JP2015101239A - Vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve fuel economy in a temporary-retreating travel for a hybrid vehicle.SOLUTION: A vehicle 1 includes: an engine 100; motor-generators MG 1, MG 2; a power division mechanism 300 including a carrier CA, a sun gear S and a ring gear R, which are linked respectively to a crank shaft 110 of the engine 100, a rotor 410 of the motor-generator MG 1 and a rotary shaft 415 of the motor-generator MG 2; a propeller shaft 430; an automatic transmission 500 disposed between the motor-generator MG 2 and propeller shaft 430; a battery to which charging and discharging are applied in association with rotation of the motor-generator MG 1; and an ECU for controlling the automatic transmission 500. The ECU controls the automatic transmission 500 so that rotational directions of the motor-generator MG 1 are switched between a forward direction and a reverse direction in accordance with an SOC of the battery.

Description

  The present invention relates to a vehicle, and more particularly to a vehicle including first and second rotating electrical machines.

  There is known a hybrid vehicle in which an engine and first and second motor generators (rotary electric machines) are mounted as a drive system. In such a hybrid vehicle, when the drive system fails, evacuation travel control may be executed depending on the failure location. The retreat travel control is a control for temporarily continuing the travel rather than immediately stopping the vehicle. Thereby, the driver can evacuate the vehicle to a safe place or move the vehicle to a repair shop.

  Japanese Patent Laying-Open No. 2006-320068 (Patent Document 1) discloses a hybrid vehicle including a rotation direction switching unit for retreat travel. The rotation direction switching means is provided when the first motor generator is rotating forward and the battery charge amount is determined to be greater than a predetermined amount when the second motor generator fails. The rotation direction of the motor generator is switched from forward rotation to reverse rotation.

JP 2006-320068 A

  The hybrid vehicle including the drive system can travel straight when the second motor generator fails. The direct travel is travel performed only by direct torque (torque transmitted directly from the engine to the drive shaft via the power split mechanism) while the power is generated by the motor generator MG1 when the second motor generator fails.

  During straight running, the first motor generator outputs negative torque. Therefore, when the rotation speed of the first motor generator is positive, the battery is charged. If charging continues, the battery may reach an overcharged state. On the other hand, when the rotation speed of the first motor generator is negative, the battery is discharged. If discharging continues, the battery may reach an overdischarged state. When the battery reaches an overcharged state or an overdischarged state, the vehicle cannot travel. Therefore, it is necessary to control the rotation speed of the first motor generator so that the SOC (State Of Charge) of the battery is maintained within an appropriate range during straight traveling.

  The engine speed of a hybrid vehicle is generally determined so that the fuel efficiency is good. On the other hand, in order to protect the battery as described above, it is necessary to switch the rotation direction of the first motor generator. In the hybrid vehicle disclosed in Patent Document 1, the rotation direction of the first motor generator is switched by changing the engine rotation speed. However, when the engine is operated with good fuel efficiency, changing the engine speed for battery protection may deteriorate the fuel efficiency. As a result, the evacuation travel distance is shortened.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to improve fuel efficiency in retreat travel of a hybrid vehicle.

  A vehicle according to an aspect of the present invention includes a first to a first engine coupled to an internal combustion engine, first and second rotating electrical machines, an output shaft of the internal combustion engine, and rotating shafts of the first and second rotating electrical machines, respectively. Charging / discharging is executed according to the rotation of the first rotating electrical machine, the power split mechanism including three rotating elements, the drive shaft, the transmission provided between the second rotating electrical machine and the drive shaft, and the first rotating electrical machine. A power storage device and a control unit that controls the transmission are provided. The control unit controls the transmission such that the rotation direction of the first rotating electrical machine is switched between the forward direction and the reverse direction according to the SOC of the power storage device.

  According to the above configuration, when the second rotating electrical machine fails, the rotational speed of the first rotating electrical machine can be changed by controlling the transmission instead of the internal combustion engine. That is, it is not necessary to change the rotation speed of the internal combustion engine when switching the rotation direction of the first rotating electrical machine. Therefore, the internal combustion engine can be kept in a good fuel economy state.

  Preferably, when the SOC is higher than the first value, the control unit determines the rotation direction of the first rotating electric machine so that the electric storage device is discharged. When the SOC is lower than a second value smaller than the first value, the control unit determines the rotation direction of the first rotating electrical machine so that the power storage device is charged.

