JP5246090B2 - Hybrid vehicle and control method thereof - Google Patents

Description

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

  Conventionally, this type of hybrid vehicle can output power to an engine equipped with a purification device having a purification catalyst for purifying exhaust, a first motor capable of cranking the engine, and a drive shaft connected to the axle. A second motor, a three-axis planetary gear mechanism connected to the output shaft of the engine, the rotation shaft of the first motor, and the drive shaft, and a battery for exchanging power with the first motor and the second motor, There has been proposed a vehicle capable of traveling at a virtual shift position (sequential shift position) that enables a virtual shift change of 1 to 6 speeds by a driver's operation (see, for example, Patent Document 1). In this hybrid vehicle, when a deceleration request based on accelerator-off is made when a sequential shift position is selected, the engine in a fuel cut state is motored by the first motor to rotate at a rotational speed corresponding to the shift position and the vehicle speed. Thus, a braking force by so-called engine brake is applied to the drive shaft.

JP 2007-186111 A

  In such a hybrid vehicle, when the accelerator is turned off when the temperature of the purification catalyst is low and the purification catalyst is not activated, the engine in a state where the fuel injection is stopped is motored by the first motor to apply the braking force to the drive shaft. If the control is performed, when the fuel injection supplied to the engine is corrected for the reason of stabilization of combustion when restarting the fuel injection after that, the exhaust of the engine cannot be sufficiently purified and the emission deteriorates. May be incurred.

  The main purpose of the hybrid vehicle and the control method thereof according to the present invention is to suppress the deterioration of emissions.

  The hybrid vehicle of the present invention and its control method employ the following means in order to achieve the main object described above.

The hybrid vehicle of the present invention
An internal combustion engine having a purification device having a purification catalyst for purifying exhaust gas in an exhaust system;
A generator capable of inputting and outputting power;
It is connected to three shafts, that is, a drive shaft coupled to an axle, an output shaft of the internal combustion engine, and a rotating shaft of the generator, and the remaining power is determined based on power input / output to / from any two of the three shafts. 3-axis power input / output means for inputting / outputting power to the shaft;
An electric motor capable of inputting and outputting power to the drive shaft;
Power storage means capable of exchanging electric power with the generator and the motor;
The lower limit of the temperature range in which the temperature of the purification catalyst is activated when the shift position is at the braking position where a large braking force is required when the accelerator is off compared to the normal driving position and the accelerator is off. The internal combustion engine and the generator so that the vehicle travels with the required braking force required for the vehicle with stop of fuel injection of the internal combustion engine and motoring of the internal combustion engine by the generator Motoring braking control for controlling the motor and the motor, and driving braking control for controlling the internal combustion engine, the generator and the motor so as to travel with the required braking force with fuel injection of the internal combustion engine. Priority is given to motoring braking control, and the motoring braking control is performed when the temperature of the purification catalyst is lower than the lower limit temperature. An accelerator-off time control means for performing preferentially the operation braking control of said operating brake control,
It is a summary to provide.

  In the hybrid vehicle of the present invention, the temperature of the purifying catalyst is the temperature of the purifying catalyst when the shift position is at the braking position where a larger braking force is required when the accelerator is off than when the accelerator is off and the accelerator is off. When the temperature is equal to or higher than the lower limit temperature set as the lower limit of the temperature range to be activated, the internal combustion engine travels with the required braking force required for the vehicle with the stop of fuel injection of the internal combustion engine and motoring of the internal combustion engine by the generator Motoring braking control for controlling the internal combustion engine, the generator and the motor so as to travel with the required braking force accompanying the fuel injection of the internal combustion engine and the motoring braking control for controlling the motor, the generator and the motor Execute with priority. Thereby, the braking force by what is called an engine brake can be made to act on a vehicle. On the other hand, when there is a shift position at the braking position where a large braking force is required when the accelerator is off compared to the normal driving position and the accelerator is off and the temperature of the purification catalyst is lower than the lower limit temperature, motoring braking is performed. Of the control and the operation braking control, the operation braking control is preferentially executed. This makes it difficult to stop the fuel injection of the internal combustion engine, so that it is possible to suppress the deterioration of the emission that may occur when the fuel injection is stopped and restarted in a state where the purification catalyst is not activated. Here, the “three-axis power input / output means” may be a single pinion type or double pinion type planetary gear mechanism, or may be a differential gear.

  In such a hybrid vehicle of the present invention, the accelerator-off time control means responds to the required braking force when the shift position is at the braking position and the accelerator is off, and when the temperature of the purification catalyst is equal to or higher than the lower limit temperature. The self-sustained operation braking control is executed when the required braking power is within the first power range, and the motoring braking control is executed when the required braking power is outside the first power range. When the required temperature is less than the lower limit temperature, the self-sustained operation braking control is executed when the required braking power is within a second power range wider than the first power range, and the required braking power is It may be a means for executing the motoring braking control when out of a power range. In this case, the first power range and the second power range are power ranges that are determined as a range that travels by the required braking force by regenerative braking of the electric motor without motoring of the internal combustion engine. It can also be.

  Further, in the hybrid vehicle of the present invention, the accelerator-off time control means is configured such that when the shift position is at the braking position and the accelerator is off, and the temperature of the purification catalyst is less than the lower limit temperature, the purification catalyst. It is also possible to make the required braking force a smaller braking force than when the temperature is equal to or higher than the lower limit temperature.

