JP2006094626A - Hybrid vehicle and its control method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hybrid vehicle that can drive an engine so as to output power in a range where the engine is efficiently driven, and can charge a battery with surplus power as electricity, and its control method. <P>SOLUTION: When a condition that a vehicle speed V is not higher than a threshold Vre and a condition that a road gradient θ is not smaller than a threshold θref are satisfied in case that a motor is brought into a high-temperature state during motor traveling, the engine 22 is started when the engine is stopped (S116), a battery charging request Pb* is reset so that power not smaller than the lowest limit of the range where the engine is efficiently driven is outputted from the engine, requested power Pe* is reset by using the charging request Pb* (S118, S120), and the engine and the motor are controlled by using the requested power Pe* (S122 to S128). <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a hybrid vehicle and a control method thereof.

Conventionally, as this type of hybrid vehicle, an engine capable of outputting power to the rear wheels, a rear wheel motor capable of outputting power to the rear wheels and generating electricity using a part of the power from the engine, A four-wheel drive hybrid vehicle including a front wheel motor capable of outputting power to the front wheels has been proposed. (For example, refer to Patent Document 1). In this hybrid vehicle, when the front wheel motor becomes hot while running only with the power from the front wheel motor, the rear wheel motor is driven and the engine is started, and the power from the engine is used. I try to run.
JP 2003-129880 A

  However, in the above-described hybrid vehicle, when the front wheel motor becomes hot and the vehicle travels using the power from the started engine, the energy efficiency of the vehicle may deteriorate. Since the motor travel that travels with only the power from the rear wheel motor is performed at low speed, the power required by the vehicle is relatively small. Many engines improve efficiency when outputting a certain amount of power. Therefore, when traveling with relatively small power output from the engine, the engine must be operated at an inefficient driving point, which deteriorates the energy efficiency of the vehicle.

  The hybrid vehicle of the present invention aims to improve the energy efficiency of the vehicle.

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

The hybrid vehicle of the present invention
An internal combustion engine capable of outputting driving power;
An electric motor capable of outputting driving power;
A drive circuit used to drive the electric motor;
Power generation means capable of generating power using at least part of the power from the internal combustion engine;
Power storage means capable of exchanging electric power with the electric motor and the power generation means;
High temperature state detection means for detecting a predetermined high temperature state in the electric motor or the drive circuit;
Required power setting means for setting required power required for the vehicle;
During the predetermined electric running in which the predetermined high temperature state is detected by the high temperature state detection means while running only with the power from the electric motor with the operation of the internal combustion engine stopped based on a predetermined condition, The internal combustion engine is started so that the vehicle travels using the mechanical outputs of the internal combustion engine and the electric motor in parallel by the power based on the set required power by starting the internal combustion engine and the power storage means is charged. Control means for executing high temperature control for controlling the power generation means and the electric motor;
It is a summary to provide.

  In the hybrid vehicle of the present invention, when a predetermined high temperature state is detected in the electric motor or the drive circuit when running only with the electric motor while the operation of the internal combustion engine is stopped based on the predetermined condition, The internal combustion engine, the power generation means, and the motor are connected so that the vehicle travels and the power storage means is charged by using the mechanical outputs of the internal combustion engine and the electric motor in parallel by the power based on the required power set by starting the internal combustion engine. Control. That is, at the time of predetermined electric running, the internal combustion engine is started and the vehicle is run using both the mechanical outputs of the internal combustion engine and the electric motor together so that the power storage means is charged. Thereby, since the load of an electric motor can be reduced, it can cope with the high temperature state of an electric motor or its drive circuit. Further, since the power storage means is controlled to be charged, the internal combustion engine is operated so that power larger than the required power is output from the internal combustion engine. Thereby, the fall of the efficiency of the internal combustion engine based on outputting small motive power can be suppressed, and the energy efficiency of a vehicle can be improved.

  In such a hybrid vehicle of the present invention, the predetermined condition may be a condition in which the set required power is less than a predetermined power set as a lower limit value for efficiently operating the internal combustion engine. it can. In this case, the control means may be means for controlling the internal combustion engine so that power that exceeds the predetermined power is output from the started internal combustion engine during the predetermined electric running. In this way, since the motive power equal to or higher than the lower limit value for efficiently operating the internal combustion engine is output from the internal combustion engine, the internal combustion engine can be efficiently operated and the energy efficiency of the vehicle can be further improved.

