JP2006211859A - Device for controlling vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To detect the deterioration of one secondary battery without causing energy loss, in a vehicle having at least two secondary batteries mounted thereon. <P>SOLUTION: An HV_ECU executes a program including a step (S200) of outputting a charging command to a traveling battery from a battery for an auxiliary unit when an ignition switch is turned on (YES in S100), a step (S400) of determining the deterioration of the battery for an auxiliary unit from current-voltage characteristics by detecting the current and voltage value of the battery for an auxiliary unit (S300), a step (S600) of outputting a command for displaying an alarm on the deterioration of the battery for an auxiliary unit when the battery is determined to be deteriorated (YES in S500), and a step (S700) of processing so as to reduce a load of an auxiliary unit. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a control device for a vehicle equipped with at least two batteries, and more particularly to a control device for a vehicle that detects the state of one of the batteries without causing energy loss.

  The vehicle is equipped with only an engine that is an internal combustion engine (for example, a known engine such as a gasoline engine or a diesel engine), or an electric motor in addition to such an engine. There is a hybrid vehicle. When the engine is started, a flywheel connected to the crankshaft is rotated by a starter motor (hereinafter referred to as a starter) to crank the engine and start the engine. At this time, in a vehicle equipped with only an engine, the starter is driven by the power of the auxiliary battery. On the other hand, in a hybrid vehicle, a starter (in this case, a motor generator may be used as a starter) is driven by the power of a traveling battery.

  When the auxiliary battery is deteriorated, in a vehicle equipped only with an engine, sufficient power is not supplied to the starter and the engine is not started. For this reason, the vehicle does not travel, and there is no problem due to deterioration of the auxiliary battery after the vehicle travels. On the other hand, when a hybrid vehicle is used to supply power to the starter with a traveling battery, the engine can be started if the traveling battery is normal even if the auxiliary battery is deteriorated. Starts running. Therefore, deterioration of the auxiliary battery may become a problem after traveling.

  That is, when the engine is started using the electric power of the traveling battery in this way, since the deterioration state of the auxiliary battery mounted on the vehicle is unknown, there is a problem due to the deterioration of the auxiliary battery during traveling. It can happen. In a vehicle equipped only with an engine, the engine is started by supplying a large current from the auxiliary battery to the starter, so the driver can easily know the deterioration of the auxiliary battery depending on whether the engine can be started or not. However, in a hybrid vehicle, the engine is started by the starter using the electric power of the traveling battery, so the driver cannot know what state the auxiliary battery is in when starting the engine.

  Japanese Patent Laid-Open No. 10-224904 (Patent Document 1) discloses a hybrid vehicle that reliably detects a deterioration state of an auxiliary battery when the engine is started and notifies the driver of the deterioration, thereby enabling smooth running thereafter. The hybrid vehicle disclosed in this publication is driven by an engine, a generator driven by the engine, a main battery storing electric power generated by the generator, and electric power from the main battery. In a hybrid vehicle that includes an electric motor and an auxiliary battery for driving the auxiliary machine and starts the engine by driving the generator with the electric power of the main battery, the deterioration of the auxiliary battery is detected when the engine is started It has a detecting means and a notifying means for notifying that when the deterioration is detected. In particular, the detection means includes a switch means for supplying a lock current from the auxiliary battery to the in-vehicle device drive motor when the engine is started, and a voltage detection means for detecting the voltage of the auxiliary battery. The deterioration is detected based on the voltage change of the auxiliary battery.

According to this hybrid vehicle, a lock current is supplied from an auxiliary battery to an in-vehicle device drive motor (for example, a power window motor) when the engine is started, and the auxiliary battery is compensated for when the voltage drops greatly within a predetermined time. Since it is automatically detected that the machine battery is in a deteriorated state and notified to the driver, subsequent smooth running is possible.
JP-A-10-224904

  However, in the deterioration detection of the auxiliary battery in the hybrid vehicle disclosed in the above-mentioned patent document, the electric power of the auxiliary battery itself is consumed for the determination of the deterioration of the auxiliary battery, which is energy efficient. It is not preferable. Such a problem is not limited to the hybrid vehicle, and may occur when the battery has at least two batteries.

  The present invention has been made to solve the above-described problems, and its object is to reduce the deterioration of one secondary battery without causing energy loss in a vehicle equipped with at least two secondary batteries. It is to provide a control device for a vehicle that can be detected.

