JP2005053317A - Controller of hybrid automobile - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce engine fuel consumption while keeping driving stability of an automobile, in the four-wheel-drive type hybrid automobile of which first driving wheel is rotated by an engine and second driving wheel is rotated by an electric motor. <P>SOLUTION: According to longitudinal acceleration Aasp or the like of the automobile, the maximum front wheel driving force distribution rate Ffdmax and the minimum front wheel driving force distribution rate Ffdmin are set. In a driving force distribution range in between the Ffdmax and Ffdmin, the front wheel driving force distribution rate Ffds for minimizing the engine effective fuel consumption Fcon is realized, and vehicle body driving forces Tes, Tmas, and Tmbs outputted by the engine and a motor generator are set. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a control device for a hybrid vehicle, and more specifically, in a four-wheel drive hybrid vehicle in which a first drive wheel is rotated by an engine and a second drive wheel is rotated by an electric motor. The present invention relates to a technology for controlling driving force distribution between a wheel and a second driving wheel.

  There is known a four-wheel drive hybrid vehicle in which one of front wheels and rear wheels is rotated by an engine and the other is rotated by an electric motor. In this hybrid vehicle, there is no mechanical connection between the crankshaft of the engine and the output shaft of the electric motor, and the torque generated by each can be controlled independently. Further, in this hybrid vehicle, a generator that is operated by power from the engine is provided, and when the output of the engine has a margin, this generator is operated to generate electric power to be supplied to the battery of the electric motor.

The following are known as techniques for controlling the driving force distribution between the front wheels and the rear wheels of the four-wheel drive hybrid vehicle. That is, the engine fuel consumption is the highest by searching a map centering on the vehicle speed and the accelerator operation amount among the FF traveling mode by the engine, the RR traveling mode by the electric motor, and the four-wheel drive traveling mode by the engine and the electric motor. Select a driving mode that reduces. As a result, when the driving mode is changed and there is a possibility that the driving stability of the automobile is deteriorated when the driving mode is changed, the driving mode is changed to such a driving mode (for example, from the RR driving mode to the four-wheel drive). (Switching to the running mode) is prohibited (Patent Document 1).
JP 09-284911 (paragraph number 0052)

  However, the above technique has the following problems. In other words, in other words, in the setting of the driving force distribution, first, the driving power distribution corresponding to the travel mode in which the fuel consumption of the engine is the smallest is determined. When there is a possibility of deteriorating the driving stability, it can be said that the driving force distribution before such a fear occurs is adopted. For this reason, in the above technology, the driving force distribution adopted as a result when there is a possibility of deteriorating driving stability is obtained from the past vehicle speed or the like, and is not necessarily present from the viewpoint of fuel consumption. It is not suitable for driving conditions.

  The present invention relates to a four-wheel drive hybrid vehicle in which a first drive wheel is rotated by an engine and a second drive wheel is rotated by an electric motor, and the fuel consumption of the engine is maintained while maintaining the driving stability of the vehicle. It aims at further reducing.

  The present invention includes an engine that rotates a first drive wheel, an electric motor that rotates a second drive wheel that is different from the first drive wheel, and an output shaft that is mechanically independent from the crankshaft of the engine; Provided is a control device provided in a hybrid vehicle that includes a battery that stores electric power to be supplied to an electric motor and a generator that is operated by power from an engine to generate electric power to be supplied to the battery. The device according to the present invention is a driving force distribution range that is determined in accordance with a driving state or a driving condition of an automobile and that can take a driving force distribution between the first driving wheel and the second driving wheel. The driving force distribution for obtaining a predetermined fuel consumption amount of the engine is set, and the engine and the electric motor are controlled in accordance with the set driving force distribution.

  A control device for a hybrid vehicle according to an aspect of the present invention detects a driving state or a driving condition of a vehicle, and drives within a range in which a driving force distribution between the first driving wheel and the second driving wheel can be taken. A power distribution range is set based on the detected driving state or driving condition, and a driving power distribution that can obtain a predetermined fuel consumption of the engine is set in the set driving power distribution range, and according to the set driving power distribution. To control the engine and the electric motor.