The hybrid vehicle control method of the present invention includes:
An internal combustion engine having a purification device having a purification catalyst for purifying exhaust gas in an exhaust system, a generator capable of inputting and outputting power, a drive shaft connected to an axle, an output shaft of the internal combustion engine, and the generator A three-axis power input / output means connected to the three axes of the rotating shaft and inputting / outputting power to / from the remaining shaft based on power input / output to / from any two of the three axes; A control method for a hybrid vehicle comprising: an electric motor capable of inputting / outputting power; and an electric storage means capable of exchanging electric power with the electric generator and the electric motor,
The lower limit of the temperature range in which the temperature of the purification catalyst is activated when the shift position is at the braking position where a large braking force is required when the accelerator is off compared to the normal driving position and the accelerator is off. The internal combustion engine and the generator so that the vehicle travels with the required braking force required for the vehicle with stop of fuel injection of the internal combustion engine and motoring of the internal combustion engine by the generator Motoring braking control for controlling the motor and the motor, and driving braking control for controlling the internal combustion engine, the generator and the motor so as to travel with the required braking force with fuel injection of the internal combustion engine. The motoring braking control is executed with priority, and the motoring braking control is performed when the temperature of the purification catalyst is lower than the lower limit temperature. Preferentially executes the operation braking control of said operating brake control,
It is characterized by that.

  In this hybrid vehicle control method of the present invention, when the shift position is at the braking position where a large braking force is required when the accelerator is off compared to the normal driving position and the accelerator is off, the temperature of the purification catalyst is high. When the temperature is equal to or higher than the lower limit temperature defined as the lower limit of the temperature range in which the purification catalyst is activated, the vehicle travels with the required braking force required for the vehicle with the stop of fuel injection of the internal combustion engine and motoring of the internal combustion engine by the generator Among the motoring braking control for controlling the internal combustion engine, the generator and the motor, and the operation braking control for controlling the internal combustion engine, the generator and the motor so as to travel with the required braking force accompanying the fuel injection of the internal combustion engine. Priority is given to ring braking control. Thereby, the braking force by what is called an engine brake can be made to act on a vehicle. On the other hand, when there is a shift position at the braking position where a large braking force is required when the accelerator is off compared to the normal driving position and the accelerator is off and the temperature of the purification catalyst is lower than the lower limit temperature, motoring braking is performed. Of the control and the operation braking control, the operation braking control is preferentially executed. This makes it difficult to stop the fuel injection of the internal combustion engine, so that it is possible to suppress the deterioration of the emission that may occur when the fuel injection is stopped and restarted in a state where the purification catalyst is not activated. Here, the “three-axis power input / output means” may be a single pinion type or double pinion type planetary gear mechanism, or may be a differential gear.

1 is a configuration diagram showing an outline of a configuration of a hybrid vehicle 20 as an embodiment of the present invention. 2 is a configuration diagram showing an outline of the configuration of an engine 22. FIG. It is a flowchart which shows an example of the control routine at the time of accelerator off performed by the electronic control unit for hybrids 70 of an Example. It is explanatory drawing which shows an example of the map for request | requirement braking torque setting. It is explanatory drawing which shows an example of the collinear diagram which shows the dynamic relationship between the rotation speed and torque in the rotation element of the power distribution integration mechanism 30 when driving | running | working while idling the engine 22 at the time of accelerator off. It is explanatory drawing which shows an example of the map for target rotation speed setting. It is explanatory drawing which shows an example of the collinear diagram which shows the dynamic relationship of the rotation speed and torque in the rotation element of the power distribution integration mechanism 30 at the time of driving | running | working with an engine brake at the time of an accelerator off. 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 the figure, the hybrid vehicle 20 of the embodiment includes an engine 22, a three-shaft power distribution / integration mechanism 30 connected to a crankshaft 26 as an output shaft of the engine 22 via a damper 28, and power distribution / integration. A motor MG1 capable of generating electricity connected to the mechanism 30, a reduction gear 35 attached to a ring gear shaft 32a as a drive shaft connected to the power distribution and integration mechanism 30, a motor MG2 connected to the reduction gear 35, And a hybrid electronic control unit 70 for controlling the entire vehicle.

  The engine 22 is configured as an internal combustion engine capable of outputting power using a hydrocarbon-based fuel such as gasoline or light oil, and the air purified by an air cleaner 122 is passed through a throttle valve 124 as shown in FIG. Inhalation and gasoline are injected from the fuel injection valve 126 to mix the sucked air and gasoline, and this mixture is sucked into the combustion chamber through the intake valve 128 and explosively burned by an electric spark from the spark plug 130. Thus, the reciprocating motion of the piston 132 pushed down by the energy is converted into the rotational motion of the crankshaft 26. A purification device 134 having a purification catalyst (three-way catalyst) 134a for removing harmful components such as carbon monoxide (CO), hydrocarbons (HC), and nitrogen oxides (NOx) is attached to the exhaust system of the engine 22. The exhaust from the engine 22 is discharged to the outside air through the purification device 134.

  The engine 22 is controlled by an engine electronic control unit (hereinafter referred to as an engine ECU) 24. The engine ECU 24 is configured as a microprocessor centered on the CPU 24a, and includes a ROM 24b that stores a processing program, a RAM 24c that temporarily stores data, an input / output port and a communication port (not shown), in addition to the CPU 24a. . The engine ECU 24 receives signals from various sensors that detect the state of the engine 22, for example, a crank position from the crank position sensor 140 that detects the rotational position of the crankshaft 26, and a water temperature that detects the temperature of cooling water in the engine 22. The cam position for detecting the coolant temperature Tw from the sensor 142, the in-cylinder pressure from a pressure sensor (not shown) attached to the combustion chamber, 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 The cam position from the sensor 144, the throttle position from the throttle valve position sensor 146 for detecting the position of the throttle valve 124, the amount of intake air Qa from the air flow meter 148 attached to the intake pipe, and the temperature sensor also attached to the intake pipe The intake air temperature Ta from 49, the air-fuel ratio from the air-fuel ratio sensor 135a, the oxygen signal from the oxygen sensor 135b, the catalyst temperature Tc from the temperature sensor 135c that is attached to the purification device 134 and detects the temperature of the purification catalyst 134a, etc. are input. Is entered through the 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 is in communication with the hybrid electronic control unit 70, controls the operation of the engine 22 by a control signal from the hybrid electronic control unit 70, and outputs data related to the operation state of the engine 22 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 the crank position from the crank position sensor 140.