  The hybrid vehicle of the present invention further includes temperature detection means for detecting a temperature of the electric motor or the drive circuit, and the control means is based on the detected temperature of the electric motor or the drive circuit during the predetermined electric driving. The starting power smaller than the predetermined power may be set, and the high temperature control may be performed when the set required power is equal to or higher than the set starting power. In this case, the control means may be means for setting the starting power such that the higher the temperature of the electric motor is, the smaller the electric power is. If it carries out like this, an internal combustion engine can be started more appropriately with respect to the temperature of an electric motor or a drive circuit.

  The hybrid vehicle of the present invention further includes required power setting means for setting required power to be input / output to / from the power storage means based on the state of the power storage means, and the required power setting means is for driving required for traveling. The means for setting the required power based on the sum of the power and the required power set by the required power setting means, and the control means sets the required power by the required power setting means during the predetermined electric travel. Instead, it may be a means for executing the high temperature control by setting the required power so that the set required power is equal to or greater than the predetermined power. In this way, it is possible to execute the high temperature control only by setting the required power.

  The hybrid vehicle of the present invention includes vehicle speed detecting means for detecting a vehicle speed, and the control means is means for executing the high temperature control when the detected vehicle speed is equal to or lower than a predetermined vehicle speed during the predetermined electric driving. Or a road surface gradient detecting unit that detects a road surface gradient, and the control unit executes the high temperature control when the detected road surface gradient is greater than or equal to a predetermined gradient during the predetermined electric running. It can also be assumed.

  In such a hybrid vehicle of the present invention, the high temperature state detecting means detects the temperature of the electric motor, and when the detected temperature of the electric motor is equal to or higher than a first predetermined temperature or the detected temperature of the electric motor and the electric motor It may be a means for detecting the predetermined high temperature state when the temperature of the electric motor is estimated to be equal to or higher than a second predetermined temperature within a predetermined time based on a change in temperature with time, The high temperature state detection means detects the temperature of the drive circuit and when the detected temperature of the drive circuit is equal to or higher than a first predetermined temperature, or the detected temperature of the drive circuit and the time change of the temperature of the drive circuit On the basis of the above, the predetermined high temperature state may be detected when it is estimated that the temperature of the drive circuit becomes equal to or higher than the second predetermined temperature within a predetermined time.

  In the hybrid vehicle of the present invention, the power generation means is connected to an output shaft of the internal combustion engine and a drive shaft connected to the axle, and includes at least a part of the power of the internal combustion engine with input and output of power and power. Can also be a means capable of outputting to the drive shaft. In this case, the power generation means is connected to the three shafts of the output shaft of the internal combustion engine, the drive shaft, and the rotation shaft, and the remaining shaft based on the power input / output to / from any two of the three shafts. It is also possible to use a three-shaft power input / output means for inputting / outputting power to the rotary shaft and a generator capable of inputting / outputting power to / from the rotary shaft. A first rotor connected to the output shaft and a second rotor connected to the drive shaft; and rotation by relative rotation of the first rotor and the second rotor It can also be assumed that it is a counter-rotor generator.

The hybrid vehicle control method of the present invention includes:
An internal combustion engine capable of outputting power for traveling, an electric motor capable of outputting power for traveling, a drive circuit used for driving the motor, and at least part of the power from the internal combustion engine can generate electric power A control method for a hybrid vehicle comprising: a power generation means; and an electric storage means capable of exchanging electric power with the electric motor and the power generation means,
Determining whether the motor or the drive circuit is in a predetermined high temperature state;
Set the required power required for the vehicle,
During the predetermined electric running in which the predetermined high temperature state is detected by the high temperature state detection means while running only with the power from the electric motor with the operation of the internal combustion engine stopped based on a predetermined condition, The internal combustion engine is started so that the vehicle travels using the mechanical outputs of the internal combustion engine and the electric motor in parallel by the power based on the set required power by starting the internal combustion engine and the power storage means is charged. The gist is to control the power generation means and the electric motor.

  In this hybrid vehicle control method of the present invention, when a predetermined high-temperature state is detected in the electric motor or the drive circuit when the internal combustion engine is running with only the electric motor stopped based on the predetermined condition. The internal combustion engine and the power generation means are configured so that the vehicle travels and the power storage means is charged by using the mechanical outputs of the internal combustion engine and the electric motor in parallel by power based on the required power set by starting the internal combustion engine. Control the motor. That is, at the time of predetermined electric running, the internal combustion engine is started and the vehicle is run using both the mechanical outputs of the internal combustion engine and the electric motor together so that the power storage means is charged. Thereby, since the load of an electric motor can be reduced, it can cope with the high temperature state of an electric motor or its drive circuit. Further, since the power storage means is controlled to be charged, the internal combustion engine is operated so that power larger than the required power is output from the internal combustion engine. Thereby, the fall of the efficiency of the internal combustion engine based on outputting small motive power can be suppressed, and the energy efficiency of a vehicle can be improved.

