JP2007168470A - Hybrid vehicle, and its control method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To well suppress deterioration of catalyst for purifying exhaust gas by appropriately increasing a fuel supply quantity to an internal combustion engine. <P>SOLUTION: A hybrid car 20 sets a tentative limit value Win0 fixing a relationship with a map for setting a first and a second OT quantity increase coefficient as an input limit Win of a battery 50 and a quantity increase restriction of a fuel injection quantity to an engine 22 so as to adjust temperatures of an exhaust purifying catalyst on the basis of a vehicle speed V indicating the traveling state (step S220), and controls the engine 22, and motors MG1, MG2 so as to output a driving force based on a set requirement torque Tr<SP>*</SP>as well as operates the engine 22 with the increase in quantity of the fuel injection quantity according to the map for setting a first and second OT quantity increase coefficient set on the basis of the input limit Win and the tentative limit value Win0, when prohibiting fuel cut in response to a determination result whether the fuel cut should be prohibited or not on the basis of the input limit Win. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

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

Conventionally, as an example of a hybrid vehicle, one in which a motor generator is disposed between a torque converter that transmits power of an internal combustion engine to a drive shaft and an automatic transmission is known (for example, see Patent Document 1). In this hybrid vehicle, when it is determined that the temperature of the catalyst is higher than a predetermined determination reference value, the internal combustion engine is to suppress deterioration of the catalyst due to exposure to a lean atmosphere at a high temperature. Control for suppressing the fuel cut is executed. That is, in this hybrid vehicle, when the catalyst is in a high temperature state, the fuel cut is prohibited even if a deceleration request based on the accelerator off or the like is made under a predetermined condition, to compensate for the decrease in the deceleration accompanying the prohibition of the fuel cut. A regenerative braking force is generated by the motor generator, and the regenerative power is stored in a power storage device such as a secondary battery. Further, in this hybrid vehicle, when a deceleration request is made based on the accelerator off or the like when the catalyst is in a high temperature state, the regenerative power by the motor generator may exceed the allowable charging power that is the allowable power for charging the power storage device. If there is, the required braking force is generated by the hydraulic brake instead of the regenerative braking force by the motor generator. Conventionally, as an example of a hybrid vehicle, in order to suppress deterioration of an exhaust gas purification catalyst that is mainly in a high temperature state by being exposed to a lean atmosphere, when the engine is stopped due to intermittent operation of the engine or the like. In addition, after performing a fuel increasing process for increasing the amount of fuel supplied to the combustion chamber as compared with the conventional state, a process for stopping the fuel supply is known (see, for example, Patent Document 2). ).
JP 2003-207043 A JP 2004-176710 A

  As described above, in the hybrid vehicle, when there is a possibility that the regenerative power exceeds the allowable charging power of the power storage device when the deceleration request is made, the braking force required by the hydraulic brake is used instead of the regenerative braking force by the motor generator. If generated, fuel cut in the internal combustion engine can be prohibited in order to suppress the deterioration of the catalyst even in a high temperature state. However, it is not easy to quickly generate the deceleration force based on accelerator-off etc. by the hydraulic brake, and the control becomes complicated, so if there is a possibility that the regenerative power exceeds the allowable charging power, cut the fuel as much as possible. It is preferable to allow and obtain the braking force by the engine brake. Thus, in order to be able to suppress the deterioration of the catalyst even if the prohibition of fuel cut is canceled from the relationship with the allowable charging power of the power storage device, the prohibition of fuel cut is canceled based on the allowable charging power. In addition, the temperature of the catalyst may be adjusted by increasing the fuel supply amount. However, the timing to cancel the prohibition of fuel cut based on the chargeable power varies depending on various conditions.If the amount of fuel supply is simply increased, the relationship with the chargeable power of the power storage device When the prohibition of fuel cut is canceled, there is a possibility that the catalyst cannot be kept in a state in which deterioration can be suppressed. On the other hand, it is necessary to prevent the fuel supply amount from being increased excessively while prohibiting fuel cut from the viewpoint of suppressing deterioration of fuel consumption.

  Accordingly, an object of the hybrid vehicle and the control method thereof according to the present invention is to satisfactorily suppress the deterioration of the exhaust gas purification catalyst by appropriately increasing the amount of fuel supplied to the internal combustion engine. In addition, the hybrid vehicle and the control method thereof according to the present invention suppress the deterioration of fuel consumption by increasing the fuel supply amount more appropriately when the fuel supply amount is increased to suppress the deterioration of the exhaust gas purification catalyst. One of the purposes is to do.

  The hybrid vehicle and the control method thereof according to the present invention employ the following means in order to achieve at least a part of the above-described object.

The hybrid vehicle according to the present invention
An internal combustion engine;
Purification means including a catalyst for purifying exhaust gas discharged from the internal combustion engine;
Power power input / output means connected to the first axle as one of the axles and the output shaft of the internal combustion engine and capable of inputting / outputting power to / from the first axle and the output shaft with input / output of power and power When,
An electric motor capable of inputting / outputting power to / from a second axle that is either the first axle or an axle different from the first axle;
Power storage means capable of exchanging power between the power drive input / output means and the electric motor;
Charge allowable power setting means for setting charge allowable power that is power allowed for charging of the power storage means based on the state of the power storage means;
Fuel supply stop determination means for determining whether or not to stop the fuel supply to the internal combustion engine based on the set allowable charge power;
Traveling state acquisition means for acquiring the traveling state of the vehicle;
Required driving force setting means for setting required driving force required for traveling;
Fuel increase relationship setting means for setting a fuel increase relationship that is a relationship between the allowable charging power and the increase restriction of the fuel supply amount to the internal combustion engine for adjusting the temperature of the catalyst based on the acquired traveling state. When,
The internal combustion engine is operated with an increase in the fuel supply amount in accordance with an increase restriction determined from the set charge allowable power and the set fuel increase relationship according to the determination result by the fuel supply stop determination means. And a control means for controlling the internal combustion engine, the power power input / output means and the electric motor so that a driving force based on the set required driving force is output.
Is provided.

  In this hybrid vehicle, there is a relationship between the allowable charging power set as the allowable power for charging the power storage means based on the traveling state and the increase in the amount of fuel supplied to the internal combustion engine for adjusting the temperature of the catalyst. A fuel increase relationship is set. Then, it is determined from the set charge allowable power and the set fuel increase relationship according to the determination result of whether or not to stop the fuel supply based on the charge allowable power set based on the state of the power storage means. The internal combustion engine, the power power input / output means, and the electric motor so that the internal combustion engine is operated with an increase in the fuel supply amount in accordance with the increase restriction, and a driving force based on the required driving force required for traveling is output. Is controlled. Thus, if the fuel increase relationship is set based on the running state of the vehicle, the fuel supply corresponding to the running state of the vehicle is determined according to the determination result of whether or not to stop the fuel supply based on the allowable charging power. Therefore, the temperature of the catalyst can be adjusted appropriately until the prohibition of the stop of the fuel supply to the internal combustion engine is released based on the charge allowable power. Therefore, in this hybrid vehicle, it is possible to satisfactorily suppress the deterioration of the exhaust gas purification catalyst when the prohibition of stopping the fuel supply to the internal combustion engine is canceled based on the chargeable power and the fuel supply is stopped. Become.

