JP2009061850A - Hybrid vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hybrid vehicle in which storage battery deterioration is not promoted and an electric storage amount does not decrease even when the batteries are repeatedly charged and discharged under high temperature conditions in summer or the like. <P>SOLUTION: The hybrid vehicle comprises an internal combustion engine 1, an electric motor 2 functioning also as a generator, an electric storage means 6 electrically connected to the electric motor, a traveling mode control means 4 for switching the operation of the electric motor according to the electric storage amount of the electric storage means, and uses at least one of the internal combustion engine and the electric motor as power source according to the electric storage amount of the electric storage means. The traveling mode control means activates the electric motor in discharge traveling mode for traveling while mainly supplying power to the electric motor from the electric storage means until the lower limit of electric storage amount, which indicates availability, is detected when the electric storage means is in the state of high electric storage amount, having a high electric storage amount, and after traveling by the discharge traveling mode, activates the electric motor as the generator in charge traveling mode for traveling while mainly supplying power to the electric storage means from the electric motor until the state of the high electric storage amount is detected when the lower limit of electric storage amount is detected and the electric storage means is in the state of low electric storage amount having a low electric storage amount. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a hybrid vehicle equipped with an internal combustion engine and an electric motor and using at least one of them as a power source for traveling.

  Conventionally, this type of hybrid vehicle has been provided with a rechargeable battery as a power source for the electric motor. When the electric motor is operated by discharging from the rechargeable battery during traveling, for example, when the motor is regeneratively operated by deceleration or the like, the electric power generated by the electric motor is generated. To charge the rechargeable battery. In such a hybrid vehicle, in order to charge / discharge the rechargeable battery efficiently, charge / discharge control is performed based on the charge amount.

For example, in Patent Document 1, the terminal current of a rechargeable battery is detected, the detected terminal currents are integrated, and when the integrated value is in the vicinity of a steady value in a predetermined range, a steady mode in which charging / discharging is repeated is set. The charging amount of the rechargeable battery is managed as a discharging mode that suppresses charging and promotes discharging when larger than the value, and as a charging mode that suppresses discharging and promotes charging when smaller than the steady value.
JP-A-5-316658

  However, with such a configuration, when the vehicle is driven by an electric motor, the charge amount of the rechargeable battery is reduced and the charging mode is entered, the charging mode is increased and then the discharging mode is entered, and the driving is continued as it is. Thus, the charge mode and the discharge mode are frequently repeated.

  Depending on the type of rechargeable battery, repeated charging and discharging may promote deterioration. For example, in a general lead storage battery, when charging / discharging is repeated under a high temperature use environment, deterioration may be accelerated. As the deterioration progresses in this way, the amount of electricity stored in the storage battery decreases, and when it further advances, it becomes difficult to sufficiently store electricity. As a result, the travel distance that can be traveled by using the electric motor as a power source is shortened, and finally, such a storage battery must be discarded and replaced with a new one, which increases the maintenance cost.

  Therefore, the present invention aims to eliminate such problems.

  That is, the hybrid vehicle of the present invention includes an internal combustion engine, an electric motor that also functions as a generator, power storage means that is electrically connected to the motor, and travel mode control that switches the operation of the motor according to the amount of power stored in the power storage means. Means for driving at least one of the internal combustion engine and the electric motor according to the amount of electricity stored in the electricity storage means, wherein the travel mode control means is in a state of high electricity storage where the electricity storage means has a high electricity storage amount. Until the lower limit storage amount that can be used is detected, the electric motor is operated mainly in the discharge travel mode in which the electric power is supplied from the power storage means to the motor, and the lower limit storage amount is detected after traveling in the discharge travel mode. When the battery is in a low storage state with a low storage amount, the motor is started in a charge running mode in which power is supplied mainly from the motor to the storage means until a high storage state is detected. And wherein the actuating as machine.

  With such a configuration, since the traveling mode control means operates the electric motor in the discharge traveling mode until the lower limit storage amount is detected, the storage means is discharged, while the lower limit storage amount is detected. After that, since the electric motor is operated as a generator in the charge running mode, the power storage means is charged. As a result, it is possible to reduce the number of times of switching between charging and discharging of the power storage means, and thus it is possible to suppress deterioration over time of the power storage means.

