JP2016002877A - vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize desired deceleration of an electric vehicle having the grill shutter while protecting a power storage device from over-charging in a case where receivable power from the power storage device is limited, and to suppress deterioration of a longevity of the grill shutter.SOLUTION: In a case where a request for braking is received with receivable power Win from a battery limited in a state where the power is less than a given threshold, an ECU causes a grill shutter to open. Further, even if the braking request is lifted after opening the grill shutter, the ECU causes the grill shutter to remain open until a vehicular speed value Va reaches or exceeds a given value.

Description

  The present invention relates to a vehicle, and more particularly to control of a vehicle including a grill shutter.

  2. Description of the Related Art A vehicle having a shutter mechanism (hereinafter also referred to as “grill shutter”) that can be opened and closed in an air introduction path for cooling a vehicle drive device is known.

  Japanese Patent Laying-Open No. 2011-097666 (Patent Document 1) discloses a vehicle having a configuration in which the air resistance of the vehicle is reduced by closing a grille shutter during high-speed traveling. Moreover, the vehicle in Unexamined-Japanese-Patent No. 2011-097666 (patent document 1) opens a grille shutter, increases air resistance, adjusts the regenerative braking force by a motor, and prevents the deterioration of brake feeling.

JP 2011-097666 A JP 63-103754 A JP 2013-1333019 A

  When decelerating, the electric vehicle is configured to satisfy a braking request by a hydraulic brake (mechanical brake) and regenerative braking accompanied by regenerative power generation.

  The battery of the electric vehicle is provided with input restriction (acceptable (chargeable) power) for battery protection. In order to prevent overcharge, acceptable power is limited when it is near full charge.

  If the acceptable power is limited, the battery may not be able to sufficiently accept the regenerative power generated by the motor. In this case, the desired deceleration may not be obtained and the brake feeling may be deteriorated. is there. For this reason, when acceptable electric power is limited, it is conceivable to adopt a method of realizing a desired deceleration by generating a braking force by increasing the air resistance with the grill shutter open. .

  However, when such a method is employed, the frequency of opening and closing the grille shutter increases, which may shorten the durability life of the grille shutter.

  The present invention has been made to solve such a problem, and an object of the present invention is to pass the power storage device in an electric vehicle equipped with a grille shutter when the acceptable power of the power storage device is limited. While realizing a desired deceleration while protecting from charging, it is to suppress the shortening of the durability life of the grille shutter.

  A vehicle according to the present invention includes a rotating electrical machine, a power storage device that charges electric power generated in the rotating electrical machine, a shutter device configured to adjust an air amount for cooling the rotating electrical machine by opening and closing, and opening and closing of the shutter device. And a control unit for controlling. The control unit opens the shutter device when there is a braking request in a state where the acceptable power of the power storage device is limited and falls below a predetermined threshold value. The control unit maintains the shutter device in the open state until the vehicle speed exceeds a predetermined value even if the braking request after the shutter device is opened is canceled.

  In the present invention, when a braking request is made in a state where the power storage device approaches a fully charged state and the acceptable power is limited, the deceleration is increased by increasing the air resistance of the vehicle by opening the grille shutter. Let As a result, the deceleration that decreases due to the limitation on the acceptable power can be compensated, and therefore, a desired deceleration can be realized while suppressing overcharging of the power storage device. After the grill shutter is opened, even if the braking request is canceled, the open state is maintained until the vehicle speed exceeds a predetermined value, so that an excessive increase in the opening / closing operation can be suppressed, and the shortening of the durability life of the grill shutter can be suppressed. be able to.

1 is an overall block diagram of an electric vehicle according to an embodiment. FIG. 2 is a diagram showing a relationship among acceptable power Win, dischargeable power Wout and SOC of the power storage device in the vehicle of FIG. 1. It is a flowchart for demonstrating the control processing of the opening / closing operation | movement of a grille shutter.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and description thereof will not be repeated.

[Basic configuration of vehicle]
FIG. 1 is an overall block diagram of an electric vehicle according to the present embodiment. Referring to FIG. 1, vehicle 1 includes a power storage device (hereinafter also referred to as a battery) 150, a drive device 200, an ECU (Electronic Control Unit) 300 that is a control device, a radiator 400, and a grill shutter 500. Prepare.

