JP2014201105A - Hybrid automobile - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress a vehicle vibration possibly caused when a fuel injection to an engine is restarted in the state of the fuel injection to the engine being stopped, motoring the engine.SOLUTION: When a fuel injection is started to an engine that is under motoring at a speed equal to or higher than a threshold Nref in association with a fuel cut by a steep acceleration requirement based on a throttle position Acc, required-drive force Tr* is gradually increased by using a rate value Trt2 that is smaller than a normal rate value Trt1 used when operating the engine through a fuel injection thereto, after the required-drive force Tr* reaches or exceeds a threshold Tref (S200). This makes it possible to suppress a vehicle vibration possibly caused in association with a rapid change in the required-drive force Tr* when the fuel injection is restarted to the engine that has been fuel-cut and motoring.

Description

  The present invention relates to a hybrid vehicle. More specifically, the present invention has a planetary gear mechanism connected to an engine, a first motor, and a second motor, and the engine and the first motor are configured to travel with a requested driving force set based on an accelerator operation. The present invention relates to a hybrid vehicle that controls a motor and a second motor.

  Conventionally, this type of automobile is an automobile that outputs the power from the engine to the drive shaft via an automatic transmission having a torque converter. At the time of fuel injection return from the fuel cut operation of the engine, the engine speed and torque are reduced. There has been proposed one that retards the ignition timing based on the ratio of the rotation speeds of the converter (see, for example, Patent Document 1). In this automobile, such control suppresses an increase in the engine speed when the fuel cut is restored, thereby eliminating the uncomfortable feeling to the driver.

  Further, in a hybrid vehicle having an engine, a planetary gear mechanism connected to the first motor and the second motor, at the time of fuel injection return from the fuel cut operation of the engine, the rate of increase of the engine speed is increased during normal times. There has also been proposed one that controls the engine, the first motor, and the second motor so that the engine speed is increased by using a value smaller than the rate (see, for example, Patent Document 2). In this hybrid vehicle, such control suppresses a shock caused by a sudden change in the engine speed that may occur when the fuel cut is restored.

  Further, in an automobile that outputs the power from the engine to the axle side via a belt-type continuously variable transmission, the ignition timing increases as the intake air amount increases when the fuel injection returns from the fuel cut operation of the engine. There has been proposed one that corrects the ignition delay so as to retard (see, for example, Patent Document 3). In this automobile, such control avoids deterioration of drivability when returning from fuel injection.

JP 09-203367 A JP 2008-202533 A JP 2010-106676 A

  In a hybrid vehicle, when fuel injection to the engine is stopped, the engine is motored at a speed higher than the rotation speed corresponding to the traveling state such as the vehicle speed in order to output a large amount of power quickly from the engine for the subsequent accelerator operation. Ringing is also performed. In this way, when fuel injection is resumed when the engine is motored at a relatively high rotational speed, a relatively large driving force is output. Therefore, when the accelerator operation amount is large, the driving force changes rapidly. As a result, the vehicle may vibrate and drivability deteriorates.

  The main purpose of the hybrid vehicle of the present invention is to suppress vehicle vibration that may occur when fuel injection to the engine is resumed from a state where the fuel injection to the engine is stopped and the engine is motored.

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

The hybrid vehicle of the present invention
An engine, a first motor capable of generating electricity, a planetary gear mechanism in which three rotary elements are connected to an output shaft of the engine, a rotary shaft of the first motor, and a drive shaft connected to an axle; A second motor for inputting and outputting power; a battery capable of exchanging power with the first motor and the second motor; and the engine and the first motor so as to run with a required driving force set based on an accelerator operation. And a control means for controlling the second motor,
The control means controls the engine based on an accelerator operation during motoring of the engine to a rotational speed equal to or higher than a predetermined rotational speed by the first motor in a state where fuel injection to the engine is stopped. When the fuel injection is restarted and accelerated, the required driving force changes at a smaller change speed than when the engine is operated with fuel injection and accelerated based on the accelerator operation. Means for setting the required driving force;
It is characterized by that.

