JP4556672B2 - Vehicle regeneration control device - Google Patents

Description

  The present invention relates to a regenerative control device that is mounted on a vehicle and controls a regenerative operation during regenerative braking, and more particularly, a regenerative control device for a vehicle that includes a main battery and an auxiliary battery, and drives an electric power steering device by the auxiliary battery. About.

  In an electric vehicle or a hybrid vehicle, a regenerative braking device that assists braking by collecting the kinetic energy of the vehicle as electric power by causing the motor to function as a generator during a braking operation is used (see, for example, Patent Document 1). ).

In the technique of Patent Document 1, a situation where deceleration is required is grasped by an inter-vehicle distance sensor, a navigation system, or the like, and when deceleration is necessary, control for increasing the target value of the regenerative braking force is performed. Thus, by applying a regenerative braking force that exceeds the engine brake equivalent in a situation where deceleration is required, an appropriate deceleration can be realized without a brake operation by the driver.
JP 2001-54203 A

  By the way, in recent years, various systems for providing assisting force have been mounted on vehicles in order to reduce a driver's operation burden and operation force. Among them, a power steering device that applies an auxiliary steering force to the driver's steering force using an electric motor or the like is widely used. In electric vehicles and hybrid vehicles, an electric power steering device using an electric motor is used. And the electric motor in this electric power steering device has a large power consumption among various auxiliary machines, and the fluctuation of the used electric power is also severe. On the other hand, the battery is relatively large and heavy compared to other parts. Moreover, since it heats at the time of charging / discharging, cooling is needed, but when it is based on air cooling, ventilation etc. are needed frequently with a large sized battery. For this reason, miniaturization is desired, but in situations where the electric power steering device is operating frequently, the remaining capacity of the battery may decrease and become insufficient. There is also a possibility that the performance is lowered due to heat generation. In particular, during regenerative braking, there is a possibility that the power supply to the auxiliary battery may be insufficient, and such problems are likely to become obvious.

  Therefore, an object of the present invention is to provide a regenerative control device that can suppress an insufficient power supply to an auxiliary battery in a vehicle equipped with an electric power steering device and a regenerative braking device.

To solve the above problems, the regeneration control device for a vehicle according to the present invention, an electric power steering apparatus, a regenerative braking device, a main battery for storing electric power generated by the regenerative, electrically connected to the main to the main battery A regenerative control device for a vehicle that is charged with electric power supplied from a battery and that drives an electric power steering device with a voltage lower than that of a main battery, and predicts deviation from the lane of the host vehicle The deviation predicting means, and when the deviation predicting means is expected to deviate from the lane of the own vehicle and the regenerative braking device is driven, the charging voltage to the auxiliary battery is compared with the other cases. And charging control means for increasing.

  When deviating from the lane, it is expected that a steering operation by the driver is performed to prevent this. That is, the deviation prediction leads to the prediction of the steering operation by the driver = drive prediction of the electric power steering apparatus. In such a case, the capacity of the auxiliary battery is ensured by setting the charging voltage to the auxiliary battery higher when the regenerative braking device is driven.

  In this way, the operation of the electric power steering device by the steering operation is predicted in advance by determining the departure from the lane, and the charging voltage to the auxiliary battery is increased, so that the electric power steering is in a state where the auxiliary battery is near full charge. In order to operate the device, the shortage of power supplied to the electric power steering device is suppressed, and the steering performance of the vehicle is improved.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described in detail with reference to the accompanying drawings. In order to facilitate the understanding of the description, the same reference numerals are given to the same components in the drawings as much as possible, and duplicate descriptions are omitted.

  FIG. 1 is a block diagram of a main part of a vehicle equipped with a regeneration control device according to the present invention. This vehicle has a gasoline engine 10 and an electric motor 11 as drive sources, and these and a generator 12 which is a generator are connected by a power split mechanism 13, and an output shaft of the power split mechanism 13 is a speed reducer 19. To the drive wheel 8. Thus, a series / parallel hybrid system is adopted in which the ratio of the driving force transmitted to the driving wheel 8 by the engine 10 and the electric motor 11 is variable.

