JP2007216795A - Power output device, automobile mounted with the same and method for controlling power output device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress the deterioration of the purification function of a purification device installed in a hybrid car. <P>SOLUTION: When an S position is selected as a shift position, and an accelerator opening Acc is a value 0, and the oxygen occlusion of a purification device for purifying the exhaust gas of an engine is within the extent of below a threshold (S120), the motoring of the engine is performed at the target number of revolutions while fuel supply is stopped, and motoring control for controlling the engine and motors MG1 and MG2 is executed so that braking torque based on a request braking torque can be output to a driving shaft (S130 to 200), and when the oxygen occlusion exceeds the threshold, the target number of revolutions of the engine is set as the idle number of revolutions restricted in comparison with the case of motoring control (S210), and the engine is operated by the set target number of revolutions. Thus, the number of revolutions of the engine is restricted when the deterioration of the purification function of the exhaust gas of a purification device is predicted so that the quantity of oxygen to be supplied to the purification device can be reduced. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a power output device, an automobile equipped with the same, and a control method for the power output device.

Conventionally, as a power output device, one in which a first motor generator, an engine, and a second motor generator are connected to a sun gear, a carrier, and a ring gear of planetary gears has been proposed (see, for example, Patent Document 1). In this device, when the accelerator is turned off when the temperature of the purification device for purifying exhaust gas from the engine is equal to or higher than a predetermined temperature, the second motor generator is operated as a generator to obtain a braking force, and the fuel cut of the engine And the reduction of the purification function of the purification device is suppressed by suppressing the temperature rise of the purification device by increasing the engine speed by the first motor generator and supplying a large amount of exhaust gas to the purification device.
JP 2004-340102 A

  However, the purifying device sometimes stores oxygen to purify the exhaust gas. In the hybrid vehicle described in Patent Document 1, even when the temperature of the purifying device is lower than the set temperature, Depending on the occlusion state, the exhaust purification function may deteriorate. In addition, since the engine speed is related to the amount of air supplied to the purification device, it is desirable to consider the engine speed in order to suppress a reduction in the purification function of the purification device.

  This invention is made | formed in view of such a subject, and it aims at providing the hybrid vehicle which can suppress the fall of the purification function of a purification apparatus, and its control method.

  The present invention adopts the following means in order to achieve the above-mentioned object.

The power output apparatus of the present invention is
An internal combustion engine;
A purification means capable of storing oxygen and purifying the exhaust gas of the internal combustion engine;
Power generation means capable of motoring the internal combustion engine and capable of generating power using at least part of the power from the internal combustion engine;
An electric motor capable of outputting power to the drive shaft;
Power storage means capable of exchanging electric power with the power generation means and the electric motor,
A storage amount calculating means for calculating the oxygen storage amount of the purifying means;
Requested braking force setting means for setting a requested braking force to be output to the drive shaft;
When a braking force request is made, when the calculated oxygen storage amount is within a predetermined range, the target rotational speed of the internal combustion engine is set based on a predetermined constraint, and the fuel supply of the internal combustion engine is stopped. The internal combustion engine, the power generation means, and the motor are motored by the power generation means at the set target rotational speed and the braking force based on the set required braking force is output to the drive shaft. The first braking control is executed, and when the calculated oxygen storage amount exceeds a predetermined range, the target rotational speed of the internal combustion engine is set so as to be limited compared to that during the first braking control. A second braking system that operates the internal combustion engine at a target rotational speed and controls the internal combustion engine, the power generation means, and the motor so that a braking force based on the set required braking force is output to the drive shaft. And control means for executing,
It is equipped with.

  In this power output device, the oxygen storage amount of the purifying means is calculated, the required braking force to be output to the drive shaft is set, and when the braking force request is made, the calculated oxygen storage amount is within a predetermined range. Sometimes, the target rotational speed of the internal combustion engine is set based on a predetermined constraint, and the internal combustion engine is motored at the set target rotational speed in a state where the fuel supply of the internal combustion engine is stopped, and based on the set required braking force. When the first braking control for controlling the internal combustion engine, the power generation means, and the electric motor is performed so that the braking force is output to the drive shaft, and the calculated oxygen storage amount exceeds a predetermined range, the target rotational speed of the internal combustion engine Is set to be limited in comparison with that during the first braking control, and the internal combustion engine and the power generator are operated so that the internal combustion engine is operated at the set target rotational speed and the braking force based on the set required braking force is output to the drive shaft. Means and electricity Executing the second brake control for controlling the machine. As described above, when the oxygen storage amount of the purification device increases beyond the predetermined range during braking, the amount of oxygen supplied to the purification device is reduced by limiting the rotational speed of the internal combustion engine. Therefore, it is possible to suppress a decrease in the purification function of the purification device. Further, since the rotational speed of the internal combustion engine is changed based on the vehicle speed when the oxygen storage amount of the purifier is within a predetermined range, the uncomfortable feeling at the time of braking is reduced as compared with the case where the rotational speed of the internal combustion engine is decelerated without being changed. be able to.

