JP6179484B2 - Vehicle power supply control device - Google Patents

Description

  The technology disclosed herein relates to a vehicle power supply control device.

  In recent years, from the viewpoint of improving the fuel efficiency of a vehicle, an increasing number of vehicles adopt a so-called deceleration regeneration system that reduces the burden on the engine by generating power intensively when the vehicle is decelerated.

  In vehicles that employ a deceleration regeneration system, in order to charge a large amount of power generated during deceleration in a short time, apart from the lead battery (first power storage device) that has been widely used, In many cases, a lithium ion battery or an electric double layer capacitor (second power storage device) capable of rapid charge / discharge is mounted (see, for example, Patent Document 1). By mounting two types of power storage devices having different characteristics, it is possible to secure a sufficiently large charge capacity while recovering the electric power generated during deceleration without waste.

  Patent Document 1 also discloses a device including a cutoff relay that cuts off the power supply from the generator to the second power storage device when the second power storage device is abnormal.

JP 2004-328988 A

  Here, in the configuration of Patent Document 1, for example, assuming a case where the vehicle is left for a long period of time, it is considered that the voltage of the second power storage device at this time is reduced by natural discharge. When the engine is started in such a state, the amount of electric power supplied from the second power storage device to the electric load is insufficient, and the electric load may possibly malfunction. Of course, it is conceivable that the generator is driven by the engine and power is supplied from the generator to the electric load. However, in Patent Document 1, the generator and the second power storage device are always connected. Until the voltage of the device recovers, the generated power is mainly used for charging the second power storage device, resulting in an excessive burden on the first power storage device.

  The technology disclosed herein is a vehicle power supply control device equipped with two types of power storage devices, and even when the voltage of the second power storage device drops due to long-term leaving of the vehicle or the like, the burden on the first power storage device It is an object to be able to charge the second power storage device while avoiding the above.

The technology disclosed herein includes a generator that is driven by an engine to generate electric power, a first power storage device connected to an electrical load, a second power storage device capable of charging and discharging more rapidly than the first power storage device, A first intermittent unit that switches connection and disconnection between the generator and the second power storage device, a second intermittent unit that switches connection and disconnection between the generator and the first power storage device, a first power storage device, and a second power storage device This is a technique for a vehicle power supply control device including a third interrupting unit that switches between connection and disconnection and a control unit that controls states of the first, second, and third interrupting units, respectively. Then, when the ignition switch is turned on when the voltage of the second power storage device is lowered due to, for example, the vehicle being left for a long time, the control unit performs control according to the first aspect or the second aspect described below. The operation is executed.

According to the first aspect, when the ignition switch is turned on and the voltage of the second power storage device is equal to or lower than the first threshold, the control unit sets the second interrupting unit after setting the first interrupting unit to the shut-off state. Is connected and the third interrupting unit is connected to the connected state, thereby supplying generated power from the generator to the first power storage device and the electric load via the second interrupting unit, and from the first power storage device. When the second power storage device is charged via the third interrupting unit and the voltage of the second power storage device is equal to or higher than the second threshold, the third interrupting unit is turned off, while the second power storage device is on while the ignition switch is on. Even if the voltage of the device exceeds the second threshold value, the power generation by the generator is continued without bringing the first intermittent portion into the connected state, and power is generated from the generator to the first power storage device and the electric load via the second intermittent portion. Control to keep supplying power .

  According to this configuration, it is possible to charge the second power storage device while avoiding a burden on the first power storage device by the driving started by turning on the ignition switch. In addition, when the driving is finished after the voltage of the second power storage device is recovered by this charging, power can be supplied to the electric load using the second power storage device in the next driving.

According to the second aspect, when the ignition switch is turned on and the voltage of the second power storage device is equal to or lower than the first threshold value, the control unit sets the second interrupting unit after setting the first interrupting unit to the shut-off state. Is connected and the third interrupting unit is connected to the connected state, thereby supplying generated power from the generator to the first power storage device and the electric load via the second interrupting unit, and from the first power storage device. When the second power storage device is charged via the third interrupting unit and the voltage of the second power storage device is equal to or higher than the second threshold value, the third interrupting unit is set to the shut-off state, and the current consumption of the electric load is predetermined. The first interrupting part is connected and the second interrupting part is shut off after stopping the power generation by the generator under the condition that the power generation by the generator is restarted. charging the second power storage device through the first discontinuous portion To control to.