  The power distribution and integration mechanism 30 includes an external gear sun gear 31, an internal gear ring gear 32 arranged concentrically with the sun gear 31, a plurality of pinion gears 33 that mesh with the sun gear 31 and mesh with the ring gear 32, A planetary gear mechanism is provided that includes a carrier 34 that holds a plurality of pinion gears 33 so as to rotate and revolve, and that performs differential action using the sun gear 31, the ring gear 32, and the carrier 34 as rotational elements. In the power distribution and integration mechanism 30, the crankshaft 26 of the engine 22 is connected to the carrier 34, the motor MG1 is connected to the sun gear 31, and the reduction gear 35 is connected to the ring gear 32 via the ring gear shaft 32a. When functioning as a generator, power from the engine 22 input from the carrier 34 is distributed according to the gear ratio between the sun gear 31 side and the ring gear 32 side, and when the motor MG1 functions as an electric motor, the engine input from the carrier 34 The power from 22 and the power from the motor MG1 input from the sun gear 31 are integrated and output to the ring gear 32 side. The power output to the ring gear 32 is finally output from the ring gear shaft 32a to the drive wheels 63a and 63b of the vehicle via the gear mechanism 60 and the differential gear 62.

  The motor MG1 and the motor MG2 are both configured as well-known synchronous generator motors that can be driven as generators and can be driven as motors, and exchange power with the battery 50 via inverters 41 and 42. The power line 54 connecting the inverters 41 and 42 and the battery 50 is configured as a positive electrode bus and a negative electrode bus shared by the inverters 41 and 42, and the electric power generated by one of the motors MG1 and MG2 It can be consumed by a motor. Therefore, battery 50 is charged / discharged by electric power generated from one of motors MG1 and MG2 or insufficient electric power. If the balance of electric power is balanced by the motors MG1 and MG2, the battery 50 is not charged / discharged. The motors MG1 and MG2 are both driven and controlled by a motor electronic control unit (hereinafter referred to as a motor ECU) 40. The motor ECU 40 detects signals necessary for driving and controlling the motors MG1 and MG2, such as signals from rotational position detection sensors 43 and 44 that detect the rotational positions of the rotors of the motors MG1 and MG2, and current sensors (not shown). The phase current applied to the motors MG1 and MG2 to be applied is input, and a switching control signal to the inverters 41 and 42 is output from the motor ECU 40. The motor ECU 40 is in communication with the hybrid electronic control unit 70, controls the driving of the motors MG1 and MG2 by a control signal from the hybrid electronic control unit 70, and, if necessary, data on the operating state of the motors MG1 and MG2. Output to the hybrid electronic control unit 70. The motor ECU 40 also calculates the rotational speeds Nm1 and Nm2 of the motors MG1 and MG2 based on signals from the rotational position detection sensors 43 and 44.

  The battery 50 is managed by a battery electronic control unit (hereinafter referred to as a battery ECU) 52. The battery ECU 52 receives signals necessary for managing the battery 50, for example, an inter-terminal voltage Vb from the voltage sensor 51 a installed between the terminals of the battery 50, and a power line 54 connected to the output terminal of the battery 50. The charging / discharging current Ib from the attached current sensor 51b, the battery temperature Tb from the temperature sensor 51c attached to the battery 50, and the like are input. Output to the control unit 70. Further, the battery ECU 52 calculates the remaining capacity (SOC) based on the integrated value of the charge / discharge current Ib detected by the current sensor 51b in order to manage the battery 50, or calculates the remaining capacity (SOC) and battery temperature. Based on Tb, input / output limits Win and Wout, which are the maximum allowable power that may charge / discharge the battery 50, are calculated. The input / output limits Win and Wout of the battery 50 are set to the basic values of the input / output limits Win and Wout based on the battery temperature Tb, and the output limiting correction coefficient and input based on the remaining capacity (SOC) of the battery 50 It can be set by setting a correction coefficient for restriction and multiplying the basic value of the set input / output restrictions Win and Wout by the correction coefficient.

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

  Further, in the hybrid vehicle 20 of the embodiment, as the shift position SP of the shift lever 81, the parking position (P position) used during parking, the reverse position (R position) for reverse travel, the neutral position (N position), the forward position In addition to the driving position for driving (D position), a sequential shift position (S position), an upshift instruction position, and a downshift instruction position are prepared. When the shift position SP is in the D position, the hybrid vehicle 20 of the embodiment performs drive control so that the engine 22 is operated efficiently and the power output response is relatively good. Further, when the shift position SP is the S position, it is possible to change the ratio of the rotational speed of the engine 22 to the vehicle speed V, for example, in six steps (S1 to S6) mainly during deceleration, and stop fuel injection to the engine 22 At the same time, the engine MG1 forcibly rotates the engine 22 at a rotational speed corresponding to the vehicle speed V and the shift position SP (S1 to S6), so-called engine braking that causes the intake / exhaust resistance of the engine 22 to act on the ring gear shaft 32a is possible. It becomes. In the embodiment, when the shift lever 81 is set to the S position by the driver, the shift position SP is set to S4 in the fourth stage, and the shift position sensor 82 detects that the shift position SP = S4. Thereafter, when the shift lever 81 is set to the upshift instruction position, the shift position SP is raised by one step (upshifted), and when the shift lever 81 is set to the downshift instruction position, the shift position SP is incremented by one step. The shift position sensor 82 detects and outputs the current shift position SP according to the operation of the shift lever 81.

