JP2014222989A - Regeneration control apparatus for electric automobile - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a regeneration control apparatus for an electric automobile, the apparatus capable of charging a battery by efficiently converting kinetic or potential energy of a vehicle into power while preventing deterioration and breakdown of the battery due to excessive charging during a downhill travel and the like, thus enabling improvement in energy efficiency of the entire vehicle.SOLUTION: A regeneration control apparatus performs: obtaining information of a downhill road existing ahead of a vehicle (S2); predicting respective calorific values H(n) of a battery at plural determination periods Tlim(n) on the basis of the obtained information of the downhill road (S10); selecting a minimum value of a current Iopt corresponding to an individual upper limit value Hlim(n) that has been determined to exceed (S20, 22) in a case where any of the calorific values H(n) exceeds respective upper limit values Hlim(n) (No for S12); and controlling a motor output on the basis of a target output Pdem calculated from the selected current Iopt (S24).

Description

  The present invention relates to a regenerative control device for an electric vehicle, and more particularly to a regenerative control device that charges a battery with electric power generated by regenerative control of a motor during traveling on a downhill road.

In order to improve the efficiency of an engine vehicle equipped with an engine as a conventional driving power source, a hybrid electric vehicle equipped with a motor as a driving power source in addition to the engine, or an electric vehicle equipped with a motor instead of the engine (Hereinafter collectively referred to as an electric vehicle).
In such an electric vehicle, since the motor can be operated as a generator by controlling the regeneration of the motor, for example, when traveling on a downhill road, the motor generates power by reverse driving from the drive wheel side, and the generated power is transferred to the battery. Charging. As a result, the kinetic energy or potential energy of the vehicle can be recovered as electric power, and the electric power discharged from the battery is used during subsequent driving by the motor.

By the way, a lithium secondary battery or the like is mounted as a battery in this type of electric vehicle, but there is a thermal restriction on the current during charging and discharging. That is, the charging / discharging current exceeding the limit is consumed for the temperature rise of the battery, and as a result, the battery is overheated and causes deterioration or breakage. Therefore, for example, in the technique disclosed in Patent Document 1, the heat generation amount H is calculated from the following equation (1) based on the current I during charging / discharging of the battery and the determination time t, and the heat generation amount H is set to a preset upper limit allowable value. Measures are taken to limit the charge / discharge current when the value is exceeded.
H = I ² t …… (1)

JP 2009-81958 A

  The battery protection measures described in Patent Document 1 are also implemented when the electric vehicle is regenerated as described above. However, for example, on a steep and long downhill road, charging of the battery by regenerative control of the motor is performed with a large current for a long time. Therefore, the heat generation amount H calculated from the above equation (1) suddenly increases and exceeds the upper limit allowable value of the battery at an early stage, and the regeneration control of the motor is stopped or the regeneration control is limited by suppressing the charging current. It will be.

Thus, for example, even if the road is steep and long enough to increase the SOC (State Of Charge) of the battery to the upper limit of the control range (hereinafter referred to as full battery charge), the battery is fully charged at that time. It cannot be charged. This situation means that the kinetic energy or potential energy of the vehicle that should be obtained by the downhill road cannot be effectively used as electric power, and a drastic countermeasure has been demanded from the past.
The present invention has been made to solve such problems, and the object of the present invention is to prevent the battery from being deteriorated or damaged due to excessive charging during traveling on a downhill road or the like. It is an object of the present invention to provide a regenerative control device for an electric vehicle that can efficiently convert the kinetic energy or potential energy into electric power and charge the battery, thereby improving the energy efficiency of the entire vehicle.

  In order to achieve the above object, the present invention travels by transmitting the driving force of a motor equipped as a driving power source to driving wheels, and reversely drives from the driving wheels while traveling downhill. In an electric vehicle that regeneratively controls and recharges the battery with regenerative power, downhill road information acquisition means for acquiring downhill road information existing in front of the vehicle, and downhill road information acquired by the downhill road information acquisition means Based on this, the heat generation amount predicting means for predicting the heat generation amount generated due to the charging of the battery at a plurality of preset determination times when traveling on a downhill road while regeneratively controlling the motor at the maximum possible output And a first heat generation amount for determining whether or not the predicted heat generation amount for each determination time predicted by the heat generation amount prediction means exceeds an upper limit allowable value set in advance corresponding to each determination time. The battery charging current corresponding to each upper limit allowable value determined to exceed when any of the predicted heat generation amounts exceeds the corresponding upper limit allowable value. When calculating the minimum value, selecting the minimum value, calculating the motor output based on the minimum charging current and setting it as the target output, and when the vehicle reaches the downhill road and travels on the downhill road, A motor that controls the output of the motor based on the target output set by the target output setting means when any one of the predicted heat generation amounts exceeds the corresponding upper limit allowable value by the first heat generation amount determination means Output control means.

  Based on the information of the downhill road existing in front of the vehicle, the amount of heat generated by the battery when traveling on the downhill road while regeneratively controlling the motor with the maximum possible output is predicted for each of a plurality of determination times. If any of these predicted heat generation values exceeds the corresponding upper limit allowable value, the charging current of the battery corresponding to the upper limit allowable value determined to exceed is calculated, and calculated from the charging current selected as the minimum value. The motor output is controlled based on the target output. For this reason, the charging current of the battery is not limited based on the amount of heat generation, and a substantially constant regeneration torque is maintained during the regeneration control of the motor, so that the amount of power generation that can be secured as a whole can be increased.