  Further, the fuel increase relationship setting means is configured so that the charging allowable power is relatively large as the charging power as the acquired traveling state requires a relatively large amount of energy for deceleration of the vehicle. The fuel increase relationship may be set so that the fuel supply amount is further increased. That is, if the required driving force (braking force) at the time of deceleration request such as when the accelerator is off is supplied by regeneration with an electric motor or the like without stopping the fuel supply, the running state requires a lot of energy for vehicle deceleration. As time goes on, the regenerative power by the electric motor or the like increases, and the charge allowable power decreases as the charge power substantially within a short time. Therefore, the fuel increase relationship is such that the fuel supply amount is increased from the time when the charge allowable power is relatively large as the charge power as the driving state is a state that requires a relatively large amount of energy for deceleration of the vehicle. Is set, the temperature of the catalyst can be adjusted more appropriately before the prohibition of the stop of the fuel supply to the internal combustion engine is released based on the allowable charging power. In this case, on the contrary, the fuel increase relationship indicates that the amount of fuel supplied from the time when the allowable charging power is relatively small as the charging power, as the driving state is a state in which relatively little energy is not required for deceleration of the vehicle. Therefore, it is possible to adjust the temperature of the catalyst while setting the amount of increase in the fuel supply amount more appropriately and suppressing deterioration in fuel consumption.

  Further, in the hybrid vehicle according to the present invention, the traveling state acquisition unit may be a vehicle speed acquisition unit that detects or estimates a vehicle speed, and the fuel increase relationship setting unit determines that the detected or estimated vehicle speed is higher, The fuel increase relationship may be set so that the fuel supply amount is further increased from the time when the charge allowable power is relatively large as the charge power. In other words, the higher the vehicle speed, the more deceleration energy is required when requesting deceleration such as when the accelerator is off. Therefore, the higher the vehicle speed, the greater the amount of fuel supplied from the point when the chargeable power is relatively large as the charge power. By setting the fuel increase relationship so that the prohibition of stopping the fuel supply to the internal combustion engine is lifted based on the allowable charging power, the increase in the fuel supply amount is more appropriately set and the fuel consumption is deteriorated. It is possible to adjust the temperature of the catalyst while suppressing the above.

  In this case, the fuel supply stop determination unit may determine that the stop of the fuel supply should be prohibited when the set charge allowable power is equal to or higher than a predetermined limit value as the charge power. The relationship is that when the set charge allowable power is equal to or greater than the temporary limit value, which is larger than the limit value, as the charge power, the increase restriction is set as the first increase restriction and the set charge allowable power When the charging power becomes less than the temporary limit value, the increase restriction is set as a second increase restriction having a tendency to increase the fuel supply amount more than the first increase restriction. The relationship setting means may set the fuel increase relationship by increasing the temporary limit value as the charging power as the detected or estimated vehicle speed is higher. As a result, it is possible to easily set the fuel increase relationship in which the fuel supply amount is further increased from the time when the charge allowable power is relatively large as the charge power as the vehicle speed is higher.

  The hybrid vehicle according to the present invention may further include a catalyst temperature acquisition unit that acquires the temperature of the catalyst, and the fuel supply stop determination unit has a temperature of the acquired catalyst in a predetermined temperature range, Further, it may be determined that the stop of the fuel supply should be prohibited when the set allowable charging power is equal to or more than the limit value as the charging power.

  In the hybrid vehicle according to the present invention, the power / power input / output means is connected to the first axle, the output shaft of the internal combustion engine, and a rotatable third shaft, and any two of these three shafts. And a three-axis power input / output means for inputting / outputting power determined based on power input / output to / from the remaining shaft, and a generator capable of inputting / outputting power to / from the third shaft. .

A control method for a hybrid vehicle according to the present invention includes an internal combustion engine, a purification means including a catalyst for purifying exhaust gas discharged from the internal combustion engine, a first axle as one of the axles, and an output shaft of the internal combustion engine. And an electric power / power input / output means capable of inputting / outputting power to / from the first axle and the output shaft with input / output of electric power and power, and the first axle or an axle different from the first axle. A control method for a hybrid vehicle, comprising: an electric motor capable of inputting / outputting power to / from a second axle, and an electric power driving input / output means and an electric storage means capable of exchanging electric power between the electric motor,
(A) setting a charge allowable power set as a power allowed for charging the power storage means based on a state of the power storage means;
(B) determining whether to prohibit the stop of fuel supply to the internal combustion engine based on the set allowable charging power;
(C) setting a fuel increase relationship, which is a relationship between the allowable charging power and an increase restriction of the fuel supply amount to the internal combustion engine for adjusting the temperature of the catalyst, based on the traveling state of the hybrid vehicle; ,
(D) The internal combustion engine is operated with an increase in the fuel supply amount in accordance with an increase restriction determined from the set charge allowable power and the set fuel increase relationship according to the determination result in step (b). And controlling the internal combustion engine, the power power input / output means and the electric motor so that a required driving force required for traveling is output;
Is included.

  If the fuel increase relationship is set based on the running state of the vehicle as in this method, it corresponds to the running state of the vehicle according to the determination result of whether or not to stop the fuel supply based on the allowable charging power. It is possible to increase the fuel supply appropriately, and even if the prohibition of stopping the fuel supply to the internal combustion engine is lifted based on the chargeable power, the temperature of the catalyst can be adjusted appropriately until then. . Therefore, according to this method, it is possible to satisfactorily suppress the deterioration of the exhaust gas purifying catalyst when the prohibition of stopping the fuel supply to the internal combustion engine is canceled based on the chargeable power and the fuel supply is stopped. It becomes.

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

  FIG. 1 is a schematic configuration diagram of a hybrid vehicle according to an embodiment of the present invention. A hybrid vehicle 20 shown in FIG. 1 is connected to 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 the power distribution integration mechanism 30. The motor MG1 capable of generating electricity, the reduction gear 35 attached to the ring gear shaft 32a as a drive shaft connected to the power distribution and integration mechanism 30, the motor MG2 connected to the reduction gear 35, and the entire power output device And an electronic control unit for hybrid (hereinafter referred to as “hybrid ECU”) 70.

The engine 22 is configured as an internal combustion engine that can output power using a hydrocarbon fuel such as gasoline or light oil. As can be seen from FIG. 2, the engine 22 takes in the air cleaned by the air cleaner 122 into the intake port via the throttle valve 124 and injects gasoline from the fuel injection valve 126 to mix intake air and gasoline. The air-fuel mixture is sucked into the combustion chamber through the intake valve 128 and explosively burned by an electric spark from the spark plug 130, and the reciprocating motion of the piston 132 pushed down by the energy is converted into the rotational motion of the crankshaft 26. . Exhaust gas from the engine 22 passes through a purification device 134 having an exhaust gas purification catalyst (three-way catalyst) that purifies harmful components such as carbon monoxide (CO), hydrocarbons (HC), and nitrogen oxides (NOx). It is discharged outside. The exhaust gas purifying catalyst of the purifying device 134 may be composed of an oxidation catalyst such as platinum (Pt) or palladium (Pd), a reduction catalyst such as rhodium (Rh), and a co-catalyst such as ceria (CeO ₂ ). . In this case, CO and HC contained in the exhaust gas are purified to water (H ₂ O) and carbon dioxide (CO ₂ ) by the action of the oxidation catalyst, and NOx contained in the exhaust gas is nitrogen (N ₂ ) and is cleaned in an oxygen (O _2).