  The power output apparatus of the present invention includes vehicle speed detecting means capable of detecting a vehicle speed, and the control means sets the target rotational speed of the internal combustion engine based on at least the detected vehicle speed as the predetermined constraint. It may be a means.

  In the power output apparatus of the present invention, the control means controls the electric motor so that the set required braking force is output to the drive shaft by power generation of the electric motor when executing the second braking control. The power storage unit may store at least part of the power generated by the motor. In this way, it is possible to give the operator a feeling of deceleration during braking of the vehicle by power generation by the electric motor.

  The power output apparatus according to the present invention sets an execution shift position from among a plurality of shift positions according to an operator's shift operation, and associates with the set execution shift position. Mode selection means that allows the operator to select execution of a sequential mode that performs control including the first braking control based on operating conditions including the control means, when the sequential mode is selected, The power storage means may be means for setting a target power storage amount smaller than normal. In the sequential mode, oxygen is easily stored in the purifier device by executing the first braking control, and the frequency of executing the second braking control is increased. Therefore, the braking force at the time of braking is covered by power generation by the motor. The frequency of storing the electric power generated in the storage means increases. Here, when the sequential mode is selected, the target power storage amount of the power storage means is made smaller than normal in preparation for braking, so that more power generated by the motor can be stored in the power storage means, and more second Braking control can be executed.

  In the power output apparatus of the present invention, the control means sets the target rotational speed to a predetermined low rotational speed or a value of zero when the target rotational speed of the internal combustion engine is set to be limited compared to that during the first braking control. It is good also as a means to set to. Here, the “predetermined low rotational speed” may be an idle rotational speed (for example, 600 rpm or 1000 rpm).

  In the power output apparatus of the present invention, the power generation means is connected to the output shaft of the internal combustion engine and the drive shaft, and drives at least part of the power from the internal combustion engine with input and output of power and power. It may be a power power input / output means that can output to the shaft. At this time, the electric power drive input / output means is connected to the three shafts of the output shaft of the internal combustion engine, the drive shaft and the rotary shaft, and the remaining power based on the power input / output to any two of the three shafts. It is good also as a means provided with the triaxial type | mold power input / output means which inputs / outputs motive power to a shaft, and the electric motor which can input / output motive power to the said rotating shaft.

  An automobile according to the present invention includes any one of the power output devices described above, and an axle is connected to the drive shaft. Since this power output device can suppress a reduction in the purification function of the purification device as described above, the same effect can be obtained in a vehicle equipped with this power output device.

The method for controlling the power output apparatus of the present invention includes:
An internal combustion engine; purification means capable of storing oxygen and purifying exhaust gas of the internal combustion engine; and power generation means capable of motoring the internal combustion engine and capable of generating electric power using at least part of the power from the internal combustion engine. A method for controlling a power output device comprising: an electric motor capable of outputting power to a drive shaft; and a power storage means capable of exchanging electric power with the power generation means and the electric motor,
Calculate the oxygen storage amount of the purification means,
When a braking force request is made, when the calculated oxygen storage amount is within a predetermined range, the target rotational speed of the internal combustion engine is set based on a predetermined constraint, and the fuel supply of the internal combustion engine is stopped. The internal combustion engine, the power generation means, and the motor so that the power generation means motors the internal combustion engine at a set target rotational speed and a braking force based on a required braking force to be output to the drive shaft is output to the drive shaft. The first braking control for controlling the electric motor is executed, and when the calculated oxygen storage amount exceeds a predetermined range, the target rotational speed of the internal combustion engine is limited and set as compared with that during the first braking control. The internal combustion engine is operated at the set target rotational speed, and the internal combustion engine, the power generation means, and the electric motor are controlled so that a braking force based on a required braking force to be output to the drive shaft is output to the drive shaft. It is intended to include performing a second brake control that.

  In this power output device control method, the oxygen storage amount of the purifying means is calculated, and when the braking force request is made, and the calculated oxygen storage amount is within a predetermined range, the internal combustion engine is based on a predetermined constraint. The target engine speed is set, and the internal combustion engine is motored at the set target engine speed while the fuel supply to the internal combustion engine is stopped, and the braking force based on the required braking force to be output to the drive shaft is output to the drive shaft. When the first braking control for controlling the internal combustion engine, the power generation means, and the electric motor is executed and the calculated oxygen storage amount exceeds a predetermined range, the target rotational speed of the internal combustion engine is set to the time of the first braking control. The internal combustion engine, the power generation means, and the electric motor are set so that the internal combustion engine is operated at the set target rotational speed and the braking force based on the required braking force to be output to the drive shaft is output to the drive shaft. Control Executing the second brake control that. As described above, when the oxygen storage amount of the purification device increases beyond the predetermined range during braking, the amount of oxygen supplied to the purification device is reduced by limiting the rotational speed of the internal combustion engine. Therefore, it is possible to suppress a decrease in the purification function of the purification device. Further, since the rotational speed of the internal combustion engine is changed based on the vehicle speed when the oxygen storage amount of the purifier is within a predetermined range, the uncomfortable feeling at the time of braking is reduced as compared with the case where the rotational speed of the internal combustion engine is decelerated without being changed. be able to. In this method for controlling the power output apparatus, various aspects of the power output apparatus described above may be adopted, and steps for realizing each function of the power output apparatus described above may be added. .

