JP2009255767A - Hybrid vehicle and its control method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To more properly manage a charge storage ratio that is a ratio of a power amount that is dischargeable from an electric storage device, such as, a secondary battery in a hybrid vehicle having an engine and two motors, and to further improve the energy efficiency of the vehicle. <P>SOLUTION: Request power Ped which is requested of the engine is set, based on request torque Tr* requested of a driving axle (S110); target power Pe* is set by multiplying the request power Ped by a correction coefficient kp, based on atmospheric pressure Pa, when the charge storage ratio SOC of the electric storage device is less than a lower limit threshold SL (S140, S160); the target power Pe* is set by multiplying the request power Ped by a correction coefficient kp set to a value of 1.0, regardless of the atmospheric pressure Pa, when the charge storage ratio SOC is the lower limit threshold value SL or above (S150, S160); and the engine and the two motors are controlled (S170-S220), such that the set target power Pe* is outputted from the engine, the request torque Tr* is outputted to the driving axle, and traveling is performed. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

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

Conventionally, this type of hybrid vehicle includes an engine, a first motor that generates power using power from the engine, and a planetary gear mechanism connected to the axle, the output shaft of the engine, and the rotation shaft of the first motor. And a second motor that outputs power to the axle and a battery that exchanges electric power with the first and second motors have been proposed (see, for example, Patent Document 1). In this hybrid vehicle, the target power to be output from the engine is set by multiplying the required power required for the vehicle by a correction coefficient based on the atmospheric pressure, so that the power output from the engine becomes excessive or insufficient due to a change in atmospheric pressure. The charging / discharging by the excessive electric power of the battery based on it is suppressed.
JP 2007-216841 A

  By the way, when a hybrid vehicle such as that described above travels on a highland where the atmospheric pressure is low, it is generally expected that the chance of traveling on a downhill road will increase as compared to when traveling on a flat ground. By regeneratively controlling the motor, the kinetic energy of the vehicle can be recovered and the battery can be charged. However, if charging of the battery is restricted during traveling on a downhill road, the second motor cannot be regeneratively controlled, and the energy efficiency of the hybrid vehicle cannot be improved.

  When the hybrid vehicle of the present invention travels in a low-pressure area such as a high altitude, the energy efficiency of the vehicle can be managed more appropriately by managing the power storage ratio, which is the ratio of the amount of power that can be discharged from a power storage device such as a secondary battery. The main purpose is to further improve

  The hybrid vehicle of the present invention and its control method employ the following means in order to achieve the main object described above.

The hybrid vehicle of the present invention
Connected to an internal combustion engine and a drive shaft connected to an axle, and connected to an output shaft of the internal combustion engine so as to be rotatable independently of the drive shaft, the drive shaft and the output with input and output of electric power and power An electric power input / output means for inputting / outputting power to / from the shaft, an electric motor for inputting / outputting power to / from the drive shaft, and a power storage means capable of exchanging electric power with the electric power / input / output means and the electric motor. A car,
Atmospheric pressure detection means for detecting atmospheric pressure;
A power storage ratio detection means for detecting a power storage ratio that is a ratio of the amount of power that can be discharged from the power storage means;
A required driving force setting means for setting a required driving force required for traveling;
Required power setting means for setting required power to be output from the internal combustion engine based on the set required driving force;
When the detected power storage ratio is less than a predetermined power storage ratio, a correction required power obtained by correcting the set required power by the detected atmospheric pressure is output from the internal combustion engine and the set The internal combustion engine, the electric power drive input / output means, and the electric motor are controlled to run with a driving force based on a required driving force, and when the detected power storage ratio is equal to or higher than the predetermined power storage ratio, the set required power is Control means for controlling the internal combustion engine, the power drive input / output means, and the electric motor so as to travel with a driving force output from the internal combustion engine and based on the set required driving force;
It is a summary to provide.

  In the hybrid vehicle of the present invention, the required power to be output from the internal combustion engine is set based on the required driving force required for traveling, and the power storage ratio that is the ratio of the amount of power that can be discharged from the power storage means is less than the predetermined power storage ratio In such a case, the internal combustion engine, the power power input / output means, and the electric motor are driven so that the corrected required power obtained by correcting the set required power by the atmospheric pressure is output from the internal combustion engine and driven by the driving force based on the required driving force. To control. Thereby, it is possible to suppress an excessive decrease in the power storage ratio during traveling in a region where the atmospheric pressure is low. On the other hand, when the power storage ratio is equal to or higher than the predetermined power storage ratio, the set required power is output from the internal combustion engine, and the internal combustion engine, the power power input / output means, and the electric motor are controlled so as to travel with the driving force based on the required driving force. That is, when the power storage ratio is equal to or higher than the predetermined power storage ratio, the internal combustion engine is configured to output power from the motor by actively using the power from the power storage means without executing correction of the required power of the internal combustion engine by atmospheric pressure. This compensates for the decrease in output power. As a result, it is possible to secure an allowable charging capacity of the power storage means and promote regeneration of the motor on the downhill road when traveling on a highland where the chance of traveling on the downhill road is expected to increase. Therefore, the energy storage ratio, which is the ratio of the amount of power that can be discharged from the power storage device, can be more appropriately managed, and the energy efficiency of the vehicle can be further improved.

