JP5751185B2 - Hybrid car - Google Patents

Description

  The present invention relates to a hybrid vehicle, and more specifically, an engine in which an exhaust purification device having a catalyst for purifying exhaust is attached to an exhaust system, a first motor capable of motoring the engine, and output of traveling power The present invention relates to a hybrid vehicle including a possible second motor.

  Conventionally, as this type of technology, when the fuel supply to the engine mounted on the vehicle and having the exhaust purification catalyst in the exhaust passage is stopped according to the establishment of a predetermined fuel supply stop condition, the temperature of the exhaust purification catalyst is predetermined. Proposed is a prohibition condition that the value α is equal to or greater than that and the vehicle traveling speed is equal to or greater than a predetermined value β, and the fuel supply stop is prohibited according to the establishment of the prohibition condition (for example, Patent Documents). 1). In the fuel supply control to the engine, the above-described prohibition condition is provided to suppress the exhaust sulfur odor and the deterioration of the exhaust purification catalyst due to heat.

  Further, in a hybrid vehicle including an engine having an exhaust purification device attached to an exhaust system and a traveling motor, it is determined that catalyst deterioration is promoted because the temperature of the catalyst of the exhaust purification device is high. When the target engine speed decreases due to accelerator off or the like, and the difference between the engine speed and the target engine speed is greater than a threshold value, the vehicle speed is greater than the threshold value set to a larger value as the catalyst temperature increases. It has been proposed to control the engine speed so as to reach the target speed while continuing the engine explosion combustion, and to execute the fuel cut of the engine when the vehicle speed is smaller than the threshold value (see, for example, Patent Document 2). In this hybrid vehicle, when the catalyst temperature is high and the deterioration of the catalyst is promoted, the catalyst deterioration suppressing control for continuing the explosion combustion of the engine is continued as long as possible to suppress the catalyst deterioration.

Japanese Patent Laying-Open No. 2005-147082 JP 2007-192113 A

  In a hybrid vehicle including an engine, a first motor capable of motoring the engine, and a second motor capable of outputting driving power, when the driver turns off the accelerator, the engine rotates without requiring an output to the engine. May hold a number. If the driver turns off the accelerator while traveling at a relatively high vehicle speed, there is no output request to the engine, but the next time the driver depresses the accelerator, the vehicle speed The engine speed is maintained accordingly. At this time, normally, in order to maintain good fuel efficiency, the engine speed is maintained by motoring by the first motor while the fuel supply to the engine is stopped. On the other hand, when the temperature of the catalyst of the exhaust purification system attached to the engine exhaust system becomes higher than the normal range, such as when the engine is operated at a high load, the catalyst has a lean atmosphere (air (oxygen)) at high temperatures. In order to prevent the deterioration of the catalyst caused by being exposed to the atmosphere), the catalyst deterioration suppression control is performed to prohibit engine fuel cut and continue the engine explosion combustion. Therefore, if the engine speed is maintained by turning off the accelerator at a relatively high vehicle speed and the catalyst deterioration suppression control by the high catalyst temperature is required at the same time, the engine speed is maintained by the engine explosion caused by the fuel supply. It will be performed with combustion, and the fuel efficiency will deteriorate. On the other hand, if the engine speed is not maintained, deterioration of fuel consumption can be suppressed by stopping the engine, but the next time the driver steps on the accelerator, it takes time to start the engine. In addition, power cannot be output from the engine quickly, and the driving feeling is deteriorated.

  The main object of the hybrid vehicle of the present invention is to achieve a certain degree of coexistence of suppression of deterioration of fuel consumption and suppression of deterioration of driving feeling while suppressing deterioration of the catalyst of the exhaust purification device.

  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 in which an exhaust gas purification device having a catalyst for purifying exhaust gas is attached to an exhaust system, a first motor capable of motoring the engine, a second motor capable of outputting driving power, and the first A battery capable of exchanging electric power with the motor and the second motor, and when the vehicle speed is less than the determination vehicle speed when there is no output request to the engine, the engine speed is set to 0 and the operation of the engine is stopped. The engine, the first motor, and the second motor are controlled, and the engine and the first motor are maintained such that the rotation of the engine is maintained when the vehicle speed is equal to or higher than the determination vehicle speed when there is no output request to the engine. In a hybrid vehicle comprising a motor and control means for controlling the second motor,
The control means is means for using a larger value as the determination vehicle speed as the temperature of the catalyst is higher.
It is characterized by that.