  The battery 150 is a power storage element configured to be chargeable / dischargeable. The battery 150 can supply electric power required for traveling driving to a PCU (Power Control Unit) 250. The battery 150 includes, for example, a secondary battery such as a lithium ion battery or a nickel metal hydride battery, or a power storage element such as an electric double layer capacitor. The battery 150 is provided with a detector 152. Detector 152 is configured to detect voltage VB, current IB, and temperature TB of battery 150 and output the detected values to ECU 300.

  Drive device 200 includes PCU 250, motor generators 10, 20, engine 100 that is an internal combustion engine, and power split mechanism 30, and is provided in the engine room.

  The PCU 250 is provided with an inverter and a converter (not shown). PCU 250 controls the converter and the inverter by control signal S2 from ECU 300 to drive motor generators 10 and 20.

  The motor generators 10 and 20 receive the supply of power from the PCU 250 and generate driving force. The generated driving force is transmitted to the driving wheel 80 via the output shaft 40, the gear unit 50, and the driving shaft 70. Motor generators 10 and 20 can also perform regenerative power generation during deceleration accompanying traveling. The regenerated power is stored in the battery 150.

Driving of engine 100 is controlled by a control signal S1 from ECU 300.
The power split mechanism 30 is a power transmission device that mechanically connects the three elements of the engine 100 and the motor generators 10 and 20. In order to divide the output of engine 100 into motor generators 10 and 20, power split mechanism 30 uses any one of the three elements as a reaction force element, so that the power between the other two elements can be reduced. Enable transmission.

  The vehicle 1 is provided with a vehicle speed sensor 154 that detects the vehicle speed. The vehicle speed sensor 154 outputs the detected vehicle speed Va to the ECU 300. Further, the vehicle 1 is provided with an accelerator opening sensor 156 for detecting the accelerator opening, and a shift range detector 159 for detecting the shift range of the shift lever 158, and the detected accelerator opening Ad and the shift are detected. Range signal SFT is output to ECU 300, respectively.

  ECU 300 includes a CPU (Central Processing Unit), a storage device, and an input / output buffer, all of which are not shown in FIG. 1, and inputs signals from each sensor and the like, and outputs control signals to each device. 1 and each device are controlled. Note that these controls are not limited to processing by software, and can be processed by dedicated hardware (electronic circuit).

  ECU 300 is based on voltage VB, current IB, and temperature TB input from detector 152, the state of charge of the battery (also referred to as SOC: “State of Charge”), acceptable power Win for protecting battery 150, and The dischargeable power Wout is calculated.

  In FIG. 1, the control device is configured by using one ECU 300, but for example, for each function or control target such as a converter for PCU 250, a control device for inverter, or a control device for battery. It is good also as a structure which provides a separate control apparatus for every apparatus.

  An air introduction path for taking outside air into the engine room is formed at the front of the engine room of the vehicle 1. A radiator 400 is provided in the air introduction path of the engine room. Radiator 400 is a cooling device for cooling a driving device such as engine 100 using a cooling medium such as cooling water.

  In the air introduction path, a grill shutter 500 is provided in front of the vehicle with respect to the radiator 400. Grill shutter 500 is a shutter device, and adjusts the amount of outside air introduced into the engine room by adjusting the opening degree of a movable fin (not shown). Moreover, the air resistance of the vehicle during travel can be reduced by closing the movable fin. The movable fin is driven by the actuator device 502 based on a control signal SHT1 from the ECU 300. The angle of the movable fin is detected by the angle sensor 501 and sent to the ECU 300 as an angle signal SHT2.

  While traveling, vehicle 1 decelerates using braking force by a hydraulic brake (not shown) and regenerative braking force by motor generators 10 and 20. As described above, the motor generator generates power by regenerative braking, and the generated power is stored in the battery 150.

  Here, in order to prevent overcharge and overdischarge, the battery 150 is generally set with an input power limit (acceptable power Win) and an output power limit (dischargeable power Wout). The acceptable power Win and the dischargeable power Wout are set by the SOC as shown in FIG.