  In the hybrid vehicle of the present invention, the predetermined power storage ratio may be a smaller ratio as the detected atmospheric pressure is smaller. In this way, the smaller the atmospheric pressure, the larger the allowable charging capacity of the power storage means can be secured, so that more kinetic energy of the vehicle can be recovered on the subsequent downhill road, and the energy efficiency of the vehicle is further improved. be able to. This is based on the fact that the lower the atmospheric pressure, the higher the position where the vehicle travels and the more descending slopes thereafter.

  In the hybrid vehicle of the present invention, the correction required power is a power that is corrected to tend to increase as the detected atmospheric pressure decreases when the detected atmospheric pressure is less than a predetermined atmospheric pressure. It can also be assumed. In this way, the power storage ratio can be managed more appropriately.

  Furthermore, in the hybrid vehicle according to the present invention, the control means determines that the corrected required power is the internal combustion engine when the set required power is less than the predetermined power even when the detected power storage ratio is equal to or greater than the predetermined power storage ratio. It may be a means for controlling the internal combustion engine, the electric power drive input / output means, and the electric motor so as to run with a driving force that is output from the engine and based on the set required driving force.

  Alternatively, in the hybrid vehicle of the present invention, the power power input / output means is connected to three shafts of a generator that inputs and outputs power, the drive shaft, the output shaft, and the rotating shaft of the generator. 3 axis type power input / output means for inputting / outputting power to / from the remaining shafts based on the power input / output to / from any two axes.

The hybrid vehicle control method of the present invention includes:
Connected to an internal combustion engine and a drive shaft connected to an axle, and connected to an output shaft of the internal combustion engine so as to be rotatable independently of the drive shaft, the drive shaft and the output with input and output of electric power and power An electric power input / output means for inputting / outputting power to / from the shaft, an electric motor for inputting / outputting power to / from the drive shaft, and a power storage means capable of exchanging electric power with the electric power / input / output means and the electric motor. A vehicle control method,
(A) setting a required power to be output from the internal combustion engine based on a required driving force required for traveling;
(B) When the power storage ratio, which is the ratio of the amount of power that can be discharged from the power storage means, is less than a predetermined power storage ratio, a corrected required power obtained by correcting the set required power by atmospheric pressure is output from the internal combustion engine. And controlling the internal combustion engine, the power drive input / output means, and the electric motor so that the vehicle travels with a driving force based on the required driving force, and when the power storage ratio is equal to or higher than the predetermined power storage ratio, the set required power is Controlling the internal combustion engine, the power power input / output means, and the electric motor so as to travel with a driving force based on the required driving force and output from the internal combustion engine;
It is characterized by that.

  In this hybrid vehicle control method of the present invention, the required power to be output from the internal combustion engine is set based on the required driving force required for traveling, and the power storage ratio that is the ratio of the amount of power that can be discharged from the power storage means is predetermined. The internal combustion engine and the power drive input / output means so that the corrected required power obtained by correcting the set required power by the atmospheric pressure is output from the internal combustion engine and the vehicle is driven by the driving force based on the required driving force when the power storage ratio is less than And the motor. Thereby, it is possible to suppress an excessive decrease in the power storage ratio during traveling in a region where the atmospheric pressure is low. On the other hand, when the power storage ratio is equal to or higher than the predetermined power storage ratio, the set required power is output from the internal combustion engine, and the internal combustion engine, the power power input / output means, and the electric motor are controlled so as to travel with the driving force based on the required driving force. That is, when the power storage ratio is equal to or higher than the predetermined power storage ratio, the internal combustion engine is configured to output power from the motor by actively using the power from the power storage means without executing correction of the required power of the internal combustion engine by atmospheric pressure. This compensates for the decrease in output power. As a result, it is possible to secure an allowable charging capacity of the power storage means and promote regeneration of the motor on the downhill road when traveling on a highland where the chance of traveling on the downhill road is expected to increase. Therefore, the energy storage ratio, which is the ratio of the amount of power that can be discharged from the power storage device, can be more appropriately managed, and the energy efficiency of the vehicle can be further 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. The engine electronic control unit (hereinafter referred to as engine ECU) 24 performs fuel injection control, ignition control, and intake air amount adjustment. Under control of operation such as control. The engine ECU 24 receives signals from various sensors that detect the operating state of the engine 22, for example, a crank position from a crank position sensor (not shown) that detects the crank angle of the crankshaft 26 of the engine 22. 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 engine ECU 24 also calculates the rotational speed of the crankshaft 26, that is, the rotational speed Ne of the engine 22, based on a crank position from a crank position sensor (not shown).