  In the hybrid vehicle of the present invention, the higher the temperature of the catalyst of the exhaust purification device attached to the exhaust system of the engine, the larger the value is set as the determination vehicle speed, and when the vehicle speed is less than the determination vehicle speed when there is no output request to the engine. The engine, the first motor, and the second motor are controlled so as to stop the operation of the engine by setting the engine speed to 0, and the engine rotation is maintained when the vehicle speed is equal to or higher than the determination vehicle speed when there is no output request to the engine. The engine, the first motor, and the second motor are controlled as described above. That is, the determination vehicle speed is increased as the catalyst temperature is higher, and the frequency at which the rotation of the engine is maintained when there is no output request to the engine is decreased. As a result, when the temperature of the catalyst is high, the frequency of maintaining the rotation of the engine with the explosion combustion of the engine can be reduced, and deterioration of the fuel consumption can be suppressed to some extent while suppressing deterioration of the catalyst. Deterioration of driving feeling can be suppressed to some extent. Here, as the relationship between the catalyst temperature and the determination vehicle speed, the determination vehicle speed is determined in advance when the catalyst temperature is lower than a predetermined temperature that is determined in the vicinity of the lower limit of the temperature range in which deterioration of the catalyst is promoted. The predetermined vehicle speed may be constant, and when the catalyst temperature is equal to or higher than the predetermined temperature, the determination vehicle speed may increase as the catalyst temperature increases.

  In such a hybrid vehicle of the present invention, the control means is means for controlling the first motor and the second motor within a range of output restriction based on the state of the battery, and further, an output request to the engine. When an output request to the engine is made from a state where there is no power, the output limit is limited by a correction value that increases as the determination vehicle speed increases and / or as the amount of power stored in the battery increases, until a predetermined time elapses. It can also be characterized by being a means to be used after correction. In this way, when the accelerator is depressed by the driver while the engine is stopped because the vehicle speed is less than the judgment vehicle speed, it takes time to output power from the engine because it is necessary to start the engine. Even so, the power output from the second motor can be increased, and the deterioration of driving feeling can be suppressed to some extent. In particular, since the output limit is corrected using a correction value that increases as the determination vehicle speed increases or the amount of power stored in the battery increases, the correction value can be made more appropriate.

  The hybrid vehicle of the present invention may include a planetary gear mechanism in which three rotating elements are connected to three axes of an axle, an engine output shaft, and a first motor rotating shaft.

1 is a configuration diagram showing an outline of a configuration of a hybrid vehicle 20 according to an embodiment of the present invention. 2 is a configuration diagram showing an outline of the configuration of an engine 22. FIG. 5 is a flowchart showing an example of a drive 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 a mode that the target rotational speed Ne * and the target torque Te * are set as an example of a fuel consumption optimal operation line. It is explanatory drawing which shows an example of the map for determination vehicle speed setting. It is explanatory drawing which shows an example of an alignment chart when the engine 22 is stopped and when the rotation speed Ne of the engine 22 is held at a predetermined rotation speed Nset. It is explanatory drawing which shows an example of the map for an output correction value setting. FIG. 10 is a configuration diagram illustrating 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 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 in which a carrier is connected to a crankshaft 26 as an output shaft 22 and a ring gear is connected to a drive shaft 32 connected to drive wheels 63a and 63b via a differential gear 62; Then, the motor MG1 whose rotor is connected to the sun gear of the planetary gear 30, a motor MG2 configured as, for example, a synchronous generator motor and whose rotor is connected to the drive shaft 32, and an inverter 41 for driving the motors MG1 and MG2 , 42 and inverters 41, 42 A motor electronic control unit (hereinafter referred to as a motor ECU) 40 for driving and controlling the motors MG1 and MG2 by switching control of the switching elements, a battery 50 configured as, for example, a lithium ion secondary battery, and inverters 41 and 42 Are connected to a power line (hereinafter referred to as a high voltage system power line) 54a and a power line (hereinafter referred to as a battery voltage system power line) 54b to which the battery 50 is connected. Boost converter 55 that exchanges power with voltage system power line 54b, battery electronic control unit (hereinafter referred to as battery ECU) 52 that manages battery 50, and hybrid electronic that controls the entire drive system of the vehicle A control unit (hereinafter referred to as HVECU) 70 That.

  As shown in FIG. 2, the engine 22 sucks air purified by the air cleaner 122 through the throttle valve 124 and injects gasoline from the fuel injection valve 126 to mix the sucked air and gasoline. The air-fuel mixture is sucked into the fuel chamber via the intake valve 128 and is explosively burned by an electric spark from the spark plug 130. The reciprocating motion of the piston 132 pushed down by the energy is converted into the rotational motion of the crankshaft 26. Exhaust gas from the engine 22 is sent to the outside air through a purification device 134 having a purification catalyst (three-way catalyst) 134a that purifies harmful components such as carbon monoxide (CO), hydrocarbons (HC), and nitrogen oxides (NOx). Discharged.