  According to the present invention, a driving force distribution range corresponding to the traveling state of the automobile is determined, and a driving force distribution is set within which the predetermined fuel consumption of the engine is obtained. For this reason, in a four-wheel drive hybrid vehicle that uses an engine and an electric motor as power sources, the fuel consumption can be reduced to the maximum within a range in which the driving stability of the vehicle can be maintained.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 shows the configuration of a drive system 1 of a hybrid vehicle according to the first embodiment of the present invention. In the drawing, the mechanical force transmission path is indicated by a thick solid line, the power line is indicated by a dotted line, and the control line is indicated by a one-dot chain line.
The drive system 1 includes an engine 11, a motor generator 21 as a first electric motor, and a motor generator 12 as a second electric motor as power sources. The engine 11 is a spark ignition engine, and a direct injection type or a high fuel consumption type that delays the intake valve closing timing is adopted. The motor generators 21 and 12 can perform power running and regeneration, and a three-phase synchronous motor or a three-phase induction motor is employed. The crankshaft of the engine 11 and the output shaft of the motor generator 12 are integrally coupled, and the power output from the engine 11 and the motor generator 12 is transmitted through the torque converter 13 to the automatic transmission 14 and the differential gear 15. The left front wheel 17a and the right front wheel 17b, which are transmitted to the axles 16a and 16b and are attached to the axles as first drive wheels, are rotated. On the other hand, the power output from the motor generator 21 is transmitted to the axles 22a and 22b, and rotates the left rear wheel 23a and the right rear wheel 23b as second drive wheels attached to the axles. Electric power for operating motor generators 21 and 12 is stored in battery 31, and during powering operation, direct current output from battery 31 is converted into alternating current by inverter 32 and supplied to motor generators 21 and 12. The Further, during the regenerative operation, the alternating current output from the motor generators 21 and 12 is converted into a direct current by the inverter 32 and supplied to the battery 31. The battery 31 is a nickel metal hydride battery or a lithium ion battery. The inverter 32 employs a semiconductor device that can convert the alternating current output from the motor generators 21 and 12 into a direct current and convert the direct current output from the battery 32 into an alternating current.

  The engine 11 and the motor generators 21 and 12 are controlled by an electronic control unit (hereinafter referred to as “ECU”) 41 as an integrated controller. The ECU 41 includes a CPU, a ROM, a RAM, an interface circuit, and an inverter circuit, and switches the traveling mode of the vehicle according to the traveling state of the vehicle, the charging state of the battery 31, and the like. The travel modes include an FF travel mode using only the engine 11, an FF travel mode using only the motor generator 12, an FF travel mode using only the engine 11 and the motor generator 12, an RR travel mode using only the motor generator 21, and an engine 11 and a motor generator 21. A four-wheel drive travel mode and a four-wheel drive travel mode by the motor generator 12 and the motor generator 21 are included. The ECU 41 controls the ignition timing, the fuel injection amount, the intake air amount, and the like of the engine 11 and the power supply amount, the power generation amount, and the like of the motor generators 21 and 12 according to the travel mode. Further, in the four-wheel drive traveling mode, the ECU 41, based on the traveling state of the vehicle and the charged state of the battery 31, etc., improves the driving stability and traveling performance of the vehicle, and the rear wheels 23a and 17b. , 23b to control the distribution of driving force. Further, the ECU 41 controls the motor generator 12 to absorb the torque fluctuation of the engine 11 and the shift shock of the automatic transmission 14, and charges the battery 31 by causing the motor generators 21 and 12 to function as a generator. Control.

  The hybrid vehicle braking device includes motor generators 21 and 12 (which generate braking torque during regenerative operation) and wheel brakes 51 to 54. As the wheel brakes 51 to 54, for example, a disc brake is used that generates a braking force by pressing a pad against a disc fixed to a wheel rotation shaft. The ECU 41 switches between braking by only the wheel brakes 51 to 54 and braking by both the motor generators 21 and 12 and the wheel brakes 51 to 54 according to the state of charge of the battery 31.

