JP2016097729A - Battery monitoring device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To properly determine that starting of an engine is performed by jump start or is performed with electric power supply from a newly replaced battery.SOLUTION: A battery monitoring device 15 comprises: an acquisition means, in starting an engine 10, acquiring a predetermined characteristic value showing the characteristics of a battery 11 when electric power is supplied from the battery 11 to a starter 12; a prediction means calculating a prediction value VA of the characteristic value in starting at this time on the basis of the characteristic value acquired in starting of the engine 10 before the previous time; and a determination means determining, when starting of the engine 10, on the basis of a difference between the characteristic value acquired at this time and the prediction value VA calculated by the prediction means, that starting at this time is performed by jump start or is performed with electric power supply from a newly replaced battery 11.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a battery monitoring device that monitors a battery when an engine is started.

  Since the in-vehicle battery deteriorates with long-term use, a jump start in which power is supplied from the rescue vehicle and a new battery replacement are performed as necessary. In such a case, when starting the engine, the battery voltage change amount (or its correlation value) at the time of power supply to the starter is detected as a characteristic value indicating the battery characteristics, and the engine start is performed based on the battery voltage change amount. There is a technique for determining whether it is due to a jump start or due to power supply from a newly replaced battery.

  Further, for example, in the device described in Patent Document 1, it is determined that it is a jump start when the voltage drop width of the battery is equal to or greater than a predetermined threshold at the time of engine start. Specifically, a threshold value is set between the voltage drop width at the normal start time not at the jump start time and the voltage drop width at the jump start time, and the jump start determination is performed using this threshold value.

JP 2001-107768 A

  However, the characteristic value of the battery at the time of supplying power to the starter varies depending on the vehicle due to individual differences, usage conditions, and the like, and the characteristic value may be different for each battery even in a battery deterioration state that requires battery replacement. it is conceivable that. Therefore, there is a concern that an erroneous determination may occur when the jump start determination is performed based on the characteristic value acquired when the engine is started. In other words, since the characteristic value at the time of jump start depends on the characteristic value at the time of engine start (previous start) immediately before the jump start, the characteristic value at the previous start varies for each battery (for each vehicle). As a result, there is a concern that a jump start judgment failure may occur.

  For example, in a vehicle that performs idling stop control, automatic engine stop is prohibited during vehicle operation after jump start. However, if a jump start detection failure occurs, there is a concern about influence on idling stop control.

  Further, even when the battery is replaced with a new battery, the characteristic values of the battery before and after the replacement include variations for each vehicle due to individual differences and usage conditions. Therefore, if it is assumed that the tendency of the characteristic value after replacement of a new product varies from vehicle to vehicle, there is a concern that erroneous determination of a new battery may result.

  The present invention has been made to solve the above-mentioned problem, and appropriately determines whether the engine is started by jump start or by power supply from a battery that has been replaced with a new one. The object is to provide a battery monitoring device capable of performing

  Hereinafter, means for solving the above-described problems, and actions and effects thereof will be described.

  The battery monitoring device of the present invention is based on an acquisition means for acquiring a predetermined characteristic value indicating a characteristic of the battery when power is supplied from the battery to the starter, and a characteristic value acquired at the previous start of the engine. Thus, the current start jumps based on the prediction means for calculating the predicted value of the characteristic value at the time of the current start and the difference between the characteristic value acquired this time and the predicted value calculated by the prediction means at the time of engine start. And determining means for determining whether it is due to start or due to power supply from a newly replaced battery.

  When the jump start is performed, the engine is started with power supplied from the rescue vehicle in addition to the power supplied from the host vehicle. Therefore, the starter is compared with the engine start immediately before the jump start (previous start). The characteristic value at the time of power supply to (for example, the minimum voltage value immediately after the start of power supply) changes. Here, the characteristic value at the time of starting the engine differs for each vehicle due to individual differences, usage conditions, etc., and the characteristic value at the time of jump start depends on the characteristic value at the time of previous start. In this case, for example, if the minimum voltage value at the time of the previous start is relatively small, the minimum voltage value at the time of jump start decreases accordingly. Occurs.

