JP2012116411A - Battery charging and discharging controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a battery charging and discharging controller of a hybrid electric vehicle, which does not need suppression of charging and discharging current of a battery, due to a temperature rise of a battery, when traveling uphill.SOLUTION: The battery charging and discharging controller is installed in a hybrid electric vehicle equipped with: an engine 1 and a motor generator 4 outputting traveling torques; and a battery 40 chargeable with a power generated by the motor generator 4. The battery charging and discharging controller includes: a means 60 for acquiring a road condition ahead of a vehicle; a means 30a for determining whether there is an uphill road ahead of the vehicle, based on the acquired road condition ahead of the vehicle; and a controlling means 30d for restricting the charging and discharging of the battery 40 when the battery temperature becomes higher than that close to the upper limit temperature of the battery 40 as long as the means 30a does not determine there is an uphill road, and also for restricting the charging and discharging of the battery 40 when the temperature of the battery 40 becomes higher than a second predetermined temperature lower than a first one until the vehicle enters the uphill road when the means 30a determines there is an uphill road.

Description

  The present invention relates to a battery charge / discharge control device used in a hybrid electric vehicle.

  2. Description of the Related Art In recent years, hybrid electric vehicles equipped with an internal combustion engine (hereinafter also referred to as an engine) and a motor generator (hereinafter also referred to as an electric motor or simply as a motor) have been put into practical use as travel driving sources of the vehicle. This hybrid electric vehicle is equipped with a battery in order to supply power when the electric motor is powered, or to perform charging (energy recovery) using generated power during regenerative braking of the motor. In particular, the charging of the battery with the regenerative electric power of the motor contributes to the improvement of fuel consumption.

  For such a battery, a secondary battery such as a lithium ion battery is used. However, many secondary batteries such as a lithium ion battery generate heat when discharged with a large current. On the other hand, an endothermic reaction occurs when charged, but in the case of a battery mounted on an automobile, it is usually configured as a battery group (battery pack) in which a large number of single cells are connected in series. There is a possibility that the metal part for performing other series connection generates heat. When a large charge / discharge current is repeatedly applied, the temperature of each unit cell constituting the battery group is continuously increased.

Such secondary batteries are accelerated not only when excessively discharged or excessively charged, but also when used continuously at high temperatures.
For this reason, such a secondary battery is controlled not only to maintain its state of charge (SOC) within a predetermined range, but also to prevent the temperature state from becoming excessively high. Need to be controlled.

  In this regard, Patent Document 1 estimates a heat generation amount after a predetermined time elapses of each single cell constituting the battery group from a charge / discharge current flowing through the battery group (battery pack), and the estimated heat generation amount is determined in advance. If the set value is exceeded, the charge / discharge current flowing through the battery group is suppressed to suppress the temperature rise of the unit cell in use, resulting in heat generation. A technique for preventing the deterioration of the unit cell has been proposed.

JP 2009-81958 A

  By the way, in the case of a hybrid electric vehicle, a large driving torque can be obtained by operating the engine and powering the electric motor. When traveling on an uphill road, a large vehicle driving torque is required. By driving the vehicle by using both the engine and the electric motor in this way, a large vehicle driving torque can be obtained and the vehicle speed can be reduced. The vehicle can travel without causing a drop.

Also, from a different perspective, the engine driving torque burden can be reduced by the driving torque of the electric motor, and the engine operating state can be brought close to the best fuel efficiency point. Thereby, the fuel consumption of the engine can be saved.
In particular, in the case of large commercial vehicles such as trucks and buses where the vehicle weight greatly increases depending on the load and passengers, the fact that a large vehicle driving torque can be obtained and that the fuel consumption of the engine can be reduced is advantageous from the viewpoint of commercial operation. large.

  However, when traveling on an uphill road, as described above, there may be a case where the charge / discharge current of the battery must be suppressed or regulated in order to suppress the rise in the battery temperature because the battery temperature is high. In this case, there are conceivable situations where the output torque due to the power running operation of the electric motor should be suppressed, or a situation where the motor torque cannot be generated itself, leading to a decrease in vehicle speed or fuel due to an increase in the engine driving torque burden. It will increase consumption. The conventional technology such as Patent Document 1 does not take measures against such a problem.