  The ECU 41 includes a signal from the torque sensor 101 for detecting torque output from the engine 11, a signal from the current sensor 102 for detecting current input to the battery 31 or output from the battery 31, and wheels 17a, 17b, 23a. , 23b, a signal from the wheel speed sensors 103a to 103d, a signal from the accelerator sensor 104 for detecting the depression amount of the accelerator pedal, a signal from the brake sensor 105 for detecting the depression amount of the brake pedal, automatic shift A signal from a temperature sensor 106 that detects the hydraulic oil temperature of the machine 14 and a signal from an acceleration sensor 107 that detects accelerations in the longitudinal direction, the lateral direction, and the vertical direction of the automobile are input. The ECU 41 controls the engine 11 and the motor generators 21 and 12 based on various input signals. A piezoresistive sensor is used for the acceleration sensor 107.

Next, the operation of the ECU 41 will be described with reference to a flowchart.
FIG. 2 is a flowchart of the drive control routine. In this routine, the ratio of the vehicle body driving force to be borne by the front wheels 17a and 17b out of the total vehicle body driving force (hereinafter referred to as “front wheel driving force distribution ratio”) Ffd is controlled. In the following description, the vehicle driving force is treated as a positive value, the vehicle system power is treated as a negative value, and the larger the absolute value of both the vehicle body driving force and the vehicle system power, the greater the driving force or braking force. To do.

  In S101, the accelerator depression amount Ap, the vehicle speed Vasp, the longitudinal acceleration Aasp, and the battery storage amount Bsoc are read. The vehicle speed Vasp is expressed by a value obtained by averaging the rotational speeds of the wheels detected by the wheel speed sensors 51 to 54. The battery storage amount Bsoc is an indicator of the state of charge of the battery 31, and is represented by a value obtained by integrating the input / output currents of the battery 31.

In S102, the map shown in FIG. 3 is retrieved from the read Ap and Vasp, and a target value (hereinafter referred to as “target vehicle driving force”) Ta of the total vehicle driving force is set. In the table shown in FIG. 3, the target vehicle body driving force Ta is set to a larger value as the accelerator depression amount Ap is larger under a constant vehicle speed Vasp.
In S103, the table shown in FIG. 4 is retrieved from the read Aasp, and the maximum value (hereinafter referred to as “maximum front wheel driving force distribution ratio”) Ffdmax and minimum value (hereinafter referred to as “minimum”) that the front wheel driving force distribution ratio Ffd can take. It is referred to as “front wheel driving force distribution ratio.”) Ffdmin is set. The “driving force distribution range” is specified by the set Ffdmax and Ffdmin. The table shown in FIG. 4 is a front wheel that does not impair driving stability even with a general driver based on vehicle speed, longitudinal acceleration, body load distribution of front and rear wheels, and sensory evaluation by a test driver. A range of the driving force distribution rate Ffd is specified and created. For example, in an experiment or simulation, the longitudinal acceleration Aasp is changed at an appropriate interval, and the front wheel driving force distribution rate Ffd is changed between 0 and 1 under each Aasp. Then, the maximum value and the minimum value of the front wheel driving force distribution ratio Ffd that do not cause a side slip when a lateral wind in a range that can be assumed in normal driving or a lateral disturbance due to road surface unevenness are applied are respectively Ffdmax, Set to Ffdmin. In the table shown in FIG. 4, the maximum front wheel driving force distribution rate Ffdmax is set to a smaller value as the longitudinal acceleration Aasp is larger, and the minimum front wheel driving force distribution rate Ffdmin is larger as the longitudinal acceleration Aasp is larger. Is set.

