Vehicle control device

Abstract

To control charging / discharging of a battery on the basis of an estimated value of a battery state with high precision by preventing the estimated value from significantly deviating from a true value.SOLUTION: In a case where an EFI-ECU 4 derives a current estimated battery temperature value concerning the state of a battery 1 on the basis of an output from a sensor 2 by using a past estimated battery temperature value while setting a preset initial value as a start point, when a detected temperature value of the battery 1 obtained by the sensor 2 falls within a prescribed range (-30 to 150°C), the EFI-ECU 4 derives the current estimated battery temperature value on the basis of the detected battery temperature value in place of the preset initial value which is 200°C, for example.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a vehicle control device that controls a vehicle by estimating status data values ​​relating to the status of a battery, such as battery fluid temperature. [Background technology]

[0002] When controlling the charging and discharging of a battery installed in a vehicle, the charging and discharging of the battery is controlled so that the battery's charging voltage is optimized according to the battery's liquid temperature. However, because the electrolyte in batteries such as lead-acid batteries is highly acidic, it is not possible to provide a sensor that directly detects the battery's liquid temperature, and so the battery's liquid temperature is usually estimated using a temperature detection sensor placed near the battery (see Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2018-156808 Summary of the Invention [Problem to be solved by the invention]

[0004] Conventionally, a method for estimating the battery fluid temperature is to detect the ambient temperature of the battery using a sensor placed near the battery and smooth the detected temperature using a moving average. Specifically, the temperature detected by the sensor is THB, and the current estimated battery temperature is THBSM. n , and the past battery temperature estimates are calculated by THBSM n-1 Then, THBSM n =THBSM n-1 +G×(THB-THBSM n-1 ) The current battery temperature estimate can be calculated by the above calculation. Note that G is a predetermined value and is a gain. Here, an unusually large value such as 200°C is set as the initial value of THB.

[0005] However, because the temperature value detected by the sensor is affected by engine heat and outside air temperature, it is easy for a discrepancy to occur between the actual battery fluid temperature and the estimated value. If battery charging and discharging control is performed based on a discrepant battery temperature estimate, it is not possible to accurately control battery charging and discharging, and inappropriate battery charging and discharging control may result in a deterioration in fuel efficiency.

[0006] Furthermore, when the temperature detected by the sensor is transmitted to the calculation means via communication, even when the ignition switch is turned on, there is a time delay before the ECU (Electronic Control Unit), which constitutes the means involved in communication, wakes up from a sleep state and becomes capable of communication. During this time delay, a large initial value such as 200°C is used in the calculation described above, and the calculated estimated battery temperature value is influenced by the initial value, causing the estimated temperature value to deviate significantly from the true value, which again may result in the inability to accurately control the charging and discharging of the battery.

[0007] An object of the present invention is to prevent an estimated value of the state of a battery from deviating significantly from the true value, and to enable accurate control of charging and discharging of the battery based on the estimated value. [Means for solving the problem]

[0008] In order to achieve the above object, the vehicle control device of the present invention comprises an ignition Switch on a charging means for charging a battery mounted on a vehicle by the above-mentioned method; and an acquisition means for acquiring a status data value relating to the status of the battery by LIN communication; a preset initial value based on the status data value output from the acquisition means; and Regarding the state of the battery By calculating using past battery temperature estimates current Battery Temperature Estimated value Lead and a lead-out means for outputting the charge, and the charge means is Switch on The charging of the battery is started by the following, and the deriving means After the ignition switch is turned on, the LIN communication The acquisition means is output from When the status data value falls within a predetermined range, It is determined that the LIN communication has started normally, and the update flag is switched from off to on. Instead of the initial value The output from the acquisition means State data value By the above calculation as the initial value current Battery Temperature Derive an estimate, After the ignition switch is turned on, if the status data value output from the acquisition means through the LIN communication is not within the predetermined range, it is determined that the LIN communication has not started normally, and the update flag is kept off and the calculation is not performed, and the charging means By the deriving means After the update flag is turned on, The derived current Battery Temperature The charge / discharge control of the battery is started based on the estimated value. [Effects of the Invention]