  The present invention has been devised in view of such problems, and it is possible to eliminate battery charge / discharge current suppression caused by a rise in battery temperature when traveling on an uphill road. It aims at providing a discharge control device.

  In order to achieve the above object, a battery charge / discharge control device according to the present invention includes an engine that can output a traveling torque of a vehicle, a power generation and braking that can output the traveling torque of the vehicle and that drives the engine. A battery temperature detecting means for detecting the temperature of the battery, which is provided in a hybrid electric vehicle comprising a motor generator capable of generating power by energy regeneration at the time, and a battery that can be charged by power generated by the motor generator; Determining whether there is an uphill road ahead of the vehicle based on the road condition acquisition means for acquiring the road condition in front of the vehicle and the road condition in front of the vehicle acquired by the road condition acquisition means Uphill road determining means and the uphill road determining means determine that there is an uphill road, the temperature of the battery is the upper limit temperature of the battery or above When charging and discharging of the battery is limited when the temperature becomes higher than a first predetermined temperature that is a temperature near the temperature, and the uphill road determination means determines that there is an uphill road, until the vehicle enters the uphill road Comprises a control means for restricting charging / discharging of the battery when the temperature of the battery becomes higher than a second predetermined temperature which is lower than the first predetermined temperature by a predetermined temperature difference. It is a feature.

  Battery charge amount detection means for detecting the charge amount of the battery is further provided, and the control means detects when the charge amount detected by the battery charge amount detection means is less than a predetermined charge amount (value on the SOC lower limit side). Restricts the discharging of the battery and limits the charging of the battery when the temperature of the battery becomes higher than the first predetermined temperature, and when the charging amount is equal to or higher than the predetermined charging amount, Until the vehicle enters the uphill road, it is preferable to limit charging / discharging of the battery when the temperature of the battery becomes higher than the second predetermined temperature.

  Further comprising vehicle speed detection means for detecting the vehicle speed of the vehicle, the control means based on the vehicle speed detected by the vehicle speed detection means and the road condition in front of the road acquired by the road condition acquisition means, It is preferable that the amount of heat generated in the motor generator when traveling on the uphill road is calculated using the output torque of the motor generator, and the predetermined temperature difference is set based on the amount of heat generated.

  According to the battery charge / discharge control device of the present invention, when there is an uphill road ahead of the vehicle, the battery temperature is a predetermined temperature higher than the first predetermined temperature which is the upper limit temperature of the battery or a temperature in the vicinity of the upper limit temperature. When the low second predetermined temperature is reached, charging / discharging of the battery is restricted until the vehicle enters the uphill road, so that when the vehicle enters the uphill road, the battery temperature becomes lower than the upper limit temperature. Since the charging / discharging limitation of the battery due to the battery temperature is not performed, it is possible to travel on the uphill road using the driving torque generated by the motor generator using the electric power of the battery.

Therefore, by driving the vehicle using both the engine and the motor generator, a large vehicle driving torque can be obtained, and a decrease in the vehicle speed on the uphill road can be prevented.
Further, the driving torque burden of the engine can be reduced by the amount of driving torque generated by the motor generator, and the engine operating state can be brought close to the best fuel consumption point. Thereby, the fuel consumption of the engine can be saved.

In particular, in the case of large commercial vehicles such as trucks and buses where the vehicle weight greatly increases depending on the load and passengers, the fact that a large vehicle driving torque can be obtained and that the fuel consumption of the engine can be reduced is advantageous from the viewpoint of commercial operation. large.
In addition, when the battery charge is less than the predetermined charge, recovery of the battery charge is more urgent than allowing the battery to discharge when traveling on an uphill road. Since discharging is restricted and charging of the battery is restricted when the temperature of the battery becomes higher than the first predetermined temperature, charging of the battery is not restricted until the temperature of the battery rises to the first predetermined temperature. The amount of charge can be recovered while managing the temperature of the battery.

