JP2002152913A - Changing control device for front- and rear-wheel-drive vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a charging control device for a front- and rear-wheel-drive vehicle, capable of obtaining electric power for driving an electric motor, without lacking or excess of amount, corresponding to the charging condition of a storage battery and the traveling condition of a vehicle, there by improving the fuel consumption. SOLUTION: An ECU 20 of the charging control device 1 for the front- and rear- wheel-drive vehicle 2 which drives front wheels 4 with an engines 3 through an automatic transmission 3a, and rear wheels 6 with the electric motor 5, detects a shift position POSI of the automatic transmission 3a, detects voltage VSBAT of electric power stored in an auxiliary battery 8, and detects remaining charging quantity SOC of a main battery 10 for driving the electric motor 5. When the shift position POSI of the automatic transmission 3a is in a non-traveling position (N or P), voltage VSBAT is at or more than prescribed voltage VSREF, and the remaining charging quantity SOC is less than a prescribed determined value UVON-SOC-L/H (when all determination results of steps 2, 4 and 5 are 'YES'), step-up conversion of electric power is carried out by a DC/DC converter 9, thus charging the main battery 10 with power which step-up conversion is carried out (step 7).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention controls a charging operation for storing electric power for driving an electric motor in a front and rear wheel drive vehicle in which one of front and rear driving wheels is driven by an engine and the other is driven by an electric motor. The present invention relates to a charge control device for a front and rear wheel drive vehicle.

[0002]

2. Description of the Related Art Heretofore, as a charge control device of this type, for example, one described in Japanese Patent Application Laid-Open No. H11-332012 is known. This front and rear wheel drive vehicle is of a type in which front wheels are driven by an engine and rear wheels are driven by an electric motor directly connected to the engine. This drive control device
A capacitor for storing electric power for driving the electric motor, an auxiliary battery for storing electric power for driving the starter motor, and a DC / DC converter for boosting the electric power of the auxiliary battery are provided. In this drive control device, when the electric power stored in the capacitor is used to drive the rear wheels during traveling, the electric power of the auxiliary battery is increased by D to compensate for the electric power.
The voltage is boosted by the C / DC converter and charged in the capacitor. In addition, when the vehicle is running at a reduced speed, the electric motor performs an electric power regenerating operation, and the regenerated electric power generated thereby charges the capacitor. Further, when the power of the accessory battery cannot be started due to a decrease in the power of the accessory battery due to a decrease in temperature or the like, the power of the accessory battery is boosted and the capacitor is charged. Then, the engine is started by driving the starter motor with the electric power charged in the capacitor.

[0003]

According to the above-described conventional charge control device, when the electric power of the capacitor is used during traveling, regardless of the operating state and the state of the auxiliary battery and the capacitor, Since the power of the battery is stepped up and the capacitor is always charged, the power cannot be charged to the capacitor in a fine and appropriate manner, and the power of the auxiliary battery may be insufficient. In addition, when the vehicle is stopped, charging of the capacitor is not performed except at the time of starting, so if the power amount of the capacitor is insufficient, the power amount for driving the electric motor at the time of starting is insufficient. In such a case, the driving force of the rear wheel by the electric motor is insufficient. Furthermore, since the electric motor and the rear wheel are directly connected to each other, when neither the driving of the rear wheel nor the power regeneration operation is performed, the electric motor becomes a running resistance on the contrary.
Fuel economy deteriorates.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an electric power for driving an electric motor can be obtained without excess or deficiency according to a state of charge of a storage battery or the like and a running state of a vehicle. It is an object of the present invention to provide a charge control device for a front and rear wheel drive vehicle that can improve fuel efficiency.

[0005]

In order to achieve this object, according to the first aspect of the present invention, one of the front and rear drive wheels (for example, a front wheel 4 in the embodiment (hereinafter the same in this section)) is automatically shifted. Front and rear wheel drive for controlling a charging operation for storing electric power for driving the electric motor 5 in a front and rear wheel drive vehicle 2 driven by the engine 3 via the motor 3a and driving the other (rear wheel 6) by the electric motor 5 A shift position detecting means (shift position sensor 25) for detecting the shift position POSI of the automatic transmission 3a, which is the charging control device 1 of the vehicle 2.
Power storage means (auxiliary battery 8) for storing power, voltage detection means (auxiliary battery voltage sensor 21) for detecting voltage VSBAT of power stored in the power storage means, and an electric motor 5 for driving electric motor 5. Motor power storage means (main battery 10) for storing power of a higher voltage than the power storage means, and power amount detection means (ECU 20, charge remaining amount) for detecting the amount of power (remaining charge SOC) stored in the motor power storage means Sensor 22), a boost converter (DC / DC converter 9) for boosting and converting the power supplied from the power storage means to charge the motor power storage means, and an automatic transmission 3a detected by the shift position detection means. The shift position POSI is at the non-traveling position (N or P position), and the voltage VSBAT of the power storage means detected by the voltage detection means is equal to the predetermined voltage V
When SREF or more and the electric energy (remaining charge SOC) of the motor power storage means detected by the electric energy detection means is less than a predetermined determination value UVON_SOC_L / H (all of the determination results in steps 2, 4 to 5). (When YES),
A charge control unit (ECU 20) for charging a motor power storage unit with the boosted power by causing the boost converter to perform boost conversion of power.

