JP6146292B2 - Hybrid car - Google Patents

Description

  The present invention relates to a hybrid vehicle. More specifically, the present invention relates to an engine, a first motor, a driving shaft coupled to an axle, an output shaft of the engine, and a planetary gear having three rotating elements connected to a rotating shaft of the first motor. A second motor having a rotating shaft connected to the drive shaft, a first inverter for driving the first motor, a second inverter for driving the second motor, and the first inverter and the second inverter. And a battery that exchanges electric power with the first motor and the second motor.

  Conventionally, in this type of hybrid vehicle, an engine, a first motor generator, a drive shaft coupled to an axle, an output shaft of the engine, and a rotation shaft of the first motor are connected to a ring gear, a carrier, and a sun gear. It has a power split mechanism, a second motor generator with a rotor connected to the drive shaft, and a battery that exchanges power with the first motor generator and the second motor generator. It has been proposed that the motoring of the engine by the first motor generator is started immediately before the front wheel comes into contact with the step after detecting this (for example, see Patent Document 1). In this hybrid vehicle, the driving force for riding over the steps is increased by such control.

JP 2013-103593 A

  In such a hybrid vehicle, when the second motor generator is in a motor locked state (energized but not rotating), current concentrates on a specific phase of the second motor generator and the second motor generator Since the temperature rise of the generator or the like is easily promoted, lock protection control for limiting the torque of the second motor generator may be executed in order to suppress overheating of the second motor generator. Therefore, after that, one of the issues is how to overcome the step.

  The main purpose of the hybrid vehicle of the present invention is to make it possible to more reliably get over a step in reverse travel.

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

The hybrid vehicle of the present invention
An engine, a first motor, a drive shaft connected to an axle, a planetary gear in which three rotation elements are connected to an output shaft of the engine and a rotation shaft of the first motor, and a rotation shaft connected to the drive shaft Torque of the second motor when the concentrated current flows in a specific phase of the second motor, a battery that exchanges power with the first motor and the second motor, and a specific phase of the second motor. A hybrid vehicle comprising: control means for performing lock protection control for limiting
The control means performs power running control on the first motor while the lock protection control is being released when the shift position is the reverse travel position, the accelerator opening is greater than or equal to a predetermined opening, and the vehicle speed is less than the predetermined vehicle speed. Means,
It is characterized by that.

  In the hybrid vehicle of the present invention, when the current concentrates on the specific phase of the second motor and the lock protection control is executed to limit the torque of the second motor, the shift position is the reverse travel. When the accelerator opening is greater than or equal to the predetermined opening and the vehicle speed is less than the predetermined vehicle speed at the position, the first motor is subjected to power running control while the lock protection control is released (the torque in the direction that increases the engine speed is increased). Output from one motor). Here, the “lock protection control” is started when it is determined that the current concentrates and flows in a specific phase of the second motor (the second motor is in a motor lock state). It is released when it is determined that the concentrated current flowing in the phase has been released. The “lock protection control” is control for gradually decreasing the absolute value of the torque of the second motor. Furthermore, “when the shift position is the reverse travel position, the accelerator opening is greater than or equal to a predetermined opening, and the vehicle speed is less than the predetermined vehicle speed” may be considered, for example, when trying to get over a step in reverse travel. When the first motor is subjected to power running control during reverse travel, torque resulting from engine friction and inertia (assist torque for reverse travel) can be applied to the drive shaft in addition to the torque from the second motor. In the hybrid vehicle of the present invention, the reverse running torque can be increased by performing the power running control of the first motor while the lock protection control is released. As a result, when there is a step in the reverse direction, the step can be more reliably overcome.

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 motor MG1 control routine at the time of reverse travel performed by HVECU70 of an Example. It is explanatory drawing which shows an example of the collinear diagram which shows the dynamic relationship of the rotation speed and torque in the rotation element of the planetary gear 30 at the time of raising the rotation speed Ne of the engine 22 with the motor MG1. An example of how the motor MG2 torque Tm2, the rotational speed Ne of the engine 22, the inertia Tei and friction Tef of the engine 22 and the torque Tr output to the drive shaft 36 change over time when attempting to get over the step in reverse travel. It is explanatory drawing shown.