  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 the configuration of a hybrid vehicle 20 according to an embodiment of the present invention. As shown in the figure, the hybrid vehicle 20 of the embodiment includes an engine 22, a three-shaft power distribution / integration mechanism 30 connected to a crankshaft 26 as an output shaft of the engine 22 via a damper 28, and power distribution / integration. A motor MG1 capable of generating electricity connected to the mechanism 30, a reduction gear 35 attached to a ring gear shaft 32a as a drive shaft connected to the power distribution and integration mechanism 30, a motor MG2 connected to the reduction gear 35, And a hybrid electronic control unit 70 for controlling the entire vehicle.

  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 the ring gear shaft 32a. When functioning as a generator, 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 when the motor MG1 functions as an electric motor, the engine input from the carrier 34 The power from 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 drive wheels 63a and 63b of the vehicle via the gear mechanism 60 and the differential gear 62.

  The motor MG1 and the motor MG2 are both configured as well-known synchronous generator motors that can be driven as generators and can be driven as motors, and exchange power with the battery 50 via inverters 41 and 42. The power line 54 connecting the inverters 41 and 42 and the battery 50 is configured as a positive electrode bus and a negative electrode bus shared by the inverters 41 and 42, and the electric power generated by one of the motors MG1 and MG2 It can be consumed by a motor. Therefore, battery 50 is charged / discharged by electric power generated from one of motors MG1 and MG2 or insufficient electric power. If the balance of electric power is balanced by the motors MG1 and MG2, the battery 50 is not charged / discharged. The motors MG1 and MG2 are both driven and controlled by a motor electronic control unit (hereinafter referred to as a motor ECU) 40. The motor ECU 40 includes signals necessary for driving and controlling the motors MG1 and MG2, such as signals from rotational position detection sensors 43 and 44 for detecting the rotational positions of the rotors of the motors MG1 and MG2, and motors from the temperature sensor 45. The temperature of MG2, the phase current applied to the motors MG1 and MG2 detected by a current sensor (not shown), and the like are input. The motor ECU 40 outputs a switching control signal to the inverters 41 and 42. The motor ECU 40 is in communication with the hybrid electronic control unit 70, controls the driving of the motors MG1 and MG2 by a control signal from the hybrid electronic control unit 70, and, if necessary, data on the operating state of the motors MG1 and MG2. 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 the terminals of the battery 50, and a power line 54 connected to the output terminal of the battery 50. A charging / discharging current or the like from an attached current sensor (not shown) is input, and data regarding the state of the battery 50 is output to the hybrid electronic control unit 70 by communication as necessary. 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.

  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 pedal opening Acc from the vehicle, the brake pedal position BP from the brake pedal position sensor 86 for detecting the depression amount of the brake pedal 85, the vehicle speed V from the vehicle speed sensor 88, the road surface gradient θ from the gradient sensor 90, etc. Have been entered. As described above, the hybrid electronic control unit 70 is connected to the engine ECU 24, the motor ECU 40, and the battery ECU 52 via the communication port, and exchanges various control signals and data with the engine ECU 24, the motor ECU 40, and the battery ECU 52. ing.

  The hybrid vehicle 20 of the embodiment thus configured calculates the required torque to be output to the ring gear shaft 32a as the drive shaft based on the accelerator opening Acc and the vehicle speed V corresponding to the depression amount of the accelerator pedal 83 by the driver. Then, the operation of the engine 22, the motor MG1, and the motor MG2 is controlled so that the required power corresponding to the required torque is output to the ring gear shaft 32a. As operation control of the engine 22, the motor MG1, and the motor MG2, the operation of the engine 22 is 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 the power distribution and integration mechanism 30. Torque conversion operation mode for driving and controlling the motor MG1 and the motor MG2 so that the torque is converted by the motor MG1 and the motor MG2 and output to the ring gear shaft 32a, and the required power and the power required for charging and discharging the battery 50. The engine 22 is operated and controlled so that suitable power is output from the engine 22, and all or part of the power output from the engine 22 with charging / discharging of the battery 50 is the power distribution and integration mechanism 30, the motor MG1, and the motor. The required power is converted to the ring gear shaft 32 with torque conversion by MG2. Charge / discharge operation mode in which the motor MG1 and the motor MG2 are driven and controlled to be output to each other, and a motor operation mode in which the operation of the engine 22 is stopped and the power corresponding to the required power from the motor MG2 is output to the ring gear shaft 32a. and so on.

