JP2009023527A - Vehicle and control method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent a driver from feeling discomfort when running backward on an uphill road, in a vehicle in which a sun gear, a carrier, and a ring gear of a planetary gear mechanism are connected with a first motor, an engine, an axle, and a second motor. <P>SOLUTION: When the vehicle runs backward on an uphill road in a reverse direction, during an engine stop, output limit "Wout" is set to have tendency to be smaller on the uphill road than on a non-uphill road by considering road gradient θ (S130, S140), and the second motor is controlled using the output limit "Wout" and requested torque "Tr*" (S150 to S200). When running backward during a load operation of the engine, the output limit "Wout" is set without considering the road gradient θ (S230), while the engine and two motors are controlled using the output limit "Wout" and the requested torque "Tr*" (S240 to S260, S170 to S200). <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a vehicle and a control method therefor, and more particularly, is connected to an internal combustion engine and a drive shaft coupled to an axle and is connected to an output shaft of the internal combustion engine so as to be rotatable independently of the drive shaft. And power input / output means for outputting at least part of the power from the output shaft to the drive shaft as power in the forward direction with power input and output, and an electric motor capable of outputting power to the axle And a control method thereof.

Conventionally, as this type of vehicle, a vehicle including an engine, a motor generator, a planetary gear device connected to the engine and the motor generator and outputting power to the front wheels, and a rear motor generator has been proposed ( For example, see Patent Document 1). In this vehicle, when the vehicle travels backward, the front wheels are driven by torque from the motor generator or engine via the double pinion planetary gear unit and continuously variable transmission by turning on and off the brake and the two clutches. Can be communicated to. Until the front wheels slip, the output torque from the rear motor generator connected to the rear wheels is limited more than usual, so that the distance traveled in the four-wheel drive state when traveling backward on an uphill road Is trying to get longer.
JP 2004-166383 A

  By the way, in a vehicle including a planetary gear device that outputs power from an engine to a drive wheel as power in a forward direction with power generation of a motor generator, and a traveling motor connected to the drive wheel, only the power from the motor is used. During reverse travel, if the remaining capacity of the battery or other power storage device decreases and the engine is loaded and power is generated by the motor generator, the power from the engine is output to the drive wheels as power in the forward direction. Therefore, a part of the reverse direction power output from the travel motor is canceled out by the forward power from the engine, and the maximum driving force that can be used for reverse travel decreases. When traveling backward on an uphill road, it is desirable not to give the driver an uncomfortable feeling in consideration of a change in the maximum driving force depending on whether or not the engine is loaded.

  A vehicle and a control method thereof according to the present invention include an electric power drive input / output device that outputs at least a part of power from an output shaft of an internal combustion engine to a drive shaft as power in a forward direction with input and output of electric power and power. The main object of the present invention is to prevent the driver from feeling uncomfortable when traveling backward on an uphill road.

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

The vehicle of the present invention
Power from the output shaft connected to the internal combustion engine and a drive shaft connected to the axle and connected to the output shaft of the internal combustion engine so as to be able to rotate independently of the drive shaft and with input and output of electric power and power A power motive power input / output means for outputting at least a part of the power to the drive shaft as power in the forward direction, and an electric motor capable of outputting power to the axle,
A power storage means capable of exchanging power with the electric power drive input / output means and the electric motor;
A remaining capacity detecting means for detecting a remaining capacity, which is an amount of power that can be discharged from the power storage means;
Road surface gradient detecting means for detecting the road surface gradient;
When traveling backward, based on the detected remaining capacity and the detected road surface gradient, when the road surface gradient is an uphill gradient in the reverse direction and the road surface gradient is not an uphill gradient in the reverse direction Output limit setting means for setting an output limit that is the maximum power allowed to discharge from the power storage means in a tendency to be smaller than
A required driving force setting means for setting a required driving force required for traveling;
When the vehicle travels in reverse, the output limit is set within the set output limit with the load operation of the internal combustion engine due to the establishment of a load condition where one of the conditions is that the detected remaining capacity reaches a predetermined remaining capacity or less. Control means for controlling the internal combustion engine, the power drive input / output means, and the electric motor so as to travel with a set required driving force;
It is a summary to provide.