  Next, the form for implementing this invention is demonstrated using an Example.

  FIG. 1 is a configuration diagram showing an outline of the configuration of a hybrid vehicle 20 as an embodiment of the present invention. As shown in the drawing, the hybrid vehicle 20 of the embodiment includes an engine 22 that outputs power using gasoline or light oil as a fuel, an engine electronic control unit (hereinafter referred to as an engine ECU) 24 that controls the drive of the engine 22, an engine, and the like. A planetary gear 30 having a carrier connected to the crankshaft 26 and a ring gear connected to a drive shaft 36 connected to drive wheels 38a and 38b via a differential gear 37, and a rotor configured as a synchronous generator motor, for example. Motor MG1 connected to the sun gear of planetary gear 30, for example, a motor MG2 configured as a synchronous generator motor and having a rotor connected to drive shaft 36, inverters 41 and 42 for driving motors MG1 and MG2, Inverters 41 and 42 not shown A motor electronic control unit (hereinafter referred to as a motor ECU) 40 that drives and controls the motors MG1 and MG2 by switching the elements, and a motor MG1, configured as, for example, a lithium ion secondary battery via inverters 41 and 42. A battery 50 that exchanges power with the MG 2, a battery electronic control unit (hereinafter referred to as a battery ECU) 52 that manages the battery 50, and a hybrid electronic control unit (hereinafter referred to as a HVECU) 70 that controls the entire vehicle. Prepare.

  The engine ECU 24 receives signals from various sensors necessary for controlling the operation of the engine 22 via an input port, and the engine ECU 24 outputs various control signals for controlling the operation of the engine 22. It is output through the port. The engine ECU 24 calculates the rotational speed Ne of the engine 22 based on a signal from a crank position sensor (not shown) attached to the crankshaft 26 of the engine 22.

  Signals from various sensors necessary to drive and control the motors MG1 and MG2 are input to the motor ECU 40 via an input port. The motor ECU 40 switches the inverters 41 and 42 to switching elements (not shown). A control signal or the like is output via the output port. The motor ECU 40 determines the rotational speeds Nm1, Nm2 of the motors MG1, MG2 based on the rotational positions θm1, θm2 of the rotors of the motors MG1, MG2 from the rotational position detection sensor that detects the rotational positions of the rotors of the motors MG1, MG2. Arithmetic.

  Signals from various sensors necessary for managing the battery 50 are input to the battery ECU 52 via the input port. The battery ECU 52 manages the battery 50 based on the integrated value of the charge / discharge current Ib of the battery 50 detected by a current sensor (not shown), and the ratio of the capacity of power that can be discharged from the battery 50 at that time to the total capacity And calculating input / output limits Win and Wout which are allowable input / output powers that may charge / discharge the battery 50 based on the calculated storage ratio SOC and the battery temperature Tb. Yes.

  The HVECU 70 includes an ignition signal from the ignition switch 80, a shift position SP from the shift position sensor 82 that detects the operation position of the shift lever 81, and an accelerator opening from the accelerator opening sensor 84 that detects the amount of depression of the accelerator pedal 83. Acc, the brake pedal position BP from the brake pedal position sensor 86 that detects the depression amount of the brake pedal 85, the vehicle speed V from the vehicle speed sensor 88, and the like are input via the input port. The HVECU 70 is communicably connected to the engine ECU 24, the motor ECU 40, and the battery ECU 52, and exchanges various control signals and data with the engine ECU 24, the motor ECU 40, and the battery ECU 52. In the hybrid vehicle 20 of the embodiment, the operation position of the shift lever 81 (shift position SP detected by the shift position sensor 82) includes a parking position (P position) used during parking, and a reverse position (R for reverse travel). Position), neutral position (N position), forward drive position (D position), etc.

  In the hybrid vehicle 20 of the embodiment configured in this way, during forward travel, the hybrid travel mode (HV travel mode) that travels with the operation of the engine 22 and the operation (fuel injection control, etc.) of the engine 22 are stopped. The vehicle travels in the electric travel mode (EV travel mode) and basically travels in the EV travel mode during reverse travel.