According to this configuration, it is possible to charge the second power storage device while avoiding a burden on the first power storage device by the driving started by turning on the ignition switch. In addition, when the voltage of the second power storage device is recovered by this charging, the use of the power of the second power storage device can be started at an early stage by setting the first intermittent portion during the driving. However, when the first interrupting portion is switched from the shut-off state to the connected state in a state where there is a large difference between the power generation voltage of the generator and the voltage of the second power storage device, the first interrupting portion is particularly a mechanical contact relay. When constructed, there is concern that the contacts will be damaged. Therefore, the control unit controls the power generation by the generator to be stopped before the first intermittent unit is connected to protect the contacts. Since the second intermittent unit is cut off on condition that the current consumption of the electrical load is equal to or less than a predetermined threshold, the first power storage device can continue to supply power to the electrical load with a light load, Charging of the second power storage device can be further advanced by the power generated by the generator by restarting the power generation by the generator after setting the one interrupted portion to the connected state.

  The third interrupting unit includes a semiconductor switch connected in series between the first power storage device and the second power storage device, and the control unit controls the voltage of the second power storage device during the OFF period of the semiconductor switch. It may be observed.

  According to this configuration, the control unit can observe the open circuit voltage of the second power storage device in a state where no current flows through the second power storage device. This is because an accurate voltage of the second power storage device cannot be observed during a period in which the first power storage device and the second power storage device are connected to each other via the semiconductor switch that is in the on state.

Further, when the ignition switch is turned on regardless of whether or not the voltage of the second power storage device is equal to or lower than the first threshold while the predetermined flag is set , the control unit Is applied to the field coil of the generator by applying control from the second power storage device to the generator, and the third interrupting unit is disconnected and the first interrupting unit is connected. In addition, the second power storage device may be controlled to be charged via the first intermittent portion by the generated power of the generator .

According to this arrangement, when the power of the second power storage devices, such as working on a production line, with electric power generated from the generator by rapidly charging the second power storage device, to allow shortening of production tact Become.

  According to the technology disclosed herein, in a vehicle power supply control device equipped with two types of power storage devices, even when the voltage of the second power storage device drops due to long-term leaving of the vehicle or the like, the first power storage device It is possible to charge the second power storage device while avoiding the burden.

It is a circuit diagram which shows the electric constitution of the power supply control device for vehicles. It is a block diagram which shows the connection of a control system. It is a flowchart which shows the procedure of the control performed at the time of engine starting. It is a flowchart which shows the other procedure of the control performed at the time of engine starting.

  Hereinafter, exemplary embodiments will be described in detail with reference to the drawings.

(1) Overall Configuration of Vehicle FIG. 1 is a circuit diagram showing an electrical configuration of a vehicle power supply control device. The vehicle shown in FIG. 1 has an alternator 1 that generates power by generating power from a diesel engine (not shown) provided in an engine room (hereinafter also referred to simply as an engine), and is electrically connected to the alternator 1. The battery 2 and the capacitor 3 that store the generated power, the DC / DC converter 4 that steps down the power generated by the alternator 1, the electric load 5 that includes various electrical components that consume power, and the engine that is driven when the engine is started. And a starter 6 for cranking the engine. The alternator 1 corresponds to the “generator” in the claims, the battery 2 corresponds to the “first power storage device” in the claims, and the capacitor 3 corresponds to the “second power storage device” in the claims. .

  The alternator 1 generates power by rotating a rotor that rotates in conjunction with the output shaft of an engine in a magnetic field. The alternator 1 has a range of up to 25 V depending on the increase or decrease of the current applied to the field coil that generates the magnetic field. It is possible to adjust the generated power. The alternator 1 also includes a rectifier (not shown) that converts the generated AC power into DC power. That is, the electric power generated by the alternator 1 is converted into direct current by this rectifier and then transmitted to each part.

  The battery 2 is a lead battery having a nominal voltage of 12 V, which is a common power storage device for vehicles. Since such a battery 2 stores electrical energy by a chemical reaction, it is not suitable for rapid charge / discharge, but has a characteristic that it can store a relatively large amount of power because it easily secures a charge capacity. There is.

  The capacitor 3 has a large capacity by connecting a plurality of electric double layer capacitors (EDLC), and can be charged up to 25V. Unlike the battery 2, the capacitor 3 stores electricity by physical adsorption of electrolyte ions, and therefore has a characteristic that it can be charged / discharged relatively quickly and has low internal resistance.

  The DC / DC converter 4 is of a switching type in which a voltage is changed by ON / OFF (switching operation) of a built-in switching element. In the present embodiment, the DC / DC converter 4 is configured to switch the voltage of power supplied from the alternator 1 or the capacitor 3 side to the electric load 5 or the battery 2 side (that is, from the left side to the right side in the figure) by a switching operation. It has a function to step down the voltage, but other functions such as a function to allow power supply in the opposite direction (that is, from the right side to the left side in the figure) and to increase the voltage are provided. Not done.