  According to the above configuration, the SOC of the power storage device can be maintained between the first value and the second value. Therefore, the power storage device can be prevented from reaching an overcharge state or an overdischarge state.

  Preferably, the control unit controls the internal combustion engine so that the rotation speed of the internal combustion engine becomes constant when the second rotating electrical machine fails.

  According to the above configuration, the rotational speed of the internal combustion engine can be kept constant at a rotational speed at which fuel efficiency is good.

  Preferably, the transmission is a stepped transmission having a plurality of shift stages. The control unit is configured to charge or discharge power of the power storage device that is assumed when each of the two or more shift stages among the plurality of shift stages is switched to the corresponding shift stage when the second rotating electrical machine fails. Is calculated, and the shift stage to be switched is determined based on the calculated charging power or discharging power.

  According to the above configuration, in a vehicle equipped with a stepped transmission, the control accuracy of the SOC of the power storage device can be improved by calculating a predicted value of charging power or discharging power prior to switching of the shift speed. .

  Preferably, the control unit selects a shift stage in which the absolute value of the rotation speed of the first rotating electrical machine is less than the upper limit value and the torque of the first rotating electrical machine is greater than or equal to the lower limit value among the plurality of shift stages. To control the transmission.

  According to the above configuration, the first rotating electrical machine can be prevented from over-rotating. In addition, with respect to the torque of the first rotating electrical machine, it is possible to ensure the minimum torque necessary for the retreat travel.

  Preferably, a temperature detection unit that detects the temperature of the power storage device is further provided. The control unit controls the transmission so that the absolute value of the rotation speed of the first rotating electrical machine decreases when the temperature is higher than the upper limit value when the second rotating electrical machine fails.

  When the charging speed or discharging speed of the power storage device is large, the temperature of the power storage device increases. When the power storage device reaches a high temperature, the vehicle cannot travel. According to the above configuration, when the temperature of the power storage device is higher than the upper limit value, the absolute value of the rotation speed of the first rotating electrical machine is decreased. As a result, the charging speed or discharging speed of the power storage device is reduced. Therefore, further temperature increase of the power storage device can be suppressed.

  According to the present invention, the fuel efficiency can be improved in the retreat travel of the hybrid vehicle.

1 is a block diagram schematically showing a configuration of an entire vehicle according to an embodiment. It is a figure which shows the structure of the automatic transmission shown in FIG. 1 in detail. It is a figure which shows the engagement action | operation table | surface of the automatic transmission shown in FIG. FIG. 3 is a shift diagram used for shift control of the automatic transmission shown in FIG. 2. FIG. 5 is a collinear diagram of a power split mechanism for explaining shift control used for discharging a battery when a motor generator MG2 fails. FIG. 5 is a collinear diagram of a power split mechanism for explaining shift control used for charging a battery when a motor generator MG2 fails. It is a flowchart which shows control of the automatic transmission by ECU.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals, and description thereof will not be repeated.

  FIG. 1 is a block diagram schematically showing the overall configuration of the vehicle according to the embodiment. Referring to FIG. 1, vehicle 1 includes an engine (E / G) 100, motor generators MG1 and MG2, a power split mechanism 300, an automatic transmission (A / T) 500, an inverter (INV) 610, 620, a battery (BAT) 700, and an electronic control unit (ECU) 1000.

  Engine 100 generates power for rotating drive wheels 80 based on control signal CSE from ECU 1000. The power generated by engine 100 is output to power split device 300.

  Power split device 300 divides the power received from engine 100 into power transmitted to drive wheels 80 and power transmitted to motor generator MG1. Power split device 300 is a planetary gear mechanism and includes a sun gear S, a ring gear R, a carrier CA, and a pinion gear P.

  Sun gear S is coupled to rotor 410 (rotating shaft) of motor generator MG1. Ring gear R is coupled to rotation shaft 415 of motor generator MG2. The pinion gear P meshes with the sun gear S and the ring gear R. The carrier CA holds the pinion gear P so as to rotate and revolve freely. Carrier CA is coupled to crankshaft 110 (output shaft) of engine 100. The carrier CA, the sun gear S, and the ring gear R correspond to “first to third rotating elements”, respectively.

  Each of motor generators MG1 and MG2 (first and second rotating electric machines) is an AC rotating electric machine, and can function as both a motor and a generator. However, motor generator MG1 mainly functions as a generator. On the other hand, motor generator MG2 mainly functions as a motor.