  FIG. 2 is a diagram illustrating a relationship among acceptable power Win, dischargeable power Wout, and SOC. In FIG. 2, SOC is shown on the horizontal axis, and power is shown on the vertical axis. In FIG. 2, the discharge power is shown as a positive value and the charge power is shown as a negative value. Note that the magnitude relationship of the acceptable power Win in the following description is a comparison based on absolute values.

  Referring to FIG. 2, dischargeable power Wout is set to gradually decrease from Wout_max when the SOC becomes lower than a predetermined value C1. Acceptable power Win is set so as to gradually decrease from Win_max when the SOC becomes higher than a predetermined value C2.

  As described above, when full charge approaches (when the SOC increases), the acceptable power Win is limited. In such a state, the regenerative power generated by the regenerative braking by the motor generator is limited, and the deceleration due to the regenerative braking is reduced. Get smaller. Thereby, a driver | operator's brake feeling may be impaired.

  In order to prevent such a state, it is possible to employ a technique for realizing a desired deceleration by increasing the air resistance during traveling with the grill shutter open.

  However, when such a method is adopted, the opening / closing frequency of the grill shutter increases, and the durability life of the grill shutter may be shortened.

  Therefore, in the vehicle 1 according to the present embodiment, when a braking request is made in a state where the acceptable power is limited, the grill shutter is opened to achieve a desired deceleration and to overcharge the battery. In addition, once the grille shutter is in the open state, control for suppressing an increase in the open / close frequency is performed by making it difficult to return to the closed state. Thereby, shortening of the durable life of the grille shutter can be suppressed.

  FIG. 3 is a flowchart for illustrating the control process of grill shutter 500 executed by ECU 300 in the present embodiment. Each step in the flowchart shown in FIG. 3 is realized by executing a program stored in advance in ECU 300 at a predetermined cycle. Alternatively, for some steps, it is also possible to construct dedicated hardware (electronic circuit) and realize processing.

  Referring to FIGS. 1 and 3, ECU 300 determines in step 10 (hereinafter step is abbreviated as S) whether predetermined condition 1 is satisfied. Here, the predetermined condition 1 is a condition for determining whether or not to execute the deceleration ensuring with the grill shutter 500 in the open state. Specifically, the predetermined condition 1 is, for example, that the acceptable power Win of the battery 150 is smaller than a predetermined threshold (for example, Win0 in FIG. 2) (that is, the battery 150 is predicted to be fully charged). That the vehicle speed Va detected by the vehicle speed sensor 154 is within a predetermined range, and the shift range is the B range and the accelerator operation state is OFF (the accelerator pedal is not depressed). It can be a condition that all of that is satisfied. Alternatively, the predetermined condition 1 may be that the SOC exceeds or is predicted to exceed the upper limit value indicating full charge.

  The B range of the shift range is a travel range in which the deceleration when the accelerator operation is off is set to be relatively large.

  Further, the condition that the vehicle speed Va is within the predetermined range means more specifically that the vehicle speed Va is larger than a predetermined value. When the vehicle speed is low, deceleration due to an increase in air resistance is unlikely to occur even when the grill shutter 500 is opened. Therefore, this vehicle speed condition is a condition indicating that a certain increase in deceleration can be realized by opening the grille shutter.

  If predetermined condition 1 is satisfied (YES in S10), that is, if the acceptable power Win is limited and there is a braking request, the process proceeds to S30, and ECU 300 turns on the opening request flag of grille shutter 500. Then, the process proceeds to S100.

  On the other hand, when predetermined condition 1 is not satisfied (NO in S10), the process proceeds to S20, and ECU 300 next determines whether predetermined condition 2 is satisfied.

  Here, the predetermined condition 2 is a condition for returning the grill shutter 500 once opened to the closed state. The predetermined condition 2 can be, for example, a condition that the vehicle speed Va is lower than a predetermined value or that the restriction on the acceptable power Win of the battery 150 is released.

  As for vehicle speed conditions, the air resistance is proportional to the square of the vehicle speed, so when the vehicle speed is low, the increase in deceleration due to air resistance is small, and because the regenerative power itself by the motor generator is small, the deceleration is insufficient in the first place. This is based on the low possibility that the battery 150 is overcharged. Further, the conditions for the acceptable power Win are also based on the fact that there is no limitation on the acceptable power Win, and therefore it is difficult for insufficient deceleration to occur.

