JP2006044536A - Hybrid vehicle and control method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress a slip of a hybrid vehicle capable of traveling with the power from an engine and the power from a motor when a slip due to idling of a driving wheel and to outputs the driving force that a driver requires without requiring discharge using excessive electric power of a battery. <P>SOLUTION: When a slip is caused owing to idling of one driving wheel during a motor-driven travel, the torque from the motor is limited with a torque upper-limit value Tslip set based upon the rotational angular acceleration α of the rotary shaft of the motor to suppress the slip, the engine 22 is started (S350 to S370), and after it is confirmed that the start of the engine 22 is completed, braking force is applied to the driving wheel causing the slip to switch to slip suppressing control for suppressing the slip (S400). Consequently, the driving force that the driver requests can be outputted without requiring discharge using excessive electric power of the battery 50. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

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

Conventionally, as this type of hybrid vehicle, one that restricts the torque output to the drive shaft when slipping due to idling occurs in any of the drive wheels has been proposed (for example, see Patent Document 1). In this hybrid vehicle, slip due to idling is converged by reducing the torque upper limit value that may be output to the drive shaft as the angular acceleration of the drive wheels increases.
JP 2001-295676 A

  For hybrid vehicles that can be driven by power from the engine and power from the motor, the engine is stopped from the battery when relatively large power is not needed, such as when starting or running at low speed, for the purpose of improving energy efficiency. It uses only the power from the motor to drive. When slipping due to idling occurs in one of the drive wheels while the motor is running, the motor torque is limited to suppress the slip, but only by reducing the torque acting on the drive wheel causing the slip In addition, since the torque acting on the drive wheels that are not slipped is also reduced, the drive force required for the vehicle may not be output. In addition to limiting the motor torque, a slip suppression method is also conceivable that applies braking force to the slipped drive wheel. In this case, when the engine is started in response to a further drive force request, a drive force request is required. As a result of starting the engine while outputting the motor torque as a motor torque, when the motor torque is output and the engine is started using electric power from the battery, an excessive current may flow from the battery.

  A hybrid vehicle and a control method thereof according to the present invention provide a hybrid vehicle capable of traveling by power from an engine and power from a motor, and suppresses slipping when slippage occurs due to idling of driving wheels, and a power storage device such as a battery The purpose is to output the driving force requested by the driver without passing an excessive current.

  The hybrid vehicle and the control method thereof according to the present invention employ the following means in order to achieve at least a part of the above-described object.

The hybrid vehicle of the present invention
An internal combustion engine capable of outputting power to a drive shaft connected to an axle;
An electric motor capable of outputting power to the drive shaft;
Power storage means capable of exchanging electric power with the motor;
Slip determination means for determining that slippage due to idling has occurred in any of the left and right drive wheels connected to the axle;
Braking force application means for individually applying a braking force to the left and right drive wheels;
When the slip determination means determines that one of the left and right drive wheels has slipped while the internal combustion engine is not operating, the power output to the drive shaft is limited to suppress the slip. The internal combustion engine is controlled such that the electric motor is controlled and the internal combustion engine is started, and after the internal combustion engine is started, the braking force is applied to the drive wheel in which the slip is determined in order to suppress the slip. Control means for controlling the braking force application means so as to be acted on and controlling the internal combustion engine and the electric motor so that power is output to the drive shaft;
It is a summary to provide.

  In the hybrid vehicle of the present invention, when it is determined that a slip has occurred in any of the left and right drive wheels connected to the axle while the internal combustion engine is stopped, the hybrid vehicle is connected to the axle to suppress the slip. The motor is controlled so that the power output to the drive shaft is limited, and the internal combustion engine is controlled so that the internal combustion engine is started. After the internal combustion engine is started, slip is determined to suppress the slip. The internal combustion engine and the electric motor are controlled so as to control the braking force applying means for individually applying the braking force to the left and right driving wheels so that the braking force is applied to the driving wheels. That is, when a slip occurs in any of the left and right drive wheels while the internal combustion engine is stopped, first, the slip is suppressed by controlling the electric motor so that the power output to the drive shaft is limited. The internal combustion engine is started during the control for suppressing the slip by the electric motor. Therefore, it is possible to prevent the storage means from being discharged due to an excessive current that may be generated when the internal combustion engine is started while a large torque is being output from the electric motor. In addition, after the internal combustion engine is started, the braking force is applied to the drive wheel where the slip is generated from the braking force application means to suppress the slip and output from the internal combustion engine and the electric motor to the drive shaft. Can be output to the drive shaft.