  A control device according to a first invention controls a vehicle on which a first secondary battery that stores electric power for traveling and a second secondary battery having a lower voltage than the first secondary battery are mounted. The control device includes a control unit for charging the first secondary battery with electric power supplied from the second secondary battery, and a detection unit for detecting output power from the second secondary battery. And determining means for determining the state of the second secondary battery based on the output power of the second secondary battery detected by the detecting means when the first secondary battery is charged by the control means. Including.

  According to the first invention, for example, the first secondary battery is charged using the second secondary battery before the vehicle starts running. Based on the output power (current-voltage characteristics in the discharge state) of the second secondary battery at this time, the state of the second secondary battery (for example, whether or not the second secondary battery has deteriorated) is determined. can do. At this time, the discharge power from the second secondary battery is charged into the first secondary battery, so that power is not wasted. As a result, it is possible to provide a vehicle control device that can detect the deterioration of one of the secondary batteries without causing energy loss.

  In the control device according to the second invention, in addition to the configuration of the first invention, the determining means includes means for determining whether or not the second secondary battery has deteriorated.

  According to the second invention, it is possible to determine the deterioration of the secondary battery over time.

  In the control device according to the third invention, in addition to the configuration of the first or second invention, the detection means includes means for detecting the current value and voltage value of the second secondary battery.

  According to the third invention, the second secondary battery is used to charge the first secondary battery, and based on the current value and the voltage value of the second secondary battery, the second secondary battery The state (for example, whether or not the second secondary battery is deteriorated) can be determined.

  In the control device according to the fourth aspect of the invention, in addition to the configuration of the third aspect of the invention, the determination means determines whether the second secondary battery has deteriorated based on the current-voltage characteristics of the second secondary battery. Means for determining whether or not.

  According to the fourth invention, for example, if the voltage drop under a constant current value is significant, it can be determined that the second secondary battery has deteriorated.

  In the control device according to the fifth invention, in addition to the configuration of any one of the first to fourth inventions, the vehicle includes an internal combustion engine started by the first secondary battery, and the first secondary battery. The determination means includes means for determining the state of the second secondary battery before starting the internal combustion engine.

  According to the fifth invention, before the internal combustion engine is started and the vehicle is started, it can be determined whether or not the second secondary battery (for example, for an auxiliary machine) has deteriorated. Such an internal combustion engine started with the first secondary battery is more effective because it can start cranking and start the internal combustion engine even if the second secondary battery is deteriorated.

  In the control device according to the sixth invention, in addition to the configuration of the fifth invention, the vehicle is equipped with a mechanism for boosting the voltage of the second secondary battery and charging the first secondary battery. The determination means includes means for determining the state of the second secondary battery when the internal combustion engine is started up and the voltage of the second secondary battery is boosted to charge the first secondary battery. Including.

  According to the sixth invention, when the voltage of the second secondary battery is boosted to charge the first secondary battery, the second secondary battery is charged based on the current value and the voltage value of the second secondary battery. It is possible to determine the state of the secondary battery 2 (for example, whether or not the second secondary battery has deteriorated).

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, the same parts are denoted by the same reference numerals. Their names and functions are also the same. Therefore, detailed description thereof will not be repeated.

  A control block diagram of a hybrid vehicle according to an embodiment of the present invention will be described with reference to FIG. The present invention is not limited to the hybrid vehicle shown in FIG. It may be a hybrid vehicle having another aspect equipped with a secondary battery. Further, it may be an electric vehicle or a fuel cell vehicle. It is assumed that at least two secondary batteries are installed. Moreover, there exist a nickel metal hydride battery and a lithium ion battery as such a secondary battery.

  The hybrid vehicle includes an internal combustion engine (hereinafter simply referred to as an engine) 120 such as a gasoline engine or a diesel engine, and a motor generator (MG) 140 as drive sources. In FIG. 1, for convenience of explanation, the motor generator 140 is expressed as a motor 140A and a generator 140B (or a motor generator 140B), but the motor 140A functions as a generator depending on the traveling state of the hybrid vehicle. The generator 140B functions as a motor.

In addition to this, the hybrid vehicle transmits a power generated by the engine 120 and the motor generator 140 to the drive wheels 160, and a speed reducer 180 that transmits the drive of the drive wheels 160 to the engine 120 and the motor generator 140, and the engine 120. Power split mechanism (for example, planetary gear mechanism) 200 that distributes the generated power to two paths of drive wheel 160 and generator 140B, travel battery 220 that charges power for driving motor generator 140, and travel Inverter 240 that performs current control while converting direct current of battery 220 and alternating current of motor 140A and generator 140B, and a battery control unit (hereinafter referred to as battery ECU (Electronic Control Unit)) that manages and controls the charge / discharge state of traveling battery 220 260) and En Engine ECU controlling an operation state of the emission 120
280 and MG_ECU 300 that controls motor generator 140, battery ECU 260, inverter 240, etc., and battery ECU 260, engine ECU 280, MG_ECU 300, etc. according to the state of the hybrid vehicle are mutually managed and controlled so that the hybrid vehicle can operate most efficiently. The HV_ECU 320 and the like for controlling the entire hybrid system are included.