  When traveling in the HV traveling mode, the HVECU 70 sets a required torque Tr * (a positive value when traveling forward) required for traveling based on the accelerator opening Acc and the vehicle speed V. Subsequently, the set required torque Tr * is multiplied by the rotational speed Nr of the drive shaft 36 (for example, the rotational speed Nm2 of the motor MG2 (a positive value when traveling forward)) to obtain the traveling power Pdrv * required for traveling. The required power required for the vehicle is calculated by subtracting the calculated charge / discharge required power Pb * of the battery 50 based on the storage ratio SOC of the battery 50 (a positive value when discharging from the battery 50) from the calculated traveling power Pdrv *. Set Pe *. Then, the target rotational speed Ne * and the target torque Te * of the engine 22 are set using the required power Pe * and an operation line for efficiently operating the engine 22 (for example, an optimum fuel efficiency operation line). The torque command Tm1 * of the motor MG1 is set by the rotation speed feedback control so that the rotation speed Ne becomes the target rotation speed Ne *. Then, when the motor MG1 is driven with the torque command Tm1 *, the torque output from the motor MG1 and transmitted to the drive shaft 36 via the planetary gear 30 is subtracted from the required torque Tr * to calculate the temporary torque Tm2tmp of the motor MG2. The power consumption (generated power) of the motor MG1 obtained by multiplying the torque command Tm1 * of the motor MG1 by the rotational speed Nm1 is subtracted from the input / output limits Win and Wout of the battery 50 and further divided by the rotational speed Nm2 of the motor MG2. Torque limits Tm2min and Tm2max of the motor MG2 are calculated, and the temporary torque Tm2tmp is limited by the torque limits Tm2min and Tm2max and the positive and negative rated torques Tm2rat1 and Tm2rat2 to calculate the torque command Tm2 * of the motor MG2. Here, the rated torques Tm2rat1 and Tm2rat2 are set by applying the rotational speed Nm2 to a predetermined map for the relationship between the rotational speed Nm2 of the motor MG2 and the rated torques Tm2rat1 and Tm2rat2. Then, the target rotational speed Ne * and the target torque Te * are transmitted to the engine ECU 24, and the torque commands Tm1 * and Tm2 * are transmitted to the motor ECU 40. The engine ECU 24 that has received the target rotational speed Ne * and the target torque Te *, controls the intake air amount, fuel injection control, and ignition of the engine 22 so that the engine 22 is operated by the target rotational speed Ne * and the target torque Te *. Control and so on. The motor ECU 40 that has received the torque commands Tm1 * and Tm2 * performs switching control of the plurality of switching elements of the inverters 41 and 42 so that the motors MG1 and MG2 are driven by the torque commands Tm1 * and Tm2 *.

  During travel in the EV travel mode, the HVECU 70 sets the required torque Tr * based on the accelerator opening Acc and the vehicle speed V, sets a value 0 to the torque command Tm1 * of the motor MG1, and travels in the HV mode. The torque command Tm2 * for the motor MG2 is set and transmitted to the motor ECU 40 in the same manner as described above. Then, the motor ECU 40 that receives the torque commands Tm1 * and Tm2 * performs switching control of the switching elements of the inverters 41 and 42 so that the motors MG1 and MG2 are driven by the torque commands Tm1 * and Tm2 *.