[0009] According to the present invention, the ignition Switch on the charging means starts charging the battery; When the state data value output from the acquisition means by the LIN communication becomes a value within a predetermined range after the ignition switch is turned on, the derivation means determines that the LIN communication has started normally and switches the update flag from off to on, and derives a current battery temperature estimate by calculation using the state data value output from the acquisition means as a calculation initial value instead of a preset initial value, and the charging means calculates the current battery temperature estimate by the derivation means after the update flag is turned on. Derivation Based on the current battery temperature estimate To start battery charge / discharge control, As before, It is possible to prevent the initial value from being dragged down by a large value that exceeds a predetermined range. Battery Temperature Prevents the estimated value from deviating too much from the true value and makes it closer to the true value. Battery Temperature It becomes possible to derive an estimated value, and when battery charge / discharge control is performed based on the estimated battery temperature value, accurate control becomes possible. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a block diagram of an embodiment of a vehicle control device of the present invention; [Figure 2] FIG. 2 is an explanatory diagram of the operation of FIG. [Figure 3] FIG. 2 is an explanatory diagram of the operation of FIG. [Figure 4] 2 is a flowchart illustrating the operation of FIG. 1. [Figure 5] 2 is a flowchart illustrating the operation of FIG. 1. DETAILED DESCRIPTION OF THE INVENTION

[0011] An embodiment in which a vehicle control device according to the present invention is applied to a conventional vehicle that is driven only by an engine will be described in detail with reference to FIGS. 1 to 5. FIG.

[0012] As shown in Fig. 1, a current / temperature sensor (hereinafter simply referred to as "sensor") is provided in the vicinity of battery 1, which is a lead-acid battery with a nominal voltage of 12V, for detecting the battery current and battery temperature including the housing temperature, and the current and temperature values ​​detected by sensor 2 are transmitted by LIN (Local Interconnect Network) communication to EFI-ECU (EFI: Electronic Fuel Injection) 4 via a cable 3 for LIN communication, rather than by a so-called direct wire, and are received by EFI-ECU 4. Here, sensor 2 corresponds to the "acquisition means" in this invention, and the temperature value detected by sensor 2 corresponds to the "status data value" regarding the status of battery 1 in this invention.

[0013] When an ignition switch (not shown) is turned on, the starter relay is turned on, power is supplied from the battery 1 to the starter 5, and the starter 5 starts, which starts the stopped engine 6 and the alternator 7 starts generating electricity, charging the battery 1. Note that if charge / discharge control of the battery 1 is performed when the battery temperature is low, the battery 1 will deteriorate, so the battery fluid temperature is estimated after the engine 6 is started, and charge / discharge control is started when the estimated battery fluid temperature reaches, for example, 15°C.

[0014] The power generation state of the alternator 7 is acquired by the EFI-ECU 4, and a power generation voltage corresponding to the acquired power generation state is instructed to the alternator 7 by the EFI-ECU 4, and the alternator 7 generates power at the instructed power generation voltage.

[0015] In addition, the power of the battery 1 is supplied to a plurality of electric loads such as various motors for lights, power windows, electric power steering, etc. mounted on the vehicle, and a load signal according to the operating state of each electric load is input to the EFI-ECU 4.

[0016] The battery fluid temperature is detected by the EFI-ECU 4 based on the temperature value detected by the sensor 2 and is estimated by the calculation of the following equation (1). In equation (1), the temperature value detected by the sensor 2 is THB, and the current estimated battery temperature is THBSM. n , and the past battery temperature estimates are calculated by THBSM n-1 , Gain is a predetermined value, THBSM n =THBSM n-1 +Gain×(THB-THBSM n-1 ) …(1) formula The initial value THB of THB is set to an impossibly large value (abnormal value), such as 200° C. Here, the EFI-ECU 4 corresponds to the “deriving means” in the present invention.

[0017] At this time, if the temperature value of the battery 1 detected by the sensor 2 is normally transmitted by LIN communication, the EFI-ECU 4 starts the calculation of the above-mentioned formula (1), and whether the LIN communication has started normally is determined by whether the temperature value of the battery 1 detected by the sensor 2 is within a predetermined range of -30°C to 150°C (-30°C≦THB≦150°C). Note that the temperature range of -30°C to 150°C is an example, and the predetermined range is not limited to this, but it is desirable to set it to a predictable range based on the outside air temperature in the environment where the vehicle is actually used.

[0018] Specifically, as shown in FIG. 2, at time t1 after the ignition switch is turned on, when the detected temperature value THB of, for example, 20°C is detected by the sensor 2 and received by the EFI-ECU 4, since the detected temperature value THB is within a predetermined range of -30°C to 150°C, it can be determined that the ECU or the like has woken up and the initial LIN communication has started normally after the ignition switch was turned on at time t1, and an update flag provided in the built-in memory or the like of the EFI-ECU 4 is switched from off to on at time t1.

[0019] On the other hand, even if the ignition switch is turned on, if the detected temperature value THB received by the EFI-ECU 4 is not within the range of -30°C to 150°C, it is determined that LIN communication has not started normally and the update flag is kept off.

