Here, the restriction relaxation condition is, for example, a condition that the cumulative execution count counted by 1 each time the execution of the process of relaxing the torque limitation of the motor MG3 is less than a predetermined number, or the previous motor MG3 The time interval from the relaxation of the torque limit to the relaxation of the torque limit of the current motor MG3 is set to be a predetermined time or more, or the torque limit of the current motor MG3 is relaxed after the torque limit of the previous motor MG3 is relaxed. For example, the travel distance of the vehicle until the restriction is relaxed may be a condition that is a predetermined distance or more. As described above, the determination of the restriction relaxation condition and the determination of whether or not the state where the motor temperature Tm is higher than the threshold value T1ref continues for a predetermined time is caused by a problem that the motor MG3 is frequently driven at a high temperature. This is to prevent the occurrence of the above. If it is determined that the restriction relaxation condition is not satisfied, or if it is determined that the state where the motor temperature Tm is higher than the threshold value T1ref continues for a predetermined time, it is more likely that the current vehicle is more heated than the escape from the running state. It is determined that the protection of the motor MG3 should be prioritized, and based on the motor temperature Tm, a torque limit Tmax is set as an upper limit of torque that may be output from the motor MG3 (step S270), and the temporary motor torque Tm3tmp and the torque are set. The smaller one of the limits Tmax is set as the torque command Tm3 * for the motor MG3 (step S280). On the other hand, when it is determined that the restriction relaxation condition is satisfied and the state where the motor temperature Tm is higher than the threshold value T1ref has not continued for a predetermined time, priority should be given to escape from the current running state of the vehicle. First, the motor temperature Tm is compared with a threshold value T2ref larger than the threshold value T1ref (step S260). When the motor temperature Tm is equal to or lower than the threshold value T2ref, the temporary motor torque Tm3tmp set in step S190 is directly used as a torque command. When Tm3 * is set (step S210) and the motor temperature Tm is higher than the threshold value T2ref, the torque limit Tmax is set as the upper limit of the torque that may be output from the motor MG3 based on the motor temperature Tm (step S270). , Provisional motor torque Tm3tmp and torque limit Tmax Among sets the smaller as the torque command of the motor MG3 Tm3 * (step S280). Here, the threshold value T2ref is set as a temperature that requires cooling of the motor MG3 among temperatures lower than the allowable limit temperature. As described above, since the temporary motor torque Tm3tmp is set as the torque command Tm3 * until the motor temperature Tm becomes higher than the threshold value T1ref and becomes equal to or lower than the threshold value T2ref, the speed from the slope with a low μ (friction coefficient) can be increased. Escape is possible.

  FIG. 6 is an explanatory diagram for explaining the temporal change of the motor temperature Tm and the torque command Tm3 * of the motor MG3. As shown in the figure, normally, the torque output from the motor MG3 is limited in order to suppress heat generation at the time t1 when the motor temperature Tm of the motor MG3 becomes higher than the threshold value T1ref (see the solid line in FIG. 6). When the road surface gradient θ is equal to or greater than the predetermined gradient θref and the vehicle is in a traveling state in which slip occurs in the front wheels 63a and 63b, it is determined that the vehicle needs to be urgently escaped from this traveling state, and the motor temperature Tm is higher than the threshold value T1ref. Even then, the torque output from the motor MG3 is not limited until it becomes higher than the threshold value T2ref (time t2) (see the dotted line in FIG. 6).

  According to the hybrid vehicle 20 of the embodiment described above, when the road surface gradient θ is greater than or equal to the predetermined gradient θref and slip occurs in the front wheels 63a and 63b, the output torque to the front wheels 63a and 63b is reduced and rearized due to the occurrence of this slip. Even when the temperature of the motor MG3 (motor temperature Tm) connected to the rear wheels 66a and 66b becomes higher than the threshold value T1ref with respect to the increase in the output torque to the wheels 66a and 66b, the torque of the motor MG3 is not limited. When the temperature of the motor MG3 becomes higher than the threshold value T2ref, the torque limitation of the motor MG3 is started. Therefore, it is possible to escape from the low μ slope while suppressing excessive heat generation of the motor MG3. In addition, even when the temperature of the motor MG3 is equal to or lower than the threshold value T2ref, when the restriction relaxation condition is not satisfied or when the state higher than the threshold value T1ref continues for a predetermined time, the torque of the motor MG3 is immediately limited. The motor MG3 can be more reliably protected from heat.