  In such a hybrid vehicle of the present invention, required power setting means for setting required power to be output to the drive shaft based on a driver's operation, and start and stop of the internal combustion engine based on the set required power Start / stop determination means for determining whether or not slip has not been determined for any of the left and right drive wheels by the slip determination means, and the determination result by the start / stop determination means is executed. And controlling the internal combustion engine and the electric motor so that power based on the set required power is output to the drive shaft, and the left and right drive by the slip determination means in a state where the operation of the internal combustion engine is stopped. When slipping is determined for any of the wheels, the driving power that restricts the set required power to suppress the slip is the drive. Control the electric motor to be output to the engine and control the internal combustion engine so that the internal combustion engine is started regardless of the determination result by the start / stop determination means, and the slip determination in a state in which the internal combustion engine is operating. When a slip is determined for any of the left and right drive wheels by the means, the braking force application means is controlled so that a braking force is applied to the drive wheel for which the slip is determined in order to suppress the slip. It may be a means for controlling the internal combustion engine and the electric motor so that power based on the set required power is output to the drive shaft. In this way, power based on the required power can be output to the drive shaft, and the energy efficiency of the vehicle can be improved.

  In the hybrid vehicle of the present invention, at least part of the power from the internal combustion engine can be output to the drive shaft connected to the output shaft of the internal combustion engine and the drive shaft with input and output of electric power and power. Power motive power input / output means may be provided, and the power storage means may be means capable of exchanging power with the power power input / output means. In this case, the electric power drive input / output means is connected to the three shafts of the output shaft of the internal combustion engine, the drive shaft, and the rotary shaft, and is based on the power input / output to any two of the three shafts. It may be a means provided with a three-shaft power input / output means for inputting / outputting power to the remaining shaft and a generator capable of inputting / outputting power to / from the rotary shaft, or an output of the internal combustion engine A first rotor connected to the shaft and a second rotor connected to the drive shaft, and the first rotor and the second rotor rotate by relative rotation. It can also be a counter-rotor motor.

The hybrid vehicle control method of the present invention includes:
An internal combustion engine that can output power to a drive shaft connected to an axle, an electric motor that can output power to the drive shaft, an electric storage means that can exchange electric power with the motor, and left and right drive wheels are individually controlled. A braking force control means for applying power, and a hybrid vehicle control method comprising:
When slippage due to idling occurs in any of the left and right drive wheels connected to the axle while the internal combustion engine is stopped, the power output to the drive shaft is limited to suppress the slip. The internal combustion engine is controlled such that the electric motor is controlled and the internal combustion engine is started, and after the internal combustion engine is started, the slipping wheel is controlled to the drive wheel in which the slip is determined to suppress the slip. The gist is to control the braking force application means so that power is applied, and to control the internal combustion engine and the electric motor so that power is output to the drive shaft.

  In this hybrid vehicle control method of the present invention, when it is determined that a slip has occurred in any of the left and right drive wheels connected to the axle while the internal combustion engine is stopped, the slip is suppressed. The motor is controlled so that the power output to the drive shaft connected to the axle is limited, and the internal combustion engine is controlled so that the internal combustion engine is started. After the internal combustion engine is started, the slip is controlled to suppress the slip. The internal combustion engine and the electric motor are controlled so that power is output to the drive shaft as well as controlling the braking force application means for individually applying the braking force to the left and right drive wheels so that the braking force is applied to the drive wheel determined to be To do. That is, when a slip occurs in any of the left and right drive wheels while the internal combustion engine is stopped, first, the slip is suppressed by controlling the electric motor so that the power output to the drive shaft is limited. The internal combustion engine is started during the control for suppressing the slip by the electric motor. Therefore, it is possible to prevent the storage means from being discharged due to an excessive current that may be generated when the internal combustion engine is started while a large torque is being output from the electric motor. In addition, after the internal combustion engine is started, the braking force is applied to the drive wheel where the slip is generated from the braking force application means to suppress the slip and output from the internal combustion engine and the electric motor to the drive shaft. Can be output to the drive shaft.