  Based on the vehicle speed and the road conditions ahead of the vehicle, the amount of heat generated in the motor generator when traveling on the uphill road using the output torque of the motor generator is obtained, and the first predetermined amount is determined based on the amount of heat generated. If a temperature difference (predetermined temperature difference) between the temperature and the second predetermined temperature is set, the battery temperature is managed not to rise excessively even when the vehicle is driven using a motor generator on the uphill road. It becomes possible to do.

1 is a configuration diagram of a power system of a hybrid electric vehicle to which a battery charge / discharge control device according to an embodiment of the present invention is applied. It is a time chart explaining control by the battery charging / discharging control apparatus concerning one Embodiment of this invention. It is a flowchart explaining the control by the battery charging / discharging control apparatus concerning one Embodiment of this invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a configuration diagram of a power system of a hybrid electric vehicle according to the present embodiment, FIG. 2 is a time chart for explaining control by the battery charge / discharge control device, and FIG. 3 is a flowchart for explaining control by the battery charge / discharge control device. It is. This will be described with reference to these drawings.

[Configuration of power system]
First, a configuration of a power system of a hybrid electric vehicle to which the battery charge / discharge control device according to the present embodiment is applied will be described.
The hybrid electric vehicle according to the present embodiment is a commercial vehicle such as a truck or a bus, and is equipped with a diesel engine.
As shown in FIG. 1, an engine (internal combustion engine) 1, a clutch 2, a motor (motor generator) 3, and a transmission (transmission) 4 are provided as a drive system at the front portion of the vehicle.
The clutch 2 is interposed between the engine 1 and the motor 3. If the clutch 2 is disconnected, the engine 1 is disconnected from the drive system of the vehicle and no power is transmitted. If the clutch 2 is connected, the engine 1 is disconnected. Is added to the drive system of the vehicle to transmit power.

  The motor 3 is always connected to the transmission 4 immediately downstream thereof, and its operation is controlled by an inverter 41. The inverter 41 supplies power to the motor 3 from a battery (for example, a battery group in which a plurality of chargeable / dischargeable secondary cells (cells) such as lithium ion batteries are connected in series) during powering. The motor 3 functions as an electric motor that generates torque, and at the time of regenerative braking, the motor 3 functions as a generator that generates electric power (regenerative power generation) using the kinetic energy of the vehicle, and the electric power generated by the regenerative power generation is used for charging the battery 40. Is done.

The input shaft of the transmission 4 is connected to the rotating shaft of the motor 3, and the output shaft of the transmission 4 is connected via a power transmission system including a propeller shaft 5, a differential 6, a drive shaft 7, and the like. It is connected to drive wheels (here, left and right rear wheels) 8.
Therefore, during power running of the vehicle, the drive torque input to the input shaft of the transmission 4 is shifted at a gear ratio corresponding to the selected gear and output to the power transmission system. In this case, if the clutch 2 is connected, both the output torques of the engine 1 and the motor 3 transmitted through the clutch 2 are input to the transmission 4, and if the clutch 2 is disconnected, the output torque of only the motor 3 is obtained. Input to the transmission 4.

  At the time of regenerative braking, the rotational torque due to the kinetic energy of the vehicle is input from the drive wheels 8 through the power transmission systems 7, 6, 5 to the transmission 4, and the input rotation from the drive wheels 8 is applied to the gear stage of the transmission 4. The motor 3 that functions as a generator is driven to rotate by changing the gear ratio, and regenerative power generation can be performed together with braking of the vehicle. In this case, if the clutch 2 is disengaged, the kinetic energy of the vehicle is used only for driving the motor 3 as a generator, and energy can be recovered efficiently. If the clutch 2 is connected, the combined use of the regenerative brake and the engine brake by the control of the motor 3 by the inverter 41 or the operation of only the engine brake can be performed.

