JP2008082275A - Battery deterioration detecting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To use a battery, other than one mainly used for driving a starter, for driving the starter auxiliarily, and to detect deterioration. <P>SOLUTION: This battery deterioration detecting device for detecting deterioration of a battery in a vehicle equipped with a main battery 16 for supplying electric power to a first electric load 26 and the starter 14, and a sub battery 18 for supplying electric power to a second electric load 30 is provided with a relay 22 for connecting the sub battery and the starter, a relay control means for connecting the starter and the sub battery through the relay when an ignition key switch 36 is turned on, and a battery deterioration detecting means for detecting deterioration of the main battery and the sub battery based on lowering behavior of battery voltages of the sub battery and the main battery connected to the starter through the relay by the relay control means occurring when the sub battery and the main battery start to supply the electric power to the starter respectively. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a vehicle battery deterioration detection device, and belongs to an engine control field in which engine control contents are changed based on a battery deterioration detection result.

  In recent years, when a restart condition is established such that the engine is automatically stopped temporarily during idling to reduce fuel consumption or carbon dioxide emissions, and then the driver starts the vehicle. Thus, an automatic engine stop control, that is, a so-called idle stop control technique that automatically restarts the engine has been developed.

  The engine restart after the automatic engine stop is simply described by driving the starter to rotate the crankshaft, and injecting fuel into the cylinder in synchronism therewith to ignite and burn.

  However, since the starter is used every time the engine is restarted in the idle stop control, the power consumption of the battery increases as compared with the case where the idle stop control is not performed. As a countermeasure, for example, there is one described in Patent Document 1. This includes a plurality of batteries, and switches to another battery when the power supply capacity of the battery used for the starter falls below a certain level.

JP 2005-36795 A

  However, the device described in Patent Document 1 has a spare battery for driving the starter, and the spare battery stands by without doing anything.

  Therefore, the present invention does not use a spare battery, but supplements a battery for driving an electrical load other than the starter (for example, an electric oil pump for a hill holder) (other than a battery mainly driven by the starter). Provided is a battery deterioration detection device that is used for driving the starter and detects a deterioration state of the battery so as not to cause a situation where power supplied to an electric load driven by the battery is insufficient. Let it be an issue.

  In order to solve the above-mentioned problem, the invention according to claim 1 of the present application includes a first electric load, a main battery that supplies power to the starter, and a sub-battery that supplies power to the second electric load. The battery deterioration detecting device for detecting battery deterioration in the above, wherein when the ignition key switch is turned on, a relay for connecting the sub battery and the starter, the starter and the sub battery are connected via the relay. The relay control means to be connected, and the respective battery voltage drops that occur when the sub-battery and the main battery connected to the starter via the relay by the relay control means start to supply power to the starter. Based on the behavior, a battery that determines deterioration of the main battery and the sub battery is determined. And having a re-deterioration determining unit.

  Further, the invention according to claim 2 is the battery deterioration detection device according to claim 1, further comprising engine temperature detection means for detecting an engine temperature, wherein the relay control means includes the engine temperature detection means. When the detected temperature is equal to or lower than a predetermined temperature, the starter and the sub-battery are configured not to be connected via the relay.

  Furthermore, the invention according to claim 3 is the battery deterioration detection device according to claim 1 or 2, wherein the battery deterioration determination means detects deterioration of at least one of the main battery or the sub battery. In some cases, the apparatus includes a deterioration notification unit that notifies the user of the deterioration of the battery.

  Furthermore, the invention according to claim 4 is the battery deterioration detection device according to any one of claims 1 to 3, wherein when the predetermined engine stop condition is satisfied, the engine is automatically stopped, Automatic stop control means for automatically starting the engine when a predetermined engine start condition is established during the stop, and the automatic stop control means detects the deterioration of the battery when the battery deterioration determination means detects battery deterioration. It is configured to prohibit automatic stop.