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

  Next, the operation of the hybrid vehicle 20 of the embodiment thus configured, particularly the operation when the accelerator is off will be described. FIG. 3 is a flowchart showing an example of an accelerator-off time control routine executed by the hybrid electronic control unit 70. This routine is repeatedly executed every predetermined time (for example, every several milliseconds) when the accelerator is off.

  When the accelerator off-time control routine is executed, the CPU 72 of the hybrid electronic control unit 70 first starts the shift position SP from the shift position sensor 82, the vehicle speed V from the vehicle speed sensor 88, the rotational speed Nm1 of the motors MG1 and MG2. , Nm2, input limit Win of the battery 50, catalyst temperature Tc from the temperature sensor 135c, and the like are input (step S100). Here, the rotational speeds Nm1 and Nm2 of the motors MG1 and MG2 are input from the motor ECU 40 by communication from those calculated based on the rotational positions of the rotors of the motors MG1 and MG2 detected by the rotational position detection sensors 43 and 44. To do. Also, the input limit Win of the battery 50 is input from the battery ECU 52 by communication from the battery ECU 52 that is set within a range of 0 or less based on the battery temperature Tb of the battery 50 and the remaining capacity (SOC) of the battery 50. did.

  When the data is thus input, the required braking torque Tr * to be output to the ring gear shaft 32a as the drive shaft connected to the drive wheels 63a and 63b as the torque required for the vehicle based on the input shift position SP and the vehicle speed V. And the required braking power Pr * to be output to the ring gear shaft 32a is set (step S110). In the embodiment, the required braking torque Tr * is determined in advance by storing the relationship between the shift position SP, the vehicle speed V, and the required braking torque Tr * in the ROM 74 as a required torque setting map, and the accelerator opening Acc and the vehicle speed V are stored. And the corresponding required braking torque Tr * is derived and set from the stored map. FIG. 4 shows an example of the required braking torque setting map. As shown in the figure, the required braking torque Tr * tends to decrease as the vehicle speed V increases (increases as a braking force), and decreases as the shift position SP decreases from S6 to S1 (increases as a braking force). The trend was set. The required braking power Pr * can be calculated by multiplying the set required braking torque Tr * by the rotation speed Nr of the ring gear shaft 32a. The rotational speed Nr of the ring gear shaft 32a is obtained by multiplying the vehicle speed V by a conversion factor k (Nr = k · V), or the rotational speed Nm2 of the motor MG2 is divided by the gear ratio Gr of the reduction gear 35 (Nr = Nm2 / Gr).

  Subsequently, the shift position SP is checked (step S120). When the shift position SP is the D position, the input limit Win of the battery 50 is set as the control input limit Win * (step S130), and the required braking power Pr * is controlled. The input limit Win * is compared (step S160). The required braking power Pr * and the control input limit Win * are compared by stopping the fuel injection to the engine 22 and forcibly rotating the engine 22 by the motor MG1 to indirectly increase the intake / exhaust resistance of the engine 22. This is a process for determining whether or not the vehicle travels with a so-called engine brake applied to the vehicle.

  When the required braking power Pr * is equal to or greater than the control input limit Win * (when the required braking power Pr * is within the range of the braking input limit Win *), it is determined that the vehicle travels without engine braking, and the engine 22 Is transmitted to the engine ECU 24 (step S170), the torque command Tm1 * of the motor MG1 is set to 0 (step S180), and the torque command Tm1 * set to the required braking torque Tr * is set. Is divided by the gear ratio ρ of the power distribution and integration mechanism 30 and further divided by the gear ratio Gr of the reduction gear 35 to obtain a provisional torque Tm2tmp which is a provisional value of the torque to be output from the motor MG2. ) (Step S220), and the control input limit Win * and the set torque command Tm1 * are multiplied by the current rotational speed Nm1 of the motor MG1. A torque limit Tm2min as a lower limit of the torque that may be output from the motor MG2 by dividing the difference from the obtained power consumption (generated power) of the motor MG1 by the rotation speed Nm2 of the motor MG2 is calculated by the following equation (2). (Step S230), the set temporary torque Tm2tmp is limited by the torque limit Tm2min according to the equation (3) and the torque command Tm2 * of the motor MG2 is set (Step S240), and the torque commands Tm1 * and Tm2 * of the motors MG1 and MG2 are set. Is transmitted to the motor ECU 40 (step S250), and this routine is terminated. The engine ECU 24 that has received the self-sustained operation command performs control such as intake air amount control, fuel injection control, and ignition control so that the engine 22 rotates at a predetermined rotational speed (for example, idle rotational speed). The motor ECU 40 that has received the torque commands Tm1 * and Tm2 * controls the switching elements of the inverters 41 and 42 so that the motor MG1 is driven by the torque command Tm1 * and the motor MG2 is driven by the torque command Tm2 *. To do. FIG. 5 shows an example of a collinear diagram showing a dynamic relationship between the rotational speed and torque in the rotating elements of the power distribution and integration mechanism 30 when the engine 22 is running while idling while the accelerator is off. In the figure, the left S-axis indicates the rotation speed of the sun gear 31 that is the rotation speed Nm1 of the motor MG1, the C-axis indicates the rotation speed of the carrier 34 that is the rotation speed Ne of the engine 22, and the R-axis indicates the rotation speed of the motor MG2. The rotational speed Nr of the ring gear 32 obtained by dividing the number Nm2 by the gear ratio Gr of the reduction gear 35 is shown. Expression (1) can be easily derived by using this alignment chart. By such control, the engine 22 can travel while outputting the braking torque based on the required braking torque Tr * to the ring gear shaft 32a as the drive shaft while autonomously operating the engine 22 (without engine braking). In this case, the battery 50 is charged with the electric power generated by the regenerative driving of the motor MG2.