  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 detects signals from various sensors that detect the state of the engine 22, for example, the crank position θcr from the crank position sensor 140 that detects the rotational position of the crankshaft 26 and the coolant temperature of the engine 22. The cam position for detecting the coolant temperature Tw from the water temperature sensor 142, the in-cylinder pressure Pin from the pressure sensor attached to the combustion chamber, and the rotational position of the intake valve 128 for intake and exhaust to the combustion chamber and the camshaft for opening and closing the exhaust valve Cam position θca from sensor 144, throttle opening TH from throttle valve position sensor 146 for detecting the position of throttle valve 124, intake air amount Qa from air flow meter 148 attached to the intake pipe, and also attached to the intake pipe Temperature Intake air temperature Ta from the sensor 149, catalyst temperature Tc from the temperature sensor 134b for detecting the temperature of the purification catalyst 134a, air-fuel ratio AF from the air-fuel ratio sensor 135a attached to the exhaust system, and oxygen sensor also attached to the exhaust system An oxygen signal O2 and the like from 135b is input via the input port. The engine ECU 24 also integrates various control signals for driving the engine 22, such as a drive signal to the fuel injection valve 126, a drive signal to the throttle motor 136 that adjusts the position of the throttle valve 124, and an igniter. The control signal to the ignition coil 138 and the control signal to the variable valve timing mechanism 150 that can change the opening / closing timing of the intake valve 128 are output via the output port. The engine ECU 24 communicates 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 operating state of the engine 22 as necessary. The engine ECU 24 calculates the rotational speed of the crankshaft 26, that is, the rotational speed Ne of the engine 22 based on the crank position θcr from the crank position sensor 140. Further, the engine ECU 24 is exposed to the lean atmosphere when the catalyst temperature Tc from the temperature sensor 134b is lower than a deterioration promoting lower limit temperature that is predetermined as a lower limit temperature at which the deterioration is accelerated when the purification catalyst 143a is exposed to the lean atmosphere. However, it is determined that the deterioration of the purification catalyst 134a is not accelerated, and the value 0 is set in the catalyst deterioration suppression flag Fc. When the catalyst temperature Tc is equal to or higher than the deterioration promotion lower limit temperature, the deterioration of the purification catalyst 134a may occur when exposed to a lean atmosphere. A value 1 is set to the catalyst deterioration suppression flag Fc because it is determined to be promoted. When the value 1 is set in the catalyst deterioration suppression flag Fc1, the fuel injection is performed so that the intake air amount of the engine 22 becomes stoichiometric so that the purification catalyst 143a is not exposed to the lean atmosphere. The catalyst deterioration suppression control that continues is executed. The catalyst deterioration suppression flag Fc is not limited to the one set using the temperature sensor 134b that directly detects the catalyst temperature Tc, but is set based on the estimated temperature estimated according to the load state of the engine 22. Also good.

  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). A phase current applied to the motors MG1 and MG2 detected by the sensor is input via the input port, and a switching control signal to a switching element (not shown) of the inverters 41 and 42 is output from the motor ECU 40. It is output via. 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 a shift position SP from the shift position sensor 82 that detects the operation position of the shift lever 81, an accelerator opening Acc from the accelerator pedal position sensor 84 that detects the depression amount of the accelerator pedal 83, and a depression amount of the brake pedal 85. The brake pedal position BP from the brake pedal position sensor 86 for detecting the vehicle speed, 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.

  In the hybrid vehicle 20 of the embodiment thus configured, the required torque Tr * to be output to the drive shaft 32 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 32. 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 motor MG1 and the motor MG2 and output to the drive shaft 32, and the sum of the required power and the power required for charging and discharging the battery 50 are 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 32 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 32. The torque conversion operation mode and the charge / discharge operation mode are modes for controlling the engine 22, the motor MG1, and the motor MG2 so that the required power is output to the drive shaft 32 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 32 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 32 (for example, the rotational speed Nm2 of the motor MG2 or the rotational speed obtained by multiplying the vehicle speed V by a conversion factor). The charge / discharge required power Pb * (a 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 subtracted and a loss (loss) is added. To set the required power Pe * as the power to be output from the engine 22. 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 32 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 * performs intake air amount control and fuel injection control of the engine 22 so that the engine 22 is efficiently operated by the target rotational speed Ne * and the target torque Te *. The motor ECU 40 that performs ignition control and 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 *. .

  In the motor operation mode, the HVECU 70 sets a required torque Tr * to be output to the drive shaft 32 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 32 within the range of the input / output limits Win, Wout. 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 operation of the hybrid vehicle 20 of the embodiment configured as described above, particularly the operation while the purification catalyst 134a is traveling at a relatively high speed in a relatively high temperature state will be described. FIG. 3 is a flowchart showing an example of a drive control routine executed by the CPU 72 of the HVECU 70. This routine is repeatedly executed every predetermined time (for example, every several msec).