  If predetermined condition 2 is satisfied (YES in S20), the process proceeds to S40, and ECU 300 turns off the opening request flag to return grill shutter 500 to the closed state. ECU 300 then advances the process to S100.

  On the other hand, when predetermined condition 2 is not satisfied (NO in S20), the process proceeds to S50, and ECU 300 maintains the current state of grill shutter 500. That is, if the grille shutter 500 is in the open state, the open request flag is kept on, and if it is in the closed state, the open request flag is kept off. ECU 300 then advances the process to S100.

  Here, in the hybrid vehicle, the engine is intermittently operated as necessary. If the engine temperature decreases while the engine is stopped, fuel consumption may deteriorate after restart. For this reason, in order to suppress such deterioration in fuel consumption, the grill shutter may be closed in order to prevent (warm-up) the temperature of the engine while the engine is stopped. However, in the present embodiment, priority is given to device protection, and even if there is a request to close the grill shutter resulting from engine warm-up requirements, the purpose is to ensure deceleration and prevent battery overcharge. The opening request of the grill shutter to be executed is executed with priority.

  Referring to FIG. 3 again, ECU 300 determines in S100 whether or not the above-mentioned opening request flag is ON. If the opening request flag is ON (YES in S100), the process proceeds to S120. Going forward, the grille shutter 500 is opened regardless of whether there is a closing request resulting from the warm-up requirement.

  On the other hand, when the open request flag is OFF (NO in S100), the process proceeds to S110, and ECU 300 determines whether or not there is a close request based on a warm-up request of engine 100. In other words, it is determined whether or not the opening request flag due to the warm-up requirement is ON.

  If the opening request flag due to the warm-up requirement is ON (YES in S110), the process proceeds to S120, and ECU 300 opens grille shutter 500. On the other hand, when the opening request due to the warm-up requirement is OFF, that is, when the closing request is made (NO in S110), the process proceeds to S130, and ECU 300 closes grille shutter 500. Thus, in the present embodiment, grill shutter 500 gives priority to the opening request due to the deceleration requirement even if there is a closing request due to the warm-up requirement.

  By performing control according to the above-described processing, in an electric vehicle equipped with a grill shutter, when it is difficult to ensure deceleration by regenerative braking due to the limited power that can be received by the battery, that is, the battery due to a braking request. When the occurrence of overcharge is expected, the grille shutter is opened to increase the air resistance during traveling to ensure deceleration. Thereby, deterioration of brake feeling can be suppressed while suppressing overcharge of the battery.

  In addition, after the grill shutter is once opened to ensure deceleration, the grill shutter is kept open until the vehicle speed exceeds a predetermined value, for example, even when the braking request is eliminated. Thus, by providing hysteresis in the closing operation of the grill shutter, it is possible to suppress frequent opening and closing operations of the grill shutter, and therefore it is possible to prevent a reduction in the durability life of the grill shutter.

  Furthermore, the battery shutter can be more appropriately protected by prioritizing the opening operation of the grill shutter for securing the deceleration over the closing operation of the grill shutter for the purpose of warming up the engine.

  In the present embodiment, a hybrid vehicle including an engine and a motor generator has been described as an example of an electric vehicle. However, another embodiment of an electric vehicle including a battery and a motor (for example, an electric vehicle, a fuel cell vehicle) Etc.).

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  DESCRIPTION OF SYMBOLS 1 Vehicle 10,20 Motor generator, 30 Power split mechanism, 40 Output shaft, 50 Gear part, 70 Drive shaft, 80 Wheel, 100 Engine, 150 Battery, 156 Accelerator opening sensor, 158 Shift lever, 159 Shift range detection part , 200 driving device, 400 radiator, 500 grill shutter, 501 angle sensor, 502 actuator.

Claims (1)

Rotating electrical machinery,
A power storage device for charging electric power generated in the rotating electrical machine;
A shutter device configured to be capable of adjusting an air amount for cooling the rotating electrical machine by opening and closing; and
A control unit for controlling opening and closing of the shutter device,
The control unit opens the shutter device when there is a braking request in a state where the acceptable power of the power storage device is limited and falls below a predetermined threshold, and after opening the shutter device, A vehicle that maintains the shutter device in an open state until the vehicle speed exceeds a predetermined value even when the braking request is canceled.

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