The table of the maximum front wheel driving force distribution rate Ffdmax and the minimum front wheel driving force distribution rate Ffdmin employs the vehicle speed Vasp instead of the longitudinal acceleration Aasp, and causes a side slip with respect to a lateral disturbance under each Vasp. You may create by specifying Ffdmax and Ffdmin which have nothing.
In S104, the table shown in FIG. 5 is searched using the read Bsoc, and the motor effective fuel consumption rate Pconm is set. The motor effective fuel consumption rate Pconm is the amount of fuel Fm required to generate electric power corresponding to the power consumption when the motor generator 21 or the motor generator 12 or both of them function as a motor by the power from the engine 11. Is divided by the sum Wm of the work performed by the motor generators 21 and 12 that function as motors, and the calculated value is corrected by the battery storage amount Bsoc. Further, the engine fuel consumption rate Pcone is obtained by dividing the fuel consumption amount Fe of the engine 11 per unit time by the work amount We of the engine 11 performed by consuming this Fe. When the table shown in FIG. 5 is created, the maximum value Pcommax of the motor effective fuel consumption rate Pcomnm is set in correspondence with the value (= Bbmin + Bby) obtained by adding the damage prevention margin Bby of the battery 31 to the minimum value Bbmin of the battery storage amount Bsoc. To do. Further, the motor effective fuel consumption rate Pconm is made to correspond to a value (= Bbmax−Bby) obtained by subtracting the damage prevention margin Bby of the battery 31 from the maximum value Bbmax (corresponding to a fully charged state) of the battery storage amount Bsoc. A minimum value Pconmin is set. The characteristic of the motor effective fuel consumption rate Pconm with respect to the battery storage amount Bsoc is defined as a straight line having a negative slope connecting Pconmmax and Pconminmin. According to this characteristic, when the battery storage amount Bsoc is large, the fuel consumption amount by the motor generator 21 or the motor generator 12 is small, and when the battery storage amount Bsoc is small, the fuel consumption amount by the engine 11 is small. Become.

  In S105, the target engine drive that realizes the front wheel drive force distribution rate Ffd that minimizes the engine effective fuel consumption FCon in the drive force distribution range determined by the maximum front wheel drive force distribution rate Ffdmax and the minimum front wheel drive force distribution rate Ffdmin. The force Tes, the first target motor driving force Tmas, and the second target motor driving force Tmbs are set. The target engine driving force Tes is a vehicle body driving force to be borne by the engine 11, the first target motor driving force Tmas is a vehicle body driving force to be borne by the motor generator 21, and the second target motor driving force Tmbs is This is the vehicle body driving force to be borne by the motor generator 12. The engine effective fuel consumption amount FCon is a fuel consumption amount per unit time substantially consumed for operating the engine 11 and the motor generators 21, 12. The work amount of the engine 11 is defined as We, and the motor generator 21, The work amount of 12 is set as Wm and is calculated by the following formula (1).

Fcon = Pcon × We + Pcon × Wm (1)
Specifically, in each region in which the target vehicle body driving force Ta and the vehicle speed Vasp are partitioned at appropriate intervals, the front wheel driving force distribution rate Ffd is changed from 0 to 1, and the engine effective fuel is generated under each Ffd. A combination of the target engine driving force Tes and the second target motor driving force Tmbs that realizes the front wheel driving force distribution rate Ffd that minimizes the consumption amount FCon is specified. Such a process is performed for each region, and a table of engine effective fuel consumption FCon, target engine driving force Tes, and second target motor driving force Tmbs is created for each region. The first target motor driving force Tmas is determined as the product of the target vehicle body driving force Ta and the rear wheel driving force distribution ratio (= 1−Ffd). In actual driving, a corresponding region is specified by the target vehicle body driving force Ta and the vehicle speed Vasp, a table of engine effective fuel consumption FCon relating to the specified region is searched, and Fcon in the driving force distribution range (Ffdmin ≦ Ffd ≦ Ffdmax). The front wheel driving force distribution ratio Ffd that gives the minimum value FConmin is specified. Then, the table of the target engine driving force Te and the table of the second target motor driving force Tmb are searched, the target engine driving force Tes and the second target motor driving force Tmbs corresponding to the specified Ffd are specified, and the first 1 target motor driving force Tmas is determined.