  The alternator 1 and the capacitor 3 are connected to each other via a first power supply line 7. A second line 8 branches from the first line 7, and a DC / DC converter 4 is interposed in the middle of the second line 8. A third line 9 branches from the second line 8, and the battery 2 and the second line 8 are connected to each other via the third line 9. A fourth line 10 branches from the third line 9, and the starter 6 and the battery 2 are connected to each other via the fourth line 10.

  A capacitor cutoff relay 12 for interrupting the connection between the alternator 1 and the capacitor 3 is provided at a portion between the branch point of the first line 7 and the second line 8 and the capacitor 3. The capacitor cut-off relay 12 corresponds to the “first intermittent portion” in the claims, and is in an on state (closed: connected state) that permits power supply from the alternator 1 to the capacitor 3 and an off state that cuts off the power supply. It is possible to switch to (open: shut-off state).

  Further, a bypass line 11 branches from the first line 7 in parallel with the second line 8, and the bypass line 11 is connected to a middle portion of the second line 8 located on the output side of the DC / DC converter 4. Has been. That is, the bypass line 11 connects the alternator 1 and the electric load 5 without using the DC / DC converter 4 and connects the battery 2 and the capacitor 3 without using the DC / DC converter 4. In order to intermittently connect these connections, the bypass line 11 is provided with a bypass relay 13. The bypass relay 13 corresponds to a “second intermittent portion” in the claims, and is in an on state (closed: connected state) that permits power feeding through the bypass line 11 (bypassing the DC / DC converter 4), It is possible to switch to an off state (open: cut-off state) that cuts off the power supply.

  The electric load 5 includes an air conditioner 22, an audio 23, and the like in addition to an electric power steering mechanism (hereinafter abbreviated as EPAS) 21 that assists a steering operation by a driver with a driving force of an electric motor or the like. Yes. The electric loads such as the EPAS 21, the air conditioner 22, and the audio 23 are supplied to the first line via the second line 8 provided with the DC / DC converter 4 or the bypass line 11 provided with no DC / DC converter 4. 7 is connected.

  Further, the electrical load 5 of the present embodiment includes a glow plug 26 in addition to the electrical load such as the EPAS 21. The glow plug 26 is a heater for warming the combustion chamber of the engine by energization heating when the engine (diesel engine in the present embodiment) is cold started. The glow plug 26 is connected to the battery 2 in parallel with the starter 6. However, the PTC heater 25 is a heater for heating the room by energization heating, and operates stably even at a maximum of 25 V. Therefore, the DC / DC Arranged on the alternator 1 and the capacitor 3 side with respect to the converter 4.

  In addition to the above, in the present embodiment, a charging line 14 that connects the battery 2 and the capacitor 3 is provided. The charging line 14 is interposed between a point on the third line 9 and a point closer to the capacitor 3 than the capacitor cutoff relay 12 in the first line 7. A charging FET 15, which is a semiconductor switch for intermittently connecting the battery 2 and the capacitor 3, is provided on the charging line 14 in series with the resistor 16. The charge FET 15 corresponds to the “third intermittent portion” in the claims, and the power supply from the battery 2 to the capacitor 3 through the charge line 14 is permitted (closed: connected state) and the power supply is cut off. It can be switched to an off state (open: shut-off state). Further, a waste power FET 17 for reducing the voltage of the capacitor 3 is provided between a connection point between the charge FET 15 and the resistor 16 and the ground.

(2) Control System FIG. 2 is a block diagram showing connection of the control system. As shown in the figure, the alternator 1, the DC / DC converter 4, the starter 6, the capacitor cutoff relay 12, the bypass relay 13, the charging FET 15, the waste electric FET 17, the electric load 5 (EPAS 21, air conditioner 22, audio 23,... ) And the like are connected to the controller 30 via various signal lines, and are controlled based on a command from the controller 30. The controller 30 is a microcomputer including a conventionally known CPU, ROM, RAM, and the like, and corresponds to a “control unit” in the claims.

  The controller 30 is connected to various sensors provided in the vehicle via signal lines. Specifically, the vehicle of the present embodiment is provided with a voltage sensor SN1, an operation state detection means SN2, an ignition switch sensor SN3, and other switch detection means SN4, and information detected by these sensors is a controller. 30 are sequentially input.

  The voltage sensor SN1 is a sensor that detects the voltage of the capacitor 3 (capacitor voltage) as shown in FIG.