  As another aspect, when the target output setting unit determines that all the predicted heat generation amounts do not exceed the corresponding upper limit allowable value by the first heat generation amount determination unit, charging of the battery corresponding to each predicted heat generation amount Preferably, each current is calculated to select the maximum value, and the motor output is calculated based on the maximum charging current and set as the target output.

  If all predicted heat generation amounts do not exceed the corresponding upper limit allowable value, the charging current corresponding to each heat generation amount is calculated, and the motor output is based on the target output calculated from the charging current selected as the maximum value. Be controlled. In this case, since the heat generation amount is predicted not to exceed the upper limit allowable value under any of the limiting conditions, the largest possible power generation amount can be ensured by controlling the motor based on the maximum charging current.

  As another aspect, when the target output setting means sets the motor output calculated from the minimum charging current as any predicted heat generation amount exceeding the corresponding upper limit allowable value as the target output, The target output is corrected to the increase side in the first half of the judgment time corresponding to the upper limit allowable value selected for the charging current, the target output is corrected to the decrease side in the second half of the judgment time, and the correction on the increase side and the decrease side is the judgment time. It is preferable that a target output correction unit that repeats every time is provided, and the motor output control unit controls the output of the motor based on the target output corrected by the target output correction unit.

  When traveling on the downhill road is completed in the middle of the determination time, the motor output is increased in the first half compared to the second half of the determination time, so that the SOC of the battery can be further increased at the end of the downhill road. Therefore, it is possible to secure a larger amount of power generation while avoiding the current limitation based on the heat generation amount limitation condition.

  As another aspect, the battery includes a second heat generation amount determination unit that determines a heat generation amount of the battery when the vehicle reaches the downhill road, and the target output correction unit is determined by the second heat generation amount determination unit. When the heat generation amount exceeds the preset heat generation amount determination value, the target output is corrected so as to change at a substantially constant rate of change from the predetermined value on the increase side to the predetermined value on the decrease side within the determination time. When the calorific value determined by the calorific value determination means is equal to or less than the calorific value determination value, the target output is corrected to an approximately constant value on the increase side in the first half of the determination time and is set to an approximately constant value on the decrease side in the latter half of the determination time. It is preferable to correct.

  When the amount of heat generated when reaching the downhill road exceeds the heat generation amount determination value, the target output is corrected so as to change at a substantially constant change rate from a predetermined value on the increase side to a predetermined value on the decrease side. Since the amount of generated heat is difficult to increase, the amount of power generation can be increased while avoiding the limitation of the charging current. When the amount of heat generated when reaching the downhill road is equal to or less than the heat generation amount determination value, the target output is corrected to a substantially constant value on the increase side in the first half of the determination time, and is decreased to a substantially constant value on the decrease side in the second half of the determination time. It is corrected. Since the calorific value is still low, even if the calorific value increases, the upper limit allowable value is not exceeded, and a larger amount of power generation can be secured.

  As another aspect, the downhill road information acquisition unit acquires road surface information immediately after the downhill road along with the downhill road information, and based on the road surface information immediately after the downhill road acquired by the downhill road information acquisition unit. The motor output prediction means for predicting the motor output required for traveling immediately after the slope is provided, and the target output correction means increases or decreases the target output as the motor output predicted by the motor output prediction means increases. It is preferable to reduce the correction amount.

  As the predicted motor output is larger, the correction amount of the target output is reduced, so that the amount of heat generated at the end of traveling on the downhill road is suppressed. Therefore, even if the heat generation amount of the battery is increased by performing power running control on the uphill road immediately after the downhill road, a situation where the heat generation amount exceeds the upper limit allowable value can be avoided. For this reason, the interruption of the power running control due to the limitation of the discharge current can be prevented and the drivability of the vehicle can be improved.

  According to the present invention, the battery can be charged by efficiently converting the kinetic energy or potential energy of the vehicle into electric power after preventing deterioration or breakage of the battery due to excessive charging during traveling on a downhill road, Thus, the energy efficiency of the entire vehicle can be improved.

It is a whole lineblock diagram showing a hybrid truck carrying a regeneration control device of an embodiment. It is a flowchart which shows the motor regeneration control routine which vehicle ECU of 1st Embodiment performs. It is a time chart which shows the execution situation of motor regeneration control in a 1st embodiment. It is a time chart which shows the execution situation of motor regeneration control in a 2nd embodiment. It is a time chart which shows the fluctuation state of the motor output in regeneration control in 2nd Embodiment. It is a time chart which shows the fluctuation state of the motor output in the regeneration control in another example of 2nd Embodiment.

[First Embodiment]
A first embodiment in which the present invention is embodied in a regenerative control device for a hybrid truck will be described below.
FIG. 1 is an overall configuration diagram showing a hybrid truck on which the regeneration control device of this embodiment is mounted.
The hybrid type truck 1 is configured as a so-called parallel type hybrid vehicle, and may be referred to as a vehicle in the following description. A vehicle 1 is equipped with a diesel engine (hereinafter referred to as an engine) 2 as a driving power source and a motor 3 that can also operate as a generator such as a permanent magnet synchronous motor. A clutch 4 is connected to the output shaft of the engine 1, and an input side of the automatic transmission 5 is connected to the clutch 4 via a rotating shaft of the motor 3. A differential device 7 is connected to the output side of the automatic transmission 5 via a propeller shaft 6, and left and right drive wheels 9 are connected to the differential device 7 via a drive shaft 8.