According to the charging control device for a front and rear wheel drive vehicle, the shift position detecting means detects the shift position of the automatic transmission, and the voltage detecting means detects the voltage of the electric power stored in the power storage means. The power amount stored in the motor power storage unit is detected by the power amount detection unit. Then, according to the detection results, when the shift position is in the non-traveling position, the voltage of the power storage means is equal to or higher than a predetermined voltage, and the electric energy of the motor power storage means is less than a predetermined determination value, the charge control means After the power of the power storage means is boost-converted by the boost converter, the power storage means for the motor is charged. In this manner, when the vehicle is stopped, when the voltage of the power of the power storage means is sufficient and the amount of power of the motor power storage means is insufficient, the power of the power storage means is boosted, unlike the related art,
The electric storage means for the motor is charged as electric power for driving the electric motor. As a result, a sufficient amount of power for driving the electric motor can be secured, and when starting the vehicle,
The other driving wheel can be driven with a sufficient driving force by the electric motor. In addition, by charging the power storage means for the motor only when the power of the power storage means is sufficient, the charging can be reliably performed while using the power without difficulty.

According to a second aspect of the present invention, there is provided a front and rear wheel drive vehicle 2 in which one of the front and rear drive wheels (front wheel 4) is driven by an engine 3 and the other (rear wheel 6) is driven by an electric motor 5. A charge control device 1 for a front and rear wheel drive vehicle 2 for controlling a charging operation for storing electric power for driving an electric motor 5, comprising a power storage means (auxiliary battery 8) for storing power, and an electric power stored in the power storage means. Voltage detecting means (auxiliary battery voltage sensor 21) for detecting the voltage VSBAT of the motor, a motor storage battery (main battery 10) for driving the electric motor 5, which stores higher power than the power storage means, and a motor storage battery. An electric energy detection means (ECU 20, remaining electric charge sensor 22) for detecting the stored electric energy (remaining charge SOC);
Temperature detecting means (main battery temperature sensor 23) for detecting the temperature TMBAT of the motor storage battery, and a boost converter (DC / DC converter 9) for boosting and converting the power supplied from the power storage means to charge the motor storage battery. When,
Voltage VSBA of power storage means detected by voltage detection means
The electric energy (remaining charge SOC) of the motor storage battery detected by the electric energy detection means when T is equal to or higher than the predetermined voltage VSREF.
Is less than the predetermined determination value UVON_SOC_L / H, and the temperature TM of the motor storage battery detected by the temperature detecting means.
When the BAT is equal to or lower than the predetermined temperature TMREF (when the determination results in steps 3 to 5 are all YES), the boost converter performs the boost conversion of the electric power.
Charge control means (ECU 20) for charging the power storage means for the motor with the boosted power.

According to the charging control device for a front and rear wheel drive vehicle, the voltage detecting means detects the voltage of the electric power stored in the electric storage means, and the electric energy detecting means detects the electric energy stored in the motor storage battery. The temperature of the motor storage battery is detected by the temperature detection means. Then, based on the detection results, when the voltage of the power storage means is equal to or higher than the predetermined voltage, the amount of power of the motor power storage means is lower than the predetermined determination value, and the temperature of the motor storage battery is equal to or lower than the predetermined temperature,
After the power of the power storage means is boost-converted by the boost converter by the charge control means, the power storage means for the motor is charged.
In this way, when the voltage of the power of the power storage means is sufficient, the amount of power of the power storage means for the motor is insufficient, and the temperature of the storage battery for the motor is low, that is, the storage battery for the motor is sufficiently activated. If the electromotive force is reduced due to the absence, the power of the power storage means is boosted and charged to the motor storage battery. As a result, due to the synergistic effect of the charging and the resulting increase in electromotive force due to the heat generated by the activation of the motor storage battery, the electric energy of the motor storage battery temporarily lowered due to the low temperature is reduced by the electric motor. It can be quickly restored to an amount sufficient to drive the other drive wheel. Thereby, the driving force of the electric motor for the other driving wheel can be sufficiently ensured.

On the other hand, in the invention according to claim 3, one of the front and rear drive wheels (front wheel 4) is driven by the engine 3, the other (rear wheel 6) is driven by the electric motor 5, and the other drive wheel ( In the front and rear wheel drive vehicle 2 in which the rear wheel 6) and the electric motor 5 are connected / disconnected by the clutch 12a, a charging operation for storing electric power for driving the electric motor 5 is performed by the electric operation while the front and rear wheel drive vehicle 2 is running. A charge control device 1 for a front-rear wheel drive vehicle 2 that controls including power regeneration by a motor 5, a clutch state detection means (clutch sensor 24) for detecting a connection / disconnection state of a clutch 12a, and a front-rear wheel drive vehicle 2 Traveling state detecting means (vehicle speed sensor 27) for detecting the traveling state (vehicle speed VP) of the vehicle, a power storage means (auxiliary battery 8) for storing electric power, and a higher electric power for driving electric motor 5 than the power storage means. Power storage means (main battery 10) for storing electric power of the motor, power amount detection means (ECU 20, charge remaining amount sensor 22) for detecting the amount of power (remaining charge SOC) stored in the motor power storage means, In accordance with a boost converter (DC / DC converter 9) for boosting and converting the electric power supplied from the power storage means to charge the power storage means, and a running state (vehicle speed VP) detected by the running state detection means. Regenerative electric energy estimating means (ECU for estimating regenerative electric energy SOC_RGN by motor 5)
20, step 15), the clutch state detecting means detects the disengaged state of the clutch 12a, and the running state detecting means detects that the front and rear wheel drive vehicle 2 is running,
And when the electric energy (remaining charge SOC) of the motor power storage means detected by the electric energy detection means is less than a predetermined electric energy (target remaining charge SOC_OBJ) (steps 9 and 13).
Is NO and the result of step 12 is YES
), Whether the boost conversion is performed by the boost converter based on the detected electric energy of the motor power storage means (remaining charge SOC) and the regenerative electric energy SOC_RGN estimated by the regenerative electric energy estimating means. Determining means (ECU 20, step 16) for determining whether or not to perform the step-up conversion, and executing the step-up conversion of the electric power by the step-up converter when the determination means determines the execution of the step-up conversion (when the determination result in step 16 is YES). Charging control means (ECU 20) for charging the boosted power to the power storage means for the motor
And the following.