  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, and an engine electronic control unit (hereinafter referred to as an engine ECU) that receives signals from various sensors that detect the operating state of the engine 22. ) 24 is under operation control such as fuel injection control, ignition control, intake air amount adjustment control. The engine ECU 24 is in communication with the hybrid electronic control unit 70, controls the operation of the engine 22 by a control signal from the hybrid electronic control unit 70, and, if necessary, transmits data related to the operating state of the engine 22 to the hybrid electronic control. Output to unit 70.

  The power distribution and integration mechanism 30 includes an external gear sun gear 31, an internal gear ring gear 32 disposed 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. 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 battery 50 is managed by a battery electronic control unit (hereinafter referred to as a battery ECU) 52. The battery ECU 52 receives signals necessary for managing the battery 50, for example, a voltage between terminals from a voltage sensor (not shown) installed between terminals of the battery 50, and a power line 54 connected to the output terminal of the battery 50. The charging / discharging current from the attached current sensor (not shown), the battery temperature Tb from the temperature sensor 51 attached to the battery 50, and the like are input. Output to the control unit 70. The battery ECU 52 also calculates the remaining capacity (SOC) based on the integrated value of the charge / discharge current detected by the current sensor in order to manage the battery 50.

  The hybrid electronic control unit 70 is configured as a microprocessor centered on the CPU 72, and in addition to the CPU 72, a ROM 74 for storing processing programs, a RAM 76 for temporarily storing data, an input / output port and communication not shown. And a port. The hybrid electronic control unit 70 includes an ignition signal from an ignition switch 80, a shift position SP from a shift position sensor 82 that detects the operation position of the shift lever 81, and an accelerator pedal position sensor 84 that detects the amount of depression of the accelerator pedal 83. The accelerator pedal opening Acc from the vehicle, the brake pedal position BP from the brake pedal position sensor 86 for detecting the depression amount of the brake pedal 85, the vehicle speed V from the vehicle speed sensor 88, and the wheel speed attached to the rotating shafts of the drive wheels 63a and 63b. Wheel speeds Vl, Vr, etc. from the sensors 64a, 64b are inputted via the input port. The hybrid electronic control unit 70 outputs drive signals to hydraulic brakes 66a and 66b attached to the drive wheels 63a and 63b. As described above, the hybrid electronic control unit 70 is connected to the engine ECU 24, the motor ECU 40, and the battery ECU 52 via the communication port, and exchanges various control signals and data with the engine ECU 24, the motor ECU 40, and the battery ECU 52. ing.

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

  Next, during the operation of the hybrid vehicle 20 of the embodiment configured as described above, in particular, while the engine 22 is stopped and only the power from the motor MG2 is running, any one of the drive wheels 63a and 63b slips due to idling. The operation when this occurs will be described. FIG. 2 is a flowchart showing an example of a drive control routine executed by the hybrid electronic control unit 70. This routine is repeatedly executed every predetermined time (for example, every several msec).

  When the drive control routine is executed, first, the CPU 72 of the hybrid electronic control unit 70 first determines the accelerator opening Acc from the accelerator pedal position sensor 84, the vehicle speed V from the vehicle speed sensor 88, the rotational speed Nm1, of the motors MG1, MG2. Nm2, input / output restrictions Win and Wout of the battery 50, charging / discharging required power Pb *, wheel speeds Vl and Vr from the wheel speed sensors 64a and 64b, and other data necessary for control are 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 input / output limits Win and Wout of the battery 50 are set based on the battery temperature Tb of the battery 50 detected by the temperature sensor 51 and the remaining capacity (SOC) of the battery 50 from the battery ECU 52 by communication. To do. The input / output limits Win and Wout of the battery 50 are set to basic values of the input / output limits Win and Wout based on the battery temperature Tb, and the output limiting correction coefficient and the input limiting limit are set based on the remaining capacity (SOC) of the battery 50. The correction coefficient is set, and the input / output limits Win and Wout can be set by multiplying the basic values of the set input / output limits Win and Wout by the correction coefficient. FIG. 3 shows an example of the relationship between the battery temperature Tb and the input / output limits Win, Wout, and FIG. 4 shows an example of the relationship between the remaining capacity (SOC) of the battery 50 and the correction coefficients of the input / output limits Win, Wout. Further, the charge / discharge required power Pb * is set based on the remaining capacity (SOC) of the battery 50 and is input from the battery ECU 52 by communication.