  According to the battery deterioration detection apparatus of the first aspect of the present invention, when the ignition key switch is turned on, the starter is driven by the main battery and the sub battery. At this time, the deterioration determination of the main battery and the sub-battery is executed based on the respective battery voltage decrease behavior that occurs when the main battery and the sub-battery start to supply power to the starter. Therefore, when the ignition key switch is turned on, the starter can be driven by the cooperation of the main battery and the sub battery even if the main battery is deteriorated. It becomes possible to detect. These are useful when the sub-battery is a battery that cannot continue to supply power to an electric load that does not allow fluctuations in the amount of power supplied after the ignition key switch is turned on and cannot be judged for deterioration after the ignition key switch is turned on. is there.

  According to the battery deterioration detection device of the second aspect, the relay temperature can be indirectly detected by detecting the engine temperature. When the relay temperature is equal to or lower than the predetermined temperature, the starter And the sub battery are not connected via a relay. This prevents damage to the relay that may occur when a large current flows from the sub-battery to the starter in the relay at a predetermined temperature or lower.

  According to the engine stop control device of the third aspect, when at least one of the main battery and the sub-battery is deteriorated, the user is notified of the battery deterioration, so that the user can be urged to replace the battery.

  Furthermore, according to the engine stop control device of the fourth aspect, when the deterioration of the battery is detected, the automatic stop of the engine is prohibited, so that the engine automatically stopped due to the deteriorated battery may not be restarted. It is suppressed.

  FIG. 1 shows a schematic configuration of an engine control apparatus that performs idle stop control according to an embodiment of the present invention. The engine control apparatus denoted by reference numeral 10 in the figure includes an engine 12, a starter 14 that assists in starting the engine 12, a main battery 16 that supplies electric power to the starter 14, and a sub battery 18. In the figure, the solid line indicates the flow of power, and the alternate long and short dash line indicates the flow of control signals and detection signals.

  The starter 14 is configured to rotate a crankshaft (not shown) of the engine 12 based on a start signal from the ECU 20.

  As will be described later, the electric power necessary for driving the starter 14 is supplied from the main battery 16 or the sub battery 18 or both batteries. The sub-battery 18 supplies power to the starter 14 via a primary relay (corresponding to a relay described in claims) 22 and a secondary relay 24 controlled by the ECU 20.

  The main battery 16 is for supplying electric power to the starter 14 and a first electric load 26 (a load that requires a large amount of electric power while allowing some fluctuations in the amount of electric power supplied) such as a lamp and a defogger. The capacity is larger than that of the sub battery 18. The main battery 16 is provided with a voltage sensor 28 for detecting the battery voltage, and the detection signal is output to the ECU 20.

  Unlike the main battery 16, the sub-battery 18 is driven by a small amount of electric power but is not allowed to change the supply amount. . However, the sub battery 18 is configured to supply power to the starter 14 via the primary relay 22 and the secondary relay 24 when determining the deterioration of the sub battery 18 as will be described later. The sub-battery 18 is also provided with a voltage sensor 32 for detecting the battery voltage, and the detection signal is output to the ECU 20.

  The main battery 16 and the sub battery 18 are charged by an alternator 34 driven by the engine 12 during operation of the engine 12.

  When the starter 14 rotates the crankshaft, the ECU 20 is configured to start the engine 12 by controlling a fuel injection valve, a spark plug, and the like in accordance with the rotation.

  In addition, the ECU 20 stops the engine 12 after a predetermined stop condition is satisfied, and when the predetermined start condition is satisfied after that, the ECU 20 drives the starter 14 and injects and burns fuel to restart the engine 12. That is, the engine 12 is configured to perform idle stop control (automatic stop control of the engine 12).

  Further, the ECU 20 is configured to determine deterioration of the main battery 16 and the sub battery 18 (functions as a battery deterioration detection device).

  The term “deterioration” used here is used to the extent that an electric load such as the starter 14 cannot be reliably driven (sometimes the electric load can be driven). It is confirmed that this means that the amount of power that can be supplied even after charging is not restored to the maximum amount, and that it cannot never supply power.