  Next, the best mode for carrying out the present invention will be described using examples.

  FIG. 1 is a configuration diagram showing an outline of the configuration of a hybrid vehicle 20 according to an embodiment of the present invention. As shown in the figure, the hybrid vehicle 20 of the embodiment includes an engine 22, a three-shaft power distribution / integration mechanism 30 connected to a crankshaft 26 as an output shaft of the engine 22 via a damper 28, and power distribution / integration. A motor MG1 capable of generating electricity connected to the mechanism 30, a reduction gear 35 attached to a ring gear shaft 32a as a drive shaft connected to the power distribution and integration mechanism 30, a motor MG2 connected to the reduction gear 35, And a hybrid electronic control unit 70 for controlling the entire power output apparatus.

The engine 22 is an internal combustion engine that outputs power using a hydrocarbon-based fuel such as gasoline or light oil, and an engine electronic control unit (hereinafter referred to as an engine ECU) that receives signals from various sensors that detect the operating state of the engine 22. ) 24 is subjected to operation control such as fuel injection control, ignition control, intake air amount adjustment control and the like. In the engine ECU 24, signals from various sensors that detect the state of the engine 22, for example, a signal from an air flow meter 29 provided in the intake pipe 27 of the engine 22, and an air-fuel ratio provided upstream of the purifier 37. An air-fuel ratio AF from the sensor 38, an oxygen signal from an oxygen sensor 39 provided on the downstream side of the purification device 37, and the like are input via an input port. Further, the engine ECU 24 communicates 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 transmits data on the operation state of the engine 22 as necessary for the hybrid. Output to the electronic control unit 70. Exhaust gas from the engine 22 is discharged to the outside air through a purification device (three-way catalyst) 37. The purification device 37 is composed of an oxidation catalyst such as platinum (Pt) or palladium (Pd), a reduction catalyst such as rhodium (Rh), a co-catalyst such as ceria (CeO ₂ ), etc., and can store oxygen. It has become. This purification device 37 purifies carbon monoxide (CO) and hydrocarbons (HC) contained in the exhaust gas into water (H ₂ O) and carbon dioxide (CO ₂ ) by the action of an oxidation catalyst, and nitrogen contained in the exhaust gas. The oxide (NOx) is purified to nitrogen (N ₂ ) or oxygen (O ₂ ) by the action of the reduction catalyst.

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

  The hybrid electronic control unit 70 is configured as a microprocessor centered on the CPU 72, and in addition to the CPU 72, a ROM 74 for storing processing programs, a RAM 76 for temporarily storing data, an input / output port and communication not shown. And a port. The hybrid electronic control unit 70 includes an ignition signal from an ignition switch 80, a shift position SP from a shift position sensor 82 that detects the operation position of the shift lever 81, and an accelerator pedal position sensor 84 that detects the amount of depression of the accelerator pedal 83. The accelerator 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, in addition to the P position used during parking, the R position for backward travel, the neutral N position, the normal D position for forward travel, etc. A sequential shift position (S position), an upshift instruction position, and a downshift instruction position are prepared. When the D position is selected as the shift position SP, the hybrid vehicle 20 of the embodiment is controlled to drive the engine 22 efficiently. On the other hand, when the S position is selected as the shift position SP, it is possible to execute a sequential mode in which the change in the rotational speed of the engine 22 with respect to the vehicle speed V is changed to, for example, six stages (SP1 to SP6). In the embodiment, when the shift lever 81 is set to the S position by the driver, the sequential mode is executed. For example, when the shift position SP is in the fifth stage, the shift position sensor 82 indicates that the shift position SP = SP5. Is detected. Thereafter, when the shift lever 81 is set to the upshift instruction position, the shift position SP is raised by one step (upshifted). On the other hand, when the shift lever 81 is set to the downshift instruction position, the shift position SP is lowered by one step (downshifted). At this time, the shift position sensor 82 outputs the current shift position SP according to the operation of the shift lever 81. As described above, when the operator performs the upshift and downshift operations of the shift lever 81, the rotational speed of the engine 22 is changed by adjusting the torque output from the motor MG1. Thus, it is possible to give the operator a feeling of driving similar to the feeling of shifting in a vehicle equipped with this manual transmission.

  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 configured as described above, particularly the operation when the sequential mode is selected during traveling and the accelerator pedal 83 is depressed by the operator will be described. FIG. 2 is a flowchart illustrating an example of an accelerator-off time control routine executed by the hybrid electronic control unit 70 of the hybrid vehicle 20 according to the embodiment. This routine is performed every predetermined time (for example, every several msec) when the shift lever 81 is set to the S position and the sequential mode is selected and when the accelerator pedal 83 is not depressed during traveling. Repeatedly executed.