According to the charging control device for a front and rear wheel drive vehicle, the clutch state detecting means detects the engaged / disengaged state of the clutch, the running state detecting means detects the running state, and the electric energy detecting means detects the running state. The amount of power stored in the motor power storage unit is detected, and the regenerative power amount estimated by the electric motor is estimated by the regenerative power amount estimation unit in accordance with the detected traveling state. Then, based on the detection result and the estimation result, the disengagement state of the clutch is detected, and it is detected that the front and rear wheel drive vehicle is running,
When the power amount of the motor power storage unit is less than the predetermined power amount, the determination unit performs the boost conversion of the power by the boost converter based on the power amount of the motor power storage unit and the estimated regenerative power amount. When the determination is made, the power of the power storage means is boost-converted by the boost converter by the charge control means, and then the motor power storage means is charged. As described above, when the vehicle is running only with the driving force of the engine and the electric energy of the electric power storage means for the motor is insufficient, the electric energy of the electric power storage means for the motor and the regeneration estimated to be obtained by the electric power regeneration Based on the amount of electric power, the charging is not performed by the electric power regeneration to the electric power storage means for the motor but by the boosting conversion of the electric power. Therefore, when the amount of regenerative power estimated to be obtained by power regeneration of the electric motor is insufficient, by performing charging by boosting conversion of the power, the amount of power of the motor power storage means is reduced by the electric motor to the other drive. It can be restored to an amount sufficient to drive the wheels. In addition, when driving by the electric motor is unnecessary, the electric motor can be prevented from becoming a running resistance by cutting off the electric motor and the driving wheels by the clutch, and the fuel efficiency can be improved accordingly.

Further, the invention according to claim 4 is the invention according to claim 3.
In the charging control device 1 of the front and rear wheel drive vehicle 2 described in
The determining means (ECU 20) determines the regenerative electric power SOC_R estimated from the electric energy (remaining charge SOC) of the motor power storage means.
Estimated electric energy to which GN is added (expected remaining charge SOC_ES
T) is the second predetermined electric energy (target remaining charge SOC_OBJ)
When it is less than (when the determination results in Steps 9 and 13 are NO and the determination results in Steps 12 and 16 are YES), the execution of the boosting conversion by the boosting converter is determined (Step 7), and the expected electric energy (estimated) Remaining charge SOC_E
ST) is equal to the second predetermined electric energy (target remaining charge SOC_OB)
J) or more (when the determination results in steps 9, 13, and 16 are NO and the determination result in step 12 is YES),
The execution of the power regeneration by the electric motor 5 is further determined (step 17), and when the execution of the power regeneration is determined by the determination means, the electric motor 5 is caused to execute the power regeneration, so that the regenerative power is stored in the motor power storage means. And a regenerative charge control means (ECU 20) for charging the battery.

According to this charging control apparatus for a front-rear wheel drive vehicle, when the determining means adds the estimated regenerative electric energy to the electric energy of the electric power storage means for the motor, the estimated electric energy is less than the second predetermined electric energy. Then, the execution of the boosting conversion of the power by the boosting converter is determined, whereby the charging control means executes the charging of the power storage means for the motor by the boosting conversion of the power. On the other hand, when the predicted electric energy is equal to or more than the second predetermined electric energy, the execution of the electric power regeneration by the electric motor is further determined, whereby the regenerative charging control means executes the electric power regeneration to charge the motor power storage means. You. As described above, during traveling with only the driving force of the engine, when the electric energy of the electric storage means for the motor is insufficient, when the estimated regenerative electric energy does not reach the target value, the charging by the boosting conversion of electric power is performed. When the regenerative electric energy is equal to or more than the target value, charging by electric power regeneration is executed respectively. Therefore, based on the regenerative electric energy estimated according to the traveling state of the front and rear wheel drive vehicle, it is possible to appropriately select charging by boost conversion of electric power or charging by electric power regeneration. Can be efficiently recovered to a sufficient amount of power.

On the other hand, in the invention according to claim 5, one of the front and rear drive wheels (front wheel 4) is driven by the engine 3, the other (rear wheel 6) is driven by the electric motor 5, and the other drive wheel ( In the front and rear wheel drive vehicle 2 in which the rear wheel 6) and the electric motor 5 are connected / disconnected by the clutch 12a, a charging operation for storing electric power for driving the electric motor 5 is performed by the electric operation while the front and rear wheel drive vehicle 2 is running. A charge control device 1 for a front-rear wheel drive vehicle 2 that controls including power regeneration by a motor 5, wherein a clutch state detection unit (clutch sensor 24) for detecting a connection / disconnection state of a clutch 12 a and the electric motor 5 are connected to each other. Motor driving state detecting means (ECU 20, step 14) for detecting whether or not the driving wheels are being driven;
A power storage means (auxiliary battery 8) for storing electric power, a motor power storage means (main battery 10) for driving electric motor 5 for storing electric power of a higher voltage than the power storage means, and a motor power storage means. Power detection means (ECU 20, remaining charge sensor 22) for detecting the amount of power (remaining charge SOC) and a boost converter for boosting and converting the power supplied from the power storage means to charge the motor power storage means (DC / DC converter 9), the clutch connection state detected by the clutch state detection unit, the motor drive state detection unit detecting that the electric motor 5 is being driven, and the motor amount detected by the power amount detection unit The power amount of the power storage means is less than the predetermined power amount (step 1).
Charge control means (ECU 20) for charging the boosted power to the motor power storage means by causing the boost converter to perform the boost conversion of the power when the determination results of 2 to 14 are YES). It is characterized by the following.