  In the hybrid vehicle of the present invention, the fuel injection to the engine is stopped and the engine is motored by the first motor so that the engine has a rotational speed equal to or higher than a predetermined rotational speed. When resuming fuel injection and accelerating, the required driving force changes at a smaller change rate than when accelerating based on accelerator operation while the engine is operating with fuel injection, that is, The required driving force is set so as to increase at a slower change rate (slow change) than the normal change rate. In this way, by changing the required driving force so as to increase slowly, it is possible to suppress the vibration of the vehicle that may occur due to a sudden change in the driving force. As a result, it is possible to improve drivability at the time of fuel injection return from the fuel cut.

  In such a hybrid vehicle of the present invention, the required drive force is slowly changed when the accelerator operation amount is greater than or equal to the predetermined operation amount, or when the change rate of the accelerator operation amount is greater than or equal to the predetermined change rate. Or you may. When the accelerator operation amount is relatively small below the predetermined operation amount or when the change rate of the accelerator operation amount is small below the predetermined change rate, the required driving force does not change suddenly. This is because it is considered that no vibration occurs in the vehicle.

  In the hybrid vehicle of the present invention, the required driving force is set so as to increase at a normal change speed until the required driving force reaches the predetermined driving force, and after the required driving force reaches the predetermined driving force or more, The required driving force may be set so as to increase at a change speed (slow change) slower than the normal change speed.

1 is a configuration diagram showing an outline of a configuration of a hybrid vehicle 20 as an embodiment of the present invention. 5 is a flowchart illustrating an example of a required driving force setting process routine executed by an HVECU 70. It is explanatory drawing which shows an example of the map for target drive force setting. Example of fuel cut execution flag Ffc, engine speed Ne, accelerator opening Acc, required driving force Tr *, and time variation of vehicle vibration when fuel injection is resumed in engine 22 that has been cut and fueled It is explanatory drawing which shows. FIG. 11 is a configuration diagram showing an outline of a configuration of a hybrid vehicle 120 according to a modification.

  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 FIG. 1, the hybrid vehicle 20 of the embodiment includes an engine 22 that outputs power using gasoline, light oil, or the like as a fuel, and an engine electronic control unit (hereinafter referred to as an engine ECU) 24 that drives and controls the engine 22. A planetary gear 30 in which a carrier is connected to the crankshaft 26 of the engine 22 and a ring gear is connected to a drive shaft 36 connected to the front wheels 38a and 38b via a differential gear 37, and is configured as, for example, a synchronous generator motor and rotates. A motor MG1 whose child is connected to the sun gear of the planetary gear 30, a motor MG2 configured as, for example, a synchronous generator motor and having a rotor connected to the drive shaft 36, and inverters 41 and 42 for driving the motors MG1 and MG2. Configured as, for example, a lithium ion secondary battery The battery 50 is connected to a power line to which the inverters 41 and 42 are connected (hereinafter referred to as a drive voltage system power line 54a) and a power line to which the battery 50 is connected (hereinafter referred to as a battery voltage system power line 54b). Boost converter that adjusts voltage VH of drive voltage system power line 54a in a range not less than voltage VL of battery voltage system power line 54b, and exchanges power between drive voltage system power line 54a and battery voltage system power line 54b 55, a motor electronic control unit (hereinafter referred to as a motor ECU) 40 that controls the drive of the motors MG1 and MG2 and controls the boost converter 55 by controlling the inverters 41 and 42, and a battery electronic that manages the battery 50 A control unit (hereinafter referred to as a battery ECU) 52 and the entire vehicle Gosuru hybrid electronic control unit (hereinafter, referred to HVECU) includes a 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 a rotational position detection sensor (not shown) that detects the rotational position of the rotor of the motors MG1 and MG2, and currents (not shown). The phase current applied to the motors MG1 and MG2 detected by the sensor, the drive voltage system voltage VH from the voltage sensor (not shown) attached to the drive voltage system power line 54a and the battery voltage system power line 54b (not shown) The battery voltage system voltage VL or the like from the voltage sensor is input via the input port. From the motor ECU 40, the switching control signal to the switching elements of the inverters 41 and 42 and the switching control signal to the switching element of the boost converter 55 are input. Etc. are output via the output 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 speeds Nm1 and Nm2 of the motors MG1 and MG2 based on the rotational positions θm1 and θm2 of the rotors of the motors MG1 and MG2 from the rotational position detection sensor.