  In order to reduce the charge / discharge switching frequency, the travel mode control means is in the charge travel mode and is in the charge travel mode until the power storage state of the power storage means is sufficient to travel a predetermined distance. It is preferable to operate the electric motor. Further, the travel mode control means is preferably in the charge travel mode, and operates the electric motor in the discharge travel mode when the power storage state of the power storage means becomes a sufficient amount of power that can travel a predetermined distance. is there.

  The present invention is configured as described above, and the traveling mode control means operates the electric motor in the discharge traveling mode and the charging traveling mode according to the amount of power stored in the power storage means. The number of times of switching can be reduced, and thus deterioration with time of the power storage means can be suppressed.

  Hereinafter, a first embodiment of the present invention will be described with reference to the drawings.

  The hybrid vehicle HV of this embodiment includes an internal combustion engine 1 and an electric motor 2 that generate a driving force required for traveling, drive wheels 3 driven by the internal combustion engine 1 and the electric motor 2, and an internal combustion engine 1 and an electric motor 2 when traveling. The electronic control device 4 that controls the operation state of the motor, the inverter 5 that is electrically connected to the electric motor 2, and the power storage means 6 that is electrically connected to the inverter 5 are provided. The internal combustion engine 1 is, for example, a gasoline engine or a diesel engine.

  The electric motor 2 generates a driving force necessary for traveling by the electric power supplied from the electric storage means 6 and is also driven by the internal combustion engine 1 or the driving wheel 3 to function as a generator by a regenerative operation. The battery 7 is charged. That is, the electric motor 2 generates a driving force by an alternating current obtained by converting the direct current from the battery 7 of the power storage means 6 by the inverter 5. On the other hand, when the electric motor 2 is driven by the driving wheel 3, for example, Thus, the battery 7 is charged by converting into direct current.

  The electronic control unit 4 controls the operating state of the internal combustion engine 1 and also controls the operating state of the electric motor 2 corresponding to the travel mode. In other words, the electronic control unit 4 calculates the fuel injection amount based on the engine speed and the load, and controls the electric motor 2 according to the travel mode using a control program for a travel mode described later. The electronic control unit 4 includes a rotation speed sensor that detects the engine speed of the internal combustion engine 1, an accelerator sensor that detects a load state according to an operation amount of an accelerator pedal, a vehicle speed sensor that detects a vehicle speed, and a power storage means 6. Each sensor such as a battery sensor for detecting the storage amount of the battery 7 is electrically connected, and at least electrically connected to the fuel control valve and the inverter of the internal combustion engine 1.

  The travel mode control program stored in the electronic control unit 4 mainly transfers power from the power storage unit 6 to the motor 2 until a lower limit storage amount that can be used when the power storage unit 6 is in a high power storage amount state where the power storage amount is high. When the electric motor 2 is operated in the discharge travel mode in which power is supplied to travel, and the lower limit power storage amount is detected after travel in the discharge travel mode, and the power storage means 6 is in the low power storage state where the power storage amount is low, the high power storage state In such a configuration, the electric motor 2 is controlled to operate as a generator in the charging travel mode in which power is supplied from the electric motor 2 to the power storage means 6 until the electric power is detected. Therefore, the electronic control unit 4 constitutes a travel mode control means.

  The high power storage amount state is a state where there is a power storage amount exceeding the lower limit power storage amount, and does not necessarily mean a fully charged state. In this case, the electric power is continuously supplied to the electric motor 2 and the distance set based on a predetermined distance, for example, the distance traveled by a general vehicle in one day, from the fully charged state to the lower limit storage amount. The lower limit storage amount is set so that the vehicle can travel at least. In addition to this, it is preferable that the lower limit charged amount matches the minimum charged amount that does not cause a problem in the battery 7. By setting the lower limit storage amount as described above, it is possible to secure a sufficient traveling distance in use from the fully charged state.

  On the other hand, the low storage amount state refers to the state of the battery 7 after the traveling in the discharge travel mode is continued and the storage amount of the battery 7 once becomes below the lower limit storage amount. The amount may be any of an amount less than or equal to the lower limit storage amount or an amount exceeding the lower limit storage amount.