  Next, the operation of the thus configured hybrid vehicle 20 of the embodiment 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 several 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 rotational speeds Nm1, Nm2 of the motors MG1, MG2, the temperature t of the motor MG2, Processing for inputting data necessary for control, such as the vehicle speed V from the vehicle speed sensor 88, the road surface gradient θ from the gradient sensor 90, the charge request Pb * of the battery 50, and the rotational speed Ne of the engine 22 is executed (step S100). Here, the rotation speed Ne of the engine 22 is calculated based on a signal from a crank position sensor (not shown) attached to the crankshaft 26 and is input from the engine ECU 24 by communication. The rotational speeds Nm1 and Nm2 of the motors MG1 and MG2 are calculated based on the rotational positions of the rotors of the motors MG1 and MG2 detected by the rotational position detection sensors 43 and 44, and the temperature t of the motor MG2 is the temperature. Those detected by the sensor 45 are input from the motor ECU 40 by communication. Further, the charge request Pb * for the battery 50 is input from the battery ECU 52 through communication, which is calculated based on the remaining capacity SOC of the battery 50 described above.

  When the data is thus input, the required torque Tr * to be output to the ring gear shaft 32a as the drive shaft connected to the drive wheels 63a and 63b as the torque required for the vehicle based on the input accelerator opening Acc and the vehicle speed V. And the required power Pe * required for the engine 22 is set (step S102). In the embodiment, the required torque Tr * is determined in advance by storing the relationship between the accelerator opening Acc, the vehicle speed V, and the required torque Tr * in the ROM 74 as a required torque setting map, and the accelerator opening Acc, the vehicle speed V, , The corresponding required torque Tr * is derived and set from the stored map. FIG. 3 shows an example of the required torque setting map. The required power Pe * can be calculated as the sum of a value obtained by multiplying the set required torque Tr * by the rotation speed Nr of the ring gear shaft 32a and the charge / discharge required power Pb * required by the battery 50 and the loss Loss (formula (1)). The rotation speed Nr of the ring gear shaft 32a can be obtained by multiplying the vehicle speed V by the conversion factor k, or can be obtained by dividing the rotation speed Nm2 of the motor MG2 by the gear ratio Gr of the reduction gear 35.

  Pe * = Tr * × Nr + Pb * + Loss (1)

  Next, it is determined whether or not the calculated required power Pe * is greater than or equal to the threshold value Pref (step S104). Here, the threshold value Pref is used to determine whether the engine 22 is operated to run in the torque conversion operation mode or the charge / discharge operation mode, or whether the engine 22 is stopped and the motor operation mode is run. It is set as the lower limit of the range of power that can be output from the engine 22 relatively efficiently. When it is determined that the required power Pe * is equal to or greater than the threshold value Pref, the target rotational speed Ne * and the target torque Te * of the engine 22 are set based on the operation line for efficiently operating the engine 22 and the required power Pe *. (Step S122). 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 required power Pe * (Ne * × Te *).

  Subsequently, using the set target rotational speed Ne *, the rotational speed Nr (Nm2 / Gr) of the ring gear shaft 32a, and the gear ratio ρ of the power distribution and integration mechanism 30, the target rotational speed Nm1 of the motor MG1 is given by the following equation (2). * Is calculated and a torque command Tm1 * of the motor MG1 is calculated by Equation (3) based on the calculated target rotational speed Nm1 * and the current rotational speed Nm1 (step S124). Here, Expression (2) is a dynamic relational expression for the rotating element of the power distribution and integration mechanism 30. FIG. 5 is a collinear diagram showing a dynamic relationship between the number of rotations and torque in the rotating elements of the power distribution and integration mechanism 30. In the figure, the left S-axis indicates the rotation speed of the sun gear 31 that is the rotation speed Nm1 of the motor MG1, the C-axis indicates the rotation speed of the carrier 34 that is the rotation speed Ne of the engine 22, and the R-axis indicates the rotation speed of the motor MG2. The rotational speed Nr of the ring gear 32 obtained by multiplying the number Nm2 by the gear ratio Gr of the reduction gear 35 is shown. Equation (2) can be easily derived by using this alignment chart. The two thick arrows on the R axis indicate that torque Te * output from the engine 22 when the engine 22 is normally operated at the operation point of the target rotational speed Ne * and the target torque Te * is transmitted to the ring gear shaft 32a. Torque and torque that the torque Tm2 * output from the motor MG2 acts on the ring gear shaft 32a via the reduction gear 35. Expression (3) is a relational expression in feedback control for rotating the motor MG1 at the target rotational speed Nm1 *. In Expression (3), “k1” in the second term on the right side is a gain of the proportional term. “K2” in the third term on the right side is the gain of the integral term.