According to this charging control device for a front and rear wheel drive vehicle, the clutch connection state is detected by the clutch state detection means, and the electric motor is driving the other drive wheel by the motor drive state detection means. It is detected whether or not there is, and the power amount detection means detects the power amount stored in the motor power storage means. Then, based on these detection results, when the connection state of the clutch is detected, it is detected that the electric motor is driving the other drive wheel, and when the power amount of the motor power storage means is less than the predetermined power amount, After the power of the power storage means is boost-converted by the boost converter by the charge control means, the power storage means for the motor is charged. As described above, when the electric energy of the electric power storage means is insufficient and the electric motor is driving the other driving wheel, so that electric power cannot be regenerated by the electric motor, the boosting of the electric power is performed. Is performed, the shortage of the driving force due to the shortage of the electric power of the power storage means for the motor can be avoided during the front and rear wheel drive traveling of the front and rear wheel drive vehicle. In addition, when driving by the electric motor is unnecessary, the electric motor can be prevented from becoming a running resistance by cutting off the electric motor and the driving wheels by the clutch, and the fuel efficiency can be improved accordingly.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a charge control device for a front and rear wheel drive vehicle according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows a charge control device 1 according to the present invention.
1 shows a schematic configuration of a front and rear wheel drive vehicle (hereinafter, referred to as “vehicle”) 2 to which the invention is applied. As shown in the figure,
In this vehicle 2, left and right front wheels 4, 4 (one driving wheel) are driven by an engine 3, and left and right rear wheels 6, 6 (the other driving wheel) are driven by an electric motor (hereinafter referred to as "motor") 5. It is driven.

The engine 3 is mounted horizontally on the front of the vehicle 2 and has an automatic transmission 3a having a torque converter (not shown), a front differential gear mechanism 3b having a reduction gear (not shown), and left and right They are connected to left and right front wheels 4 and 4 via front drive shafts 3c and 3c. This automatic transmission 3a is composed of "1, 2, 3, D4, D5, N, R,
A shift lever (not shown) capable of selecting eight shift positions POSI consisting of "P" is provided. Further, the automatic transmission 3a is provided with a shift position sensor 25 (shift position detecting means) for detecting the shift position POSI. The shift position sensor 25 detects the selected shift position POSI, and outputs a detection signal of the selected shift position POSI to the ECU 2.
Send to 0.

The engine 3 is provided with an alternator 7. The alternator 7 generates electric power by being driven by the engine 3, and the generated electric power charges the auxiliary battery 8. The auxiliary battery 8 (power storage means) is for driving a starter motor or the like of the engine 3 and stores power at a predetermined voltage (for example, 12 V). The auxiliary battery 8 is connected to an auxiliary battery voltage sensor 21 as voltage detecting means. The auxiliary battery voltage sensor 21 detects the voltage VSBAT of the auxiliary battery 8 and sends a detection signal to the ECU 20.

Further, the auxiliary battery 8 has a DC / D
It is connected to a main battery 10 via a C converter 9. This DC / DC converter 9 (boost converter)
Is for boosting the power of the auxiliary battery 8 and charging the main battery 10, and the charging operation is controlled by the ECU 20 as described later. Hereinafter, the operation of boosting the power of the auxiliary battery 8 by the DC / DC converter 9 and charging the main battery 10 is referred to as “boost charging”.
That.

The main battery 10 (motor storage means, motor storage battery) drives the motor 5 and stores power at a predetermined voltage (for example, 144 V) higher than that of the auxiliary battery 8. This main battery 10 includes:
A remaining charge sensor 22 and a main battery temperature sensor 23 are provided. The remaining charge sensor 22 (power amount detecting means) detects a current / voltage value of the main battery 10 and sends a detection signal to the ECU 20. The ECU 20
Based on the detection signal of the remaining charge sensor 22, the remaining charge SOC (electric energy) of the main battery 10 is calculated. The remaining charge SOC is calculated as a ratio (%) of the electric energy currently stored in the main battery 10 to the electric energy when the main battery 10 is fully charged. Further, main battery temperature sensor 23 (temperature detecting means) detects temperature TMBAT of main battery 10 and outputs the detection signal to ETM.
Send to CU20.

On the other hand, the motor 5 is connected via a PDU 11 to a main battery 10 as a drive source. This P
The DU 11 is an electric drive circuit connected to the ECU 20. The operation of the DU 11 is controlled by the ECU 20 so that the electric power of the main battery 10 is supplied to the motor 5 to drive the rear wheel 6.

The motor 5 is connected to the left and right rear wheels 6 and 6 via a reduction gear mechanism 12 having a clutch 12a, a rear differential gear mechanism 13 and left and right rear drive shafts 14 and 14.
It is connected to. The clutch 12a is composed of, for example, a wet multi-plate clutch having an actuator (not shown) and capable of controlling the transmission capacity.
0, the motor 5 and the rear wheels 6, 6
Connect and disconnect between When the clutch 12a is connected and the motor 5 is driven by the power of the main battery 10, the rear wheels 6, 6 are driven, and at this time, the vehicle 2 enters the four-wheel drive state. The clutch 12a is not limited to a wet multi-plate clutch, but may be an electromagnetic clutch or the like.

Further, the reduction gear mechanism 12 is provided with a clutch sensor 24 as clutch state detecting means. The clutch sensor 24 detects the connection / disconnection state of the clutch 12a and sends a detection signal to the ECU 20.