  When the accelerator off-time control routine is executed, the CPU 72 of the hybrid electronic control unit 70 firstly shifts the vehicle speed V from the vehicle speed sensor 88, the rotational speeds Nm1, Nm2 of the motors MG1, MG2, and the shift position sensor 82. Processing for inputting data necessary for control, such as SP, input / output limits Win and Wout of the battery 50, and the oxygen storage amount OS of the purification device 37, is executed (step S100). Here, the rotational speeds Nm1 and Nm2 of the motors MG1 and MG2 are input from the motor ECU 40 by communication from those calculated based on the rotational positions of the rotors of the motors MG1 and MG2 detected by the rotational position detection sensors 43 and 44. To do. The input / output limits Win and Wout of the battery 50 are set based on the battery temperature Tb of the battery 50 detected by the temperature sensor 51 and the remaining capacity (SOC) of the battery 50 from the battery ECU 52 by communication. To do. The input / output limits Win and Wout of the battery 50 are set to 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 are set 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. Further, the oxygen storage amount OS of the purification device 37 is an integrated value of the amount of oxygen supplied to the purification device 37, and after the hybrid vehicle 20 is started, a signal from an air flow meter 29 provided in the intake pipe 27 of the engine 22. The oxygen amount is obtained based on the intake air amount and the fuel injection amount obtained by the above, and is calculated as a value obtained by integrating the oxygen amount, and is input from the engine ECU 24 by communication. In addition, the oxygen storage amount OS is corrected to a value of 0, for example, by resetting the lean signal and the rich signal from the oxygen sensor 39, and is stored in a battery-backed flash memory (not shown) of the engine ECU 24. Remembered. The oxygen storage amount OS may be obtained from the oxygen amount calculated based on the engine speed, the throttle opening, and the like.

  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. 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 braking torque setting map. And the corresponding required braking torque Tr * is derived and set from the stored map. FIG. 3 shows an example of the required braking torque setting map. In this required braking torque setting map, the required braking torque Tr * is determined to increase as the vehicle speed V increases, and to increase as the shift position SP decreases from SP6 to SP1.

  When the required braking torque Tr * is set, it is determined whether or not the input oxygen storage amount OS is equal to or less than the threshold value OSref (step S120). This threshold value OSref is empirically determined as a value of the oxygen storage amount OS that is less than the maximum storage amount that does not deteriorate the exhaust purification function of the purification device 37. Here, when the oxygen storage amount OS reaches a value close to the maximum storage amount, the purifying device 37 cannot store any more oxygen, so that the NOx reduction function decreases. Here, it is determined whether or not the exhaust purification function of the purification device 37 is lowered. When it is determined that the oxygen storage amount OS is equal to or less than the threshold value OSref, it is assumed that the exhaust purification function does not deteriorate even when oxygen-containing air is supplied to the purification device 37. The motor MG1 is forcibly motored at a rotational speed equal to or higher than Nemin, and the engine 22 and the motors MG1 and MG2 are configured so that a braking torque based on the set required braking torque Tr * is output to the ring gear shaft 32a as a drive shaft. Execute motoring control to control. Specifically, the lower limit rotation speed Nemin of the engine 22 is set based on the shift position SP and the vehicle speed V (step S130). In this embodiment, the relationship between the shift position SP from SP1 to SP6, the vehicle speed V, and the lower limit rotation speed Nemin of the engine 22 is determined in advance and stored in the ROM 74 as a lower limit rotation speed setting map for selecting the S position. When the shift position SP and the vehicle speed V are given, the lower limit rotational speed Nemin of the corresponding engine 22 is derived from this map and set. An example of a lower limit rotational speed setting map used when selecting the S position is shown in FIG. In this map, the lower limit rotational speed Nemin tends to increase as the vehicle speed increases, so that the lower limit rotational speed Nemin is a change in the rotational speed of the engine 22 approximate to a vehicle equipped with a manual transmission, and the shift position SP. Is set to tend to decrease as S1 increases from S1 to S6.

  When the lower limit rotational speed Nemin of the engine 22 is thus set, the lower limit rotational speed Nemin is set to the target rotational speed Ne * of the engine 22 (step S140), and a fuel cut command is transmitted to the engine ECU 24 (step S150). Next, using the set target rotational speed Ne *, the rotational speed Nr (Nm2 / Gr) of the ring gear shaft 32a, and the gear ratio ρ of the power distribution and integration mechanism 30, the target rotational speed Nm1 of the motor MG1 is given by the following equation (1). * Is calculated and a torque command Tm1 * of the motor MG1 is calculated by equation (2) based on the calculated target rotational speed Nm1 * and the current rotational speed Nm1 (step S160). Here, Expression (1) is a dynamic relational expression for the rotating element of the power distribution and integration mechanism 30. FIG. 5 is a collinear diagram showing a dynamic relationship between the number of rotations and torque in the rotating elements of the power distribution and integration mechanism 30. In the figure, the left S-axis indicates the rotation speed of the sun gear 31 that is the rotation speed Nm1 of the motor MG1, the C-axis indicates the rotation speed of the carrier 34 that is the rotation speed Ne of the engine 22, and the R-axis indicates the rotation speed of the motor MG2. The rotational speed Nr of the ring gear 32 obtained by 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. The two thick arrows on the R axis indicate that the torque Tm1 output from the motor MG1 acts on the ring gear shaft 32a and the torque Tm2 output from the motor MG2 acts on the ring gear shaft 32a via the reduction gear 35. Torque. Expression (2) is a relational expression in feedback control for rotating the motor MG1 at the target rotational speed Nm1 *. In Expression (2), “k1” in the second term on the right side is a gain of a proportional term. “K2” in the third term on the right side is the gain of the integral term.