[Control system configuration]
Control or management of the engine 1, the clutch 2, the motor 3, the battery 40, and the inverter 41 is performed by electronic control using a computer.
An engine ECU 31 for controlling the engine 1, an inverter ECU 32 for controlling the inverter 41 for operating the operation of the motor 3, and a battery ECU 33 for managing the battery 40 are provided, respectively. A vehicle ECU 30 is provided to control the ECU 32, the battery ECU 33, and the clutch 2.

Each of the ECUs 30, 31, 32, and 33 is a computer including a CPU, a ROM, a RAM, an input / output circuit, and the like, and appropriate devices are attached or connected thereto.
The vehicle ECU 30 determines the vehicle running state (for example, vehicle speed), the driving or braking command state (for example, accelerator operation amount or brake operation amount) for the vehicle, the charge amount of the battery 40 (hereinafter, the charge amount value). The engine ECU 31, the inverter ECU 32, the battery ECU 33, and the clutch 2 are controlled based on the temperature state of the battery 40 and the like.

  The battery ECU 33 includes a battery current sensor 51 that detects a charge / discharge current of the battery 40, a battery voltage sensor 52 that detects a charge / discharge voltage of the battery 40, and a battery charge / discharge counter that detects the number of times of charge / discharge of the battery 40. 54, and the charge amount SOC of the battery 40 is calculated by the battery ECU 33 based on the current and voltage when the battery 40 is charged and discharged. Therefore, the battery ECU 33 corresponds to battery charge amount detection means.

  These sensors 51 and 52 and the counter 54 are connected to each cell of the battery 40, and may detect the current, voltage, and number of charge / discharge of each cell, or one sensor for several cells. May be connected to detect the current, voltage, temperature, and number of charge / discharge of these several cells, or connect one sensor to each of these cells or several cells. You may arrange | position each sensor combining suitably.

In addition, the inverter ECU 32 controls the inverter 41 to manage the power transfer of the motor 3 and the battery 40 connected to the inverter 41. For example, the power generated by the regenerative power generation of the motor 3 is applied to the battery 40.
When driving, the vehicle ECU 30 sets a driving torque necessary for the vehicle based on the accelerator operation amount, and sets which one of the engine 1 and the motor 3 is used, or both of them. When both the motor 3 and the motor 3 are used, the drive torque is distributed. The engine ECU 31 and the inverter ECU 32 control the operation of the engine 1 or the motor 3 so as to output the driving torque set by the vehicle ECU 30.

  For example, when the vehicle starts, the clutch 2 is basically disengaged and the driving torque of only the motor 3 is used, and during the subsequent driving, the engine 1 is started and the clutch 2 is connected, and the driving torque of the engine 1 is mainly used. In addition, the vehicle travels using the driving torque of the motor 3 as an auxiliary. However, when the amount of charge of the battery 40 is insufficient, or when the temperature of the battery 40 has risen to a predetermined temperature or more, the vehicle 1 travels using only the engine 1 without using the motor 3 when starting or traveling. To do.

Further, at the time of braking, basically, the clutch 2 is disengaged and the rotational energy of the drive wheels 8 is sent only to the motor 3 to perform regenerative power generation. The electric power generated by the regenerative power generation is normally used for charging the battery 40.
However, when the charge amount SOC of the battery 40 has reached the upper limit (full charge) or near the upper limit (substantially full charge), or when the temperature of the battery 40 has risen above a predetermined temperature, regenerative power generation Cannot be used for charging the battery 40.

That is, when the amount of charge of the battery 40 becomes excessively high, deterioration is promoted with heat generation. Moreover, even if the charge amount is excessively reduced, the deterioration is caused. Therefore, the vehicle ECU 30 also manages the charge amount of the battery 40.
Furthermore, when the temperature of the battery 40 becomes excessively high, deterioration is promoted. Therefore, the vehicle ECU 30 also manages the temperature of the battery 40.

In particular, this temperature management is particularly important for heavy commercial vehicles.
In other words, as described above, this hybrid electric vehicle is a heavy commercial vehicle, and it is important to secure a transportable weight and a loading space, and further suppress an increase in vehicle cost. It is also important. The first purpose of applying the hybrid vehicle is to improve the fuel consumption. Therefore, in consideration of the balance with the conditions necessary for such a commercial vehicle, the battery 40 has a battery capacity (charge capacity, heat capacity) relative to the size of the vehicle as compared with that of a passenger car of a normal hybrid electric vehicle. A relatively small one is mounted.