Nm1 * ＝ Ne * ・ (1 + ρ) / ρ−Nm2 / (Gr ・ ρ) (2)
Tm1 * = previous Tm1 * + k1 (Nm1 * −Nm1) + k2∫ (Nm1 * −Nm1) dt (3)

  When the target rotation speed Nm1 * and the torque command Tm1 * of the motor MG1 are calculated in this way, the torque MG2 to be output from the motor MG2 using the required torque Tr *, the torque command Tm1 * and the gear ratio ρ of the power distribution and integration mechanism 30 is calculated. Torque command Tm2 * is calculated by equation (4) and set as torque command Tm2 * of motor MG2 (step S126), and target engine speed Ne * and target torque Te * of engine 22 are sent to engine ECU 24 for motor MG1, The torque commands Tm1 * and Tm2 * for MG2 are transmitted to the motor ECU 40 (step S128), and the drive control routine is terminated. Equation (4) can be easily derived by using the alignment chart of FIG. The engine ECU 24 that has received the target rotational speed Ne * and the target torque Te * performs fuel injection control in the engine 22 such that the engine 22 is operated at an operating point indicated by the target rotational speed Ne * and the target torque Te *. Controls such as ignition control. The motor ECU 40 that has received the torque commands Tm1 * and Tm2 * controls the switching elements of the inverters 41 and 42 so that the motor MG1 is driven by the torque command Tm1 * and the motor MG2 is driven by the torque command Tm2 *. To do.

  Tm2 * ＝ (Tr * ＋ Tm1 * / ρ) / Gr (4)

  On the other hand, when it is determined in step S104 that the required power Pe * is less than the threshold value Pref, it is determined whether the temperature t of the motor MG2 is equal to or higher than the threshold value tref, that is, whether it is in a high temperature state (step S106). Here, the threshold value tref is determined as a value equal to or lower than the upper limit of the temperature range in which the motor MG2 can be driven stably and continuously. When it is determined that the engine is not in a high temperature state, an instruction to stop the engine 22 is output to the engine ECU 24 and the engine 22 is stopped when the engine 22 is being operated so that the vehicle runs only with the power from the motor MG2. S108), the target engine speed Ne *, the target torque Te *, and the torque command Tm1 * of the engine 22 are set to zero (step S110), and the required torque Tr * is set to the torque command Tm2 * of the motor MG2 and the reduction gear 35 is set. A value divided by the gear ratio Gr is set (step S112), the target engine speed Ne * and the target torque Te * of the engine 22 are set to the engine ECU 24, and the torque commands Tm1 * and Tm2 * of the motors MG1 and MG2 are set to the motor ECU 40. (Step S128), and this routine is terminated. The engine ECU 24 that has received an instruction to stop the engine 22 stops the engine 22 by stopping control such as fuel injection control and ignition control. Further, the engine ECU 24 that has received the target rotational speed Ne * and the target torque Te * having a value of zero maintains a state in which control such as fuel injection control and ignition control is stopped.

  Thus, in the hybrid vehicle 20 of the embodiment, when the required power Pe * is equal to or greater than the threshold value Pref, the engine travels in the torque conversion operation mode or the charge / discharge operation mode, and the required power Pe * is less than the threshold value Pref. In some cases, the motor travel is usually performed in the motor operation mode.

  Consider a case where the motor MG2 becomes hot during such motor running. In this case, it is determined in step S106 that the motor MG2 is in a high temperature state. At this time, it is determined whether or not the vehicle speed V is less than the threshold value Vref and the road surface gradient θ exceeds the threshold value θref set as the climbing gradient (step S114). When the vehicle speed is low and the road surface gradient (climbing gradient) is large, the motor MG2 is required to be operated at a low speed and with a high torque, so that there is a possibility that the motor MG2 will be in a high temperature state. Therefore, this determination determines whether or not the motor MG2 is in a state where the high temperature state is likely to continue or become higher. When it is determined in step S114 that the vehicle speed V is equal to or higher than the threshold value Vref or the road surface gradient θ does not exceed the threshold value θref, the process proceeds to step S108, and the motor travel is continued.