  The engine 22 configured as described above is controlled by an engine electronic control unit (hereinafter referred to as engine ECU) 24. As shown in FIG. 2, the engine ECU 24 is configured as a microprocessor centered on a CPU 24a. In addition to the CPU 24a, a ROM 24b that stores a processing program, a RAM 24c that temporarily stores data, and an input / output (not shown) And a communication port. For example, the engine ECU 24 includes a cylinder position that is a crank position from a crank position sensor 140 that detects the rotational position of the crankshaft 26, a cooling water temperature from a water temperature sensor 142 that detects a temperature of cooling water in the engine 22, and a pressure in the combustion chamber. In-cylinder pressure from a pressure sensor 143 that detects internal pressure, a cam position from a cam position sensor 144 that detects the rotational position of an intake valve 128 that performs intake and exhaust to a combustion chamber, and a camshaft that opens and closes an exhaust valve, and a throttle valve 124 The throttle position from the throttle valve position sensor 146 for detecting the position of the engine, the intake air amount GA from the air flow meter 148 provided in the intake pipe, the intake air temperature from the temperature sensor 149 provided in the intake pipe, and the purification device 134 The temperature sensor provided in Catalyst bed temperature Tcat and the like are input through the input port from the service 135. 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, and controls the operation of the engine 22 by a control signal from the hybrid electronic control unit 70, and the data regarding the operation state of the engine 22 as necessary. Output to.

  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. 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. The power distribution and integration mechanism 30 includes the motor MG1. 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.

  Both the motor MG1 and the motor MG2 are configured as well-known synchronous generator motors that can operate as a generator and operate as an electric motor, 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 bus and a negative bus shared by the inverters 41 and 42, and the power generated by any one of the motors MG 1 and MG 2 It can be consumed by a motor. Therefore, the battery 50 is charged / discharged by electric power generated from one of the 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 “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 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 ECU 70, controls the driving of the motors MG1, MG2 by a control signal from the hybrid ECU 70, and outputs data related to the operating state of the motors MG1, MG2 to the hybrid ECU 70 as necessary.

  The battery 50 is managed by a battery electronic control unit (hereinafter referred to as “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 the 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, and the battery ECU 52 communicates data regarding the state of the battery 50 as necessary. Is output to the hybrid ECU 70 and the engine ECU 24. 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 ECU 70 is configured as a microprocessor centered on the CPU 72, and includes a ROM 74 that stores a processing program, a RAM 76 that temporarily stores data, an input / output port and a communication port (not shown), in addition to the CPU 72. . The hybrid ECU 70 includes an ignition signal from the ignition switch 80, a shift position SP from the shift position sensor 82 that detects the shift position SP that is the operation position of the shift lever 81, and an accelerator pedal position sensor that detects the amount of depression of the accelerator pedal 83. The accelerator opening Acc from 84, 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 ECU 70 is connected to the engine ECU 24, the motor ECU 40, and the battery ECU 52 via the communication port, and exchanges various control signals and data with the engine ECU 24, the motor ECU 40, and the battery ECU 52.

  The hybrid vehicle 20 of the embodiment configured as described above is a request 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. Torque Tr * is calculated, and operation of engine 22, motor MG1, and motor MG2 is controlled so that power corresponding to this required torque Tr * is output to ring gear shaft 32a. As the operation control mode of the engine 22, the motor MG1, and the motor MG2, the engine 22 is operated and 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 a power distribution integration mechanism. 30, a 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 the power corresponding to the sum is output from the engine 22, and all or a part of the power output from the engine 22 with charge / discharge of the battery 50 is the power distribution integration mechanism 30 and the motor MG1. And the motor MG2 with torque conversion, the required power is ring gear A charge / discharge operation mode for driving and controlling the motor MG1 and the motor MG2 to be output to the shaft 32a, and a motor for controlling the operation so as to output the power corresponding to the required power from the motor MG2 to the ring gear shaft 32a. There are operation modes.

  Next, the operation of the hybrid vehicle 20 according to the embodiment, particularly, the operation of the hybrid vehicle 20 in the accelerator-on state accompanied by the operation of the engine 22 will be described. FIG. 3 is a flowchart showing an example of a drive control routine executed by the hybrid ECU 70 when the accelerator is on. This routine is repeatedly executed at predetermined time intervals (for example, every several milliseconds) when the accelerator operation state is in the accelerator on state.

  When the drive control routine of FIG. 3 is started, first, the CPU 72 of the hybrid ECU 70 first determines the accelerator opening Acc from the accelerator pedal position sensor 84, the vehicle speed V from the vehicle speed sensor 88, and the rotational speeds Nm1, Nm2 of the motors MG1, MG2. Then, input processing of data necessary for control such as charge / discharge required power Pb * to be charged / discharged by the battery 50 and input / output restrictions Win and Wout of the battery 50 is executed (step S100). In this case, 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 charge / discharge required power Pb * is input from the battery ECU 52 by communication. Input / output restrictions Win and Wout of the battery 50 are input from the battery ECU 52 by communication from the battery temperature Tb of the battery 50 detected by the temperature sensor 51 and the remaining capacity (SOC) of the battery 50. It was. 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 is possible to set a correction coefficient for restriction and multiply the basic value of the set input / output restrictions Win and Wout by the correction coefficient. FIG. 4 shows an example of the relationship between the battery temperature Tb and the input / output limits Win, Wout, and FIG. 5 shows an example of the relationship between the remaining capacity (SOC) of the battery 50 and the correction coefficients of the input / output limits Win, Wout.

  After the data input process in step S100, the required torque Tr * to be output to the ring gear shaft 32a as the drive shaft connected to the drive wheels 63a, 63b based on the input accelerator opening Acc and the vehicle speed V and the engine 22 are requested. The required power Pe * is set (step S110). In this embodiment, the relationship between the accelerator opening Acc and the vehicle speed V and the required torque Tr * is determined in advance and stored in the ROM 74 as a required torque setting map, and when the accelerator opening Acc and the vehicle speed V are given, the map is displayed. Therefore, the required torque Tr * corresponding to these is derived and set. FIG. 6 shows an example of the required torque setting map. Further, in the present embodiment, a value obtained by multiplying the set required torque Tr * by the rotation speed Nr (= Nm2 / Gr) of the ring gear shaft 32a and the charge / discharge required power Pb * to be charged / discharged by the battery 50 and the loss Loss The required power Pe * for the engine 22 is set as the sum. Subsequently, the target rotational speed Ne * and the target torque Te * of the engine 22 are set based on the required power Pe * for the engine 22 set in step S110 (step S120). In the embodiment, the target rotational speed Ne * and the target torque Te * as the target operating point of the engine 22 are set based on the operation line for efficiently operating the engine 22 and the required power Pe *. FIG. 7 illustrates an example of an operation line of the engine 22 and a correlation curve between the target rotational speed Ne * and the target torque Te *. As shown in the figure, the target rotational speed Ne * and the target torque Te * can be obtained from the intersection of the operation line and the correlation curve indicating that the required power Pe * (Ne * × Te *) is constant.