  Furthermore, in the case of commercial vehicles, there are many large vehicles compared to passenger cars from the viewpoint of securing the loaded weight and efficient transportation. For this reason, high-torque powering operation and regenerative braking of the motor 3 are often performed. That is, there are many cases where the battery 40 having a limited capacity is charged with a large current by discharging the motor for powering operation or charging the motor by regenerative braking. Since the battery 40 has a small capacity and a small heat capacity, if the battery 40 performs a high-torque power running operation or regenerative braking of the motor 3 that generates heat of a large amount of heat, the individual cells of the battery 40 are in contact with each other. The temperature rise of the battery 40 due to the heat generation of the metal part also becomes significant.

Since the deterioration of the battery 40 is accelerated when the battery 40 is in a high temperature state, the temperature management of the battery 40 so that the vehicle ECU 30 does not excessively increase the temperature of the battery 40 is extremely important.
For temperature control of the battery 40, the battery 40, the battery temperature sensor 53 for detecting the temperature of the battery 40 is equipped, the battery temperature sensor 53, the detected battery temperature T _B information is input to the vehicle ECU30 So that they are connected.

Further, in order to manage the charge amount of the battery 40, the charge amount SOC of the battery 40 calculated from the battery ECU 33 connected to the vehicle ECU 30 is input.
Further, in the case of this apparatus, not only the charge amount and temperature of the battery 40 are managed, but also when there is an uphill road ahead of the vehicle, the power of the battery 40 is used as much as possible for traveling on this uphill road. Thus, the vehicle ECU 30 performs specific battery management so that the vehicle 2 can travel using the output torque of the motor 2 that is generated.

  In order to manage the battery 40 as described above, the vehicle ECU 30 includes an uphill road determination unit 30a, a calorific value estimation unit 30b, a temperature setting unit 30c, and a charge / discharge restriction unit 30d, all of which function by computer software. It is provided as an element. These will be described below.

[Control of battery management]
The uphill road determination unit 30a determines whether there is an uphill road ahead of the host vehicle based on the road state information ahead of the vehicle input from the road state acquisition unit 60 to the vehicle ECU 30. In the present embodiment, a navigation system mounted on a vehicle is used for the road condition acquisition unit 60.
That is, this in-vehicle navigation system includes a map database (storage device) in which map data in which altitude information is added to position information of each point is registered, and a current position determination function for determining the current position of the host vehicle, By setting the planned travel route of the host vehicle, the road ahead of the host vehicle can be identified from the map data and the current position of the host vehicle determined. The distance and altitude of each point from the current position of the host vehicle can be acquired and output as information, and functions as road condition acquisition means 60.

  The ascending road determination means 30a detects the altitude of each point on the road within a predetermined distance (distance) from the current position of the host vehicle, and the altitude is continuous over a predetermined distance (distance). It is determined that the part that rises is an uphill road. If there is an uphill road within the range of the set distance (road) in front of the host vehicle, it is determined that “the uphill road is in front of the host vehicle”, and there is no uphill road within the set distance range in front of the host vehicle. For example, it is determined that “there is no uphill road ahead of the host vehicle”.

The calorific value estimating means 30b uses the output torque of the motor 2 generated by discharging the battery 40 on the uphill road when the uphill road judging means 30a determines that "there is an uphill road ahead of the host vehicle". Then, the heat generation amount Q _B of the battery 40 when traveling is estimated. Here, from the calorific value Q _BIN1 according to the discharge of each cell of the battery 40 and the calorific value Q _BIN2 due to energization of the metal part between the cells, the calorific value Q _B of the battery 40 is _expressed by the following equation (1). Is estimated.
Q _B = Q _BIN1 + Q _BIN2 (1)