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

  When the target rotational speed Nm1 * and the torque command Tm1 * of the motor MG1 are thus calculated, the input / output limits Win and Wout of the battery 50 and the calculated torque command Tm1 * of the motor MG1 are multiplied by the current rotational speed Nm1 of the motor MG1. Torque limits Tmin and Tmax as upper and lower limits of the torque that may be output from the motor MG2 by dividing the deviation from the obtained power consumption (generated power) of the motor MG1 by the rotational speed Nm2 of the motor MG2 is expressed by the following equation (3). And the temporary motor torque Tm2tmp as a torque to be output from the motor MG2 using the required braking torque Tr *, the torque command Tm1 *, and the gear ratio ρ of the power distribution and integration mechanism 30 (step S170). Is calculated by equation (5) (step S180), and the calculated torque limits Tmin, Tma are calculated. In setting the torque command Tm2 * of the motor MG2 limits the tentative motor torque Tm2tmp (step S190). By setting the torque command Tm2 * of the motor MG2 in this way, the required braking torque Tr * output to the ring gear shaft 32a as the drive shaft is limited to a torque within the range of the input / output limits Win and Wout of the battery 50. Can be set. Equation (5) can be easily derived from the collinear diagram of FIG. 5 described above.

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

  When the torque commands Tm1 * and Tm2 * for the motors MG1 and MG2 are set in this manner, the set torque commands Tm1 * and Tm2 * are transmitted to the motor ECU 40 (step S200), and the drive control routine is terminated. The engine ECU 24 that has received the fuel cut command transmitted in step S150 stops fuel injection to the engine 22. 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. As described above, when the purifying device 37 has a margin for storing oxygen when the accelerator is off in the sequential mode, the engine 22 in the fuel cut state is forced by the motor MG1 at the lower limit rotational speed Nemin corresponding to the shift position SP and the vehicle speed V. Thus, by motoring, a so-called engine brake can be applied to the ring gear shaft 32a and a braking torque generated by the power generation of the motor MG2 can be applied (see FIG. 5). At this time, a part of the electric power generated by the motor MG2 is consumed by driving the motor MG1, and the rest is stored in the battery 50.

  On the other hand, if it is determined in step S130 that the oxygen storage amount OS is not equal to or less than the threshold value OSref, that is, the oxygen storage amount OS exceeds the threshold value OSref, the exhaust gas purifying function is provided when air containing oxygen is supplied to the purification device 37. Is set to a target engine speed Ne * of the engine 22 that is set to an idling engine speed Neid limited to a lower limit engine speed Nemin at an arbitrary shift position SP, and a target torque Te * of the engine 22 is set to a value 0. Is set (step S210). In other words, the engine 22 is idled so that the amount of air supplied to the purification device 37 per unit time is reduced and air containing oxygen is not supplied to the purification device 37. For example, 600 rpm or 1000 rpm can be used as the idle rotation speed Neidl. At this time, the fuel storage amount of the engine 22 may be set to the rich side to reduce the oxygen storage amount OS of the purification device 37.

  Then, the set target rotational speed Ne * and target torque Te * of the engine 22 are transmitted to the engine ECU 24 (step S220), and the target rotational speed Nm1 * of the motor MG1 that becomes the target rotational speed Ne * in step S160. Torque command Tm1 * of motor MG1 is calculated, torque limits Tmin and Tmax are calculated as upper and lower limits of torque in consideration of input / output limits Win and Wout of battery 50 in step S170, and output from motor MG2 in step S180. The temporary motor torque Tm2tmp as the power torque is calculated, the torque command Tm2 * of the motor MG2 is set as a value obtained by limiting the temporary motor torque Tm2tmp with the torque limits Tmin and Tmax in step S190, and the torque commands Tm1 * and Tm2 are set in step S200. * Send a drive control routine To end the. The engine ECU 24 that has received the target rotational speed Ne * and the target torque Te * transmitted in step S220 causes the engine 22 to operate at the operating point indicated by the target rotational speed Ne * and the target torque Te *. Control such as fuel injection control and ignition control at 22 is performed. 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. As described above, when the purifying device 37 cannot afford to store oxygen when the accelerator is off in the sequential mode, the engine 22 is idling and a braking torque based on the required braking torque Tr * is output from the motor MG2 to the ring gear shaft 32a. The motor MG2 is controlled as described above. At this time, the so-called engine brake does not act on the ring gear shaft 32a, and the electric power generated by the motor MG2 is stored in the battery 50 without being consumed by the motor MG1.