  As shown in FIG. 2, the ECU 20 includes a main battery deterioration determination unit 50 that performs deterioration determination of the main battery 16 based on a signal from the voltage sensor 28 and a voltage sensor 32 in order to function as a battery deterioration detection device. A sub-battery deterioration determination unit 52 that determines the deterioration of the sub-battery 18 based on the signal of the primary battery 22, a primary relay control unit 54 that controls the primary relay 22, a secondary relay control unit 56 that controls the secondary relay 24, and the main battery 16 And / or a battery deterioration notification unit 58 that notifies the driver of the deterioration of the sub-battery 18. An idle stop prohibition determination unit 60 that determines prohibition of idle stop based on the deterioration determination results of the main battery 16 and the sub battery 18 is provided.

  From here, the details of the ECU 20, in particular, the content of the control in which the ECU 20 functions as a battery deterioration detection device to detect battery deterioration and determines whether or not idle stop is prohibited based on the detection result. To do.

  The deterioration determination of the main battery 16 and the sub battery 18 is performed when the ignition key switch 36 is turned on. Specifically, the flow of control performed by the ECU 20 is shown. Specifically, whether or not the idle stop is executed in the operation of the vehicle after the ignition key switch 36 is turned on based on the deterioration determination result of the main battery 16 and the sub battery 18. This will be described with reference to the flow shown in FIG.

  First, as a premise, before the ignition key switch 36 is turned ON, the primary relay 22 and the secondary relay 24 are in the OFF state (see FIG. 1).

  As shown in FIG. 3, in the first step 100, the ignition key switch 36 is turned ON.

  In the next step 110, it is determined by the temperature sensor 38 whether or not the engine temperature of the engine 12 is equal to or higher than a predetermined temperature. By looking at the engine temperature, the temperature of the primary relay 22 is indirectly seen. This is because the primary relay 22 is brought into a connected state in the next step 120, whereby a large current flows from the sub battery 18 to the starter 14, and at this time, if the temperature of the primary relay 22 is too low, the primary relay 22 may be damaged. Yes, to prevent it. When the engine temperature is equal to or higher than the predetermined temperature, the routine proceeds to step 120 where the primary relay 22 is connected. Otherwise, go to step 130.

  In step 120, the primary relay 120 is connected. This is for determining the deterioration of the sub-battery 18 as will be described later.

  In step 130, the starter 14 is powered and driven. At this time, if the primary relay 22 is in the connected state in step 120, the starter 14 is driven by receiving power supply from the main battery 16 and the sub battery 18. When primary relay 22 is in an unconnected state (when step 120 is not executed), starter 14 is driven by receiving power supply from main battery 16 only.

  In step 140, in synchronization with the starter 14 drive, the ECU 20 controls the fuel injection valve, the spark plug, and the like to start the engine 12.

  In step 150, at least one of the main battery 16 or the sub battery 18 is determined to be deteriorated by the respective deterioration determining units 50 and 52.

  When the primary relay 22 is in a connected state (when the process of step 120 is executed), that is, when the starter 14 is driven by receiving power supply from the main battery 16 and the sub-battery 18, the deterioration determination of both batteries is performed. On the other hand, when the primary relay 22 is not connected (when the process of step 120 is not executed), that is, when the starter 14 is driven by receiving power supply only from the main battery 16, the deterioration determination of only the main battery 16 is performed. Is called.

  The method for determining the deterioration of the battery is the same for both the main battery and the sub battery. The deterioration determination of the main battery 16 will be described as an example.

  As shown in FIG. 4, when the main battery 16 starts to supply power to an electric load (starter 14 in the present invention) that requires a large amount of power to drive, the battery voltage rapidly decreases and is specified over time. The behavior of recovering to the voltage value of is shown. The battery voltage decrease behavior (the degree of decrease) is greater when the battery is degraded than when it is normal without degradation.

  Therefore, it is possible to determine the deterioration of the main battery based on the battery voltage decrease behavior of the main battery 16 that occurs when the power supply to the starter 14 is started. For example, when a predetermined value is set as shown in FIG. 4 and the battery voltage value that has decreased due to the start of power supply to the starter 14 is greater than or equal to the predetermined value, the battery is determined to be normal; It is possible to determine.