[0020] Here, if the update flag is off, that is, if the temperature value THB detected by the sensor 2 is not within the predetermined range of -30°C to 150°C, then the LIN communication has not started normally and the temperature value THB of the battery 1 detected by the sensor 2 has not been received by the EFI-ECU 4. Therefore, as shown in FIG. 2, while the update flag is off, the battery temperature estimated value THBSM is set to a predetermined initial value such as 200°C, but the calculation of equation (1) does not start while the update flag is off.

[0021] Furthermore, after the update flag is set to ON at time t1, assuming that the communication cycle of the LIN communication is 200 msec, for example, at time t2, which is the timing of the next LIN communication 200 msec after time t1, the detected temperature value THB of the battery 1 from the sensor 2 received by the EFI-ECU 4 (e.g., 21°C) is acquired as the calculation initial value, and at time t3, which is the timing of the next LIN communication 200 msec after time t2, the calculation of the above equation (1) starts. Then, as shown in Fig. 2, after time t3, as the temperature of the engine 6 rises, the detected temperature value THB from the sensor 2 gradually rises, and the estimated battery temperature value THBSM also gradually rises.

[0022] In the past, an impossible large value such as 200°C was always used as the initial value in the calculation of the above-mentioned equation (1), which resulted in the battery temperature estimate THBSM shown by the dashed line in Figure 3 deviating from the true temperature value (true value) shown by the solid line in Figure 3. However, by calculating equation (1) on the condition that the update flag is on, it is possible to obtain a battery temperature estimate THBSM that is close to the true temperature value (true value) shown by the solid line in Figure 3 without being influenced by the initial value such as 200°C.

[0023] In this way, since the estimated value of the battery fluid temperature does not deviate from the true value, it is possible to prevent a situation in which charging and discharging would be prohibited due to a deviation in the estimated value of the battery fluid temperature, even for battery fluid temperatures where charging and discharging control would normally be possible, as would be the case when charging and discharging control of battery 1 is performed based on a battery fluid temperature that deviates from the true value.This makes it possible to perform appropriate charging and discharging control of battery 1, such as starting charging and discharging control when the estimated value of the battery fluid temperature reaches, for example, 15°C after engine 6 has started, and prevents a deterioration in fuel efficiency due to inappropriate charging and discharging control of battery 1.

[0024] Next, the procedure for estimating the battery fluid temperature by the EFI-ECU 4 will be described with reference to the flowcharts of FIGS.

[0025] 4 shows the procedure for setting the update flag. When the ignition switch is turned on, the EFI-ECU 4 wakes up from a sleep state and starts operating, and LIN communication becomes possible, the battery temperature is detected by sensor 2 and transmitted to the EFI-ECU 4, and the detected temperature value THB of sensor 2 is received by the EFI-ECU 4. Even if the ignition switch is turned on, the EFI-ECU 4 does not receive the detected temperature value THB of sensor 2 until the EFI-ECU 4 wakes up and becomes possible to perform LIN communication.

[0026] Then, as shown in FIG. 4, when the EFI-ECU 4 is in a state where it can receive the detected temperature value THB of the sensor 2, it determines whether the received detected temperature value THB is within a predetermined range of -30°C to 150°C (step S1). If the determination result is YES, that is, if the detected temperature value THB is within the range of -30°C to 150°C, the update flag is turned ON (step S2), and then the operation ends.

[0027] On the other hand, even if the ignition switch is turned on, the EFI-ECU 4 does not receive the detected temperature value THB from sensor 2 until the EFI-ECU 4 wakes up and becomes capable of LIN communication. Therefore, it is determined that the detected temperature value THB is not within the range of -30°C to 150°C, and the judgment result in step S1 is NO. Alternatively, if the true detected temperature value THB transmitted from sensor 2 is not within the range of -30°C to 150°C, the judgment result in step S1 is also NO as an abnormality, the update flag is kept OFF (step S3), and the operation then ends.

[0028] In this way, when the ignition switch is turned on, the EFI-ECU 4 wakes up from its sleep state and starts operating, and whether LIN communication is possible is determined based on whether the update flag is ON.

[0029] Fig. 5 shows the procedure for the calculation process of the battery temperature estimate by the EFI-ECU 4. After the ignition switch is turned on, when the temperature value detected by the sensor 2 begins to be received normally by the EFI-ECU 4, as shown in Fig. 5, it is determined whether or not the update flag is ON (step S11). If the update flag is OFF and the determination result in step S1 is NO, the battery temperature estimate THBSM by the EFI-ECU 4 is set to a predetermined initial value such as 200°C (step S12), and then the operation ends.