  When the data is thus input, the required torque Tr * to be output to the ring gear shaft 32a as the drive shaft connected to the drive wheels 63a and 63b as the torque required for the vehicle based on the input accelerator opening Acc and the vehicle speed V. And the required power Pe * required for the engine 22 is set (step S110). In the embodiment, the required torque Tr * is determined in advance by storing the relationship between the accelerator opening Acc, the vehicle speed V, and the required torque Tr * in the ROM 74 as a required torque setting map, and the accelerator opening Acc, the vehicle speed V, , The corresponding required torque Tr * is derived and set from the stored map. FIG. 5 shows an example of the required torque setting map. The required power Pe * can be calculated as the sum of the set required torque Tr * multiplied by the rotational speed Nr of the ring gear shaft 32a and the charge / discharge required power Pb * required by the battery 50 and the loss Loss. The rotation speed Nr of the ring gear shaft 32a can be obtained by multiplying the vehicle speed V by the conversion factor k, or can be obtained by dividing the rotation speed Nm2 of the motor MG2 by the gear ratio Gr of the reduction gear 35.

  Next, a value of a slip start flag Fslip set by a slip suppression process (step S210) described later is checked (step S120), and the set required power Pe * is compared with a threshold value Pref (step S130). Here, the slip start flag Fslip is set such that one of the drive wheels 63a and 63b slips while the engine 22 is running only with the power from the motor MG2 and the engine 22 is stopped. A value of 1 is set when starting 22 and a value of 0 is set when such a slip converges. The threshold value Pref is set as a threshold value for starting the engine 22 or stopping its operation. In the embodiment, for ease of explanation, the engine 22 is started or stopped by comparing the required power Pe * and the threshold value Pref. However, in addition to the required power Pe *, the remaining battery 50 The engine 22 may be started or stopped in consideration of the capacity (SOC), the vehicle speed V, and the like.

  When the slip start flag Fslip is set to 0 because no slip has occurred in any of the drive wheels 63a and 63b and the set required power Pe * is less than the threshold value Pref, the operation of the engine 22 is stopped. In addition, a value 0 is set for the target rotational speed Ne * and the target torque Te * of the engine 22 (step S140), and a value 0 is also set for the torque command Tm1 * of the motor MG1 (step S150). In the embodiment, the value 0 is set to the target rotational speed Ne *, the target torque Te *, and the torque command Tm1 * for confirmation even when the engine 22 is already stopped.

  On the other hand, when no slip has occurred in any of the drive wheels 63a and 63b, a value 0 is set in the slip start flag Fslip and the required power Pe * is equal to or greater than the threshold value Pref, or any of the drive wheels 63a and 63b. When the engine slip is caused and the engine 22 is started, the target rotational speed Ne * and the target torque Te * of the engine 22 are set based on the set required power Pe * (step S160). In this setting, the target rotational speed Ne * and the target torque Te * are set based on the operation line for efficiently operating the engine 22 and the required power Pe *. FIG. 6 shows an example of the operation line of the engine 22 and how the target rotational speed Ne * and the target torque Te * are set. As shown in the figure, the target rotational speed Ne * and the target torque Te * can be obtained from the intersection of the operation line and a curve with a constant required power Pe * (Ne * × Te *). Subsequently, using the set target rotational speed Ne *, the rotational speed Nr (Nm2 / Gr) of the ring gear shaft 32a, and the gear ratio ρ of the power distribution and integration mechanism 30, the target rotational speed Nm1 of the motor MG1 is given by the following equation (1). * Is calculated and a torque command Tm1 * of the motor MG1 is calculated by equation (2) based on the calculated target rotational speed Nm1 * and the current rotational speed Nm1 (step S170). Here, Expression (1) is a dynamic relational expression for the rotating element of the power distribution and integration mechanism 30. FIG. 7 shows 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 in a state where the operation of the engine 22 is stopped, and the power distribution in the state where the engine 22 is operating. FIG. 8 is a collinear diagram showing the dynamic relationship between the rotational speed and torque in the rotating elements of the integrated mechanism 30. In the figure, the left S-axis indicates the rotation speed of the sun gear 31 that is the rotation speed Nm1 of the motor MG1, the C-axis indicates the rotation speed of the carrier 34 that is the rotation speed Ne of the engine 22, and the R-axis indicates the rotation speed of the motor MG2. The rotational speed Nr of the ring gear 32 obtained by multiplying the number Nm2 by the gear ratio Gr of the reduction gear 35 is shown. Equation (1) can be easily derived by using the alignment chart of FIG. Note that the two thick arrows on the R axis in FIG. 8 indicate that the torque Te * output from the engine 22 when the engine 22 is steadily operated at the operation point of the target rotational speed Ne * and the target torque Te * is the ring gear shaft. The torque transmitted to 32a and the torque that the torque Tm2 * output from the motor MG2 acts on the ring gear shaft 32a via the reduction gear 35 are shown. Expression (2) is a relational expression in feedback control for rotating the motor MG1 at the target rotational speed Nm1 *. In Expression (2), “k1” in the second term on the right side is a gain of a proportional term. “K2” in the third term on the right side is the gain of the integral term.

