JP2017044175A - Internal combustion engine control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform an idling stop with improved appropriateness.SOLUTION: When a main battery is charged for a predetermined period T1 with an automatic stop of an internal combustion engine prohibited but an electric current cumulative value Isum, which represents a charging amount of the main battery during the period, does not reach a threshold charging amount Icrt corresponding to the predetermined period T1, an internal combustion engine control device determines that a detection value of a main battery current sensor has an error causing the main battery to have a discrepancy between an actual battery SOC and a battery SOC calculated by an ECM and reduces threshold values to prohibit idling stop operation and to resume the idling stop operation.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a control device for an internal combustion engine.

  For example, Patent Document 1 discloses a technique for performing idle stop execution determination using a detection value obtained by correcting an offset error of a current sensor that detects a charge / discharge current of a battery. In Patent Document 1, it is possible to avoid that it is determined that the idle stop execution condition is not satisfied due to the offset error included in the detection value of the current sensor, and the idle stop can be performed more appropriately.

JP 2013-92140 A

  However, in Patent Document 1 described above, the offset correction value is obtained using the average value of the current sensor detection values, and the magnitude of the offset error changes depending on the conditions, so it is difficult to obtain the offset correction value accurately. There is room for further improvement in making the idle stop more appropriate.

  An internal combustion engine control apparatus according to the present invention includes an internal combustion engine that is a drive source of a vehicle, a battery that can be charged by driving the internal combustion engine, a battery charge state detection unit that detects a charge state of the battery, When the stop condition is satisfied, the internal combustion engine is automatically stopped. When the predetermined restart condition is satisfied during the automatic stop of the internal combustion engine, the internal combustion engine is automatically restarted, and the state of charge of the battery is set to a predetermined idle stop prohibition. A control unit that prohibits automatic stop of the internal combustion engine until the charge state of the battery becomes equal to or greater than a predetermined idle stop re-permission threshold value that is greater than the idle stop prohibition threshold value when the battery charge state is smaller than a threshold value, and the battery charge state When there is an error in the state of charge of the battery detected by the detection unit, the idle stop prohibition threshold and the idling Or lowering the stop reauthorization threshold or is characterized by correcting to the battery state of charge is increased which is detected by the battery state detecting unit.

  According to the present invention, it is possible to prevent the opportunity for the internal combustion engine to automatically stop due to an error of the current sensor from being reduced, and it is possible to appropriately perform the automatic stop of the internal combustion engine. Therefore, it is possible to prevent the internal combustion engine from being automatically stopped due to an error in the detection value of the current sensor, and to improve the fuel consumption of the internal combustion engine.

BRIEF DESCRIPTION OF THE DRAWINGS Explanatory drawing which showed typically schematic structure of the control apparatus of the internal combustion engine which concerns on this invention. The characteristic view which shows the correlation with charge amount threshold value Icrt and battery temperature. The timing chart which shows the control content when the automatic stop of an internal combustion engine is prohibited. The flowchart which shows the flow of control in 1st Example. The flowchart which shows the flow of control in 2nd Example.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 is an explanatory view schematically showing a schematic configuration of a control device for an internal combustion engine 1 according to the present invention.

  The internal combustion engine 1 is mounted as a drive source in a vehicle such as an automobile. The internal combustion engine 1 drives an alternator 3 via a belt 2. The electric power generated by the alternator 3 is supplied to an in-vehicle electric load such as a headlamp (not shown), or the main battery 4 and the sub battery 5 are charged.

  The power generation voltage of the alternator 3 is controlled by a regulator 6 that receives a power generation command from the USM 14 described later.

  For example, when the power generated by the alternator 3 is insufficient, the main battery 4 and the sub-battery 5 are discharged so as to compensate for the shortage and supply power to the electric load.

  Note that a battery relay 7 is disposed between the main battery 4 and the sub-battery 5, and switching between which battery to charge or from which battery to supply power to the electric load is performed. Is possible.