The motor 5 is capable of regenerating electric power, and is controlled by the ECU 20 via the PDU 11 to be driven to rotate by the running energy of the vehicle 2.
This generates electricity. The regenerated power is charged in the main battery 10. Hereinafter, the operation of charging the main battery 10 with the electric power generated by the electric power regeneration of the motor 5 is referred to as “regenerative charging”.

Further, an accelerator opening sensor 26 and a vehicle speed sensor 27 are connected to the ECU 20. The accelerator opening sensor 26 detects an opening including on / off of an accelerator pedal (not shown) and sends a detection signal to the ECU 20. The vehicle speed sensor 27 (running state detecting means) detects a vehicle speed VP (a parameter indicating the running state) and sends a detection signal to the ECU 20.

The ECU 20 (power amount detecting means, charging control means, regenerative power amount estimating means, determining means, regenerative charging control means, motor driving state detecting means) includes a RAM, a ROM,
It is configured by a microcomputer (both not shown) including a CPU and an I / O interface. The ECU 20 controls the rotational driving of the motor 5 and the connection / disconnection of the clutch 12 a via the PDU 11 based on the detection signals from the various sensors 21 to 27, and furthermore, the DC / DC converter 9 to the main battery 10. And regenerative charging by the motor 5 are controlled.

Hereinafter, a charge control process for charging the main battery 10 with electric power will be described with reference to the flowchart of FIG. As will be described later, this process is for charging the main battery 10 by boosting charging during stoppage and selectively charging by boosting charging or regenerative charging during running when a predetermined condition is satisfied. Things.
This processing is performed for a predetermined time (for example, 100 msec).
It is executed every c).

First, in step 1 (shown as "S1"; the same applies hereinafter), it is determined whether or not an engine operation flag F_ENGON is "1". The engine operation flag F_ENGON is set to “1” while the engine 3 is operating,
It is set to “0” during stop. When the determination result is YES, that is, when the engine is operating,
Proceeding to step 2, it is determined whether the shift position is at the "N" or "P" non-traveling position.

If the result of this determination is YES, that is, if the shift position is at "N" or "P", the routine proceeds to step 3, where the main battery temperature TMBAT is reduced to the predetermined temperature TM.
It is determined whether the value is equal to or less than REF. This predetermined temperature TM
REF is the motor 5 because the main battery 10 is cold.
Is set to a value (for example, 0 ° C.) that may not be able to obtain sufficient electric power to drive. Note that the determination in step 3 may be performed using the temperature of the main battery estimated from the outside air temperature, the engine water temperature, or the like, instead of the main battery temperature TMBAT detected by the temperature sensor 23.

If the result of the determination in step 3 is YES, that is, if the main battery 10 is at a low temperature and there is a possibility that sufficient electric power to drive the motor 5 may not be obtained, the process proceeds to step 4 where the main battery 10 10 remaining charge SO
It is determined whether or not C is less than a predetermined determination value UVON_SOC_L / H. This predetermined determination value UVON_SOC_L
/ H is for determining whether or not the remaining charge SOC of the main battery 10 is sufficient, and is set to a value with hysteresis (for example, 50%, 55%) to stabilize the control. .

When the result of this determination is YES, that is, when the state of charge SOC of the main battery 10 is insufficient, the routine proceeds to step 5, where the voltage VSBA of the auxiliary battery 8 is
It is determined whether or not T is equal to or higher than a predetermined voltage VSREF.
This predetermined voltage VSREF is set as a lower limit (for example, 12 V) at which boost charging of main battery 10 can be performed with the power of auxiliary battery 8. When the result of this determination is YES, that is, when the power of the auxiliary battery 8 can execute the boost charging of the main battery 10, the process proceeds to step 6, where it is determined whether or not the accelerator-off flag F_APOFF is "1". I do.

This accelerator off flag F_APOFF
Is set to "1" when the accelerator pedal is not depressed,
It is set to "0" when being stepped on. When the determination result is YES, that is, when the accelerator pedal is not depressed, it is determined that the condition for executing the boosting charge to the main battery 10 is satisfied, and the process proceeds to step 7, and in order to indicate the condition, the boosting charge execution flag F_UVON is set. This is set to “1”, and this processing ends. This allows
In a boost charging control process (not shown), the main battery 10 is charged by boost charging.

On the other hand, if any of the determination results in steps 1 and 3 to 6 is NO, that is, whether the engine is stopped, whether the main battery temperature TMBAT is high, the remaining charge SOC of the main battery 10 is sufficient, Voltage VS of auxiliary battery 8
When the BAT is low or the accelerator pedal is depressed, it is determined that the condition for executing the boosting charge to the main battery 10 is not satisfied, and the process proceeds to Step 8, and the boosting charge execution flag F_UVON is set to “0” to indicate the condition. Is set, and this processing is ended.

On the other hand, if the decision result in the step 2 is NO, that is, if the shift position is in the traveling position such as the "D" position, the process proceeds to a step 9, and it is determined whether or not the vehicle is stopped. In this case, when the vehicle speed VP detected by the vehicle speed sensor 27 is equal to or less than a predetermined vehicle speed (for example, 5 km / h), it is determined that the vehicle is stopped. If the result of this determination is NO, that is, if the vehicle is running, the routine proceeds to step 10, where the friction coefficient μ of the road surface is estimated. The estimation of the frictional resistance coefficient μ is executed based on the vehicle speed VP by a known calculation method, although a specific description is omitted.