The heat generation Q _BIN1 corresponding to the cell discharge is a value ∫R ₁ I obtained by time-integrating a multiplication value RI ² of the internal resistance R ₁ (known value) of each cell and the square I ² of the instantaneous current value I. is proportional to ² dt, the constant value I _US Shun uphill travel time a current value I during uphill road travel can be calculated by the following equation (2) as t1. Further, the heat generation Q _BIN2 caused by energization of the metal part between the cells is a value obtained by time-integrating the _product value R ₂ I ² of the resistance R ₂ (known value) of the metal part and the square I ² of the instantaneous current value I. Since it is proportional to R ₂ I ² t, it can be calculated by the following equation (3), where the current value I during traveling on the uphill road is a constant value I _{US and the} traveling time on the uphill road is t1. The uphill traveling time t1 can be calculated from the length L of the uphill road and the assumed vehicle speed V traveling on the uphill road by the following equation (4).
Q _BIN1 = C1 · R ₁ I ² t1 C1: proportional multiplier (2)
Q _BIN2 = C2 · R ₂ I ² t1 C2: proportional multiplier (3)
t1 = L / V (4)

The temperature setting means 30c sets the second set temperature T _B2 by subtracting a predetermined temperature difference ΔT _B from the first set temperature T _B1 . The first set temperature T _B1 is administrative of Raising the temperature T _B of the battery 40 more to the battery 40 to deterioration of the battery 40 is estimated to be facilitated more than acceptable limits upper limit temperature or the upper limit temperature The temperature is near (lower than the upper limit temperature by a margin).

The predetermined temperature difference ΔT _B is a temperature increase in which the temperature of the battery 40 increases due to the heat generated by the battery 40 when the vehicle travels on the uphill using the output torque of the motor 2, and this temperature increase Since the minute (predetermined temperature difference) ΔT _B is proportional to the calorific value Q _B estimated by the calorific value estimation means 30b, it can be calculated by the following equation (5). Therefore, the second set temperature _TB2 can be calculated by the following equation (6).
ΔT _B = C · Q _B C: Proportional multiplier ... (5)
T _B2 = T _B1 −ΔT _B (6)

When the charge amount SOC calculated (detected) by the battery ECU (charge amount detection means) 33 is less than the predetermined charge amount SOC _min , the charge / discharge restriction unit 30d does not restrict charging but restricts discharging. The predetermined charge amount SOC _min is a value set as an allowable lower limit value for managing the charge amount SOC because the battery 40 is deteriorated when the charge amount SOC is excessively decreased. In this case, the restriction of charging and discharging here completely prohibits charging and discharging.

Discharge restriction means 30d is even state of charge SOC calculated by the battery ECU (charge amount detection means) 33 is more than a predetermined charge amount _{SOC min,} the temperature _{T B} of the battery 40 is higher than the determination reference temperature _{T BS} If this happens, it limits both charging and discharging of the battery. However, usually, when the determination reference temperature T _BS, the first is the predetermined temperature T _B1 which is the upper limit temperature or the upper limit temperature near the temperature of the battery 40, uphill determining means 30a is determined that uphill, Until the vehicle enters the uphill road, the determination reference temperature T _BS is determined as the second predetermined temperature T _{B2 that} is lower than the first predetermined temperature T _B1 by the predetermined temperature difference ΔT _B as described above, and the battery 40 Limit charging and discharging.

(Action, effect)
Since the battery charge / discharge control device according to the embodiment of the present invention is configured as described above, for example, as shown in FIGS. 2 and 3, the vehicle ECU 30 controls the charge / discharge of the battery 40.
That is, as shown in FIG. 3, first, information on road conditions ahead of the host vehicle from the road condition acquisition means 60, battery charge SOC from the battery ECU (battery charge detection means) 33, and battery temperature sensor. It obtains the battery temperature _{T B} from 53 (step S10).