  On the other hand, when it is determined in step S114 that the vehicle speed V is less than the threshold value Vref and the road surface gradient θ exceeds the threshold value θref, the engine 22 is started when the engine 22 is stopped (step S116). The value obtained by adding a predetermined value α to the difference between the threshold value Pref and the required power Pe * is added to the current charge request Pb * of the battery 50 to reset the charge request Pb * of the battery 50 (step S118). Using the set charging request Pb * of the battery 50, the required power Pe * is reset according to the equation (1) (step S120). Then, the target rotational speed Ne * and the target torque Te * of the engine 22 are set using the reset required power Pe * (step S122), the processing of steps S124 to S128 is performed, and this routine is ended. Here, the predetermined value α is a conforming value determined as a value equal to or greater than zero so that the overall efficiency is increased in consideration of the energy efficiency of the engine 22 and the charge / discharge efficiency of the battery 50. With such control, the engine 22 can be operated so as to output power that is equal to or higher than the lower limit of the range in which the engine 22 can be efficiently operated, and the battery 50 can be charged with excess power as electric power. Since the charged electric power is later used as driving power, the energy efficiency of the entire vehicle can be improved.

  According to the hybrid vehicle 20 of the embodiment described above, when the motor MG2 is in a high temperature state while the motor is running, the power exceeding the lower limit of the range in which the engine 22 can be efficiently operated is output. In addition to operating the engine 22 and charging the battery 50 with excess power as electric power and using it later as driving power, the engine 22 is simply operated so that the required power Pe * is output. Energy efficiency can be improved. Moreover, since such control is performed based on the vehicle speed V and the road surface gradient θ when the motor MG2 continues to be in a high temperature state or at a higher temperature, the engine 22 can be started more appropriately.

  In the hybrid vehicle 20 of the embodiment, when the motor MG2 reaches a high temperature state while the motor is running, the engine 22 is started based on the vehicle speed V and the road surface gradient θ, but the temperature of the motor MG2 is further increased. The engine 22 may be started based on t. In this case, the engine 22 can be started when the required power Pe * is equal to or higher than a threshold that decreases as the temperature t of the motor MG2 increases. A part of the drive control routine in this case is shown in FIG. This drive control routine is the same as the drive control routine of FIG. 2 except that the processes of steps S130 to S136 are executed instead of the processes of steps S116 to S120 of the drive control routine illustrated in FIG. In the drive control routine of FIG. 6, when the high temperature state of the motor MG2 is determined and the vehicle speed V is less than the threshold value Vref and the road surface gradient θ is greater than the threshold value θref, the threshold value Pref2 tends to decrease as the temperature t of the motor MG2 increases. The threshold value Pref2 is set using a threshold setting map (see, for example, FIG. 7) for setting (Step S130), and the set threshold value Pref2 is compared with the required power Pe * (Step S132). When the required power Pe * is less than the threshold value Pref2, since the power required for the motor MG2 is small, it is determined that no further temperature rise of the motor MG2 occurs, and the motor travel is continued (after step S108). On the other hand, when the required power Pe * is equal to or greater than the threshold value Pref2, the engine 22 is started when the operation of the engine 22 is stopped (step S134), and the lower limit value of the power range in which the engine 22 can be operated relatively efficiently. A predetermined power Pset set in advance as a large power is set as the required power Pe * (step S136), and the processes after step S122 are executed. By such control, the engine 22 can be started more appropriately. Of course, when the engine 22 is started, the operation of the engine 22 is controlled so that a predetermined power Pset that allows the engine 22 to be operated relatively efficiently is output from the engine 22, so that the energy efficiency of the entire vehicle can be improved. . In this modification, when the engine 22 is started, the predetermined power Pset that allows the engine 22 to be operated relatively efficiently is set to the required power Pe *. However, the engine 22 is operated relatively efficiently. Any power can be set as the required power Pe * as long as it can be used.

  In the hybrid vehicle 20 of the embodiment, it is determined whether or not the motor MG2 is in a high temperature state by determining whether or not the temperature t of the motor MG2 is equal to or higher than the threshold value tref, but the temperature t of the motor MG2 is determined. It is also possible to determine whether or not the motor MG2 is in a high temperature state by determining whether or not the temperature t of the motor MG reaches a threshold value or more after a predetermined time based on the rate of change.