Next, the process proceeds to step 11 and proceeds to step 10
Friction coefficient μ and main battery temperature TMBAT
The target remaining charge SOC_OBJ is calculated by searching a map whose example is shown in FIG. As shown in the figure, this map shows the first to third values of the frictional resistance coefficient μ.
And the main battery temperature TM
BAT first and second predetermined boundary values TMB1, TMB2
, And a target remaining charge SOC_OBJ (predetermined power amount, second predetermined power amount) is set corresponding to each region. In particular,
In a region where the frictional resistance coefficient μ is smaller than the third boundary value μ3, the target remaining charge SOC_OBJ is set to a larger value as the frictional resistance coefficient μ is smaller. This is because the smaller the frictional resistance coefficient μ, the higher the frequency of traveling in the four-wheel drive state.

On the other hand, in the region where the frictional resistance coefficient μ is larger than the third boundary value μ3, the target remaining charge SOC_OBJ is larger than the region between the third boundary value μ3 and the second boundary value μ2 smaller than this. Is set to a large value. This is because, in the region where the frictional resistance coefficient μ is larger than the third boundary value μ3, the frequency of traveling in the four-wheel drive state is extremely low, so that regenerative charging can be easily performed, thereby easily securing a large power generation amount. by.

The frictional resistance coefficient μ is equal to a predetermined boundary value μ1.
(<Μ2), the main battery temperature TM
As the BAT is lower, the target remaining charge SOC_OBJ is set to a larger value. This is the main battery temperature T
This is because the lower the MBAT, the lower the electromotive force of the main battery 10, which is to compensate for it. Further, when the frictional resistance coefficient μ and the main battery temperature TMBAT match respective boundary values, the target remaining charge SOC_OBJ is set to a value in a region to which these belonged before. Note that the target remaining charge SOC_OBJ calculated as described above is used.
May be corrected based on the outside air temperature. Furthermore, the target remaining charge SOC_OBJ may be calculated using the outside air temperature as a parameter instead of the frictional resistance coefficient μ or together with the frictional resistance coefficient μ. This is because when the outside air temperature is low, road surface freezing and the like are likely to occur, and it is estimated that the frequency of traveling in the four-wheel drive state increases.

Next, the routine proceeds to step 12, where it is determined whether or not the current state of charge SOC is less than the target state of charge SOC_OBJ. If the result of this determination is YES, that is, if the state of charge SOC is insufficient, step 13
Then, it is determined whether or not the clutch 12a is on (connected).

When the result of this determination is YES, that is, when the clutch 12a is in the engaged state, the routine proceeds to step 14, where it is determined whether or not the motor 5 is driving the rear wheels.
When the determination result is YES, that is, when the rear wheels are being driven, regenerative charging cannot be performed.
Is performed to perform the boost charging, and the process ends. Instead of determining whether the vehicle is being driven by the rear wheels in step 14, it may be determined whether the vehicle is cruising in a predetermined vehicle speed range. In this way, boosting charging can be performed even in an operating state in which torque required of motor 5 is small and regenerative charging cannot be performed during cruising travel.

On the other hand, if the decision result in the step 13 is NO, that is, if the clutch 12a is in the disengaged state, the routine proceeds to a step 15, in which a table (not shown) is searched based on the vehicle speed VP, so that the regenerative electric energy SOC_RGN
Is calculated. This regenerative electric energy SOC_RGN is an electric energy estimated to be obtained when the electric power regeneration is executed until the current vehicle speed VP is reduced to the predetermined vehicle speed.

Next, the routine proceeds to step 16, where the estimated charge amount S
It is determined whether or not OC_EST is smaller than target remaining charge SOC_OBJ. This expected charge amount SOC_EST (expected power amount) is a value obtained by adding the regenerative power amount SOC_RGN calculated in step 15 to the current remaining charge amount SOC.

When the result of this determination is YES, that is, when it is estimated that the total remaining charge SOC obtained by executing the regenerative charging does not reach the target remaining charge SOC_OBJ (in the state shown in FIG. 4). Proceeds to step 7 to execute boost charging, and ends this processing. On the other hand, when the determination result is NO, that is, when it is estimated that the total remaining charge SOC obtained by executing the regenerative charging is equal to or more than the target remaining charge SOC_OBJ,
Proceed to step 17 to execute the power regeneration execution flag F_MOTR
After setting GN to "1", the above-mentioned step 8 is executed, and this processing is ended. Thus, in the power regeneration control process (not shown), the main battery 10 is charged by regenerative charging. In step 16, the target remaining charge SOC_ is compared with the expected charge SOC_EST.
Although the same value as in step 12 is used as OBJ, the present invention is not limited to this, and a different value may be used.

On the other hand, if the determination result in any of steps 9, 12, and 14 is NO, that is, if the vehicle is stopped, the remaining charge SOC is sufficient, or the rear wheels are not driven, the boost charging is performed. If it should not be executed, the above step 8 is executed, and this processing is ended.

As described above, according to the charging control device 1 of the present embodiment, the shift position POSI is in the non-traveling position,
When the voltage of the auxiliary battery 8 is sufficient and the remaining charge SOC of the main battery 10 is insufficient, the boosting charge is executed, so that a sufficient amount of power for driving the motor 5 can be ensured. When the vehicle starts, the rear wheel 6 can be driven by the motor 5 with a sufficient driving force. Further, by performing the charging only when the voltage of the auxiliary battery 8 is sufficient, it is possible to reliably perform the boost charging while using the power without difficulty.

Further, in addition to the above conditions, the main battery 1
Since the temperature TMBAT of 0 is low, the boosting charge is executed when the electromotive force is decreasing. Therefore, the electromotive force increases due to the boosting charge and the accompanying heat generated by the activation of the main battery 10. Of the main battery 10 temporarily decreased due to the low temperature due to the synergistic effect of
C can be quickly recovered to a sufficient amount.

