JP2013141862A - Hybrid vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To more facilitate acquisition of required torque as a required braking force on the basis of a shift operation during accelerator off.SOLUTION: An engine and two motors are controlled so that a required torque required as a braking force during accelerator off is covered for vehicle running by a braking torque by motoring under an engine fuel cutoff state and a braking torque of a second motor on the power generation side within a range of a battery input limit. In performing a shift change such as a change of a shift position SP from D-position to B position or S position during accelerator off, an input limit Winf for control as an input limit of a battery is changed, for a predetermined time tref period, to an input limit Winf for control with a larger absolute value than before the shift change. Thus, the degree that a required torque as a required braking force on the basis of a shift operation during accelerator off cannot be covered is suppressed.

Description

  The present invention relates to a hybrid vehicle. More specifically, the present invention relates to an engine that outputs driving power, a first motor that can motor the engine, a second motor that can input and output driving power, and a first motor. The present invention relates to a hybrid vehicle including a battery that exchanges electric power with the second motor and the second motor.

  Conventionally, this type of hybrid vehicle includes an engine, a first motor, a drive shaft mechanically connected to an axle, an output shaft of the engine, and a rotation shaft of the first motor, respectively, and ring gears. A shift lever comprising: a planetary gear mechanism in which a carrier and a sun gear are connected; a second motor capable of inputting / outputting power to / from a drive shaft; and a battery for exchanging electric power with the first motor and the second motor. However, when the accelerator is off, the required torque to be output to the drive shaft is smaller than the D (drive) range (the braking force increases), and the required torque decreases (the braking force increases) as the number of steps decreases. When operated to the set B (brake) range, the engine is controlled by the first motor so that the higher the vehicle speed, the higher the engine speed is adjusted. Which Taringu has been proposed (e.g., see Patent Document 1). In this hybrid vehicle, as the number of stages in the B range is reduced and the vehicle speed is increased by the control when operated in the B range, a larger friction power is output from the engine, and the friction power is transmitted to the drive shaft via the planetary gear mechanism. In other words, a large engine brake is applied to the drive shaft.

JP 2006-21622 A

  In the hybrid vehicle described above, when the accelerator is off, the fuel-cut engine is motored by the first motor within the range of the chargeable power (input limit) of the battery, and a so-called engine brake is applied to the drive shaft. There are cases where control is performed to output the braking side (power generation side, negative side) torque to the drive shaft by the motor 2. If such control is performed when the amount of chargeable power of the battery is small, the number of stages in the B range can be increased when the shift lever is operated from the D range to the B range during accelerator-off or when the shift lever is operated. When the number of steps is changed to the lower side, there is a case where the required torque as a braking force desired by the driver when the accelerator is off cannot be sufficiently provided by the engine brake and the torque from the second motor.

  The main purpose of the hybrid vehicle of the present invention is to make it easier to ensure the required torque as the braking force required based on the shift operation when the accelerator is off.

  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 that outputs power for traveling; a first motor that can motor the engine; a second motor that can input and output power for traveling; the first motor and the second motor; In a hybrid vehicle comprising a battery that exchanges power,
The required torque required as a braking force when the accelerator is off is within the range of the allowable charging power of the battery, by the torque due to motoring when the fuel of the engine is cut off and the torque on the power generation side of the second motor Control means for controlling the engine, the first motor and the second motor so as to be covered and traveled;
The control means changes the shift position when the shift position is changed from the first position to the second position larger than the first position when the accelerator is off while the accelerator is off. Sometimes it is a means for setting the charge allowable power of the battery to a power that is larger by a predetermined time than before the shift change,
It is characterized by that.

  In the hybrid vehicle of the present invention, the required torque required as the braking force when the accelerator is off is within the range of the chargeable power of the battery, and the torque generated by motoring in a state where the fuel of the engine is cut off and the power generation of the second motor. The engine, the first motor, and the second motor are controlled so that the vehicle is driven by the torque on the side, and the shift position is requested from the first position when the accelerator is off while the accelerator is off. At the time of a shift change in which the magnitude of the braking force applied is changed to the second position larger than the first position, the charge allowable power of the battery is set to a power that is larger by a predetermined time than before the shift change. As a result, the degree to which the required torque as the braking force required based on the shift operation cannot be covered even when the accelerator is off can be suppressed, that is, the required torque can be more easily secured. Can do. In this case, when the accelerator is off, the control means controls the engine and the first motor so that the engine is motored at a target rotational speed based on a shift position and a vehicle speed. You can also.

  Here, the “chargeable power” can basically be set based on the state of the battery such as the storage ratio, which is the ratio of the storage amount to the battery capacity, and the temperature of the battery. The combination of the “first position” and the “second position” includes a combination of a drive position and a brake position for normal driving, a predetermined position in the sequential shift position, and a position on the downshift side from the predetermined position. Combinations, etc. are included. Further, as the “predetermined time”, a time that is predetermined as a time during which the driver can experience a change in the vehicle braking force can be used.