  The automatic transmission 5 is based on a general manual transmission and automates the engagement / disengagement operation of the clutch 4 and the switching operation of the shift speed. In this embodiment, the automatic transmission 5 has a forward speed 6-speed reverse-speed 1 speed. ing. Of course, the configuration of the transmission 5 is not limited to this, and can be arbitrarily changed. For example, the transmission 5 may be embodied as a manual transmission, or a so-called dual clutch automatic transmission having two power transmission systems. It may be embodied as a machine.

  A battery 11 is connected to the motor 3 via an inverter 10. The DC power stored in the battery 11 is converted into AC power by the inverter 10 and supplied to the motor 3 (power running control), and the driving force generated by the motor 3 is transmitted to the drive wheels 9 after being shifted by the automatic transmission 5. The vehicle 1 is made to travel. For example, when the vehicle 1 decelerates or travels on a downhill road, the motor 3 operates as a generator by reverse driving from the drive wheel 9 side (regenerative control). The negative driving force generated by the motor 3 is transmitted to the driving wheel 9 side as a braking force, and the AC power generated by the motor 3 is converted into DC power by the inverter 10 and charged to the battery 11.

  The driving force generated by the motor 3 is transmitted to the driving wheel 9 regardless of the state of connection / disconnection of the clutch 4, and the driving force generated by the engine 2 is driven only when the clutch 4 is connected. 9 side. Therefore, when the clutch 4 is disengaged, the positive or negative driving force generated by the motor 3 as described above is transmitted to the driving wheel 9 side, and the vehicle 1 travels. When the clutch 4 is connected, the driving force of the engine 2 and the motor 3 is transmitted to the driving wheel 9 side, or only the driving force of the engine 2 is transmitted to the driving wheel side, so that the vehicle 1 travels.

The vehicle ECU 13 is a control circuit for integrated control of the entire vehicle. For this purpose, the vehicle ECU 13 includes an accelerator sensor 15 that detects the operation amount θacc of the accelerator pedal 14, a brake switch 17 that detects the depression operation of the brake pedal 16, a vehicle speed sensor 18 that detects the speed V of the vehicle 1, and the rotation of the engine 2. Various sensors and switches such as an engine rotation speed sensor 19 for detecting the speed Ne and a motor rotation speed sensor 20 for detecting the rotation speed Nt of the motor 3 are connected.
The vehicle ECU 13 is connected with an actuator (not shown) for connecting / disconnecting the clutch 4 and an actuator for shifting the automatic transmission 5, and an engine ECU 22 for engine control and an inverter ECU 23 for inverter control. And a battery ECU 24 for managing the battery 11 are connected.

  The vehicle ECU 13 calculates a required torque necessary for the vehicle 1 to travel based on the accelerator operation amount θacc by the driver, and selects the travel mode of the vehicle 1 based on the required torque, the SOC of the battery 11, and the like. In this embodiment, an E / G mode that uses only the driving force of the engine 2, an EV mode that uses only the driving force of the motor 3, and an HEV mode that uses both the driving force of the engine 2 and the motor 3 are set as the traveling mode. The vehicle ECU 13 selects one of the travel modes.

  The vehicle ECU 13 converts the required torque into a torque command value to be output by the engine 2 or the motor 3 based on the selected travel mode. For example, in the HEV mode, the required torque is distributed to the engine 2 side and the motor 3 side, and torque command values for the engine 2 and the motor 3 are calculated based on the gear position at that time. In the E / G mode, the required torque is converted into a torque command value for the engine 2 based on the gear position, and in the EV mode, the required torque is converted into a torque command value for the motor 3 based on the gear speed.

  Then, the vehicle ECU 13 disconnects the clutch 4 in the EV mode and connects the clutch 4 in the E / G mode and HEV mode in order to execute the selected travel mode, and then sends a torque command value to the engine ECU 22 and the inverter ECU 23. Output as appropriate. Further, during traveling of the vehicle 1, the vehicle ECU 13 calculates a target gear position from a shift map (not shown) based on the accelerator operation amount θacc, the vehicle speed V, and the like, and the actuator 4 connects and disconnects the clutch 4 to achieve this target gear position. Executes operation and gear change operation.

  On the other hand, the engine ECU 22 executes injection amount control and injection timing control so as to achieve the travel mode and torque command value input from the vehicle ECU 13. For example, in the E / G mode and the HEV mode, the driving force is generated in the engine 2 with respect to the positive torque command value, and the engine brake is generated with respect to the negative torque command value. Further, in the EV mode, the engine 2 is stopped and held by stopping the fuel injection or is set in an idle operation state.

Further, the inverter ECU 23 drives and controls the inverter 10 so as to achieve the travel mode and the torque command value input from the vehicle ECU 13. For example, in the EV mode or HEV mode, the motor 3 is controlled by powering the positive torque command value to generate a positive driving force, and the motor 3 is regeneratively controlled to the negative torque command value. Generate negative driving force. In the E / G mode, the driving force of the motor 3 is controlled to zero.
Further, the battery ECU 24 detects the temperature of the battery 11, the voltage of the battery 11, the current flowing between the inverter 10 and the battery 11, etc., calculates the SOC of the battery 11 from these detection results, and detects this SOC. It outputs to vehicle ECU13 with a result.