  When the drive control routine is executed, first, the CPU 72 of the HVECU 70 first determines the accelerator opening Acc from the accelerator pedal position sensor 84, the vehicle speed V from the vehicle speed sensor 88, the rotational speed Ne of the engine 22, and the rotational speeds of the motors MG1 and MG2. Nm1, Nm2, input / output limits Win and Wout of the battery 50, catalyst temperature Tc, catalyst deterioration suppression flag Fc, and other data necessary for control are executed (step S100). Here, the rotational speed Ne of the engine 22 is calculated based on a signal from the crank position sensor 140 and is input from the engine ECU 24 by communication. Further, the rotational speeds Nm1 and Nm2 of the motors MG1 and MG2 are input from the motor ECU 40 by communication from those calculated based on the rotational positions of the rotors of the motors MG1 and MG2 detected by the rotational position detection sensors 43 and 44. It was supposed to be. Further, 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 remaining capacity (SOC) of the battery 50 and input from the battery ECU 52 by communication. The catalyst temperature Tc detected by the temperature sensor 134b is input from the engine ECU 24 by communication. The catalyst deterioration suppression flag Fc set by the catalyst temperature Tc is input from the engine ECU 24 by communication.

  When the data is input in this way, the required torque Tr * to be output to the drive shaft 32 connected to the drive wheels 63a and 63b as the torque required for the vehicle based on the input accelerator opening Acc and the vehicle speed V, and the engine 22 The required required power Pe * is set (step S110). In the embodiment, the required torque Tr * is determined in advance by storing the relationship between the accelerator opening Acc, the vehicle speed V, and the required torque Tr * in the ROM 74 as a required torque setting map, and the accelerator opening Acc, the vehicle speed V, , The corresponding required torque Tr * is derived and set from the stored map. FIG. 4 shows an example of the required torque setting map. The required power Pe * can be calculated as the sum of the set required torque Tr * multiplied by the rotational speed Nr of the drive shaft 32 and the charge / discharge required power Pb * required by the battery 50 and the loss Loss. The rotational speed Nr of the drive shaft 32 can be obtained by multiplying the vehicle speed V by a conversion coefficient k (Nr = k · V) or can be obtained as the rotational speed Nm2 of the motor MG2.

  Subsequently, it is determined whether or not the engine 22 is in operation (step S120). When the engine 22 is in operation, it is determined whether or not the set required power Pe * is less than a threshold value Pstop for stopping the operation of the engine 22. Determination is made (step S130). Here, as the threshold value Pstop, a value in the vicinity of the lower limit value of the power region in which the engine 22 can be operated relatively efficiently can be used.

  When the required power Pe * is equal to or greater than the threshold value Pstop, it is determined that an output request to the engine 22 is made, and an operation line as a relationship between the rotational speed Ne of the engine 22 and the torque Te that optimizes fuel efficiency is determined in advance. Based on the optimum fuel efficiency operation line and the set required power Pe *, a target rotational speed Ne * and a target torque Te * are set as operating points at which the engine 22 should be operated (step S260), and the set target rotational speed Ne is set. * And target torque Te * are transmitted to engine ECU 24 (step S270). FIG. 5 shows a state where the target rotational speed Ne * and the target torque Te * are set as an example of the fuel efficiency optimum operation line. As shown in the figure, the target rotational speed Ne * and the target torque Te * can be obtained from the intersection of the fuel efficiency optimal operation line and a curve with a constant required power Pe * (Ne * × Te *). The engine ECU 24 that has received the target rotational speed Ne * and the target torque Te * controls the intake air amount in the engine 22 so that the engine 22 is operated at the operating point indicated by the target rotational speed Ne * and the target torque Te *. Controls such as fuel injection control and ignition control.

  Next, using the target rotational speed Ne * of the engine 22, the rotational speed Nm2 of the motor MG2, and the gear ratio ρ of the planetary gear 30, the target rotational speed Nm1 * of the motor MG1 is calculated and calculated by the following equation (1). Based on the rotational speed Nm1 * and the input rotational speed Nm1 of the motor MG1, a torque command Tm1 * to be output from the motor MG1 is calculated by equation (2) (step S280). Here, Expression (1) is a relational expression regarding the mechanical rotational speed of the rotating element of the planetary gear 30, and Expression (2) is a relational expression in feedback control for rotating the motor MG1 at the target rotational speed Nm1 *. It is. In Expression (2), “k1” in the second term on the right side is the gain of the proportional term, and “k2” in the third term on the right side is the gain of the integral term. Note that the first term on the right side of the equation (2) is a torque as a reaction force against the torque acting via the planetary gear 30 when the target torque Te * is output from the engine 22.

Nm1 * = Ne * ・ (1 + ρ) / ρ-Nm2 / ρ (1)
Tm1 * = ρ ・ Te * / (1 + ρ) + k1 (Nm1 * -Nm1) + k2∫ (Nm1 * -Nm1) dt (2)

  Then, by adding the torque command Tm1 * set to the required torque Tr * divided by the gear ratio ρ of the planetary gear 30, a temporary torque Tm2tmp, which is a temporary value of the torque to be output from the motor MG2, is given by the following equation (3). The deviation from the power consumption (generated power) of the motor MG1 obtained by calculating (step S290) and multiplying the input / output limits Win and Wout of the battery 50 by the torque command Tm1 * and the current rotational speed Nm1 of the motor MG1 is calculated as the motor MG2. The torque limits Tmin and Tmax as upper and lower limits of the torque that may be output from the motor MG2 by dividing by the rotation speed Nm2 are calculated by the following equations (4) and (5) (step S300), and the set temporary Torque Tm2tmp is limited by torque limits Tmin and Tmax according to equation (6), and torque command T of motor MG2 is set. Set 2 * (step S310), the torque command Tm1 * set, by sending Tm2 * to the motor ECU 40 (step S320), and terminates the drive control 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 *. .