Tm2tmp = (Tr * + Tm1 * / ρ) / Gr (1)
Tm2min = (Win * -Tm1 * ・ Nm1) / Nm2 (2)
Tm2 * = max (Tm2tmp, Tm2min) (3)

  When the required braking power Pr * is less than the control input limit Win * in step S160 (when the required braking power Pr * is out of the range of the braking input limit Win *), it is determined that the vehicle travels with the engine brake, A fuel cut command for stopping fuel injection of the engine 22 is transmitted to the engine ECU 24 (step S190), and a target rotational speed Ne * of the engine 22 is set based on the shift position SP and the vehicle speed V (step S200). . The engine ECU 24 that has received the fuel cut command stops fuel injection control and ignition control. Further, in the embodiment, the target rotational speed Ne * of the engine 22 is stored in the ROM 74 as a target rotational speed setting map by predetermining the relationship among the shift position SP, the vehicle speed V, and the target rotational speed Ne *. When the position SP and the vehicle speed V are given, the corresponding target rotational speed Ne * is derived and set from the stored map. FIG. 6 shows an example of the target rotation speed setting map. As shown in the figure, the target rotational speed Ne * tends to be larger when the shift position SP is at the S position than when it is at the D position, and when the shift position SP is at the S position, In order to approximate the engine brake of a vehicle equipped with a transmission, the vehicle tends to increase as the vehicle speed V increases and to increase as the shift position SP decreases from S6 to S1.

  When the target rotational speed Ne * of the engine 22 is thus set, the target rotational speed Ne * of the engine 22, the rotational speed Nm2 of the motor MG2, the gear ratio ρ of the power distribution and integration mechanism 30, and the gear ratio Gr of the reduction gear 35 are used. The target rotational speed Nm1 * of the motor MG1 is calculated by the following equation (4), the calculated target rotational speed Nm1 *, the input rotational speed Nm1 of the motor MG1, the target torque Te * of the engine 22, and the gear of the power distribution and integration mechanism 30 Based on the ratio ρ, the torque command Tm1 * of the motor MG1 is calculated by the equation (5) (step S210), the torque command Tm2 * of the motor MG2 is set (steps S220 to S240), and the torque commands of the motors MG1 and MG2 are set. Tm1 * and Tm2 * are transmitted to the motor ECU 40 (step S250), and this routine ends. Here, Expression (4) is a dynamic relational expression for the rotating elements of the power distribution and integration mechanism 30. FIG. 7 shows an example of a collinear diagram showing the dynamic relationship between the rotational speed and torque in the rotating elements of the power distribution and integration mechanism 30 when traveling with the engine brake when the accelerator is off. Expression (4) can be easily derived by using this alignment chart. Expression (5) is a relational expression in feedback control for rotating the motor MG1 at the target rotational speed Nm1 *. In Expression (5), “k1” in the second term on the right side is a gain of a proportional term. “K2” in the third term on the right side is the gain of the integral term. By such control, it is possible to travel by outputting a braking torque based on the required braking torque Tr * to the ring gear shaft 32a as a drive shaft with an engine brake.

Nm1 * = Ne * ・ (1 + ρ) / ρ-Nm2 / (Gr ・ ρ) (4)
Tm1 * =-ρ ・ Te * / (1 + ρ) + k1 ・ (Nm1 * -Nm1) + k2 ・ ∫ (Nm1 * -Nm1) dt (5)

  When the shift position SP is the S position in step S120, the catalyst temperature Tc is compared with the threshold value Tcref (step S140). Here, the threshold value Tcref is determined as the lower limit of the temperature range in which the purification catalyst 134a is activated. For example, 400 ° C, 450 ° C, 500 ° C, or the like can be used. When the catalyst temperature Tc is equal to or higher than the threshold value Tcref, it is determined that the purification catalyst 134a is activated, the predetermined power Ws is set as the control input limit Win * (step S150), and the processes of steps S160 to S250 are executed. This routine ends. Here, the predetermined power Ws is a battery that makes it easy to use the engine brake when the accelerator is off and increases the time until the battery 50 is in a high remaining capacity state (for example, 70% or 80%) close to full charge. 50, which can be determined in advance by experiments or the like, and a value larger than the input limit Win of the battery 50 (small absolute value), that is, when the S position is not selected as the shift position SP. Larger values are used. Therefore, in this case, the engine brake can be used more easily than when the shift position SP is the D position, and a good feeling can be given to the driver.

  When the catalyst temperature Tc is lower than the threshold value Tcref in step S140, it is determined that the purification catalyst 134a is not activated, the input limit Win of the battery 50 is set as the control input limit Win * (step S130), and steps S160 to S250. The process is executed and this routine is terminated. If the engine brake is used when the accelerator is off in the state where the purification catalyst 134a is not activated, the reason is that the combustion of the engine 22 is stabilized when the accelerator pedal 83 is subsequently depressed and the fuel injection of the engine 22 is resumed. Therefore, when the fuel increase correction is performed, the exhaust from the engine 22 cannot be sufficiently purified by the purification catalyst 134a, and the emission may be deteriorated. On the other hand, in the embodiment, when the accelerator is off in a state where the purification catalyst 134a is not activated, the control input limit Win * is smaller (the absolute value is larger) than when the purification catalyst 134a is activated. Therefore, it becomes difficult to use the engine brake, that is, the engine 22 is easily operated independently, and the deterioration of the emission can be suppressed.