  According to the hybrid vehicle 20 of the present embodiment described in detail above, when the oxygen storage amount OS of the purification device 37 is within the threshold OSref or less when the accelerator in the sequential mode is off, it is based on the vehicle speed V and the shift position SP. The target rotational speed Ne * of the engine 22 is set, and the engine 22 is motored at the set target rotational speed Ne * with the fuel supply of the engine 22 stopped, and braking based on the set required braking torque Tr *. When the motoring control for controlling the engine 22 and the motors MG1 and MG2 is executed so that torque is output to the ring gear shaft 32a as the drive shaft, and the oxygen storage amount OS exceeds the threshold value OSref, the target rotation of the engine 22 is performed. The number Ne * is set to the idle rotation speed Neid, which is limited compared to the motoring control. And controls the engine 22 and the motor MG1, MG2 so that the braking torque based on the set braking torque demand Tr * with operating the engine 22 at the target rotation speed Ne * that this setting is output to the ring gear shaft 32a. As described above, when the oxygen storage amount OS of the purification device 37 increases beyond the threshold value OSref, the amount of oxygen supplied to the purification device 37 is reduced by limiting the rotational speed of the engine 22. Therefore, it is possible to suppress a reduction in the purification function of the purification device 37 due to the oxygen storage amount OS. Further, when the oxygen storage amount OS of the purification device 37 is within the range of the threshold value OSref or less, the engine 22 is motored by the motor MG1 based on the vehicle speed V to change the rotation speed of the engine 22. It is possible to reduce the uncomfortable feeling at the time of braking compared to the case where the vehicle is decelerated without being changed. Further, the motor MG2 is driven and controlled so that the required braking torque Tr * is output to the ring gear shaft 32a by the power generation of the motor MG2, and at least a part of the power generated by the motor MG2 is stored in the battery 50. This power generation can give the operator a feeling of deceleration during braking of the vehicle.

  In addition, this invention is not limited to the Example mentioned above at all, and as long as it belongs to the technical scope of this invention, it cannot be overemphasized that it can implement with a various aspect.

  For example, in the above-described embodiment, when the oxygen storage amount OS of the purification device 37 exceeds the threshold value OSref when the accelerator in the sequential mode is off, the idle speed Neidl limited to the lower limit speed Nemin at an arbitrary shift position SP. However, the present invention is not limited to this, and may be set to a rotational speed limited (smaller) than the lower limit rotational speed Nemin corresponding to each shift position SP. Even in this case, it is possible to reduce the amount of oxygen supplied to the purification device 37 as compared with the motoring control, and it is possible to suppress a reduction in the purification function of the purification device 37. Alternatively, the target rotational speed Ne * of the engine 22 may be set to 0, that is, the engine 22 may be stopped. Even in this case, it is possible to reduce the amount of oxygen supplied to the purifying device 37 and to suppress a decrease in the purifying function of the purifying device 37.

