JP2012153167A - Hybrid vehicle and control method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To more improve fuel consumption of an internal combustion engine that has an exhaust gas recirculation device, and consequently improve more the efficiency of energy in a hybrid vehicle that includes this internal combustion engine.SOLUTION: The request power to the engine that has an EGR device installed in the hybrid vehicle is set based on requested traveling power requested for travel and electrical charge and discharge request power Pb* of the battery. When the charge for the battery is requested and the exhaust gas recirculation is executed by the EGR device, the electrical charge and discharge request power Pb* is increased by the charge side so that the request power may increase compared with time when the charge for the battery is requested and the exhaust gas recirculation is not executed.

Description

  The present invention relates to a hybrid vehicle including an internal combustion engine having an exhaust gas recirculation device, an electric motor capable of generating electric power using at least a part of power from the internal combustion engine, and a power storage device capable of exchanging electric power with the electric motor. It relates to the control method.

  Conventionally, as a hybrid vehicle of this type, a predetermined power that is required for an internal combustion engine when exhaust gas recirculation (EGR) is not executed and an internal combustion engine that is efficiently operated without exhaust gas recirculation is predetermined. The operation point (target rotational speed and target torque) of the internal combustion engine is set using the operation line, and the internal combustion engine is operated efficiently with the required power and exhaust gas recirculation when exhaust gas recirculation is executed. Is known in which an operation point of the internal combustion engine is set using a predetermined second operation line (see, for example, Patent Document 1). In this hybrid vehicle, the operating point of the internal combustion engine at the time of exhaust gas recirculation is moved to the higher rotation side and the lower torque side than the operating point at the time of non-execution of exhaust gas recirculation corresponding to the same required power. First and second operation lines are defined.

JP 2010-077655

  The exhaust gas recirculation described above is employed to reduce NOx and improve the fuel efficiency of the internal combustion engine. However, the operation points of the internal combustion engine for the same required power are set to the same required power when the exhaust gas recirculation is not executed and when the exhaust gas recirculation is not executed using the different operation lines when the exhaust gas recirculation is not executed and when the exhaust gas recirculation is executed. However, the fuel efficiency during exhaust gas recirculation may not be improved significantly.

  SUMMARY OF THE INVENTION Accordingly, the main object of the present invention is to further improve the fuel efficiency of the internal combustion engine in the hybrid vehicle including the internal combustion engine having the exhaust gas recirculation device, and further improve the energy efficiency of the hybrid vehicle.

  The hybrid vehicle and the control method thereof according to the present invention employ the following means in order to achieve the main object.

The hybrid vehicle according to the present invention
A driving force required amount by a driver comprising an internal combustion engine having an exhaust gas recirculation device, an electric motor capable of generating electric power using at least a part of power from the internal combustion engine, and a power storage device capable of exchanging electric power with the electric motor. In a hybrid vehicle that controls the internal combustion engine and the electric motor according to
When exhaust gas recirculation is executed by the exhaust gas recirculation device, the output power of the internal combustion engine for the same required driving force is increased as compared to when the exhaust gas recirculation is not executed.

  As a result of intensive studies on the internal combustion engine having the exhaust gas recirculation device by the present inventors, the power output from the internal combustion engine when the efficiency (fuel consumption rate) of the internal combustion engine becomes the best is the exhaust gas recirculation power. It was found that the exhaust gas recirculation becomes higher than the non-execution when the exhaust gas is recirculated, and this tendency becomes stronger as the exhaust gas recirculation amount increases. Based on such research results, in the hybrid vehicle of the present invention, when exhaust gas recirculation is performed by the exhaust gas recirculation device, the exhaust gas recirculation is not performed with respect to the output power of the internal combustion engine for the same driving force requirement amount. Increased from time to time. As a result, the fuel efficiency of the internal combustion engine having the exhaust gas recirculation device can be further improved, and as a result, the energy efficiency of the hybrid vehicle including the internal combustion engine can be further improved. The increase in the output power of the internal combustion engine caused by increasing the output power of the internal combustion engine when exhaust recirculation is performed compared to when the exhaust gas recirculation is not performed can be used to drive the motor as a generator. In addition, the electric power generated by the electric motor can be used for charging the power storage device.

  Further, when exhaust gas recirculation is executed by the exhaust gas recirculation device, a required power that is a command value of power to be output to the internal combustion engine may be increased compared to when exhaust gas recirculation is not executed. As a result, when exhaust gas recirculation is executed, it is possible to increase the output power of the internal combustion engine for the same required driving force amount as compared to when exhaust gas recirculation is not executed.

  Further, the required power may be set based on at least the required traveling power required for traveling of the hybrid vehicle and the target charge / discharge power of the power storage device, and charging of the power storage device is required and When exhaust gas recirculation is executed by the exhaust gas recirculation device, charging of the power storage device is required, and the target charge / discharge power may be increased to the charging side as compared to when exhaust gas recirculation is not executed. Thus, when the exhaust gas recirculation is executed by the exhaust gas recirculation device, the required power is not executed when the exhaust gas recirculation is performed, while the fuel consumption of the internal combustion engine is not deteriorated by increasing the required power more than necessary. It becomes possible to increase more in comparison.