  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. 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. The power distribution and integration mechanism 30 includes the motor MG1. 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 detects signals necessary for driving and controlling the motors MG1 and MG2, such as signals from rotational position detection sensors 43 and 44 that detect the rotational positions of the rotors of the motors MG1 and MG2, and current sensors (not shown). The phase current applied to the motors MG1 and MG2 to be applied is input, and a switching control signal to the inverters 41 and 42 is output from the motor ECU 40. 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 motor ECU 40 also calculates the rotational speeds Nm1 and Nm2 of the motors MG1 and MG2 based on signals from the rotational position detection sensors 43 and 44.

  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 Tb from the temperature sensor 51 attached to the battery 50, and the like are input. Output to the control unit 70. In addition, the battery ECU 52 is a power storage ratio that is a ratio of the amount of power that can be discharged to the amount of power when the battery 50 is fully charged, based on the integrated value of the charge / discharge current detected by the current sensor to manage the battery 50. (Remaining capacity) The SOC is calculated, and the input / output limits Win and Wout that are the maximum allowable power that may charge / discharge the battery 50 are calculated based on the calculated storage ratio SOC and the battery temperature Tb. The input / output limits Win and Wout of the battery 50 are set to the basic values of the input / output limits Win and Wout based on the battery temperature Tb, and the output limiting correction coefficient and the input limiting limit are set based on the storage ratio SOC of the battery 50. It can be set by setting a correction coefficient and multiplying the basic value of the set input / output limits Win and Wout by the correction coefficient.

  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 atmospheric pressure Pa from the atmospheric pressure sensor 89, etc. Is entered through. 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 the 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 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 so as 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 hybrid vehicle 20 of the embodiment configured as described above, particularly the operation when traveling in a low-pressure area such as a high altitude 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 vehicle speed V from the vehicle speed sensor 88, the rotational speed Nm1, of the motors MG1, MG2. A process of inputting data required for control, such as Nm2, the storage ratio SOC of the battery 50, the output limit Wout of the battery 50, and the atmospheric pressure Pa from the atmospheric pressure sensor 89, is executed (step S100). Here, the rotational speeds Nm1 and Nm2 of the motors MG1 and MG2 are calculated based on the rotational positions of the motors MG1 and MG2 and input from the motor ECU 40 by communication. The storage ratio SOC and output limit Wout of the battery 50 are set based on the integrated value of the charge / discharge current of the battery 50, and calculated based on the battery temperature Tb of the battery 50 and the storage ratio SOC. Are input from the battery ECU 52 by communication.

  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 Ped required for the engine 22 is set (step S110). 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 vehicle speed V, the accelerator opening Acc, , 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 Ped can be calculated as the sum of the set required torque Tr * multiplied by the rotational speed Nr of the ring gear shaft 32a and the required charge / discharge power Pb * to be charged / discharged to the battery 50 and the loss Loss. The rotational speed Nr of the ring gear shaft 32a is obtained by multiplying the vehicle speed V by a conversion factor k (Nr = k · V), or the rotational speed Nm2 of the motor MG2 is divided by the gear ratio Gr of the reduction gear 35 (Nr = Nm2 / Gr).

  Next, the lower limit threshold SL for the storage ratio SOC of the battery 50 is set based on the atmospheric pressure Pa (step S120), and compared with the lower limit threshold SL that sets the storage ratio SOC of the battery 50 (step S130). An example of the relationship between the atmospheric pressure Pa and the lower limit threshold SL is shown in FIG. As shown in the figure, the lower limit threshold SL is set to a target storage ratio SOC * as a control center set by a setting process (not shown) in an area where the atmospheric pressure Pa is equal to or higher than the standard pressure Pnml (for example, 1 atmosphere). The value Smin is set to a constant value in the region below the value PLo, which is a relatively low value, and the value Smin from the target power storage ratio SOC * decreases as the atmospheric pressure Pa decreases in the region where the atmospheric pressure Pa is less than the standard pressure Pnml and above the value Plo. A value that gradually decreases toward is set. Here, as the value Smin, for example, a value slightly larger than the power storage ratio at which the battery 50 is overdischarged can be used, and as the target power storage ratio SOC *, for example, 50% or 60% is set.