  In this regard, in the above configuration, since the predicted value of the current characteristic value is calculated based on the characteristic value acquired at the start before the previous time and the jump start determination is performed using the predicted value, the characteristic immediately before the jump start is calculated. Even if the value is different for each vehicle, it is possible to suppress erroneous determination of jump start due to the value. Therefore, the jump start determination accuracy can be increased.

  When the battery is replaced with a new one for the same vehicle, the tendency of the characteristic value (minimum voltage value) when power is supplied to the starter is the same between the old battery before replacement and the new battery after replacement. Therefore, it is possible to improve the determination accuracy by calculating the predicted value of the current characteristic value based on the characteristic value acquired at the start before the previous time and determining the replacement of the new battery using the predicted value.

The block diagram which shows schematic structure of the vehicle system concerning this embodiment. The time chart which shows the voltage fluctuation of the battery by engine starting. The figure which shows the relationship between the minimum voltage value Ve of a battery, and the frequency | count of start-up. The flowchart which shows the process sequence which determines jump start and new battery replacement. The flowchart which shows the process sequence for calculating an approximate line.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments embodying the present invention will be described below with reference to the drawings. The present embodiment embodies a vehicle equipped with an engine, and uses an electronic control unit (hereinafter referred to as ECU) to perform various controls of the engine. FIG. 1 shows the overall configuration of the engine system in the present embodiment.

  As shown in FIG. 1, the engine 10 is provided with a starter 12 as a starting device that applies an initial rotation (cranking rotation) of the engine 10 when the engine is started. An alternator 13 is connected to the crankshaft of the engine 10 via connecting means such as a belt. The alternator 13 is connected to a battery 11 and an electric load 14 such as a headlight or an audio device. An electric load 14 is connected to the battery 11 via an ignition switch 16.

  The starter 12 is connected to the battery 11 via a relay 22 and an ignition switch 16. The starter 12 is driven at the time of manual start by the driver's ignition key operation and at the time of automatic restart by execution of the idling stop control. In the case of manual start by the driver, when the ignition key reaches the start position, the start switch of the ignition switch 16 is closed and the relay 22 is energized. As a result, the relay circuit of the battery 11 and the starter 12 is closed, and power is supplied from the battery 11 to the starter 12. The starter 12 is driven by power supply and starts the engine 10. Further, when the engine 10 is automatically restarted by executing the idling stop control, the relay 22 is controlled by an idling stop ECU 18 described later when a predetermined condition is satisfied. As a result, the relay circuit between the battery 11 and the starter 12 is closed, and the starter 12 starts the engine 10.

  The alternator 13 is connected to the crankshaft of the engine 10 via connecting means such as a belt, and is driven to generate electric power as the engine 10 rotates. The generated power is supplied to the battery 11 and the electric load 14.

  The electrical load 14 receives power supply from the alternator 13 and the battery 11. Specifically, when the ignition key is moved to the ACC position by the driver's operation, the ACC switch of the ignition switch 16 is closed. Accordingly, the relay circuit between the battery 11 and the electric load 14 is closed, and electric power is supplied from the battery 11 to the electric load 14. Further, during the automatic engine stop by the execution of the idling stop control, the relay 22 is controlled by the idling stop ECU 18, and the relay 22 between the battery 11 and the electric load 14 is closed. Then, electric power is supplied from the battery 11 to the electric load 14.

  As the battery 11, for example, a 12V lead storage battery is employed. The battery 11 supplies power to the starter 12 and the electrical load 14 as described above, and also supplies power to the engine ECU 15 and the idling stop ECU 18. The battery 11 includes a voltage sensor 17 that measures the voltage of the battery 11.

  This engine system detects both the ECU (electronic control unit) of the engine ECU 15 and the idling stop ECU 18, a vehicle speed sensor 19 for detecting the vehicle speed, an accelerator sensor 20 for detecting the depression amount of the accelerator pedal, and a depression amount of the brake pedal. Various sensors such as a brake sensor 21 are provided. These various sensors are connected to the engine ECU 15, and signals from the various sensors are sequentially input to the engine ECU 15. Each ECU is mainly composed of a microcomputer including a central processing unit (CPU) and a storage device (ROM and RAM), and executes various programs stored in the ROM. Each ECU receives and activates a signal when the ignition key reaches the IG position by the driver's operation, and operates with electric power supplied from the battery 11. Further, the detection value detected by the voltage sensor 17 is taken into the engine ECU 15 and then transmitted to the idling stop ECU 18. The engine ECU 15 and the idling stop ECU 18 can communicate with each other bidirectionally.