  Further, when charging of the power storage device is required and exhaust recirculation is not executed by the exhaust gas recirculation device, the target charge / discharge power is set to the first charging power and charging of the power storage device is required. When the exhaust gas recirculation is performed, the target charging / discharging power may be set to a second charging power that is larger as the charging power than the first charging power, and the first charging power is The electric motor is driven as a generator by at least a part of the power from the internal combustion engine in a state where the exhaust gas recirculation is not executed during the traveling of the hybrid vehicle, and the power storage device is forced by the electric power from the electric motor. The power actually output from the internal combustion engine when charging is from the internal combustion engine when the efficiency of the internal combustion engine is best when the exhaust gas recirculation is not executed. The second charging power may be determined to be included in a predetermined range centered on the power to be applied, and the internal combustion engine is in a state in which the exhaust gas recirculation is executed while the hybrid vehicle is traveling. The power actually output from the internal combustion engine when driving the electric motor as a generator by at least part of the motive power from the motor and forcibly charging the power storage device with electric power from the electric motor When the efficiency of the internal combustion engine becomes the best in a state in which is executed, it may be determined to be included in a predetermined range centered on the power output from the internal combustion engine. As a result, when charging of the power storage device is required, the power actually output from the internal combustion engine is output from the internal combustion engine when the efficiency of the internal combustion engine becomes the best regardless of the presence or absence of exhaust gas recirculation. Therefore, the fuel consumption of the internal combustion engine can be further improved.

  Further, the hybrid vehicle includes a first element connected to the rotation shaft of the electric motor, a second element connected to the drive shaft connected to the drive wheels, and a third element connected to the output shaft of the internal combustion engine. A planetary gear mechanism having an element and a second electric motor coupled to the second element may be provided.

  The hybrid vehicle includes a first element connected to a rotation shaft of a second electric motor different from the electric motor, a second element connected to a rotation shaft of the electric motor and an output shaft of the internal combustion engine, and a drive A planetary gear mechanism having a third element connected to a drive shaft connected to the wheel may be provided.

  In the hybrid vehicle, one end of the rotating shaft of the electric motor may be connected to the output shaft of the internal combustion engine, and the hybrid vehicle may include an input shaft connected to the other end of the rotating shaft of the electric motor. A continuously variable transmission having an output shaft coupled to the drive wheels may be provided.

The hybrid vehicle control method according to the present invention includes:
A driving force required amount by a driver comprising an internal combustion engine having an exhaust gas recirculation device, an electric motor capable of generating electric power using at least a part of power from the internal combustion engine, and a power storage device capable of exchanging electric power with the electric motor. In a control method of a hybrid vehicle that controls the internal combustion engine and the electric motor according to
When exhaust gas recirculation is executed by the exhaust gas recirculation device, the output power of the internal combustion engine for the same required driving force is increased as compared to when the exhaust gas recirculation is not executed.

  According to this method, it is possible to further improve the fuel efficiency of the internal combustion engine having the exhaust gas recirculation device, and to further improve the energy efficiency in the hybrid vehicle including the internal combustion engine.

1 is a schematic configuration diagram of a hybrid vehicle 20 that is a hybrid vehicle 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 at the time of engine operation performed by hybrid ECU70 of an Example. It is explanatory drawing which shows an example of the map for request | requirement torque setting. 4 is an explanatory diagram showing an example of an operation line of an engine 22. FIG. 3 is an explanatory diagram showing an example of a collinear diagram showing a dynamic relationship between the rotational speed and torque of a rotating element of the planetary gear 30 when the hybrid vehicle 20 travels. It is explanatory drawing which illustrates the relationship between the output power of the engine 22, and the net fuel consumption rate of the engine 22 at the time of non-execution of exhaust gas recirculation and execution. It is a flowchart which shows an example of the charging / discharging request | requirement power setting routine performed by battery ECU52 of an Example. It is explanatory drawing which shows an example of the map for charging / discharging request | requirement power setting. It is a schematic block diagram of the hybrid vehicle 20B which concerns on a modification.

  Next, the form for implementing this invention is demonstrated using an Example.

  FIG. 1 is a schematic configuration diagram of a hybrid vehicle 20 that is a hybrid vehicle according to an embodiment of the present invention. A hybrid vehicle 20 shown in FIG. 1 includes an engine (internal combustion engine) 22 that outputs power using a hydrocarbon fuel such as gasoline and light oil, and an engine electronic control unit (hereinafter referred to as “engine ECU”) that controls the engine 22. 24), a sun gear (first element) 31, a ring gear (second element) 32 connected to a ring gear shaft 32a as a drive shaft, and a plurality of pinion gears 33, and a crank of the engine 22 via a damper 28. A single-pinion planetary gear 30 having a planetary carrier (third element) 34 connected to a shaft (output shaft) 26, a motor MG1 connected to the sun gear 31 of the planetary gear 30 and mainly operating as a generator, and a reduction gear Ring gear via mechanism 35 and ring gear shaft 32a 2, a drive wheel 39a, 39b coupled to the ring gear shaft 32a via a gear mechanism 37 or a differential gear 38, inverters 41, 42 for driving the motors MG1, MG2, and an inverter 41 , 42 connected to the battery 50, which is a lithium ion secondary battery or a nickel hydride secondary battery, and a motor electronic control unit (hereinafter referred to as "motor ECU") that controls the motors MG1 and MG2 via the inverters 41, 42. 40), a battery electronic control unit (hereinafter referred to as “battery ECU”) 52 for managing the battery 50, and a hybrid electronic control unit for controlling the entire vehicle while communicating with the engine ECU 24, the motor ECU 40, the battery ECU 52, etc. (Hereafter, “Hybrid ECU” Say) and a 70.

  The engine 22 explosively burns a mixture of hydrocarbon-based fuel such as gasoline or light oil and air in the combustion chamber 120, and converts the reciprocating motion of the piston 121 accompanying the explosion combustion of the mixture into the rotational motion of the crankshaft 26. It is configured as an internal combustion engine that outputs power by converting. In this engine 22, as can be seen from FIG. 2, the air purified by the air cleaner 122 is taken into the intake pipe 126 through the throttle valve 123, and fuel such as gasoline is injected from the fuel injection valve 127 into the intake air. The The air / fuel mixture thus obtained is sucked into the combustion chamber 120 via an intake valve 131 driven by a valve mechanism 130 having a variable valve timing function and explosively burned by an electric spark from a spark plug 128. Be made. Exhaust gas from the engine 22 is an exhaust gas purification catalyst (three-way catalyst) that purifies harmful components such as carbon monoxide (CO), hydrocarbons (HC), and nitrogen oxides (NOx) through an exhaust valve 132 and an exhaust manifold 140. It is sent to the purification device 141 including 141c, purified by the purification device 141, and then discharged to the outside.