  In the hybrid vehicle 20 of the embodiment, when the road surface gradient θ is equal to or greater than the predetermined gradient θref and slip occurs in the front wheels 63a and 63b, the torque limitation of the motor MG3 connected to the rear wheels 66a and 66b is relaxed. However, the torque limit of the motor MG3 may be relaxed when the road surface gradient θ is equal to or greater than the predetermined gradient θref, and the torque of the motor MG3 may be limited when the front wheels 63a and 63b are slipping. It may be relaxed. Further, the present invention is not limited thereto, and the torque limit of the motor MG3 may be canceled or relaxed for any traveling state of the vehicle that needs to escape.

  In the hybrid vehicle 20 of the embodiment, the torque from the motor MG3 is limited based on the temperature of the motor MG3 (motor temperature Tm), but the torque from the motor MG3 is limited based on the temperature of the inverter 43. Alternatively, the torque from the motor MG3 may be limited based on the temperature of the motor MG3 and the temperature of the inverter 43.

  In the hybrid vehicle 20 of the embodiment, when the motor temperature Tm is higher than the threshold value T1ref for a predetermined time in step S250, the torque from the motor MG3 is limited even if the motor temperature Tm is equal to or lower than the threshold value T2ref. However, instead of step S250, the calculation of the time integral value of the motor temperature Tm is started when it becomes higher than the threshold value T1ref, and when the calculated time integral value becomes larger than the predetermined value, the motor temperature Tm is The torque from the motor MG3 may be limited even if it is equal to or less than the threshold value T2ref.

  In the hybrid vehicle 20 of the embodiment, the road surface gradient θ detected directly by the gradient sensor 89 is used, but the torque T output to the front shaft 64 and the rear shaft 67 during the traveling or stopping process and the vehicle What is calculated from the relationship with the acceleration α (Tθ = T−M · α; “Tθ” is a balance torque related to the road surface gradient θ, “M” is the vehicle weight) may be used. What is estimated based on the detection value of the G sensor (not shown) when it is determined that the front wheels 63a and 63b have slipped is less than the predetermined vehicle speed may be used.

  In the hybrid vehicle 20 of the embodiment, the engine 22, the power distribution and integration mechanism 30, and the motors MG1 and MG2 are connected to the front shaft 64, and the motor MG3 is connected to the rear shaft 67. The motors MG1 and MG2 may be connected to the rear shaft 67, and the motor MG3 may be connected to the front shaft 64.

  In this embodiment, the present invention is applied to a hybrid vehicle capable of outputting power from the engine 22 to a ring gear shaft 32a as a drive shaft connected to the front wheels 63a and 63b via the power distribution and integration mechanism 30 by input / output of power from the motor MG1. As described above, the present invention is applicable to any type of vehicle as long as the vehicle includes a power output device capable of outputting power to one of the front wheels and the rear wheel and an electric motor capable of outputting power to the other wheel. be able to. For example, as illustrated in FIG. 7, instead of the power distribution and integration mechanism 30 and the motor MG1, an inner rotor 132 connected to the crankshaft 26 of the engine 22 and an outer rotor 234 connected to the front wheels 63a and 63b are provided. However, the present invention may be applied to the hybrid vehicle 120 including the counter-rotor motor 130 that outputs a part of the power of the engine 22 to the front wheels 63a and 63b with input and output of electric power and power by electromagnetic action.

  The embodiments of the present invention have been described using the embodiments. However, the present invention is not limited to these embodiments, and can be implemented in various forms without departing from the gist of the present invention. Of course you get.