  In the vehicle of the present invention, when traveling backward, compared to the case where the road surface gradient is an uphill gradient in the reverse direction based on the remaining capacity, which is the amount of power that can be discharged from the power storage means, and the road surface gradient, Therefore, the load on the internal combustion engine due to the establishment of a load condition that sets the output limit, which is the maximum power allowed to be discharged from the power storage means, and the remaining capacity reaches a predetermined remaining capacity or less. The internal combustion engine, the power power input / output means, and the electric motor are controlled so as to travel with the required driving force required for traveling within the range of the output restriction with operation. That is, when traveling backward on an uphill road with respect to the reverse direction, the internal combustion engine, the power power input / output means, and the electric motor are controlled using a smaller output restriction than when the road is not uphill, and the vehicle is driven with the required driving force. . Therefore, when driving the internal combustion engine under load operation and outputting power in the reverse direction with power generation by the power power input / output means and driving of the electric motor using the generated power, when traveling backward on the uphill road, The maximum driving force that can be output in the reverse direction when the internal combustion engine is not loaded is limited as compared with the case where a relatively large output limit is set without considering the road gradient. The difference in the maximum driving force that can be output in the reverse direction depending on whether or not the internal combustion engine is under load operation can be reduced as compared with a case that is not considered. Thereby, it can suppress that the driving force to a reverse drive direction changes greatly by whether the internal combustion engine is carrying out load operation, and it can suppress giving a driver uncomfortable feeling.

  In such a vehicle of the present invention, the output restriction setting means may be means for setting the output restriction so that the detected road surface gradient tends to decrease as the climbing gradient in the reverse direction increases. In this way, it is possible to set an output limit that more reflects the road surface gradient.

  Further, in the vehicle of the present invention, the output restriction setting means is configured to perform the operation based on the detected remaining capacity regardless of the detected road surface gradient when the internal combustion engine is loaded with the load condition being satisfied. It can also be a means for setting an output limit.

  Further, in the vehicle of the present invention, the power storage means is a lithium ion secondary battery, and the output limit setting means is a means for setting the output limit so that the larger the discharge current from the power storage means, the smaller the current is. It can also be. This is based on the reason for suppressing deterioration of the lithium ion secondary battery.

  Alternatively, in the vehicle according to the present invention, the power power input / output means is connected to three shafts of a generator for inputting / outputting power, the drive shaft, the output shaft, and the rotating shaft of the generator. It can also be a means provided with three-axis type power input / output means for inputting / outputting power to / from the remaining shafts based on power input / output to / from any two axes.

The vehicle control method of the present invention includes:
Power from the output shaft connected to the internal combustion engine and a drive shaft connected to the axle and connected to the output shaft of the internal combustion engine so as to be able to rotate independently of the drive shaft and with input and output of electric power and power Power motive power input / output means that outputs at least a part of the power to the drive shaft as power in the forward direction, an electric motor that can output power to the axle, and an electric storage that can exchange electric power with the power motive power input / output means and the motor A vehicle control method comprising:
When traveling backward, based on the remaining capacity, which is the amount of power that can be discharged from the power storage means, and the road surface gradient, the road surface gradient is an uphill gradient in the reverse direction when the road surface gradient is an uphill gradient in the reverse direction. Is set to an output limit that is the maximum power that is allowed to be discharged from the power storage means, and the remaining capacity is one of the conditions that the remaining capacity falls below a predetermined remaining capacity. Controlling the internal combustion engine, the power power input / output means, and the electric motor so as to travel with the required driving force required for traveling within the set output limit range with the load operation of the internal combustion engine due to establishment.
It is characterized by that.

  In the vehicle control method according to the present invention, when the vehicle travels in reverse, it is not an uphill gradient when the road surface gradient is an uphill gradient in the reverse direction based on the remaining capacity and the road surface gradient, which is the amount of power that can be discharged from the power storage means. Internal combustion due to the establishment of a load condition where one of the conditions is that the output limit is set to the maximum power allowed to be discharged from the power storage means, and the remaining capacity is less than or equal to a predetermined remaining capacity. The internal combustion engine, the power power input / output means, and the electric motor are controlled so as to travel with the required driving force required for traveling within the range of output restriction with the load operation of the engine. That is, when traveling backward on an uphill road with respect to the reverse direction, the internal combustion engine, the power power input / output means, and the electric motor are controlled using a smaller output restriction than when the road is not uphill, and the vehicle is driven with the required driving force. . Therefore, when driving the internal combustion engine under load operation and outputting power in the reverse direction with power generation by the power power input / output means and driving of the electric motor using the generated power, when traveling backward on the uphill road, The maximum driving force that can be output in the reverse direction when the internal combustion engine is not loaded is limited as compared with the case where a relatively large output limit is set without considering the road gradient. The difference in the maximum driving force that can be output in the reverse direction depending on whether or not the internal combustion engine is under load operation can be reduced as compared with a case that is not considered. Thereby, it can suppress that the driving force to a reverse drive direction changes greatly by whether the internal combustion engine is carrying out load operation, and it can suppress giving a driver uncomfortable feeling.