  The engine ECU 24 that controls the engine 22 configured as described above is configured as a microcomputer centering on a CPU (not shown). The engine ECU 24 receives signals from various sensors that are provided for the engine 22 and detect the operating state of the engine 22. For example, the engine ECU 24 includes a crank position from a crank position sensor 180 that detects the rotational position of the crankshaft 26, a cooling water temperature Tw from a water temperature sensor 181 that detects the temperature of cooling water in the engine 22, and a pressure in the combustion chamber 120. A cylinder position from a cylinder pressure sensor 182 that detects the rotational position of a camshaft included in a valve operating mechanism 130 that drives the intake valve 131 and the exhaust valve 132; The throttle position from the throttle valve position sensor 124 for detecting the position of the engine, the intake air amount Q from the air flow meter 183 for detecting the intake air amount as the load of the engine 22, and the intake air temperature sensor 184 attached to the intake pipe 126 Intake air temperature air, intake negative pressure Pi from the intake pressure sensor 185 for detecting the pressure (negative pressure) in the intake pipe 126, air-fuel ratio AF from the air-fuel ratio sensor 186 disposed upstream of the purification device 141 of the exhaust manifold 140, etc. Is input via an input port (not shown).

  The engine ECU 24 outputs various control signals for operating the engine 22 through an output port (not shown). For example, the engine ECU 24 controls the control signal to the throttle motor 125 that adjusts the position of the throttle valve 123, the control signal to the fuel injection valve 127, the control signal to the ignition coil 129 integrated with the igniter, and the valve mechanism 130. The control signal is output through the output port. Further, the engine ECU 24 calculates the rotational speed Ne of the engine 22 using the crank position from the crank position sensor 180. Further, the engine ECU 24 communicates with the hybrid ECU 70, controls the engine 22 based on signals from the hybrid ECU 70, and outputs data related to the operating state of the engine 22 to the hybrid ECU 70 as necessary.

  Further, as shown in FIG. 2, the engine 22 of the embodiment includes an EGR pipe 142 having one end connected to the exhaust pipe downstream of the purification device 141 and the other end connected to the intake pipe 126 (surge tank). An EGR valve 143 that is provided in the middle of the EGR pipe 142 and adjusts the recirculation amount of exhaust gas (EGR gas) recirculated from the exhaust system to the intake system via the EGR pipe 142, that is, the EGR amount (exhaust gas recirculation amount); An EGR device (exhaust gas recirculation device) 145 including a temperature sensor 144 that detects the temperature of the EGR gas in the EGR pipe 142 is provided. The EGR device 145 of the embodiment compares the EGR rate (= exhaust gas recirculation amount / (intake air amount + exhaust gas recirculation amount)) with, for example, 30 to 40% when performing exhaust gas recirculation (exhaust gas recirculation) via the EGR pipe 142. Highly configurable. As described above, the engine ECU 24 of the embodiment relatively moves from the exhaust system to the intake system when the vehicle speed V of the hybrid vehicle 20 is included in a predetermined medium vehicle speed range (for example, 40 to 100 km / h). The EGR valve 143 of the EGR device 145 is controlled so that the exhaust gas is recirculated at a high EGR rate.

  When the motor MG1 functions as a generator that generates power using at least a part of the power from the engine 22, the planetary gear 30 transmits the power from the engine 22 transmitted to the planetary carrier 34 to the sun gear 31 and the ring gear 32 at a gear ratio thereof. When the motor MG1 functions as an electric motor, the power from the engine 22 transmitted to the planetary carrier 34 and the power from the motor MG1 transmitted to the sun gear 31 are integrated and output to the ring gear 32. The power output to the ring gear 32 is finally output from the ring gear shaft 32a to the drive wheels 39a and 39b via the gear mechanism 37 and the differential gear 38.

  Motors MG1 and MG2 are configured as well-known synchronous generator motors, and exchange power with battery 50 through 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 either one of the motors MG1 and MG2 is supplied to the other. It can be consumed with the motor of. Therefore, the battery 50 is charged / discharged according to the electric power generated by the motors MG1, MG2, and is not charged / discharged if the balance of electric power is balanced between the motors MG1 and MG2.

  The motor ECU 40 is configured as a microcomputer centering on a CPU (not shown). The motor ECU 40 receives signals from rotational position detection sensors 43 and 44 that detect rotational positions of the rotors of the motors MG1 and MG2, phase currents applied to the motors MG1 and MG2 detected by a current sensor (not shown), and the like. The motor ECU 40 outputs a switching control signal to the inverters 41 and 42 and the like. Further, the motor ECU 40 calculates the rotational speeds Nm1 and Nm2 of the rotors of the motors MG1 and MG2 based on signals input from the rotational position detection sensors 43 and 44. Further, the motor ECU 40 communicates with the hybrid ECU 70 to drive and control the motors MG1 and MG2 based on signals from the hybrid ECU 70 and output data related to the states of the motors MG1 and MG2 to the hybrid ECU 70 as necessary.