  Returning to FIG. 3, when the primary relay 22 is in the connected state and at least one of the main battery 16 or the sub battery 18 is determined to be deteriorated in step 150, or the primary relay 22 is in the unconnected state and the main battery 16 is disconnected. If the deterioration is determined, the process proceeds to step 160. Otherwise, go to step 190.

  In step 160, the battery deterioration notification unit 58 notifies the user of the battery deterioration. For example, an instrument panel battery lamp is turned on.

  Next, at step 170, the idle stop prohibition determination unit 60 prohibits the idle stop after the ignition key 36 is turned on. Thereby, the prohibition of idle stop is maintained until the ignition key 36 is turned off.

  In step 180, when primary relay 22 is in a connected state (when primary relay 22 is in a connected state in step 120), primary relay 22 is turned off. This is because the deterioration determination of the sub battery 18 is completed. Then, the flow ends.

  On the other hand, if it is determined in step 150 that neither the main battery 16 nor the sub-battery 18 is deteriorated, in step 190, the idle stop prohibition determination unit 60 determines not to prohibit idle stop. Then, the process proceeds to Step 180.

  FIG. 5 shows the relationship between the deterioration determination result of the main battery 16 and the sub battery 18 and the idle stop according to the flow of FIG. In the figure, “undecided” refers to the case where the process of step 120 is not executed in the control of the flow of FIG. 3. As shown in FIG. 5, the idle stop is executed when it is clear that the main battery 16 is normal when the ignition key 36 is ON and the sub battery 18 is not deteriorated.

  In addition, when the sub battery 18 is charged while the vehicle is running, the ECU 20 maintains the primary relay 22 unconnected and the secondary relay 24 in the connected state in principle. This is because the sub-battery 18 is charged by the alternator 34. Thereby, the sub-battery 18 can continue to supply power to the second electric load 30.

  If the sub battery 18 is determined to be deteriorated (or not yet determined) when the ignition key 36 is ON, when the sub battery 18 is charged, the primary relay 22 is temporarily turned on before the secondary relay 24 is connected. For a short time. This is performed until the potentials of the main battery 16 and the sub battery 18 are equal (if the secondary relay 24 is connected when the main battery 16 and the deteriorated sub battery 18 are not at the same potential, the secondary relay 24 may be damaged). Because there is.)

  Further, when it is clear that the main battery 16 is normal and the sub-battery 18 is not deteriorated when the ignition key 36 is turned on, the ECU 20 stops the vehicle after a predetermined automatic stop condition is satisfied. The idle engine 12 is stopped. At this time, when the secondary relay 24 is in a connected state (when the sub battery 18 is being charged), the ECU 20 is not connected.

  The ECU 20 determines the deterioration of the battery even when the engine 12 is restarted after the idle stop, as in the case where the ignition key 36 is ON. However, only the main battery 16 is performed. This is because it is assumed that the main battery 16 is deteriorated during traveling.

  The reason why the deterioration determination of the sub battery 18 is not performed when the engine 12 is restarted, that is, the reason why the sub battery 18 and the starter 14 are not connected via the primary relay 22 as in the case where the ignition key 36 is ON will be described.

  At the timing of restart of the engine 12 after the idle stop, the sub battery 18 continues to supply power to the second electric load. Here, if the sub battery 18 is connected via the primary relay 22 to the starter 14 that assists the restart of the engine 12 for the deterioration determination, there is a possibility that a shortage of power supply to the second electric load may occur. There is a possibility that the operation of the second electric load becomes unstable or worst stops. For example, the navigation system supplied with power from the sub battery 18 may stop. Therefore, the deterioration determination of the sub battery 18 cannot be performed when the engine 12 is restarted after the idle stop. In other words, the timing at which the deterioration determination of the sub-battery 18 can be performed is only when the ignition key 36 is ON, when the second electric load is not driven.

  The starter 14 is driven to assist in restarting the engine 12, but it is run solely from the main battery 16. At this time, the main battery deterioration determination unit 50 determines deterioration of the main battery 16 based on a decrease in battery voltage that occurs when power supply to the starter 14 is started.

  If the main battery 16 is normal as a result of the deterioration determination, the idle stop prohibition determination unit 60 permits the next idle stop without prohibiting it. On the other hand, when the deterioration is determined, the next idle stop is prohibited.