  When the storage ratio SOC is less than the lower limit threshold SL, the correction coefficient kp is set based on the atmospheric pressure Pa (step S140). When the storage ratio SOC is equal to or higher than the lower limit threshold SL, the correction coefficient kp is set regardless of the atmospheric pressure Pa. 1.0 is set (step S150), and the target power Pe * of the engine 22 is set by multiplying the required power Ped by the set correction coefficient kp (step S160). An example of the relationship between the atmospheric pressure Pa and the correction coefficient kp when the power storage rate SOC is less than the lower limit threshold SL is shown in FIG. As shown in the figure, the correction coefficient kp when the power storage ratio SOC is less than the lower limit threshold SL is set to a constant value 1.0 in a region where the atmospheric pressure Pa is equal to or higher than the standard pressure Pnml (for example, 1 atmosphere). In a region where the pressure is less than the standard pressure Pnml, a larger value is set as the atmospheric pressure Pa is smaller. Thereby, when the storage ratio SOC is less than the lower limit threshold SL, the target power Pe * of the engine 22 set by multiplying the required power Ped by the correction coefficient kp is the required power Ped in the region where the atmospheric pressure Pa is equal to or higher than the standard pressure Pnml. In a region where the atmospheric pressure Pa is less than the standard pressure Pnml, the smaller the atmospheric pressure Pa, the larger the required power Ped. On the other hand, when the power storage rate SOC is equal to or higher than the lower limit threshold SL, the target power Pe * matches the required power Ped regardless of the atmospheric pressure Pa.

  Subsequently, the target rotational speed Ne * and the target torque Te * are set as operating points at which the engine 22 should be operated based on the set target power Pe * (step S170). This setting is performed based on the operation line for efficiently operating the engine 22 and the target power Pe *. FIG. 6 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 *).

  Next, using the target rotational speed Ne * of the engine 22, the rotational speed Nm2 of the motor MG2, the gear ratio ρ of the power distribution and integration mechanism 30, and the gear ratio Gr of the reduction gear 35, the target of the motor MG1 is expressed by the following equation (1). Formula (2) is calculated based on the calculated target rotational speed Nm1 *, the input rotational speed Nm1 of the motor MG1, the target torque Te * of the engine 22, and the gear ratio ρ of the power distribution and integration mechanism 30. To calculate the torque command Tm1 * of the motor MG1 (step S180). Here, Expression (1) is a dynamic relational expression for the rotating element of the power distribution and integration mechanism 30. FIG. 7 is a collinear diagram showing a dynamic relationship between the rotational speed and torque in the rotating elements of the power distribution and integration mechanism 30 when traveling with the power output from the engine 22. 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 dividing the number Nm2 by the gear ratio Gr of the reduction gear 35 is shown. Equation (1) can be easily derived by using this alignment chart. The two thick arrows on the R axis indicate the torque that the torque Tm1 output from the motor MG1 acts on the ring gear 32a, and the torque that the torque output from the motor MG2 acts on the ring gear shaft 32a via the reduction gear 35. Indicates. Expression (2) is a relational expression in feedback control for rotating the motor MG1 at the target rotational speed Nm1 *. In Expression (2), “k1” in the second term on the right side is a gain of a 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) (1)
Tm1 * =-ρ ・ Te * / (1 + ρ) + k1 (Nm1 * -Nm1) + k2∫ (Nm1 * -Nm1) dt (2)

  Then, the torque command Tm1 * set as the required torque Tr * is divided by the gear ratio ρ of the power distribution and integration mechanism 30 and further divided by the gear ratio Gr of the reduction gear 35 to obtain the torque to be output from the motor MG2. A temporary torque Tm2tmp, which is a temporary value, is calculated by the following equation (3) (step S190), and is obtained by multiplying the output limit Wout of the battery 50 and the set torque command Tm1 * by the current rotational speed Nm1 of the motor MG1. A torque limit Tm2max as an upper limit of the torque that may be output from the motor MG2 by dividing the deviation from the power consumption (generated power) of the motor MG1 by the rotation speed Nm2 of the motor MG2 is calculated by the following equation (4) (step) S200), the set temporary torque Tm2tmp is limited by the torque limit Tm2max, and the torque command Tm2 * of the motor MG2 is set. Set (step S210). Here, Expression (3) can be easily derived from the alignment chart of FIG.

Tm2tmp = (Tr * + Tm1 * / ρ) / Gr (3)
Tm2max = (Wout-Tm1 * ・ Nm1) / Nm2 (4)

  Thus, when the target engine speed Ne *, the target torque Te *, and the torque commands Tm1 *, Tm2 * of the motors MG1, MG2 are set, the target engine speed Ne * and the target torque Te * of the engine 22 are set in the engine ECU 24. The torque commands Tm1 * and Tm2 * for the motors MG1 and MG2 are transmitted to the motor ECU 40 (step S220), and the drive control routine is terminated. The engine ECU 24 that has received the target rotational speed Ne * and the target torque Te * controls the intake air amount in the engine 22 so that the engine 22 is operated at the operating point indicated by the target rotational speed Ne * and the target torque Te *. Controls such as fuel injection control and ignition control. Further, 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. By such control, the engine 22 can be efficiently operated within the range of the input / output limits Win and Wout of the battery 50, and the required torque Tr * can be output to the ring gear shaft 32a as a drive shaft to travel.