Then, it is determined whether or not the battery charge amount SOC is less than the predetermined charge amount SOC _min (step S20). If the battery charge amount SOC is less than the predetermined charge amount SOC _min , discharging is limited (step S80). Therefore, even if the battery 40 is not charged, the battery charge amount SOC is maintained in the vicinity of the predetermined charge amount SOC _min .
Meanwhile, the charge is limited according to the battery temperature T _B. That is, the determination reference temperature T _BS of the set to the first set temperature T _B1 is the temperature of the vicinity of the upper limit temperature or the upper limit temperature administrative of the battery 40 (step S90), the temperature T _B is the determination reference temperature T of the battery 40 _It is determined whether or not the temperature is equal to or higher than _BS (step S100). If the temperature T _{B of the} battery 40 rises above the determination reference temperature T _BS (= first set temperature T _B1 ), charging is also limited.

Thus, as long as the temperature T _B of the battery 40 does not rise to the first set temperature T _B1 above, charging because it is not limited, and to charge the battery 40 by regenerative braking, it is possible to restore the battery charge SOC .
On the other hand, if the battery charge amount SOC is not less than the predetermined charge amount SOC _min , it is determined whether or not the host vehicle is traveling on an uphill road and there is an uphill road ahead of the host vehicle (step S30). If the vehicle is uphill path and the vehicle ahead rather than during uphill traveling, and sets the determination reference temperature T _BS in the second set temperature T _B2 (step S40), the temperature T _B of the battery 40 is the it is determined whether the determination reference temperature _{T BS} or more (step S60), when the temperature _{T B} of the battery 40 is the determination reference temperature _{T BS} (= second set temperature _{T B2)} above increases, limiting the charging and discharging (step S70).

The second set temperature _TB2 is the first set temperature that is the upper limit temperature of the battery by the amount of the temperature rise when the temperature of the battery 40 rises due to the heat generated by the battery 40 when the vehicle travels on the uphill using the output torque of the motor 2. since lower temperature than T _B1, the vehicle is then (at this stage, the determination reference temperature T _B is is is set to the first set temperature T _B1) and later enters the uphill road, the temperature of the battery 40 battery limit It is possible to travel on the uphill road using the output torque of the motor 2 while keeping it within the first set temperature _TB1, which is the temperature.

Further, in step S30, whether being uphill road, or, if there is no uphill in front of the vehicle, since the determination reference temperature T _B is set to the first set temperature T _B1 (step S40), As long as the temperature T _B of the battery 40 does not rise above the first set temperature T _B1 , charging / discharging is not limited, and the battery 40 can be charged and discharged without hindrance.
For example, FIG. 2 shows that in a situation where the battery charge amount SOC is ensured to be equal to or greater than the predetermined charge amount SOC _min and the uphill road us is ahead of the vehicle C, the vehicle C goes down the downhill road ds before the uphill road us. In this case, the temperature of the battery 40 is increased to the second set temperature _TB2 .

If the prior art, since the temperature of the battery 40 to charge or discharge the battery unless rise to the first set temperature T _B1 is not regulated, the temperature of the battery 40 have down the vehicle C downhill ds second set temperature T _{Even if} it rises to _B2, charging by regenerative power generation is continued. However, as the charging continues, the temperature of the battery 40 continues to rise. When the vehicle C enters the entrance us1 of the uphill road us and travels on the uphill road us using the output torque of the motor 2. in the middle, and the temperature rise of the battery 40 to the first set temperature T _B1, the charge and discharge of the battery is restricted. For this reason, the output torque of the motor 2 cannot be used, and the vehicle driving torque is reduced by that amount, which may cause a decrease in the vehicle speed on the uphill road us. In addition, the driving torque burden of the engine increases by the amount of reduction of the driving torque by the motor generator, and the fuel consumption efficiency increases.

On the other hand, in the apparatus of the present invention, charging by regenerative power generation is stopped when the vehicle C is going down the downhill road ds and the temperature of the battery 40 has risen to the second set temperature _TB2 . Therefore, energy cannot be recovered as electric power as much as the battery 40 cannot be charged by regenerative power generation (however, the electric power generated by regenerative power generation can be used for other than charging the battery 40), but the vehicle C then climbs up the slope. after entering the road entrance us1, the temperature of the battery 40 can be partitioned traveling first set temperature T _B1 using the output torque of the motor 2 while maintaining within uphill us is a battery maximum temperature.