  By the way, as described above, the battery 11 is charged with the electric power generated by the motor 3 during the regenerative running of the vehicle 1 on the downhill road. As described in [Problems to be Solved by the Invention], the battery 11 is charged. The charging current to is subject to thermal limitations. For this reason, when the heat generation amount H exceeds a predetermined upper limit allowable value based on the above equation (1), the regenerative control of the motor 3 must be stopped or limited even if the downhill road is continuous. As a result, there is a problem that the battery 11 cannot be charged sufficiently.

  On the other hand, the state of charge of the battery 11 by the regenerative control of the motor 3 differs depending on the slope and length of the downhill road, and the amount of heat generation H increases accordingly. Therefore, it is necessary to always appropriately suppress the charging current of the battery 11 to prevent deterioration or breakage regardless of the increase state of the heat generation amount H. Therefore, measures are taken in advance for setting a determination time and an upper limit allowable value for each of a plurality of limiting conditions, and determining the amount of heat generation H based on those limiting conditions. That is, in this case, the calorific value H is calculated from the above equation (1) at each determination time of each limiting condition, and if any one of the calorific values H exceeds the upper limit allowable value, the charging current I is The regenerative control of the motor 3 is stopped or restricted.

  In view of the above-described problems, the present inventor notices that the current I is not limited based on the heat generation amount H if the heat generation amount H of the battery 11 is continuously suppressed to the upper limit allowable value during the regeneration control of the motor 3. did. That is, if the current I is no longer limited by the heat generation amount H, a substantially constant regenerative torque can be maintained during regenerative control, so that the amount of power generation that can be secured as a whole can be increased. However, when a plurality of limiting conditions based on the heat generation amount H are set as described above, it is necessary to determine which upper limit allowable value of the heat generation amount H should be suppressed. Next, regenerative control of the motor 3 on the downhill road will be described.

  In order to suppress the heat generation amount H of the battery 11 to the upper limit allowable value during the regeneration control of the motor 3 as described above, it is optimal to satisfy the requirement regarding the heat generation amount H before starting the traveling on the downhill road. It is necessary to derive a stable motor output. For this purpose, information on downhill roads existing ahead on the road of the vehicle, specifically information on the slope of the downhill roads and the length of the downhill roads is required. Therefore, in the regenerative control device of the present embodiment, in order to acquire information on the downhill road existing ahead, as shown in FIG. 1, the navigation device 31 (downhill road information acquisition means) and the communication device 32 (downhill) are provided to the vehicle ECU 13 as shown in FIG. Slope information acquisition means) is connected.

The navigation device 31 determines the position of the vehicle on the map while the vehicle 1 is traveling based on the map data stored in its own storage area and the GPS information or VICS (registered trademark) information received via the antenna. Identify. The communication device 32 performs road-to-vehicle communication with a roadside communication system of a data center that is appropriately installed on the roadside, and performs vehicle-to-vehicle communication with other vehicles that are traveling around.
Information to be communicated varies widely, for example, map information that the vehicle does not have, road information (road curves and gradients, etc.), traffic information (congestion information, accident information, construction information, etc.), or local information (tourist spots) Or the like) from the roadside communication system or other vehicles, or conversely, such information is supplied to other vehicles.

FIG. 2 shows a motor regeneration control routine executed by the vehicle ECU 13. The vehicle ECU 13 executes the routine at predetermined control intervals while the vehicle 1 is traveling.
First, in step S2, the information on the downhill road ahead of the host vehicle is acquired using the navigation device 31 and the communication device 32 (downhill road information acquisition means). In the subsequent step S4, when there is a downhill road that can regeneratively control the motor 3, the maximum energy Emax that can be recovered on the downhill road is calculated. The maximum energy Emax is influenced by, for example, the slope of the downhill road, the length of the downhill road, the weight of the vehicle 1, the running resistance received by the vehicle 1, the maximum output of the motor 3, the capacity of the battery 11, and the SOC of the current battery 11. It is calculated based on each of these requirements.

In the subsequent step S6, the maximum output Pmax that can be output by the motor 3 by regenerative control is calculated according to the following equation (2) on the premise of the above requirements.
Pmax = Emax / T (2)
Here, T is the duration of regenerative control (traveling time on the downhill road), and is calculated from the length of the downhill road and the average vehicle speed of the vehicle 1 on the downhill road.

Further, in step S8, the average current Iav of the motor 3 necessary for achieving the maximum output Pmax while traveling on the downhill road is calculated according to the following equation (3).
Iav = Pmax / Vav × η …… (3)
Here, Vav is the average voltage of the battery 11 and η is the efficiency of the motor 3.

Thereafter, in step S10, a calorific value H (n) (n = 1 to 3) is calculated according to the following equation (4) (calorific value predicting means).
H (n) = Iav ² × Tlim (n) …… (4)
Here, Tlim (n) (n = 1 to 3) is a determination time, and as an upper limit allowable value Hlmi (n) (n = 1) as three kinds of limiting conditions for suppressing the heat generation amount H of the battery 11. ~ 3) and set.

In the present embodiment, T1, T2, and T3 are determined as the determination times Tlim (n), and an upper limit allowable value Hlmi (n) is set as an upper limit of the heat generation amount H generated in the battery 11 within these determination times Tlim (n). It has been established. During the regenerative control of the motor 3, the heat generation amount H is sequentially calculated as an integrated value within each determination time Tlim (n) by, for example, a moving average every 1 second, and the heat generation amount H based on any of the limiting conditions corresponds to the upper limit allowable When the value Hlmi (n) is exceeded, the heat generation amount H is suppressed by limiting the charging current I to the battery 11.
In step S10, based on the determination time Tlim (n) and the average current Iav, the heat generation amount H (n) (predicted heat generation amount) is calculated as a predicted value of the heat generation amount H within each determination time Tlim (n). Calculated.