  The power storage means 6 includes a charging circuit 8 that rectifies 100V alternating current, for example, and can charge the battery 7 by receiving supply of 100V alternating current from a power line such as a household outlet. The power storage means 6 is configured to measure the charging current for the battery 7 and stop charging in a fully charged state where the amount of power storage is maximized. As the battery 7, a lead storage battery is suitable. Then, the charging current and the discharging current of the battery 7 are measured, respectively, and the electric storage amount is calculated in the electronic control unit 4 based on the respective integrated current values.

  In such a configuration, when the vehicle travels, the electronic control unit 4 controls the travel mode as described below according to the state of charge of the battery 7 of the power storage means 6. When controlling the running mode, the electronic control unit 4 measures the charging current and discharging current of the battery 7 and integrates the measured charging current and discharging current, respectively, and the accumulated amount of charge in the fully charged state. (Hereinafter, referred to as the fully charged amount), the charged amount that is the remaining charged amount of the battery 7 at that time is calculated.

  When traveling is started, the storage state of the battery 7 of the storage means 6 is determined, and it is determined whether or not the storage amount has fallen below the lower storage amount from the high storage state (step S1). If it is determined that the amount of electricity stored in the battery is not less than or equal to the lower limit amount of electricity, the electronic control unit 4 operates the inverter 5 to supply power from the electricity storage means 6 to the electric motor 2 (step S2). Accordingly, the hybrid vehicle HV enters a discharge travel mode in which the battery 7 continues to be discharged, and travels by operating the electric motor 2 with the electric power from the battery 7. Note that the motor 2 is not regeneratively operated even if the vehicle is decelerated by traveling on a downhill or in the vicinity of an intersection while traveling in the discharge traveling mode. That is, in the discharge travel mode, the battery 7 is only discharged, and the battery 7 is not charged during that time.

  In this way, the vehicle 7 continues to travel only by supplying power to the electric motor 2, and when it is determined in step S <b> 1 that the charged amount of the battery 7 has become equal to or less than the lower limit charged amount, the electronic control unit 4 controls the inverter 5. Then, the power supply to the electric motor 2 is stopped and the charging travel mode is set (step S3). Accordingly, the driving force required for traveling is supplied to the drive wheels 3 by the internal combustion engine 1. Thereafter, it is determined whether or not the vehicle is in a decelerating state based on a brake operation or a change in the traveling speed of the vehicle (step S4). During the deceleration, the electric motor 2 is regenerated and the battery 7 of the power storage means 6 is charged. (Step S5). As described above, after the state of high power storage amount falls below the lower limit power storage amount, power is not supplied from the power storage means 6 to the electric motor 2, and the electric motor 2 is operated as a generator while the vehicle is decelerating. Charging is performed. The determination that the stored amount of the battery 7 has once decreased below the lower limit stored amount is stored while the traveling is continued, in other words, until the battery 7 is in a high charge state.

  In the first embodiment, as shown in FIG. 3, for example, the battery 7 is charged via the charging circuit 8 while the garage is parked on a non-use day or night, and the battery 7 is fully charged. While the vehicle starts traveling from a certain fully charged state and accelerates and continues traveling at an appropriate traveling speed (vehicle speed), the discharge traveling mode is performed. During this time, the amount of power stored in the battery 7 decreases due to discharge. Then, when the storage amount becomes equal to or lower than the lower limit storage amount, the mode is switched to the charging travel mode, and the battery 7 is charged when the vehicle starts to decelerate. Further, in this charging travel mode, while the vehicle continues traveling, traveling by the electric motor 2, that is, traveling in which the battery 7 is discharged is not performed. Therefore, in a traveling state other than the deceleration state, the amount of electricity stored in the battery 7 does not change, and the amount of electricity stored by charging in the charge traveling mode is maintained.

  In such a charge travel mode, the charge travel mode is maintained until the charge state of the battery 7 constituting the power storage means 6 is sufficient to travel a predetermined distance by one or a plurality of regenerative operations. Thus, the electric motor 2 is operated, that is, the electric motor 2 is operated as a generator by regenerative operation. Then, as a result of charging by regenerative operation, when the battery 7 has a sufficient amount of charge that can travel a predetermined distance, the motor 2 is operated by supplying power from the battery 7 by switching to the discharge travel mode. is there.