  The battery ECU 52 is also configured as a microcomputer centering on a CPU (not shown). The battery ECU 52 includes a terminal voltage Vb from a voltage sensor (not shown) installed between terminals of the battery 50, and a charge / discharge current from a current sensor (not shown) installed in a power line 54 connected to the output terminal of the battery 50. Ib, the battery temperature Tb from the temperature sensor 51 installed in the battery 50, etc. are input. The battery ECU 52 communicates with the hybrid ECU 70 and the engine ECU 24, and outputs data relating to the state of the battery 50 to the hybrid ECU 70 and the engine ECU 24 as necessary. Further, the battery ECU 52 calculates the remaining capacity SOC indicating the charging rate of the battery 50 based on the integrated value of the charging / discharging current Ib detected by the current sensor, or the target charging / discharging power of the battery 50 based on the remaining capacity SOC. Charge / discharge required power Pb * (in the embodiment, the discharge side is positive and the charge side is negative) is calculated, or the battery 50 is allowed to be charged based on the remaining capacity SOC and the battery temperature Tb. An input limit Win as an allowable charging power that is electric power and an output limit Wout as an allowable discharge power that is allowable electric power for discharging the battery 50 are calculated.

  The hybrid ECU 70 is configured as a microcomputer centered on a CPU, and includes a ROM for storing various programs, a RAM for temporarily storing data, an input / output port and a communication port (not shown), and the like in addition to the CPU. As described above, the hybrid ECU 70 communicates with the engine ECU 24, the motor ECU 40, the battery ECU 52, and the like, and exchanges various signals and data with the engine ECU 24, the motor ECU 40, the battery ECU 52, and the like. Further, the hybrid ECU 70 includes a shift range SR from a shift range sensor 82 that detects an ignition signal from an ignition switch (start switch) 80, a shift range SR corresponding to an operation position (shift position) of the shift lever 81, and a driver. The brake pedal stroke sensor 86 detects the accelerator opening degree Acc from the accelerator pedal position sensor 84 that detects the depression amount (accelerator operation amount) of the accelerator pedal 83 as the driving force requirement amount by the brake pedal 85, and the depression amount of the brake pedal 85. The pedal stroke BS, the vehicle speed V from the vehicle speed sensor 87, and the like are input via the input port.

  In the hybrid vehicle 20 of the embodiment configured as described above, the required torque Tr * to be output to the ring gear shaft 32a as the drive shaft is calculated based on the accelerator opening Acc and the vehicle speed V, and this required torque Tr *. The engine 22, the motor MG1, and the motor MG2 are controlled so that torque corresponding to the torque is output to the ring gear shaft 32a. As a control mode for the engine 22, the motor MG 1, and the motor MG 2, the engine 22 is controlled so that power corresponding to the required torque Tr * is output from the engine 22, and all of the power output from the engine 22 is transmitted to the planetary gear 30. Torque conversion operation mode in which the motors MG1 and MG2 are driven and controlled so that torque is converted by the motors MG1 and MG2 and output to the ring gear shaft 32a, and the sum of the required torque Tr * and the power required for charging and discharging the battery 50 The engine 22 is controlled so as to be 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 caused by the planetary gear 30, the motor MG1, and the motor MG2. Requested torque Tr with torque conversion Charge / discharge operation mode in which the motors MG1 and MG2 are driven and controlled so that torque based on the torque is output to the ring gear shaft 32a, and the motor MG2 is configured to output the torque based on the required torque Tr * to the ring gear shaft 32a by stopping the engine 22. There are motor operation modes for driving control. Further, in the hybrid vehicle 20 of the embodiment, when a predetermined condition is satisfied under the torque conversion operation mode or the charge / discharge operation mode, intermittent operation for automatically stopping and starting the engine 22 is executed.

  Next, an operation when the above-described hybrid vehicle 20 travels in a state where the engine 22 is operated will be described. FIG. 3 shows a drive control during engine operation that is executed every predetermined time (for example, every several msec) by the hybrid ECU 70 of the embodiment when the accelerator pedal 83 is depressed by the driver while the engine 22 is operated. It is a flowchart which shows an example of a routine.

  At the start of the routine of FIG. 3, the CPU of the hybrid ECU 70 determines the accelerator opening Acc from the accelerator pedal position sensor 84, the vehicle speed V from the vehicle speed sensor 87, the rotational speeds Nm 1 and Nm 2 of the motors MG 1 and MG 2, and the charging of the battery 50. Input processing of data required for control such as required discharge power Pb * and input / output limits Win and Wout is executed (step S100). The rotational speeds Nm1 and Nm2 of the motors MG1 and MG2 are input from the motor ECU 40 through communication, and the charge / discharge request power Pb * and the input / output limits Win and Wout of the battery 50 are input from the battery ECU 52 through communication. After the data input process in step S100, the required torque Tr * to be output to the ring gear shaft 32a corresponding to the accelerator opening Acc and the vehicle speed V input in step S100 is derived from the required torque setting map illustrated in FIG. After setting, a required power Pe *, which is a command value of power to be output to the engine 22, is set (step S110). In the embodiment, the required power Pe * is the required travel power required for traveling of the hybrid vehicle 20, that is, the required torque Tr * required for travel, and the rotational speed Nr of the ring gear shaft 32a as the drive shaft (the rotational speed of the motor MG2). It is obtained by adding the loss Loss to a value obtained by subtracting the charge / discharge required power Pb * from the product of the gear ratio Gr of the Nm2 / reduction gear mechanism 35 or the vehicle speed V × conversion coefficient k).