  According to the hybrid vehicle 20 of the embodiment described above, when the accelerator position is off at the shift position SP at the S position, the required braking power Pr * corresponding to the required braking torque Tr * is the battery when the catalyst temperature Tc is equal to or higher than the threshold value Tcref. A braking torque based on the required braking torque Tr * is output to the ring gear shaft 32a while the engine 22 is autonomously operated (without engine braking) when the power is greater than or equal to 50 (the absolute value is small) greater than a predetermined power Ws. The engine 22 and the motors MG1 and MG2 are controlled so as to travel, and when the required braking power Pr * is less than the predetermined power Ws, the ring gear shaft 32a as the drive shaft is set to the required braking torque Tr * with a so-called engine brake. The engine 22 and the motor are driven to output the braking torque based on the When the catalyst temperature Tc is less than the threshold value Tcref, when the required braking power Pr * is equal to or greater than the input limit Win of the battery 50, the engine 22 is operated autonomously while the required braking torque Tr * is applied to the ring gear shaft 32a. The engine 22 and the motors MG1 and MG2 are controlled so that the vehicle travels by outputting a braking torque based on the above, and when the required braking power Pr * is less than the input limit Win of the battery 50, a ring gear as a drive shaft accompanied by a so-called engine brake Since the engine 22 and the motors MG1, MG2 are controlled so as to travel by outputting a braking torque based on the required braking torque Tr * to the shaft 32a, the engine brake is easily used when the catalyst temperature Tc is equal to or higher than the threshold value Tcref. Gives a good feeling to the catalyst temperature Tc is at less than the threshold value Tcref can fuel injection of the engine 22 to suppress the deterioration of emission less likely to be stopped.

  In the hybrid vehicle 20 of the embodiment, the required braking torque Tr * is set without considering the catalyst temperature Tc. However, when the shift position SP is the S position, the required braking torque Tr * is considered in consideration of the catalyst temperature Tc. May be set. In this case, for example, when the shift position SP is the S position and the catalyst temperature Tc is equal to or higher than the threshold value Tcref, the required braking torque Tr * is set according to S1 to S6 as in the embodiment, and the catalyst temperature Tc is set to the threshold value Tcref. If it is less, the same required braking torque Tr * may be set as when the shift position SP is the D position. In this way, when the shift position SP is at the S position, the required braking torque Tr that is larger (smaller as the braking torque) than when the purification catalyst 134a is activated when the purification catalyst 134a is not activated. Since * is set, the engine brake is less likely to be used, that is, the engine 22 is more likely to be operated independently, and the deterioration of emissions can be further suppressed. When the shift position SP is the S position and the catalyst temperature Tc is less than the threshold value Tcref, the torque is not limited to the same required braking torque Tr * that is set when the shift position SP is the D position, and the torque according to S1 to S6. Larger torque (small torque on the braking side) may be set as the required braking torque Tr *. In addition, when the shift position SP is the S position and the catalyst temperature Tc is less than the threshold value Tcref, when a torque larger than the torque corresponding to S1 to S6 is set as the required braking torque Tr *, the predetermined torque is set regardless of the catalyst temperature Tc. The power Ps may be set as the control input limit Win *. Even in such a case, by setting the required braking torque Tr * to be a small torque on the braking side, the engine brake is less likely to be used than when the catalyst temperature Tc is equal to or higher than the threshold value Tcref, that is, the engine 22 is easily operated independently. Deterioration of emissions can be suppressed.

  In the hybrid vehicle 20 of the embodiment, when the shift position SP is the S position and the catalyst temperature Tc is less than the threshold value Tcref, the input limit Win of the battery 50 is set as the control input limit Win *. However, the present invention is not limited to this. The control input limit Win * is set within a range that is greater than or equal to the input limit Win of the battery 50 and less than the predetermined power Ws (the absolute value is less than the absolute value of the input limit Win and greater than the absolute value of the predetermined power Ws). If it is.

  In the hybrid vehicle 20 of the embodiment, a sequential position (S position) is assumed as a braking position, but the required braking torque Tr * when the accelerator is off is smaller than the D position instead of or in addition to the S position. When a single-stage braking position (B position) is provided (which increases as braking torque), when the shift position SP is in the B position and the accelerator is off, the shift position SP is in the S position and the accelerator is off. The same control as in the above may be performed.

  In the hybrid vehicle 20 of the embodiment, the catalyst temperature Tc is detected by the temperature sensor 135c attached to the purification device 134. However, the temperature sensor 135c is not provided, and the integrated value of the intake air amount Qa, the intake air temperature Ta, and the cooling are not provided. The temperature of the purification catalyst 134a may be estimated based on the water temperature Tw or the like.

  In the hybrid vehicle 20 of the embodiment, the power of the motor MG2 is shifted by the reduction gear 35 and output to the ring gear shaft 32a. However, as illustrated in the hybrid vehicle 120 of the modified example of FIG. May be output to an axle (an axle connected to the wheels 64a and 64b in FIG. 8) different from an axle to which the ring gear shaft 32a is connected (an axle to which the drive wheels 63a and 63b are connected).

  Moreover, it is not limited to what is applied to such a hybrid vehicle, It is good also as forms of vehicles other than a motor vehicle. Moreover, it is good also as a form of the control method of a hybrid vehicle.