Tm2tmp = Tr * + Tm1tmp / ρ (3)
Tmin = (Win-Tm1 * ・ Nm1) / Nm2 (4)
Tmax = (Wout-Tm1 * ・ Nm1) / Nm2 (5)
Tm2 * = max (min (Tm2tmp, Tmax), Tmin) (6)

  When the output request to the engine 22 is made, the engine 22 is efficiently operated within the range of the input / output limits Win and Wout of the battery 50 by repeating the above-described steps S260 to S320, and the drive shaft 32 is requested. The vehicle can travel by outputting torque Tr *.

  When it is determined in step S130 that the required power Pe * is less than the threshold value Pstop, it is determined that there is no output request to the engine 22, and the determination vehicle speed Vaj is set so as to increase as the catalyst temperature Tc increases (step S140). ), The vehicle speed V is compared with the set vehicle speed Vaj (step S150). In the embodiment, the determination vehicle speed Vaj is stored in the ROM 74 as a determination vehicle speed setting map by predetermining the relationship between the catalyst temperature Tc and the determination vehicle speed Vaj, and when the catalyst temperature Tc is given, the corresponding determination is made from the stored map. The vehicle speed Vaj is derived and set. FIG. 6 shows an example of the determination vehicle speed setting map. In the example of FIG. 6, when the catalyst temperature Tc is lower than a predetermined temperature Tset that is set slightly lower than the temperature at which deterioration is accelerated, a predetermined vehicle speed Vset that is set in advance is set as the determination vehicle speed Vaj, and the catalyst temperature Tc is When the temperature is equal to or higher than the predetermined temperature Tset, the higher the catalyst temperature Tc, the higher the vehicle speed is set as the determination vehicle speed Vaj. In the example of FIG. 6, the predetermined vehicle speed Vset is set as the determination vehicle speed Vaj when the catalyst temperature Tc is lower than the predetermined temperature Tset. However, the catalyst temperature Tc is also set when the catalyst temperature Tc is lower than the predetermined temperature Tset. The higher the vehicle speed, the higher the vehicle speed may be set as the determination vehicle speed Vaj.

  When the vehicle speed V is less than the determination vehicle speed Vaj, the operation of the engine 22 is stopped (step S160), a value 0 is set to the torque command Tm1 * of the motor MG1, and the torque command Tm1 * of this value 0 is used to perform step S290. To S310, the torque command Tm2 * of the motor MG2 is set, the set torque commands Tm1 * and Tm2 * are transmitted to the motor ECU 40 (step S320), and the drive control routine is terminated. In steps S290 to S310, since the torque command Tm1 * of 0 is used, the required torque Tr * is set as the temporary torque Tm2tmp of the motor MG2, and the input / output limits Win and Wout of the battery 50 are set as the torque limits Tmin and Tmax. A value obtained by dividing the motor MG2 by the rotation speed Nm2 is set, and a value obtained by limiting the temporary torque Tm2tmp by the torque limits Tmin and Tmax is set as the torque command Tm2 *. Thus, when there is no output request to the engine 22 and the vehicle speed V is less than the determination vehicle speed Vaj, the operation of the engine 22 is stopped and the vehicle travels only by the torque output from the motor MG2.

  When the vehicle speed V is equal to or higher than the determination vehicle speed Vaj in step S150, it is determined that the rotation of the engine 22 needs to be maintained in order to quickly output power from the engine 22 when the next output request to the engine 22 is made. Then, the following processing is performed. First, a predetermined rotation speed Nset is set as the target rotation speed Ne * of the engine 22 (step S180), the value of the catalyst deterioration suppression flag Fc is checked (step S190), and the catalyst deterioration suppression flag Fc is 0. Sometimes, a fuel cut command for stopping the fuel injection is transmitted to the engine ECU 24 (step S200), and when the catalyst deterioration suppression flag Fc is 1, the intake air is not generated so as to avoid a lean atmosphere in order to execute the catalyst deterioration suppression control. A fuel injection command for executing fuel injection that is stoichiometric with respect to the amount is transmitted to the engine ECU 24 (step S210). Then, the target rotational speed Nm1 * of the motor MG1 is calculated by the following formula (7), and output from the motor MG1 by the formula (8) based on the calculated target rotational speed Nm1 * and the input rotational speed Nm1 of the motor MG1. Power torque command Tm1 * is calculated (step S220), torque command Tm2 * of motor MG2 is set by the processing of steps S290 to S310 using the calculated torque command Tm1 *, and the set torque commands Tm1 * and Tm2 * are set. It transmits to motor ECU40 (step S320), and a drive control routine is complete | finished. Here, Formula (7) is the same as Formula (1). Expression (8) is the same as that obtained by deleting the first term on the right side of Expression (2).