  The generator 12 and the electric motor 11 are electrically connected to a main battery 17 having a high voltage (about 300 volts) via an inverter 15 and a DC-DC converter 16. The DC-DC converter 16 is also electrically connected with a low voltage (12 volts) auxiliary battery 18. The auxiliary battery 18 is electrically connected to various auxiliary devices (such as various lights and electronic devices) including an actuator 53 of the electric power steering device 5 described later, and is used as a power supply source thereof. It has been.

  The operation of the engine 10 is controlled by an engine control computer (engine ECU) 20, and the state of the inverter 15 is controlled by a hybrid vehicle control computer (HV ECU) 21, whereby the electric power generation amount and power consumption of the electric motor 11 and the generator 12 are controlled. Adjust. This HV ECU 21 corresponds to the charge control means of the regeneration control device according to the present invention.

  Further, the inter-vehicle distance control device 3 is mounted on the vehicle. The inter-vehicle distance control device 3 includes a front camera 30 and a white line recognition ECU 31 that recognizes a division line (hereinafter referred to as a white line) that divides a traveling lane in which the host vehicle travels by image processing from the acquired image. A lane recognition device, a millimeter wave radar 32 for detecting a front obstacle, and an inter-vehicle control ECU 33 for controlling a distance between the preceding vehicle and the own vehicle based on the recognized lane and obstacle (mainly preceding vehicle) information, Consists of This inter-vehicle distance control ECU 33 corresponds to a deviation predicting means of the regenerative control device according to the present invention.

  The steering system 4 of this vehicle includes a steering wheel 40 on which a driver performs a steering operation, a steering shaft 41 that transmits the rotation of the steering wheel 40 as a rotation axis thereof, and a rack and pinion that converts the rotation of the steering shaft 41 into a reciprocating motion. A mechanism 42 and a rack bar 43 are provided, whereby the steering operation of the steering wheel 40 is transmitted to a steered wheel (not shown). On the steering shaft 41, a torque sensor 51 for detecting a steering torque is disposed, and an actuator 53 including an electric motor is connected via a speed reducer 52. The actuator 53 is electrically connected to the auxiliary battery 18 described above, and is controlled by an electric power steering computer (EPS ECU) 54. The EPS ECU 54 receives the output signals of the torque sensor 51 and the vehicle speed sensor 55 and is connected to the in-vehicle LAN 6 to transmit information to other control ECUs and the like, thereby constituting the electric power steering device 5. In addition, a navigation system (navigation system) 7 is connected to the in-vehicle LAN 6 to determine the current position of the host vehicle and the surrounding road conditions. The navigation system 7 may be a system that acquires traffic conditions and the like using inter-vehicle communication and road-to-vehicle communication.

  Next, the operation of the regeneration control device according to the present invention will be specifically described. FIG. 2 is a control flowchart of the main control of this operation. This control is executed at a predetermined timing by the HV ECU 21 in cooperation with other ECUs.

  First, the control of FIG. 2 will be described. First, information is acquired from the inter-vehicle control ECU 33 and the navigation system 7 (step S1). The inter-vehicle control ECU 33 performs the image processing of the image acquired by the white line recognition ECU 31 with the front camera 30 (for example, curvature information), the traveling direction of the host vehicle, and the lateral position in the traveling lane of the host vehicle. Then, the information such as the inter-vehicle distance from the preceding vehicle acquired by the millimeter wave radar is notified to the other control ECU by the in-vehicle LAN 6.

  Next, a determination is made of the inter-vehicle distance control state (lane keeping assist mode) and the regenerative enabled state (step S2). Whether the vehicle is in the inter-vehicle distance control state may be determined based on the information received from the inter-vehicle control ECU 33. Whether or not regeneration is possible may be determined by whether or not the temperature of the main battery 17 is within a normal range and the diagnosis result is also normal.

  If it is determined that the vehicle is in the inter-vehicle distance control state and is in a regenerative state, the process proceeds to step S3 and the estimated expected time Time_car until the lane departure obtained by the inter-vehicle control ECU 33 is compared with the threshold value T1. When it is predicted that Time_car is equal to or less than T1, the process proceeds to step S4, and it is determined whether or not the vehicle has already deviated from the lane. In the case before departure from the lane, the charging rate SOC of the main battery 17 is further compared with the charging upper limit SOCmax2 in the inter-vehicle distance control state (step S5). If the SOC is less than SOCmax2, it is determined that charging by regeneration is possible, and the process proceeds to step S6.