  In such a hybrid vehicle of the present invention, if the shift position is changed from the first position to the second position while the accelerator is off, the control means uses the charge allowable power of the battery to generate the required torque. Means for controlling the engine and the first motor so that the engine is motored at a rotational speed lower by a predetermined rotational speed than when the shortage is estimated when the shortage is estimated to be covered by There can be. In this case, the control means is means for controlling the engine and the first motor so that when the shift is changed, the speed of increase of the engine speed is higher than that before the shift change. You can also In this way, the engine speed is lowered in advance when the shortage is estimated, and the braking-side torque acting on the vehicle due to the inertia of the rotating system including the engine as the engine speed rises during the subsequent shift change. Can be made larger.

  Here, the estimation of “deficiency estimation” can be performed when the amount of charge allowable power of the battery is less than a power threshold value based on the vehicle speed. Further, the “predetermined number of revolutions” can be a number of revolutions determined in advance for each current number of revolutions of the engine, such that the driver feels uncomfortable.

  In the hybrid vehicle of the present invention, the second motor includes a planetary gear in which a drive shaft coupled to an axle, an output shaft of the engine, and a rotation shaft of the first motor are connected to three rotation elements. The rotation shaft may be connected to the drive shaft.

1 is a configuration diagram showing an outline of a configuration of a hybrid vehicle 20 as an embodiment of the present invention. 4 is a flowchart showing an example of an accelerator-off time control routine executed by an HVECU 70. It is explanatory drawing which shows an example of the map for request | requirement torque setting. It is explanatory drawing which shows an example of the map for target rotation speed setting. It is explanatory drawing which shows an example of the collinear diagram which shows the dynamic relationship between the rotation speed and torque in the rotation element of the planetary gear 30 at the time of driving | running | working motoring the engine 22 fuel-cut by motor MG1. It is explanatory drawing which shows an example of the relationship between battery temperature Tb and the basic value of control input / output restrictions Winf and Woutf. It is explanatory drawing which shows an example of the relationship between the electrical storage ratio SOC of the battery 50, and the correction coefficient of the control input / output restrictions Winf and Woutf. An example of a time change state of the shift position SP when the accelerator is off, the torque acting on the vehicle, the control input limit Winf of the battery 50, the rotational speed Ne of the engine 22 and the power due to the inertia of the rotating system including the engine 22 is shown. It is explanatory drawing.

  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, motor MG2 configured as, for example, a synchronous generator motor with the rotor connected to drive shaft 36, and motors MG1 and MG2 driven by switching of a plurality of switching elements (not shown). Inverters 41 and 4 And a motor electronic control unit (hereinafter referred to as a motor ECU) 40 that controls driving of the motors MG1 and MG2 by switching control of a plurality of switching elements of the inverters 41 and 42, and a lithium ion secondary battery, for example. A battery 50 that exchanges power with the motors MG1 and MG2 via inverters 41 and 42, a battery electronic control unit (hereinafter referred to as a battery ECU) 52 that manages the battery 50, and a hybrid electronic control unit that controls the entire vehicle. (Hereinafter referred to as HVECU) 70.

  Although not shown, the engine ECU 24 is configured as a microprocessor centered on a CPU, and includes a ROM for storing a processing program, a RAM for temporarily storing data, an input / output port, and a communication port in addition to the CPU. . The engine ECU 24 receives signals from various sensors that detect the operating state of the engine 22, for example, a water temperature sensor that detects the crank position θcr from the crank position sensor that detects the rotational position of the crankshaft 26 and the coolant temperature of the engine 22. From the cam position sensor for detecting the cooling water temperature Tw from the cylinder, the in-cylinder pressure Pin from the pressure sensor installed in the combustion chamber, the rotational position of the intake valve for intake and exhaust to the combustion chamber and the camshaft for opening and closing the exhaust valve Position θca, throttle position TP from a throttle valve position sensor that detects the position of the throttle valve, intake air amount Qa from an air flow meter attached to the intake pipe, intake air temperature Ta from a temperature sensor also attached to the intake pipe, Installed in the exhaust system The air-fuel ratio AF from the air-fuel ratio sensor and the oxygen signal O2 from the oxygen sensor attached to the exhaust system are input via the input port, and the engine ECU 24 is for driving the engine 22. Various control signals, such as the drive signal to the fuel injection valve, the drive signal to the throttle motor that adjusts the throttle valve position, the control signal to the ignition coil integrated with the igniter, and the opening / closing timing of the intake valve can be changed A control signal to the variable valve timing mechanism is output via the output port. The engine ECU 24 is in communication with the HVECU 70, controls the operation of the engine 22 by a control signal from the HVECU 70, and outputs data related to the operation state of the engine 22 to the HVECU 70 as necessary. The engine ECU 24 also calculates the rotational speed of the crankshaft 26, that is, the rotational speed Ne of the engine 22 based on a signal from a crank position sensor (not shown) attached to the crankshaft 26.