  The charging / discharging current of the main battery 4 is detected by the main battery current sensor 8. The main battery current sensor 8 is connected to the negative terminal of the main battery 4 and measures the charge / discharge current flowing to the negative terminal side of the main battery 4. The main battery current sensor 8 is disposed close to the main battery 4 and can detect the temperature around the main battery 4. In the present embodiment, the temperature around the main battery 4 is regarded as the temperature of the main battery 4 and used.

  The charging / discharging current of the sub battery 5 is detected by the sub battery current sensor 9. The sub-battery current sensor 9 is connected to the negative terminal of the sub-battery 5 and measures the charge / discharge current flowing on the negative terminal side of the sub-battery 5. The sub-battery current sensor 9 is disposed close to the sub-battery 5 and can detect the temperature around the sub-battery 5. In this embodiment, the temperature around the sub-battery 5 is regarded as the temperature of the sub-battery 5 and used.

  Detection signals from the main battery current sensor 8 and the sub battery current sensor 9 are input to an ECM (engine control module) 10.

  The ECM 10 is a well-known digital computer including a CPU, a ROM, a RAM, and an input / output interface, and is supplied with power from, for example, the main battery 4.

  The ECM 10 receives signals from the main battery current sensor 8 and the sub-battery current sensor 9, a vehicle speed sensor 11 that detects the vehicle speed of the vehicle, and an accelerator that detects the accelerator opening APO from the depression amount of the accelerator pedal. Signals from an opening sensor 12, a brake pedal sensor 13 that detects ON / OFF of the brake pedal, and the like are input. In addition, information such as the supply status of electric power to the electric load from the USM (underhood switching module) 14 is input to the ECM 10. Note that the voltages of the main battery 4 and the sub battery 5 are detected by the ECM 10.

  The ECM 10 calculates the battery SOC (battery charge state) of the main battery 4 from the charge / discharge current, voltage, and the like of the main battery 4, for example. Further, the ECM 10 calculates the battery SOC (battery charge state) of the sub battery 5 from, for example, the charge / discharge current of the sub battery 5 and the voltage. The battery SOC represents the state of charge of the battery, and its value changes between 0 and 100 (%).

  The USM 14 transmits a power generation command to the regulator 6 based on a command from an ECM (engine control module).

  The ECM 10 automatically stops (idle stop) the internal combustion engine 1 when a predetermined automatic stop condition (idle stop condition) is satisfied, and a predetermined automatic restart condition (idle stop release condition) is set during automatic stop (during idle stop). If established, the internal combustion engine 1 is automatically restarted. That is, the ECM 10 corresponds to an SOC detection unit (battery charge state detection unit) and a control unit.

  The automatic stop condition is, for example, that the operation amount of the accelerator pedal is zero, the brake pedal is on, the vehicle speed is equal to or lower than a predetermined value, the battery SOC of the main battery 4 is equal to or higher than a predetermined idle stop prohibition threshold, etc. When it is satisfied, the internal combustion engine 1 automatically stops. The automatic restart condition is, for example, that the amount of operation of the accelerator pedal is not zero, the brake pedal is in an off state, the battery SOC of the main battery 4 is less than the idle stop prohibition threshold, etc., and any one of these conditions is satisfied Then, the internal combustion engine 1 is automatically restarted.

  When the battery SOC of the main battery 4 becomes smaller than the idle stop prohibition threshold, the internal combustion engine 1 is automatically stopped until the battery SOC of the main battery 4 becomes equal to or greater than a predetermined idle stop repermission threshold that is larger than the idle stop prohibition threshold. Is prohibited.

  Here, when there is a divergence between the current value detected by the main battery current sensor 8 and the actual current value, the battery SOC of the main battery 4 is actually greater than or equal to the idle stop re-permission threshold. Nevertheless, the battery SOC of the main battery 4 calculated by the ECM 10 may be smaller than the idle stop re-permission threshold value and automatic stop of the internal combustion engine 1 may not be permitted. That is, when the detected value of the main battery current sensor 8 includes an error, the automatic stop of the internal combustion engine 1 is prohibited more than necessary.