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

  When the target rotational speed Nm1 * of the motor MG1 and the torque command Tm1 * are calculated, the motor MG1 obtained by multiplying the output limit Wout of the battery 50 and the calculated torque command Tm1 * of the motor MG1 by the current rotational speed Nm1 of the motor MG1. The torque limits Tmin and Tmax as upper and lower limits of the torque that may be output from the motor MG2 by dividing the deviation from the power consumption (generated power) by the rotation speed Nm2 of the motor MG2 are expressed by the following equations (3) and (4): ) (Step S180), and using the required torque Tr *, torque command Tm1 *, and gear ratio ρ of the power distribution and integration mechanism 30, a temporary motor torque Tm2tmp as a torque to be output from the motor MG2 is expressed by equation (5). (Step S190), and the provisional motor torque Tm with the calculated torque limits Tmin and Tmax. Limiting the tmp sets the torque command Tm2 * of the motor MG2 (step S200). By setting the torque command Tm2 * of the motor MG2 in this way, the required torque Tr * output to the ring gear shaft 32a as the drive shaft is set as a torque limited within the range of the input / output limits Win and Wout of the battery 50. can do. Equation (5) can be easily derived from the collinear diagram of FIG. 8 described above.

Tmin ＝ (Win−Tm1 * ・ Nm1) / Nm2 (3)
Tmax ＝ (Wout−Tm1 * ・ Nm1) / Nm2 (4)
Tm2tmp = (Tr * + Tm1 * / ρ) / Gr (5)

  When the target rotational speed Ne * and target torque Te * of the engine 22 and the torque commands Tm1 * and Tm2 * of the motors MG1 and MG2 are thus set, the slip suppression process illustrated in FIG. 9 is executed (step S210). The target rotational speed Ne * and the target torque Te * are transmitted to the engine ECU 24, and the torque commands Tm1 * and Tm2 * of the motors MG1 and MG2 are transmitted to the motor ECU 40 (step S220), and the drive control routine is terminated. The engine ECU 24 that has received the target rotational speed Ne * and the target torque Te * performs fuel injection control in the engine 22 such that the engine 22 is operated at an operating point indicated by the target rotational speed Ne * and the target torque Te *. Controls such as ignition control. Here, when the engine ECU 24 receives the target rotational speed Ne * and the target torque Te * having a value of 0, the engine ECU 24 stops the operation when the engine 22 is operated, and operates when the engine 22 is stopped. Maintain a stop state. Further, when the engine ECU 24 receives the target rotational speed Ne * and the target torque Te * that are not 0 when the engine 22 is in a stopped state, the engine ECU 24 starts the engine 22 and then the engine 22 Control is performed so that the vehicle is operated at the operation point indicated by the rotational speed Ne * and the target torque Te *. The engine 22 is started by outputting the torque required for cranking the engine 22 from the motor MG1, and canceling the torque output to the ring gear shaft 32a with the torque output from the motor MG1 and the sum of the required torque Tr. This is done by outputting torque from the motor MG2. Since the start control of the engine 22 does not form the core of the present invention, further explanation is omitted. 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.

  In the slip suppression process illustrated in FIG. 9, first, the rotational angular acceleration α is calculated based on the rotational speed Nm2 of the motor MG2 (step S300), and the idle rotation of one of the drive wheels 63a and 63b is performed based on the rotational angular acceleration α. It is determined whether or not slip has occurred due to (step S310). In the embodiment, the determination of slip is made by comparing the rotational angular acceleration α with a threshold value, determining that slip has occurred when the rotational angular acceleration α exceeds the threshold value, and rotating angular acceleration when the rotational angular acceleration α exceeds the threshold value. Even if α is less than the threshold value, it is determined that slip has occurred until a predetermined time (for example, time of 0.5 seconds or 1 second) elapses. This is because the slip is likely to occur even when the rotational angular acceleration α is less than the threshold value, so that the slip is immediately prevented from occurring again. If it is determined that no slip has occurred (step S320), the slip start flag Fslip is set to 0 (step S330), and the process ends.