  Further, in the hybrid vehicle 20 of the embodiment, when it is determined that the current concentrates and flows in the specific phase of the motor MG2 (the second motor is in the motor lock state), the current flows in the specific phase of the motor MG2. The lock protection control is executed in which the absolute value of the torque command Tm2 * of the motor MG2 is lowered to a predetermined value T1 slightly larger than the value 0 and held until it is determined that the concentrated flow is released. This lock protection control suppresses overheating of the motor MG2 in consideration of the fact that when a current flows in a specific phase of the motor MG2, the temperature rise of the motor MG2 is likely to be promoted due to heat generation in the specific phase. Done for. The start condition of the lock protection control is, for example, that any one of the currents Iu, Iv, and Iw flowing through each phase of the motor MG2 is equal to or greater than a predetermined value over a predetermined time (for example, several hundred msec or 1 second). Conditions can be used. The lock protection control release condition is, for example, a condition in which the motor MG2 rotates during execution of the lock protection control, and a current that is greater than or equal to a predetermined value among the currents Iu, Iv, and Iw is less than a predetermined value. Can be used. For example, when considering going over a step in reverse travel, the lock protection control is started when the motor MG2 enters the motor lock state when the rear wheel tire is slightly recessed due to the step. When the vehicle moves slightly forward due to the elastic force (repulsive force) of the rear wheel tire as the absolute value of the torque of the motor MG2 decreases, the lock protection control is released.

  Next, the operation of the hybrid vehicle 20 of the embodiment thus configured, particularly the operation when overcoming a step in reverse travel in the EV travel mode will be described. FIG. 2 is a flowchart illustrating an example of a reverse travel time motor MG1 control routine executed by the HVECU 70 of the embodiment. This routine is repeatedly executed during reverse travel. In parallel with this routine, the motor MG2 is controlled by the drive control described above.

  When the reverse running motor MG1 control routine is executed, the HVECU 70 firstly has the accelerator opening Acc from the accelerator opening sensor 84, the vehicle speed V from the vehicle speed sensor 88, the torque Tm of the motor MG2, the rotational speed Ne of the engine 22. Such data is input (step S100). Here, as the torque Tm2 of the motor MG2, torque estimated based on the phase current of each phase of the motor MG2 is input from the motor ECU 40 by communication. The torque command Tm2 * of the motor MG2 may be used. Further, as the rotational speed Ne of the engine 22, a value calculated based on a signal from a crank position sensor attached to the crankshaft 26 is input from the engine ECU 24 by communication.

  When the data is thus input, the input accelerator opening Acc is compared with the threshold value Aref (step S110), and the vehicle speed V is compared with the threshold value Vref (step S120). Here, the threshold value Aref and the threshold value Vref are whether or not the vehicle speed V is very low but the driver is stepping on the accelerator pedal 83, specifically, whether or not the driver is going over a step in reverse travel. The threshold value Aref can be 80% or 90%, for example, and the threshold value Vref can be 1 km / h or 2 km / h, for example.

  When the accelerator opening Acc is less than the threshold value Aref or when the vehicle speed V is higher than the threshold value Vref, it is determined that it is not in a situation where the vehicle is going over a step in reverse travel, and this routine is immediately terminated. In this case, the above-described drive control (drive control using a torque command Tm1 * of 0) is executed for the motor MG1.

  When the accelerator opening Acc is equal to or greater than the threshold value Aref and the vehicle speed V is equal to or less than the threshold value Vref, it is determined that the vehicle is going over a step in reverse travel, and it is determined whether lock protection control for the motor MG2 is being executed. (Step S130) When the lock protection control is being executed, the rotational speed Ne of the engine 22 is compared with a threshold value Neref (Step S180). Here, as the threshold value Neref, for example, 0 rpm, 500 rpm, 1000 rpm, or the like can be used. The significance of this threshold value Neref will be described later.

  When the rotational speed Ne of the engine 22 is higher than the threshold value Neref, a lowering command is transmitted to the motor ECU 40 so as to lower the rotational speed Ne of the engine 22 at the maximum lowering rate (step S190), and this routine ends. The motor ECU 40 that has received the lowering command drives (regenerates) the motor MG1 using a torque command Tm1 * for lowering the rotational speed Ne of the engine 22 at the maximum lowering rate. On the other hand, when the rotational speed Ne of the engine 22 is equal to or less than the threshold value Neref, this routine is finished as it is.

  When the lock protection control of the motor MG2 is not being executed, it is determined whether or not the torque Tm2 of the motor MG2 is equal to the negative rated torque Tm2rat2 (step S140), and when the torque Tm2 of the motor MG2 is equal to the rated torque Tm2rat2. It is determined whether or not the rotational speed Ne of the engine 22 is a maximum rotational speed Nemax (eg, 3000 rpm, 3500 rpm, etc.) (step S150).