  In this embodiment, automatic transmission 500 is a stepped transmission having a plurality of shift speeds. Automatic transmission 500 is provided between motor generator MG2 and propeller shaft 430. More specifically, the motor is connected to the drive shaft 420 that connects the ring gear R of the power split mechanism 300 and the rotation shaft of the gear of the input shaft of the automatic transmission 500 (hereinafter referred to as the input shaft 440) (see FIG. 2). The rotor of generator MG2 is connected. The automatic transmission 500 may be a continuously variable transmission.

  FIG. 2 is a diagram showing in detail the configuration of automatic transmission 500 shown in FIG. Although FIG. 1 schematically shows an automatic transmission 500, a connection relationship between an input shaft and an output shaft of the automatic transmission 500 will be described in detail with reference to FIG.

  Referring to FIG. 2, automatic transmission 500 includes single pinion type planetary gears 510 and 520, clutches C1 and C2, brakes B1 and B2, and a one-way clutch F1. Planetary gear 510 has sun gear S1, ring gear R1, carrier CA1, and pinion gear P1. Planetary gear 520 has sun gear S2, ring gear R2, carrier CA2, and pinion gear P2.

  Each of the clutches C1 and C2 and the brakes B1 and B2 is a friction engagement device that is operated by hydraulic pressure. When the clutch C1 is engaged, the sun gear S2 is connected to the ring gear R of the power split mechanism 300. Accordingly, the sun gear S2 rotates at the same speed as the ring gear R.

  The carrier CA1 of the planetary gear 510 and the ring gear R2 of the planetary gear 520 are connected to each other. Therefore, when clutch C2 is engaged, both carrier CA1 and ring gear R2 are coupled to ring gear R of power split mechanism 300. Thereby, the carrier CA1 and the ring gear R2 rotate at the same speed as the ring gear R.

  When the brake B1 is engaged, the rotation of the sun gear S1 is stopped. When the brake B2 is engaged, the rotation of the carrier CA1 and the ring gear R2 is stopped. The one-way clutch F1 supports the carrier CA1 and the ring gear R2 so as to be rotatable in one direction and not rotatable in the other direction.

  The automatic transmission 500 is switched to an engaged state, a slip state, or a released state by changing the engagement state of each friction engagement device (clutch C1, C2 and brake B1, B2). It is done. In the engaged state, the entire torque of the input shaft 440 of the automatic transmission 500 is transmitted to the output shaft 450 of the automatic transmission 500. In the slip state, part of the torque of the input shaft 440 of the automatic transmission 500 is transmitted to the output shaft 450. In the released state, torque transmission between the input shaft 440 and the output shaft 450 of the automatic transmission 500 is interrupted.

  The automatic transmission 500 can switch the gear ratio (ratio of the rotational speed of the input shaft 440 to the rotational speed of the output shaft 450) based on the control signal CSA from the ECU 1000.

  FIG. 3 is a diagram showing an engagement operation table of the automatic transmission 500 shown in FIG. Referring to FIG. 3, “◯” indicates an engaged state, “(◯)” indicates that the engine is engaged during engine braking, and a blank indicates a released state.

  In the automatic transmission 500, each friction engagement device is engaged in accordance with the engagement operation table, whereby four forward gears (first gear to fourth gear (indicated by 1st to 4th)), A reverse gear (indicated by R) is alternatively formed. Further, a neutral state (indicated by N) is formed by setting all the friction engagement devices to the released state. The configuration of the automatic transmission shown in FIG. 2 and the engagement operation table shown in FIG. 3 are merely examples, and are not limited to these.

  Referring to FIG. 1 again, battery 700 (power storage device) stores DC power for driving motor generators MG1, MG2. As the battery 700, for example, a nickel metal hydride battery, a lithium ion battery, or a capacitor can be employed.

  Inverters 610 and 620 are connected in parallel to battery 700. Inverters 610 and 620 convert DC power from battery 700 into AC power based on control signals PWI1 and PWI2 from ECU 1000, respectively. The AC power converted by inverters 610 and 620 is supplied to motor generators MG1 and MG2, respectively.