1 is a configuration diagram showing an outline of a configuration of a hybrid vehicle 20 according to an embodiment of the present invention. 4 is a flowchart showing an example of a drive control routine executed by a hybrid electronic control unit 70. It is explanatory drawing which shows an example of the map for request | requirement torque setting. It is explanatory drawing explaining a mode that the target rotation speed Ne * and the target torque Te * are set from engine request | requirement power Pe *. 4 is a collinear diagram showing a dynamic relationship between the rotational speed and torque of each rotary element of the power distribution and integration mechanism 30. FIG. It is explanatory drawing explaining the mode of the time change of motor temperature Tm of motor MG3, and torque instruction Tm3 *. 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 Hybrid vehicle, 22 engine, 24 electronic control unit (engine ECU) for engine, 26 crankshaft, 28 damper, 30 power distribution integration mechanism, 31 sun gear, 32 ring gear, 32a ring gear shaft, 33 pinion gear, 34 carrier, 35 Reduction gear, 40 Motor electronic control unit (motor ECU), 41, 42, 43 Inverter, 44, 45, 46 Rotation position detection sensor, 48 Temperature sensor, 49 Temperature sensor, 50 Battery, 52 Battery electronic control unit (Battery ECU), 54 power line, 60 gear mechanism, 62, 65 differential gear, 63a, 63b front wheel, 64 front axle, 66a, 66b rear wheel, 67 rear axle, 68 brake actuator, 68a hydraulic brake, 69 Brake ECU, 69a Wheel speed sensor, 70 Hybrid electronic control unit, 72 CPU, 74 ROM, 76 RAM, 80 Ignition switch, 81 Shift lever, 82 Shift position sensor, 83 Accel pedal, 84 Accel pedal position sensor, 85 Brake pedal , 86 Brake pedal position sensor, 88 Vehicle speed sensor, 89 Gradient sensor, 130 Pair rotor motor, 132 Inner rotor 134 Outer rotor, MG1, MG2, MG3 motor.

Claims (11)

An automobile capable of outputting power to the first wheel and the second wheel,
Power output means capable of outputting power to the first wheel;
An electric motor capable of outputting power to the second wheel;
Drive control means for driving and controlling the power output means and the electric motor so that a required drive force as a required value of the drive force for running the vehicle is output;
Temperature detecting means for detecting the temperature of an electric drive system including the electric motor;
Driving force limiting means for limiting the driving force output from the electric motor based on the detected temperature of the electric drive system;
An automobile comprising: a restriction release relaxation means for executing restriction release relaxation control for releasing or relaxing the restriction of the driving force output from the electric motor by the driving force restriction means when the vehicle reaches a predetermined traveling state. The automobile according to claim 1,
The driving force limiting means is a means for limiting the driving force output from the electric motor when the detected temperature of the electric drive system is higher than a first threshold;
The restriction release relaxation means is a means for executing the restriction release relaxation control when the detected temperature of the electric drive system is equal to or lower than a second threshold value that is greater than the first threshold value.   The automobile according to claim 1 or 2, wherein the restriction release mitigating means is means for executing the restriction mitigation control when the road surface gradient is equal to or greater than a predetermined gradient as the climbing gradient in the predetermined traveling state. The automobile according to any one of claims 1 to 3,
When a slip occurs on the first wheel, the drive control means controls the drive of the power output means so that the generated slip is suppressed and also controls the electric motor so as to correspond to the required driving force. Means,
The restriction release relaxation means is a vehicle that executes the restriction release relaxation control when a slip is generated in the first wheel as the predetermined traveling state. The automobile according to any one of claims 1 to 4,
A cumulative execution number storage means for storing the cumulative execution number of the restriction release relaxation control;
The restriction release relaxation means is a means for not executing the restriction release relaxation control when the stored cumulative number of executions exceeds a predetermined number.   The restriction release relaxation means is means for not executing the restriction release relaxation control until a predetermined time elapses after the restriction release relaxation control is executed last time and / or until the vehicle travels a predetermined distance. The automobile according to any one of 5 to 5.   3. The restriction release relaxation means is means for stopping the restriction release relaxation control when a state in which the detected temperature of the electric drive system is higher than the first threshold continues for a second predetermined time. The automobile according to any one of claims 3 to 6.   The restriction release relaxation means reduces the restriction release when the time integral value of the temperature of the electric drive system after the detected temperature of the electric drive system becomes higher than the first threshold exceeds a predetermined value. The automobile according to any one of claims 3 to 7, which is means for stopping control.   The automobile according to any one of claims 1 to 8, wherein the power output means is a means including an internal combustion engine capable of outputting power to the first wheel.   The power output means is connected to three axes of an output shaft of the internal combustion engine, a drive shaft connected to the first axle, and a third rotary shaft, and is input / output to any two of the three shafts. A three-axis power input / output means for inputting / outputting power to / from the remaining one shaft based on the power; a rotary shaft electric motor capable of inputting / outputting power to / from the third rotating shaft; The vehicle according to claim 9, wherein the vehicle includes a drive shaft electric motor capable of inputting and outputting.   The power output means has a first rotor connected to the output shaft of the internal combustion engine and a second rotor connected to a drive shaft connected to the first axle, and electromagnetically A counter-rotor motor that relatively rotates the first rotor and the second rotor by action, and a drive shaft motor that can input and output power to the previous drive shaft. 9. The automobile according to 9.

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