In subsequent step S12, each calorific value H (n) calculated as described above is compared with an upper limit allowable value Hlmi (n) (n = 1 to 3) (first calorific value determining means). When it is determined in step S12 that all the heat generation amounts H (n) do not exceed the corresponding upper limit allowable value Hlmi (n), the process proceeds to step S14. In step S14, the current Iopt corresponding to each heat generation amount H (n) is calculated according to the following equation (5) based on each heat generation amount H (n) and the corresponding determination time Tlim (n), and then calculated in step S16. The maximum value is selected from the selected current Iopt.

In step S18, a motor output is calculated based on the maximum current Iopt and the average voltage Vav of the battery 11 according to the following equation (6), and this motor output is set as the target output Pdem (target output setting means).
Pdem = Iopt × Vav / η …… (6)
The current Iopt is selected as the maximum charging current I of the battery 11 when the heat generation amount H (n) is generated under the three kinds of limiting conditions during the regeneration control of the motor 3, and the motor achieved by the current Iopt. A target output Pdem is calculated as an output. That is, the heat generation amount H (n) during the regenerative control of the motor 3 is predicted not to exceed the upper limit allowable value Hlmi (n) under any limiting condition. The maximum value is selected from the current Iopt corresponding to the amount H (n) and set as the target output Pdem.

On the other hand, when any one of the heat generation amounts H (n) exceeds the corresponding upper limit allowable value Hlmi (n) in step S12, the process proceeds to step S20. In step S20, limiting conditions in which the heat generation amount H (n) exceeds the upper limit allowable value Hlmi (n) are selected, and the upper limit allowable value Hlmi (n) applied to these limiting conditions and the corresponding determination time Tlim. Based on (n), the current Iopt is calculated according to the following equation (7).
In the subsequent step S22, the minimum value is selected from the calculated current Iopt, and then the process proceeds to step S18, where the motor output is calculated from the minimum value current Iopt and the average voltage Vav and set as the target output Pdem (target). Output setting means).

In the processes of steps S20 and S22, for example, when the heat generation amount H (n) exceeds the upper limit allowable value Hlmi (n) under all the limiting conditions, the smallest value is selected from the currents Iopt calculated under the respective limiting conditions. The When the heat generation amount H (n) exceeds the upper limit allowable value Hlmi (n) under only one limiting condition, the current Iopt for the limiting condition is selected.
The current Iopt is controlled to the upper limit allowable value Hlmi (n) under the limit condition that the heat generation amount H (n) is determined to exceed the upper limit allowable value Hlmi (n) during the regeneration control of the motor 3. The smallest possible charging current I of the battery 11 is selected. Further, the target output Pdem is calculated as the motor output achieved by the selected minimum current Iopt.

  In other words, it is not necessary to suppress the heat generation amount H with respect to a limiting condition in which the heat generation amount H (n) does not exceed the upper limit allowable value Hlmi (n). However, with regard to the limiting condition where the heat generation amount H (n) exceeds the upper limit allowable value Hlmi (n), at least up to the upper limit allowable value Hlmi (n) equivalent value in order to suppress the heat generation amount H to the upper limit allowable value Hlmi (n). It is necessary to limit the current Iopt. Further, when there are a plurality of restriction conditions that require suppression of the heat generation amount H, the restriction conditions on the side that requires the restriction of the current Iopt for suppressing the heat generation amount H (the side where the current Iopt is small) are satisfied. Since it is necessary, the minimum current Iopt is selected.

  After setting the target output Pdem as described above, the vehicle ECU 13 proceeds from step S18 to step S22 to determine whether or not the vehicle 1 has reached the downhill road. If the determination in step S22 is Yes, the motor 3 is regeneratively controlled based on the target output Pdem in step S24 (motor output control means). In a succeeding step S26, it is determined whether or not the downhill road is finished, and the process of the step S24 is repeated while the determination of No is made. If the determination in step S26 is Yes due to the end of the downhill road, the routine ends.

Next, the execution state of the regeneration control of the motor 3 on the downhill road by the vehicle ECU 13 will be described based on the time chart of FIG. In the figure, the control according to the present embodiment is indicated by a thick solid line, and the control according to Patent Document 1 is indicated by a broken line.
When the vehicle 1 reaches the downhill road, the required torque on the negative side is set as shown by a thin solid line in order to maintain an appropriate vehicle speed V, a part of which is distributed as the regenerative torque by the motor 3, and the shortage is the vehicle. 1 is supplemented by a braking device equipped with. Examples of the braking device for the vehicle 1 include a compression release brake, an exhaust brake, a retarder, and the like of the engine 2. At this time, the clutch 4 may be connected or disconnected. When the clutch 4 is disconnected, the engine 2 is idled. When the clutch 4 is connected, the engine 2 is fuel-cut. Motoring operation is performed by reverse driving from the drive wheel 9 side.