  The driving state detection means SN2 is a generic term for sensors that detect physical quantities related to the state of the vehicle or engine. For example, a vehicle speed sensor that detects the traveling speed of the vehicle, an engine rotation speed sensor that detects the rotation speed of the engine, and an accelerator pedal. And an accelerator / brake sensor for detecting an operation amount or an operation force of the brake pedal. Based on the input information from the driving state detection means SN2, the controller 30 can obtain information such as whether the vehicle is decelerating or accelerating and the degree of deceleration / acceleration.

  The ignition switch sensor SN3 is a sensor that detects an operation state of an ignition switch (not shown) that is operated by a driver when the engine is started or stopped.

  The other switch detection means SN4 is a generic term for sensors that detect operation states of switches other than the ignition switch, and includes, for example, sensors that detect operation states of operation switches such as an air conditioner and an audio.

  Based on input information from each of the sensors SN1 to SN4, the controller 30 generates power generated by the alternator 1, a step-down operation by the DC / DC converter 4, driving / stopping the electric load 5 and the starter 6, and relays 12 and 13 The on / off operation, the on / off operation of the FETs 15 and 17, and the like are controlled. Hereinafter, a specific example of the control operation by the controller 30 will be described in detail.

(3) Control operation The vehicle power supply control device according to the present embodiment can execute so-called deceleration regeneration control in which power generation is concentrated when the vehicle is decelerated. For this reason, each part of a power supply is controlled as follows by the controller 30 during driving | running | working of a vehicle.

  At the time of deceleration of the vehicle, power generation by the alternator 1 is actively performed, and generated power of 25 V at maximum is generated. The electric power generated by the alternator 1 is stepped down to 12V by the DC / DC converter 4 and then supplied to the electric load 5. Further, surplus power exceeding the power consumption in the electric load 5 is supplied to the capacitor 3 and charged. Since the capacitor 3 can be rapidly charged as already described, surplus power is efficiently recovered by the capacitor 3. However, when the capacitor 3 is already in a fully charged state (25 V), the capacitor 3 cannot be charged any more, so surplus power is sent to charge the battery 2.

  On the other hand, in a driving scene other than when the vehicle is decelerating, power generation by the alternator 1 is suppressed as much as possible in order to reduce the resistance applied from the alternator 1 to the engine. For example, when power generation by the alternator 1 is not performed, power consumption in the electric load 5 is mainly provided by charging power of the capacitor 3. In other words, the maximum 25 V power charged in the capacitor 3 is stepped down to 12 V by the DC / DC converter 4 and then supplied to the electric load 5. However, when the capacitor voltage is not sufficiently high, or when the power consumption at the electric load 5 is relatively large, the power consumption at the electric load 5 cannot be covered only by the charging power of the capacitor 3. Therefore, in such a case, the power generation by the alternator 1 is performed to the minimum necessary, and the power generated by the alternator 1 is used, and the power discharged from the battery 2 is also used as necessary. . By such control, the charging power of the capacitor 3 while the vehicle is traveling is always kept above a certain level. In the present embodiment, charging / discharging of the capacitor 3 is controlled so that the capacitor voltage falls within the range of 12 to 25V.

  As described above, in this embodiment, power is supplied mainly from the alternator 1 to the electric load 5 through the DC / DC converter 4 when the vehicle is decelerated, and from the capacitor 3 through the DC / DC converter 4 except when the vehicle is decelerated. Electric power is supplied to the load 5. For this reason, during traveling of the vehicle, in principle, power feeding through the bypass line 11 is not performed, and the capacitor 3 is not disconnected from the first line 7. For this reason, the bypass relay 13 is always maintained in the cutoff state, and the capacitor cutoff relay 12 is always maintained in the connected state.

  However, when the engine is started after the vehicle has been left for a long time, it is assumed that the capacitor voltage is greatly reduced due to the spontaneous discharge of the capacitor 3. Under such circumstances, when the normal relay operation described above is executed (that is, when the bypass relay 13 is turned off and the capacitor cutoff relay 12 is turned on), the following problems occur.

  If the engine is started while the capacitor voltage is greatly reduced and the capacitor cutoff relay 12 is kept connected, even if power generation by the alternator 1 is started immediately thereafter, the generated power is naturally low in voltage. Since power is supplied to the capacitor 3, almost no power is supplied from the alternator 1 to the electric load 5. For this reason, until the capacitor 3 is fully charged and its voltage recovers (for example, until it reaches 12 V or more) (about 15 to 60 seconds), most of the power consumption in the electric load 5 is the battery 2. It will be covered by the discharge power from. At this time, since the voltage of the battery 2 (battery voltage) decreases with the large current consumption when the starter 6 is driven, the power supplied from the battery 2 to the electric load 5 must be reduced. Under such circumstances, when an electric load with relatively high power consumption, such as EPAS (Electric Power Steering Mechanism) 21, for example, operates, the battery voltage supplied to each electric load further decreases. In the worst case, a malfunction or malfunction may occur, and the voltage of the power supplied to the controller 30 may be lower than the necessary minimum voltage (the lower limit voltage necessary for normal operation of the microcomputer). There is.