  In step S6, a braking torque necessary for braking is calculated based on the curvature of the curve, the vehicle position in the lane, the vehicle speed, the acceleration / deceleration, and the like. Next, based on the information received from the navigation system 7, when the traffic ahead is congested, when it is downhill, when it is expected to enter a road with a smaller curvature, etc., it was obtained in step S 6. The braking torque is increased (step S7).

  Next, a guard is applied to the braking torque value thus obtained (step S8). Specifically, the upper limit of the braking torque value set from the current vehicle state is compared with the obtained braking torque value, and if it exceeds the upper limit, it is replaced with the upper limit value. Next, a braking torque value is set as the regenerative torque value (step S9), and a guard is applied to the regenerative torque value (step S10). By using a friction brake device (disk brake or drum brake device) not shown, a braking torque larger than the regenerative torque can be applied. Here, the regenerative torque value is set so as to be lower than the upper limit value of the regenerative torque possible by regenerative braking.

  Then, the regenerative torque value is converted into the generated power value (step S11), and the power value is guarded (step S12). This power value guard is set according to, for example, the temperature condition of the main battery 17 and the operating conditions of various devices. Thereafter, a flag F_ITUDATU_KAISEI indicating that regeneration has been performed to prevent departure is turned on (step S13). Then, the value of F_ITUDATU_KAISEI at the previous time step is determined (step S14). If it is off (indicating that the previous value was changed from off to current on), F_ITUDATU_KAISEI_RAM is turned on (step S15). Then, the steering angle at that time is substituted into θkaisei (step S16), and the process is terminated.

  If it is determined in step S2 that it is not in the inter-vehicle distance control state or is not in a regenerative state, in step S3, if it is determined that the expected time Time_car until the lane departure exceeds the threshold T1, in step S4, before the lane departure If it is determined that the charging rate SOC of the main battery 17 exceeds the charging upper limit SOCmax2 in S5, the process proceeds to step S17 to turn off the flag F_ITUDATU_KAISEI and perform processing. Exit. If the value at the previous time step is ON in step S14, the process ends. In this case, the previous value is held in θkaisei.

  Next, the control flow of FIG. 3 will be described. This process is executed subsequent to the process of FIG. 2 when F_ITUDATU_KAISEI_RAM is turned on by the HV ECU 21.

  First, the number of seconds that have elapsed since F_ITUDATU_KAISEI_RAM was turned on is determined (step S21). If the elapsed number of seconds is less than 10 seconds, the absolute value of the difference between the steering angle θkaisei immediately after the departure determination and the current steering angle θnow is compared with a predetermined threshold θα (step S22). If the absolute value of the difference is less than θα, it is determined that there is no departure avoidance steering by the driver, and the process proceeds to step S23. This θα may be changed according to the vehicle speed, acceleration / deceleration, road curvature and the like.

  In step S23, a flag F_DCDC_HIGH indicating that the output voltage of the DC-DC converter 16 has been set high is turned on. As a result, the output voltage of the DC-DC converter 16 (charge voltage of the auxiliary battery 18) is set to 14V, which is 0.5V higher than usual, and the process is terminated. On the other hand, if it is determined in step S21 that the number of elapsed seconds is 10 seconds or more, and if it is determined in step S22 that the absolute value of the difference is equal to or greater than θα and departure avoidance steering by the driver has been performed, step The process proceeds to S23, and both the flags F_ITUDATU_KAISEI_RAM and F_DCDC_HIGH are turned off and the process is terminated. As a result, the output voltage of the DC-DC converter 16 (charge voltage of the auxiliary battery 18) is returned to 13.5V in the normal state.

  By controlling in this way, it is expected that the driver will perform a steering operation at the time of regenerative braking and avoid lane departure, but the auxiliary battery is still in a stage before the driver actually starts steering. The charging voltage to 18 is increased by 0.5 V from the normal time. The auxiliary battery 18 supplies electric power to drive various auxiliary machines during traveling, and continues to discharge. In order to make up for this discharge power, charging is performed by supplying power from the main battery 17 via the DC-DC converter 16 in accordance with an instruction from the HV ECU 21. When a steering operation for avoiding lane departure is expected, the charging voltage is increased to shift the auxiliary battery 18 to a state that is almost fully charged before the steering.