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

  FIG. 1 is a configuration diagram showing an outline of a configuration of a hybrid vehicle 20 equipped with a power output apparatus 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 power output apparatus.

  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. 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 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 configured as a lithium ion secondary battery, for example, and 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, an inter-terminal voltage Vb from the voltage sensor 51 a installed between the terminals of the battery 50, and a power line 54 connected to the output terminal of the battery 50. The charging / discharging current Ib from the attached current sensor 51b, the battery temperature Tb from the temperature sensor 51c attached to the battery 50, and the like are input. Output to the control unit 70. Further, the battery ECU 52 calculates the remaining capacity SOC based on the integrated value of the charge / discharge current Ib detected by the current sensor 51b 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 opening Acc from the vehicle, the brake pedal position BP from the brake pedal position sensor 86 that detects the amount of depression of the brake pedal 85, the vehicle speed V from the vehicle speed sensor 88, the road gradient θ from the gradient sensor 89, etc. Have been entered. In the embodiment, the gradient sensor 89 detects a positive value when climbing in the reverse direction and a negative value when climbing in the forward direction. 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.

  In the hybrid vehicle 20 of the embodiment, the position of the shift lever 81 detected by the shift position sensor 82 includes a parking position (P position), a neutral position (N position), a drive position (D position), and a reverse position (R Position). When the shift lever 81 is in the parking position, the brake or clutch (not shown) of the transmission 60 is normally released and the ring gear shaft 32a is disconnected from the drive shaft 36.

  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 backward is described. FIG. 2 is a flowchart showing an example of a reverse travel time drive control routine executed by the hybrid electronic control unit 70. This routine is repeatedly executed every predetermined time (for example, every several milliseconds) when the shift position SP is in the R position.

  When the reverse drive control routine is executed, the CPU 72 of the hybrid electronic control unit 70 firstly rotates the accelerator opening Acc from the accelerator pedal position sensor 84, the vehicle speed V from the vehicle speed sensor 88, and the motors MG1, MG2. A process of inputting data necessary for control, such as the number Nm1, Nm2, the remaining capacity SOC of the battery 50, the temporary output limit Wouttmp of the battery 50, the road surface gradient θ from the gradient sensor 89, is executed (step S100). Here, the rotational speeds Nm1 and Nm2 of the motors MG1 and MG2 are input from the motor ECU 40 by communication from those 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. To do. The remaining capacity SOC of the battery 50 is calculated based on the charge / discharge current Ib from the battery 50 and input from the battery ECU 52 by communication. Further, the temporary output limit Wouttmp of the battery 50 is set based on the battery temperature Tb of the battery 50 and the remaining capacity SOC of the battery 50 and is input from the battery ECU 52 by communication. In the embodiment, the temporary output limit Wouttmp of the battery 50 is set to the basic output limit Woutbase based on the battery temperature Tb, the output limit correction coefficient k1 is set based on the remaining capacity SOC of the battery 50, and the battery 50 The correction coefficient k2 is set based on the charging / discharging current Ib from and the basic output limit Woutbase set is multiplied by the correction coefficient k1 and the correction coefficient k2. 3 shows an example of the relationship between the battery temperature Tb and the basic output limit Woutbase, FIG. 4 shows an example of the relationship between the remaining capacity SOC of the battery 50 and the correction coefficient k1, and FIG. 5 shows the charge / discharge current from the battery 50. An example of the relationship between Ib and the correction coefficient k2 is shown. Here, the basic output limit Woutbase and the correction coefficients k1 and k2 are provisional output limits used for setting the output limit Wout for suppressing deterioration of the battery 50 based on the characteristics of the battery 50 configured as a lithium ion secondary battery. In order to set Wouttmp, a value determined by experimentation or the like can be used. In the embodiment, the correction coefficient k1 is set so as to decrease as the remaining capacity SOC of the battery 50 decreases, and the correction coefficient k2 is set to the battery 50. The charging / discharging current Ib is set so as to decrease as the charging / discharging current Ib increases toward the discharge side.

  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. 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 accelerator opening Acc, the vehicle speed V, and the like. , The corresponding required torque Tr * is derived and set from the stored map. FIG. 6 shows an example of a required torque setting map when traveling backward. From FIG. 6, a negative value is set for the required torque Tr *.