  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 in which the purification device 134 having the purification catalyst 134a is attached to the exhaust system corresponds to the “internal combustion engine”, the motor MG1 corresponds to the “generator”, and the power distribution and integration mechanism 30 corresponds to the “three-shaft”. The motor temperature MG2 corresponds to the “electric motor”, the battery 50 corresponds to the “power storage means”, and when the accelerator position is off when the shift position SP is the S position, the catalyst temperature Tc is the threshold value Tcref. At this time, when the required braking power Pr * corresponding to the required braking torque Tr * is greater than a predetermined power Ws greater than the input limit Win of the battery 50 (small absolute value), the engine 22 is operated independently (with engine braking). The self-sustained operation command is issued so that the ring gear shaft 32a travels by outputting a braking torque based on the required braking torque Tr *. When the required braking power Pr * is less than the predetermined electric power Ws, the drive shaft is accompanied by a so-called engine brake, and is transmitted to the CU 24 or set to the motor ECU 40 by setting torque commands Tm1 * and Tm2 * of the motors MG1 and MG2. The motor ECU 40 transmits a fuel cut command to the engine ECU 24 to output a braking torque based on the required braking torque Tr * to the ring gear shaft 32a and sets torque commands Tm1 * and Tm2 * of the motors MG1 and MG2. When the catalyst temperature Tc is less than the threshold value Tcref, when the required braking power Pr * is equal to or higher than the input limit Win of the battery 50, the engine 22 is operated autonomously while the ring gear shaft 32a is braked based on the required braking torque Tr *. Independent engine operation command to run with torque output When the required braking power Pr * is the input limit Win of the battery 50 and so-called engine braking is performed, the torque command Tm1 *, Tm2 * of the motors MG1, MG2 is set and transmitted to the motor ECU 40. A fuel cut command is transmitted to the engine ECU 24 and torque commands Tm1 * and Tm2 * of the motors MG1 and MG2 are set so that the ring gear shaft 32a as a drive shaft outputs a braking torque based on the required braking torque Tr * and travels. The hybrid electronic control unit 70 that executes the accelerator-off time control routine of FIG. 3 that is transmitted to the motor ECU 40, and controls the engine 22 based on the stand-alone operation command or the fuel injection control or stop control based on the fuel cut command ECU 24 for stopping the engine and torque command Tm1 The motor ECU 40 that controls the motors MG1 and MG2 based on * and Tm2 * corresponds to “accelerator off time control means”.

  Here, the “internal combustion engine” is not limited to an internal combustion engine that outputs power using a hydrocarbon fuel such as gasoline or light oil, but a purification device having a purification catalyst for purifying exhaust gas is attached to the exhaust system. As long as it is given, it does not matter. The “generator” is not limited to the motor MG1 configured as a synchronous generator motor, and may be any type of generator as long as it can input and output power, such as an induction motor. The “3-axis power input / output means” is not limited to the power distribution / integration mechanism 30; it can be connected to four or more shafts by using a double pinion planetary gear mechanism or a combination of a plurality of planetary gear mechanisms. Connected to the three shafts of the drive shaft connected to the axle, the output shaft of the internal combustion engine, and the rotating shaft of the generator As long as the power is input / output to / from the remaining shafts based on the power input / output to / from any one of the two shafts, any configuration may be used. The “storage means” is not limited to the battery 50 as a secondary battery, and may be anything as long as it can exchange power with a generator or an electric motor such as a capacitor. As the “control means”, when the accelerator position is OFF at the shift position SP and the catalyst temperature Tc is equal to or higher than the threshold value Tcref, the required braking power Pr * corresponding to the required braking torque Tr * is obtained from the input limit Win of the battery 50. The engine is configured to output a braking torque based on the required braking torque Tr * to the ring gear shaft 32a while driving the engine 22 independently (without engine braking) when the electric power is large (small absolute value) or more than the predetermined electric power Ws. 22 and the motors MG1 and MG2 are controlled, and when the required braking power Pr * is less than the predetermined power Ws, a braking torque based on the required braking torque Tr * is output to the ring gear shaft 32a as a drive shaft with a so-called engine brake. The engine 22 and the motors MG1, MG2 are controlled so as to travel When the medium temperature Tc is less than the threshold value Tcref, when the requested braking power Pr * is equal to or greater than the input limit Win of the battery 50, the engine 22 is operated independently and a braking torque based on the requested braking torque Tr * is output to the ring gear shaft 32a. When the engine 22 and the motors MG1 and MG2 are controlled so that the required braking power Pr * is less than the input limit Win of the battery 50, the required braking torque Tr * is applied to the ring gear shaft 32a as a drive shaft together with a so-called engine brake. It is not limited to controlling the engine 22 and the motors MG1, MG2 so that the vehicle travels by outputting a braking torque based on it, and when the shift position SP is at the S position, the catalyst temperature Tc is equal to or higher than the threshold value Tcref. Set the required braking torque Tr * according to ~ S6 When the catalyst temperature Tc is lower than the threshold value Tcref, the same required braking torque Tr * is set as when the shift position SP is the D position. When the required braking position has a shift position and the accelerator is off, when the temperature of the purification catalyst is equal to or higher than the lower limit temperature defined as the lower limit of the temperature range in which the purification catalyst is activated, the fuel injection of the internal combustion engine is stopped and power generation is performed. The motoring braking control for controlling the internal combustion engine, the generator, and the motor so as to travel with the required braking force required for the vehicle with the motoring of the internal combustion engine by the machine, and the required braking force with the fuel injection of the internal combustion engine Out of the driving braking control that controls the internal combustion engine, the generator, and the motor to run, the motoring braking control is superior. If the temperature of the purification catalyst is lower than the lower limit temperature, the driving braking control may be executed with priority given to the motoring braking control and the driving braking control.

  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 is applicable to the hybrid vehicle manufacturing industry.