  Therefore, in order to prevent such a problem, in the present embodiment, the following control is performed when the engine is started.

  FIG. 3 is a flowchart showing a control procedure performed by the controller 30 when the engine is started.

  In step S1, the controller 30 determines whether or not the ignition switch has been turned on based on the input information from the ignition switch sensor SN3 (that is, whether or not the driver has performed an operation to start the engine). As a result, in the case of YES, the controller 30 starts the engine by driving the starter 6 in step S2.

  Next, the controller 30 determines whether or not the initial mode is in step S3. If YES, the controller 30 proceeds to step S14. If NO, the controller 30 proceeds to step S4.

  Here, the initial flag that the controller 30 has will be described. When the initial flag is “1”, it means that the capacitor 3 has not yet reached a sufficiently charged state. Therefore, when the engine is started for a short time operation on the production line of the vehicle, the initial flag is “1”. The state in which the initial flag is set to “1” in this way is referred to as an initial mode in the present application. Thereafter, the initial flag is reset to “0” when the state of the capacitor 3 reaches the fully charged state for the first time by the generated power from the alternator 1. Thereafter, the initial flag is never set to “1”.

  If it is determined in step S3 that the current mode is not the initial mode and the process proceeds to step S4, the controller 30 determines whether or not the voltage of the capacitor 3, that is, the capacitor voltage Vcap is less than or equal to the threshold value Vcap1, based on the input information from the voltage sensor SN1. judge. The threshold value Vcap1 is, for example, 9V. Here, the state in which the capacitor voltage Vcap is equal to or lower than the threshold value Vcap1 is a state in which the capacitor voltage Vcap is significantly reduced (a state in which the voltage is lower than the battery voltage) due to, for example, the vehicle being left for a long period of time. . Note that the threshold Vcap1 being 9V means that the charging target voltage of the capacitor 3 is 9V in a state where the initial flag is reset to “0”. In a state where the initial flag is set to “1”, the charging target voltage of the capacitor 3 is set to a minimum voltage required for applying a current to the field coil of the alternator 1, for example, 3V.

  If the determination in step S4 is YES, the controller 30 keeps the capacitor cutoff relay 12 in the cutoff state in step S5, sets the bypass relay 13 in the connected state in step S6, and sets the field coil of the alternator 1 in step S7. An electric current is applied to cause the alternator 1 to generate power. At this time, the alternator 1 generates electricity at 12 V in order to protect the electric load 5 and the battery 2. Furthermore, the controller 30 performs the charging operation from the battery 2 to the capacitor 3 by the duty control of the charging FET 15 in step S8.

  At this time, the electric power generated by the alternator 1 is supplied to the electric load 5 and the battery 2 through the bypass relay 13 in a connected state (that is, bypassing the DC / DC converter 4). On the other hand, since the capacitor cutoff relay 12 is in the cutoff state, the power generated by the alternator 1 is not supplied to the capacitor 3. Further, due to duty control of the charge FET 15, a current flows from the battery 2 to the capacitor 3 through the charging line 14, and the capacitor 3 is charged by the battery 2. At this time, since the generated power is supplied to the battery 2 by the alternator 1, a sudden drop in the battery voltage is also suppressed.

  Next, in step S9, the controller 30 monitors the capacitor voltage Vcap while the duty of the charging FET 15 is off. Since the current flows through the capacitor 3 while the charging FET 15 is on, the capacitor voltage Vcap cannot be observed accurately. Therefore, the open voltage of the capacitor 3 is observed as an accurate capacitor voltage Vcap during the off period of the charging FET 15 where no current flows through the capacitor 3. Of course, not only the charging FET 15 but also the waste power FET 17 should be cut off during the observation of the capacitor voltage Vcap.

  Next, in step S10, the controller 30 determines whether or not the capacitor voltage Vcap is equal to or higher than the threshold value Vcap1, and returns NO to step S8 if NO, or proceeds to step S11 if YES. Here, the state where the capacitor voltage Vcap is equal to or higher than the threshold value Vcap1 is a state where the capacitor voltage Vcap is recovered to the battery voltage. Here, the same threshold value Vcap1 is adopted in step S4 and step S10, but the first threshold value in step S4 and the second threshold value in step S10 may be different from each other.