  After the process of step S110, a target rotational speed Ne * and a target torque Te * as target operating points of the engine 22 are set based on the required power Pe * (step S120). In the embodiment, in order to set the target rotational speed Ne * and the target torque Te *, a predetermined operation line (optimum fuel consumption line) is prepared so as to operate the engine 22 efficiently. In step S120, A target rotational speed Ne * corresponding to the required power Pe * is derived and set from the operation line. FIG. 5 shows an example of the operation line of the engine 22. Then, the target torque Te * of the engine 22 is set by dividing the required power Pe * by the target rotational speed Ne * (step S120). Subsequently, using the target rotational speed Ne *, the rotational speed Nr of the ring gear shaft 32a (Nm2 / Gr or k · V) and the gear ratio ρ of the planetary gear 30 (the number of teeth of the sun gear 31 / the number of teeth of the ring gear 32) After calculating the target rotational speed Nm1 * of the motor MG1 according to the formula (1), the motor MG1 is calculated according to the following formula (2) using the target torque Te *, the target rotational speed Nm1 *, the current rotational speed Nm1 and the like of the engine 22. Torque command Tm1 * is set for (step S130). Expression (1) is a dynamic relational expression for the rotating element of the planetary gear 30 and is easily derived from a collinear diagram showing the dynamic relation between the rotational speed and the torque in the rotating element of the planetary gear 30 illustrated in FIG. It is what is done. Expression (2) is a relational expression in feedback control for rotating the motor MG1 at a target rotation speed Nm1 * corresponding to the target rotation speed Ne * of the engine 22, and the second term on the right side in the expression (2). “K1” is a gain of the proportional term, and “k2” of the third term on the right side is a gain of the integral term.

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

  If torque command Tm1 * for motor MG1 is set, output from motor MG2 using input / output limits Win and Wout of battery 50, torque command Tm1 * and current rotation speeds Nm1 and Nm2 of motors MG1 and MG2 Torque limits Tmin and Tmax as upper and lower limits of good torque are calculated according to the following equations (3) and (4) (step S140). Further, the temporary motor torque Tm2tmp, which is a temporary value of the torque to be output from the motor MG2, using the required torque Tr *, the torque command Tm1 *, the gear ratio ρ of the planetary gear 30 and the gear ratio Gr of the reduction gear mechanism 35 is Calculation is performed according to equation (5) (step S150). Then, the torque command Tm2 * for the motor MG2 is set to a value obtained by limiting the temporary motor torque Tm2tmp with the torque limits Tmin and Tmax (step S160). Thus, by setting the torque command Tm2 * for the motor MG2, the torque output to the ring gear shaft 32a can be limited within the range of the input / output limits Win and Wout of the battery 50. Equation (5) can be easily derived from the alignment chart of FIG.

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

  When torque commands Tm1 * and Tm2 * for motors MG1 and MG2 are set in this way, target engine speed Ne * and target torque Te * of engine 22 are transmitted to engine ECU 24, and torque commands Tm1 *, Tm2 * is transmitted to the motor ECU 40 (step S170), and this routine is temporarily terminated. The engine ECU 24 that has received the target rotational speed Ne * and the target torque Te * from the hybrid ECU 70 controls the intake air amount (opening control of the throttle valve 123) and fuel based on the target rotational speed Ne * and the target torque Te *. Injection control, ignition timing control, etc. are executed. The motor ECU 40 that has received the torque commands Tm1 * and Tm2 * from the hybrid ECU 70 switches 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 *. Switching control of the element is performed.

  Here, when the engine 22 is operated while the hybrid vehicle 20 is traveling and the vehicle speed V is included in the above-described middle vehicle speed range, the EGR valve of the EGR device 145 is configured so that the exhaust gas is recirculated from the exhaust system to the intake system. 143 is controlled, but as a result of earnest research on an engine having such an EGR device, the engine efficiency (net fuel consumption rate) becomes the highest when exhaust recirculation is not executed and when it is executed. It was found that the power output from the engine is different as shown in FIG. That is, when the engine efficiency (net fuel consumption rate) is the best when exhaust gas recirculation is not performed, the engine efficiency (net fuel consumption) when exhaust gas recirculation is performed is higher than the power Pe1 output from the engine. The power Pe2 (Pe2> Pe1) output from the engine when the rate is the highest is higher. In particular, the greater the amount of exhaust gas recirculated, the greater the tendency, and the difference between the power Pe1 and the power Pe2. That is, the difference in the range of power that can ensure good engine efficiency between when exhaust recirculation is not performed and when it is performed increases. Based on such research results, in the hybrid vehicle 20 of the embodiment, the charge / discharge required power Pb * used for calculating the required power Pe *, which is a command value of the power to be output to the engine 22, is not executed. In order to improve the fuel efficiency of the engine 22 by increasing the required power Pe * more appropriately when exhaust gas recirculation is executed by making the time different from when the exhaust gas is recirculated, compared to when exhaust gas recirculation is not performed. A charge / discharge required power setting routine illustrated in FIG. 8 is repeatedly executed by the ECU 52 every predetermined time.

  At the start of the routine of FIG. 8, the CPU of the battery ECU 52 executes input processing of data necessary for setting the charge / discharge required power Pb * such as the value of the EGR flag Fegr and the remaining capacity SOC of the battery 50 (step S200). The EGR flag Fegr is set to a value of 0 when the exhaust gas recirculation is not executed by the engine ECU 24 and set to a value of 1 when the exhaust gas recirculation is executed, and is input from the engine ECU 24 by communication. . After the data input process in step S200, it is determined whether exhaust gas recirculation is being executed by the EGR device 145 based on the value of the EGR flag Fegr (step S210). When the exhaust gas recirculation is not executed by the EGR device 145, a first charge / discharge required power setting that predetermines the relationship between the remaining capacity SOC and the charge / discharge required power Pb * when the exhaust gas recirculation is not executed. The charge / discharge required power Pb * corresponding to the remaining capacity SOC input in step S200 is derived and set from the map for use (step S220), and this routine is temporarily terminated. Further, when exhaust gas recirculation is being executed by the EGR device 145, a second charge / discharge required power setting for which the relationship between the remaining capacity SOC and the charge / discharge required power Pb * at the time of exhaust gas recirculation is determined in advance is used. The charge / discharge required power Pb * corresponding to the remaining capacity SOC input in step S200 is derived and set from the map (step S230), and this routine is temporarily terminated.