  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, in order to manage the battery 50, the battery ECU 52 is a power storage that is a ratio of the capacity of the electric power that can be discharged from the battery 50 at that time based on the integrated value of the charge / discharge current Ib detected by the current sensor. The ratio SOC is calculated, and the input / output limits Win and Wout, which are the maximum allowable power that may charge / discharge the battery 50, are calculated based on the calculated storage ratio SOC and the battery temperature Tb. 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. 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.

  The hybrid vehicle 20 of the embodiment configured in this way calculates a required torque to be output to the drive shaft 36 based on the accelerator opening Acc and the vehicle speed V corresponding to the depression amount of the accelerator pedal 83 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 torque 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 power corresponding to the required power is output from the engine 22, and all of the power output from the engine 22 is transmitted to the planetary gear 30 and the motor MG1. The motor MG2 converts the torque of the motor MG1 and the motor MG2 so that the motor MG1 and the motor MG2 are driven and controlled, and the power suitable for the sum of the required power and the power required for charging and discharging the battery 50 is obtained. The operation of the engine 22 is controlled so as to be output from the engine 22, and all or a part of the power output from the engine 22 with charging / discharging of the battery 50 is converted by the planetary gear 30, the motor MG1, and the motor MG2. Accordingly, the required power is output to the drive shaft 36. Charge / discharge operation mode in which the motor MG1 and the motor MG2 are driven and controlled, and motor operation mode (EV travel 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 drive shaft 36. and so on. Both the torque conversion operation mode and the charge / discharge operation mode are modes in which the engine 22 and the motors MG1, 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 difference in the control, hereinafter, both are collectively referred to as an engine operation mode (HV travel mode).

  In the engine operation mode (HV traveling mode), the HVECU 70 basically outputs the requested drive 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. The force Tr * is set, and the set required driving force Tr * is multiplied by the rotation speed Nr of the drive shaft 36 (for example, the rotation speed obtained by multiplying the rotation speed Nm2 of the motor MG2 by the conversion coefficient or the vehicle speed V by the conversion coefficient). The travel power Pr * required for travel is calculated by multiplying the obtained number of revolutions), and the required charge / discharge power Pb * of the battery 50 obtained from the calculated travel power Pr * based on the storage ratio SOC of the battery 50 The vehicle required power Pv required for the vehicle is set by subtracting (a positive value when discharging from the battery 50), and the vehicle required power Pv is efficiently obtained. The target rotational speed Ne * and the target torque Te * of the engine 22 are set 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 be output from the engine 22. The engine speed Ne is within the range of the input / output limits Win and Wout set by the storage ratio SOC of the battery 50 and the temperature of the battery 50 as the maximum power that may charge and discharge the battery 50. A torque command Tm1 * as a torque to be output from the motor MG1 is set by rotation speed feedback control for achieving Ne *, and the drive shaft is driven via the planetary gear 30 when the motor MG1 is driven by the torque command Tm1 *. Torque command Tm2 of motor MG2 is obtained by subtracting the torque acting on 36 from the required driving force Tr * Set for the target rotational speed Ne * and the target torque Te * capital transmitted 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 * sets a target EGR rate Re * as a target value for the EGR rate Re based on the target rotational speed Ne * and the target torque Te *. The engine 22 is controlled so that the engine 22 is operated by the target rotational speed Ne * and the target torque Te * (specifically, the intake air amount control for controlling the opening degree of the throttle valve 124 and the fuel injection valve 126). Fuel injection control for controlling the fuel injection amount, ignition control for controlling the ignition timing of the spark plug 130, intake valve timing variable control for controlling the opening / closing timing of the intake valve 128, and the like. The motor ECU 40 that has received the torque commands Tm1 * and Tm2 * performs switching control of the switching elements of the inverters 41 and 42 so that the motors MG1 and MG2 are driven by the torque commands Tm1 * and Tm2 *.

  In the motor operation mode (EV traveling mode), the HVECU 70 sets the required driving force Tr *, the traveling power Pr *, and the vehicle required power Pv in the same manner as in the engine operating mode, and the torque command Tm1 * of the motor MG1 has a value of 0. Is set and a torque command Tm2 * of the motor MG2 is set and transmitted to the motor ECU 40 so that the required driving force Tr * is output to the drive shaft 36 within the range of the input / output limits Win and Wout of the battery 50. Then, the motor ECU 40 that receives the torque commands Tm1 * and Tm2 * performs switching control of the switching elements of the inverters 41 and 42 so that the motors MG1 and MG2 are driven by the torque commands Tm1 * and Tm2 *.