In S106, the engine 11 is controlled according to the target engine driving force Tes, the motor generator 21 according to the first target motor driving force Tmas, and the motor generator 12 according to the second target motor driving force Tmbs.
FIGS. 6 to 8 show the tables of the engine effective fuel consumption amount FCon, the target engine driving force Te, and the second target motor driving force Tmb, which are set for a specific operation region, with different battery storage amounts Bsoc. ing. In each table, the first target motor driving force Tma (= Ta × (1−Ffd)) is also shown.

The table shown in FIG. 6 is for the case where the battery storage amount Bsoc is close to the lower limit value (= Bbmin + Bby) of the allowable range. In this case, the motor effective fuel consumption rate Pconm takes a large value, and the amount of fuel consumed by the engine 11 is smaller than that by the motor generators 21 and 12. Become.
The table shown in FIG. 7 is for the case where the battery storage amount Bsoc is close to the upper limit value (= Bbmax−Bby) of the allowable range. In this case, the motor effective fuel consumption rate Pconm takes a small value, and the motor generators 21 and 12 consume less fuel than the engine 11, so that both the motor generators 21 and 12 are always driven. It becomes distribution to do.

The table shown in FIG. 8 is for the case where the battery storage amount Bsoc is close to the middle value of the allowable range. In this case, since the motor generators 21 and 12 can be sufficiently charged and discharged, the target vehicle body driving force Ta is distributed to each of the engine 11 and the motor generators 21 and 12.
In the present embodiment, the longitudinal acceleration Aasp corresponds to the traveling state of the automobile, and S101 in the flowchart shown in FIG. 2 constitutes the traveling state detecting means. Further, S103 in the flowchart constitutes a driving force distribution range setting means, S104 and 105 in the flowchart constitute a driving force distribution setting means, and S106 in the flowchart constitutes a drive control means.

  According to the present embodiment, the maximum front wheel driving force distribution rate Ffdmax and the minimum front wheel driving force distribution rate Ffdmin corresponding to the longitudinal acceleration Aasp as the traveling state are set, and the driving force distribution specified by the set Ffdmax and Ffdmin In the range, the driving force distribution Ffds at which the engine effective fuel consumption amount FCon is minimized is set. For this reason, the fuel consumption can be minimized without departing from the range in which the driving stability of the automobile can be maintained.

6 to 8 show the case where the front wheel driving force distribution rate Ffds that gives the smallest engine effective fuel consumption FCon in the range from 0 to 1 is always within the driving force distribution range. When such a front wheel driving force distribution rate is outside the driving force distribution range, a front wheel driving force distribution rate that gives the smallest engine effective fuel consumption FCon within the driving force distribution range is set.
Other embodiments will be described below.

FIG. 9 shows a flowchart of a drive control routine according to the second embodiment of the present invention. The configuration of the drive system of the hybrid vehicle according to this embodiment is the same as that shown in FIG.
In this routine, in S201, the accelerator depression amount Ap, the vehicle speed Vasp, the longitudinal acceleration Aasp, the battery storage amount Bsoc, and the road surface friction coefficient Myu are read. The road surface friction coefficient Myu is expressed by the following equation (2) based on the target engine driving force Tes, the first motor driving force Tmas, the second target motor driving force Tmbs, the weight W of the automobile, the vehicle longitudinal acceleration Aasp, and the gravitational acceleration g. Detected as the calculated value by.

Myu = 1− (Tes + Tmas + Tmbs) / W + Aasp / g (2)
In S202, the map shown in FIG. 3 is retrieved from the read Ap and Vasp, and the target vehicle body driving force Ta is set.
In S203, the table shown in FIG. 4 is retrieved from the read Aasp, and the maximum front wheel driving force distribution rate Ffdmax and the minimum front wheel driving force distribution rate Ffdmin are set.