  On the other hand, when it is determined that slip has occurred (step S320), it is determined whether or not the motor travel is performed only by the power from the motor MG2 with the engine 22 stopped (step S340). When the motor is running, a torque upper limit value Tslip is set as an upper limit of torque that may be output from the motor MG2 in order to suppress slipping based on the rotational angular acceleration α (step S350). In the embodiment, the relationship between the rotational angular acceleration α and the torque upper limit value Tslip is determined in advance and stored in the ROM 74 as a torque upper limit value setting map, and when the rotational angular acceleration α is given, the corresponding torque upper limit value Tslip is determined from the map. Was derived and set. An example of the torque upper limit setting map is shown in FIG. In the example of FIG. 10, the torque upper limit value Tslip is set to be smaller as the rotational angular acceleration α is larger. When the torque upper limit value Tslip is set, the torque command Tm2 * of the motor MG2 is reset so as to be within the set torque upper limit value Tslip (step S360), and an instruction is output to the engine ECU 24 to start the engine 22. (Step S370), it is determined whether or not the engine 22 has been started (step S380). Even if an instruction is output to the engine ECU 24 to start the engine 22, the start of the engine 22 is not completed immediately. Therefore, until the start of the engine 22 is completed, the processes from step S350 to S380 are executed and the slip suppression process is terminated. To do. Thus, by limiting the torque command Tm2 * of the motor MG2 with the torque upper limit value Tslip, the slip of the drive wheels 63a and 63b during the motor traveling can be converged. Further, while the torque command Tm2 * of the motor MG2 is thus limited by the torque upper limit value Tslip, the power consumption of the motor MG2 is relatively small. Therefore, by starting the engine 22 during this time, It can be suppressed that the sum of the electric power consumed by the motor MG2 and the electric power necessary for starting the engine 22 becomes an excessive electric power. As a result, it is possible to suppress discharge due to excessive electric power of the battery 50 that is generated when the engine 22 is started while relatively large electric power is consumed by the motor MG2.

  If the start of the engine 22 is completed during the slip suppression control during the running of the motor, an affirmative determination is made in step S380, and a value 1 is set in the slip start flag Fslip (step S390). When the value 1 is set to the slip start flag Fslip, the processing of steps S160 and S170 for continuing the operation of the engine 22 is executed in the drive control routine of FIG. 2 regardless of the required power Pe *.

  If it is determined in step S320 that slip has occurred in the drive wheels 63a and 63b, and if it is determined in step S330 that the motor is not running, slip suppression control is performed by hydraulic brakes 66a and 66b (step S400). Then, the slip suppression process ends. In the embodiment, the slip suppression control by the hydraulic brakes 66a and 66b is determined by determining the driving wheel causing the slip based on the wheel speeds Vl and Vr detected by the wheel speed sensors 64a and 64b, and driving causing the slip. A so-called traction control that suppresses slip by applying a braking force to the wheel is used.

  Consider a case in which one of the drive wheels 63a and 63b slips due to idling while trying to start on a low μ road such as a snowy road by motor running. In this case, the required torque Tr * is set based on the accelerator opening Acc and the vehicle speed V (step S110), and the torque command Tm2 * of the motor MG2 is set within the range of the input / output limits Win and Wout of the battery 50. (Step S220), the set torque command Tm2 * is limited by the torque upper limit value Tslip according to the rotational angular acceleration α of the rotation shaft of the motor MG2 by the slip suppression process (step S360). For this reason, the generated slip converges. In such slip suppression control, the required torque Tr * to be output to the ring gear shaft 32a as the drive shaft is limited, so that it is sufficient not only for drive wheels that have slipped but also drive wheels that have not slipped. The driving force cannot be output. For this reason, it is difficult to start on a slope starting on a low μ road such as a snowy road. In the embodiment, when the restriction of the torque command Tm2 * by the torque upper limit value Tslip is started, the engine 22 is started regardless of the required power Pe *, and when the start of the engine 22 is completed, slip suppression by the hydraulic brakes 66a and 66b is performed. Take control. Since the slip suppression control by the brakes 66a and 66b suppresses slip by applying a braking force to the drive wheels where slip occurs, the required torque Tr * is output to the ring gear shaft 32a as the drive shaft. As a result, a sufficient driving force can be output to the drive wheels that are not slipping. For this reason, it is possible to start with the driving force of the drive wheels that do not cause slip even when starting on a slope on a low μ road such as a snowy road. It should be noted that the timing at which the engine 22 is started is the timing at which the restriction of the torque command Tm2 * by the torque upper limit value Tslip is started, so that the sum of the power consumed by the motor MG2 and the power required for starting the engine 22 is excessive. It can suppress becoming electric power, and the discharge by the excessive electric power of the battery 50 can be suppressed.