  The engine ECU 15 transmits a signal for driving the fuel injection system and the ignition system to the engine 10 based on the request for engine operation and the engine operation state. Further, the engine ECU 15 controls the power generation amount of the alternator 13 based on, for example, the voltage of the battery 11 and the remaining capacity (SOC). The remaining capacity (SOC) of the battery 11 may be calculated from the battery voltage and the charge / discharge current as is well known. In addition to the above, the engine ECU 15 has a start determination function for determining whether the start of the engine 10 is due to a jump start or power supply from the battery 11 that has been replaced with a new one. Yes. The details will be described later.

  The idling stop ECU 18 inputs the vehicle speed acquired by the engine ECU 15, the amount of depression of the accelerator pedal, the amount of depression of the brake pedal, and the voltage of the battery 11, and performs idling stop control based on these information.

  Next, details of the start determination function will be described. In this embodiment, the minimum voltage value Ve after the start of power supply to the starter 12 is used as the characteristic value of the battery 11 when power is supplied to the starter 12, and the engine 10 is started based on the minimum voltage value Ve. A determination is made as to whether it is due to a jump start or due to power supply from a newly replaced battery 11.

  FIG. 2 shows the voltage fluctuation of the battery 11 when the engine 10 is started. Note that when the engine 10 is started, power generation by the alternator 13 is stopped, and power generation by the alternator 13 is started when the engine 10 is started. The period without the first voltage fluctuation is a stop period of the engine 10. When energization of the starter 12 is started, no induced voltage is generated in the starter 12, so that a large current (inrush current) flows through the starter 12. As a result, the voltage of the battery 11 is greatly reduced, and a minimum voltage value Ve, which is the minimum value of the voltage of the battery 11, is generated. When the starter 12 starts rotating, the current flowing through the starter 12 decreases, and the voltage of the battery 11 increases.

  Further, in this embodiment, in order to improve the accuracy of the jump start determination and the new battery determination, the minimum at the current start is determined based on the temporal changes of the plurality of minimum voltage values Ve acquired at the previous start of the engine 10. A predicted value of the voltage value Ve is calculated, and each of the above determinations is performed using the predicted value. That is, it is considered that the minimum voltage value Ve of the battery 11 is different for each vehicle depending on individual differences, usage conditions, etc., and changes at a certain degree over a long period immediately before jump start or immediately before replacement of the battery 11 with a new one. For example, in terms of the environment outside the vehicle, the minimum voltage value Ve tends to be generally high in the case of a vehicle used in a high temperature environment, and the minimum in the case of a vehicle used in a low temperature environment. It is considered that the voltage value Ve tends to decrease as a whole. Therefore, in the host vehicle, the jump start or new battery replacement is determined in consideration of the tendency of the minimum voltage value Ve.

  Specifically, the engine ECU 15 acquires the minimum voltage value Ve measured every time the engine 10 is manually started, and stores the minimum voltage value Ve in a memory in the ECU in time series. Further, by linearly approximating the measured values of the plurality of time series minimum voltage values Ve, a linear function (approximation function) using the number of starting times from when the battery is new and the minimum voltage value Ve as variables is calculated. A predicted value of the minimum voltage value Ve is calculated each time the engine 10 is manually started using a linear function. Then, based on the difference between the measured value of the minimum voltage value Ve and the predicted value, jump start determination and new battery determination are performed.

  A supplementary explanation will be given with reference to FIG. In FIG. 3, the horizontal axis represents the number of start times, the vertical axis represents the minimum voltage value Ve, and the measured value of the minimum voltage value Ve is indicated by a cross. In this case, the approximate line L1 is calculated by linearly approximating a plurality of time series measurement values. The approximate line L1 may be calculated using a newly acquired measurement value each time a predetermined update condition is satisfied, and the approximate line L1 so far may be updated with the new approximate line L1. For example, the update condition may be that the cumulative number of manual starts from the previous start is a predetermined number, or that the cumulative time of vehicle operation is a predetermined time.