  If the main battery 4 is charged, it should be charged according to the charging time. Therefore, the charge amount of the main battery 4 at that time can be estimated from the charge time.

  Therefore, in the first embodiment, if the charge amount based on the detection value of the main battery current sensor 8 deviates from the charge amount estimated from the charge time, the actual battery SOC of the main battery 4 is Then, it is determined that there is a difference between the battery SOC of the main battery 4 calculated by the ECM 10.

  In the first embodiment, when the main battery 4 is charged while the automatic stop of the internal combustion engine 1 is prohibited, even if charging of the main battery 4 continues for a predetermined time T1, the current integrated value Isum which is the amount of charge to the main battery 4 during this time When (A · sec) does not reach the charge amount threshold value Icrt corresponding to the predetermined time T1, the detection value of the main battery current sensor 8 includes an error, and is calculated by the actual battery SOC of the main battery 4 and the ECM 10 Assuming that there is a deviation from the battery SOC of the main battery 4, the idle stop prohibition threshold and the idle stop re-permission threshold are lowered.

  As a result, it is possible to prevent the automatic stop of the internal combustion engine 1 from being prohibited more than necessary. That is, it is possible to prevent the chance that the internal combustion engine 1 automatically stops due to an error of the main battery current sensor 8 from being reduced, and the automatic stop of the internal combustion engine 1 is appropriately performed to improve the fuel consumption of the internal combustion engine. be able to.

  As shown in FIG. 2, the charge amount threshold value Icrt is set so as to increase as the battery temperature of the main battery 4 increases.

  The charging capacity of the battery varies depending on the battery temperature. Therefore, by changing the charge amount threshold Icrt in accordance with the battery temperature of the main battery 4, the internal battery is automatically stopped (idle) while the necessary charge amount is secured in the main battery 4 while preventing erroneous determination. Stop).

  In the first embodiment, as the temperature of the main battery 4 increases, the lowering rate per one time of the idle stop prohibition threshold and the idle stop re-permission threshold is set to be larger. In addition, a lower limit is set for each of the idle stop prohibition threshold and the idle stop re-permission threshold.

  Therefore, the change in the battery SOC of the main battery 4 is kept within a certain range, and deterioration of the main battery 4 can be suppressed.

  The lower limit value of the idle stop prohibition threshold is set such that the amount of decrease from the initial value of the idle stop prohibition threshold is, for example, about 1% of the battery capacity of the main battery 4. The lower limit value of the idle stop re-permission threshold is set such that the amount of decrease from the initial value of the idle stop re-permission threshold is, for example, about 1% of the battery capacity of the main battery 4.

  FIG. 3 is a timing chart showing the control contents when the automatic stop of the internal combustion engine 1 is prohibited in the first embodiment.

  At time t1, the battery SOC (characteristic line A indicated by the solid line) of the main battery 4 becomes smaller than the idle stop prohibiting threshold value (characteristic line B indicated by the alternate long and short dash line), and the automatic stop of the internal combustion engine 1 is prohibited. That is, at the timing of time t1, the idle stop permission flag is switched from “1 (permitted)” to “0 (not permitted)”. Further, charging of the main battery 4 is started from the timing of time t1.

  At time t2 when a predetermined time T1 has elapsed from time t1, the charge amount (characteristic line D indicated by the solid line) charged in the main battery 4 between time t1 and time t2 is the charge amount threshold Icrt (characteristic line E indicated by the broken line). Therefore, the error determination flag is “1”. The error determination flag is a flag representing the result of error determination. In this example, since the error determination is performed at the timing of time t2, the error determination flag is “0” at a timing other than time t2.

  When the error determination flag becomes “1” at time t <b> 2, it is determined that there is a difference between the actual battery SOC of the main battery 4 and the battery SOC of the main battery 4 calculated by the ECM 10.

  Then, from the timing of time t2, the idle stop prohibition threshold (characteristic line B indicated by a one-dot chain line) and the idle stop re-permission threshold (characteristic line C indicated by a broken line) are decreased. The amount of decrease in the idle stop prohibition threshold and the amount of decrease in the idle stop re-permission threshold are, for example, the same predetermined amount of decrease.