  In step S11, the controller 30 stops the duty control of the charge FET 15. This is because the capacitor voltage Vcap has recovered to the battery voltage. However, even if the charging of the capacitor 3 is completed in this way, the controller 30 controls so as to continue the cutoff state of the capacitor cutoff relay 12.

  Next, in step S12, the controller 30 determines whether or not the ignition switch has been turned off based on the input information from the ignition switch sensor SN3 (that is, whether or not the driver has performed an operation to stop the engine). Then, after waiting for the ignition switch to be turned off, the controller 30 stops the power generation by the alternator 1 in step S13. However, the controller 30 controls the capacitor cutoff relay 12 not to be in a connected state while the ignition switch is on.

  On the other hand, if it is determined in step S3 that the current mode is the initial mode, and if it is determined in step S4 that the capacitor voltage Vcap is not less than or equal to the threshold value Vcap1, the process proceeds to step S14.

  In steps S <b> 14 to S <b> 16, the controller 30 sets the capacitor cutoff relay 12 in the connected state and the bypass relay 13 in the cutoff state, and applies current to the field coil of the alternator 1 to cause the alternator 1 to generate power. Thereby, the capacitor 3 is charged by the generated power of the alternator 1 through the capacitor cutoff relay 12. Then, it progresses to above-mentioned step S12.

  When it is determined in step S3 that the current mode is the initial mode and the process proceeds to step S14, for example, the operation of learning the fuel injection amount of the diesel engine can be performed on the production line with the electric power of the capacitor 3. In a state where the initial flag is set to “1”, charging of the capacitor 3 from the battery 2 is performed while the engine is stopped, so that the voltage of the capacitor 3 is already 3 V or more when the fuel injection amount learning operation is started. The capacitor 3 can immediately apply a current to the field coil of the alternator 1. Therefore, the production tact can be shortened by rapidly charging the capacitor 3 with the generated power from the alternator 1. If the fact that the initial flag is set to “1” is displayed by blinking the specific LED, a warning can be given to the worker so as not to use an extra electrical load.

  On the other hand, if it is determined in step S4 that the capacitor voltage Vcap is not less than or equal to the threshold value Vcap1 and the process proceeds to step S14, this corresponds to a case where a new driving is started with the capacitor 3 fully charged. In this case, as a result of the control in steps S14 to S16, deceleration regenerative power generation becomes possible, and fuel efficiency can be improved.

  If it is found that the capacitor voltage Vcap is insufficient after the power generation is stopped in step S13, the battery 2 is charged from the battery 2 by performing the same control as in steps S8 to S11 while the engine is stopped. May be.

  FIG. 4 is a flowchart showing another procedure of control performed by the controller 30 when the engine is started. Steps S1 to S11 are the same as the procedure in FIG.

  According to FIG. 4, the controller 30 stops the duty control of the charging FET 15 when the capacitor voltage Vcap is restored to the battery voltage, and then the current consumption of the electric load 5 is equal to or less than the predetermined threshold value I0 in step S21. It is determined whether or not. Then, after waiting for the current consumption to become equal to or less than the threshold value I0, the controller 30 stops the power generation by the alternator 1 in step S22. Next, the process proceeds to step S23.

  The process also proceeds to step S23 if it is determined in step S3 that the current mode is the initial mode, and if it is determined in step S4 that the capacitor voltage Vcap is not less than or equal to the threshold value Vcap1.

  In steps S <b> 23 to S <b> 25, the controller 30 sets the capacitor cutoff relay 12 in the connected state and the bypass relay 13 in the cutoff state, and applies current to the field coil of the alternator 1 to cause the alternator 1 to generate power. Thereby, the capacitor 3 is charged by the generated power of the alternator 1 through the capacitor cutoff relay 12.

  Next, in step S26, the controller 30 determines whether or not the ignition switch has been turned off based on the input information from the ignition switch sensor SN3 (that is, whether or not the driver has performed an operation to stop the engine). Then, after waiting for the ignition switch to be turned off, the controller 30 stops power generation by the alternator 1 in step S27.

  If it is found that the capacitor voltage Vcap is insufficient after the power generation is stopped in step S27, the battery 2 is charged to the capacitor 3 by executing the same control as in steps S8 to S11 while the engine is stopped. May be.