  The starter 14 may be driven even if the main battery 16 is determined to be deteriorated, but the starter 14 may not be driven only by the main battery 16 determined to be deteriorated. In this case, the sub battery 18 is used as emergency means. That is, the primary relay 22 is connected, and the deteriorated main battery 16 and sub battery 18 cooperate to drive the starter 14. Then, immediately after the engine 12 is restarted, the primary relay 22 is disconnected.

  According to the present embodiment, when the ignition key switch 36 is turned on, the starter 14 is driven by the main battery 16 and the sub battery 18. At this time, the deterioration determination of the main battery 16 and the sub-battery 18 is executed based on the lowering behavior of each battery voltage that occurs when the main battery 16 and the sub-battery 18 start to supply power to the starter 14. The Therefore, when the ignition key switch 36 is turned on, the starter can be driven by the cooperation of the main battery 16 and the sub battery 18 even if the main battery 16 is deteriorated. Battery deterioration can also be detected. In this embodiment, as described above, the sub-battery is a battery that cannot continue to supply power to an electric load that is not allowed to change the amount of power supplied after the ignition key switch is turned on and cannot perform deterioration determination after the ignition key switch is turned on. Useful in some cases.

  The present invention has been described above by taking one embodiment as an example, but the present invention is not limited to this.

  For example, in the above-described embodiment, when the engine that has been idle-stopped restarts, the deterioration determination of the sub-battery cannot be performed. This is because the above-described sub-battery is a battery that continues to supply power to an electric load that is not allowed to decrease the amount of supplied power when the engine is restarted. On the other hand, if the sub-battery supplies power to an electric load that allows fluctuations in the amount of power supplied when the engine is restarted, it is connected to a starter as described above to determine deterioration. Is possible. In this case, the determination result of the sub-battery can be taken into consideration in determining whether to prohibit the next idle stop.

It is a schematic block diagram of the control apparatus of the engine which detects deterioration of the battery which concerns on one Embodiment of this invention. It is a block diagram in ECU functioning as a battery deterioration detection apparatus. FIG. 5 is a control flow diagram from detection of battery deterioration to determination of prohibition of idle stop. It is a figure for demonstrating the deterioration detection method of a battery. It is a figure which shows the relationship between the deterioration determination result of the battery derived | led-out by the flow of FIG. 3, and the idle stop for which prohibition determination is carried out based on the result.

Explanation of symbols

14: Starter 16: Main battery 18: Sub battery 22: Relay (primary relay)
26: First electric load 30: Second electric load 36: Ignition key switch

Claims (4)

A battery deterioration detection device that detects battery deterioration in a vehicle having a first battery that supplies power to a first electric load and a starter, and a sub-battery that supplies power to a second electric load,
A relay connecting the sub-battery and the starter;
Relay control means for connecting the starter and the sub-battery via the relay when an ignition key switch is turned ON;
Based on the battery voltage drop behavior that occurs when the sub-battery and the main battery connected to the starter via the relay by the relay control means start supplying power to the starter, respectively. A battery deterioration detection device comprising a battery and battery deterioration determination means for determining deterioration of the sub-battery. The battery deterioration detection device according to claim 1,
Having engine temperature detecting means for detecting the temperature of the engine;
The relay control unit is configured not to connect the starter and the sub-battery via the relay when the temperature detected by the engine temperature detection unit is equal to or lower than a predetermined temperature. Deterioration detection device. The battery deterioration detection device according to claim 1 or 2,
A battery deterioration detection device comprising deterioration notification means for notifying a user of battery deterioration when the battery deterioration determination means detects deterioration of at least one of the main battery or the sub battery. In the battery deterioration detection device according to any one of claims 1 to 3,
Automatic stop control means for automatically stopping the engine when a predetermined engine stop condition is satisfied, and automatically starting the engine when a predetermined engine start condition is satisfied during the stop;
The battery deterioration detection device, wherein the automatic stop control means is configured to prohibit automatic engine stop when the battery deterioration determination means detects battery deterioration.

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