  In the above-described embodiment, the accelerator-off-time control routine executed when the accelerator is off in the sequential mode has been described. For example, when the shift lever 81 is set to the D position, power is efficiently output from the engine 22. A drive control routine (not shown) for controlling the engine 22 and the motors MG1, MG2 is executed, and when the shift lever 81 is set to the S position, the above-mentioned shift feeling is created in a vehicle equipped with a stepped manual transmission. A sequential mode control routine (not shown) including an accelerator off time control routine is executed so that the target remaining capacity SOC * of the battery 50 is smaller in the sequential mode control routine than in the drive control routine. It may be set. Specifically, in the drive control routine, a predetermined value S1 is set for the target remaining capacity SOC *, and the charge / discharge required power to be charged / discharged to / from the battery 50 based on the set target remaining capacity SOC * and the remaining capacity SOC. Set Pb *. The charge / discharge required power Pb * is stored in the ROM 74 as a charge / discharge required power setting map by predetermining the relationship between the remaining capacity (SOC) of the battery 50, the charge / discharge required power Pb *, and the shift position SP. When the remaining capacity (SOC) of the battery 50 and the shift position SP are given, the corresponding charge / discharge required power Pb * is derived and set from the stored map. An example of the charge / discharge required power setting map is shown in FIG. In the example of FIG. 6, when the shift position SP is the D position, the charge / discharge required power Pb * is 0 in the range from the threshold value Sref1 to the threshold value Sref2 where the remaining capacity (SOC) of the battery 50 includes the target remaining capacity SOC *. Is set, charging power is set in a range less than the threshold value Sref1, and discharging power is set in a range equal to or higher than the threshold value Sref2 (see the one-dot chain line in the figure). As this target remaining capacity SOC *, for example, 50%, 60%, 70% or the like can be used, and as the threshold value S1, a value about 5%, 10% or 15% smaller than the target remaining capacity SOC * can be used. As the threshold value S2, a value about 5%, 10% or 15% larger than the target remaining capacity SOC * can be used. On the other hand, when the shift position SP is the S position, the charge / discharge required power Pb * is determined from a threshold value Sref3 including a predetermined value S2 as a target remaining capacity SOC * in which the remaining capacity (SOC) of the battery 50 is smaller than the predetermined value S1. The value 0 is set in the range of the threshold Sref4, the power for charging is set in the range less than the threshold Sref3, and the power for discharging is set above the threshold Sref4 (see the solid line in the figure). As the predetermined value S2 of the target remaining capacity SOC *, for example, 20%, 30%, 40% or the like can be used. As the threshold value Sref3, a value that is about 5%, 10%, or 15% smaller than the target remaining capacity SOC *. As the threshold value Sref4, a value about 5%, 10%, or 15% larger than the target remaining capacity SOC * can be used. In this way, when the sequential mode is selected by the operator by setting the shift lever 81 to the S position, a large range in which the battery 50 can be charged is secured. Then, the engine 22 is operated so that the set charge / discharge required power Pb * is output from the engine 22. In the sequential mode, the frequency of motoring the engine 22 by the motor MG1 is high, oxygen is easily stored in the purifier 37, and when the oxygen storage amount OS exceeds the threshold value OSref, the braking force during braking is covered by power generation by the motor MG2. As a result, the frequency with which the electric power generated by the motor MG2 is stored in the battery 50 is increased. Here, when the sequential mode is selected, power is generated by the motor MG2 in order to set the target remaining capacity SOC * of the battery 50 to be smaller than normal in preparation for braking when the oxygen storage amount OS exceeds the threshold value OSref. Therefore, it is possible to store more electric power in the battery 50 and to generate power by the motor MG2 at a higher frequency.

  In the above-described embodiment, when the oxygen storage amount OS of the purifying device 37 exceeds the threshold value OSref when the accelerator in the sequential mode is off, the target rotational speed Ne * of the engine 22 that is more limited than in the motoring control is set. However, in addition to this, the throttle opening of the engine 22 may be limited to be small. By so doing, the amount of air supplied to the purification device 37 is further limited, so that the reduction in the purification function of the purification device 37 can be further suppressed.

  In the above-described embodiment, the processing when the engine 22 is motored by the motor MG1 when traveling in the sequential mode has been described. However, the processing is not limited to the case of traveling using the sequential shift. When the brake position (B position) that applies a braking force larger than the D position to the driving wheels 63a and 63b is selected as the shift position SP, any motoring of the engine 22 by the motor MG1 with power consumption is performed. It may be applied to the case.

  In the above-described embodiment, the case where the accelerator opening Acc in the sequential mode is 0 has been described. However, the case where the brake pedal 85 is depressed may be considered. That is, when the accelerator opening Acc is 0 and the brake pedal 85 is depressed, the required braking torque Tr * may be set according to the depression amount of the brake pedal. Further, when all of the required braking torque Tr * cannot be output from the motor MG2 due to the input / output restrictions Win and Wout of the battery 50, a brake actuator (not shown) may be operated to satisfy the required braking torque Tr * with a hydraulic brake. .

  In the above-described 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. It may be connected to an axle (an axle connected to the wheels 64a and 64b in FIG. 7) different from the axle to which the shaft 32a is connected (the axle to which the drive wheels 63a and 63b are connected).

  In the embodiment described above, the power of the engine 22 is output to the ring gear shaft 32a as the drive shaft connected to the drive wheels 63a and 63b via the power distribution and integration mechanism 30, but the hybrid of the modified example of FIG. As illustrated in the automobile 220, the engine 22 includes an inner rotor 232 connected to the crankshaft 26 of the engine 22 and an outer rotor 234 connected to a drive shaft that outputs power to the drive wheels 63a and 63b. It is good also as what is provided with the counter-rotor electric motor 230 which transmits a part of these to a drive shaft and converts the remaining motive power into electric power.

1 is a configuration diagram showing an outline of the configuration of a hybrid vehicle 20 equipped with a power output device as one embodiment of the present invention. 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 map for a minimum rotation speed setting. FIG. 4 is an explanatory diagram showing an example of a collinear diagram for dynamically explaining rotational elements of a power distribution and integration mechanism 30; It is explanatory drawing which shows an example of the map for charging / discharging request | requirement electric power setting. FIG. 11 is a configuration diagram showing an outline of a configuration of a hybrid vehicle 120 according to a modification. FIG. 11 is a configuration diagram showing an outline of a configuration of a hybrid vehicle 220 of a modified example.