  In S204, the maximum front wheel driving force distribution rate Ffdmax and the minimum front wheel driving force distribution rate Ffdmin are corrected by the read Myu. The correction of Ffdmax is performed so as to decrease Ffdmax as the road surface friction coefficient Myu is smaller, and the correction of Ffdmin is performed so as to increase Ffdmin as the road surface friction coefficient Myu is smaller. A table that takes into account the road surface friction coefficient Myu may be set in advance, and the maximum front wheel driving force distribution rate Ffdmax and the minimum front wheel driving force distribution rate Ffdmin including a correction component by Myu may be set by searching this table. . The table in this case is a front wheel that does not impair driving stability even for ordinary drivers based on vehicle speed, longitudinal acceleration, body load distribution of front and rear wheels, road surface friction coefficient, sensory evaluation by test drivers, etc. The range of the driving force distribution rate Ffd can be specified and created. For example, in an experiment or simulation, the longitudinal acceleration Aasp and the road surface friction coefficient Myu are changed at appropriate intervals, and the front wheel driving force distribution ratio Ffd is changed between 0 and 1 under each Aasp and Myu. Then, the maximum value and the minimum value of the front wheel driving force distribution rate Ffd that do not cause a side slip when a lateral disturbance due to a side wind in a range that can be assumed in normal driving is applied are set to Ffdmax and Ffdmin, respectively. Further, the table of the maximum front wheel driving force distribution rate Ffdmax and the minimum front wheel driving force distribution rate Ffdmin may be created by adopting the vehicle speed Vasp instead of the longitudinal acceleration Aasp.

In S205, the table shown in FIG. 5 is searched using the read Bsoc, and the motor effective fuel consumption rate Pconm is set.
In S206, the target engine drive that realizes the front wheel drive force distribution rate Ffd that minimizes the engine effective fuel consumption FCon in the drive force distribution range determined by the maximum front wheel drive force distribution rate Ffdmax and the minimum front wheel drive force distribution rate Ffdmin. The force Tes, the first target motor driving force Tmas, and the second target motor driving force Tmbs are set.

In S207, the engine 11 and the motor generators 21 and 12 are controlled according to the set Tes, Tmas, and Tmbs.
In the present embodiment, the longitudinal acceleration Aasp corresponds to the traveling state of the vehicle, the road surface friction coefficient Myu corresponds to the traveling condition of the vehicle, and S201 of the flowchart shown in FIG. 9 constitutes the traveling state detection means. Further, S203 and 204 in the flowchart constitute driving force distribution range setting means, S205 and 206 in the flowchart constitute driving force distribution setting means, and S207 in the flowchart constitute driving control means.

According to the present embodiment, the maximum front wheel driving force distribution rate Ffdmax and the minimum front wheel driving force distribution rate Ffdmin are corrected by the road surface friction coefficient Myu, and the driving force distribution range is reduced with respect to the decrease in the road surface friction coefficient Myu. . For this reason, the driving stability of the automobile can be maintained and the fuel consumption can be reduced even when traveling on a frozen road or the like having a small road surface friction coefficient Myu.
FIG. 11 shows a flowchart of a drive control routine according to the third embodiment of the present invention. The configuration of the drive system of the hybrid vehicle according to this embodiment is the same as that shown in FIG.

In this routine, in step S301, the accelerator depression amount Ap, the vehicle speed Vasp, the longitudinal acceleration Aasp, the battery storage amount Bsoc, the road surface friction coefficient Myu, and the lateral acceleration yg are read. The lateral acceleration Yg is detected by the acceleration sensor 107.
In S302, the map shown in FIG. 3 is retrieved from the read Ap and Vasp, and the target vehicle body driving force Ta is set.