  Although not shown, the motor ECU 40 is configured as a microprocessor centered on a CPU, and includes a ROM for storing a processing program, a RAM for temporarily storing data, an input / output port, and a communication port in addition to the CPU. . The motor ECU 40 receives signals necessary for driving and controlling the motors MG1 and MG2, for example, rotational positions θm1 and θm2 from rotational position detection sensors 43 and 44 that detect the rotational positions of the rotors of the motors MG1 and MG2, and not shown. A phase current applied to the motors MG1 and MG2 detected by the current sensor is input via the input port, and the motor ECU 40 outputs a switching control signal to switching elements (not shown) of the inverters 41 and 42. It is output through the port. The motor ECU 40 is in communication with the HVECU 70, controls the driving of the motors MG1 and MG2 by a control signal from the HVECU 70, and outputs data related to the operating state of the motors MG1 and MG2 to the HVECU 70 as necessary. The motor ECU 40 also calculates the rotational angular velocities ωm1, ωm2 and 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 sensors 43, 44. ing.

  Although not shown, the battery ECU 52 is configured as a microprocessor centered on a CPU, and includes a ROM for storing a processing program, a RAM for temporarily storing data, an input / output port, and a communication port in addition to the CPU. . The battery ECU 52 receives signals necessary for managing the battery 50, for example, an inter-terminal voltage Vb from a voltage sensor (not shown) installed between the terminals of the battery 50 and a power line connected to the output terminal of the battery 50. The charging / discharging current Ib from the attached current sensor (not shown), the battery temperature Tb from the temperature sensor (not shown) attached to the battery 50, and the like are input. Send to. Further, the battery ECU 52 manages the battery 50 based on the integrated value of the charge / discharge current Ib detected by the current sensor, and the ratio of the capacity of the electric power that can be discharged from the battery 50 at that time (the battery 50 The maximum allowable power that can be charged / discharged based on the calculated power storage ratio SOC and the battery temperature Tb (charge allowable power, discharge allowable power) The input / output limits Win and Wout are calculated. The input / output limits Win and Wout of the battery 50 are set to the basic values of the input / output limits Win and Wout based on the battery temperature Tb, and the output limiting correction coefficient and the input limiting limit are set based on the storage ratio SOC of the battery 50. It can be set by setting a correction coefficient and multiplying the basic value of the set input / output limits Win and Wout by the correction coefficient.

  Although not shown, the HVECU 70 is configured as a microprocessor centered on a CPU, and includes a ROM for storing a processing program, a RAM for temporarily storing data, an input / output port, and a communication port in addition to the CPU. 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 degree from the accelerator pedal position 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. Further, as described above, the HVECU 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.

  In the hybrid vehicle 20 of the embodiment thus configured, the required torque Tr * to be output to the drive shaft 36 is calculated based on the accelerator opening Acc and the vehicle speed V corresponding to the depression amount of the accelerator pedal by the driver. 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 Tr * is output to the drive shaft 36. As the operation control of the engine 22, the motor MG1, and the motor MG2, the operation of the engine 22 is controlled so that the power corresponding to the required power is output from the engine 22, and all the power output from the engine 22 is transmitted to the planetary gear 30 and the motor. The torque conversion operation mode in which the motor MG1 and the motor MG2 are driven and controlled so that the torque is converted by the MG1 and the motor MG2 and output to the drive shaft 36, and the sum of the required power and the power required for charging and discharging the battery 50 is met. Operation of the engine 22 is controlled so that power is output from the engine 22, and all or part of the power output from the engine 22 with charge / discharge of the battery 50 is torque generated by the planetary gear 30, the motor MG1, and the motor MG2. The required power is output to the drive shaft 36 with conversion. Charge-discharge drive mode for driving and controlling the motors MG1 and MG2, there is a motor operation mode in which operation control to output a power commensurate to stop the operation of the engine 22 to the required power from the motor MG2 to the drive shaft 36. The torque conversion operation mode and the charge / discharge operation mode are modes in which the engine 22, the motor MG1, and the motor MG2 are controlled so that the required power is output to the drive shaft 36 with the operation of the engine 22. Since there is no substantial difference in control, both are hereinafter referred to as the engine operation mode.

  In the engine operation mode, the HVECU 70 sets the required torque Tr * to be output to the drive shaft 36 based on the accelerator opening Acc from the accelerator pedal position sensor 84 and the vehicle speed V from the vehicle speed sensor 88, and the set required torque The travel power Pdrv * required for travel is calculated by multiplying Tr * by the rotational speed Nr of the drive shaft 36 (for example, the rotational speed obtained by multiplying the rotational speed Nm2 of the motor MG2 and the vehicle speed V by the conversion factor). The power to be output from the engine 22 by subtracting the charge / discharge required power Pb * (positive value when discharging from the battery 50) of the battery 50 obtained from the calculated traveling power Pdrv * based on the storage ratio SOC of the battery 50 Is set as the required power Pe *. Then, the target rotational speed Ne of the engine 22 is obtained using an operation line (for example, a fuel efficiency optimal operation line) as a relationship between the rotational speed Ne of the engine 22 and the torque Te that can efficiently output the required power Pe * from the engine 22. * And the target torque Te * are set, and the motor is controlled by the rotational speed feedback control so that the rotational speed Ne of the engine 22 becomes the target rotational speed Ne * within the range of the input / output limits Win and Wout of the battery 50. A torque command Tm1 * as a torque to be output from MG1 is set, and when the motor MG1 is driven by the torque command Tm1 *, the torque acting on the drive shaft 36 via the planetary gear 30 is subtracted from the required torque Tr * to reduce the motor MG2. Torque command Tm2 * is set, and the target rotational speed Ne * and target torque Te * are set. In its sent to the engine ECU 24, the torque command Tm1 *, the Tm2 * is sent 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 *. The motor ECU 40 that performs the control and receives 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 *. .