  Further, based on the target rotational speed Ne * set in step S120, 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 calculation using the following equation (1) is performed. The target rotational speed Nm1 * of the motor MG1 is obtained, and the torque command Tm1 * of the motor MG1 is set by calculation using the following equation (2) based on the obtained target rotational speed Nm1 * and the current rotational speed Nm1 ( Step S130). Expression (1) is a dynamic relational expression related to the rotating element of the power distribution and integration mechanism 30. FIG. 8 is a collinear diagram showing a dynamic relationship between the rotational speed and torque of each rotary element in the power distribution and integration mechanism 30. In the figure, the left S-axis indicates the rotational speed of the sun gear 31 that matches the rotational speed Nm1 of the motor MG1, the C-axis indicates the rotational speed of the carrier 34 that matches the rotational speed Ne of the engine 22, and the R-axis indicates the motor MG2. The rotational speed Nr of the ring gear 32 obtained by dividing the rotational speed Nm2 by the gear ratio Gr of the reduction gear 35 is shown. Further, two thick arrows on the R axis indicate that the torque acting on the ring gear shaft 32a by this torque output when the torque Tm1 is output from the motor MG1 and the torque Tm2 output from the motor MG2 via the reduction gear 35. The torque acting on the ring gear shaft 32a is shown. Equation (1) for obtaining the target rotational speed Nm1 * of the motor MG1 can be easily derived by using the rotational speed relationship in this alignment chart. In the equation (1), ρ is the gear ratio of the power distribution and integration mechanism 30 (the number of teeth of the sun gear 31 / the number of teeth of the ring gear 32). In the equation (2), “k1” in the second term on the right side is The gain of the proportional term, and “k2” in the third term on the right side is the gain of the integral term.

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

  When the torque command Tm1 * is set, the current motor MG1 is added to the output limit Wout or the input limit Win of the battery 50 input in step S100 according to the following equations (3) and (4), and the set torque command Tm1 * of the motor MG1. The torque limits Tmax and Tmin as upper and lower limits of the torque that may be output from the motor MG2 are calculated by dividing the deviation from the power consumption of the motor MG1 obtained by multiplying the rotation speed Nm1 by the rotation speed Nm2 of the motor MG2. (Step S140). Further, a temporary motor as a torque to be output from the motor MG2 according to the following equation (5) using the required torque Tr *, the torque command Tm1 *, the gear ratio ρ of the power distribution and integration mechanism 30 and the gear ratio Gr of the reduction gear 35. Torque Tm2tmp is calculated (step S150), and torque command Tm2 * of motor MG2 is set by limiting calculated temporary motor torque Tm2tmp with torque limits Tmax and Tmin (step S160). By setting the torque command Tm2 * of the motor MG2 in this way, the required torque Tr * output to the ring gear shaft 32a is basically set as a torque that is limited within the range of the input / output limits Win and Wout of the battery 50. be able to. Equation (5) can be easily derived from the alignment chart of FIG. When the target rotational speed Ne * and target torque Te * of the engine 22 and the torque commands Tm1 * and Tm2 * of the motors MG1 and MG2 are thus set, the target rotational speed Ne * and the target torque Te * of the engine 22 are transferred to the engine ECU 24 and the motor. Torque commands Tm1 * and Tm2 * of MG1 and MG2 are transmitted to motor ECU 40, respectively (step S170). The engine ECU 24 having received the target rotational speed Ne * and the target torque Te *, based on the received target rotational speed Ne * and the target torque Te *, stores a fuel injection amount setting map (not shown) and a throttle stored in the ROM 24b. A fuel injection amount for the engine 22, a position of the throttle valve 124 (throttle opening), and the like are determined using an opening setting map and the like, and control for obtaining the target rotational speed Ne * and the target torque Te * is executed. . The motor ECU 40 that has received the torque commands Tm1 * and Tm2 * switches the switching elements of the inverters 41 and 42 so that the motor MG1 is driven according to the torque command Tm1 * and the motor MG2 is driven according to the torque command Tm2 *. Take control.

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

  Here, when the vehicle speed V is higher than the relatively high predetermined vehicle speed through the accelerator-on state accompanied by the operation of the engine 22 as described above, the depression of the accelerator pedal 83 is released by the driver and a deceleration request is made. In this case, the fuel injection to the engine 22 is basically stopped, and the required torque when the accelerator opening degree determined from the required torque setting map of FIG. 6 is 0% (accelerator off) while mainly using the engine brake ( The engine 22 and the motors MG1 and MG2 are controlled so that (braking torque) Tr * is obtained. However, if fuel injection to the engine 22 is stopped when the exhaust gas purification catalyst of the purification device 134 is in a high temperature state, only the air that has passed through the combustion chamber is supplied to the purification device 134, and the exhaust gas purification catalyst is in a lean atmosphere. When exposed to the catalyst, the oxidation catalyst or the reduction catalyst grows and the surface area decreases, which may cause deterioration of the exhaust gas purification catalyst (decrease in purification function). For this reason, depending on the temperature of the exhaust gas purifying catalyst (catalyst bed temperature Tcat), stop of fuel injection to the engine 22 (hereinafter referred to as “fuel cut”) is prohibited, and the fuel injection amount to the engine 22 is appropriately increased and corrected. It is preferable to adjust the catalyst bed temperature Tcat of the exhaust gas purification catalyst. On the other hand, when a deceleration request based on accelerator-off is made in a state where fuel cut is prohibited, the hybrid vehicle 20 controls the engine 22 and the motors MG1 and MG2 to perform fuel injection to the engine 22 according to predetermined conditions. While continuing ignition (firing) and adjusting the opening of the throttle valve 124, the engine 22 is output from the engine 22 to the motor MG2 while gradually reducing the engine 22 to a predetermined engine speed (for example, engine speed during idling). The required torque (braking torque) Tr * when the accelerator opening determined from the required torque setting map of FIG. In this case, the motor MG2 generates electric power as the braking force is generated, and the regenerative electric power is stored in the battery 50. However, the input limit as charging allowable electric power that is allowable electric power for charging the battery 50 is used. Depending on the value of Win, such regeneration by the motor MG2 may be limited. For this reason, in the hybrid vehicle 20 of the present embodiment, the fuel injection amount for the engine 22 is increased and corrected while considering both the catalyst bed temperature Tcat of the exhaust gas purification catalyst of the purification device 134 and the input limit Win of the battery 50. A catalyst deterioration suppression determination routine described below is executed so that deterioration of the exhaust gas purification catalyst can be suppressed.