  According to the hybrid vehicle 20 of the embodiment described above, when slipping due to idling occurs in any of the drive wheels 63a and 63b during motor running, the slip is suppressed and the engine 22 is controlled by limiting the torque from the motor MG2. Is switched to the slip suppression control by the brakes 66a and 66b, so that the slip can be suppressed and the required torque Tr * requested by the driver without the discharge due to excessive electric power of the battery 50 is used as the drive shaft. It can output to the ring gear shaft 32a.

  In the hybrid vehicle 20 of the embodiment, the brakes 66a and 66b are operated by hydraulic pressure, but the brakes 66a and 66b may be operated using actuators other than hydraulic pressure.

  In the hybrid vehicle 20 of the embodiment, the power of the engine 22 is output to the ring gear shaft 32a as the drive shaft connected to the drive wheels 63a and 63b via the power distribution and integration mechanism 30, but the modified example of FIG. The hybrid vehicle 220 includes an inner rotor 232 connected to the crankshaft 26 of the engine 22 and an outer rotor 234 connected to a drive shaft that outputs power to the drive wheels 63a and 63b. A counter-rotor motor 230 that transmits a part of the power to the drive shaft and converts the remaining power into electric power may be provided. Further, since it is only necessary to have a configuration capable of traveling using the power from the internal combustion engine and traveling only using the power from the motor, the drive wheels 63a and 63b are exemplified as illustrated in the hybrid vehicle 320 of the modified example of FIG. Alternatively, a motor 330 may be attached to a drive shaft connected via a differential gear via a transmission 340, and a crankshaft of the engine 322 may be connected to a rotary shaft of the motor 330 via a clutch 328.

  The embodiments of the present invention have been described using the embodiments. However, the present invention is not limited to these embodiments, and can be implemented in various forms without departing from the gist of the present invention. Of course you get.

1 is a configuration diagram showing an outline of a configuration of a hybrid vehicle 20 according to an embodiment of the present invention. It is a flowchart which shows an example of the drive control routine performed by the electronic control unit for hybrids 70 of an Example. It is explanatory drawing which shows an example of the relationship between the battery temperature Tb in the battery 50, and the input / output restrictions Win and Wout. It is explanatory drawing which shows an example of the relationship between the remaining capacity (SOC) of the battery 50, and the correction coefficient of input / output restrictions Win and Wout. It is explanatory drawing which shows an example of the map for request | requirement torque setting. It is explanatory drawing which shows a mode that an example of the operating line of the engine 22, and target rotational speed Ne * and target torque Te * are set. It is explanatory drawing which shows an example of the alignment chart for demonstrating dynamically the rotational element of the power distribution integration mechanism 30 in the state which has stopped operation of the engine 22. FIG. It is explanatory drawing which shows an example of the alignment chart for demonstrating dynamically the rotational element of the power distribution integration mechanism 30 in the state which is operating the engine 22. FIG. It is a flowchart which shows an example of a slip suppression process. It is explanatory drawing which shows an example of the map for torque upper limit setting. FIG. 11 is a configuration diagram showing an outline of a configuration of a hybrid vehicle 220 of a modified example. FIG. 11 is a configuration diagram showing an outline of a configuration of a hybrid vehicle 320 of a modified example.