In S303, the table shown in FIG. 4 is searched from the read Aasp, and the maximum front wheel driving force distribution rate Ffdmax and the minimum front wheel driving force distribution rate Ffdmin are set.
In S304, the maximum front wheel driving force distribution rate Ffdmax and the minimum front wheel driving force distribution rate Ffdmin are corrected by the read Myu and Yg. The correction of Ffdmax is performed such that the smaller the road surface friction coefficient Myu and the lateral acceleration Yg are, the smaller the Ffdmax is. The correction of Ffdmin is performed when the road surface friction coefficient Myu is small and the lateral acceleration Yg is large. As shown, Ffdmin is increased. Note that a table in which the road surface friction coefficient Myu and the lateral acceleration Yg are taken into account is set in advance, and the maximum front wheel driving force distribution rate Ffdmax and the minimum front wheel driving force distribution rate Ffdmin including correction components based on Myu and Yg are searched by searching this table. You may make it set. In this case, the driving stability may be impaired even for ordinary drivers based on the vehicle speed, longitudinal and lateral acceleration, body load distribution of the front and rear wheels, road surface friction coefficient, sensory evaluation by a test driver, etc. It is possible to specify and create a range of the front wheel driving force distribution ratio Ffd without any. For example, in an experiment or a simulation, the longitudinal acceleration Aasp, the road surface friction coefficient Myu and the lateral acceleration Yg are changed at appropriate intervals, and the front wheel driving force distribution ratio Ffd is set to 0 to 1 under each Aasp, Myu, Yg. Vary between. Then, the maximum value and the minimum value of the front wheel driving force distribution rate Ffd that do not cause a side slip when a lateral disturbance due to a side wind in a range that can be assumed in normal driving is applied are set to Ffdmax and Ffdmin, respectively. Further, the table of the maximum front wheel driving force distribution rate Ffdmax and the minimum front wheel driving force distribution rate Ffdmin may be created by using the vehicle speed Vasp instead of the longitudinal acceleration Aasp.

In S305, the table shown in FIG. 5 is searched using the read Bsoc, and the motor effective fuel consumption rate Pconm is set.
In S306, the target engine drive that realizes the front wheel drive force distribution rate Ffd that minimizes the engine effective fuel consumption FCon in the drive force distribution range determined by the maximum front wheel drive force distribution rate Ffdmax and the minimum front wheel drive force distribution rate Ffdmin. The force Tes, the first target motor driving force Tmas, and the second target motor driving force Tmbs are set.

In S307, the engine 11 and the motor generators 21 and 12 are controlled according to the set Tes, Tmas, and Tmbs.
In the present embodiment, the longitudinal acceleration Aasp and the lateral acceleration Yg correspond to the traveling state of the vehicle, the road surface friction coefficient Myu corresponds to the traveling condition of the vehicle, and S301 in the flowchart shown in FIG. 11 constitutes the traveling state detection means. Further, S303 and 304 in the flowchart constitute driving force distribution range setting means, S305 and 306 in the flowchart constitute driving force distribution setting means, and S307 in the flowchart constitute driving control means.

  According to the present embodiment, the maximum front wheel driving force distribution rate Ffdmax and the minimum front wheel driving force distribution rate Ffdmin are corrected by the road surface friction coefficient Myu and the lateral acceleration Yg to reduce the road surface friction coefficient Myu and increase the lateral acceleration Yg. In contrast, the driving force distribution range was reduced. For this reason, it is possible to maintain the driving stability of the automobile and reduce the fuel consumption even when traveling on a frozen road or the like where the road surface friction coefficient Myu is small or when traveling on a curved road or the like where the lateral acceleration Yg is large. it can.

  In the above, the hybrid vehicle including both the motor generator 21 as the first electric motor and the motor generator 12 as the second electric motor has been described as an example. The present invention is not limited to this example, and can also be applied to a hybrid vehicle including only the motor generator 21, for example, as the first electric motor.

Configuration of drive system of hybrid vehicle according to first embodiment of the present invention Flow chart of drive control routine according to the embodiment Map of target body driving force Ta Table of maximum front wheel driving force distribution rate Ffdmax and minimum front wheel driving force distribution rate Ffdmin Table of motor effective fuel consumption rate Pconm Engine effective fuel consumption FConmin according to front wheel driving force distribution ratio Ffd when battery storage amount Bsoc is close to the allowable upper limit value Engine effective fuel consumption FConmin according to front wheel driving force distribution rate Ffd when battery storage amount Bsoc is close to the allowable lower limit value When the battery storage amount Bsoc is close to the intermediate value, the engine effective fuel consumption amount FConmin corresponding to the front wheel driving force distribution rate Ffd The flowchart of the drive control routine which concerns on the 2nd Embodiment of this invention. Driving force distribution range correction by road surface friction coefficient Myu Flowchart of a drive control routine according to the third embodiment of the present invention. Correction of driving force distribution range by road surface friction coefficient Myu and lateral acceleration Yg