  FIG. 9 is a flowchart showing an example of a catalyst deterioration suppression determination routine. This routine is repeatedly executed by the engine ECU 24 every predetermined time. When the catalyst deterioration suppression determination routine of FIG. 9 is started, the CPU 24a of the engine ECU 24 first determines the catalyst bed temperature Tcat from the temperature sensor 135 provided in the purification device 134, the input limit Win of the battery 50, and the vehicle speed V. The data input process necessary for the process is executed (step S200). In this case, the input limit Win of the battery 50 is input from the battery ECU 52 by communication. Further, when the temperature sensor 135 of the purification device 134 is omitted, the catalyst bed temperature Tcat is estimated from the rotational speed Ne of the engine 22, the intake air amount, an increase in the fuel injection amount described later, and the like. May be entered. Further, the vehicle speed V may be input by communication from the hybrid ECU 70 or may be directly input from the vehicle speed sensor 88. Then, after the data input process of step S200, it is determined whether or not the input catalyst bed temperature Tcat is equal to or higher than a predetermined first threshold value Tref1 (step S210). The first threshold value Tref1 used here is determined based on a first target bed temperature T1 (for example, 920 ° C.) when the increase in the catalyst bed temperature Tcat is suppressed to the extent that deterioration of the exhaust gas purification catalyst is suppressed. Is.

  If it is determined in step S210 that the catalyst bed temperature Tcat is equal to or higher than the first threshold Tref1 and the exhaust gas purification catalyst is in a high temperature state, the input limit Win of the battery 50 is determined based on the vehicle speed V input in step S200. A temporary limit value Win0 is set as a threshold value related to (step S220). The temporary limit value Win0 is the limit value of the input limit value Win of the battery 50 when the torque (braking torque) required when the accelerator is off is supplied by the regenerative braking force by the motor MG2 without cutting the fuel (minimum charging power) Value) A value that is smaller than Win1, that is, a value that is large (with a margin) as charging power. In the embodiment, the relationship between the vehicle speed V and the temporary limit value Win0 is determined in advance and stored in the ROM 74 as a temporary limit value setting map as illustrated in FIG. 10, and when the vehicle speed V is given, the map corresponds to that. The provisional limit value Win is derived and set. Since the input limit Win is originally a negative value, the input limit Win is equal to or less than the temporary limit value Win0, that is, the input limit Win is equal to or higher than the temporary limit value Win0 as the charging power. This means that a relatively large value (a value with a large absolute value) can be set as the power.

  Subsequently, it is determined whether or not the input limit Win input in step S200 is equal to or less than the temporary limit value Win0 (step S230). If the input limit Win is less than or equal to the temporary limit value Win0, the temporary prohibition flag Ft is set to 0 (step S240), and the fuel for the engine 22 set using the fuel injection amount setting map described above is set. As a map for setting an increase coefficient for increasing the injection amount, a first OT increase coefficient setting map illustrated in FIG. 11A is read from the ROM 24b and set, and the above-described throttle opening setting map is used. When a first TA correction map (not shown) for correcting the set opening degree of the throttle valve 124 is read from the ROM 24b and set (step S250), and further, fuel cut is permitted to prohibit the fuel cut. The fuel cut prohibition flag Fc that is set to 0 is set to 1 (step S260), and this routine is terminated once.

  Thus, when the first OT increase coefficient setting map or the first TA correction map is set as a map for setting the increase coefficient in step S250, the fuel cut is prohibited in step S260, and the engine ECU 24 is controlled by the hybrid ECU 70. When setting the fuel injection amount for the engine 22 and the opening degree of the throttle valve 124 based on the target rotational speed Ne * and the target torque Te *, which are the command values of the engine, and the predetermined restrictions when the fuel cut is prohibited, from these maps A fuel injection amount increase or a throttle opening correction is executed in accordance with the derived fuel injection amount increase coefficient or the throttle opening correction coefficient. As illustrated in FIG. 11A, the first OT increase coefficient setting map defines an increase coefficient in accordance with the target rotational speed Ne * of the engine 22 and the volumetric efficiency KL related to the intake air amount. Basically, it is created so as to take a larger value as the increase coefficient as the target rotational speed Ne * and the volumetric efficiency KL increase. In this embodiment, the first OT increase coefficient setting map maintains the catalyst bed temperature Tcat substantially at the above-mentioned first target bed temperature T1 according to the target rotational speed Ne * of the engine 22 and the volumetric efficiency KL, and increases it. It is created so as to define an increase coefficient of the fuel injection amount for suppressing the fuel injection. As a result, when the first OT increase coefficient setting map is set, the amount of increase in the fuel injection amount is relatively small, so that the fuel consumption required for temperature adjustment to suppress the deterioration of the exhaust gas purification catalyst is reduced. Can do. The first TA correction map (not shown) cancels the deviation between the target torque Te * resulting from increasing the fuel injection amount based on the first OT increase coefficient setting map and the torque actually output from the engine 22. As described above, the throttle opening correction coefficient is created in advance in accordance with the target rotational speed Ne * and the target torque Te *. That is, the correction coefficient for the throttle opening in the first TA correction map is set, for example, so as to make the throttle opening smaller than normal in an operating region where the torque increases when the fuel injection amount is increased. The operating range in which the torque sometimes decreases is determined to make the throttle opening smaller than usual. Thereby, when the fuel injection amount increase correction is executed using the first OT increase coefficient setting map, the shock due to the deviation between the target torque Te * and the torque actually output from the engine 22 is reduced. be able to.

  On the other hand, if it is determined in step S230 that the input limit Win exceeds the temporary limit value Win0, the temporary prohibition flag that is set to 0 when the input limit Win is equal to or less than the temporary limit value Win0. After setting Ft to the value 1 (step S270), it is determined whether or not the input limit Win input in step S200 is equal to or less than the limit value Win1 (step S280). When the input limit Win is equal to or less than the limit value Win1, that is, when the charging power is equal to or greater than the limit value Win1, the increase for correcting the increase in the fuel injection amount for the engine 22 set using the fuel injection amount setting map described above. As a map for setting a coefficient, a second OT increase coefficient setting map illustrated in FIG. 11B having a tendency to increase the fuel injection amount as compared with the first OT increase coefficient setting map is read from the ROM 24b and set. At the same time, a second TA correction map (not shown) for correcting the opening of the throttle valve 124 set using the throttle opening setting map is read from the ROM 24b and set (step S290). The fuel cut prohibition flag Fc is set to a value 1 (step S260), and this routine is temporarily terminated. If it is determined in step S280 that the input limit Win exceeds the limit value Win1, the temporary prohibition flag Ft is set to 0 (step S320), and the fuel is set according to the state of the battery 50. A fuel cut prohibition flag Fc is set to 0 to cancel the prohibition of cut (step S330).