  FIG. 9 is an explanatory diagram illustrating a first charge / discharge required power setting map (see the broken line in the figure) and a second charge / discharge required power setting map (see the solid line in the figure). As shown in the figure, the first charge / discharge required power setting map used when exhaust gas recirculation is not executed is from the control center S0 (for example, 50%) in which the remaining capacity SOC is determined in advance to the control center S0. In the range up to a large predetermined value SH, the charge / discharge required power Pb * is set to a positive value (discharge power) that changes at a constant rate (change amount) corresponding to the change in the remaining capacity SOC. When the capacity SOC becomes equal to or higher than the predetermined value SH, the charge / discharge required power Pb * is set to a constant discharge power (positive value) Pd. Further, the first charge / discharge required power setting map shows the remaining charge / discharge required power Pb * when the remaining capacity SOC is in the range from the control center S0 to a predetermined forced charge start value SL (for example, 40%). A negative value (charging power) that changes at the above rate corresponding to the change in the capacity SOC is set, and when the remaining capacity SOC becomes equal to or lower than the forced charging start value SL, the charge / discharge request power Pb * is set to a constant first charging power. It is created so as to be set to (negative value) Pc1. In the embodiment, the first charging power Pc1 is generated by driving the motor MG1 as a generator by at least a part of the power from the engine 22 in a state where exhaust gas recirculation is not performed while the hybrid vehicle 20 is running. The power that is actually output from the engine 22 when the battery 50 is forcibly charged with electric power can be secured in a predetermined range centered on the power Pe1, that is, when the exhaust gas recirculation is not executed, so that the engine efficiency can be satisfactorily secured. It is determined through experiments and analysis so that it is included in the power range as much as possible.

  On the other hand, the second charge / discharge required power setting map used when exhaust gas recirculation is executed is the same as the first charge / discharge required power setting map when the remaining capacity SOC is in the range from the control center S0 to the predetermined value SH. The charge / discharge request power Pb * is set to a positive value (discharge power) that changes at the rate corresponding to the change in the remaining capacity SOC, and the first charge / discharge request is generated when the remaining capacity SOC becomes equal to or greater than the predetermined value SH. Similarly to the power setting map, the charge / discharge required power Pb * is created to be set to a constant positive value (discharge power) Pd. Further, the second charge / discharge required power setting map indicates that the charge / discharge required power Pb * is obtained when the remaining capacity SOC is in a range from the control center S0 to a predetermined forced charge start value SL ′ (SL ′ <SL). Is set to a negative value (charging power) that changes at the rate corresponding to the change in the remaining capacity SOC, and when the remaining capacity SOC falls below the forced charging start value SL ′, the charge / discharge required power Pb * is set to the first value. The constant second charging power (negative value) Pc2 is set to be smaller than the charging power Pc1. In the embodiment, the second charging power Pc2 is generated by at least a part of the power from the engine 22 in a state where exhaust gas recirculation is executed while the hybrid vehicle 20 is traveling (the vehicle speed V is included in the above-described middle vehicle speed range). When the MG1 is driven as a generator and the battery 50 is forcibly charged with the electric power from the motor MG1, the power actually output from the engine 22 is within a predetermined range centered on the power Pe2, that is, exhaust gas recirculation. It is determined through experiments and analysis so that it is included as much as possible within the power range that can ensure good engine efficiency during execution of the engine.

  By executing the charging / discharging required power setting routine of FIG. 8 using the first and second charging / discharging required power setting maps described above, in the hybrid vehicle 20 of the embodiment, the remaining capacity SOC becomes the forced charging start value SL. When the battery 50 is required to be charged and exhaust gas recirculation is executed by the EGR device 145, the remaining capacity SOC is equal to or less than the forced charging start value SL and the battery 50 is required to be charged and EGR is performed. Compared to when exhaust gas recirculation is not performed by the device 145, the charge / discharge required power Pb * is increased to the charge side. Therefore, when the remaining capacity SOC is equal to or less than the forced charging start value SL and charging of the battery 50 is requested and exhaust gas recirculation is executed by the EGR device 145, the required power Pe * for the engine 22 is equal to the remaining capacity SOC. Corresponds to the same accelerator opening degree Acc (and vehicle speed V), that is, the required torque Tr * when the EGR device 145 does not execute exhaust gas recirculation when the charging is not more than the forced charging start value SL. It is set so as to increase from the required power Pe * (step S110 in FIG. 3). That is, when the accelerator opening Acc (and the vehicle speed V) by the driver is the same, the required power Pe * (the output power of the engine 22) when the battery 50 is required to be charged and the exhaust gas recirculation is executed is Further, the required power Pe * when the battery 50 is required to be charged and the exhaust gas recirculation is not executed becomes larger. The engine 22 is operated at a target operating point (target rotational speed Ne * and target torque Te *) corresponding to the required power Pe * (and operation line), and a torque based on the required torque Tr * is used as a ring gear as a drive shaft. The engine 22 and the motors MG1 and MG2 are controlled so as to be output to the shaft 32a (steps S120 to S170 in FIG. 3).

  Thus, when charging of the battery 50 is required and exhaust gas recirculation by the EGR device 145 is not executed, the power Pe1 output from the engine 22 when the engine efficiency becomes the best without exhaust exhaust gas recirculation being executed. The engine 22 is operated so as to output power within a predetermined range centered. Further, when the battery 50 is required to be charged and the exhaust gas recirculation is executed by the EGR device 145, the power Pe2 output from the engine 22 when the engine efficiency becomes the best in the state where the exhaust gas recirculation is executed. Thus, the engine 22 is operated so as to output power within a predetermined range centering on. As a result, it is possible to further improve the fuel efficiency of the engine 22 having the EGR device 145 and to further improve the energy efficiency of the hybrid vehicle 20 including the engine 22. The increase in the output power of the engine 22 caused by increasing the required power Pe * of the engine 22 when exhaust gas recirculation is performed as compared with when exhaust gas recirculation is not performed is used to drive the motor MG1 as a generator. The increase in power generated by the motor MG1 can be used for charging the battery 50 or driving the motor MG2.