[0030] Furthermore, if the update flag is ON and the judgment result in step S11 is YES, it is judged whether or not the EFI-ECU 4 has acquired the detected temperature value THB (e.g., 20°C) at time t2 shown in Figure 2 from the sensor 2 as the calculation initial value (step S13). If the judgment result is YES, the battery temperature estimated value THBSM is set to the calculation initial value acquired at time t2 (step S14). If the judgment result in step S13 is NO, it is assumed that the detected temperature value THB at time t3 of the next communication timing, which is different from the calculation initial value at time t2, has been acquired, and calculation of the above equation (1) is started (step S15). After that, the operation ends after step S14.

[0031] Therefore, according to the above-described embodiment, when the EFI-ECU 4 derives a current battery temperature estimate regarding the state of the battery 1 based on the output of the sensor 2 using a past battery temperature estimate, starting from a preset initial value, when the temperature detection value of the battery 1 acquired by the sensor 2 becomes a value within a predetermined range (-30°C to 150°C), the EFI-ECU 4 derives the current battery temperature estimate based on the battery temperature detection value instead of a preset initial value such as 200°C. This prevents the battery temperature estimate from being influenced by a large initial value that exceeds the predetermined range, prevents the battery temperature estimate from deviating significantly from the true value, and enables a battery temperature estimate close to the true value to be derived, thereby enabling accurate control when charging or discharging the battery 1 based on the battery temperature estimate.

[0032] Furthermore, as shown in Figure 2, calculation of the battery temperature estimate begins once LIN communication becomes possible after the ignition switch is turned on. Therefore, even if there is a time delay between when the ignition switch is turned on and when LIN communication becomes possible, it is possible to derive a battery temperature estimate that is close to the true value and to accurately control the charging and discharging of battery 1.

[0033] The present invention is not limited to the above-described embodiment, and various modifications other than those described above can be made without departing from the spirit of the present invention.

[0034] For example, in the above embodiment, the case has been described where the state data value relating to the state of the battery 1 is the temperature of the battery 1, but the state data value may also be a battery current value.

[0035] Furthermore, in the above embodiment, a case has been described in which the EFI-ECU 4 wakes up from a sleep state and starts operating when the ignition switch is turned on, and whether or not LIN communication is possible is determined based on whether or not the update flag is ON. However, this is not limited to the update flag, and in short, any configuration may be used as long as it can be determined that the EFI-ECU 4 wakes up from a sleep state and starts operating, and that LIN communication is possible, when the status data value relating to the battery status acquired by the acquisition means falls within a predetermined range.

[0036] In the above embodiment, the LIN communication is performed between the sensor 2 and the EFI-ECU 4. to Although the case where data is transmitted and received via a CAN has been described, the present invention can also be applied to a case where CAN (Controller Area Network) communication is performed, and the same effects as those of the above-described embodiment can be obtained. That is, the present invention can be applied to a case where an initial value is set in advance, and the current estimated value regarding the battery state is derived based on the output of the acquisition means and past estimated values, starting from the set initial value.

[0037] Furthermore, although the above-described embodiment describes the application of the present invention to a conventional vehicle that is driven only by an engine, the present invention can also be applied to a hybrid vehicle equipped with an auxiliary battery and used to control the charging and discharging of the auxiliary battery.

[0038] The present invention can be applied to a vehicle control device that estimates a state data value relating to the state of a battery, such as the battery fluid temperature, and controls the vehicle. [Explanation of symbols]

[0039] 1...Battery 2...Current and temperature sensor (acquisition means) 4...EFI-ECU (derivation means)

Claims

[Claim 1] a charging means for charging a battery mounted on the vehicle when an ignition switch is turned on; an acquisition means for acquiring a status data value relating to the status of the battery through LIN communication; a derivation means for deriving a current battery temperature estimation value by calculation using a preset initial value and a past battery temperature estimation value relating to the state of the battery, based on the state data value output from the acquisition means; the charging means starts charging the battery when the ignition switch is turned on; The derivation means After the ignition switch is turned on, when the status data value output from the acquisition means through the LIN communication becomes a value within a predetermined range, it is determined that the LIN communication has started normally, and an update flag is switched from off to on, and a current battery temperature estimation value is derived by the calculation using the status data value output from the acquisition means as a calculation initial value instead of the initial value, If the status data value output from the acquisition means through the LIN communication is not within the predetermined range after the ignition switch is turned on, it is determined that the LIN communication has not started normally, and the update flag is kept off and the calculation is not performed; The charging means starts charge / discharge control of the battery based on the current battery temperature estimated value derived by the calculation after the update flag is turned on by the derivation means. A vehicle control device comprising:

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