  In the motor operation mode, the HVECU 70 sets a required torque Tr * to be output to the drive shaft 36 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 sets the battery 50. The torque command Tm2 * of the motor MG2 is set and transmitted to the motor ECU 40 so that the required torque Tr * is output to the drive shaft 36 within the range of the input / output limits Win, Wout. The motor ECU 40 that receives 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 *.

  Further, in the hybrid vehicle 20 of the embodiment, as the shift position SP of the shift lever 81, a parking position (P position) used during parking, a reverse position (R position) for reverse travel, a neutral position (N position), a forward position In addition to the normal driving position (D position) for driving, the setting of the driving force when the accelerator is on is the same as the D position, but the braking force that is applied to the vehicle when the accelerator is off during driving is set larger than the D position. A sequential shift position (S position) having a brake position (B position), an upshift instruction position, and a downshift instruction position is prepared. Here, the S position is a position for changing the driving force when the accelerator is on and the braking force when the accelerator is off during traveling, for example, in six steps (S1 to S6), and the upshift instruction position is operated to upshift. The driving force when the accelerator is on and the braking force when the accelerator is off during traveling are reduced each time, and the driving force when the accelerator is on and the braking when the accelerator is off during traveling each time a downshift is performed by operating the downshift instruction position. The power increases. In the embodiment, at the B position and the S position, when the accelerator is turned off during traveling, the engine 22 is forcibly rotated by motoring the motor 22 with the motor MG1 while the fuel injection is stopped. Brake control that causes resistance to act on the drive shaft 36 as braking force and brake control that causes the braking force to act on the drive shaft 36 by regenerative control of the motor MG2 are used in combination. In the embodiment, when the shift position SP is changed from the D position to the S position, S3 is selected as the shift position SP.

  Next, the operation of the hybrid vehicle 20 of the embodiment thus configured, particularly the operation when the accelerator is off will be described. FIG. 2 is a flowchart showing an example of an accelerator-off time control routine executed by the HVECU 70. This routine is repeatedly executed every predetermined time (for example, every several milliseconds) when the accelerator is off.

When the accelerator off time control routine is executed, the CPU 72 of the HVECU 70 first
The shift position SP from the shift position sensor 82, the vehicle speed V from the vehicle speed sensor 88, the rotational speed Ne of the engine 22, the rotational speeds Nm1 and Nm2 of the motors MG1 and MG2, the storage rate SOC of the battery 50, the battery temperature Tb, and input / output restrictions Processing for inputting data necessary for control such as Win and Wout is executed (step S100). Here, the rotational speed Ne of the engine 22 is calculated based on the crank position θcr, which is the rotational position of the crankshaft 26 detected by a crank position sensor (not shown), and is input from the engine ECU 24 by communication. Further, the rotational speeds Nm1 and Nm2 of the motors MG1 and MG2 are calculated from the rotational positions θm1 and θm2 of the rotors of the motors MG1 and MG2 detected by the rotational position detection sensors 43 and 44, and communicated from the motor ECU 40. It was supposed to be entered by Further, the storage ratio SOC of the battery 50 is calculated based on the charge / discharge current Ib from the current sensor attached to the power line from the battery 50, and the battery temperature Tb of the battery 50 is attached to the battery 50. The input / output limits Win and Wout of the battery 50 are set based on the battery temperature Tb of the battery 50 and the storage ratio SOC of the battery 50, respectively, by communication from the battery ECU 52. It was supposed to be entered. In the embodiment, the input limit Win of the battery 50 is set within a range of 0 or less, and the output limit Wout of the battery 50 is set within a range of 0 or more.

  When the data is input in this way, the required torque Tr * to be output to the drive shaft 36 connected to the drive wheels 38a and 38b is set as the torque required for the vehicle based on the input vehicle speed V and the shift position SP (step) S110). In the embodiment, the required torque Tr * is determined in advance by storing the relationship between the vehicle speed V, the shift position SP, and the required torque Tr * when the accelerator is off in a ROM (not shown) as a required torque setting map. When the shift position SP is given, the corresponding required torque Tr * is derived and set from the stored map. FIG. 3 shows an example of the required torque setting map. As shown in the figure, the required torque Tr * when the accelerator is off tends to decrease (the braking force increases) as the vehicle speed V increases, and is smaller than when the shift position SP is in the B position than in the D position. (Increases as a braking force) and, when the shift position SP is at the S position, the smaller the number of steps from S6 to S1, the smaller is the tendency to increase (as the braking force increases).