  Subsequently, the remaining capacity SOC of the battery 50 is compared with a threshold value Sref (step S120). Here, the threshold value Sref is a threshold value used for determining whether or not it is necessary to perform the load operation of the engine 22 and to generate power by the motor MG1, and for starting the motor 22 by motoring the motor MG1. The lower limit of the remaining capacity SOC required for the above or a value slightly larger than that can be used. FIG. 7 shows an example of a collinear diagram showing the dynamic relationship between the rotational speed and torque in the rotating elements of the power distribution and integration mechanism 30 when the engine 22 is traveling backward while being loaded. 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. The rotational speed Nr of the ring gear shaft 32a is obtained by multiplying the vehicle speed V by the conversion factor ka (Nr = ka · 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). The two thick arrows on the R axis indicate that the torque Tm1 output from the motor MG1 acts on the ring gear shaft 32a and the torque Tm2 output from the motor MG2 acts on the ring gear shaft 32a via the reduction gear 35. Torque. When the engine 22 is loaded and electric power is generated by the motor MG1, the driving force in the forward direction is output from the engine 22 to the ring gear shaft 32a as the drive shaft, as shown in the figure. Accordingly, a part of the driving force in the reverse direction output from the motor MG2 is canceled out by the driving force in the forward direction from the engine 22, so that the maximum driving force that can be output in the reverse direction stops the operation of the engine 22. Thus, it becomes smaller than when traveling only by the driving force from the motor MG2. For this reason, when traveling backward, it is desirable to travel using only the power from the motor MG2 as much as possible, and the remaining capacity SOC of the battery 50 and the threshold value Sref are compared in step S120.

  When the remaining capacity SOC of the battery 50 is equal to or greater than the threshold value Sref, it is determined that the engine 22 does not need to be loaded, and the correction coefficient α is set based on the road surface gradient θ (step S130), and the set correction coefficient α is set. The output limit Wout of the battery 50 is set by multiplying the temporary output limit Wouttmp of the battery 50 (step S140). Here, in the embodiment, the correction coefficient α is stored in the ROM 74 as a correction coefficient setting map by predetermining the relationship between the road surface gradient θ and the correction coefficient α, and from the stored map when the road surface gradient θ is given. The corresponding correction coefficient α is derived and set. An example of the correction coefficient setting map is shown in FIG. As shown in the figure, the correction coefficient α is set to a value of 1 when the road surface gradient θ is less than the threshold θref, and is set to tend to decrease from the value 1 as the road surface gradient θ increases in a region where the road surface gradient θ is equal to or greater than the threshold θref. It was supposed to be. Here, the threshold value θref is a lower limit of the road surface gradient θ that can be determined to be an uphill gradient in the reverse direction, and for example, 0 °, 2 °, 3 °, or the like is used. Further, in the embodiment, when the road surface gradient θ is relatively large, the correction coefficient k2 used for suppressing the deterioration of the battery 50 and the temporary output limit Wouttmp based on the correction coefficient k2 are not reduced beyond the assumed range. Therefore, the correction coefficient α is set in this way.

  Then, a value 0 is set for both the target rotational speed Ne * and the target torque Te * of the engine 22 (step S150), and a value 0 is set for the torque command Tm1 * of the motor MG1 (step S160). 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 (1) (step S170), 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 Tm2min as a lower limit (upper limit of absolute value of 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 expressed by the formula ( 2) (step S180), and the larger of the calculated provisional torque Tm2tmp and torque limit Tm2min (absolute value) The smaller) set as the torque command Tm2 * of the motor MG2 as the value (step S190). Here, Formula (1) can be easily derived from the alignment chart of FIG. In this case, since the value 0 is set in the torque command Tm1 *, the temporary torque Tm2tmp is a value obtained by dividing the required torque Tr * by the gear ratio Gr of the reduction gear 35, and the torque limit Tm2min is the output limit Wout. This is a value divided by the rotation speed Nm2 of the motor MG2.

Tm2tmp = (Tr * + Tm1 * / ρ) / Gr (1)
Tm2min = (Wout-Tm1 * ・ Nm1) / Nm2 (2)

  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. Torque commands Tm1 * and Tm2 * for motors MG1 and MG2 are transmitted to motor ECU 40 (step S200), and the reverse drive control control routine is terminated. The engine ECU 24 that has received the target rotational speed Ne * and the target torque Te * having the value 0 stops the operation of the engine 22. 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. With such control, the engine 22 can stop traveling and output torque based on the required torque Tr * to the ring gear shaft 32a as the drive shaft within the range of the output limit Wout of the battery 50.

  On the other hand, when the remaining capacity SOC of the battery 50 is less than the threshold value Sref, it is determined that the engine 22 needs to be loaded, and when the engine 22 is stopped (step S210), the engine 22 is driven by the motor MG1. Is started by motoring (step 220). Then, the temporary output limit Wouttmp of the battery 50 is set to the output limit Wout (step S230), and the required torque Tr * is multiplied by the rotational speed Nr (= Nm2 / Gr) of the ring gear shaft 32a as the drive shaft. The power Pe * is set (step S240), and the target rotational speed Ne * and the target torque Te * of the engine 22 are set as operating points at which the engine 22 can be efficiently operated using the set required power Pe * (step S240). Step S250).