  First, the regenerative control state of the motor 3 according to Patent Document 1 will be described. As shown by the broken line, at the beginning of the regenerative control, the motor 3 is controlled at the maximum output to obtain a large regenerative torque, and the SOC is accordingly adjusted. Also increases relatively rapidly. However, when the heat generation amount H calculated from the above equation (1) approaches the upper limit allowable value, the regenerative torque of the motor 3 gradually decreases as shown by hatching to limit the charging current I to the battery 11, Along with this, the increase in SOC becomes slow. For this reason, it can be seen that the SOC does not increase so much even at the end of traveling on the downhill road.

  This embodiment indicated by a thick solid line shows a case where it is determined in step S12 that any one of the heat generation amounts H (n) (at least the heat generation amount H (2)) exceeds the upper limit allowable value Hlmi (n). In this case, the current Iopt corresponding to the upper limit allowable value Hlmi (2) is selected as the minimum value in steps S20 and S22, and the motor output is controlled based on the target output Pdem obtained from the current Iopt. Therefore, the amount of heat generation H (2) during the regeneration control of the motor 3 increases to the vicinity of the upper limit allowable value Hlmt (2), and then saturates and continues to be maintained near the upper limit allowable value Hlmt (2).

  At this time, since the other heat generation amounts H (1) and H (3) are sufficiently lower than the upper limit allowable values Hlmt (1) and Hlmt (3), it is not necessary to suppress the current I any more. On the other hand, if the current I is further increased, the heat generation amount H (2) exceeds the upper limit allowable value Hlmt (2), so that the current I is forcibly limited based on the restriction condition of the heat generation amount H. Therefore, the current I at this time is kept at the maximum value that is not restricted based on the restriction condition of the heat generation amount H.

  And compared with the case of patent document 1, in the case of this embodiment, although the regenerative torque is slightly reduced at the beginning of the regenerative control, the charging current I of the battery 11 is restricted based on the restriction condition of the heat generation amount H. Disappear. As a result, a substantially constant regenerative torque is maintained during regenerative control of the motor 3, and the amount of power generation that can be ensured as a whole increases, so that the SOC of the battery 11 increases to a higher value at the end of the downhill road. Moreover, since the torque shock resulting from the restriction | limiting of the charging current I can be prevented, the drivability of the vehicle 1 improves.

On the other hand, if all the heat generation amounts H (n) do not exceed the upper limit allowable value Hlmi (n) in step S12, the maximum value is selected from the current Iopt corresponding to each heat generation amount H (n) in steps S14 and S16. To control the motor output. Although the control status is not illustrated, in this case, since the current I is not limited based on the limit condition of the heat generation amount H, there is no problem even if the motor output is controlled based on the maximum current Iopt. As a result, even in this case, as much power generation as possible is ensured while traveling downhill.
Therefore, according to the regenerative control device for the hybrid truck 1 of the present embodiment, the kinetic energy or position of the vehicle 1 is prevented while preventing the battery 11 from being deteriorated or damaged due to excessive charging during traveling on a downhill road or the like. The battery 11 can be charged by efficiently converting energy into electric power, thereby improving the energy efficiency of the entire vehicle.

  By the way, in the first embodiment, the current Iopt corresponding to the upper limit allowable value Hlmi (n) or the heat generation amount H (n) is maintained during the regenerative control of the motor 3, so that the current I based on the restriction condition of the heat generation amount H is maintained. However, it is not always necessary to maintain the substantially constant current I. Since the calorific value H is sequentially calculated as an integrated value within each determination time Tlim (n) by moving average as described above, if these integrated values do not exceed the upper limit allowable value Hlmi (n), regenerative control is in progress. In addition, even when the current I and the motor output are varied, the forcible limitation of the current I based on the above-described limiting conditions can be avoided.

On the other hand, it is rare that the running on the downhill road ends at the timing coincident with the passage of each judgment time Tlim (n). In most cases, the running on the downhill road is in the middle of each judgment time Tlim (n). finish. For example, when the judgment time Tlim (n) = T1, the timing coincides with the time points when T1, T1 × 2, and T1 × 3 have elapsed from the start of traveling on the downhill road (the count time Tlim (n) starts counting). It is rare that the run ends. In most cases, traveling on the downhill road is completed at any timing during the period of 0 to T1, the period of T1 to T1 × 2, and the period of T1 × 2 to T1 × 3.
In view of the above points, if the motor output is controlled to be higher in the first half of the determination time Tlim (n) than in the second half of the determination time Tlim (n), the road on the downhill road is in the middle of the determination time Tlim (n). It can be seen that a greater amount of power generation can be secured when the travel is finished (the regeneration control of the motor 3 is finished). Based on the above knowledge, another example in which the motor output is varied during the regeneration control of the motor 3 will be described as a second embodiment.

[Second Embodiment]
As described above, the feature of the present embodiment is that the motor output is varied during the regeneration control. The basic configuration explained based on FIG. 1 and the processing of the vehicle ECU 13 explained based on FIG. 2 are the first embodiment. No difference. Therefore, the description of the common parts will be omitted, and the differences will be emphasized.
FIG. 4 is a time chart showing the execution state of the regeneration control of the motor 3 on the downhill road by the vehicle ECU 13, and FIG. 5 is a time chart showing the fluctuation state of the motor output during the regeneration control. In addition, since FIG. 5 represents a motor output as an electric power generation amount, it has the relationship upside down with the regenerative torque of FIG. 4, but both represent the same characteristic.