  For example, when the current start count is P, the predicted value of the current minimum voltage value Ve is calculated as VA from the approximate line L1. Further, at the time of jump start, since power is supplied from the rescue vehicle, the minimum voltage value Ve of the battery 11 becomes a relatively large value, for example, VB in FIG. In this case, it is possible to determine that the current start is a jump start based on the difference between the predicted value VA of the minimum voltage value Ve and the measured value VB.

  Similarly, at the time of replacement of a new battery, the minimum voltage value Ve of the battery 11 becomes a relatively large value (for example, VB in FIG. 3). In this case, based on the difference between the predicted value VA of the minimum voltage value Ve and the measured value VB, it can be determined that the current start is due to a new battery.

At the time of jump start and battery replacement, the measured value VB becomes larger than the predicted value VA of the minimum voltage value Ve.
VB−VA ≧ Vth (1)
Is established. Vth is a threshold set based on the distribution (degree of variation) of a plurality of minimum voltage values Ve stored in time series. Note that the threshold value Vth may be determined based on the amount of auxiliary power supplied from the rescue vehicle or an increased voltage determined in consideration of the voltage difference between the deteriorated battery and the new battery.

  In this case, whether the jump start or the battery is replaced is determined based on the number of times the above expression (1) is continuously established when the engine 10 is manually started. Specifically, when the above formula (1) is established only once at the time of manual start of the engine 10, it is determined that the jump start is established, and the above formula (1) is established two or more predetermined times. If it is continuous, it is determined that the battery is being replaced. Note that the number of times the above expression (1) is established is stored in a memory, and it is determined whether the above expression (1) is established only once or continuously two or more times.

  Next, the detailed procedure of the process performed by the engine ECU 15 will be described with reference to FIG. This process is repeatedly performed by the engine ECU 15 at a predetermined cycle.

  In FIG. 4, in step S11, it is determined whether or not the engine 10 is being manually started. If it is not at the time of engine start, this processing is terminated, and if it is at the time of engine start, the process proceeds to step S12.

  In step S12, the lowest voltage value Ve measured by the voltage sensor 17 is acquired as the measured value VB. At this time, the measured value VB is stored in the memory in association with the current start count (accumulated count since the battery is new). In step S13, the estimated value VA of the lowest voltage value Ve at the time of the current engine start is calculated using the approximate line L1 calculated from the past measurement value VB. In step S14, the threshold value Vth is calculated based on the distribution of a plurality of time-series measured values VB (including the current value). At this time, the threshold value Vth is increased as the degree of variation increases.

  Thereafter, in step S15, it is determined whether or not the difference (VB−VA) between the measured value VB of the minimum voltage value Ve and the predicted value VA is equal to or greater than the threshold value Vth. If step S15 is YES, the process proceeds to step S16. If NO, the process proceeds to step S19.

  In step S16, it is determined whether or not the engine start in which step S15 is YES has continued twice or more. If step S15 is YES only once, it is determined that the current start is a jump start (step S17). In this case, the engine ECU 15 instructs the idling stop ECU 18 to prohibit the automatic engine stop of the idling stop control during the current vehicle travel. Further, when the vehicle is traveling this time, the adjustment voltage of the alternator 13 is set higher than usual to promote power generation, or the power consumption by the electric load 14 is limited.

  If step S15 becomes YES twice or more, it is determined that the current start is due to replacement of a new battery 11 (step S18). In this case, the engine ECU 15 deletes the history data of the lowest voltage value Ve so far. When it is determined that the battery is a new battery, the engine is not automatically stopped by idling stop control, the power generation of the alternator 13 is promoted, and the power consumption is not limited by the electric load 14.