  Here, when the atmospheric pressure Pa is the standard pressure Pnml, the intake air amount control or fuel injection control of the engine 22 is performed so that the power Pe output from the engine 22 (hereinafter referred to as engine power) Pe becomes the target power Pe *. When the atmospheric pressure Pa is relatively low, the engine power Pe is less than the target power Pe * because the amount of oxygen sucked into the combustion chamber is reduced due to a decrease in the air density sucked into the engine 22 when the atmospheric pressure Pa is relatively small. It will be smaller. In this case, compared to when the target power Pe * is output as the engine power Pe, the torque command Tm1 * of the motor MG1 calculated to rotate the motor MG1 at the target rotational speed Nm1 * by the above-described equation (2). Increases (the torque for power generation decreases), and the temporary torque Tm2tmp of the motor MG2 calculated by the equation (3) using the torque command Tm1 * increases. Therefore, compared to when target power Pe * is output as engine power Pe, the electric power generated by motor MG1 becomes smaller and the electric power consumed by motor MG2 becomes larger. Is assumed to be on the discharge side from the required charge / discharge power Pb *. Considering this, in the embodiment, when the storage ratio SOC of the battery 50 is less than the lower limit threshold SL, the target power Pe * is set by multiplying the required power Ped by a correction coefficient kp that tends to increase as the atmospheric pressure Pa decreases. To do. As a result, the engine power Pe can be made closer to the required power Ped, and it is possible to suppress an excessive decrease in the storage ratio SOC of the battery 50 when traveling in an area where the atmospheric pressure is low such as a high altitude.

  Further, when traveling in an area where the atmospheric pressure Pa is relatively small, such as a highland, the chance of traveling on a downhill road is generally increased as compared to traveling on a flat ground, and it is expected that the road will travel downhill. Then, on the downhill road, the motor MG2 is regeneratively controlled to recover the kinetic energy of the vehicle and charge the battery 50. For this reason, in the embodiment, when the power storage rate SOC is equal to or higher than the lower limit threshold SL, the correction coefficient kp is set to a value 1.0 regardless of the atmospheric pressure Pa so that more kinetic energy of the vehicle can be recovered on such downhill roads. The power from the battery 50 is actively used to output power from the motor MG2 to compensate for the decrease in engine power Pe. Thereby, when the power storage rate SOC is equal to or greater than the lower limit threshold SL, as described above, when the power input / output to / from the battery 50 is on the discharge side from the charge / discharge required power Pb *, the power storage rate SOC gradually decreases. The allowable charging capacity of the battery 50 for recovering the kinetic energy of the vehicle can be ensured. Therefore, by such control, it is possible to suppress the charging of the battery 50 from being restricted due to the large storage ratio SOC when traveling at a high altitude where an opportunity to travel on the downhill road is expected to increase. It becomes possible to promote regeneration of motor MG2.

  Furthermore, the higher the altitude of the position where the vehicle is traveling, the more descending slopes are expected thereafter, and the motor MG2 is expected to increase the power recovered by regenerative control. As shown in FIG. 3, the lower limit threshold SL is set to be smaller as the atmospheric pressure Pa is smaller. That is, the higher the altitude at which the vehicle travels, the greater the chance of traveling on the downhill road and the greater the amount of vehicle kinetic energy that can be recovered, so the lower limit threshold SL is set to a small value and the battery 50 is allowed. A larger charge capacity is ensured. Thereby, the allowable charge capacity of the battery 50 can be ensured according to the atmospheric pressure Pa, that is, the altitude of the position where the vehicle travels, and the energy efficiency of the vehicle can be further improved.

  According to the hybrid vehicle 20 of the embodiment described above, the required power Ped required for the engine 22 is set based on the required torque Tr * required for the ring gear shaft 32a as the drive shaft, and the power storage rate SOC of the battery 50 is set. Is less than the lower limit threshold SL, the target power Pe * obtained by multiplying the required power Ped by the correction coefficient kp based on the atmospheric pressure Pa is output from the engine 22, and the required driving force Tr * is output to the ring gear shaft 32a. Since the engine 22 and the motors MG1 and MG2 are controlled as described above, it is possible to suppress an excessive decrease in the storage rate SOC during traveling in a region where the atmospheric pressure is low. On the other hand, when the storage ratio SOC is equal to or greater than the lower limit threshold SL, the target power Pe * obtained by multiplying the required power Ped by a correction coefficient kp that is set to a value 1.0 regardless of the atmospheric pressure Pa is output from the engine 22 and the ring gear. Since the engine 22 and the motors MG1 and MG2 are controlled so as to travel by outputting the required driving force Tr * to the shaft 32a, the battery 50 is allowed to travel at high altitudes where the chance of traveling downhill is expected to increase. It is possible to secure the charging capacity and promote the regeneration of the motor MG2 on the downhill road. Therefore, it is possible to more appropriately manage the power storage ratio SOC and further improve the energy efficiency of the vehicle.