  In the example illustrated in FIG. 3, the battery SOC of the main battery 4 becomes equal to or higher than the idle stop re-permission threshold idle stop re-permission threshold due to the decrease in the idle stop prohibition threshold and the idle stop re-permission threshold at the time 2 time. At this timing, the idle stop permission flag is switched from “0 (not permitted)” to “1 (allowed)”.

  Note that when the idle stop prohibition threshold and the idle stop re-permission threshold are lowered, the charge amount threshold Icrt may also be lowered. In this case, the charge amount threshold Icrt used when the automatic stop of the internal combustion engine 1 is prohibited next time becomes smaller than the charge amount threshold Icrt used this time.

  FIG. 4 is a flowchart showing the flow of control in the first embodiment.

  In S1, it is determined whether the automatic stop of the internal combustion engine 1 is prohibited. If the automatic stop is prohibited, the process proceeds to S2. If the automatic stop is not prohibited, the current routine ends.

  In S2, a current integrated value Isum corresponding to the charge amount is calculated based on the current value detected by the main battery current sensor 8.

  In S3, it is determined whether or not it is within a predetermined time T1 after the automatic stop of the internal combustion engine 1 is prohibited. If the elapsed time since the automatic stop is prohibited is within the predetermined time T1, the process proceeds to S4, and if the elapsed time since the automatic stop is prohibited exceeds the predetermined time T1, the process proceeds to S8.

  In S4, it is determined whether or not an elapsed time after the automatic stop of the internal combustion engine 1 is prohibited is a predetermined time T1. If the elapsed time since the automatic stop is prohibited is a predetermined time T1, the process proceeds to S5. If the elapsed time after the automatic stop is disabled is not the predetermined time T1, the process proceeds to S2.

  In S5, the current integrated value Isum and the charge amount threshold Icrt are compared, and it is determined whether or not there is a difference between the actual battery SOC of the main battery 4 and the battery SOC of the main battery 4 calculated by the ECM10. I do. That is, in S5, the above-described error determination is performed.

  When the current integrated value Isum is smaller than the charge amount threshold value Icrt, there is an error in the detected value of the main battery current sensor 8, and the actual battery SOC of the main battery 4 and the battery SOC of the main battery 4 calculated by the ECM 10 It is determined that there is a difference between the two, and the process proceeds to S6.

  When the current integrated value Isum is equal to or greater than the charge amount threshold Icrt, there is no error in the detected value of the main battery current sensor 8, and the actual battery SOC of the main battery 4 and the battery SOC of the main battery 4 calculated by the ECM 10 It is determined that there is no deviation between them, and the process proceeds to S8.

  In S6, it is determined whether or not the idle stop prohibition threshold and the idle stop re-permission threshold are lower limit values. If the current values of the idle stop prohibition threshold and the idle stop re-permission threshold are not lower limits, respectively, the idle stop prohibition threshold and the idle stop re-permission threshold can be lowered, and the process proceeds to S7.

  If the current values of the idle stop prohibition threshold and the idle stop re-permission threshold are respectively lower limit values, the idle stop prohibition threshold and the idle stop re-permission threshold cannot be further reduced, and the process proceeds to S8.

  In S7, the idle stop prohibition threshold and the idle stop re-permission threshold are decreased.

  In S8, it is determined whether or not the prohibition of the automatic stop of the internal combustion engine 1 is released. If the battery SOC of the main battery 4 calculated by the ECM 10 is equal to or greater than the idle stop re-permission threshold, the process proceeds to S9, and if not, the current routine is terminated.

  In S9, the current integrated value Isum is set to “0”.

  Next, a second embodiment of the present invention will be described. Note that the same components as those in the first embodiment described above are denoted by the same reference numerals, and redundant description is omitted.

  The control device for the internal combustion engine 1 in the second embodiment has substantially the same configuration as that of the first embodiment described above, but the actual battery SOC of the main battery 4 and the battery SOC of the main battery 4 calculated by the ECM 10 The determination method for determining that there is a difference between the two and the correction target are different.