  In step S19, the approximate line L1 is calculated. This will be described with reference to the subroutine of FIG. In FIG. 5, in step S21, it is determined whether or not an update condition for updating the approximate line L1 is satisfied. As described above, the update condition may be determined based on the cumulative number of manual startings, the cumulative time of vehicle operation, and the like. However, the approximate line L1 may be updated every time the engine is manually started.

  In a succeeding step S22, it is determined whether various conditions such as a temperature environment regarding the battery 11 are satisfied. Specifically, the temperature environment data of the battery 11 such as the battery temperature, the engine water temperature, and the outside air temperature, and the remaining battery capacity (SOC) are used as parameters, and these are within a predetermined range, and the minimum voltage value Ve It is determined that the fluctuation factor is not large. And when each condition of step S21, S22 is materialized, it progresses to step S23.

  In step S23, an approximate line L1 composed of a linear function is calculated based on the current and past measurement values VB acquired under the conditions in which steps S21 and S22 are both YES. At this time, by referring to a plurality of time-series measured values VB (including the current value) and the number of times of starting at the time of measuring each measured value VB, an approximate line using the number of times of starting and the minimum voltage value Ve as variables. L1 is calculated.

  According to the embodiment described in detail above, the following excellent effects can be obtained.

  The current predicted value VA is calculated based on the lowest voltage value Ve acquired at the start before the previous time, and the jump start determination or the new article replacement determination is performed using the predicted value VA. Even if Ve is different for each vehicle, an erroneous determination of jump start due to the Ve can be suppressed. Therefore, the jump start determination accuracy can be increased. Further, when the battery 11 is replaced with a new one for the same vehicle, the tendency of the minimum voltage value Ve when power is supplied to the starter 12 is the same between the old battery before replacement and the new battery after replacement. Therefore, it is possible to improve the determination accuracy by calculating the current predicted value VA based on the lowest voltage value Ve acquired at the start before the previous time and determining the replacement of the new battery using the predicted value VA. .

  An approximate line L1 is calculated based on the minimum voltage value Ve acquired in a state where predetermined conditions using the battery temperature, the engine water temperature, the outside air temperature, and the remaining battery capacity (SOC) as parameters are established, and the approximate line L1 Thus, the predicted value VA of the minimum voltage value Ve is calculated. As a result, it is possible to eliminate a disturbance factor in predicting the minimum voltage value Ve, and to improve the accuracy of the predicted value VA.

  Using the time-series minimum voltage value Ve acquired at the actual engine start, an approximate function indicating the change over time is calculated, and using the approximate function, an estimated value VA of the minimum voltage value Ve at the current start is calculated. Since the calculation is performed, the predicted value VA can be obtained with high accuracy, and the reliability of the jump start determination and the new article replacement determination can be improved.

  The minimum voltage value Ve acquired each time the engine is started has some variation. In such a case, by setting the threshold value Vth in consideration of the variation in the minimum voltage value Ve, it is possible to properly distinguish whether or not the measured value VB is a value in the variation range at the time of normal engine start. It becomes like this. Therefore, the accuracy of jump start determination and new battery determination can be improved.

  When the engine is started with the battery 11 replaced with a new one, it is considered that the minimum voltage value Ve of the battery 11 every time the engine is started becomes a high value continuously several times after the replacement of the battery 11 with a new one. It is done. In this regard, when it is determined that the start of the engine 10 is due to a jump start or the power supply from the battery 11 replaced with a new one is a plurality of times, the engine 10 In this configuration, it is determined that the starting is not based on the jump start but based on the power supply from the battery 11 that has been replaced with a new one. For this reason, it is possible to appropriately determine whether the engine 10 is started by jump start or by power supply from the battery 11 replaced with a new one.

  Since the predicted value VA of the lowest voltage value Ve is calculated based on a plurality of measured values VB in the host vehicle, it is not necessary to previously set the threshold value Vth for performing the jump start determination by conformance or the like. For this reason, it is possible to reduce the man-hours required for vehicle manufacture.

(Other embodiments)
The above embodiment may be modified as follows, for example.

  The engine 10 is configured to determine whether the start of the engine 10 is due to a jump start or the power supply from the battery 11 that has been replaced with a new one. It is good also as a structure which determines only the thing by power supply from the battery 11 replaced with the new article, or the structure which determines only by what.