  Subsequently, 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 (3). Formula (4) 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. Is used to calculate the torque command Tm1 * of the motor MG1 (step S260), the torque command Tm2 * of the motor MG2 is set (steps S170 to S190), and the target rotational speed Ne * and target torque Te * of the engine 22 are set. The torque commands Tm1 * and Tm2 * for the motors MG1 and MG2 are transmitted to the engine ECU 24 to the motor ECU 40 (step Step S200), the reverse drive control control routine is terminated. Expression (3) can be easily derived by using the alignment chart of FIG. Expression (4) is a relational expression in feedback control for rotating the motor MG1 at the target rotation speed Nm1 *. In Expression (4), “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. With such control, it is possible to travel by outputting torque based on the required torque Tr * to the ring gear shaft 32a within the range of the output limit Wout with the load operation of the engine 22. At this time, since torque in the forward direction is output from the engine 22 to the ring gear shaft 32a via the power distribution and integration mechanism 30, the upper limit of the torque that can be output in the reverse direction is higher than that when the engine 22 is stopped. And get smaller. In the embodiment, when traveling backward on an uphill road with the operation stop of the engine 22, the output limit Wout is set based on the road surface gradient θ so that the output limit Wout tends to be smaller than when the road is not uphill. The upper limit of the torque that can be output in the reverse direction at this time is set to a relatively large output limit Wout regardless of whether it is an uphill road (for example, output using a correction coefficient α having a value of 1 regardless of the road surface gradient θ). It is smaller than that for setting the limit Wout. Accordingly, when the vehicle travels backward on an uphill road, it is possible to suppress a large change in the torque output in the backward direction depending on whether the engine 22 is stopped or loaded, giving the driver an uncomfortable feeling. Can be suppressed.

Nm1 * = Ne * ・ (1 + ρ) / ρ-Nm2 / (Gr ・ ρ) (3)
Tm1 * =-ρ ・ Te * / (1 + ρ) + k1 (Nm1 * -Nm1) + k2∫ (Nm1 * -Nm1) dt (4)

  FIG. 9 is an explanatory diagram illustrating an example of a temporal change in the reverse direction torque Trev (= −Tr) output to the ring gear shaft 32a as a drive shaft when the vehicle travels backward on an uphill road with respect to the reverse direction. In FIG. 9, for reference, when a relatively large output limit Wout is set without considering the road gradient θ regardless of whether the engine 22 is in a load operation (when the engine 22 is not in a load operation). As a comparative example, the output limit Wout is set by multiplying the temporary output limit Wouttmp by the correction coefficient α of the value 1 to the temporary output limit Wouttmp. In the comparative example, as shown by a broken line, when the vehicle travels backward on an uphill road, the battery 50 has a remaining capacity SOC to some extent, and before the time t1 when the engine 22 does not need to be loaded, the first operation depends on the driver's operation. In this case, the vehicle can travel backward by outputting a relatively large reverse torque Trev to the ring gear shaft 32a. However, as the charge / discharge current Ib increases accordingly, the output limit Wout decreases, so the reverse direction. Torque Trev decreases rapidly. Then, when the remaining capacity SOC decreases and the engine 22 is motored by the motor MG1 and started (time t1 to t2), thereafter, the engine 22 is loaded and the reverse direction torque Trev is generated with the power generation by the motor MG1. Is output to the ring gear shaft 32a, and at this time, part of the backward torque output from the motor MG2 is canceled by the forward torque from the engine 22. On the other hand, in the embodiment, as shown by a solid line, when traveling backward on an uphill road, before time t3 when the remaining capacity SOC of the battery 50 is some and the engine 22 does not need to be loaded, based on the road gradient θ. Using the output limit Wout set to tend to be smaller than when the road is not uphill when traveling on the uphill road, the vehicle travels by outputting the reverse direction torque Trev to the ring gear shaft 32a, and the remaining capacity SOC is reduced. Is started (time t3 to t4), and thereafter, the engine 22 is driven under load, and a reverse torque Trev is output to the ring gear shaft 32a along with power generation by the motor MG1. In this way, when traveling backward on an uphill road, by reducing the output limit Wout when the engine 22 is not in a load operation based on the road surface gradient θ, the reverse travel when the engine 22 is stopped is performed. The upper limit of the direction torque Trev becomes smaller, and the fluctuation with respect to the time change of the reverse direction torque Trev, for example, the decrease of the upper limit of the reverse direction torque Trev with respect to the time when the engine 22 is not loaded and The degree of decrease in the torque Trev after the reverse direction torque Trev reaches its peak can be suppressed. Thereby, it is possible to suppress the driver from feeling uncomfortable when traveling backward on the uphill road. In addition, when the vehicle 22 travels backward on an uphill road without a load operation, the output limit Wout is made smaller than when it is not on an uphill road, and the motor MG2 is controlled within that range so that the torque Trev in the reverse direction is increased. By outputting to the ring gear shaft 32a, it is possible to suppress a decrease in the remaining capacity SOC and to delay the timing of starting the engine 22, and to reduce the output limit Wout of the battery 50 beyond the assumed range. Thus, a certain amount of torque Trev can be output to the ring gear shaft 32a for a longer time in a state where the operation of the engine 22 is stopped.