  20,120 Hybrid vehicle, 22 engine, 24 engine electronic control unit (engine ECU), 24a CPU, 24b ROM, 24c RAM, 26 crankshaft, 28 damper, 30 power distribution integrated mechanism, 31 sun gear, 32 ring gear, 32a ring gear Shaft, 33 pinion gear, 34 carrier, 35 reduction gear, 40 motor electronic control unit (motor ECU), 41, 42 inverter, 43, 44 rotational position detection sensor, 50 battery, 51a voltage sensor, 51b current sensor, 51c temperature sensor , 52 battery electronic control unit (battery ECU), 54 power line, 60 gear mechanism, 62 differential gear, 63a, 63b driving wheel, 64a, 64b wheel, 70 electronic control for hybrid Control unit, 72 CPU, 74 ROM, 76 RAM, 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 throttle valve, 126 fuel injection valve, 128 intake valve, 130 spark plug, 132 piston, 134 purification device, 134a purification catalyst, 135a air-fuel ratio sensor, 135b oxygen sensor, 135c temperature sensor, 136, throttle motor, 138 ignition Coil, 140 Crank position sensor, 142 Water temperature sensor, 143 Pressure sensor, 144 Cam position sensor, 146 Throttle bar Bed position sensor, 148 an air flow meter, 149 temperature sensor, 150 a variable valve timing mechanism, MG1, MG2 motor.

Claims (4)

An internal combustion engine having a purification device having a purification catalyst for purifying exhaust gas in an exhaust system;
A generator capable of inputting and outputting power;
It is connected to three shafts, that is, a drive shaft coupled to an axle, an output shaft of the internal combustion engine, and a rotating shaft of the generator, and the remaining power is determined based on power input / output to / from any two of the three shafts. 3-axis power input / output means for inputting / outputting power to the shaft;
An electric motor capable of inputting and outputting power to the drive shaft;
Power storage means capable of exchanging electric power with the generator and the motor;
The lower limit of the temperature range in which the temperature of the purification catalyst is activated when the shift position is at the braking position where a large braking force is required when the accelerator is off compared to the normal driving position and the accelerator is off. The internal combustion engine and the generator so that the vehicle travels with the required braking force required for the vehicle with stop of fuel injection of the internal combustion engine and motoring of the internal combustion engine by the generator Motoring braking control for controlling the motor and the motor, and driving braking control for controlling the internal combustion engine, the generator and the motor so as to travel with the required braking force with fuel injection of the internal combustion engine. Priority is given to motoring braking control, and the motoring braking control is performed when the temperature of the purification catalyst is lower than the lower limit temperature. An accelerator-off time control means for performing preferentially the operation braking control of said operating brake control,
Equipped with a,
The accelerator-off-time control means is configured such that when the shift position is in the braking position and the accelerator is off, and when the temperature of the purification catalyst is equal to or higher than the lower limit temperature, the requested braking power corresponding to the requested braking force The autonomous driving braking control is executed when within the power range, and the motoring braking control is executed when the required braking power is outside the first power range, and the temperature of the purification catalyst is less than the lower limit temperature. Sometimes, when the required braking power is within a second power range that is wider than the first power range, the autonomous driving braking control is executed, and when the required braking power is outside the second power range, the motor Means for executing ring braking control;
Hybrid car. The hybrid vehicle according to claim 1 ,
The first power range and the second power range are power ranges that are determined as a range that travels by the required braking force by regenerative braking of the electric motor without motoring of the internal combustion engine.
Hybrid car. A hybrid vehicle according to claim 1 or 2 ,
The accelerator-off-time control means is configured such that when the shift position is at the braking position and the accelerator is off, the temperature of the purification catalyst is lower than the lower limit temperature, and the temperature of the purification catalyst is equal to or higher than the lower limit temperature. A means for setting the required braking force to a braking force smaller than
Hybrid car. An internal combustion engine having a purification device having a purification catalyst for purifying exhaust gas in an exhaust system, a generator capable of inputting and outputting power, a drive shaft connected to an axle, an output shaft of the internal combustion engine, and the generator A three-axis power input / output means connected to the three axes of the rotating shaft and inputting / outputting power to / from the remaining shaft based on power input / output to / from any two of the three axes; A control method for a hybrid vehicle comprising: an electric motor capable of inputting / outputting power; and an electric storage means capable of exchanging electric power with the electric generator and the electric motor,
The lower limit of the temperature range in which the temperature of the purification catalyst is activated when the shift position is at the braking position where a large braking force is required when the accelerator is off compared to the normal driving position and the accelerator is off. The internal combustion engine and the generator so that the vehicle travels with the required braking force required for the vehicle with stop of fuel injection of the internal combustion engine and motoring of the internal combustion engine by the generator Motoring braking control for controlling the motor and the motor, and driving braking control for controlling the internal combustion engine, the generator and the motor so as to travel with the required braking force with fuel injection of the internal combustion engine. Priority is given to motoring braking control, and the motoring braking control is performed when the temperature of the purification catalyst is lower than the lower limit temperature. Comprising: performing preferentially the operation braking control of said operating brake control,
In the step, when the shift position is in the braking position and the accelerator is off, the required braking power corresponding to the required braking force is within a first power range when the temperature of the purification catalyst is equal to or higher than the lower limit temperature. When the autonomous braking control is executed, the motoring braking control is executed when the required braking power is outside the first power range, and the required braking is performed when the temperature of the purification catalyst is less than the lower limit temperature. The autonomous driving braking control is executed when the power is within a second power range that is wider than the first power range, and the motoring braking control is performed when the required braking power is outside the second power range. Is the step to perform,
A control method for a hybrid vehicle.

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