As indicated by the alternate long and short dash line in FIG. 5, in the first embodiment, the motor output is controlled to be substantially constant so as to achieve the target output Pdem set in step S18 of FIG. In the embodiment, as shown by a thick solid line, the target output is corrected to the increase side in the first half of the determination time Tlim (n), and the target output Pdem is corrected to the decrease side in the second half of the determination time Tlim (n) (target output correction means) The motor output is controlled based on the corrected target output Pdem (motor output control means).
Specifically, in this example, when traveling on a downhill road is started at point a in FIG. 5, the target output Pdem is substantially reduced from a predetermined value on the increase side to a predetermined value on the decrease side while the determination time Tlim (n) elapses. The target output Pdem is corrected so as to change at a constant change rate. If the downhill road continues after the determination time Tlim (n) elapses, the determination time Tlim (n) starts counting again and the same correction is repeated.

As the determination time Tlim (n), the determination time Tlim (n) of the limiting condition in which the minimum current Iopt is selected is applied, and the determination time Tlim (n) is set as one cycle and the target output Pdem is set as described above. Correction may be performed.
The two predetermined values on the increase side and the decrease side are set to have the same deviation around the target output Pdem before correction. Therefore, by controlling the motor output based on the corrected target output Pdem, almost the same amount of power generation as in the first embodiment can be obtained when the first determination time Tlim (n) has elapsed. This is the same even when the second or third determination time Tlim (n) has elapsed.

However, as shown by points b and c in FIG. 5, in most cases, traveling on the downhill road ends in the middle of the determination time Tlim (n). In these cases, the motor output is increased in the first half compared to the second half of the determination time Tlim (n), and as shown in FIG. 4, the battery is compared with the first embodiment at the end of the downhill road. The SOC of 11 can be further increased. This point is apparent even when the hatched areas in FIG. 5 are compared, and it can be estimated that the amount of power generation is increased since the hatched area on the increasing side is larger than the decreasing side.
Therefore, according to the regenerative control device for the hybrid truck of the second embodiment, it is possible to secure a larger amount of power generation while avoiding the limitation of the current I based on the limitation condition of the heat generation amount H.

  The correction process of the target output Pdem is not limited to the second embodiment, and may be performed as shown in FIG. 6, for example. In this example, the target output is corrected to an approximately constant value on the increase side in the first half of the determination time Tlim (n), and is corrected to an approximately constant value on the decrease side in the latter half of the determination time Tlim (n) (target output). Correction means). Even in such a case, the same effect as the second embodiment can be obtained.

When the control example of FIG. 5 is compared with the control example of FIG. 6, in the case of FIG. 6, the high motor output is maintained in the first half of the determination time Tlim (n). When the slope is finished, it is possible to secure a larger amount of power generation than in FIG.
However, the fact that it is easy to ensure the amount of power generation means that the heat generation amount H based on the current I tends to increase. For this reason, when the heat generation amount H has already increased to some extent when the vehicle 1 reaches the downhill road, when the control example of FIG. 6 is started, the upper limit of the heat generation amount H is allowed during traveling on the downhill road. There is a possibility that the current I is limited beyond the value and the power generation amount is reduced. Further, in the control example of FIG. 6, the motor output fluctuates stepwise not only at the start / end time of the determination time Tlim (n) but also at the intermediate time of the determination time Tlim (n). Easy to do.

  In view of such advantages and disadvantages, the heat generation amount H of the battery 11 when the vehicle 1 reaches the downhill road is determined (second heat generation amount determination means), and both control examples are based on the determined heat generation amount H. You may make it switch. For example, when the heat generation amount H when the downhill road reaches exceeds a preset heat generation amount determination value, the control example of FIG. 5 is executed (target output correction means). According to this control example, the heat generation amount H is less likely to increase during traveling on the downhill road compared to the control example of FIG. 6, and thus the power generation amount can be increased while avoiding the limitation of the current I.

  Further, when the heat generation amount H when the downhill road reaches is equal to or less than the heat generation amount determination value, the control example of FIG. 6 is executed (target output correction means). Since the calorific value H is still low, even if the calorific value H is increased by execution of the control example of FIG. 6, the upper limit allowable value is not exceeded during traveling on the downhill road. Further, it is possible to secure a larger amount of power generation than the control of FIG. 5 while avoiding the limitation of the current I.

  On the other hand, for example, when the vehicle 3 shifts to the uphill road immediately after the running on the downhill road, the motor 3 is immediately switched from the regenerative control to the power running control, and the heat generation amount H of the battery 11 rapidly increases as the discharge current I increases. Therefore, when such a situation is predicted, it is desirable to suppress the heat generation amount H of the battery 11 to some extent when the traveling on the downhill road is finished. In both control examples of FIGS. 5 and 6, as the correction amount A on the increase side and the decrease side centering on the target output Pdem is reduced, the power generation amount becomes more disadvantageous (first implementation in which the motor output is substantially constant). However, the amount of heat generation H at the end of traveling on the downhill road can be suppressed.

Therefore, before the vehicle 1 reaches the downhill road, the road surface information immediately after the downhill road is acquired together with the information of the downhill road ahead of the own vehicle (downhill road information acquisition means), and the downhill road information is obtained based on the road surface information. The motor output required for the next run is predicted (motor output prediction means). As described in the second embodiment, when the target output Pdem is corrected to the increase side and the decrease side, the correction amount A is reduced as the predicted motor output increases (target output correction means).
As a result, the heat generation amount H of the battery 11 generated during traveling on the downhill road, and hence the heat generation amount H at the end of traveling on the downhill road, is suppressed. Therefore, even if the heat generation amount H of the battery 11 is increased by performing the power running control on the uphill road immediately after the downhill road, it is possible to avoid a situation where the heat generation amount H exceeds the upper limit allowable value. For this reason, the interruption of the power running control due to the restriction of the discharge current I can be prevented, and the drivability of the vehicle 1 can be improved.