  According to the hybrid vehicle 20 of the above-described embodiment, when traveling backward on an uphill road in the reverse direction, when traveling backward with the operation of the engine 22 stopped, based on the remaining capacity SOC of the battery 50 and the road surface gradient θ. The output limit Wout of the battery 50 is set so as to be smaller than when the road is not uphill, the engine 22 is stopped, the torque command Tm1 * of the motor MG1 is set to 0, and the output limit of the battery 50 is further limited. The torque command Tm2 * of the motor MG2 is set so as to travel with the required torque Tr * within the range of Wout to control the engine 22 and the motors MG1 and MG2, and when traveling backward with a load operation of the engine 22, the battery 50 The output limit Wout of the battery 50 is set based on the remaining capacity SOC and the set output limit range is set. The engine 22 and the motors MG1 and MG2 are controlled by setting the target rotational speed Ne * and the target torque Te * of the engine 22 and the torque commands Tm1 * and Tm2 * of the motors MG1 and MG2 so that the engine 22 travels with the required torque Tr *. From the above, it is possible to prevent the torque Trev (= −Tr) in the reverse direction from greatly fluctuating between when the operation of the engine 22 is stopped and when the engine 22 is under load operation. It is possible to suppress the driver from feeling uncomfortable.

  In the hybrid vehicle 20 of the embodiment, the condition for the remaining capacity SOC of the battery 50 to be less than the threshold value Sref is used as a condition for the load operation of the engine 22, but in addition to this, the output limit Wout of the battery 50 and the like A condition where the temporary output limit Wouttmp is less than or equal to a predetermined value may be used.

  According to the hybrid vehicle 20 of the embodiment, as shown in FIG. 8, in the region where the road surface gradient θ is equal to or greater than the threshold value θref, the correction coefficient α is set so as to decrease as the road surface gradient θ increases. However, a constant (for example, 0.5 or 0.7) may be used as long as the correction coefficient α is set to be smaller than that in the region where the road surface gradient θ is less than the threshold value θref. It may be set such that the gradient θ decreases linearly as the gradient θ increases, or the gradient decreases stepwise with two or more steps as the road surface gradient θ increases.

  In the hybrid vehicle 20 of the embodiment, a lithium ion secondary battery is used as the battery 50. However, instead of this, a nickel hydrogen secondary battery or the like may be used. When using a nickel metal hydride secondary battery or the like, the temporary output of the battery 50 based on the remaining capacity SOC and the battery temperature Tb regardless of the charge / discharge current Ib from the battery 50 (by setting the correction coefficient k2 to 1). The limit Wouttmp may be set.

  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 changed by the reduction gear 35 and output to the ring gear shaft 32a. However, as illustrated in the hybrid vehicle 120 of the modification of FIG. May be connected to an axle (an axle connected to the wheels 64a and 64b in FIG. 10) 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.