  In the hybrid vehicle 20 of the embodiment, the lower limit threshold SL is set based on the atmospheric pressure Pa, but instead of or in addition to this, in the vehicle that can receive the traveling position from the GPS satellite, the received traveling It may be set using the altitude at which the vehicle detected based on the position and map information is located, or in a vehicle equipped with a road surface gradient sensor, it is calculated based on the detected road surface gradient θ and vehicle speed V, etc. It may be set using the altitude at which the vehicle is calculated by integrating the amount of change in altitude at which the vehicle is positioned. The lower limit threshold SL may be set based on the amount of change of such data in a predetermined time. In this case, the lower limit threshold SL may be set every predetermined time based on the value based on such a change amount and the previous lower limit threshold SL. Furthermore, the lower limit threshold SL may be set to a fixed value regardless of such data.

  In the hybrid vehicle 20 of the embodiment, when the storage ratio SOC of the battery 50 is equal to or higher than the lower limit threshold SL, the correction coefficient kp is set to a constant value 1.0, but the storage ratio SOC is equal to or higher than the lower limit threshold SL. Alternatively, when the required power Ped of the engine 22 is less than the threshold value Pref, the correction coefficient kp may be set based on the atmospheric pressure Pa and the correction coefficient setting map of FIG. That is, even if the power storage ratio SOC is equal to or greater than the lower limit threshold SL, when the required power Ped of the engine 22 is less than the threshold Pref, the target power Pe * of the engine 22 may be set by performing correction based on the atmospheric pressure Pa. Absent. By so doing, it is possible to suppress problems that occur when the atmospheric pressure Pa is small and the required power Ped to be output from the engine 22 is small (for example, poor combustion).

  In the hybrid vehicle 20 of the embodiment, when the storage ratio SOC of the battery 50 is less than the lower threshold SL, and when the atmospheric pressure Pa is less than the standard pressure Pnml, the correction coefficient kp is set to a larger value as the atmospheric pressure Pa is smaller. However, when the atmospheric pressure Pa is less than the standard pressure Pnml, the correction coefficient kp may be set to a fixed value greater than 1.0 regardless of the atmospheric pressure Pa.

  In the hybrid vehicle 20 of the embodiment, the motor MG2 is attached to the ring gear shaft 32a as the drive shaft via the reduction gear 35. However, the motor MG2 may be directly attached to the ring gear shaft 32a, or Instead, the motor MG2 may be attached to the ring gear shaft 32a via a transmission such as a 2-speed, 3-speed, or 4-speed.

  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 output 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.

  Further, in the present embodiment, the content of the present invention has been described as the hybrid vehicle 20, but such a hybrid vehicle control method may be employed.

  Here, the correspondence between the main elements of the embodiments and the modified examples and the main elements of the invention described in the column of means for solving the problems will be described. In the embodiment, the engine 22 corresponds to an “internal combustion engine”, the power distribution and integration mechanism 30 and the motor MG1 correspond to “power power input / output means”, the motor MG2 corresponds to “electric motor”, and the battery 50 corresponds to “ “Atmospheric pressure sensor 89” corresponds to “atmospheric pressure detection means” and the battery 50 is fully charged with the amount of electric power that can be discharged based on the integrated value of the charge / discharge current detected by the current sensor. Step S110 of the drive control routine of FIG. 2 in which the battery ECU 52 for calculating the storage ratio SOC, which is a ratio to the above, corresponds to the “storage ratio detection means” and sets the required torque Tr * based on the accelerator opening Acc and the vehicle speed V. The hybrid electronic control unit 70 that executes the above process corresponds to “required driving force setting means”, and the required torque Tr * is multiplied by the rotational speed Nr of the ring gear shaft 32a. The hybrid electronic control unit 70 that executes the processing of step S110 of the drive control routine of FIG. 2 that sets the required power Ped as the sum of the charge, the required charge / discharge power Pb *, and the loss Loss becomes the “required power setting means”. The target power Pe * is set by multiplying the required power Ped by the correction coefficient kp based on the atmospheric pressure Pa when the storage ratio SOC of the battery 50 is less than the lower limit threshold SL, and required when the storage ratio SOC is greater than or equal to the lower limit threshold SL. The target power Pe * is set by multiplying the power Ped by a correction coefficient kp that is set to a value of 1.0 regardless of the atmospheric pressure Pa. The set target power Pe * is output from the engine 22 and the required driving force Tr *. Sets the target rotational speed Ne * and the target torque Te * of the engine 22 so that the vehicle travels by acting on the ring gear shaft 32a. The hybrid electronic control unit 70 for executing the processing of steps S130 to S220 of the drive control routine of FIG. 2 for setting torque commands Tm1 * and Tm2 * of the motors MG1 and MG2 and transmitting them to the engine ECU 24 and the motor ECU 40 together with the target rotation. The engine ECU 24 that controls the engine 22 based on the number Ne * and the target torque Te * and the motor ECU 40 that controls the motors MG1 and MG2 based on the torque commands Tm1 * and Tm2 * correspond to “control means”. Further, the motor MG1 corresponds to a “generator”, and the power distribution and integration mechanism 30 corresponds to a “3-axis power input / output unit”. Further, the counter-rotor motor 230 also corresponds to “power power input / output means”.