Nm1 * = Ne * ・ (1 + ρ) / ρ-Nm2 / ρ (7)
Tm1 * = k1 (Nm1 * -Nm1) + k2∫ (Nm1 * -Nm1) dt (8)

  When the required power Pe * is determined to be greater than or equal to the threshold value Pstop in step S130 from the state where the rotational speed Ne of the engine 22 is maintained at the predetermined rotational speed Nset, and the output request to the engine 22 is made, the engine 22 is in operation. Since the processing of steps S260 to S320, which is executed when the required power Pe * is equal to or greater than the threshold value Pstop, is executed, the engine 22 is operated at the operating point of the target rotational speed Ne * and the target torque Te * and the battery 50 is turned on. The engine 22, the motor MG1, and the motor MG2 are controlled so that the required torque Tr * is output to the drive shaft 32 within the range of the output limits Win and Wout.

  As described above, when the output request to the engine 22 is not made and the vehicle speed V is equal to or higher than the determination vehicle speed Vaj and the catalyst deterioration suppression flag Fc is 0, the fuel injection to the engine 22 is stopped. The engine 22, motor MG1, and motor MG2 are controlled so that the required torque Tr * is output to the drive shaft 32 within the range of the input / output limits Win and Wout of the battery 50 while the rotation speed Ne is held at the predetermined rotation speed Nset. When the output request to the engine 22 is not made and the vehicle speed V is equal to or higher than the determination vehicle speed Vaj and the catalyst deterioration suppression flag Fc is 1, the fuel injection to the engine 22 is maintained to execute the catalyst deterioration suppression control. In this state, the rotational speed Ne of the engine 22 is held at a predetermined rotational speed Nset and the input / output limits Win and Wout of the battery 50 Within torque demand Tr * to control the engine 22 and the motors MG1 and MG2 to be outputted to the drive shaft 32. FIG. 7 shows an example of an alignment chart when the engine 22 is stopped and when the rotation speed Ne of the engine 22 is held at a predetermined rotation speed Nset. In the figure, the left S-axis indicates the rotational speed of the sun gear, which is the rotational speed Nm1 of the motor MG1, the C-axis indicates the rotational speed of the carrier, which is the rotational speed Ne of the engine 22, and the R-axis indicates the rotational speed Nm2 of the motor MG2. The rotation speed Nr of the ring gear (drive shaft 32) is shown. When an output request to the engine 22 is made when the engine 22 is stopped, the engine 22 is motored to perform fuel injection and ignition, start the engine 22, and then control the throttle opening. However, when the output request to the engine 22 is made when the engine speed Ne is held at the predetermined speed Nset with the fuel injection to the engine 22 stopped, the fuel injection and ignition are performed. By simply starting and controlling the throttle opening, the engine 22 can quickly output power. When a request for output to the engine 22 is made while the engine speed Ne is kept at the predetermined speed Nset while the engine 22 continues to explode and combust by the catalyst deterioration suppression control, the throttle opening degree Power can be quickly output from the engine 22 simply by performing control. As described above, when the vehicle speed V is equal to or higher than the determination vehicle speed Vaj when the output request to the engine 22 is not made, the output request to the engine 22 is made by maintaining the rotation speed Ne of the engine 22 at the predetermined rotation speed Nset. When it is done, power can be output quickly from the engine 22 and the driving feeling can be kept good. Here, the determination vehicle speed Vaj becomes larger as the catalyst temperature Tc is higher. Therefore, the higher the catalyst temperature Tc, the lower the frequency at which the engine speed Ne is held at the predetermined engine speed Nset. This sacrifices the effect of being able to output power quickly from the engine 22 when an output request to the engine 22 is made. However, since the catalyst temperature Tc is high, the catalyst deterioration suppression control is involved. Since the frequency at which the rotation speed Ne of the engine 22 is maintained at the predetermined rotation speed Nset can be reduced, deterioration of the fuel consumption can be suppressed while suppressing the deterioration of the purification catalyst 134a. As described above, the higher the catalyst temperature Tc, the lower the frequency at which the engine speed Ne is held at the predetermined engine speed Nset, thereby suppressing the deterioration of the purification catalyst 134a and the deterioration in fuel consumption and driving feeling. Can be suppressed.