Explanation of symbols

  20, 120, 220 Hybrid vehicle, 22 engine, 24 engine electronic control unit (engine ECU), 26 crankshaft, 27 intake pipe, 28 damper, 29 air flow meter, 30 power distribution integration mechanism, 31 sun gear, 32 ring gear, 32a Ring gear shaft, 33 pinion gear, 34 carrier, 35 reduction gear, 37 purification device, 38 air-fuel ratio sensor, 39 oxygen sensor, 40 motor electronic control unit (motor ECU), 41, 42 inverter, 43, 44 rotational position detection sensor, 50 battery, 51 temperature sensor, 52 battery electronic control unit (battery ECU), 54 power line, 60 gear mechanism, 62 differential gear, 63a, 63b driving wheel, 64a, 64b wheel, 70 hybrid Electronic 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, 230 pair rotor motor, 232 inner rotor 234 outer rotor, MG1, MG2 motor.

Claims (9)

An internal combustion engine;
A purification means capable of storing oxygen and purifying the exhaust gas of the internal combustion engine;
Power generation means capable of motoring the internal combustion engine and capable of generating power using at least part of the power from the internal combustion engine;
An electric motor capable of outputting power to the drive shaft;
Power storage means capable of exchanging electric power with the power generation means and the electric motor,
A storage amount calculating means for calculating the oxygen storage amount of the purifying means;
Requested braking force setting means for setting a requested braking force to be output to the drive shaft;
When a braking force request is made, when the calculated oxygen storage amount is within a predetermined range, the target rotational speed of the internal combustion engine is set based on a predetermined constraint, and the fuel supply of the internal combustion engine is stopped. The internal combustion engine, the power generation means, and the motor are motored by the power generation means at the set target rotational speed and the braking force based on the set required braking force is output to the drive shaft. The first braking control is executed, and when the calculated oxygen storage amount exceeds a predetermined range, the target rotational speed of the internal combustion engine is set so as to be limited compared to that during the first braking control. A second braking system that operates the internal combustion engine at a target rotational speed and controls the internal combustion engine, the power generation means, and the motor so that a braking force based on the set required braking force is output to the drive shaft. And control means for executing,
Power output device with The power output device according to claim 1,
Vehicle speed detecting means capable of detecting the vehicle speed,
The control means is means for setting a target rotational speed of the internal combustion engine based on at least the detected vehicle speed as the predetermined constraint.
Power output device.   The control means controls the electric motor so that the set required braking force is output to the drive shaft by the electric power generation of the electric motor when executing the second braking control, and the electric power generated by the electric motor The power output apparatus according to claim 1, wherein at least a part of the power is stored in the power storage unit. The execution shift position is set from among a plurality of shift positions in accordance with the shift operation of the operator, and based on the operation condition including the target rotational speed of the internal combustion engine associated with the set execution shift position. A mode selection unit that allows the operator to select execution of a sequential mode for performing control including first braking control;
4. The power output apparatus according to claim 1, wherein when the sequential mode is selected, the control unit is a unit that sets a target power storage amount of the power storage unit to be smaller than normal. 5.   The control means is means for setting the target rotational speed to a predetermined low rotational speed or a value of zero when the target rotational speed of the internal combustion engine is set to be limited as compared with that during the first braking control. Item 5. The power output apparatus according to any one of Items 1 to 4.   The power generation means is connected to the output shaft of the internal combustion engine and the drive shaft, and is equipped with electric power / power input capable of outputting at least part of the power from the internal combustion engine to the drive shaft with input / output of electric power and power. The power output apparatus according to any one of claims 1 to 5, which is an output means.   The power power input / output means is connected to the three shafts of the output shaft of the internal combustion engine, the drive shaft, and the rotating shaft, and power is supplied to the remaining shaft based on the power input / output to any two of the three shafts. The power output apparatus according to claim 6, comprising: a three-axis power input / output unit that inputs / outputs power; and an electric motor capable of inputting / outputting power to / from the rotary shaft.   An automobile on which the power output device according to claim 1 is mounted and an axle is connected to the drive shaft. An internal combustion engine; purification means capable of storing oxygen and purifying exhaust gas of the internal combustion engine; and power generation means capable of motoring the internal combustion engine and capable of generating electric power using at least part of the power from the internal combustion engine. A method for controlling a power output device comprising: an electric motor capable of outputting power to a drive shaft; and a power storage means capable of exchanging electric power with the power generation means and the electric motor,
Calculate the oxygen storage amount of the purification means,
When a braking force request is made, when the calculated oxygen storage amount is within a predetermined range, the target rotational speed of the internal combustion engine is set based on a predetermined constraint, and the fuel supply of the internal combustion engine is stopped. The internal combustion engine, the power generation means, and the motor so that the power generation means motors the internal combustion engine at a set target rotational speed and a braking force based on a required braking force to be output to the drive shaft is output to the drive shaft. The first braking control for controlling the electric motor is executed, and when the calculated oxygen storage amount exceeds a predetermined range, the target rotational speed of the internal combustion engine is limited and set as compared with that during the first braking control. The internal combustion engine is operated at the set target rotational speed, and the internal combustion engine, the power generation means, and the electric motor are controlled so that a braking force based on a required braking force to be output to the drive shaft is output to the drive shaft. Executing the second brake control that,
Control method of power output device.

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