  When the rotational speed Ne of the engine 22 is not the maximum rotational speed Nemax (less than the maximum rotational speed Nemax), a pull-up command is transmitted to the motor ECU 40 so as to increase the rotational speed Ne of the engine 22 at the maximum increase rate (step S160). ), This routine is terminated. On the other hand, when the rotational speed Ne of the engine 22 is the maximum rotational speed Nemax, a holding command is transmitted to the motor ECU 40 so as to maintain the rotational speed Ne of the engine 22 at the maximum rotational speed Nemax (step S170), and this routine is terminated. To do. When the motor ECU 40 receives the pull-up command, the motor ECU 40 drives and controls the motor MG1 (powering drive) using the torque command Tm1 * for pulling up the rotational speed Ne of the engine 22 at the maximum increase rate, and receives the holding command. Sometimes, the motor MG1 is driven and controlled using a torque command Tm1 * for maintaining the rotational speed Ne of the engine 22 at the maximum rotational speed Nemax.

  FIG. 3 is an explanatory diagram showing an example of a collinear diagram showing a dynamic relationship between the rotational speed and torque of the rotating element of the planetary gear 30 when the rotational speed Ne of the engine 22 is increased by the motor MG1. In the figure, the left S-axis indicates the rotational speed of the sun gear, which is the rotational speed Nm1 of the motor MG1, the C-axis indicates the rotational speed of the carrier, which is the rotational speed Ne of the engine 22, and the R-axis indicates the rotational speed Nm2 of the motor MG2. The rotation speed Nr of the ring gear is shown. Further, two thick arrows on the R axis indicate torque output from the motor MG1 and acting on the drive shaft 36 via the planetary gear 30, and torque output from the motor MG2 and acting on the drive shaft 36. When the rotation speed Ne of the engine 22 is held at the maximum rotation speed Nemax, torque caused by the friction Tef of the engine 22 (hereinafter referred to as holding-caused torque) can be applied to the drive shaft 36. Further, when the rotational speed Ne of the engine 22 is increased by the motor MG1, torque based on the inertia Tei and the friction Tef of the engine 22 (hereinafter referred to as “lifting-induced torque”) can be applied to the drive shaft 36. In the embodiment, since the rotational speed Ne of the engine 22 is increased at the maximum increase rate, the increase-induced torque can be further increased. Although the torque of the motor MG2 and the torque caused by holding or the torque caused by pulling can be output to the drive shaft 36, in the embodiment, when the torque Tm2 of the motor MG2 is equal to the rated torque Tm2rat2, the motor MG1 Since the rotational speed Ne is increased at the maximum increase rate, the torque output to the drive shaft 36 (the sum of the torque of the motor MG2 and the increase-induced torque) can be further increased. Thereby, when there is a step in the reverse direction, it is possible to more reliably get over the step. At this time, the rotational speed Ne of the engine 22 is set to the threshold value Neref or less during the lock protection of the motor MG2 as described above so that the rotational speed Ne of the engine 22 can be increased by the motor MG1. I will leave it. For this reason, it is preferable to use the value 0 as the threshold value Neref.