  The vehicle 1 further includes resolvers 91 and 92, an engine rotation speed sensor 93, a vehicle speed sensor 94, a monitoring sensor 95, and overcurrent sensors 96 and 97. Resolver 91 detects the rotational speed (MG1 rotational speed Ng) of motor generator MG1. Resolver 92 detects the rotational speed (MG2 rotational speed Nm) of motor generator MG2. Engine speed sensor 93 detects the speed of engine 100 (engine speed Ne). The vehicle speed sensor 94 detects the rotation speed of the propeller shaft 430 (propeller shaft rotation speed Np). Monitoring sensor 95 detects the state of battery 700 (battery voltage Vb, battery current Ib, battery temperature Tb). Overcurrent sensor 96 detects an overcurrent (current I1) of motor generator MG1. Overcurrent sensor 97 detects an overcurrent (current I2) of motor generator MG2. Each sensor outputs a detection result to ECU 1000. The monitoring sensor 95 corresponds to a “temperature detector”.

  ECU 1000 includes a CPU (Central Processing Unit) and a memory (both not shown). For example, a shift diagram (see FIG. 4) described later is stored in the memory. ECU 1000 executes predetermined arithmetic processing based on information stored in the memory and information from each sensor. ECU 1000 controls each device based on the result of the arithmetic processing.

  FIG. 4 is a shift diagram used for shift control of automatic transmission 500 shown in FIG. Referring to FIG. 4, the horizontal axis represents the vehicle speed, and the vertical axis represents the accelerator opening.

  As described above, the automatic transmission 500 is configured to be able to form any one of the first gear to the fourth gear. In the shift diagram, an upshift line (shown by a solid line) and a downshift line (shown by a broken line) are set for each type of shift (combination of a gear stage before the shift and a gear stage after the shift).

  ECU 1000 controls automatic transmission 500 to upshift when the vehicle speed increases until the vehicle speed exceeds the vehicle speed defined by the upshift line. On the other hand, ECU 1000 controls automatic transmission 500 so as to shift down when the vehicle speed decreases until it becomes lower than the vehicle speed defined by the downshift line.

  Further, ECU 1000 controls automatic transmission 500 to upshift when the accelerator opening decreases until it becomes smaller than the accelerator opening defined by the upshift line. On the other hand, ECU 1000 controls automatic transmission 500 to shift down when the accelerator opening increases until the accelerator opening reaches or exceeds the accelerator opening defined by the downshift line.

  Motor generator MG2 may fail. ECU 1000 can determine that motor generator MG2 has failed when the detection results from resolver 92, monitoring sensor 95, or overcurrent sensor 97 indicate an abnormal value. The failure of motor generator MG2 includes the failure of each sensor itself for detecting the state of motor generator MG2.

  FIG. 5 is a collinear diagram of power split mechanism 300 for explaining the shift control used for discharging battery 700 when motor generator MG2 fails. 5, power split mechanism 300 is configured as described above, so that the rotational speed of sun gear S (MG1 rotational speed Ng), the rotational speed of carrier CA (engine rotational speed Ne), and ring gear R The rotational speed (MG2 rotational speed Nm) has a relationship of being connected by a straight line on the alignment chart. That is, if the rotation speed of any two of the rotation elements is determined, the rotation speeds of the remaining rotation elements are also determined.

  FIG. 5 shows the relationship between the rotational speeds of the rotating elements when the automatic transmission 500 forms the second gear to the fourth gear at a certain time. A straight line corresponding to the second speed gear stage is indicated by a dotted line, a straight line corresponding to the third speed gear stage is indicated by a solid line, and a straight line corresponding to the fourth speed gear stage is indicated by a one-dot chain line.

  In the present embodiment, the direct coupling stage is a third speed gear stage. That is, the gear ratio of the third gear (the ratio of the input shaft rotation speed to the output shaft rotation speed) is 1. Therefore, in the third gear, the MG2 rotational speed Nm is equal to the propeller shaft rotational speed Np. In the second gear, the MG2 rotational speed Nm is larger than the propeller shaft rotational speed Np. In the fourth gear, the MG2 rotational speed Nm is smaller than the propeller shaft rotational speed Np. Therefore, ECU 1000 can change MG2 rotational speed Ng by controlling automatic transmission 500 to switch the gear stage when motor generator MG2 fails.

  The engine rotation speed Ne is fixed at a constant speed (indicated by black circles in FIG. 5). In other words, ECU 1000 controls engine 100 such that engine rotation speed Ne is constant. On the other hand, the propeller shaft rotation speed Np can be increased or decreased according to the vehicle speed at each time (indicated by the up and down arrows in FIG. 5). The MG1 rotational speed Ng is determined according to the propeller shaft rotational speed Np and the selected gear stage at each time.