  Thus, even when the second OT increase coefficient setting map or the second TA correction map is set as the map for setting the increase coefficient in step S290, the fuel cut is prohibited in step S270, and the engine ECU 24 is controlled by the hybrid ECU 70. When the fuel injection amount for the engine 22 and the opening degree of the throttle valve 124 are set based on the target rotational speed Ne *, the target torque Te *, etc., the fuel injection amount increase coefficient derived from these maps and the throttle The fuel injection amount is increased or the throttle opening is corrected according to the opening correction coefficient. The second OT increase coefficient setting map also defines an increase coefficient according to the target rotational speed Ne * of the engine 22 and the volumetric efficiency KL related to the intake air amount, as illustrated in FIG. 11B. Basically, it is created so as to take a larger value as the increase coefficient as the target rotational speed Ne * and the volumetric efficiency KL increase. In the present embodiment, the second OT increase coefficient setting map may deteriorate the catalyst bed temperature Tcat according to the target rotational speed Ne * of the engine 22 and the volumetric efficiency KL even if the exhaust gas purification catalyst is exposed to a lean atmosphere. It is created so as to define an increase coefficient of the fuel injection amount for lowering to a small second target bed temperature T2 (for example, 850 ° C.). That is, the second OT increase coefficient setting map is created so as to take a larger increase coefficient while the target rotational speed Ne * and the volumetric efficiency KL are relatively lower than the first OT increase coefficient setting map. When the 2OT increase coefficient setting map is set, the fuel injection amount increases basically as the vehicle speed V is higher than when the first OT increase coefficient setting map is set. Further, the second TA correction map (not shown) cancels the deviation between the target torque Te * resulting from the increase in the fuel injection amount based on the second OT increase coefficient setting map and the torque actually output from the engine 22. As described above, the throttle opening correction coefficient is created in advance in accordance with the target rotational speed Ne * and the target torque Te *. As a result, even when the fuel injection amount increase correction is executed using the second OT increase coefficient setting map, the shock caused by the deviation between the target torque Te * and the torque actually output from the engine 22 is reduced. can do.

  Thus, in the hybrid vehicle 20 of the embodiment, the first OT increase coefficient setting map for determining the increase amount of the fuel injection amount according to the comparison result between the input limit Win of the battery 50 and the temporary limit value Win0, One of the second OT increase coefficient setting maps is selected, but the temporary limit value Win0 as a threshold is set as follows on the assumption that the fuel injection amount is increased using the second OT increase coefficient setting map. Determined. In other words, the temporary limit value Win0 is basically in accordance with the following equation (6), approximately equal to the first target bed temperature T1 when the catalyst bed temperature Tcat suppresses the temperature rise to the extent that deterioration of the exhaust gas purification catalyst is suppressed. The second target bed temperature is less likely to deteriorate even if the exhaust gas purification catalyst is exposed to a lean atmosphere by increasing the fuel injection amount using the second OT increase coefficient setting map when the two coincide with each other. Determined by obtaining the minimum time T required to decrease to T2 by experiment and analysis, and adding the value obtained by multiplying the obtained minimum time T by the maximum change amount ΔWin per unit time of the input limit Win and the limit value Win1. It is done. Here, the maximum change amount ΔWin in the equation (6) substantially changes according to the traveling state of the hybrid vehicle 20. That is, as the vehicle speed V is higher, the energy held by the hybrid vehicle 20 is larger. As can be seen from FIG. 6, the required torque Tr * set when the accelerator is off increases as the braking torque as the vehicle speed V increases. Therefore, if the braking torque required when the accelerator is off is supplied by the regenerative braking force by the motor MG2 without cutting the fuel, the higher the vehicle speed V, the greater the regenerative energy by the motor MG2, and the motor corresponding to the maximum change amount ΔWin. The power per unit time input from MG2 to battery 50 increases. That is, as the vehicle speed V is higher, the input limit Win as the charge allowable power is apparently reduced as the charge power in a short time. In consideration of such points, in the embodiment, the braking torque required when the accelerator is off is supplied by the regenerative braking force by the motor MG2 without cutting the fuel, and is input from the motor MG2 to the battery 50 for each vehicle speed V. A temporary limit value setting map for prescribing the relationship between the vehicle speed V and the temporary limit value Win0 is created in advance based on the equation (6) after obtaining the power per unit time as the maximum change amount ΔWin by analysis or the like. ing. As shown in FIG. 10, the temporary limit value setting map is basically created so that the higher the vehicle speed V, the smaller the value of the temporary limit value Win0 (the absolute value is larger).

  Win0 = Win1 + ΔWin · T (6)

  As described above, when the temporary prohibition flag Ft is set to the value 1 in step S270 and the second OT increase coefficient setting map is set in step S290, the catalyst bed temperature Tcat basically decreases. When the catalyst deterioration suppression determination routine is executed again, it may be determined that the catalyst bed temperature Tcat input in step S200 is less than the first threshold value Tref1, and the catalyst bed temperature Tcat is less than the first threshold value Tref1. When it is, it is determined whether or not the temporary prohibition flag Ft is a value 1 (step S300). If the temporary prohibition flag Ft is a value 1, the input catalyst bed temperature Tcat is the above-mentioned second target bed temperature. It is determined whether or not it is less than a second threshold Tref2 determined based on T2 (step S310). When the catalyst bed temperature Tcat is equal to or higher than the second threshold value Tref2, it is determined whether or not the input input limit Win is equal to or lower than the limit value Win1 (step S280), and if the input limit Win is equal to or lower than the limit value Win1. For example, the second OT increase coefficient setting map and the second TA correction map are read from the ROM 24b and set (step S290), and the fuel cut prohibition flag Fc is set to a value 1 to prohibit fuel cut (step S260). ), This routine is temporarily terminated. If the input limit Win exceeds the limit value Win1, the temporary prohibition flag Ft is set to a value 0 (step S320), and the fuel cut is prohibited in order to cancel the fuel cut prohibition according to the state of the battery 50. The flag Fc is set to 0 (step S330). On the other hand, when the catalyst bed temperature Tcat is lower than the second threshold value Tref2, the catalyst bed temperature Tcat is reduced to the second target bed temperature T2, which is less likely to deteriorate even when the exhaust gas purification catalyst is exposed to a lean atmosphere. Therefore, the temporary prohibition flag Ft is set to 0 (step S320), and then the fuel cut prohibition flag Fc is set to 0 to cancel the fuel cut prohibition (step S330). Further, when it is determined in step S300 that the temporary prohibition flag Ft is 0, the catalyst bed temperature Tcat is kept at a relatively low temperature without increasing the fuel injection amount according to the second OT increase coefficient setting map. Therefore, in this case, it is considered that there is little possibility that the exhaust gas purification catalyst will deteriorate even if the fuel cut is allowed, and the fuel cut prohibition flag Fc is set to 0 (step S330).