  In the present embodiment, bidirectional converter 242 is provided between battery for traveling 220 and inverter 240. This is because the rated voltage of the traveling battery 220 is lower than the rated voltage of the motor 140A or the motor generator 140B, and therefore when the power is supplied from the traveling battery 220 to the motor 140A or the motor generator 140B, the boost converter 242 supplies the power. Boost the pressure. Further, the power from the auxiliary battery 400 is increased to charge the traveling battery 220, or the electric power from the traveling battery 220 is decreased to charge the auxiliary battery 400.

  In FIG. 1, each ECU is configured separately, but may be configured as an ECU in which two or more ECUs are integrated (for example, MG_ECU 300 and HV_ECU 320, as shown by a dotted line in FIG. 1). An example is an integrated ECU).

  The power split mechanism 200 uses a planetary gear mechanism (planetary gear) in order to distribute the power of the engine 120 to both the drive wheel 160 and the motor generator 140B. By controlling the rotation speed of motor generator 140B, power split device 200 also functions as a continuously variable transmission. The rotational force of the engine 120 is input to the planetary carrier (C), which is transmitted to the motor generator 140B by the sun gear (S) and to the motor and the output shaft (drive wheel 160 side) by the ring gear (R).

  In a hybrid vehicle equipped with a hybrid system as shown in FIG. 1, engine 120 is started (cranked) using motor generator 140 </ b> B supplied with power from battery for traveling 220. That is, when the ignition switch is set to the start position (assuming that engine 120 is started at this time), motor generator 140B cranks engine 120 and starts engine 120. The HV_ECU 320, which is a control device according to the present invention, controls the bidirectional converter 242 to charge the traveling battery 220 from the auxiliary battery 400 when the engine 320 is started. The deterioration state of the auxiliary battery 400 is determined based on the output characteristic (battery current IB-battery voltage VB characteristic) of the auxiliary battery 400 at this time.

  With reference to FIG. 2, the control structure of the deterioration state determination process of auxiliary battery 400 executed by HV_ECU 320 will be described. In the following description, HV_ECU 320 is described as performing the deterioration state determination process of auxiliary battery 400, but may be performed by another ECU. It should be noted that this deterioration state determination process for auxiliary battery 400 is performed before engine 120 is actually cranked.

  In step (hereinafter, step is abbreviated as S) 100, HV_ECU 320 determines whether or not the ignition switch is turned on. The ignition switch is turned on when the engine 120 is cranked by the motor generator 140B. If the ignition switch is turned on (YES in S100), the process proceeds to S200. If not (NO in S100), the process returns to S100 and waits until the ignition switch is turned on.

  In S200, HV_ECU 320 outputs a charging command from auxiliary battery 400 to traveling battery 220. At this time, to bi-directional converter 242, a command for boosting the electric power supplied from auxiliary battery 400 and charging traveling battery 220 is output. At this time, engine 120 is not yet cranked by motor generator 140B, and traveling battery 220 is charged.

  At S300, HV_ECU 320 detects current value IB and voltage value VB of auxiliary battery 400. At this time, the current value IB and voltage value VB of the auxiliary battery 400 are detected from the current signal (IB signal) and voltage signal (VB signal) of the auxiliary battery 400 input to the HV_ECU 320. The auxiliary battery 400 includes a current sensor that outputs a signal corresponding to the current value IB and a voltage sensor that outputs a signal corresponding to the voltage value VB.

  At S400, HV_ECU 320 analyzes the current-voltage characteristics of auxiliary battery 400, and determines deterioration of auxiliary battery 400. At this time, the current-voltage characteristic used for determining the deterioration of the auxiliary battery 400 is an example. For example, it can be determined that the auxiliary battery 400 has deteriorated when a constant current value flows and the voltage value of the auxiliary battery 400 decreases within a predetermined time. The determination method is not limited to this.

  In S500, HV_ECU 320 determines whether or not auxiliary battery 400 has deteriorated. This determination is made based on the determination result of S400. If accessory battery 400 has deteriorated (YES in S500), the process proceeds to S600. If not (NO in S500), the process proceeds to S800.

  In S600, HV_ECU 320 outputs a deterioration warning display command indicating that auxiliary battery 400 has deteriorated. By this command, for example, a warning light provided on the instrument panel is turned on or blinked, or an alarm is output.