If the state of charge SOC of the main battery 10 is insufficient during traveling, the regenerative electric power SOC estimated to be obtained by regenerative charging while the clutch 12a is disconnected.
_RGN is not sufficient, boost charging is performed, and regenerative power SO
Since the regenerative charging is selected and executed when C_RGN is sufficient, the remaining charge SOC of the main battery 10 can be efficiently recovered to a sufficient amount. On the other hand, the motor 5
When the motor 5 is not driven, the clutch 12a cuts off the connection between the motor 5 and the rear wheel 6 so that the motor 5
Can be prevented from becoming a running resistance, and the fuel efficiency can be improved accordingly.

Further, when the vehicle is running and the rear wheel 6 is being driven by the motor 5 while the state of charge SOC of the main battery 10 is insufficient, the regenerative charging cannot be executed. Is executed, it is possible to avoid a shortage of driving force due to a shortage of the remaining charge SOC of the main battery 10 during traveling.

The present invention is not limited to the front and rear wheel drive vehicle 2 of the embodiment in which the front wheels 4 and 4 are driven by the engine 3 and the rear wheels 6 and 6 are driven by the motor 5, respectively. That is, the present invention may be applied to a front and rear wheel drive vehicle in which a rear wheel and a front wheel are driven by an engine and a motor, respectively. Further, the configuration for storing electric power for driving the motor 5 is not limited to the main battery 10 of the embodiment, but may be any configuration that can store electric power such as a capacitor.

[0048]

As described above, according to the charging control apparatus for a front and rear wheel drive vehicle of the present invention, it is possible to secure a sufficient amount of electric power for driving the electric motor. Thus, the other driving wheel can be driven with a sufficient driving force. In addition, by charging the power storage means for the motor only when the power of the power storage means is sufficient, the charging can be reliably performed while using the power without difficulty.

Also, due to the synergistic effect of charging and the resulting increase in electromotive force due to heat generated by activation of the motor storage battery, the electric energy of the motor storage battery temporarily reduced due to the low temperature is converted into an electric power. The motor can quickly recover to an amount sufficient to drive the other drive wheel.
Thereby, the driving force of the electric motor for the other driving wheel can be sufficiently ensured.

Further, when the amount of regenerative power estimated to be obtained by power regeneration of the electric motor is insufficient, charging by boosting conversion of power is performed to reduce the amount of power of the motor power storage means. The motor can be restored to an amount sufficient to drive the other drive wheel. In addition, when driving by the electric motor is unnecessary, the electric motor can be prevented from becoming a running resistance by cutting off the electric motor and the driving wheels by the clutch, and the fuel efficiency can be improved accordingly. In addition, based on the regenerative electric energy estimated according to the traveling state of the front and rear wheel drive vehicle, it is possible to appropriately select charging by boost conversion of the electric power or charging by electric power regeneration, whereby the electric energy of the electric storage means for the motor can be selected. Can be efficiently recovered to a sufficient amount of power.

Further, based on the amount of regenerative electric power estimated according to the running state of the front and rear wheel drive vehicle, it is possible to appropriately select charging by boost conversion of electric power or charging by electric power regeneration. Can be efficiently recovered to a sufficient amount of power.

Further, when the electric power of the electric power storage means is insufficient and the electric motor cannot drive the electric power because the other driving wheel is being driven by the electric motor, the electric power is boosted. Since the charging of the motor storage battery is performed by the conversion, it is possible to avoid a shortage of driving force due to a shortage of electric power of the motor power storage means during front and rear wheel drive traveling of the front and rear wheel drive vehicle.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a charge control device according to an embodiment of the present invention and a front and rear wheel drive vehicle to which the charge control device is applied.

FIG. 2 is a flowchart showing a charge control processing routine executed by the charge control device.

FIG. 3 is a diagram showing an example of a map used for calculating a target remaining charge.

FIG. 4 shows a current remaining charge, a regenerative electric energy, an expected remaining charge,
FIG. 4 is an explanatory diagram showing an example of a relationship between a target remaining charge amount and a boosted charge amount by a DC / DC converter.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Charge control device 2 Front and rear wheel drive vehicle 3 Engine 3a Automatic transmission 4 Left and right front wheels (one drive wheel) 5 Electric motor 6 Left and right rear wheels (the other drive wheel) 8 Auxiliary battery (power storage means) 9 DC / DC converter (step-up converter) 10 Main battery (motor power storage means, motor storage battery) 12a Clutch 20 ECU (power amount detection means, charge control means, regenerative power amount estimation means, determination means, regenerative charge control means, motor drive state Detecting means) 21 auxiliary battery voltage sensor (voltage detecting means) 22 remaining charge sensor (power amount detecting means) 23 main battery temperature sensor (temperature detecting means) 24 clutch sensor (clutch state detecting means) 25 shift position sensor (shift) Position detecting means) 27 Vehicle speed sensor (running state detecting means) POSI shift position SOC Remaining charge (power SOC_UVON_L / H Predetermined judgment value SOC_OBJ Target remaining charge (predetermined power, second predetermined power) SOC_RGN Regenerative power SOC_EST Expected remaining charge (predicted power) TMBAT Main battery temperature (temperature of motor storage battery) TMREF Predetermined temperature VSBAT Voltage of auxiliary battery (voltage of power storage means) VSREF Predetermined voltage VP Vehicle speed (parameter indicating running state)

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H02J 7/00 H02J 7/00 303C 303 B60K 9/00 E (72) Inventor Naoki Uchiyama Wako City, Saitama 1-4-1 in Honda R & D Co., Ltd. (72) Inventor Takashi Nakasako 1-4-1 in Chuo Wako-shi, Saitama Pref. In Honda R & D Co., Ltd. (72) Naohiro Yonekura inventor Chuo in Wako-shi, Saitama 1-4-1 F-term in Honda R & D Co., Ltd. F-term (reference) QE01 QI04 SE03 SE05 SE06 TI02 TI10 TO05 TO12 TO13