  The time chart of FIG. 12 illustrates the transition of the input limit Win, the temporal transition of the catalyst bed temperature Tcat, the setting condition of the increase coefficient, the fuel cut prohibition flag Fc, and the temporary prohibition flag Ft when the above-described series of processing is executed. To do. Note that the input limit Win does not necessarily depend on a change with time, but in FIG. 12, it is shown as a change with time in order to make the description easy to understand. As can be seen from FIG. 12, when the first OT increase coefficient setting map is set according to the state of the battery 50 when the exhaust gas purification catalyst is in a high temperature state (Tcat ≧ Tref1), fuel injection to the engine 22 is performed according to the map. The amount is corrected to increase, and the catalyst bed temperature Tcat is basically maintained at the first target bed temperature T1. Further, when the gas purification catalyst is in a predetermined temperature range (for example, a region exceeding 850 ° C.) and the input limit Win of the battery 50 is within the range of the temporary limit value Win0 to the limit value Win1, the temporary prohibition flag Ft is set. The second OT increase coefficient setting map is set to the value 1, and the fuel injection amount for the engine 22 is corrected to be increased so that the catalyst bed temperature Tcat basically decreases to the second target bed temperature T2. become. In the hybrid vehicle 20 of the embodiment, the temporary limit value Win0 is set larger as the charging power as the vehicle speed V is higher as described above (see Win0 ′ in FIG. 12). As indicated by the chain line, the catalyst bed temperature Tcat may be deteriorated even if the exhaust gas purification catalyst is exposed to a lean atmosphere from the stage where the input limit Win of the battery 50 has a margin as compared with the low vehicle speed indicated by the solid line in FIG. The increase in the fuel injection amount using the second OT increase coefficient setting map is started so as to decrease to the small second target bed temperature T2.

  As described above, in the hybrid vehicle 20 of the present embodiment, the amount of fuel injection to the engine 22 for adjusting the input limit Win of the battery 50 and the temperature of the exhaust gas purification catalyst based on the vehicle speed V indicating the traveling state is increased. A temporary limit value Win0 that defines the relationship with the first and second OT increase coefficient setting maps as a constraint is set. When the fuel cut is prohibited (including when the accelerator is on and when fuel injection is continued) according to the determination result of whether or not the fuel cut performed based on the input limit Win is prohibited, The engine 22 is operated with the increase in the fuel injection amount according to the first or second OT increase coefficient setting map set based on the limit value Win0, and the driving force based on the set required torque Tr * Engine 22 and motors MG1 and MG2 are controlled so that (braking force) is output. Thus, if the temporary limit value Win0 is set based on the vehicle speed V indicating the traveling state of the hybrid vehicle 20, the traveling is performed according to the determination result of whether or not the fuel cut based on the input limit Win of the battery 50 is prohibited. The fuel injection amount corresponding to the state can be increased appropriately, and the temperature of the exhaust gas purification catalyst must be adjusted appropriately by that time even if the fuel cut prohibition is canceled based on the input restriction Win Can do. Therefore, in the hybrid vehicle 20, it is possible to satisfactorily suppress the deterioration of the exhaust gas purification catalyst when the prohibition of fuel cut is canceled based on the input limit Win of the battery 50 and the fuel cut is actually executed.

  That is, in the hybrid vehicle 20 of the embodiment, if the required torque (braking torque) Tr * when the accelerator is off is supplied by regeneration by the motor MG2 without cutting the fuel, the running state requires a lot of energy for deceleration. The higher the vehicle speed state, the larger the regenerative power by the motor MG2, and the input restriction Win becomes smaller as charging power in an apparently short time. Therefore, the higher the vehicle speed V that requires a relatively large amount of energy for deceleration, the more the fuel injection amount is increased according to the second OT increase coefficient setting map from the time when the input restriction Win is relatively large as the charging power. If the temporary limit value Win0 is set, the temperature of the exhaust gas purification catalyst can be adjusted more appropriately before the prohibition of fuel cut is canceled based on the input limit Win. On the contrary, the temporary limit value Win0 becomes the second OT increase coefficient from the time when the charge allowable power Win is relatively small as the charge power, when the traveling state is a low vehicle speed state that does not require relatively much energy for deceleration. Since the fuel injection amount is set to be further increased according to the setting map, the increase amount of the fuel injection amount is more appropriately set before the prohibition of fuel cut is canceled based on the input limit Win. Thus, it is possible to adjust the temperature of the exhaust gas purification catalyst while suppressing deterioration of fuel consumption. As described above, when the input limit Win of the battery 50 is equal to or higher than the temporary limit value Win0 as the charging power, the first OT increase coefficient setting map is used and the input limit Win of the battery 50 is the temporary limit value Win0 as the charging power. When the second OT increase coefficient map has a tendency to increase the fuel injection amount more than the first OT increase coefficient setting map, the temporary limit value Win0 becomes larger as the charging power as the vehicle speed V increases. In this case, as the vehicle speed V increases, it is possible to easily increase the fuel injection amount from the time when the input limit Win of the battery 50 has a margin.

  In the hybrid vehicle 20, as the intake air amount GA of the engine 22 increases, the amount of exhaust gas sent to the purification device 134 increases, and the heat energy taken away from the exhaust gas purification catalyst by the exhaust gas increases. It becomes easy to lower the temperature. That is, the minimum time T in the above equation (6) becomes shorter as the operating state of the engine 22 is in a state where more air is inhaled and more air is fed into the purifier 134. For this reason, when the temporary limit value Win0 is determined with the minimum time T constant, the input limit Win of the battery 50 is relatively small even though the minimum time T is relatively short in relation to the intake air amount GA. The second OT increase coefficient setting map is set from a stage where there is a margin, and there is a possibility that a wasteful increase in the fuel injection amount may be performed. In consideration of such points, as a temporary limit value setting map, the relationship between the vehicle speed V indicating the running state of the hybrid vehicle 20, the intake air amount GA indicating the operating state of the engine 22, and the temporary limit value Win0 is shown. Prepare the ones to be defined in advance, and set the temporary limit value Win0 as the charging power to a smaller value as the intake air amount GA of the engine 22 increases under the relationship between the vehicle speed V and the temporary limit value Win0. May be. As a result, it is possible to adjust the temperature of the exhaust gas purification catalyst while setting the increased amount of the fuel injection amount more appropriately and suppressing the deterioration of fuel consumption.

  The embodiments of the present invention have been described above using the embodiments. However, the present invention is not limited to the above embodiments, and various modifications can be made without departing from the scope of the present invention. Needless to say.

  That is, in the hybrid vehicle 20 of the above embodiment, the ring gear shaft 32a as the drive shaft and the motor MG2 are connected via the reduction gear 35 that reduces the rotational speed of the motor MG2 and transmits it to the ring gear shaft 32a. Instead of the reduction gear 35, for example, a transmission that has two or three shift stages of Hi and Lo and shifts the rotation speed of the motor MG2 and transmits it to the ring gear shaft 32a may be adopted. Good.

  Further, in the hybrid vehicle 20 of the above embodiment, the power of the motor MG2 is decelerated by the reduction gear 35 and output to the ring gear shaft 32a. However, like the hybrid vehicle 120 as a modified example shown in FIG. 13, the motor MG2 The transmission power is shifted by the transmission 65 and the axle (the axle connected to the wheels 63c and 63d in FIG. 13) is different from the axle to which the ring gear shaft 32a is connected (the axle to which the drive wheels 63a and 63b are connected). You may make it transmit.

  Further, the hybrid vehicle 20 of each of the above embodiments outputs the power of the engine 22 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. 14 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. Then, a counter-rotor motor 230 that transmits a part of the power of the engine 22 to the drive shaft and converts the remaining power into electric power may be provided.