Explanation of symbols

20, 220, 320 Hybrid vehicle, 22 engine, 24 engine electronic control unit (engine ECU), 26 crankshaft, 28 damper, 30 power distribution integration mechanism, 31 sun gear, 32 ring gear, 32a ring gear shaft, 33 pinion gear, 34 carrier 35, reduction gear, 40 motor electronic control unit (motor ECU), 41, 42 inverter, 43, 44 rotational position detection sensor, 50 battery, 51 temperature sensor, 52 battery electronic control unit (battery ECU), 54 power line , 60 gear mechanism, 62 differential gear, 63a, 63b drive wheel, 64a, 64b wheel speed sensor, 66a, 66b brake, 70 hybrid electronic control unit, 72 CPU, 74 ROM, 76 RAM, 80 Igni 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, 230 to rotor motor, 232 inner rotor 234 outer rotor, 322 engine 328 clutch, 330 motor, 340 transmission, MG1, MG2 motor.

Claims (6)

An internal combustion engine capable of outputting power to a drive shaft connected to an axle;
An electric motor capable of outputting power to the drive shaft;
Power storage means capable of exchanging electric power with the motor;
Slip determination means for determining that slippage due to idling has occurred in any of the left and right drive wheels connected to the axle;
Braking force application means for individually applying a braking force to the left and right drive wheels;
When the slip determination means determines that one of the left and right drive wheels has slipped while the internal combustion engine is not operating, the power output to the drive shaft is limited to suppress the slip. The internal combustion engine is controlled such that the electric motor is controlled and the internal combustion engine is started, and after the internal combustion engine is started, the braking force is applied to the drive wheel in which the slip is determined in order to suppress the slip. Control means for controlling the braking force application means so as to be acted on and controlling the internal combustion engine and the electric motor so that power is output to the drive shaft;
A hybrid car with The hybrid vehicle according to claim 1,
Requested power setting means for setting required power to be output to the drive shaft based on the operation of the driver;
Start / stop determination means for determining start and stop of the internal combustion engine based on the set required power;
With
The control means executes the determination result by the start / stop determination means when the slip determination means determines that no slip is detected in any of the left and right drive wheels, and the power based on the set required power is When the internal combustion engine and the electric motor are controlled so as to be output to the drive shaft, and the slip determination means determines that any of the left and right drive wheels has slipped in a state where the internal combustion engine is stopped. The electric motor is controlled so that power that restricts the set required power in order to suppress slip is output to the drive shaft, and the internal combustion engine is started regardless of the determination result by the start / stop determination means. One of the left and right drive wheels is controlled by the slip determination means while controlling the internal combustion engine and operating the internal combustion engine. When the slip is determined, the braking force application means is controlled so that the braking force is applied to the drive wheel where the slip is determined in order to suppress the slip, and the power based on the set required power is driven. A hybrid vehicle which is means for controlling the internal combustion engine and the electric motor to be output to a shaft. A hybrid vehicle according to claim 1 or 2,
Power power input / output means connected to the output shaft of the internal combustion engine and the drive shaft, and capable of outputting at least part of the power from the internal combustion engine to the drive shaft with input / output of power and power,
The power storage means is means capable of exchanging electric power with the power drive input / output means. Hybrid vehicle.   The power power input / output means is connected to three shafts of the output shaft of the internal combustion engine, the drive shaft, and the rotating shaft, and the remaining shaft based on the power input / output to / from any two of the three shafts The hybrid vehicle according to claim 3, further comprising: a three-axis power input / output unit that inputs / outputs power to / from the power generator and a generator that can input / output power to / from the rotating shaft.   The power drive input / output means has a first rotor connected to the output shaft of the internal combustion engine and a second rotor connected to the drive shaft, and the first rotor and the first rotor The hybrid vehicle according to claim 3, wherein the hybrid vehicle is a counter-rotor electric motor that rotates by relative rotation with the two rotors. An internal combustion engine that can output power to a drive shaft connected to an axle, an electric motor that can output power to the drive shaft, an electric storage means that can exchange electric power with the motor, and left and right drive wheels are individually controlled. A braking force control means for applying power, and a hybrid vehicle control method comprising:
When slippage due to idling occurs in any of the left and right drive wheels connected to the axle while the internal combustion engine is stopped, the power output to the drive shaft is limited to suppress the slip. The internal combustion engine is controlled such that the electric motor is controlled and the internal combustion engine is started, and after the internal combustion engine is started, the slipping wheel is controlled to the drive wheel in which the slip is determined to suppress the slip. A control method for a hybrid vehicle, wherein the braking force application means is controlled so that power is applied, and the internal combustion engine and the electric motor are controlled so that power is output to the drive shaft.

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