  In the hybrid vehicle 20 of the embodiment, even when the motor MG2 reaches a high temperature state while the motor is running, the engine 22 is operated when the vehicle speed V is equal to or higher than the threshold value Vref or the road surface gradient θ is equal to or lower than the threshold value θref of the climbing gradient. Although the motor travel is continued without starting, when the motor MG2 reaches a high temperature during the motor travel, the road surface gradient θ is larger than the threshold θref even if the vehicle speed V is equal to or higher than the threshold Vref. Sometimes the engine 22 may be started, and the engine 22 may be started when the vehicle speed V is less than the threshold value Vref even when the road surface gradient θ is greater than the threshold value θref. Further, when the motor MG2 reaches a high temperature state while the motor is running, the engine 22 may be started immediately regardless of the vehicle speed V or the road surface gradient θ.

  In the hybrid vehicle 20 of the embodiment, when the motor MG2 is in a high temperature state while the motor is running, the engine 22 is operated so as to output power exceeding the lower limit of the range in which the engine 22 can be efficiently operated. However, the power output from the engine 22 may be any power output. Further, the operating point of the engine 22 at that time may be any operating point.

  In the hybrid vehicle 20 of the embodiment, the power of the motor MG2 is shifted by the reduction gear 35 and output to the ring gear shaft 32a. However, as illustrated in the hybrid vehicle 120 of the modified example of FIG. May be connected to an axle (an axle connected to the wheels 64a and 64b in FIG. 8) different from an axle to which the ring gear shaft 32a is connected (an axle to which the drive wheels 63a and 63b are connected).

  In the hybrid vehicle 20 of the embodiment, the power of the engine 22 is output to the ring gear shaft 32a as the drive shaft connected to the drive wheels 63a and 63b via the power distribution and integration mechanism 30, but the modified example of FIG. The hybrid vehicle 220 includes an inner rotor 232 connected to the crankshaft 26 of the engine 22 and an outer rotor 234 connected to a drive shaft that outputs power to the drive wheels 63a and 63b. A counter-rotor motor 230 that transmits a part of the power to the drive shaft and converts the remaining power into electric power may be provided.

  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 is applicable to the automobile industry and the like.

1 is a configuration diagram showing an outline of a configuration of a hybrid vehicle 20 according to an embodiment of the present invention. It is a flowchart which shows an example of the drive control routine performed by the electronic control unit for hybrids 70 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 a mode that an example of the operating line of the engine 22, and target rotational speed Ne * and target torque Te * are set. FIG. 4 is an explanatory diagram showing an example of a collinear diagram for dynamically explaining rotational elements of a power distribution and integration mechanism 30. It is a flowchart which shows an example of the drive control routine performed by the hybrid electronic control unit 70 of the modification. It is explanatory drawing which shows an example of the threshold value Pref setting map. FIG. 11 is a configuration diagram showing an outline of a configuration of a hybrid vehicle 120 according to a modification. FIG. 11 is a configuration diagram showing an outline of a configuration of a hybrid vehicle 220 of a modified example.

Explanation of symbols

20, 120, 220 Hybrid vehicle, 22 engine, 24 engine electronic control unit (engine ECU), 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 inverter, 43, 44 rotational position detection sensor, 45 motor MG2 temperature sensor, 50 battery, 51 battery 50 temperature sensor, 52 for battery Electronic control unit (battery ECU), 54 power line, 60 gear mechanism, 62 differential gear, 63a, 63b, drive wheel, 64a, 64b wheel, 70 hybrid electronic control unit, 72 CPU, 74 ROM, 76 RA , 80 Ignition switch, 81 Shift lever, 82 Shift position sensor, 83 Accelerator pedal, 84 Accelerator pedal position sensor, 85 Brake pedal, 86 Brake pedal position sensor, 88 Vehicle speed sensor, 90 Gradient sensor, 230 Counter rotor motor, 232 Inner rotor 234 Outer rotor, MG1, MG2 motor.

Claims (14)