  FIG. 4 shows the change over time in the torque Tm of the motor MG2, the rotational speed Ne of the engine 22, the inertia Tei and the friction Tef of the engine 22, and the torque Tr output to the drive shaft 36 when trying to get over the step in reverse travel. It is explanatory drawing which shows an example of a mode. In the figure, the solid line indicates the state of the embodiment, and the alternate long and short dash line indicates the engine 22 regardless of whether the lock protection control of the motor MG2 is being executed or whether the torque Tm2 of the motor MG2 is equal to the rated torque Tm2rat2. The mode of the comparative example which starts raising of the rotation speed Ne is shown. For simplicity of explanation, the torque Tm2 of the motor MG2 is the same in the example and the comparative example. When the accelerator pedal 83 is depressed at time t1, the torque Tm2 of the motor MG2 starts to increase from the value 0 to the negative side (reverse travel side). If it is determined that the current concentrates and flows in a specific phase of the motor MG2 at t2 (the second motor is in the motor lock state), the lock protection control is started and the absolute value of the torque Tm2 gradually decreases. . When it is determined that the absolute value decreases and the vehicle slightly moves forward due to the repulsive force of the tires of the rear wheels and current is concentrated in the specific phase of the motor MG2 at time t3, the lock is stopped. After the protection is finished, the absolute value of the torque Tm2 gradually increases again, and reaches the negative rated torque Tm2rat2 at time t4. In the comparative example, since the rotational speed Ne of the engine 22 is raised by the motor MG1 from time t1, the lifting-induced torque cannot be effectively used after time t4, that is, the absolute value of the torque output to the drive shaft 36. The maximum value is not large enough. On the other hand, in the embodiment, since the lock protection control is not performed and the torque Tm2 of the motor MG2 becomes equal to the rated torque Tm2rat2, the rotational speed Ne of the engine 22 is increased at the maximum increase rate by the motor MG1. After t4, the pulling-induced torque can be effectively used, that is, a large torque can be output to the drive shaft 36 (the maximum absolute value of the torque output to the drive shaft 36 can be increased). As a result, the step in the reverse direction can be more reliably overcome.

  According to the hybrid vehicle 20 of the embodiment described above, the lock protection control is executed to gradually decrease the absolute value of the torque command Tm2 * of the motor MG2 when current is concentrated in a specific phase of the motor MG2. Therefore, when the lock protection control is not executed and the torque Tm2 of the motor MG2 is equal to the rated torque Tm2rat2, the rotational speed Ne of the engine 22 is increased by the motor MG1, so that the reverse traveling output to the drive shaft 36 is performed. The maximum value of torque can be increased. As a result, when there is a step in the reverse direction, the step can be more reliably overcome.

  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 the “engine”, the motor MG1 corresponds to the “first motor”, the planetary gear 30 corresponds to the “planetary gear”, the motor MG2 corresponds to the “second motor”, and the battery 50 Corresponds to the “battery”, and the HVECU 70, the engine ECU 24, and the motor ECU 40 correspond to the “control unit”.

  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 problem is the same as that of the embodiment described in the column of means for solving the problem. Therefore, the elements of the invention described in the column of means for solving the problems are not limited. That is, the interpretation of the invention described in the column of means for solving the problems should be made based on the description of the column, and the examples are those of the invention described in the column of means for solving the problems. It is only a specific example.

  As mentioned above, although the form for implementing this invention was demonstrated using the Example, this invention is not limited at all to such an Example, In the range which does not deviate from the summary of this invention, it is with various forms. Of course, it can be implemented.

  The present invention can be used in the manufacturing industry of hybrid vehicles.

  20 hybrid vehicle, 22 engine, 24 engine electronic control unit (engine ECU), 26 crankshaft, 30 planetary gear, 36 drive shaft, 37 differential gear, 38a, 38b drive wheel, 40 motor electronic control unit (motor ECU), 41, 42 Inverter, 50 battery, 52 Battery electronic control unit (battery ECU), 70 Hybrid electronic control unit (HVECU), 80 Ignition switch, 81 Shift lever, 82 Shift position sensor, 83 Accelerator pedal, 84 Accelerator opening Sensor, 85 brake pedal, 86 brake pedal position sensor, 88 vehicle speed sensor, MG1, MG2 motor.

Claims (1)

An engine, a first motor, a drive shaft connected to an axle, a planetary gear in which three rotation elements are connected to an output shaft of the engine and a rotation shaft of the first motor, and a rotation shaft connected to the drive shaft Torque of the second motor when the concentrated current flows in a specific phase of the second motor, a battery that exchanges power with the first motor and the second motor, and a specific phase of the second motor. A hybrid vehicle comprising: control means for performing lock protection control for limiting
When the shift position is the reverse travel position, the accelerator opening is greater than or equal to a predetermined opening and the vehicle speed is less than the predetermined vehicle speed, the torque of the second motor is rated while the lock protection control is released. Means for controlling the powering of the first motor when equal to the torque ;
A hybrid vehicle characterized by that.

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