  As described above, the battery 7 is only discharged from the fully charged state until the lower limit charged amount is reached, and is not charged during that time. After the lower limit charged amount is reached, the battery 7 is charged but the motor is supplied with power. Thus, the battery 7 is not discharged, so that the number of times of switching between charging and discharging of the battery 7 can be minimized. Therefore, deterioration with time of the battery 7 of the power storage means 6 can be suppressed. Accordingly, it is possible to suppress a decrease in the distance that can be traveled using the electric motor 2, and it is possible to travel without consuming fuel during the discharge travel mode.

  Moreover, since the charging means 6 can charge the battery 7 using the electric power from a household electric power line, for example, the battery 7 is charged while parked in a garage, and is constantly charged until the hybrid vehicle HV starts to be used. Can be maintained in a state.

  Next, a second embodiment of the present invention will be described. Even in the second embodiment, the mechanical configuration of the hybrid vehicle HV is the same as that of the first embodiment described above, and is shown in FIG.

  In the second embodiment, as shown in FIGS. 4 and 5, not only the electric power stored in the battery 7 is used in the high power storage state but also the battery 7 when the vehicle travels at a reduced speed. It is the structure which charges. Therefore, in this second embodiment, when controlling the running mode, the electronic control unit 4 measures the charging current and discharging current of the battery 7 and integrates the measured charging current and discharging current, respectively. On the basis of the respective integrated values obtained and the fully charged amount in the fully charged state, the charged amount that is the remaining charged amount of battery 7 at that time is calculated.

  That is, when traveling is started, in step S101, it is determined whether or not the storage amount of the battery 7 of the storage means 6 has changed from the high storage state to the lower limit storage amount. If it is determined that the charged amount of the battery 7 is not less than or equal to the lower limit charged amount, it is determined in step S102 based on the vehicle speed or the like whether or not the vehicle is traveling at a reduced slope or traveling near the intersection.

As a result of the determination, if the vehicle is not decelerating, power is supplied from the battery 7 of the power storage means 6 to the electric motor 2 via the inverter 5 in step S103. Accordingly, the hybrid vehicle HV enters a discharge travel mode in which the battery 7 continues to be discharged, and travels by operating the electric motor 2 with the electric power from the battery 7. On the other hand, if it is determined that the vehicle is traveling at a reduced speed, the electric motor 2 is regenerated in step S104. That is, the driving force from the driving wheel 3 is applied to the electric motor 2, and the electric motor 2 is rotated by the driving force to generate electric power. Then, the generated electric power is supplied to the power storage means 6 via the inverter 5, and the battery 7 is charged during that time. In this way, the battery 7 continues to run while feeding the electric motor 2, If it is determined in step S101 that the charged amount of the battery 7 has become equal to or less than the lower limit charged amount, in step S105, the electronic control unit 4 controls the inverter 5 to stop the power supply to the electric motor 2 and enter the charging travel mode. . Accordingly, the driving force required for traveling is supplied to the drive wheels 3 by the internal combustion engine 1. Thereafter, in step S106, it is determined whether or not the vehicle is decelerating based on a brake operation or a change in the traveling speed of the vehicle. If it is determined that the vehicle is decelerating, the motor 2 is regeneratively operated in step S106. The battery 7 of the power storage means 6 is charged. As described above, after the amount of power stored in the battery 7 becomes less than or equal to the lower limit stored amount from the high power storage state, power is not supplied from the power storage means 6 to the motor 2 and the motor 2 is used as a generator while the vehicle is decelerating. The battery 7 is operated to be charged. Note that the determination that the stored amount of the battery 7 has become equal to or less than the lower limit stored amount is stored while the traveling is continued, in other words, until the battery 7 is in a high charge state.

  In the second embodiment, as shown in FIG. 5, for example, the battery 7 is charged via the charging circuit 8 while parked in a garage on a non-use day or night, and the battery 7 is not fully charged. While the vehicle is starting to travel and accelerating and continuing to travel at an appropriate travel speed (vehicle speed), the discharge travel mode is mainly implemented. When the vehicle is decelerated, the regenerative operation of the electric motor 2 is performed. carry out. Therefore, the amount of electricity stored in the battery 7 is basically reduced by discharging in the discharge traveling mode, but the battery 7 is charged by partially performing the regenerative operation of the electric motor 2 like traveling on a long downhill. It is.