  In addition to the minimum voltage value Ve measured when the engine 10 is manually started, a value measured when the engine 10 is automatically restarted by the idling stop control may be used.

  In the above embodiment, a linear function using the number of start times and the minimum voltage value Ve as variables is calculated as an approximate function used for calculating the predicted value VA. However, this may be changed. For example, a linear function having the cumulative time of vehicle operation and the minimum voltage value Ve as variables and a linear function having the vehicle travel distance and minimum voltage value Ve as variables may be calculated.

  -Although it was set as the structure which performs jump start determination using the estimated value VA as the characteristic value of the battery 11 for the minimum voltage value Ve, you may change this. For example, the jump start determination may be performed using any one of the voltage drop width of the battery 11, the internal resistance, the cranking current, the cranking frequency, the cranking pulsation cycle, the cranking torque, and the like as the characteristic value of the battery 11. .

  A linear function is calculated by approximating the lowest voltage value Ve stored in time series, but this is changed and a function of second order or higher is calculated by approximating the lowest voltage value Ve stored in time series. It is good also as a structure.

  In the above-described embodiment, the approximate line L1 is calculated using a plurality of measurement values VB acquired in time series from when the battery is new. The approximate line L1 may be calculated using the measured value VB. Moreover, the structure which calculates an approximate function may not be sufficient. In any case, any prediction value VA may be used as long as the predicted value VA is calculated based on a change with time of the plurality of measurement values VB acquired when the engine 10 was started before the previous time.

  Instead of the configuration for calculating the predicted value VA using the approximate line L1, a configuration may be used in which the measured value VB at the previous start before the jump start is calculated as the predicted value VA. Or the structure which calculates the average value of several measured value VB at the time of the start before a jump start as the predicted value VA may be sufficient.

DESCRIPTION OF SYMBOLS 10 ... Engine, 11 ... Battery, 12 ... Starter, 15 ... ECU (Acquisition means, prediction means, determination means, function calculation means, threshold setting means, count means)

Claims (6)

A battery monitoring device (15) applied to a vehicle including a starter (12) for starting an engine (10) and a battery (11) for supplying electric power to the starter,
An acquisition means for acquiring a predetermined characteristic value indicating a characteristic of the battery when power is supplied from the battery to the starter when starting the engine;
Prediction means for calculating a predicted value of the characteristic value at the current start based on the characteristic value acquired at the previous start of the engine;
When starting the engine, based on the difference between the characteristic value acquired this time and the predicted value calculated by the prediction means, the current start is due to a jump start, or from a newly replaced battery. Determination means for determining that the power supply is due to power supply;
A battery monitoring device comprising:   The prediction means sets the characteristic value acquired by the acquisition means in a state where a predetermined condition regarding at least one of the engine temperature environment, the starter temperature environment, the battery temperature environment, and the remaining capacity is satisfied. The battery monitoring device according to claim 1, wherein the prediction value is calculated based on the prediction value.   3. The battery monitoring device according to claim 1, wherein the prediction unit calculates the prediction value based on a change with time of a plurality of the characteristic values acquired at the previous start of the engine. A plurality of the characteristic values acquired at the time of starting the engine are stored in time series, and from the plurality of characteristic values, a function calculating unit that calculates an approximate function indicating a change with time of the characteristic values is provided.
The battery monitoring apparatus according to claim 1, wherein the prediction unit calculates the prediction value using the approximate function. The determination means determines that it is a jump start when the difference between the characteristic value acquired this time and the prediction value calculated by the prediction means is equal to or greater than a predetermined threshold value, or a new battery replacement. And carry out the judgment of
5. The battery monitoring device according to claim 1, further comprising a threshold setting unit configured to set the threshold based on a distribution of the plurality of characteristic values acquired in time series. The counting means includes a counting means for counting the number of times that the engine is continuously determined to start from a jump start or from a power supply from a newly replaced battery,
The determination means determines that the engine is started not by a jump start but by power supply from a newly-replaced battery when the number of times by the counting means is a predetermined number of times or more. The battery monitoring apparatus according to any one of claims 1 to 5.

Images