(4) Operation As described above, in this embodiment, the alternator 1 that is driven by the engine to generate electric power, the battery 2 connected to the electric load 5, and the capacitor 3 that can be charged and discharged more rapidly than the battery 2 are provided. , A capacitor cutoff relay 12 that switches connection and disconnection between the alternator 1 and the capacitor 3, a bypass relay 13 that switches connection and disconnection between the alternator 1 and the battery 2, and a charge FET 15 that switches connection and disconnection between the battery 2 and the capacitor 3. And the controller 30 for controlling the states of the capacitor cutoff relay 12, the bypass relay 13, and the charging FET 15 respectively, the controller 30 is configured to control the voltage Vcap of the capacitor 3 due to long-term leaving of the vehicle or the like. The ignition switch is turned on when the When the ignition switch is turned on, control is performed so that the capacitor cutoff relay 12 is not connected when the ignition switch is on (FIG. 3), or power generation by the alternator 1 is stopped before the capacitor cutoff relay 12 is connected. (FIG. 4).

  According to FIG. 3, when the ignition switch is turned on and the voltage Vcap of the capacitor 3 is equal to or lower than the first threshold value Vcap1, the controller 30 disconnects the capacitor disconnect relay 12 and connects the bypass relay 13 and charges. By executing the control for setting the FET 15 in the connected state, the generated power is supplied from the alternator 1 to the battery 2 and the electric load 5 via the bypass relay 13 and the capacitor 3 is charged from the battery 2 via the charging FET 15 ( (Steps S5 to S11) While the ignition switch is on, power generation by the alternator 1 is continued and control is performed so that the capacitor cutoff relay 12 is not connected even when the voltage Vcap of the capacitor 3 becomes equal to or higher than the second threshold value Vcap1 (steps S5 to S11). Steps S12 to S13).

  According to this configuration, the capacitor 3 can be charged while avoiding a burden on the battery 2 by the driving, and the capacitor 3 can be used in the next drive (steps S14 to S16). Further, by maintaining the cutoff state of the capacitor cutoff relay 12 during the driving, it is not necessary to stop the alternator 1 due to the connection of the capacitor cutoff relay 12, so that it is possible to prevent the battery 2 from being burdened.

  According to FIG. 4, when the ignition switch is turned on and the voltage Vcap of the capacitor 3 is equal to or lower than the first threshold value Vcap1, the controller 30 disconnects the capacitor disconnect relay 12 and connects the bypass relay 13 to the charge. By executing the control for setting the FET 15 in the connected state, the generated power is supplied from the alternator 1 to the battery 2 and the electric load 5 via the bypass relay 13 and the capacitor 3 is charged from the battery 2 via the charging FET 15 ( When the voltage Vcap of the capacitor 3 becomes equal to or higher than the second threshold value Vcap1, the power generation by the alternator 1 is controlled to be stopped before the capacitor cutoff relay 12 is connected (step S22). To S23).

  According to this configuration, the capacitor 3 can be charged while avoiding a burden on the battery 2. Further, by connecting the capacitor cutoff relay 12, it is possible to perform decelerating regenerative power generation with respect to the capacitor 3 during the driving, thereby improving fuel consumption (steps S24 to S25).

  In addition, when the current consumption of the electric load 5 is equal to or less than the predetermined threshold value I0, the controller 30 executes control to place the capacitor cutoff relay 12 in the connected state after stopping the power generation by the alternator 1 (steps S21 to S23). ).

  According to this configuration, it is possible to minimize the burden on the battery 2 due to the stoppage of power generation when connected to the capacitor 3.

  The charge FET 15 is a semiconductor switch connected in series between the battery 2 and the capacitor 3, and the controller 30 observes the voltage of the capacitor 3 during the off period of the charge FET 15.

  According to this configuration, the voltage of the capacitor 3 can be accurately observed.

  In addition, in the initial mode in which the capacitor 3 has not yet reached a sufficiently charged state, the controller 30 controls the capacitor 3 to be charged by the alternator 1 with the capacitor cutoff relay 12 in the connected state (step S3 in FIG. 3). , S14 to S16; Steps S3 and S23 to S25 in FIG. 4).

  According to this configuration, when working on the production line with the power of the capacitor 3 in the initial mode, the production tact can be shortened by rapidly charging the capacitor 3 with the generated power from the alternator 1. .

(5) Modified Example In the above embodiment, the capacitor 3 composed of a plurality of electric double layer capacitors (EDLC) is used as the power storage device (second power storage device referred to in the claims) that can be charged and discharged more rapidly than the battery 2. However, it is also possible to use a power storage device other than the capacitor 3 as the second power storage device. One example is a lithium ion capacitor. Unlike the electric double layer capacitor, the lithium ion capacitor further improves the energy density by using a carbon-based material capable of electrochemically occluding lithium ions as the negative electrode. It is also called a hybrid capacitor because the charge / discharge principle is different (a chemical reaction is used in combination).