  Next, the required driving force Tr * at the time of the return of the fuel injection to the engine 22 that is motored by the operation of the hybrid vehicle 20 of the embodiment configured as described above, in particular, the fuel cut in the engine operation mode (HV travel mode). The operation when setting is described. FIG. 2 is a flowchart illustrating an example of a required driving force setting process routine executed by the HVECU 70. This routine is repeatedly executed at predetermined time intervals (for example, every several msec) while traveling in the engine operation mode (HV travel mode).

  When the requested driving force setting process routine is executed, the HVECU 70 first requests the accelerator opening Acc from the accelerator pedal 83, the vehicle speed V from the vehicle speed sensor 88, the rotational speed Ne of the engine 22, the fuel cut execution flag Ffc, and the like. A process of inputting data necessary for setting the driving force Tr * is executed (step S100). Here, the rotation speed Ne of the engine 22 is calculated based on a signal from a crank position sensor (not shown) and is input from the engine ECU 24 by communication. As the fuel cut execution flag Ffc, the one set by the engine ECU 24 is inputted by communication. The fuel cut execution flag Ffc is set to a value of 1 when fuel cut to the engine 22 is executed by a flag setting routine (not shown), and is set to 0 when fuel injection to the engine 22 is being performed. Is set.

  When the data is input in this way, the target driving force Ttag as a final target value of the driving force requested by the driver to the driving shaft 36 is set based on the input accelerator opening Acc and the vehicle speed V (step S110). In the embodiment, the target driving force Trtag is set in advance in a ROM (not shown) as a target driving force setting map by predetermining the relationship among the accelerator opening Acc, the vehicle speed V, and the target driving force Trtag. When the vehicle speed V is given, it is set by deriving the corresponding target driving force Ttag from the map. An example of the target driving force setting map is shown in FIG.

  Subsequently, the value of the control condition flag Fc is checked (step S120). Although the control condition flag Fc will be described later in detail, the required driving force setting process routine assumes a predetermined time value of 1 when a certain condition is satisfied upon return from the fuel cut, and otherwise. The value is 0. Therefore, the value is usually 0.

  When the control condition flag Fc has a value of 0, whether or not the fuel injection to the engine 22 that has been fuel cut is restored (step S130), and whether or not the rotational speed Ne of the engine 22 is greater than or equal to a threshold Nref ( In step S140, it is determined whether or not the driver is making a predetermined acceleration request that is predetermined as a relatively large acceleration request (step S150). In this embodiment, it is determined whether or not it is the time when the fuel injection to the engine 22 that has cut the fuel is restored. In this embodiment, the fuel cut execution flag Ffc that was input when this routine was executed last time is 1 and this routine is executed this time. When the fuel cut execution flag Ffc input at the time of execution is 0, that is, when the fuel cut execution flag Ffc changes from the value 1 to the value 0, it can be determined that the fuel injection is being returned. The threshold value Nref is set as a rotational speed at which a relatively large power can be output from the engine 22 when the fuel injection to the engine 22 that has been cut off is restored. For example, 2000 rpm or 2500 rpm is set. Can be used. The predetermined acceleration request may be determined when the accelerator opening degree Acc is greater than or equal to a relatively large threshold (for example, 80% or 90%), or when the time change rate of the accelerator opening degree Acc is greater than or equal to a relatively large threshold value. it can.

  When it is not at the time of return of fuel injection to the engine 22 that is cutting fuel, when the rotational speed Ne of the engine 22 is less than the threshold value Nref, or when the driver's acceleration request is not the predetermined acceleration request, The required driving force Tr * (hereinafter referred to as the previous required driving force Tr *) set when the routine is executed is compared with the target driving force Trtag (step S220), and the target driving force Trtag is the previous required driving force. If it is equal to or greater than Tr *, the smaller of the previous required drive recording Tr * plus the normal rate value Trt1 and the target drive force Trtag is set as the required drive force Tr * (step S230). When the target driving force Trtag is less than the previous requested driving force Tr *, the rate value Trt1 is subtracted from the previous requested driving record Tr *. Set the larger one of the target driving force Trtag as required driving force Tr * (step S240), and terminates this routine. Here, the rate value Trt1 is the operation control of the engine 22 even if the required driving force Tr * is changed every time this routine is executed when fuel is injected into the engine 22 and the engine 22 is normally operated. Is the amount of change in driving force that can increase or decrease the required driving force Tr * without failing, and can be determined by experiments or the like.