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Drive system, 11 ... Engine, 12 ... Motor generator as 2nd electric motor, 13 ... Torque converter, 14 ... Automatic transmission, 15 ... Differential gear, 17a, 17b ... Front wheel as 1st drive wheel, DESCRIPTION OF SYMBOLS 21 ... Motor generator as 1st motor, 23a, 23b ... Rear wheel as 2nd driving wheel, 31 ... Battery, 32 ... Inverter, 41 ... Electronic control unit, 101 ... Engine torque sensor, 102 ... Input / output Current sensor, 103a to 103d ... wheel speed sensor, 104 ... accelerator sensor, 105 ... brake sensor, 106 ... hydraulic oil temperature sensor, 107 ... acceleration sensor.

Claims (9)

An engine for rotating the first drive wheel;
An electric motor having an output shaft mechanically independent of the crankshaft of the engine for rotating a second drive wheel different from the first drive wheel;
A battery for storing electric power supplied to the electric motor;
Provided in a hybrid vehicle configured to include a generator that generates power to be supplied to a battery by operating with power from an engine,
The predetermined fuel of the engine in a driving force distribution range that is determined in accordance with the driving state or driving condition of the automobile and that can be allocated to the driving force between the first driving wheel and the second driving wheel. A control device for a hybrid vehicle, which sets a driving force distribution for obtaining consumption and controls an engine and an electric motor in accordance with the set driving force distribution. An engine for rotating the first drive wheel;
A first electric motor having an output shaft that is mechanically independent of the crankshaft of the engine and rotates a second drive wheel different from the first drive wheel;
A battery for storing electric power to be supplied to the first electric motor;
Provided in a hybrid vehicle configured to include a generator that generates power to be supplied to a battery by operating with power from an engine,
Driving state detecting means for detecting the driving state or driving condition of the vehicle;
Driving force distribution range setting means for setting a driving force distribution range, which is a range that can be taken by the driving force distribution between the first driving wheel and the second driving wheel, based on the detected traveling state or traveling condition;
Driving force distribution setting means for setting a driving force distribution for obtaining a predetermined fuel consumption amount of the engine in the set driving force distribution range;
A control device for a hybrid vehicle, comprising: drive control means for controlling the engine and the first electric motor according to the set drive force distribution.   The hybrid vehicle control apparatus according to claim 2, wherein the driving force distribution range setting means detects a road surface friction coefficient and changes a driving force distribution range to be set according to the detected road surface friction coefficient.   4. The control apparatus for a hybrid vehicle according to claim 3, wherein the driving force distribution range setting means reduces the set driving force distribution range as the detected road surface friction coefficient is smaller.   5. The hybrid vehicle control apparatus according to claim 2, wherein the driving force distribution range setting means detects a lateral acceleration of the vehicle and changes a driving force distribution range to be set according to the detected lateral acceleration. .   6. The hybrid vehicle control device according to claim 5, wherein the driving force distribution range setting means reduces the set driving force distribution range as the detected lateral acceleration is larger.   7. The hybrid vehicle control device according to claim 2, wherein the driving force distribution setting unit detects a state of charge of the battery and sets the driving force distribution based on the detected state of charge.   The hybrid vehicle control apparatus according to any one of claims 2 to 7, wherein the driving force distribution setting means sets the driving force distribution at which the fuel consumption of the engine is minimized.   The hybrid vehicle includes a second electric motor that is different from the first electric motor and includes an output shaft connected to the crankshaft of the engine as a generator. The control apparatus of the hybrid vehicle in any one of Claims 2-8 which controls a 1st electric motor and a 2nd electric motor.

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