  Subsequently, based on the input vehicle speed V and the shift position SP, the target engine speed Nettag which is a target value of the engine speed at which the fuel injection is stopped (fuel cut) is forcibly rotated by motoring. (Step S120), and the target increase rate ΔNup when increasing the engine speed Ne toward the target engine speed Netag is set in advance for normal control when the accelerator is off based on the characteristics of the engine 22 and the like. A first rate ΔN1 determined by experiment or the like is set (step S130). In the embodiment, the target engine speed Nettag of the engine 22 is stored in a ROM (not shown) as a target engine speed setting map by predetermining the relationship among the vehicle speed V, the shift position SP, and the target engine speed Netag. When the shift position SP is given, the corresponding target rotational speed Nettag is derived and set from the stored map. FIG. 4 shows an example of the target rotation speed setting map. As shown in the figure, the target rotational speed Netag tends to increase as the vehicle speed V increases so as to approximate the engine brake of a vehicle equipped with a manual transmission (manual transmission), and the shift position SP is set to the B position or S. The position is higher than that at the D position, and when the shift position SP is at the S position, it is determined to increase from S6 to S1 as the number of steps decreases.

  Next, when the input shift position SP is changed from the D position to the B position or S position, or the shift position SP is in the S position, the position is changed to a lower position (for example, from S3 to S2 or S1). It is determined whether or not it has been downshifted (hereinafter referred to as a shift change) (step S140), and whether or not a predetermined time tref has elapsed since it was determined immediately before the shift change (step S140). S150). The determination of whether or not it is a shift change can be made by comparing the shift position SP inputted when this routine was executed last time with the shift position SP inputted when this routine was executed this time. A battery that uses the input / output limits Win and Wout of the input battery 50 for control when the accelerator is off when the predetermined time period tref has elapsed since it was determined that the shift was not changed and the shift change was determined immediately before 50 control input / output limits Winf and Woutf are set (step S160). Here, in the embodiment, the predetermined time tref is determined in advance through experiments or the like as a relatively short time during which the driver can feel the change in the braking force of the vehicle by the control when the accelerator is off (for example, 1.5 seconds). And 2 seconds, 3 seconds, etc.).

  When the control input / output limits Winf and Woutf for the battery 50 are set in this way, it is determined whether or not it is estimated that the required torque Tr * is not covered by the input limit Win of the battery 50 if the shift is changed. (Step S170) When so estimated (hereinafter referred to as insufficient estimation), a value obtained by subtracting the predetermined rotation speed Nref from the set target rotation speed Nettag of the engine 22 is reset as the target rotation speed Netag. (Step S180), if not so, the next processing is performed as it is. Here, the estimation at the time of shortage estimation is that the required torque Tr * as the braking force is within the range of the input limit Win of the battery 50 and the motor 22 torque is reduced by the motoring and the motor MG2 regenerative control. This is to estimate a state in which the required torque Tr * cannot be provided due to the input limit Win of the battery 50 when the torque is to be covered by the torque on the side (braking side, negative side). In this embodiment, the estimation is performed by applying the current vehicle speed V to a map in which the relationship between the vehicle speed V and the power threshold value of the input restriction Win that may cause a shortage is determined in advance through experiments or the like. A threshold is derived, and the derived power threshold is compared with the current input limit Win of the battery 50, which is insufficient when the current input limit Win of the battery 50 is greater than this power threshold (the absolute value of the input limit Win is small). It was determined by determining that it was an estimation time. In addition, in the embodiment, the predetermined rotational speed Nref is a rotational speed at which the driver's uncomfortable feeling caused by lowering the target rotational speed Netag of the engine 22 and lowering the rotational speed Ne of the engine 22 falls within an allowable range. For example, a rotational speed (for example, several hundred rpm) determined in advance by experiment or the like for each current rotational speed Ne of the engine 22 is used as the decrease. The reason why the target rotational speed Nettag of the engine 22 is lowered by the predetermined rotational speed Nref when the shortage is estimated in this way will be described later.

  Subsequently, the control target rotation speed Ne * of the engine 22 used for the control at the time of accelerator off is set using the set target rotation speed Netag and the target increase rate ΔNeup (step S210), and the set control target rotation speed Ne * and When the fuel cut command for the engine 22 has not been transmitted, the fuel cut command is transmitted to the engine ECU 24 (step S220). The engine ECU 24 that has received the fuel cut command stops fuel injection control and ignition control of the engine 22. Here, in the embodiment, the target rotational speed Ne * of the engine 22 is set as it is when the target rotational speed Netag of the engine 22 is smaller than the current rotational speed Ne (when the rotational speed is reduced). When the target engine speed Nettag of the engine 22 is larger than the current engine speed Neg (when the engine speed is increased), the control target engine speed Ne * is calculated by applying a rate process with the target increase rate ΔNewup to the set target engine speed Netag. It was supposed to be set. That is, the control target rotation speed Ne * is set so that the rotation speed Ne increases at the set target increase rate ΔNeup when the rotation speed increases the rotation speed Ne of the engine 22 toward the target rotation speed Netag.