This is the end of the description of the embodiment, but the aspect of the present invention is not limited to this embodiment. For example, in each of the above embodiments, the hybrid truck 1 in which the motor 3 is mounted as a driving power source in addition to the engine 2 is embodied, but may be embodied in an electric vehicle in which only the motor 3 is mounted, It may be embodied in a passenger car.
In each of the above embodiments, the heat generation amount H (n) is set to the upper limit allowable value by selecting the minimum value from the current Iopt corresponding to each upper limit allowable value Hlmi (n) and setting the target output Pdem in steps S20 and S22. It was kept near Hlmi (n) (relationship between H (2) and Hlmi (2) in FIG. 4). However, the present invention is not limited to this. For example, the heat generation amount H (n) may be suppressed to a value slightly lower than the upper limit allowable value Hlmi (n), and such a case is also included in the present invention. And

2 engine 3 motor 9 driving wheel 11 battery 13 vehicle ECU (downhill road information acquisition means, heat generation amount prediction means, first heat generation amount determination means,
(Second heat generation determination means, target output setting means, target output correction means, motor output prediction means)
23 Inverter ECU (motor output control means)
31 Navigation device (downhill road information acquisition means)
32 Communication device (downhill road information acquisition means)

After setting the target output Pdem As described above, the vehicle ECU13 determines whether the host vehicle has reached the vehicle 1 is downhill shifts from step S18 to step S2 3. When the judgment at Step S2 3 becomes to Yes, to regenerative control of the motor 3 based on the target output Pdem in step S24 (motor output control means). In a succeeding step S26, it is determined whether or not the downhill road is finished, and the process of the step S24 is repeated while the determination of No is made. If the determination in step S26 is Yes due to the end of the downhill road, the routine ends.

Claims (5)

The power of the motor equipped as a power source for travel is transmitted to the drive wheels to travel, and while traveling downhill, the motor is regeneratively controlled by reverse drive from the drive wheels to regenerate power to the battery. In the electric car to charge,
Downhill road information acquisition means for acquiring downhill road information in front of the vehicle;
Based on the downhill road information acquired by the downhill road information acquisition means, the battery at a plurality of preset determination times when traveling on the downhill road while regeneratively controlling the motor with the maximum output that can be realized. A calorific value predicting means for predicting the calorific value generated due to the charging of each,
First heat generation amount determination means for determining whether the predicted heat generation amount for each determination time predicted by the heat generation amount prediction means exceeds an upper limit allowable value set in advance corresponding to each determination time; ,
When the first heat generation amount determining unit determines that any one of the predicted heat generation amounts exceeds the corresponding upper limit allowable value, the charging current of the battery corresponding to each upper limit allowable value determined to exceed the upper limit allowable value is calculated. A target output setting means for calculating and selecting the minimum value, calculating the output of the motor based on the charging current of the minimum value, and setting it as a target output;
When the vehicle reaches the downhill road and travels on the downhill road, when it is determined by the first heat generation amount determination means that any one of the predicted heat generation amounts exceeds the corresponding upper limit allowable value And a motor output control means for controlling the output of the motor based on the target output set by the target output setting means.   The target output setting means, when the first heat generation amount determination means determines that all the predicted heat generation amounts do not exceed the corresponding upper limit allowable value, the charging current of the battery corresponding to each predicted heat generation amount The regenerative control device for an electric vehicle according to claim 1, wherein the maximum value is selected by calculating each of the values and the output of the motor is calculated based on the charging current of the maximum value and set as a target output. When the motor output calculated from the minimum charging current is set as the target output by the target output setting means so that any one of the predicted heat generation amounts exceeds the corresponding upper limit allowable value, the charging current of the minimum value is The target output is corrected to the increase side in the first half of the determination time corresponding to the selected upper limit allowable value, the target output is corrected to the decrease side in the second half of the determination time, and the correction on the increase side and the decrease side is determined. It has a target output correction means that repeats every time,
3. The electric vehicle regeneration control apparatus according to claim 1, wherein the motor output control means controls the output of the motor based on the target output corrected by the target output correction means. A second calorific value determining means for determining the calorific value of the battery when the vehicle reaches a downhill road;
The target output correcting means increases the target output to a predetermined value on the increase side within the determination time when the heat generation amount of the battery determined by the second heat generation amount determination means exceeds a preset heat generation amount determination value. When the heat generation amount determined by the second heat generation amount determination means is equal to or less than the heat generation amount determination value, the target output is set to the above value. The regenerative control device for an electric vehicle according to claim 3, wherein correction is made to a substantially constant value on the increase side in the first half of the determination time, and correction is made to a substantially constant value on the decrease side in the second half of the determination time. The downhill road information acquisition means acquires road surface information immediately after the downhill road along with the downhill road information,
Based on the road surface information immediately after the downhill road acquired by the downhill road information acquisition means, motor output prediction means for predicting the motor output required for traveling immediately after the downhill road,
The said target output correction | amendment means shrinks | reduces the correction amount of the increase side of the said target output, and the reduction | decrease side, so that the motor output estimated by the said motor output prediction means is large. Electric vehicle regeneration control device.

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