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

Here, the correspondence between the main elements of the embodiment and the main elements of the invention described in the column of means for solving the problems will be described. In the embodiment, the 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 “ The battery ECU 52 that corresponds to the “storage means” and calculates the remaining capacity SOC that is the amount of power that can be discharged from the battery 50 based on the charge / discharge current Ib from the battery 50 corresponds to the “remaining capacity detection means”, and the road surface gradient θ Is a road surface gradient detecting means, which sets a temporary output limit Wouttmp based on the remaining capacity SOC of the battery 50, the battery temperature Tb of the battery 50, and the charge / discharge current Ib, and is used for hybrid electronics. When the vehicle ECU 52 travels backward with the operation stop of the battery ECU 52 and the engine 22 transmitted to the control unit 70, the road surface gradient θ is determined based on the road surface gradient θ. When the vehicle is traveling backward in FIG. 2, the correction coefficient α is set so as to be smaller than when the slope is not climbing in the direction, and the output limit Wout is set by multiplying the temporary output limit Wouttmp by the correction coefficient α. The electronic control unit for hybrid 70 executes the processing of steps S130 and S140 of the drive control routine, and executes the processing of step S230 for setting the temporary output limit Wout to the output limit Wout when traveling backward with the load operation of the engine 22. Corresponds to the “output limit setting means” and sets the required torque Tr * based on the accelerator opening Acc and V, and executes the process of step S110 of the reverse travel drive control routine of FIG. 70 corresponds to “required driving force setting means”, which is accompanied by stoppage of operation of the engine 22 or load operation. The target rotational speed Ne * and target torque Te * of the engine 22 and torque commands Tm1 * and Tm2 * of the motors MG1 and MG2 are set within the range of the output limit Wout and transmitted to the engine ECU 24 and the motor ECU 40 in FIG. The engine ECU 24 that controls the engine 22 based on the hybrid electronic control unit 70 that executes the processes of steps S150 to S200 and S240 to S260 of the reverse drive control routine and the received target rotational speed Ne * and target torque Te *. The motor ECU 40 that controls the motors MG1 and MG2 based on the received torque commands Tm1 * and Tm2 * corresponds 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 rotatable independently of the drive shaft and outputs at least part of the power from the output shaft to the drive shaft as power in the forward direction with input and output of electric power and power It doesn't matter what. 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 axle, such as an induction motor. The “power storage means” is not limited to the battery 50 as a lithium ion secondary battery, and may be capable of exchanging power with power power input / output means or an electric motor such as a secondary battery such as nickel metal hydride or a capacitor. It does not matter as long as it is anything. The “remaining capacity detection means” is not limited to the one that calculates the remaining capacity SOC of the battery 50 based on the charge / discharge current Ib from the battery 50, but the remaining capacity that is the amount of power that can be discharged from the power storage means. Any device can be used as long as it can detect. The “road surface gradient detecting means” is not limited to the gradient sensor 89, and any device that detects a road surface gradient may be used. The “output restriction setting means” is not limited to the combination of the hybrid electronic control unit 70 and the battery ECU 52, and may be configured by a single electronic control unit. Further, as the “output limitation”, the temporary output limitation Wouttmp is set based on the remaining capacity SOC of the battery 50, the battery temperature Tb of the battery 50, and the charge / discharge current Ib, and the vehicle travels backward with the operation of the engine 22 stopped. Sometimes, based on the road surface gradient θ, the correction coefficient α is set so that the road surface gradient θ is smaller when the vehicle is climbing in the reverse direction than when it is not the uphill gradient, and the temporary output limit Wouttmp is multiplied by the correction coefficient α. When the output limit Wout is set and the vehicle 22 travels backward with a load operation, the provisional output limit Wout is not limited to the output limit Wout, and is set without using the charge / discharge current Ib. For example, or set based on the internal resistance of the battery 50 in addition to the remaining capacity SOC and the battery temperature Tb. When the road surface gradient is an uphill gradient in the reverse direction based on the remaining capacity and the road surface gradient, the discharge from the power storage means is allowed to be smaller than when the road surface gradient is not the uphill gradient in the reverse direction As long as the output limit that is the maximum power to be set is set, it may be anything. 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 “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”, the target engine speed Ne *, the target torque Te *, the torque of the motors MG1, MG2 within the range of the output limit Wout depending on whether the operation of the engine 22 is stopped or accompanied by a load operation. It is not limited to setting the commands Tm1 * and Tm2 * to control the engine 22 and the motors MG1 and MG2, and one of the conditions is that the remaining capacity reaches a predetermined remaining capacity or less when traveling backward. As long as the internal combustion engine, the power power input / output means, and the electric motor are controlled so as to travel with the requested driving force within the range of the output restriction accompanying the load operation of the internal combustion engine due to the establishment of the load condition, any may be used. . 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 a mechanism using a double pinion planetary gear mechanism or a combination of a plurality of planetary gear mechanisms and four or more shafts. Connected to the three shafts, such as those connected to the shaft and those having a different operation action from the planetary gear such as a differential gear, and connected to the three shafts of the drive shaft, the output shaft, and the rotating shaft of the generator. 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. The correspondence between the main elements of the embodiment and the main elements of the invention described in the column of means for solving the problems is the same as that of the embodiment described in the column of means for solving the problems. It is an example for specifically explaining the best mode for doing so, and does not limit the elements of the invention described in the column of means for solving the problems. In other words, the interpretation of the invention described in the column of means for solving the problem 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 problem. 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 as an embodiment of the present invention. It is a flowchart which shows an example of the drive control routine at the time of reverse travel performed by the hybrid electronic control unit 70 of an Example. It is explanatory drawing which shows an example of the relationship between battery temperature Tb and basic output restrictions Woutbase. It is explanatory drawing which shows an example of the relationship between the remaining capacity SOC of the battery 50, and the correction coefficient k1. It is explanatory drawing which shows an example of the relationship between the charging / discharging electric current Ib from the battery 50, and the correction coefficient k2. It is explanatory drawing which shows an example of the map for request | requirement torque setting. 3 is an explanatory diagram showing an example of a collinear diagram showing a dynamic relationship between the number of rotations and torque in a rotating element of the power distribution and integration mechanism 30 when the engine 22 is traveling backward while being loaded. FIG. It is explanatory drawing which shows an example of the map for a correction coefficient setting. It is explanatory drawing which shows an example of the mode of a time change of the torque Trev (= -Tr) of the reverse direction output to the ring gear axis | shaft 32a as a drive shaft, when driving backward on the uphill road with respect to the reverse direction. 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, 51a voltage sensor, 51b current sensor, 51c temperature sensor, 52 electronic control unit for battery (Battery ECU), 54 power line, 60 gear mechanism, 62 differential gear, 63a, 63b driving wheel, 64a, 64b wheel, 70 hybrid electronic control unit, 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 Gradient sensor, 230 Counter rotor motor, 232 Inner rotor 234 Outer rotor, MG1, MG2 motor.