  As described above, in the hybrid vehicle 20 of the embodiment, when the exhaust gas recirculation is executed by the EGR device 145, the output power of the engine 22 with respect to the same accelerator opening Acc (and the vehicle speed V) is the exhaust gas recirculation. The required power Pe * of the engine 22 is set so as to increase compared to when it is not executed. As a result, the fuel efficiency of the engine 22 having the EGR device 145 can be further improved, and as a result, the energy efficiency of the hybrid vehicle 20 including the engine 22 can be further improved. The tendency that the power output from the engine 22 when the engine efficiency as described above becomes the highest is higher when the exhaust gas recirculation is executed than when the exhaust gas recirculation is not executed. In particular, it is particularly strong in a large displacement engine in which the EGR amount increases when the exhaust gas recirculation is executed even if the EGR rate is relatively low. Therefore, the present invention is extremely useful for an engine having a high EGR rate and a hybrid vehicle equipped with a large displacement engine having an EGR device.

  In the above embodiment, the required power Pe * is set based on the required travel power (= Tr * × Nr) required for the travel of the hybrid vehicle 20 and the charge / discharge required power Pb * of the battery 50. And when the exhaust gas recirculation is executed by the EGR device 145, the charge / discharge required power Pb * increases to the charge side as compared with the case where the battery 50 is required to be charged and the exhaust gas recirculation is not executed. Be made. As a result, the exhaust gas recirculation is executed when the exhaust gas recirculation is executed by the EGR device 145 while the fuel consumption of the engine 22 is not deteriorated by increasing the required power Pe * more than necessary. It becomes possible to increase more than when not. However, when charging of the battery 50 is requested and exhaust gas recirculation is executed instead of making the charge / discharge required power Pb * different, charging of the battery 50 is requested and exhaust gas recirculation is not executed. In comparison, the required power Pe * may be increased by a predetermined value.

  Further, in the above embodiment, when charging of the battery 50 is required and the exhaust gas recirculation is not executed by the EGR device 145, the charging / discharging required power Pb * is set to the first charging power Pc1 and the charging of the battery 50 is performed. When the exhaust gas recirculation is executed, the charge / discharge required power Pb * is set to the second charge power Pc2 that is larger than the first charge power Pc1. The first charging power Pc1 is driven by the electric power from the motor MG1 by driving the motor MG1 as a generator by at least a part of the power from the engine 22 in a state where exhaust gas recirculation is not performed while the hybrid vehicle 20 is running. The power actually output from the engine 22 when forcibly charging 50 is centered on the power Pe1 output from the engine 22 when the efficiency of the engine 22 is the best when exhaust gas recirculation is not executed. It is determined to be included within a predetermined range. Further, the second charging power Pc2 is generated by driving the motor MG1 as a generator by at least a part of the power from the engine 22 in a state where exhaust gas recirculation is executed while the hybrid vehicle 20 is running, and using the power from the motor MG1. The power Pe2 (Pe2) output from the engine 22 when the power actually output from the engine 22 when the battery 50 is forcibly charged becomes the highest in the efficiency of the engine 22 in a state where exhaust gas recirculation is executed. > Pe1) is determined to be included within a predetermined range. Thus, when the battery 50 is requested to be charged, the power actually output from the engine 22 is output from the engine 22 when the efficiency of the engine 22 becomes the highest regardless of the presence or absence of exhaust gas recirculation. Therefore, the fuel efficiency of the engine 22 can be further improved. In addition, since it is not necessary to change the operation line for setting the target operating point of the engine 22 between when exhaust recirculation is not executed and when it is executed, it is possible to reduce the burden required for adapting the operation line. .

  As described above, the exhaust gas recirculation is executed by the EGR device 145 instead of increasing the required power Pe * when the exhaust gas recirculation is executed by the EGR device 145 as compared with the case where the exhaust gas recirculation is not executed. Sometimes the target engine speed Ne * of the engine 22 is increased as compared to when the exhaust gas recirculation is not executed, or the throttle valve that is set based on the required power Pe * when the exhaust gas recirculation is executed by the EGR device 145 The target opening 123 may be increased as compared to when the exhaust gas recirculation is not executed. Further, the hybrid vehicle 20 of the above embodiment includes a sun gear 31 connected to the rotation shaft of the motor MG1, a ring gear 32 connected to the ring gear shaft 32a connected to the drive wheels 39a and 39b, and the crankshaft 26 of the engine 22. The planetary gear 30 having the planetary carrier 34 connected to the motor and the motor MG2 coupled to the ring gear 32 are included, but the configuration of the hybrid vehicle of the present invention is not limited to this. That is, instead of connecting the engine 22 and the motors MG1 and MG2 to the rotating element of the planetary gear 30 as described above, the rotating shaft of the motor MG2 is connected to the sun gear (first element) 31 of the planetary gear 30 and the ring gear (first gear). The rotation shaft of the motor MG1 and the crankshaft 26 of the engine 22 may be connected to the (two elements) 32, and the drive shaft connected to the drive wheels 39a and 39b may be connected to the planetary carrier (third element) 34. Furthermore, the present invention includes an engine (internal combustion engine) 22 having an EGR device 145, a motor MG connected to the crankshaft 26 of the engine 22, and an input shaft 61 (primary shaft) connected to the rotation shaft of the motor MG. And a mechanical continuously variable transmission (for example, a belt type CVT) 60 having an output shaft 62 coupled to the drive wheels 39a and 39b via the differential gear 38, and the motor MG for exchanging electric power via the inverter 45. 9 may be applied to a hybrid vehicle 20B shown in FIG. Further, instead of the reduction gear mechanism 35, for example, a transmission that changes the number of rotations of the motor MG2 having two speeds of Hi and Lo or three or more speeds and transmits it to the ring gear shaft 32a is adopted. May be.