  Then, when the storage amount becomes equal to or lower than the lower limit storage amount, the mode is switched to the charging travel mode, and the battery 7 is charged when the vehicle starts to decelerate. Further, in this charging travel mode, while the vehicle continues traveling, traveling by the electric motor 2, that is, traveling in which the battery 7 is discharged, is not performed in a traveling state other than the deceleration state. Therefore, in a traveling state other than the deceleration state, the amount of electricity stored in the battery 7 does not change, and the amount of electricity stored by charging in the charge traveling mode is maintained.

  Even in such a second embodiment, in the charge travel mode, the state of charge of the battery 7 constituting the power storage means 6 is sufficient to travel a predetermined distance in one or more regenerative operations. The electric motor 2 is operated in the charge travel mode until the amount of charge is reached, that is, the electric motor 2 is operated as a generator by regenerative operation. Then, as a result of charging by regenerative operation, when the battery 7 has a sufficient amount of charge that can travel a predetermined distance, the motor 2 is operated by supplying power from the battery 7 by switching to the discharge travel mode. is there.

  Therefore, the vehicle travels mainly by discharging the battery 7 from the fully charged state until the lower limit charged amount is reached. After the lower limit charged amount is reached, the battery 7 is charged, but the electric motor 2 is fed to discharge the battery 7. Therefore, the number of times of switching between charging and discharging of the battery 7 during that period can be reduced as much as possible. Therefore, deterioration with time of the battery 7 of the power storage means 6 can be suppressed. In addition, since the battery 7 is charged when the vehicle travels at a reduced speed during the discharge travel mode, the travel distance in the discharge travel mode can be increased. Accordingly, it is possible to suppress a decrease in the distance that can be traveled using the electric motor 2, and it is possible to travel without consuming fuel during the discharge travel mode.

  Moreover, since the charging means 6 can charge the battery 7 using the electric power from a household power line, for example, the battery 7 is charged while parked in a garage, and the battery 7 is always in a high charge state by the start of use of the vehicle. Can be maintained.

  In each of the above embodiments, the traveling by only the electric motor 2 has been described during the discharge traveling mode. However, the driving force of the internal combustion engine 1 is added to the driving force of the electric motor 2 according to the required torque. There may be.

  Further, in the charging travel mode, in the above-described embodiment, the description has been given of the case where the electric motor 2 is regeneratively operated by the driving force from the driving wheels 3 in the deceleration traveling and the battery 7 is charged. The electric motor 2 may be regeneratively operated by the unit (actuate as a generator) and the battery 7 may be charged. In this case, the battery 7 can be charged even in a traveling state other than the decelerating traveling, and the charged amount can be recovered within a short time.

  In addition, the specific configuration of each part is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention.

The block diagram which shows schematic structure of 1st and 2nd embodiment of this invention. The flowchart which shows the outline of the control procedure of the first embodiment. Action | operation explanatory drawing of the 1st embodiment. The flowchart which shows the outline of the control procedure of the second embodiment. Action | operation explanatory drawing of the 2nd embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Internal combustion engine 2 ... Electric motor 4 ... Electronic control device 6 ... Power storage means 7 ... Battery

Claims (3)

An internal combustion engine; an electric motor that also functions as a generator; an electric storage means that is electrically connected to the electric motor; and a travel mode control means that switches an operation of the electric motor in accordance with an electric storage amount of the electric storage means. A hybrid vehicle having at least one of an internal combustion engine and an electric motor as a power source according to the quantity,
The traveling mode control means mainly operates the electric motor in a discharge traveling mode in which the electric power is supplied from the electric storage means to the electric motor until an available lower limit electric storage amount is detected when the electric storage means is in a high electric storage amount state where the electric storage amount is high. When the lower limit storage amount is detected after running in the discharge travel mode and the storage means is in a low storage state where the storage amount is low, power is supplied mainly from the motor to the storage means until a high storage state is detected. A hybrid vehicle that operates an electric motor as a generator in charging mode.   The hybrid vehicle according to claim 1, wherein the travel mode control means operates in the charge travel mode until the travel mode control means is in the charge travel mode and the power storage state of the power storage means becomes a sufficient amount of power that can travel a predetermined distance.   2. The hybrid according to claim 1, wherein the travel mode control means operates in the discharge travel mode when the power storage state of the power storage means is sufficient to travel a predetermined distance when the travel mode control means is in the charge travel mode. vehicle.

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