Claims (6)

Power from the output shaft connected to the internal combustion engine and a drive shaft connected to the axle and connected to the output shaft of the internal combustion engine so as to be able to rotate independently of the drive shaft and with input and output of electric power and power A power motive power input / output means for outputting at least a part of the power to the drive shaft as power in the forward direction, and an electric motor capable of outputting power to the axle,
A power storage means capable of exchanging power with the electric power drive input / output means and the electric motor;
A remaining capacity detecting means for detecting a remaining capacity, which is an amount of power that can be discharged from the power storage means;
Road surface gradient detecting means for detecting the road surface gradient;
When traveling backward, based on the detected remaining capacity and the detected road surface gradient, when the road surface gradient is an uphill gradient in the reverse direction and the road surface gradient is not an uphill gradient in the reverse direction Output limit setting means for setting an output limit that is the maximum power allowed to discharge from the power storage means in a tendency to be smaller than
A required driving force setting means for setting a required driving force required for traveling;
When the vehicle travels in reverse, the output limit is set within the set output limit with the load operation of the internal combustion engine due to the establishment of a load condition where one of the conditions is that the detected remaining capacity reaches a predetermined remaining capacity or less. Control means for controlling the internal combustion engine, the power drive input / output means, and the electric motor so as to travel with a set required driving force;
A vehicle comprising:   2. The vehicle according to claim 1, wherein the output restriction setting means is a means for setting the output restriction so that the detected road surface gradient tends to decrease as the climbing gradient in the reverse direction increases.   The output restriction setting means is a means for setting the output restriction on the basis of the detected remaining capacity regardless of the detected road surface gradient when the internal combustion engine is subjected to load operation due to the establishment of the load condition. The vehicle according to claim 1 or 2. A vehicle according to any one of claims 1 to 3,
The power storage means is a lithium ion secondary battery,
The output restriction setting means is means for setting the output restriction so that the output current tends to decrease as the discharge current from the power storage means increases.   The power motive power input / output means is connected to three axes of a generator for inputting / outputting motive power, the drive shaft, the output shaft, and a rotating shaft of the generator, and enters any two of the three axes. The vehicle according to any one of claims 1 to 4, wherein the vehicle includes three-axis power input / output means for inputting / outputting power to / from the remaining shaft based on the output power. Power from the output shaft connected to the internal combustion engine and a drive shaft connected to the axle and connected to the output shaft of the internal combustion engine so as to be able to rotate independently of the drive shaft and with input and output of electric power and power Power motive power input / output means that outputs at least a part of the power to the drive shaft as power in the forward direction, an electric motor that can output power to the axle, and an electric storage that can exchange electric power with the power motive power input / output means and the motor A vehicle control method comprising:
When traveling backward, based on the remaining capacity, which is the amount of power that can be discharged from the power storage means, and the road surface gradient, the road surface gradient is an uphill gradient in the reverse direction when the road surface gradient is an uphill gradient in the reverse direction. Is set to an output limit that is the maximum power that is allowed to be discharged from the power storage means, and the remaining capacity is one of the conditions that the remaining capacity falls below a predetermined remaining capacity. Controlling the internal combustion engine, the power power input / output means, and the electric motor so as to travel with the required driving force required for traveling within the set output limit range with the load operation of the internal combustion engine due to establishment.
A method for controlling a vehicle.

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