  The MG1 rotational speed Ng is determined so that the rotational speeds of the respective rotating elements are aligned on the alignment chart when the engine rotational speed Ne and the MG2 rotational speed Nm are determined. Depending on whether the MG1 rotational speed Ng is positive or negative (that is, the rotational direction of the motor generator MG1), charging and discharging of the battery 700 are switched.

  In the example shown in FIG. 5, the MG1 rotational speed Ng in the fourth gear is positive. When MG1 rotation speed Ng is positive (when the rotation direction of motor generator MG1 is the forward direction), motor generator MG1 generates power. Therefore, when the fourth gear is selected, battery 700 is charged. If the charging of the battery 700 continues for a long time, the battery 700 may reach an overcharged state. Therefore, it is necessary to discharge the battery 700 so that the battery 700 does not reach an overcharged state.

  On the other hand, the MG1 rotational speed Ng in the second gear and the third gear is both negative. When MG1 rotation speed Ng is negative (when the rotation direction of motor generator MG1 is the reverse direction), motor generator MG1 consumes the electric power stored in battery 700. Therefore, ECU 1000 can discharge battery 700 by controlling automatic transmission 500 to downshift from the fourth gear to the second gear or the third gear.

  The discharge speed (discharge amount per unit time) from battery 700 increases as the absolute value of MG1 rotation speed Ng increases. In the example shown in FIG. 5, the absolute value of the MG1 rotational speed Ng at the second gear is larger than the absolute value of the MG1 rotational speed Ng at the third gear. Therefore, the discharge speed in the second gear is larger than the discharge speed in the third gear. Therefore, when battery 700 needs to be discharged rapidly, ECU 1000 controls automatic transmission 500 to downshift from the fourth gear to the second gear.

  It is also conceivable to downshift from the fourth gear to the first gear (not shown). However, it is preferable that ECU 1000 selects the downshift destination gear to prevent motor generator MG1 from over-rotating. When the first gear is selected, the absolute value of the usable rotational speed of the MG1 rotational speed Ng may exceed the upper limit value Ngmax. ECU 1000 preferably controls automatic transmission 500 so as to select the downshift destination gear stage at which the absolute value of MG1 rotation speed Ng is less than upper limit value Ngmax.

  ECU 1000 preferably controls automatic transmission 500 so as to select the downshift destination gear stage at which torque Tg generated by motor generator MG1 is equal to or greater than the lower limit value Tmin of the torque required for traveling of vehicle 1. .

  Thus, when it is necessary to discharge battery 700 rapidly, ECU 1000 does not over-rotate motor generator MG1, and among the gear stages where torque Tg generated by motor generator MG1 is equal to or greater than lower limit value Tmin. The automatic transmission 500 is controlled so as to select a gear stage that maximizes the discharge speed.

  On the other hand, when the necessity for rapidly discharging battery 700 is not so high as described above, ECU 1000 controls automatic transmission 500 to downshift from the fourth gear to the third gear. That is, when it is not necessary to rapidly discharge battery 700, ECU 1000 controls automatic transmission 500 so as to select a gear stage having a gear ratio lower than the gear stage having the maximum discharge speed. In this speed change control as well, ECU 1000 preferably selects a gear stage at which motor generator MG1 does not over-rotate and torque Tg generated by motor generator MG1 is not less than lower limit value Tmin.

  As described above, when the battery 700 needs to be discharged, the ECU 1000 determines that the downtime is based on the alignment chart (more specifically, the engine rotation speed Ne and the propeller shaft rotation speed Np on the alignment chart) at that time. The automatic transmission 500 is controlled to shift. Thereby, the battery 700 can be discharged. Further, the discharge rate can be adjusted by selecting the downshift destination gear.

  FIG. 6 is a collinear diagram of power split mechanism 300 for describing the shift control used for charging battery 700 when motor generator MG2 fails. FIG. 6 is contrasted with FIG.

  In the example shown in FIG. 6, the MG1 rotational speed Ng in the second gear is negative. Therefore, when the second gear is selected, battery 700 is discharged. If the discharge of the battery 700 continues for a long period of time, the battery 700 may reach an overdischarge state. Therefore, it is necessary to charge the battery 700 so that the battery 700 does not reach an overdischarged state.

  On the other hand, the MG1 rotational speed Ng in the third gear and the fourth gear is both positive. Therefore, ECU 1000 can charge battery 700 by controlling automatic transmission 500 to upshift from the second gear to the third gear or the fourth gear.