  When the control target rotational speed Ne * of the engine 22 is thus set, the control target rotational speed Ne * of the engine 22, the rotational speed Nm2 of the motor MG2, and the gear ratio of the planetary gear 30 (the number of teeth of the sun gear / the number of teeth of the ring gear) ρ are obtained. Using the following equation (1), the target rotational speed Nm1 * of the motor MG1 is calculated and output from the motor MG1 by the formula (2) based on the calculated target rotational speed Nm1 * and the input rotational speed Nm1 of the motor MG1. A torque command Tm1 * to be calculated is calculated (step S230). Here, Expression (1) is a dynamic relational expression for the rotating element of the planetary gear 30. FIG. 5 shows an example of a collinear diagram showing the dynamic relationship between the rotational speed and torque of the rotating element of the planetary gear 30 when the engine 22 that has been fuel-cut by the motor MG1 is motored. 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. (Rotational speed of the drive shaft 36), that is, the rotational speed of the ring gear. Note that the two thick arrows on the R axis indicate that the torque Tm1 output from the motor MG1 for motoring the engine 22 acts on the drive shaft 36 and the torque Tm2 output from the motor MG2 is the drive shaft. The braking torque acting on 36 is shown. Expression (1) can be easily derived by using this alignment chart. 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 / ρ (1)
Tm1 * = previous Tm1 * + k1 (Nm1 * -Nm1) + k2∫ (Nm1 * -Nm1) dt (2)

  Then, by adding the torque command Tm1 * divided by the gear ratio ρ of the planetary gear 30 to the required torque Tr *, a temporary motor torque Tm2tmp that is a temporary value of torque to be output from the motor MG2 is calculated by the following equation (3). (Step S240), and the deviation from the power consumption of the motor MG1 obtained by multiplying the set torque command Tm1 * by the control input / output limits Winf and Woutf for the battery 50 and the current rotational speed Nm1 of the motor MG1 Torque limits Tm2min and Tm2max as upper and lower limits of torque that may be output from the motor MG2 by dividing by the rotational speed Nm2 are calculated by the following equations (4) and (5) (step S250), and the set temporary motor The torque Tm2tmp is limited by the torque limits Tm2min and Tm2max by the equation (6). And sets the torque command Tm2 * of the chromatography data MG2 (step S260), the torque command Tm1 * set, by sending Tm2 * to the motor ECU 40 (step S270), and terminates this routine. Receiving the torque commands Tm1 * and Tm2 *, the motor ECU 40 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 *. . By such control, when the shift position SP is not changed at the time of changing from the D position to the B position, or when the predetermined time tref has passed since the last shift change, the input limit Win of the battery 50 is set. The required torque Tr * as a braking force can be applied to the drive shaft 36 by the torque generated by the motoring of the engine 22 and the power generation side torque of the motor MG2 within the range of the control input limit Winf. Good feeling can be given. If it is estimated that the required torque Tr * will be insufficient if the shift is changed, the target rotational speed Nettag of the engine 22 is determined from the target rotational speed Nettag based on the vehicle speed V and the shift position SP. The motor MG1 is controlled such that the engine 22 is motored at the control target rotational speed Ne * for setting the target rotational speed Netag lower by the rotational speed Nref.

Tm2tmp = Tr * + Tm1 * / ρ (3)
Tm2min = (Win-Tm1 * ・ Nm1) / Nm2 (4)
Tm2max = (Wout-Tm1 * ・ Nm1) / Nm2 (5)
Tm2 * = max (min (Tm2tmp, Tm2max), Tm2min) (6)

  When the shift position SP is changed from the D position to the B position in steps S140 and S150, or when the predetermined time tref has not elapsed since the previous shift change, the storage ratio SOC of the battery 50 is Based on the battery temperature Tb, the control input limits Winf and Woutf are set such that the absolute power is larger than the current input / output limits Win and Wout of the battery 50 (step S190), and the target increase rate ΔNup of the engine 22 is set. As a result, a second rate ΔN2 larger than the first rate ΔN1 for normal control is set (step S200). Here, in the embodiment, the control input / output limits Winf and Woutf are set based on the battery temperature Tb, and the basic values of the control input / output limits Winf and Woutf are set and output based on the storage ratio SOC of the battery 50. The limiting correction coefficient and the input limiting correction coefficient are set, and the basic values of the set control input / output limits Winf and Woutf are multiplied by the correction coefficient. FIG. 6 shows an example of the relationship between the battery temperature Tb and the basic values of the control input / output limits Winf and Woutf, and FIG. 7 shows the relationship between the storage ratio SOC of the battery 50 and the correction coefficients of the control input / output limits Winf and Woutf. An example is shown. In FIG. 6, the transient input / output limits Winset and Woutset indicated by solid lines have power values determined as absolute values larger than the basic values of the input / output limits Win and Wout of the battery 50 indicated by broken lines for reference. The basic values of the transient input / output limits Winset and Woutset are used as the basic values of the control input / output limits Winf and Woutf. Further, the correction coefficients for the control input / output limits Winf and Woutf shown in FIG. 7 are the same as the correction coefficients for the input / output limits Win and Wout of the battery 50.

  When the control input / output limits Winf and Woutf for the battery 50 and the target increase rate ΔNup of the engine 22 are set in this way, the control target rotation rate Ne * of the engine 22 is set using the set target rotation rate Netag and the target increase rate ΔNeup. Is transmitted to the engine ECU 24 together with a fuel cut command as necessary (steps S210 and S220), and the target of the motor MG1 is set so that the rotational speed Ne of the engine 22 becomes the control target rotational speed Ne *. The rotational speed Nm1 * and the torque command Tm1 * are set (step S230), and the required torque Tr * acts on the drive shaft 36 together with the torque acting from the motor MG1 within the range of the control input / output limits Winf and Woutf for the battery 50. To set the torque command Tm2 * of the motor MG2 (step S 240 to S260), torque commands Tm1 * and Tm2 * are transmitted to the motor ECU 40 (step S270), and this routine is terminated.