Therefore, by using both the engine 1 and the motor 2 to drive the vehicle, a large vehicle driving torque can be obtained, and a decrease in the vehicle speed on the uphill road can be prevented.
Further, the driving torque burden of the engine 1 can be reduced by the amount that can secure the driving torque by the motor 2, and the fuel consumption of the engine can be saved.
In particular, in the case of large commercial vehicles such as trucks and buses where the vehicle weight greatly increases depending on the load and passengers, the fact that a large vehicle driving torque can be obtained and that the fuel consumption of the engine can be reduced is advantageous from the viewpoint of commercial operation. large.

[Others]
Although one embodiment of the present invention has been described above, the present invention is not limited to such an embodiment, and a part of the embodiment may be changed or the implementation may be performed without departing from the spirit of the present invention. It can be implemented by applying only a part of the form.
For example, in the above embodiment, charging and discharging restrictions are completely prohibited from being charged and discharged, but charging and discharging restrictions are set to a level lower than a preset level (current value) of charging and discharging. It may be possible to keep it at a minimum.

In the above embodiment, an example of application to a heavy commercial vehicle has been described. However, the object of the present invention is not limited to such an automobile, and can be applied to a vehicle other than an automobile (railway vehicle). is there.
Further, the engine mounted on the vehicle is not limited to the diesel engine.

1 Engine 2 Clutch 3 Motor (motor generator)
4 Transmission 5 Propeller Shaft 6 Differential 7 Drive Shaft 8 Drive Wheel 30 Vehicle ECU
30a Uphill road judging means 30b Heat generation amount estimating means 30c Temperature setting means 30d Charge / discharge limiting means 31 Engine ECU
32 Inverter ECU
33 battery ECU (battery charge detection means)
DESCRIPTION OF SYMBOLS 40 Battery 41 Inverter 51 Battery current sensor 52 Battery voltage sensor 53 Battery temperature sensor 54 Battery charge / discharge counter 60 Navigation system (road condition acquisition means)

Claims (3)

An engine capable of outputting a running torque of the vehicle, a motor generator capable of outputting the running torque of the vehicle and capable of generating power by driving the engine and generating power by energy regeneration during braking, and the motor generator Equipped on a hybrid electric vehicle equipped with a battery that can be recharged by generated power,
Battery temperature detecting means for detecting the temperature of the battery;
Road condition acquisition means for acquiring the road condition ahead of the vehicle;
Uphill road determination means for determining whether there is an uphill road ahead of the vehicle based on the road situation ahead of the vehicle acquired by the road condition acquisition means;
Charging / discharging of the battery when the temperature of the battery becomes higher than a first predetermined temperature that is the upper limit temperature of the battery or a temperature in the vicinity of the upper limit temperature, unless the climbing path determination means determines that there is an uphill path When the uphill road determination means determines that there is an uphill road, the battery temperature is lower by a predetermined temperature difference than the first predetermined temperature until the vehicle enters the uphill road. A battery charge / discharge control device comprising: control means for restricting charge / discharge of the battery when the temperature becomes higher than a predetermined temperature. Battery charge amount detecting means for detecting the charge amount of the battery,
When the charge amount detected by the battery charge amount detection means is less than a predetermined charge amount, the control means restricts discharging of the battery and charges the battery at a temperature of the first battery. The battery is limited to a temperature higher than a predetermined temperature. When the charge amount is equal to or higher than the predetermined charge amount, the battery temperature is higher than the second predetermined temperature until the vehicle enters the uphill road. 2. The battery charge / discharge control device according to claim 1, wherein charge / discharge of the battery is restricted when the value becomes higher. Vehicle speed detecting means for detecting the vehicle speed of the vehicle,
The control means uses the output torque of the motor generator based on the vehicle speed detected by the vehicle speed detection means and the road condition ahead of the road acquired by the road condition acquisition means. The battery charge / discharge control device according to claim 1, wherein the heat generation amount generated in the motor generator when traveling is obtained, and the predetermined temperature difference is set based on the heat generation amount.

Images