  When it is necessary to charge battery 700 rapidly, ECU 1000 controls automatic transmission 500 so as to select a gear stage that maximizes the charging speed (charge amount per unit time). In the present embodiment, when battery 700 needs to be discharged rapidly, ECU 1000 controls automatic transmission 500 to upshift from the second gear to the fourth gear.

  On the other hand, when the need for rapidly charging battery 700 is not as high as described above, ECU 1000 controls automatic transmission 500 so as to select a gear stage having a higher gear ratio than the gear stage having the maximum charging speed. To do. In the present embodiment, when it is not necessary to rapidly charge battery 700, ECU 1000 controls automatic transmission 500 so as to upshift from the second gear to the third gear.

  Thus, when charging of battery 700 is necessary, ECU 1000 is based on the nomograph at that time (more specifically, engine rotation speed Ne and propeller shaft rotation speed Np on the nomograph). The automatic transmission 500 is controlled to upshift. Thereby, the battery 700 can be charged. In addition, the charging speed can be adjusted by selecting the gear position of the upshift destination.

  In the selection of the upshift destination gear stage, it is preferable that motor generator MG1 does not over-rotate and torque Tg generated by motor generator MG1 is equal to or greater than lower limit value Tmin. It is the same as in the case of selection. Therefore, detailed description will not be repeated here.

  As described above with reference to FIGS. 5 and 6, ECU 1000 controls automatic transmission 500 such that rotation direction of motor generator MG <b> 1 switches between the forward direction and the reverse direction in accordance with the SOC of battery 700. .

  Here, as disclosed in Patent Document 1, it is conceivable to change the rotation direction of the motor generator MG1 by changing the engine rotation speed Ne. However, when the engine is already running with good fuel consumption (for example, when the operating point indicating the engine rotation speed is on the optimum fuel consumption line), changing the engine rotation speed may deteriorate the fuel consumption. As a result, the evacuation travel distance may be shortened.

  According to the present embodiment, the engine rotation speed Ne is maintained constant. In this case, the engine rotation speed Ne is preferably a low speed (for example, 1000 rpm (rotation per minute or less)). Furthermore, it is more preferable that the operating point indicating the engine speed Ne is on the optimum fuel consumption line. Thereby, fuel consumption can be improved.

  Further, when the engine speed Ne is changed, the noise and vibration (NV: Noise Vibration) of the engine 100 changes. Such a change in NV is not caused by an operation intended by the user (for example, an accelerator operation), and thus may give the user a feeling of strangeness. According to the present embodiment, since the engine rotation speed Ne is maintained constant, NV does not change. Therefore, it is possible to prevent the user from feeling uncomfortable.

  FIG. 7 is a flowchart showing control of the automatic transmission 500 by the ECU 1000. Referring to FIG. 7, the process shown in this flowchart is executed, for example, every predetermined period or every time a predetermined condition is satisfied.

  In this flowchart, the SOC of the battery 700 is divided into five ranges (less than 30%, 30% to 40%, 40% to 70%, 70% to 80%, 80% or more). A different process is executed for each SOC range. However, specific numerical values of the SOC can be appropriately changed in accordance with the characteristics of the battery 700 and the like. Also, the SOC classification is not limited to five. 70% corresponds to the “first value”, and 40% corresponds to the “second value”.

  Further, when the environmental temperature of battery 700 is high or when battery current Ib is large, battery temperature Tb rises. When the battery temperature Tb becomes high, the vehicle 1 cannot travel. Therefore, in addition to the SOC of battery 700, a process based on battery temperature Tb is executed.

  In step S10, ECU 1000 determines whether or not motor generator MG2 has failed. If motor generator MG2 has failed (YES in step S10), the process proceeds to step S20. On the other hand, when motor generator MG2 has not failed (NO in step S10), the process proceeds to step S120.

  In step S20, ECU 1000 determines whether or not the SOC of battery 700 is 70% or more. If the SOC is 70% or more (YES in step S20), the process proceeds to step S30. On the other hand, when the SOC is less than 70% (NO in step S20), the process proceeds to step S70.