  When the driver operates the steering wheel 40 as departure avoidance steering, the EPS ECU 54 calculates the assist steering torque to be applied based on the outputs of the torque sensor 51 and the vehicle speed sensor 55 so that the target assist steering torque can be obtained. The actuator 53 is controlled. The actuator 53 drives the steering shaft 41 via the speed reducer 52 and applies a desired assist steering torque. Thereby, the steering load by the driver is reduced.

  As described above, since the charging voltage to the auxiliary battery 18 is increased before the avoidance steering, a decrease in the output voltage from the auxiliary battery 18 to the actuator 53 of the electric power steering device 5 is suppressed during the avoidance steering. Power can be supplied. As a result, steering responsiveness is improved, steering performance is improved, lane departure can be avoided at an early stage, and safety is also improved.

  In the case of departure avoidance steering, it is expected that the amount of steering is larger than that of a normal steering operation, and the amount of change over time is also increased. In this case, the assist steering force also increases and the power consumption of the actuator 53 also increases. However, the avoidance steering operation does not continue for a long time. Providing a large-capacity auxiliary battery 18 in anticipation of this avoids an increase in weight due to an increase in battery size and an increase in power loss due to natural discharge or the like. Connected. On the other hand, supplying the high voltage of the main battery 17 directly to the actuator 53 is impossible due to the necessity of adding a high-voltage power line in the vehicle and the specifications of the actuator 53. Moreover, even if it converts into a low voltage via the DC-DC converter 16, it is necessary to enlarge the output electric power capacity | capacitance and to respond to the time fluctuation of output electric power.

  According to the present embodiment, when the actuator 53 is expected to be driven with high power, the charging voltage can be increased in advance to ensure necessary power, so that the auxiliary battery 18 is enlarged. There is no need, and the capacity can be optimized including other auxiliary machines, and a compact one is sufficient. In addition, it is not necessary to add wiring and equipment considering high voltage, and it is not necessary to change the specifications of the DC-DC converter 16 and the like, so that the apparatus configuration is not complicated.

  In the above description, the configuration having the navigation system has been described. However, the navigation system is not indispensable for the present invention, and may be configured without this. In addition, the radar apparatus is not an essential component for determining lane departure, and it is also possible to use only image recognition. Alternatively, a marker using magnetism or the like may be arranged in the traveling lane, and the marker may be detected to determine lane departure. Alternatively, it is possible to determine lane departure using a navigation system instead of an image recognition device or a radar device.

It is a block block diagram of the principal part of the vehicle carrying the regeneration control apparatus which concerns on this invention. It is a control flowchart of the main control of the apparatus of FIG. It is a control flowchart of the control following FIG. 2 of the apparatus of FIG.

Explanation of symbols

  3 ... inter-vehicle distance control device, 4 ... steering system, 5 ... electric power steering device, 7 ... navigation system, 8 ... drive wheel, 10 ... gasoline engine, 11 ... electric motor, 12 ... generator, 13 ... power split mechanism, 15 Inverter, 16 DC-DC converter, 17 Main battery, 18 Auxiliary battery, 19 Reducer, 20 Engine ECU (Engine control computer), 21 HV ECU (Hybrid vehicle control computer), 30 Front Camera, 31 ... White line recognition ECU, 32 ... Millimeter wave radar, 33 ... Inter-vehicle control ECU, 40 ... Steering wheel, 41 ... Steering shaft, 42 ... Rack and pinion mechanism, 43 ... Rack bar, 51 ... Torque sensor, 52 ... Deceleration Machine, 53 ... actuator (electric motor), 5 ... EPS ECU (electric power steering computer), 55 ... vehicle speed sensor.

Claims (1)

An electric power steering device, a regenerative braking device, a main battery that stores power generated by regenerative power, and is electrically connected to the main battery and charged by electric power supplied from the main battery, and lower than the main battery An auxiliary battery for driving the electric power steering device with voltage, and a vehicle regeneration control device comprising:
Deviation prediction means for predicting deviation from the lane of the own vehicle,
Charge control means for increasing the charge voltage to the auxiliary battery as compared with other cases when the departure prediction means predicts a departure from the lane of the host vehicle and the regenerative braking device is driven. When,
A vehicle regenerative control device comprising:

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