Claims (5)

[Claims] In a front-wheel drive vehicle in which one of front and rear drive wheels is driven by an engine via an automatic transmission and the other is driven by an electric motor, a charging operation for storing electric power for driving the electric motor is performed. A charge control device for a front and rear wheel drive vehicle to be controlled, comprising: a shift position detecting means for detecting a shift position of the automatic transmission; a power storage means for storing power; and a voltage of the power stored in the power storage means. Voltage detecting means, for driving the electric motor, a power storage means for a motor that stores power of a higher voltage than the power storage means, and a power amount detection means for detecting the amount of power stored in the power storage means for the motor A boost converter for boosting and converting the power supplied from the power storage means in order to charge the motor power storage means; and the self-power converter detected by the shift position detection means. The shift position of the transmission is at the non-traveling position, the voltage of the power storage means detected by the voltage detection means is equal to or higher than a predetermined voltage, and the electric energy of the motor power storage means detected by the electric energy detection means is When it is less than the predetermined judgment value,
Charge control means for causing the boost converter to perform the boost conversion of electric power to charge the boosted power to the motor power storage means. apparatus. 2. A front-rear wheel drive vehicle in which one of front and rear drive wheels is driven by an engine and the other is driven by an electric motor, wherein the front-rear wheel drive vehicle controls a charging operation for storing electric power for driving the electric motor. A power storage means for storing power, a voltage detection means for detecting a voltage of the power stored in the power storage means, and a voltage higher than the power storage means for driving the electric motor. A motor storage battery that stores electric power, an electric energy detection unit that detects an amount of electric power stored in the motor storage battery, a temperature detection unit that detects a temperature of the motor storage battery, and a battery for charging the motor storage battery. A boost converter for boosting and converting the power supplied from the power storage means; and a voltage of the power storage means detected by the voltage detection means being equal to or higher than a predetermined voltage, When the electric energy of the motor storage battery detected by the detection means is less than a predetermined determination value and the temperature of the motor storage battery detected by the temperature detection means is equal to or lower than a predetermined temperature, the boost converter By performing the step-up conversion of
Charge control means for charging the power storage means for the motor with the boosted power, a charge control device for a front-rear wheel drive vehicle. 3. A front and rear wheel drive vehicle in which one of front and rear drive wheels is driven by an engine, the other is driven by an electric motor, and the other drive wheel and the electric motor are connected and disconnected by a clutch. A charge control device for a front-rear wheel drive vehicle that controls a charging operation for storing electric power for driving the electric motor, including power regeneration by the electric motor during travel of the front-rear wheel drive vehicle, A clutch state detecting means for detecting a connected / disconnected state, a running state detecting means for detecting a running state of the front and rear wheel drive vehicle, a power storage means for storing electric power, and a power storage means for driving the electric motor. Power storage means for storing electric power of a very high voltage; power amount detection means for detecting the amount of power stored in the motor power storage means; and the motor power storage means A boost converter for boosting and converting the power supplied from the power storage means, and a regenerative power amount for estimating a regenerative power amount by the electric motor in accordance with a traveling state detected by the traveling state detection means. The estimating means, the clutch state detecting means detects a disengaged state of the clutch, the running state detecting means detects that the front and rear wheel drive vehicle is running, and the power amount detecting means detects When the power amount of the motor power storage unit is less than a predetermined power amount, based on the detected power amount of the motor power storage unit and the regenerative power amount estimated by the regenerative power amount estimation unit, Determining means for determining whether to perform the step-up conversion by the step-up converter, and when the execution of the step-up conversion is determined by the determining means, Charge control means for causing the boost converter to perform the boost conversion of electric power to charge the boosted electric power to the motor power storage means. apparatus. 4. The step-up conversion by the step-up converter when the estimated power amount obtained by adding the estimated regenerative power amount to the power amount of the motor power storage unit is less than a second predetermined power amount. And when the predicted electric energy is equal to or greater than the second predetermined electric energy, the electric motor is further determined to execute power regeneration, and when the execution of the power regeneration is determined by the determination unit. 4. The front-rear wheel drive vehicle according to claim 3, further comprising: a regenerative charge control unit configured to cause the electric motor to perform the power regeneration, thereby charging the regenerative power to the motor power storage unit. Charge control device. 5. A front and rear wheel drive vehicle in which one of front and rear drive wheels is driven by an engine, the other is driven by an electric motor, and the other drive wheel and the electric motor are connected and disconnected by a clutch. A charge control device for a front-rear wheel drive vehicle that controls a charging operation for storing electric power for driving the electric motor, including power regeneration by the electric motor during travel of the front-rear wheel drive vehicle, Clutch state detection means for detecting a connection / disconnection state; motor drive state detection means for detecting whether the electric motor is driving the other drive wheel; power storage means for storing power; the electric motor A power storage means for storing power of a higher voltage than the power storage means for driving the power storage means, and a power amount detection means for detecting a power amount stored in the motor power storage means. Means, a boost converter for boosting and converting the power supplied from the power storage means to charge the motor power storage means, and a clutch connection state detected by the clutch state detection means, and the motor drive state detection means When the electric motor is detected as being driven, and when the power amount of the motor power storage unit detected by the power amount detection unit is less than a predetermined power amount, the boost converter
A charge control device for a front and rear wheel drive vehicle, comprising: charge control means for charging the motor power storage means with the boosted power by executing the boost conversion of power.