An internal combustion engine capable of outputting driving power;
An electric motor capable of outputting driving power;
A drive circuit used to drive the electric motor;
Power generation means capable of generating power using at least part of the power from the internal combustion engine;
Power storage means capable of exchanging electric power with the electric motor and the power generation means;
High temperature state detection means for detecting a predetermined high temperature state in the electric motor or the drive circuit;
Required power setting means for setting required power required for the vehicle;
During the predetermined electric running in which the predetermined high temperature state is detected by the high temperature state detection means while running only with the power from the electric motor with the operation of the internal combustion engine stopped based on a predetermined condition, The internal combustion engine is started so that the vehicle travels using the mechanical outputs of the internal combustion engine and the electric motor in parallel by the power based on the set required power by starting the internal combustion engine and the power storage means is charged. Control means for executing high temperature control for controlling the power generation means and the electric motor;
A hybrid car with   2. The hybrid vehicle according to claim 1, wherein the predetermined condition is a condition in which the set required power is less than a predetermined power set as a lower limit value for efficiently operating the internal combustion engine.   The hybrid vehicle according to claim 2, wherein the control means is a means for controlling the internal combustion engine so that power greater than the predetermined power is output from the started internal combustion engine during the predetermined electric driving. A hybrid vehicle according to any one of claims 1 to 3,
Temperature detecting means for detecting the temperature of the electric motor or the drive circuit;
The control means sets a starting power smaller than the predetermined power based on the detected temperature of the electric motor or the drive circuit during the predetermined electric running, and the set required power exceeds the set starting power. A hybrid vehicle that is sometimes means for executing the high temperature control.   The hybrid vehicle according to claim 4, wherein the control means is means for setting the starting power such that the temperature of the electric motor or the drive circuit tends to decrease as the temperature of the electric motor or the drive circuit increases. A hybrid vehicle according to claim 3,
A required power setting means for setting required power to be input to and output from the power storage means based on the state of the power storage means
The required power setting means is means for setting the required power based on the sum of the driving power required for traveling and the required power set by the required power setting means,
In the predetermined electric driving, the control means sets the required power so that the set required power is equal to or higher than the predetermined power instead of setting the required power by the required power setting means. A hybrid vehicle that is a means to execute control. A hybrid vehicle according to any one of claims 1 to 6,
Vehicle speed detection means for detecting the vehicle speed,
The control means is means for executing the high temperature control when the detected vehicle speed is equal to or lower than a predetermined vehicle speed during the predetermined electric running. A hybrid vehicle according to any one of claims 1 to 7,
Road surface gradient detecting means for detecting the road surface gradient,
The control means is means for executing the high temperature control when the detected road gradient is equal to or greater than a predetermined gradient during the predetermined electric driving.   The high temperature state detection means detects the temperature of the electric motor, and when the detected temperature of the electric motor is equal to or higher than a first predetermined temperature or based on the detected temperature of the electric motor and a change in the temperature of the electric motor over time. The hybrid vehicle according to any one of claims 1 to 8, which is means for detecting the predetermined high temperature state when it is estimated that the temperature of the electric motor becomes equal to or higher than a second predetermined temperature within a predetermined time.   The high temperature state detecting means detects the temperature of the drive circuit and when the detected temperature of the drive circuit is equal to or higher than a first predetermined temperature, or the time change of the detected temperature of the drive circuit and the temperature of the drive circuit The hybrid vehicle according to any one of claims 1 to 8, which is means for detecting the predetermined high-temperature state when the temperature of the drive circuit is estimated to be equal to or higher than a second predetermined temperature within a predetermined time based on the above.   The power generation means is connected to an output shaft of the internal combustion engine and a drive shaft connected to an axle, and can output at least part of the power of the internal combustion engine to the drive shaft with input and output of electric power and power. The hybrid vehicle according to claim 1, which is means.   The power generation means is connected to the three shafts of the output shaft of the internal combustion engine, the drive shaft, and the rotation shaft, and power is supplied to the remaining shaft based on power input / output to / from any two of the three shafts. The hybrid vehicle according to claim 11, comprising: a three-shaft power input / output means for inputting / outputting; and a generator capable of inputting / outputting power to / from the rotating shaft.   The power generation means has a first rotor connected to the output shaft of the internal combustion engine and a second rotor connected to the drive shaft, and the first rotor and the second rotation The hybrid vehicle according to claim 11, wherein the hybrid vehicle is a counter-rotor generator rotating by relative rotation with the child. An internal combustion engine capable of outputting power for traveling, an electric motor capable of outputting power for traveling, a drive circuit used for driving the motor, and at least part of the power from the internal combustion engine can generate electric power A control method for a hybrid vehicle comprising: a power generation means; and an electric storage means capable of exchanging electric power with the electric motor and the power generation means,
Detecting a predetermined high temperature state in the electric motor or the drive circuit;
Set the required power required for the vehicle,
During the predetermined electric running in which the predetermined high temperature state is detected by the high temperature state detection means while running only with the power from the electric motor with the operation of the internal combustion engine stopped based on a predetermined condition, The internal combustion engine is started so that the vehicle travels using the mechanical outputs of the internal combustion engine and the electric motor in parallel by the power based on the set required power by starting the internal combustion engine and the power storage means is charged. A hybrid vehicle control method for controlling the power generation means and the electric motor.

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