  In S700, HV_ECU 320 performs processing so as to reduce the load on auxiliary machine 420. For example, the use restriction flag of the compressor of the air conditioner (this compressor is assumed to be an electric type driven by the auxiliary battery 400) is set to drive the compressor in response to the use request of the air conditioner. Restrict.

  In S800, HV_ECU 320 outputs a “READY-ON” permission command indicating that the vehicle is ready to start. Thereby, for example, the “READY-ON” indicator lamp provided on the instrument panel is turned on, and the engine 120 can be started (cranking) or the motor can be started.

  An operation of the vehicle according to the present embodiment based on the above-described structure and flowchart will be described.

  In the hybrid vehicle, when the driver tries to start the vehicle (either driving by the engine 120 or motor driving may be performed) and the ignition switch is turned on (YES in S100), the battery for driving is changed from the battery for auxiliary machine 400. The charging command to 220 is output, and the auxiliary battery 400 is boosted by the bidirectional converter 242, and the traveling battery 220 is charged by the boosted electric power. At this time, auxiliary battery 400 is discharged, and a discharge current value (current value IB) and a discharge voltage value (voltage value VB) are measured and input to HV_ECU 320 (S300).

When the current-voltage characteristic (IB-VB characteristic) of auxiliary battery 400 is analyzed, for example, if the voltage drop is larger than a predetermined threshold value, it is determined that auxiliary battery 400 has deteriorated. (YES in S400 and S500). In such a case, the driver is notified that the auxiliary battery 400 has deteriorated, and processing is performed to reduce the load on the auxiliary machine 420 (S600, S700).
As described above, according to the HV_ECU that is the control device according to the present embodiment, before the vehicle starts to travel, power is supplied from the auxiliary battery to the traveling battery that uses power when starting the engine. Charge the battery. At this time, if the auxiliary battery is deteriorated, the current-voltage characteristic is different from that at the normal time. When there is a change in this characteristic, it can be determined that the auxiliary battery is deteriorated. As described above, it is possible to determine the deterioration of the auxiliary battery before the vehicle starts to travel, and it is possible to avoid the occurrence of a problem due to the deterioration of the auxiliary battery after the vehicle travels. Moreover, since the electric power of the auxiliary battery used at this time is used to charge the battery for traveling, no energy loss occurs.

  If auxiliary battery 400 is not deteriorated (NO in S500), electric power of traveling battery 220 is stepped down to bidirectional converter 242 to charge auxiliary battery 400 and return to the original state. You may do it.

  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.

It is a control block diagram of the hybrid vehicle which concerns on embodiment of this invention. It is a flowchart which shows the control structure of the program performed by HV_ECU.

Explanation of symbols

  120 Engine, 140 Motor Generator, 140A Motor, 140B Generator, 160 Drive Wheel, 180 Reducer, 200 Power Dividing Mechanism, 220 Traveling Battery, 240 Inverter, 242 Bidirectional Converter, 260 Battery ECU, 280 Engine ECU, 300 MG_ECU, 320 HV_ECU, 400 Auxiliary battery, 420 Auxiliary machine.

Claims (6)

A vehicle control device including a first secondary battery that stores electric power for traveling and a second secondary battery having a lower voltage than the first secondary battery,
Control means for charging the first secondary battery with the electric power supplied from the second secondary battery;
Detecting means for detecting output power from the second secondary battery;
The state of the second secondary battery is determined based on the output power of the second secondary battery detected by the detection means when the first secondary battery is charged by the control means. A control device for the vehicle.   The vehicle control device according to claim 1, wherein the determination unit includes a unit for determining whether or not the second secondary battery is deteriorated.   The vehicle control device according to claim 1, wherein the detection unit includes a unit for detecting a current value and a voltage value of the second secondary battery.   The vehicle according to claim 3, wherein the determination unit includes a unit for determining whether or not the second secondary battery is deteriorated based on a current-voltage characteristic of the second secondary battery. Control device. The vehicle is equipped with an internal combustion engine that is started by the first secondary battery, and a traveling motor that is driven by the first secondary battery,
The vehicle control device according to claim 1, wherein the determination unit includes a unit for determining a state of the second secondary battery before the internal combustion engine is started. The vehicle is equipped with a mechanism for boosting the voltage of the second secondary battery and charging the first secondary battery,
The determination means determines the state of the second secondary battery when boosting the voltage of the second secondary battery and charging the first secondary battery when the internal combustion engine is started. The vehicle control device according to claim 5, comprising means for

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