  As the battery SOC increases, the current acceptability of the main battery 4 decreases, so the charging current decreases. Therefore, the charge amount of the main battery 4 at that time can be estimated from the magnitude of the charge current detected by the main battery current sensor 8.

  Therefore, in the second embodiment, when the main battery 4 is charged while the automatic stop of the internal combustion engine 1 is prohibited, if the charging current detected by the main battery current sensor 8 is smaller than a predetermined current threshold Io, the calculation is performed by the ECM 10. It is determined that there is a divergence between the main battery 4 and the battery SOC.

  The current threshold Io is set in consideration of an error in the detection value of the main battery current sensor 8, and is set assuming that the detection value of the main battery current sensor 8 is smaller than the actual current value, for example.

  In the second embodiment, when the main battery 4 is charged while the automatic stop of the internal combustion engine 1 is prohibited, and the charging current detected by the main battery current sensor 8 is smaller than the current threshold Io, the detected value of the main battery current sensor 8 is Assuming that there is a difference between the actual battery SOC of the main battery 4 and the battery SOC of the main battery 4 calculated by the ECM 10, including the error, the battery SOC of the main battery 4 calculated by the ECM 10 is increased. to correct.

  As a result, it is possible to prevent the automatic stop of the internal combustion engine 1 from being prohibited more than necessary. That is, it is possible to prevent the chance that the internal combustion engine 1 automatically stops due to an error of the main battery current sensor 8 from being reduced, and the automatic stop of the internal combustion engine 1 is appropriately performed to improve the fuel consumption of the internal combustion engine. be able to.

  The battery charging capability varies depending on the battery temperature and the charging voltage. Therefore, in the second embodiment, the current threshold Io is set so as to increase as the battery temperature of the main battery 4 increases, and is set to increase as the charging voltage of the main battery 4 increases. Further, the correction amount of the battery SOC of the main battery 4 calculated by the ECM 10 is set to increase as the temperature of the main battery 4 increases and the charging voltage of the main battery 4 increases.

  For this reason, in the second embodiment, the current threshold Io is changed according to the battery temperature and the charging voltage of the main battery 4 to prevent erroneous determination, and the necessary amount of charge is secured in the main battery 4. Thus, an automatic stop (idle stop) of the internal combustion engine can be performed.

  In the second embodiment, the upper limit of the integrated value of the correction amount of the battery SOC of the main battery 4 calculated by the ECM 10 is set to be about 1% of the battery capacity of the main battery 4, for example. In other words, an upper limit is set for the number of corrections of the battery SOC of the main battery 4 calculated by the ECM 10.

  Therefore, the change in the battery SOC of the main battery 4 is kept within a certain range, and deterioration of the main battery 4 can be suppressed.

  FIG. 5 is a flowchart showing the flow of control in the second embodiment.

  In S21, it is determined whether or not the automatic stop of the internal combustion engine 1 is prohibited. If the automatic stop is prohibited, the process proceeds to S2. If the automatic stop is not prohibited, the current routine ends.

  In S22, the current value I, which is the detected value of the main battery current sensor 8, is compared with the current threshold value Io, and the difference between the actual battery SOC of the main battery 4 and the battery SOC of the main battery 4 calculated by the ECM 10 is detected. It is determined whether or not there is. That is, in S22, the error determination described above is performed.

  When the current value I is smaller than the current threshold Io, there is an error in the detection value of the main battery current sensor 8, and there is an error between the actual battery SOC of the main battery 4 and the battery SOC of the main battery 4 calculated by the ECM 10. It is determined that there is a divergence, and the process proceeds to S23.

When the integrated current value I is equal to or greater than the current threshold value Io, there is no error in the detected value of the main battery current sensor 8, and there is no error between the actual battery SOC of the main battery 4 and the battery SOC of the main battery 4 calculated by the ECM 10. To end the current routine,
In S23, it is determined whether or not the number of corrections for the battery SOC of the main battery 4 is within a specified number. Since an upper limit is set for the integrated value of the correction amount of the battery SOC of the main battery 4, the number of corrections for the battery SOC is also limited. If the number of corrections of the main battery 4 with respect to the battery SOC is within the specified number of times, correction to increase the battery SOC of the main battery 4 is possible, and the process proceeds to S24. If the number of corrections with respect to the battery SOC of the main battery 4 is not within the specified number of times, the correction to increase the battery SOC of the main battery 4 cannot be made any more, and the current routine is terminated.