  If the operation of the engine 22 is stopped in step S160, the next time this routine is executed, it is determined in step S120 that the engine 22 is not operating, that is, the engine 22 is stopped, and the required power Pe. It is determined whether or not * is equal to or greater than a threshold value Pstart for starting the engine 22 (step S230). Here, as the threshold value Pstart, a value in the vicinity of the lower limit value of the power region in which the engine 22 can be operated relatively efficiently can be used, but the frequent stop and start of the engine 22 do not occur. It is preferable to use a value larger than the threshold value Pstop for stopping the operation of the engine 22 described above. When the required power Pe * is less than the threshold value Pstart, it is determined that the operation stop state of the engine 22 should be continued, and the processes of steps S170 and S290 to S320 described above are executed.

  If it is determined in step S230 that the required power Pe * is greater than or equal to the threshold value Pstart, a value obtained by adding the output correction value Wa based on the determination vehicle speed Vaj and the storage ratio SOC of the battery 50 to the output limit Wout of the battery 50 is newly added. The output limit Wout is set (step S240), and the engine 22 is started within the set output limit Wout (step S250). When the engine 22 is started, the engine 22 is operated on the fuel efficiency optimal operation line. The target rotational speed Ne *, target torque Te * of the engine 22 and torque commands Tm1 *, Tm2 of the motors MG1, MG2 so as to output the required torque Tr * to the drive shaft 32 within the ranges of the input / output limits Win, Wout of the battery 50. * Set and transmit the above steps S260 to S320 to execute this process To end the routine. Here, in the embodiment, the output correction value Wa is stored in the ROM 74 as an output correction value setting map by predetermining the relationship among the determination vehicle speed Vaj, the storage ratio SOC, and the output correction value Wa, and the determination vehicle speed Vj When the storage ratio SOC is given, the corresponding output correction value Wa is derived from the map. An example of the output correction value setting map is shown in FIG. As shown in the figure, the output correction value Wa is set so as to increase as the determination vehicle speed Vaj increases, and to increase as the power storage ratio SOC increases. Since the determination vehicle speed Vaj is set to a larger value as the catalyst temperature Tc is higher, the output correction value Wa is set to a larger value as the catalyst temperature Tc is higher. The output limit Wout that has been largely corrected by the output correction value Wa is used only during the start of the engine 22, and when the start of the engine 22 is completed, the output limit Wout input in step S100 is used. That is, in the embodiment, the output limit Wout is temporarily corrected to be large only while the engine 22 is started. The engine 22 is started when an output request to the engine 22 is made when the engine 22 is stopped, that is, when the driver depresses the accelerator pedal 83. Considering when the accelerator pedal 83 is depressed by the driver and the engine 22 is started, a large required torque Tr * is required by depressing the accelerator pedal 83. Since the engine 22 has not been started, it is necessary to output a large amount of power in order to output the required torque Tr * from the motor MG2 while the engine 22 is starting. Moreover, since the motoring of the engine 22 is also required for starting the engine 22, this also requires power. Since these powers are covered by the electric power from the battery 50, it is necessary to output a large electric power from the battery 50 when the engine 22 is started. In the embodiment, in order to temporarily output a large amount of electric power from the battery 50, the output limit Wout is corrected to be temporarily increased by the output correction value Wa. Since the electric power required when starting the engine 22 increases as the vehicle speed V increases, the output correction value Wa is set so as to increase as the determination vehicle speed Vaj increases, thereby temporarily setting the output limit Wout. The correction amount can be made appropriate. In addition, since the larger the power storage ratio SOC is, the larger power can be output from the battery 50. By setting the output correction value Wa so that the larger the power storage ratio SOC is, the temporary correction amount of the output limit Wout is determined. Can be made appropriate. The engine 22 is started by outputting torque from the motor MG1 to motoring the engine 22 and performing fuel injection and ignition. During this time, drive control is performed on the drive shaft 32 by outputting torque from the motor MG1. The sum of the cancel torque for canceling the applied torque and the required torque Tr * is output from the motor MG2. Since the details of the control at the time of starting the engine 22 do not form the core of the present invention, further explanation is omitted.

  According to the hybrid vehicle 20 of the embodiment described above, the determination vehicle speed Vaj that keeps the rotational speed Ne of the engine 22 at the predetermined rotational speed Nset when the output request to the engine 22 is not made is the catalyst temperature Tc. The higher the catalyst temperature Tc, the higher the catalyst temperature Tc, and the higher the catalyst temperature Tc, the more frequently the engine speed Ne is maintained at the predetermined engine speed Nset. The frequency held in the number Nset can be reduced. This sacrifices the effect of being able to output power quickly from the engine 22 when an output request to the engine 22 is made. However, since the catalyst temperature Tc is high, the catalyst deterioration suppression control is involved. Since the frequency at which the rotation speed Ne of the engine 22 is maintained at the predetermined rotation speed Nset can be reduced, deterioration of the fuel consumption can be suppressed while suppressing the deterioration of the purification catalyst 134a. Of course, when the vehicle speed V is equal to or higher than the determination vehicle speed Vaj when the output request to the engine 22 is not made, the output request to the engine 22 is made by holding the rotational speed Ne of the engine 22 at the predetermined rotational speed Nset. Sometimes, the engine 22 can output power quickly, and the driving feeling can be kept good. As a result, it is possible to suppress the deterioration of the fuel consumption and the driving feeling while suppressing the deterioration of the purification catalyst 134a.