  Here, the correspondence between the main elements of the embodiment and the main elements of the invention described in the column of means for solving the problems will be described. That is, in the above embodiment, the engine 22 corresponds to the “internal combustion engine”, the motors MG1 and MG that can generate power using at least a part of the power from the engine 22 correspond to the “electric motor”, and the motor MG1 and the electric power are supplied. The exchangeable battery 50 corresponds to “power storage means”, the planetary gear 30 corresponds to “planetary gear mechanism”, the motor MG2 corresponds to “second electric motor”, and the continuously variable transmission 60 corresponds to “continuously variable transmission”. Is equivalent to.

  However, the correspondence between the main elements of the embodiment and the main elements of the invention described in the column of means for solving the problem is the invention described in the column of means for solving the problem by the embodiment. Therefore, the elements of the invention described in the column of means for solving the problems are not limited. In other words, the examples are merely specific examples of the invention described in the column of means for solving the problem, and the interpretation of the invention described in the column of means for solving the problem is It should be done based on the description.

  As mentioned above, although the embodiment of the present invention has been described using examples, the present invention is not limited to the above-described examples, and various modifications can be made without departing from the scope of the present invention. Needless to say.

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

  20, 20B Hybrid vehicle, 22 engine, 24 electronic control unit (engine ECU) for engine, 26 crankshaft, 30 planetary gear, 31 sun gear, 32 ring gear, 32a ring gear shaft, 33 pinion gear, 34 planetary carrier, 39a, 39b drive wheel, 40 electronic control unit for motor (motor ECU), 41, 42, 45 inverter, 50 battery, 52 electronic control unit for battery (battery ECU), 54 power line, 60 continuously variable transmission, 61 input shaft, 62 output shaft, 70 Electronic control unit for hybrid (hybrid ECU), 142 EGR pipe, 143 EGR valve, 144 temperature sensor, 145 EGR device, MG1, MG2 motor.

Claims (8)

A driving force required amount by a driver comprising an internal combustion engine having an exhaust gas recirculation device, an electric motor capable of generating electric power using at least a part of power from the internal combustion engine, and a power storage device capable of exchanging electric power with the electric motor. In a hybrid vehicle that controls the internal combustion engine and the electric motor according to
A hybrid vehicle characterized in that when exhaust gas recirculation is executed by the exhaust gas recirculation device, the output power of the internal combustion engine with respect to the same required driving force is increased compared to when the exhaust gas recirculation is not executed. . The hybrid vehicle according to claim 1,
When exhaust gas recirculation is executed by the exhaust gas recirculation device, a required power that is a command value of power to be output to the internal combustion engine is increased compared to when the exhaust gas recirculation is not executed. vehicle. In the hybrid vehicle according to claim 1 or 2,
The required power is set based on at least the required travel power required for travel of the hybrid vehicle and the target charge / discharge power of the power storage device,
When charging of the power storage device is required and exhaust recirculation is executed by the exhaust gas recirculation device, the target charge / discharge is compared to when charging of the power storage device is required and exhaust gas recirculation is not executed. A hybrid vehicle characterized by increasing electric power to a charging side. In the hybrid vehicle according to claim 3,
When charging of the power storage device is required and exhaust recirculation is not executed by the exhaust gas recirculation device, the target charge / discharge power is set to the first charging power and charging of the power storage device is required. When the exhaust gas recirculation is performed, the target charging / discharging power is set to a second charging power that is larger than the first charging power as a charging power,
The first charging power is generated by driving the electric motor as a generator by at least a part of the power from the internal combustion engine in a state where the exhaust gas recirculation is not executed while the hybrid vehicle is running, and using the electric power from the electric motor. The power that is actually output from the internal combustion engine when the power storage device is forcibly charged is output from the internal combustion engine when the efficiency of the internal combustion engine is the best in a state where the exhaust gas recirculation is not performed. It is determined to be included within a predetermined range centered on power,
The second charging power is obtained by driving the electric motor as a generator by at least a part of the power from the internal combustion engine in a state where the exhaust gas recirculation is executed while the hybrid vehicle is running. The power actually output from the internal combustion engine when forcibly charging the power storage device is output from the internal combustion engine when the efficiency of the internal combustion engine is best in a state where the exhaust gas recirculation is executed. The hybrid vehicle is characterized in that it is determined to fall within a predetermined range centered on the power to be generated. In the hybrid vehicle according to any one of claims 1 to 4,
A planetary gear mechanism having a first element connected to a rotating shaft of the electric motor, a second element connected to a driving shaft connected to a driving wheel, and a third element connected to an output shaft of the internal combustion engine. When,
A hybrid vehicle further comprising a second electric motor coupled to the second element. In the hybrid vehicle according to any one of claims 1 to 4,
A first element connected to a rotating shaft of a second electric motor different from the electric motor; a second element connected to the rotating shaft of the electric motor and the output shaft of the internal combustion engine; and a driving shaft connected to driving wheels. And a planetary gear mechanism having a third element connected to the hybrid vehicle. In the hybrid vehicle according to any one of claims 1 to 4,
One end of the rotating shaft of the electric motor is connected to the output shaft of the internal combustion engine,
The hybrid vehicle further comprising a continuously variable transmission having an input shaft connected to the other end of the rotating shaft of the electric motor and an output shaft connected to the drive wheels. A driving force required amount by a driver comprising an internal combustion engine having an exhaust gas recirculation device, an electric motor capable of generating electric power using at least a part of power from the internal combustion engine, and a power storage device capable of exchanging electric power with the electric motor. In a control method of a hybrid vehicle that controls the internal combustion engine and the electric motor according to
A hybrid vehicle characterized in that when exhaust gas recirculation is executed by the exhaust gas recirculation device, the output power of the internal combustion engine with respect to the same required driving force is increased compared to when the exhaust gas recirculation is not executed. Control method.

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