  In step S130 to S150, when the fuel injection to the engine 22 that has been fuel cut is restored, it is determined that the rotational speed Ne of the engine 22 is greater than or equal to the threshold value Nref, and the driver's acceleration request is a predetermined acceleration request If so, the acceleration request counter C is cleared to 0 and a value 1 is set to the control condition flag Fc (step S160). When the value 1 is set in the control condition flag Fc, a negative determination is made in step S120, and the process proceeds to step S170 without performing the processes in steps S130 to S160.

  When the acceleration request counter C is cleared to 0 and the control condition flag Fc is set to 1 in step S160, or when it is determined in step S120 that the control condition flag Fc is 1, the acceleration request count C is set. While incrementing by 1 (step S170), it is determined whether or not the acceleration request counter C is less than the threshold value Cref (step S180). Here, it is considered that the threshold value Cref needs to suppress the vibration of the vehicle caused by the sudden change in the required driving force Tr * after the fuel injection to the engine 22 that has been motored with the fuel cut is restarted. This is used to determine whether or not an elapsed time (for example, 2 seconds or 3 seconds) has elapsed until the timing, and is determined by an activation interval time of this routine.

  If it is determined in step S180 that the acceleration request counter C is less than the threshold value Cref, it is determined whether or not the previous required driving force Tr * is greater than or equal to the threshold value Tref (step S190). If less than Tref, the smaller of the previous requested driving force Tr * plus the normal rate value Trt1 and the target driving force Trtag is set as the requested driving force Tr * (step S230). When the previous requested driving force Tr * is equal to or greater than the threshold value Tref, the smaller one of the target driving force Trtag and the value obtained by adding the rate value Trt2 smaller than the normal rate value Trt1 to the previous requested driving record Tr * is requested. The driving force Tr * is set (step S200), and this routine is terminated. Here, the threshold value Tref is a driving force that causes the vehicle to vibrate when fuel injection is restored to the engine 22 that has been cut off and motored, thereby causing the driver to feel uncomfortable. Can do. In the above-described processing, when a large target driving force Ttag is set, the required driving force Tr is used by using the normal rate value Trt1 every time this routine is executed until the required driving force Tr * reaches the threshold value Tref or more. After increasing * and the required driving force Tr * reaches or exceeds the threshold value Tref, every time this routine is executed, a process of increasing the required driving force Tr * using a rate value Trt2 smaller than the normal rate value Trt1; Become. Therefore, the required driving force Tr * increases with a normal increase until the required driving force Tr * exceeds the threshold value Tref, and after the required driving force Tr * reaches the threshold value Tref or higher, the required driving force Tr * increases slowly. The driving force Tr * will increase. By setting the required driving force Tr * in this way, the vibration of the vehicle that may occur due to a sudden change in the required driving force Tr * when the fuel injection to the engine 22 that has been cut and fueled is restored. be able to.

  On the other hand, if it is determined in step S180 that the acceleration request counter C is greater than or equal to the threshold value Cref, the control condition flag Fc is set to a value 0 (step S210), and the previous required driving force Tr * is set to the normal rate value Trt1. Is set as the required driving force Tr * (step S230), and this routine is terminated.

  FIG. 4 shows the fuel cut execution flag Ffc, the engine speed Ne, the accelerator opening Acc, the required driving force Tr *, and the vehicle vibration when the fuel injection is resumed in the engine 22 that has been cut and fueled. It is explanatory drawing which shows an example of a time change. In the figure, in the required driving force Tr * and vehicle vibration, a solid line indicates an example, and a broken line indicates a case where a normal rate value Trt1 is always used as a comparative example. By increasing the accelerator opening Acc, fuel injection to the engine 22 is resumed at time T1, and the fuel cut execution flag Ffc is set from the value 1 to the value 0. As the accelerator opening Acc increases rapidly, the target driving force Ttag is set, and the required driving force Tr * increases toward the target driving force Ttag by the normal rate value Trt1. In the embodiment, after the time T2 when the required driving force Tr * reaches the threshold value Tref, the required driving force Tr * increases toward the target driving force Ttag by a rate value Trt2 that is smaller than the normal rate value Trt1. Compared to the slow change. Since the required driving force Tr * changes suddenly when the fuel injection to the engine 22 is resumed, the vehicle is vibrated. In the embodiment, the required driving force Tr * after the time T2 when the required driving force Tr * reaches the threshold value Tref. By slowly changing, vibration is suppressed as compared with the comparative example (broken line).