  In step S30, when motor generator MG2 fails, ECU 1000 determines that the gear for each of two or more gear stages (second gear stage and third gear stage in the example shown in FIG. 5). The charging power or discharging power of the battery 700 that is assumed when switching to the gear is calculated, and the upshift destination or the downshift destination gear is determined based on the calculated charging power or discharge power. More specifically, the predicted value of the discharge power is represented by the product of the torque command value of motor generator MG1 and MG1 rotation speed Ng plus a loss that will occur during discharge. The MG1 rotation speed Ng can be obtained from the nomograph based on the engine rotation speed Ne and the MG2 rotation speed Nm. ECU 1000 can store in advance a map indicating the relationship between the torque command value of motor generator MG1, the MG1 rotation speed Ng, and the loss that would occur in that case, for example. Thus, by calculating the predicted value of the discharge power prior to the gear stage switching, the control accuracy of the SOC of the battery 700 can be improved. Thereafter, the process proceeds to step S40.

  In step S40, ECU 1000 determines whether or not the SOC is 80% or higher and battery temperature Tb is lower than or equal to predetermined upper limit value Tc. If SOC is 80% or higher and battery temperature Tb is lower than upper limit value Tc (YES in step S40), the process proceeds to step S50. On the other hand, when SOC is less than 80% (that is, SOC is 70% or more and less than 80%) or battery temperature Tb is higher than upper limit value Tc (NO in step S40), the process proceeds to step S60.

  In step S50, ECU 1000 controls automatic transmission 500 to downshift two steps. Thereafter, the process returns to the main routine, and the series of processes shown in FIG. 7 is repeated.

  In step S60, ECU 1000 controls automatic transmission 500 so as to shift down by one step. As shown in steps S50 and S60, ECU 1000 determines the rotation direction of motor generator MG1 so that battery 700 is discharged when the SOC is higher than 70%. Thereafter, the process returns to the main routine, and the series of processes shown in FIG. 7 is repeated.

  In step S70, ECU 1000 determines whether or not the SOC of battery 700 is less than 40%. If the SOC is less than 40% (YES in step S70), the process proceeds to step S80. On the other hand, when the SOC is 40% or more, that is, when the SOC is 40% or more and less than 70% (NO in step S70), the process proceeds to step S120.

  In step S80, when motor generator MG2 fails, ECU 1000 determines battery 700 for each of two or more gear stages (in the example shown in FIG. 6, third gear stage and fourth gear stage) among the plurality of gear stages. The predicted value of the charging power is calculated. Since the method for calculating the predicted value of charging power is the same as the method for calculating the predicted value of discharging power (see step 30), description thereof will not be repeated. Thereafter, the process proceeds to step S90.

  In step S90, ECU 1000 determines whether or not SOC is less than 30% and battery temperature Tb is equal to or lower than upper limit value Tc. If SOC is less than 30% and battery temperature Tb is equal to or lower than upper limit value Tc (YES in step S90), the process proceeds to step S100. On the other hand, when SOC is 30% or more (that is, SOC is 30% or more and less than 40%) or battery temperature Tb is higher than upper limit value Tc (NO in step S90), the process proceeds to step S110.

  In step S100, ECU 1000 controls automatic transmission 500 to upshift two steps. Thereafter, the process returns to the main routine, and the series of processes shown in FIG. 7 is repeated.

  In step S110, ECU 1000 controls automatic transmission 500 to shift up by one step. As shown in steps S100 and S110, ECU 1000 determines the rotation direction of motor generator MG1 so that battery 700 is charged when the SOC is lower than 40%. Thereafter, the process returns to the main routine, and the series of processes shown in FIG. 7 is repeated.

  In step S120, ECU 1000 controls automatic transmission 500 so as to execute A / T sequential shift control. A / T sequential shift control is shift control during normal operation of motor generator MG2. That is, during the A / T sequential shift control, a shift change based on the vehicle speed and the accelerator opening is performed according to the shift diagram shown in FIG.

  The reason why the A / T sequential shift control is performed will be described. It is preferable that a certain degree of direct torque is obtained even at a low vehicle speed, even in the case of retreat travel. Moreover, it is preferable that a certain high vehicle speed can be obtained. Therefore, when the SOC of the battery 700 is within an appropriate range (40% to 70% in the example shown in FIG. 7), the gear ratio is not simply selected based on the SOC, but the gear ratio is low at low vehicle speeds. While using a high gear stage, a gear stage having a low gear ratio is used at high vehicle speeds.

  Finally, referring to FIG. 1 again, the present embodiment will be summarized. Vehicle 1 includes engine 100, motor generators MG1 and MG2, crankshaft 110 of engine 100, rotor 410 of motor generator MG1, and carrier CA, sun gear S, and ring gear R coupled to rotation shaft 415 of motor generator MG2. Power split mechanism 300, propeller shaft 430, automatic transmission 500 provided between motor generator MG2 and propeller shaft 430, and battery 700 that is charged and discharged according to the rotation of motor generator MG1. And an ECU 1000 that controls the automatic transmission 500. ECU 1000 controls automatic transmission 500 according to the SOC of battery 700 so that the rotation direction of motor generator MG1 is switched between the forward direction and the reverse direction.