  In the above embodiment, the case where the technology disclosed herein is applied to a vehicle equipped with a diesel engine has been described as an example. However, the technology disclosed herein is an engine other than a diesel engine (for example, a gasoline engine). Naturally, it can also be applied to a vehicle equipped with a).

  Further, in the above embodiment, the alternator 1 is used as a generator that generates power by obtaining power from the engine. However, not only power generation but also engine torque assist (operation for adding torque to the engine output shaft) can be performed. A possible electric motor (motor generator) may be used as a generator. That is, the technique disclosed here can be applied not only to a conventional vehicle in which only the engine is a power source, but also to a hybrid vehicle using both an engine and an electric motor.

  As described above, the technology disclosed herein is useful as a vehicle power supply control device.

1 Alternator (generator)
2 Battery (first power storage device)
3 Capacitor (second power storage device)
4 DC / DC converter 5 Electric load 6 Starter 7 1st line 8 2nd line 9 3rd line 10 4th line 11 Bypass line 12 Capacitor cutoff relay (1st interruption part)
13 Bypass relay (second intermittent part)
14 Charging line 15 Charging FET (3rd intermittent part)
16 Resistance 17 Waste FET
30 controller (control unit)
SN1 Voltage sensor SN3 Ignition switch sensor

Claims (4)

A generator driven by an engine to generate electricity;
A first power storage device connected to the electrical load;
A second power storage device capable of charging and discharging more rapidly than the first power storage device;
A first intermittent unit that switches connection and disconnection between the generator and the second power storage device;
A second intermittent portion that switches connection and disconnection between the generator and the first power storage device;
A third intermittent unit that switches connection and disconnection between the first power storage device and the second power storage device;
A vehicular power supply control device including a control unit that controls the states of the first, second, and third interrupting units,
The control unit is configured to connect the second interrupting unit after the first interrupting unit is shut off when the ignition switch is turned on and the voltage of the second power storage device is equal to or lower than a first threshold. By executing control for bringing the third interrupting portion into a connected state, the generator supplies power to the first power storage device and the electric load via the second interrupting portion from the generator, and the first electricity storage When the second power storage device is charged from the device via the third interrupting unit, and the voltage of the second power storage device becomes equal to or higher than a second threshold, the third interrupting unit is turned off, while the ignition switch When the voltage of the second power storage device is equal to or higher than the second threshold value, the generator continues to generate power without connecting the first interrupting unit to the second interrupting from the generator. Through the part 1 power storage device and a vehicle power supply control device and controls to continue to supply generated power to the electric load. A generator driven by an engine to generate electricity;
A first power storage device connected to the electrical load;
A second power storage device capable of charging and discharging more rapidly than the first power storage device;
A first intermittent unit that switches connection and disconnection between the generator and the second power storage device;
A second intermittent portion that switches connection and disconnection between the generator and the first power storage device;
A third intermittent unit that switches connection and disconnection between the first power storage device and the second power storage device;
A vehicular power supply control device including a control unit that controls the states of the first, second, and third interrupting units,
The control unit is configured to connect the second interrupting unit after the first interrupting unit is shut off when the ignition switch is turned on and the voltage of the second power storage device is equal to or lower than a first threshold. By executing control for bringing the third interrupting portion into a connected state, the generator supplies power to the first power storage device and the electric load via the second interrupting portion from the generator, and the first electricity storage When the second power storage device is charged from the device via the third interrupting unit, and the voltage of the second power storage device is equal to or higher than a second threshold, the third interrupting unit is set in a shut-off state, On condition that the current consumption of the electric load is equal to or less than a predetermined threshold, after the power generation by the generator is stopped, the first intermittent portion is connected and the second intermittent portion is disconnected, and the power generation To resume power generation The vehicle power control device and controls to charge the second power storage device from the generator through the first discontinuous portion. In the vehicle power supply control device according to claim 1 or 2,
The third intermittent unit includes a semiconductor switch connected in series between the first power storage device and the second power storage device,
The vehicle power supply control device, wherein the control unit observes a voltage of the second power storage device during an OFF period of the semiconductor switch. In the vehicle power supply control device according to claim 1 or 2,
When the ignition switch is turned on regardless of whether the voltage of the second power storage device is equal to or lower than the first threshold while the predetermined flag is set , the control unit The second power storage device applies a current from the second power storage device to the field coil of the generator by executing a control in which the two interrupted parts are in the shut-off state, the third interrupted part is in the shut-off state, and the first interrupted part is in the connected state And controlling the electric power to be generated by the generator and charging the second power storage device via the first intermittent portion with the electric power generated by the generator .

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