  Here, the “internal combustion engine” is not limited to an internal combustion engine that outputs power using a hydrocarbon fuel such as gasoline or light oil, and may be any type of internal combustion engine such as a hydrogen engine. The “power power input / output means” is not limited to the combination of the power distribution and integration mechanism 30 and the motor MG1 or the counter-rotor motor 230, and is connected to the drive shaft connected to the axle. As long as it is connected to the output shaft of the internal combustion engine so as to be able to rotate independently of the drive shaft, and can input and output power to and from the drive shaft and output shaft together with input and output of electric power and power, it may be anything. . The “motor” is not limited to the motor MG2 configured as a synchronous generator motor, and may be any type of motor as long as it can input and output power to the drive shaft, such as an induction motor. . The “storage means” is not limited to the battery 50 as a secondary battery, and may be anything as long as it can exchange power with a power motive power input / output means or an electric motor such as a capacitor. The “atmospheric pressure detecting means” is not limited to the atmospheric pressure sensor 89, and any means that detects atmospheric pressure may be used. The “power storage ratio detection means” is not limited to the one that calculates the power storage ratio SOC based on the integrated value of the charge / discharge current detected by the current sensor. For example, based on the voltage between the terminals of the power storage means. It may be detected, and any device may be used as long as it can detect a power storage ratio that is a ratio of the amount of power that can be discharged from the power storage means. The “required driving force setting means” is not limited to the one that sets the required torque Tr * based on the accelerator opening Acc and the vehicle speed V, but sets the required torque based only on the accelerator opening Acc. If the required driving force required for traveling is set, such as those for which the required torque is set based on the traveling position on the traveling route, such as those for which the driving route is set in advance I do not care. The “required power setting means” is limited to a device that sets the required power Ped as the sum of the required torque Tr * multiplied by the rotation speed Nr of the ring gear shaft 32a and the charge / discharge required power Pb * and the loss Loss. It does not matter as long as it sets the required power to be output from the internal combustion engine based on the set required driving force. The “control means” is not limited to the combination of the hybrid electronic control unit 70, the engine ECU 24, and the motor ECU 40, and may be configured by a single electronic control unit. Further, as the “control means”, when the storage ratio SOC of the battery 50 is less than the lower limit threshold SL, the target power Pe * is set by multiplying the required power Ped by the correction coefficient kp based on the atmospheric pressure Pa, and the storage ratio SOC is the lower limit. When the value is equal to or greater than the threshold value SL, the target power Pe * is set by multiplying the required power Ped by a correction coefficient kp that is set to a value of 1.0 regardless of the atmospheric pressure Pa, and the set target power Pe * is output from the engine 22. In addition, it is not limited to controlling the engine 22 and the motors MG1 and MG2 so that the required driving force Tr * acts on the ring gear shaft 32a and travels. When the ratio is less than the specified power storage ratio, the corrected required power obtained by correcting the set required power with atmospheric pressure is output from the internal combustion engine. The internal combustion engine, the power drive input / output means and the motor are controlled so that the vehicle travels with a driving force based on the required driving force. When the storage ratio is equal to or higher than the predetermined storage ratio, the set required power is output from the internal combustion engine and requested. Any device may be used as long as it controls the internal combustion engine, the electric power drive input / output means, and the electric motor so as to travel with the driving force based on the driving force. The “generator” is not limited to the motor MG1 configured as a synchronous generator motor, and may be any type of generator such as an induction motor that can input and output power. The “three-axis power input / output means” is not limited to the power distribution / integration mechanism 30 described above, but includes four or more shafts using a double pinion type planetary gear mechanism or a combination of a plurality of planetary gear mechanisms. Any one of the three axes connected to the three axes of the drive shaft, the output shaft, and the rotating shaft of the generator, such as those connected to the motor and those having a different operation action from the planetary gear such as a differential gear As long as the power is input / output to / from the remaining shafts based on the power input / output to / from the power source, any method may be used.