  Preferably, ECU 1000 determines the rotation direction of motor generator MG1 so that battery 700 is discharged when SOC is higher than 70% (first value). When the SOC is lower than 40% (second value), which is smaller than 70%, ECU 1000 determines the rotation direction of motor generator MG1 so that charging is performed from battery 700.

  Preferably, ECU 1000 controls engine 100 such that engine rotation speed Ne is constant when motor generator MG2 fails.

  Preferably, automatic transmission 500 is a stepped transmission having a plurality of gear stages. ECU 1000 calculates, for each of two or more gear stages of the plurality of gear stages, the charging power or discharging power of battery 700 that is assumed when switching to the gear stage when motor generator MG2 fails. Based on the calculated charging power or discharging power, an upshift destination or downshift destination gear is determined.

  Preferably, ECU 1000 automatically selects a gear stage in which the absolute value of MG1 rotational speed Ng is less than upper limit value Ngmax and torque Tg of motor generator MG1 is equal to or greater than lower limit value Tmin among a plurality of gear stages. The transmission 500 is controlled.

  Preferably, a monitoring sensor 95 for detecting the battery temperature Tb is further provided. ECU 1000 controls automatic transmission 500 such that the absolute value of MG1 rotation speed Ng decreases when battery temperature Tb is higher than upper limit value Tc when motor generator MG2 fails.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  1 vehicle, 80 drive wheels, 91,92 resolver, 93 engine rotation speed sensor, 94 vehicle speed sensor, 95 monitoring sensor, 96,97 overcurrent sensor, 100 engine, 300 power split mechanism, 110 crankshaft, 410 rotor, 415 rotation Shaft, 420 drive shaft, 430 propeller shaft, 440 input shaft, 450 output shaft, 500 automatic transmission, 510,520 planetary gear, 610,620 inverter, 700 battery, 1000 ECU, MG1, MG2 motor generator, C1, C2 clutch, B1, B2 brake, F1 one-way clutch, S, S1, S2 sun gear, R, R1, R2 ring gear, CA, CA1, CA2 carrier, P, P1, P2 pinion gear.

Claims (6)

An internal combustion engine;
First and second rotating electrical machines;
A power split mechanism including first to third rotating elements respectively connected to an output shaft of the internal combustion engine and rotating shafts of the first and second rotating electrical machines;
A drive shaft;
A transmission provided between the second rotating electric machine and the drive shaft;
A power storage device that is charged and discharged according to the rotation of the first rotating electrical machine;
A control unit for controlling the transmission,
When the second rotating electrical machine fails, the control unit shifts the shift so that the rotation direction of the first rotating electrical machine is switched between the forward direction and the reverse direction according to the SOC of the power storage device. A vehicle that controls the machine.   When the SOC is higher than a first value, the control unit determines the rotation direction of the first rotating electric machine so that the electric storage device is discharged, and the SOC is the first value. 2. The vehicle according to claim 1, wherein the rotation direction of the first rotating electrical machine is determined so that the power storage device is charged when the value is lower than a second value smaller than the value.   The vehicle according to claim 1, wherein the control unit controls the internal combustion engine so that a rotation speed of the internal combustion engine is constant when the second rotating electrical machine fails. The transmission is a stepped transmission having a plurality of shift stages,
The control unit is configured to charge the power storage device that is assumed when each of the two or more shift stages among the plurality of shift stages is switched to the shift stage when the second rotating electrical machine fails. The vehicle according to any one of claims 1 to 3, wherein power or discharge power is calculated, and a shift destination gear stage is determined based on the calculated charge power or discharge power.   The control unit is a shift stage in which the absolute value of the rotational speed of the first rotating electrical machine is less than an upper limit value and the torque of the first rotating electrical machine is greater than or equal to a lower limit value among the plurality of shift stages. The vehicle according to claim 4, wherein the transmission is controlled to select A temperature detection unit for detecting the temperature of the power storage device;
The control unit controls the transmission so that the absolute value of the rotational speed of the first rotating electrical machine decreases when the temperature is higher than an upper limit when the second rotating electrical machine fails. The vehicle according to any one of claims 1 to 3.

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