  According to the hybrid vehicle 20 of the embodiment described above, when fuel injection is resumed in the engine 22 that is motored at a rotational speed equal to or higher than the threshold Nref with a fuel cut due to a rapid acceleration request based on the accelerator opening Acc. After the required driving force Tr * reaches the threshold value Tref or more, the required driving force Tr * is requested by a rate value Trt2 smaller than the normal rate value Trt1 used when the engine 22 is normally operated by performing fuel injection to the engine 22. By gently changing the driving force Tr *, it is possible to suppress the vibration of the vehicle that may occur due to a sudden change in the required driving force Tr * when the fuel injection to the engine 22 that has been cut and fueled is restored. . As a result, it is possible to improve drivability at the time of fuel injection return from the fuel cut.

  In the hybrid vehicle 20 of the embodiment, when the fuel injection is resumed by the rapid acceleration request based on the accelerator opening Acc and the fuel injection is resumed in the engine 22 that is motored at the rotation speed equal to or higher than the threshold Nref, the required driving force Tr The required driving force Tr * is changed by the normal rate value Trt1 until * reaches the threshold value Tref or higher, and the required driving force Tr * is requested by the rate value Trt2 smaller than the normal rate value Trt1 after the required driving force Tr * reaches the threshold value Tref or higher. Although the driving force Tr * is gradually changed, the required driving force Tr * may be gradually changed by the rate value Trt2 even when the required driving force Tr * reaches the threshold value Tref or more.

  In the hybrid vehicle 20 of the embodiment, the power from the motor MG2 is output to the drive shaft 36 connected to the drive wheels 38a and 38b. However, as illustrated in the hybrid vehicle 120 of the modification of FIG. The power from MG2 may be output to an axle (an axle connected to wheels 39a and 39b in FIG. 5) different from an axle to which drive shaft 36 is connected (an axle to which drive wheels 38a and 38b are connected). .

  The correspondence between the main elements of the embodiment and the main elements of the invention described in the column of means for solving the problems will be described. In the embodiment, the engine 22 corresponds to the “engine”, the motor MG1 corresponds to the “first motor”, the planetary gear 30 corresponds to the “planetary gear mechanism”, the motor MG2 corresponds to the “second motor”, The battery 50 corresponds to a “battery” and executes the required driving force setting process routine of FIG. 2 and at the same time the target rotational speed Ne * and target torque Te * of the engine 22 based on the required driving force Tr * set by this routine. , HVECU 70 for setting torque commands Tm1 *, Tm2 * of motors MG1, MG2, engine ECU 24 for controlling the operation of engine 22 based on target rotational speed Ne * and target torque Te * from HVECU 70, and torque command from HVECU 70 The motor ECU 40 that drives and controls the motors MG1 and MG2 based on Tm1 * and Tm2 * It corresponds to the stage. "

  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, 120 Hybrid vehicle, 22 engine, 24 engine electronic control unit (engine ECU), 26 crankshaft, 30 planetary gear, 36 drive shaft, 37 differential gear, 38a, 38b drive wheel, 39a, 39b wheel, 40 motor electronics Control unit (motor ECU), 41, 42 inverter, 50 battery, 70 electronic control unit for hybrid, 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, MG2 motor.

Claims (1)

An engine, a first motor capable of generating electricity, a planetary gear mechanism in which three rotary elements are connected to an output shaft of the engine, a rotary shaft of the first motor, and a drive shaft connected to an axle; A second motor for inputting and outputting power; a battery capable of exchanging power with the first motor and the second motor; and the engine and the first motor so as to run with a required driving force set based on an accelerator operation. And a control means for controlling the second motor,
The control means controls the engine based on an accelerator operation during motoring of the engine to a rotational speed equal to or higher than a predetermined rotational speed by the first motor in a state where fuel injection to the engine is stopped. When the fuel injection is restarted and accelerated, the required driving force changes at a smaller change speed than when the engine is operated with fuel injection and accelerated based on the accelerator operation. Means for setting the required driving force;
A hybrid vehicle characterized by that.

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