  FIG. 8 shows how the shift position SP when the accelerator is off, the torque acting on the vehicle, the input limit Winf for controlling the battery 50, the rotational speed Ne of the engine 22 and the power due to the inertia of the rotating system including the engine 22 are changed over time. It is explanatory drawing which shows an example. In the example of FIG. 8, first, the shift position SP is in the D position while the accelerator is off. In this state, the absolute value of the input limit Win of the battery 50 is small, so When the shortage is estimated to occur (time t1), the engine 22 is motored by the control target rotational speed Netag of the engine 22 being reduced by a predetermined rotational speed Nref from the rotational speed based on the vehicle speed V and the shift position SP. The rotational speed Ne at the time of turning is low. Thereafter, when the shift position SP is changed from the D position to the B position (time t2), the control input limit Winf whose absolute value is smaller than the input limit Win of the battery 50 is set for a predetermined time tref (time t2-t3). During the predetermined time period tref, the target target rotational speed Ne * of the engine 22 is increased toward the target rotational speed Netag based on the vehicle speed V and the shift position SP (the B position after the shift change). By increasing at a second rate ΔN2) greater than the rate ΔN1, the rotational speed Ne when the engine 22 is motored increases (time t2-t3). In the example of FIG. 8, it is shown that the rotational speed Ne of the engine 22 becomes the target rotational speed Netag based on the B position after the shift change at the time t3, but the rotational speed Ne of the engine 22 is the target rotational speed. The timing at which the number Netag is reached may vary from the timing when the predetermined time tref elapses.

  As described above, in the embodiment, when the shift position SP is changed from the D position to the B position or the S position or the shift position SP is downshifted in the S position while the accelerator is off, Only during the predetermined time tref, the input limit Win of the battery 50 used before the shift change is changed to a control input limit Winf that is set as a power value larger than this, so a shift such as a downshift is performed when the accelerator is off. The required torque Tr * as the braking force based on the change is prevented from being covered by the braking torque due to the motoring (engine braking) of the engine 22 and the braking torque due to the regenerative control of the motor MG2. Torque Tr * can be secured more easily.In addition, since the predetermined time tref is determined as a time during which the driver can experience the change in the braking force of the vehicle, the driving feeling associated with the shift change when the accelerator is off can be improved. Furthermore, if the shift position SP is changed from the D position to the B position or the S position or the shift position SP is downshifted in the S position while the accelerator is off. In addition, when it is estimated that the required torque Tr * is insufficient due to the input limit Win of the battery 50, the engine 22 is motored at a rotational speed that is lower by a predetermined rotational speed Nref than before the shortage is estimated. In addition, when the shift is changed thereafter, the engine speed Ne is increased at a rate of increase ΔN2 that is higher than the first rate ΔN1, which is a normal rate of increase when the accelerator is off. Sometimes the speed Ne of the engine 22 is lowered in advance, and the shift is changed afterwards. As the rotation of the engine 22 increases, the braking torque acting on the vehicle can be increased due to the inertia of the rotating system including the engine 22. As a result, the required torque Tr * can be more easily secured when the size of the input limit Win of the battery 50 is small.

  According to the hybrid vehicle 20 of the embodiment described above, the required torque Tr * required as a braking force when the accelerator is off is within the range of the input limit Win of the battery 50, and the motoring in a state where the fuel of the engine 22 is cut off. When the engine 22 and the motors MG1 and MG2 are controlled so as to travel by being covered by the braking torque generated by the motor MG2 and the braking torque on the power generation side of the motor MG2, the shift position SP is changed from the D position while the accelerator is off. When changing to B position or S position or downshifting at S position to increase the amount of braking force required when the accelerator is off, control as battery input limit Win than before changing the shift. Input limit Win for control with a larger absolute value To change a predetermined time tref in. Thereby, even if it is only the predetermined time tref, the degree to which the required torque Tr * as the braking force required based on the shift operation when the accelerator is off cannot be covered, that is, the required torque Tr * is further reduced. While ensuring, it can make the driving | operation feeling accompanying the shift operation at the time of an accelerator off favorable.

  Further, according to the hybrid vehicle 20 of the embodiment, when it is estimated that the required torque Tr * is not covered by the input limit Win of the battery 50 if the shift is changed while the accelerator is off, The engine 22 and the motors MG1 and MG2 are controlled so that the engine 22 is motored at a speed lower by a predetermined speed Nref than before the shortage estimation, and at the time of shift change, the target increase rate of the speed Ne of the engine 22 is increased. Since ΔNeup is set to a second rate ΔN2 that is higher than the first rate ΔN1 before the shift change, the engine speed Ne of the engine 22 is lowered in advance when the shortage is estimated, and the engine 22 increases when the shift is changed thereafter. Accordingly, the magnitude of the braking torque acting on the vehicle is increased by the inertia of the rotating system including the engine 22. Rukoto can. As a result, the required torque Tr * can be more easily secured when the size of the input limit Win of the battery 50 is small.