1 is a schematic configuration diagram of a hybrid vehicle 20 according to an embodiment of the present invention. 2 is a schematic configuration diagram of an engine 22. FIG. It is a flowchart which shows an example of the drive control routine performed by the hybrid ECU70 of an Example at the time of accelerator ON. It is explanatory drawing which shows an example of the relationship between the battery temperature Tb in the battery 50, and the input / output restrictions Win and Wout. It is explanatory drawing which shows an example of the relationship between the remaining capacity (SOC) of the battery 50, and the correction coefficient of input / output restrictions Win and Wout. It is explanatory drawing which shows an example of the map for request | requirement torque setting. It is explanatory drawing which illustrates the operation line of the engine 22, the correlation curve of target rotational speed Ne *, and target torque Te *. 3 is a collinear diagram illustrating a dynamic relationship between the rotational speed and torque of each rotary element in the power distribution and integration mechanism 30. FIG. It is a flowchart which shows an example of the catalyst deterioration suppression determination routine performed by engine ECU24 of a 1st Example. It is explanatory drawing which shows an example of the map for temporary limit value setting. (A) is explanatory drawing which illustrates the 1st OT increase coefficient setting map, (b) is explanatory drawing which illustrates the 2nd OT increase coefficient setting map. The time illustrating the transition of the input limit Win, the temporal transition of the catalyst bed temperature Tcat, the increase coefficient, the fuel cut prohibition flag Fc, and the setting state of the temporary prohibition flag Ft when the catalyst deterioration suppression determination routine of FIG. 9 is executed. It is a chart. It is a schematic block diagram of the hybrid vehicle 120 of the modification. It is a schematic block diagram of the hybrid vehicle 220 of a modification.

Explanation of symbols

  20, 120, 220 Hybrid vehicle, 22 engine, 24 engine electronic control unit (engine ECU), 24a, 72 CPU, 24b, 74 ROM, 24c, 76 RAM, 26 crankshaft, 28 damper, 30 power distribution integration mechanism, 31 sun gear, 32 ring gear, 32a ring gear shaft, 33 pinion gear, 34 carrier, 35 reduction gear, 40 electronic control unit for motor (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, 65 transmission, 70 hybrid electronic control unit (hybrid) ECU), 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, 135 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 valve Position sensor, 148 Air flow meter, 149 Temperature sensor, 150 Variable valve timing mechanism, 230 Rotor motor, 232 an inner rotor, 234 outer rotor, MG1, MG2 motor.

Claims (7)

An internal combustion engine;
Purification means including a catalyst for purifying exhaust gas discharged from the internal combustion engine;
Power power input / output means connected to the first axle as one of the axles and the output shaft of the internal combustion engine and capable of inputting / outputting power to / from the first axle and the output shaft with input / output of power and power When,
An electric motor capable of inputting / outputting power to / from a second axle that is either the first axle or an axle different from the first axle;
Power storage means capable of exchanging power between the power drive input / output means and the electric motor;
Charge allowable power setting means for setting charge allowable power that is power allowed for charging of the power storage means based on the state of the power storage means;
Fuel supply stop determination means for determining whether or not to stop the fuel supply to the internal combustion engine based on the set allowable charge power;
Traveling state acquisition means for acquiring the traveling state of the vehicle;
Required driving force setting means for setting required driving force required for traveling;
Fuel increase relationship setting means for setting a fuel increase relationship that is a relationship between the allowable charging power and the increase restriction of the fuel supply amount to the internal combustion engine for adjusting the temperature of the catalyst based on the acquired traveling state. When,
The internal combustion engine is operated with an increase in the fuel supply amount in accordance with an increase restriction determined from the set charge allowable power and the set fuel increase relationship according to the determination result by the fuel supply stop determination means. And a control means for controlling the internal combustion engine, the power power input / output means and the electric motor so that a driving force based on the set required driving force is output.
A hybrid vehicle comprising:   The fuel increase relationship setting means determines that the fuel increasing power from the point of time when the chargeable power is relatively large as the charge power, when the acquired traveling state requires a relatively large amount of energy for vehicle deceleration. The hybrid vehicle according to claim 1, wherein the fuel increase relationship is set so that the supply amount is further increased. In the hybrid vehicle according to claim 1 or 2,
The traveling state acquisition means is vehicle speed acquisition means for detecting or estimating a vehicle speed,
The fuel increase relationship setting means sets the fuel increase relationship such that the higher the detected or estimated vehicle speed is, the more the fuel supply amount is increased from the time when the charge allowable power is relatively large as the charge power. Hybrid vehicle. In the hybrid vehicle according to claim 3,
The fuel supply stop determination means determines that the fuel supply stop should be prohibited when the set charge allowable power is a predetermined limit value or more as charge power,
The fuel increase relationship is set while the increase restriction is set as a first increase restriction when the set charge allowable power is equal to or greater than a temporary limit value that is a value larger than the limit value as the charge power. When charging allowable power is less than the temporary limit value as charging power, the increase restriction is a second increase restriction having a tendency to increase the fuel supply amount more than the first increase restriction,
The fuel increase relationship setting means is a hybrid vehicle that sets the fuel increase relationship by increasing the temporary limit value as charging power as the detected or estimated vehicle speed is higher. The hybrid vehicle according to claim 4,
A catalyst temperature acquisition means for acquiring the temperature of the catalyst;
The fuel supply stop determination means prohibits the fuel supply stop when the acquired catalyst temperature is in a predetermined temperature range and the set charge allowable power is equal to or higher than the limit value as charge power. A hybrid vehicle that should be judged.   The power power input / output means is connected to the first axle, the output shaft of the internal combustion engine, and a rotatable third shaft, and based on power input / output to any two of these three shafts. 6. The hybrid vehicle according to claim 1, further comprising: a three-axis power input / output unit that inputs / outputs fixed power to / from a remaining shaft; and a generator that can input / output power to / from the third shaft. An internal combustion engine, purification means including a catalyst for purifying exhaust gas discharged from the internal combustion engine, a first axle as one of the axles, and an output shaft of the internal combustion engine are connected to input power and power. Power is input / output means capable of inputting / outputting power to / from the first axle and the output shaft with output, and power is applied to the second axle, which is either the first axle or an axle different from the first axle. A control method for a hybrid vehicle, comprising: an electric motor capable of input / output; and a power storage means capable of exchanging electric power between the electric power drive input / output means and the electric motor,
(A) setting a charge allowable power set as a power allowed for charging the power storage means based on a state of the power storage means;
(B) determining whether to prohibit the stop of fuel supply to the internal combustion engine based on the set allowable charging power;
(C) setting a fuel increase relationship, which is a relationship between the allowable charging power and an increase restriction of the fuel supply amount to the internal combustion engine for adjusting the temperature of the catalyst, based on the traveling state of the hybrid vehicle; ,
(D) The internal combustion engine is operated with an increase in the fuel supply amount in accordance with an increase restriction determined from the set charge allowable power and the set fuel increase relationship according to the determination result in step (b). And controlling the internal combustion engine, the power power input / output means, and the electric motor so that a driving force required for traveling is output;
A control method for a hybrid vehicle including:

Images