  Further, according to the hybrid vehicle 20 of the embodiment, an output request to the engine 22 is made when the engine 22 is stopped, and the output limit Wout of the battery 50 is temporarily corrected to be large when the engine 22 is started. By determining the output correction value Wa so as to increase as the determination vehicle speed Vaj increases and to increase as the storage ratio SOC of the battery 50 increases, the temporary correction amount of the output limit Wout is made appropriate. Can do. Of course, when the driver depresses the accelerator pedal 83 while the operation of the engine 22 is stopped because the vehicle speed V is less than the determination vehicle speed Vaj, the power output from the engine 22 is reduced because the engine 22 needs to be started. Even if time is required, the power output from the motor MG2 can be increased, and the deterioration of driving feeling can be suppressed to some extent.

  In the hybrid vehicle 20 of the embodiment, the output limit Wout of the battery 50 is temporarily largely corrected until the start of the engine 22 is completed. However, the battery 50 is used until a predetermined time elapses after the start of the engine 22 is started. The output limit Wout may be temporarily corrected to be large.

  In the hybrid vehicle 20 of the embodiment, the power from the motor MG2 is output to the drive shaft 32. However, as illustrated in the hybrid vehicle 120 of the modified example of FIG. 9, the drive shaft 32 transmits the power from the motor MG2. It may be connected to an axle (an axle connected to the wheels 64a and 64b in FIG. 9) different from the connected axle (the axle to which the drive wheels 63a and 63b are connected). In addition, an engine having an exhaust purification device attached to the exhaust system, a first motor capable of motoring the engine, a second motor capable of outputting driving power, and exchange of electric power with the first motor and the second motor Any type of hybrid vehicle may be used as long as it has a battery capable of.

  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 purification catalyst 134a corresponds to the “catalyst”, the purification device 134 corresponds to the “exhaust purification device”, the engine 22 corresponds to the “engine”, the motor MG1 corresponds to the “first motor”, The motor MG2 corresponds to a “second motor”, the battery 50 corresponds to a “battery”, and a combination of the HVECU 70, the engine ECU 24, the motor ECU 40, and the battery ECU 52 corresponds to a “control unit”.

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

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

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

  20, 120 Hybrid car, 22 engine, 24 engine electronic control unit (engine ECU), 26 crankshaft, 30 planetary gear, 32 drive shaft, 40 motor electronic control unit (motor ECU), 41, 42 inverter, 50 battery, 52 battery electronic control unit (battery ECU), 62 differential gear, 63a, 63b driving wheel, 64a, 64b wheel, 70 hybrid electronic control unit (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, 122 Air cleaner, 124 Slot Valve, 126 fuel injection valve, 128 intake valve, 130 spark plug, 132 piston, 134 purification device, 134a purification catalyst, 134b temperature sensor, 135a air-fuel ratio sensor, 135b oxygen sensor, 136 throttle motor, 138 ignition coil, 140 crank position Sensor, 142 Water temperature sensor, 144 Cam position sensor, 146 Throttle valve position sensor, 148 Air flow meter, 149 Temperature sensor, 150 Variable valve timing mechanism, MG1, MG2 motor.

Claims (2)

An engine in which an exhaust gas purification device having a catalyst for purifying exhaust gas is attached to an exhaust system, a first motor capable of motoring the engine, a second motor capable of outputting driving power, and the first A battery capable of exchanging electric power with the motor and the second motor, and when the vehicle speed is less than the determination vehicle speed when there is no output request to the engine, the engine speed is set to 0 and the operation of the engine is stopped. The engine, the first motor, and the second motor are controlled, and when there is no output request to the engine, when the vehicle speed is equal to or higher than the determination vehicle speed and the deterioration of the catalyst needs to be suppressed, Controlling the engine, the first motor, and the second motor so that the rotation of the engine is maintained with fuel injection to the engine; The engine to the rotation of the engine by stopping the fuel injection into the engine is maintained when the vehicle speed is not necessary to suppress the deterioration of the catalyst effected even if the above said determining vehicle speed when there is no output request And a hybrid vehicle comprising: control means for controlling the first motor and the second motor;
The control means is means for using a larger value as the determination vehicle speed as the temperature of the catalyst is higher.
A hybrid vehicle characterized by that. The hybrid vehicle according to claim 1,
The control means is means for controlling the first motor and the second motor within a range of output restriction based on the state of the battery, and further, from a state where there is no output request to the engine to the engine. When an output request is made, the output limit is corrected and used by a correction value that increases as the determination vehicle speed increases and / or as the amount of power stored in the battery increases, until a predetermined time elapses.
A hybrid vehicle characterized by that.

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