  In the hybrid vehicle 20 of the embodiment, when the shift position SP is not at the time of a shift change such as a change from the D position to the B position, or when a predetermined time tref has elapsed since the last shift change, the required torque Tr * The target rotational speed Nettag of the engine 22 is lowered by a predetermined rotational speed Nref, but it is not determined whether the engine 22 is in shortage. The process for lowering the target rotational speed Netag by the predetermined rotational speed Nref may not be performed.

  In the hybrid vehicle 20 according to the embodiment, when the shift position SP is changed from the D position to the B position, or when the predetermined time tref has not elapsed since the previous shift change, the engine 22 Although the target increase rate ΔNup of the control target rotational speed Ne * is set to the second rate ΔN2 that is larger than the normal first rate ΔN1, the target increase rate ΔNup is always set without setting the second rate ΔN2. It may be the first rate ΔN1. Even in this case, when the torque shortage is estimated, the target rotational speed Netag of the engine 22 is lowered by the predetermined rotational speed Nref, so that the power (torque due to the inertia of the rotational system of the engine 22 is extended for a longer time when the shift is changed thereafter. ) Can be used to apply a braking torque to the drive shaft 36.

  In the embodiment, the present invention is applied to the hybrid vehicle 20 including the planetary gear 30 in which the drive shaft 36 coupled to the drive wheels 38a and 38b, the crankshaft 26 of the engine 22 and the rotation shaft of the motor MG1 are connected to the ring gear, the carrier, and the sun gear. Although the invention has been described, the planetary gear 30 is not provided, and the engine that outputs the driving power, the first motor that can motor the engine, and the second motor that can input and output the driving power. The present invention may be applied to any type of hybrid vehicle as long as it is a hybrid vehicle including a motor.

  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 motor MG2 corresponds to the “second motor”, the battery 50 corresponds to the “battery”, The required torque Tr * set as the braking force when the accelerator is off is basically within the range of the input limit Win of the battery 50, and the drive shaft 36 is driven by the braking torque due to motoring of the engine 22 and the braking torque due to regenerative control of the motor MG2. When the shift position is changed such that the shift position SP is changed from the D position to the B position while the accelerator is off, the control input whose absolute value is larger than the input limit Win of the battery 50 for a predetermined time tref. The required torque Tr * is within the range of the limit Winf and the motoring of the engine 22 and the regeneration of the motor MG2 By setting the control input limit Winf for the battery 50 so as to act on the drive shaft 36, the target rotational speed Ne * of the engine 22, the fuel cut command, the torque commands Tm1 *, Tm2 * of the motors MG1, MG2 are set. The HVECU 70 for executing the accelerator off-time control routine of FIG. 2 for transmitting the set value to the engine ECU 24 and the motor ECU 40, the engine ECU 24 for stopping the fuel injection control and ignition control of the engine 22 in response to the fuel cut command, and the torque command Tm1 The motor ECU 40 that controls the motors MG1 and MG2 with * and Tm2 * corresponds to “control means”.

  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 electronic control unit for engine (engine ECU), 26 crankshaft, 30 planetary gear, 36 drive shaft, 37 differential gear, 38a, 38b drive wheel, 39a, 39b wheel, 40 electronic control unit for motor (Motor ECU), 41, 42 inverter, 43, 44 rotational position detection sensor, 50 battery, 52 electronic control unit for battery (battery ECU), 70 electronic control unit for hybrid (HVECU), 80 ignition switch, 81 shift lever, 82 Shift position sensor, 83 Accelerator pedal, 84 Accelerator pedal position sensor, 85 Brake pedal, 86 Brake pedal position sensor, 88 Vehicle speed sensor, MG1, MG 2 Motor.

Claims (3)

An engine that outputs power for traveling; a first motor that can motor the engine; a second motor that can input and output power for traveling; the first motor and the second motor; In a hybrid vehicle comprising a battery that exchanges power,
The required torque required as a braking force when the accelerator is off is within the range of the allowable charging power of the battery, by the torque due to motoring when the fuel of the engine is cut off and the torque on the power generation side of the second motor Control means for controlling the engine, the first motor and the second motor so as to be covered and traveled;
The control means changes the shift position when the shift position is changed from the first position to the second position larger than the first position when the accelerator is off while the accelerator is off. Sometimes it is a means for setting the charge allowable power of the battery to a power that is larger by a predetermined time than before the shift change,
A hybrid vehicle characterized by that. The hybrid vehicle according to claim 1,
If the shift position is changed from the first position to the second position while the accelerator is off, it is estimated that the required torque is not covered by the chargeable power of the battery. At the time of shortage estimation, the engine and the first motor are controlled so that the engine is motored at a rotational speed that is lower by a predetermined rotational speed than before the shortage estimation time.
Hybrid car. A hybrid vehicle according to claim 2,
The control means is means for controlling the engine and the first motor so that when the shift is changed, an increasing speed of the engine speed is higher than that before the shift change.
Hybrid car.

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