  Note that the correspondence between the main elements of the embodiment and the modified example and the main elements of the invention described in the column of means for solving the problem is described in the column of means for the embodiment to solve the problem. Since this is an example for specifically describing the best mode for carrying out the invention, the elements of the invention described in the column of means for solving the problems are not limited. That is, the interpretation of the invention described in the column of means for solving the problems should be made based on the description of the column, and the examples are those of the invention described in the column of means for solving the problems. It is only a specific example.

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

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

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 which shows an example of the relationship between atmospheric pressure Pa and lower limit threshold value SL. It is explanatory drawing which shows an example of the relationship between atmospheric pressure Pa and the correction coefficient kp. It is explanatory drawing which shows a mode that an example of the operating line of the engine 22, the target rotational speed Ne *, and the target torque Te * are set. FIG. 6 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 when traveling with power output from the engine 22; 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, 50 battery, 51 temperature sensor, 52 battery electronic control unit (battery ECU), 54 power line , 60 gear mechanism, 62 differential gear, 63a, 63b drive wheel, 64a, 64b wheel, 70 electronic control unit for hybrid, 72 CPU, 74 ROM, 76 RAM, 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, 89 atmospheric pressure sensor, 230 rotor motor, 232 inner rotor, 234 outer Rotor, MG1, MG2 motor.

Claims (5)

Connected to an internal combustion engine and a drive shaft connected to an axle, and connected to an output shaft of the internal combustion engine so as to be rotatable independently of the drive shaft, the drive shaft and the output with input and output of electric power and power An electric power input / output means for inputting / outputting power to / from the shaft, an electric motor for inputting / outputting power to / from the drive shaft, and a power storage means capable of exchanging electric power with the electric power / input / output means and the electric motor. A car,
Atmospheric pressure detection means for detecting atmospheric pressure;
A power storage ratio detection means for detecting a power storage ratio that is a ratio of the amount of power that can be discharged from the power storage means;
A required driving force setting means for setting a required driving force required for traveling;
Required power setting means for setting required power to be output from the internal combustion engine based on the set required driving force;
When the detected power storage ratio is less than a predetermined power storage ratio, a correction required power obtained by correcting the set required power by the detected atmospheric pressure is output from the internal combustion engine and the set The internal combustion engine, the electric power drive input / output means, and the electric motor are controlled to run with a driving force based on a required driving force, and when the detected power storage ratio is equal to or higher than the predetermined power storage ratio, the set required power is Control means for controlling the internal combustion engine, the power power input / output means, and the electric motor so as to travel with a driving force output from the internal combustion engine and based on the set required driving force;
A hybrid car with   The hybrid vehicle according to claim 1, wherein the predetermined power storage ratio is a smaller ratio as the detected atmospheric pressure is smaller.   The correction required power is a power that is corrected such that when the detected atmospheric pressure is less than a predetermined atmospheric pressure, the corrected atmospheric power becomes larger as the detected atmospheric pressure is smaller. Hybrid car.   The control means outputs the correction request power from the internal combustion engine and sets the power when the set required power is less than the predetermined power even when the detected power storage ratio is equal to or greater than the predetermined power storage ratio. The hybrid vehicle according to any one of claims 1 to 3, which is means for controlling the internal combustion engine, the electric power drive input / output means, and the electric motor so as to travel with a driving force based on the requested driving force. Connected to an internal combustion engine and a drive shaft connected to an axle, and connected to an output shaft of the internal combustion engine so as to be rotatable independently of the drive shaft, the drive shaft and the output with input and output of electric power and power An electric power input / output means for inputting / outputting power to / from the shaft, an electric motor for inputting / outputting power to / from the drive shaft, and a power storage means capable of exchanging electric power with the electric power / input / output means and the electric motor. A vehicle control method,
(A) setting a required power to be output from the internal combustion engine based on a required driving force required for traveling;
(B) When the power storage ratio, which is the ratio of the amount of power that can be discharged from the power storage means, is less than a predetermined power storage ratio, a corrected required power obtained by correcting the set required power by atmospheric pressure is output from the internal combustion engine. And controlling the internal combustion engine, the power drive input / output means, and the electric motor so that the vehicle travels with a driving force based on the required driving force, and when the power storage ratio is equal to or higher than the predetermined power storage ratio, the set required power is Controlling the internal combustion engine, the power power input / output means, and the electric motor so as to travel with a driving force based on the required driving force and output from the internal combustion engine;
Control method of hybrid vehicle.

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