  In S24, it correct | amends so that the battery SOC of the main battery 4 calculated by ECM10 may become large.

  In S23, it is determined whether or not the integrated value of the correction amount of the battery SOC of the main battery 4 calculated by the ECM 10 has reached the upper limit. If the integrated value has not reached the upper limit, the process proceeds to S24. Good.

  In each of the above-described embodiments, when the battery SOC of the sub-battery 5 becomes smaller than the predetermined idle stop prohibition threshold, the internal combustion engine 1 is maintained until the battery SOC of the sub-battery 5 becomes equal to or greater than the predetermined idle stop re-permission threshold. The automatic stop may be prohibited. In this case, in order to prevent the automatic stop of the internal combustion engine 1 from being unnecessarily prohibited due to an error included in the detection value of the sub battery current sensor 9, the sub battery 5 is operated in the same manner as the main battery 4 described above. The idle stop prohibition threshold and the idle stop re-permission threshold may be reduced, or the battery SOC of the sub battery 5 calculated by the ECM 10 may be increased.

  Further, in the first embodiment, when it is determined that there is an error in the detection value of the main battery current sensor 8, the idle stop prohibition threshold and the idle stop re-permission threshold are lowered, but the battery SOC is corrected so as to increase. It doesn't matter. Furthermore, in the second embodiment, when it is determined that there is an error in the detection value of the main battery current sensor 8, the battery SOC is corrected so as to increase, but the idle stop prohibition threshold and the idle stop re-permission threshold are reduced. It doesn't matter.

DESCRIPTION OF SYMBOLS 1 ... Internal combustion engine 3 ... Alternator 4 ... Main battery 8 ... Main battery current sensor 10 ... ECM

Claims (7)

An internal combustion engine as a drive source of the vehicle;
A battery that can be charged by driving the internal combustion engine;
A battery charge state detector for detecting a charge state of the battery;
When the predetermined stop condition is satisfied, the internal combustion engine is automatically stopped. When the predetermined restart condition is satisfied during the automatic stop of the internal combustion engine, the internal combustion engine is automatically restarted, and the state of charge of the battery is set to a predetermined idle state. A control unit that prohibits the automatic stop of the internal combustion engine until the charge state of the battery becomes equal to or greater than a predetermined idle stop re-permission threshold value that is greater than the idle stop prohibition threshold value when smaller than a stop prohibition threshold value,
When there is an error in the state of charge of the battery detected by the battery state-of-charge detection unit, the battery that is detected by the battery state-of-charge detection unit or lowering the idle stop prohibition threshold and the idle stop re-permission threshold A control apparatus for an internal combustion engine, wherein the charge state is corrected so as to increase. A current sensor for detecting the charge / discharge current of the battery;
The battery charge state detection unit detects based on the detection value of the current sensor,
Even if the battery is continuously charged for a predetermined time while the automatic stop of the internal combustion engine is prohibited, if the charge amount to the battery based on the detection value of the current sensor during this time does not reach the predetermined charge amount threshold, 2. The internal combustion engine according to claim 1, wherein the idle stop prohibition threshold and the idle stop re-permission threshold are lowered or corrected so that the battery charge state detected by the battery charge state detection unit is increased. Control device. A current sensor for detecting the charge / discharge current of the battery;
The battery charge state detection unit detects based on the detection value of the current sensor,
If the charging current to the battery is smaller than a predetermined current threshold even if the battery is charged while the internal combustion engine is not automatically stopped, the idle stop prohibiting threshold and the idle stop re-permission threshold are reduced, or 2. The control apparatus for an internal combustion engine according to claim 1, wherein the battery charge state detected by the battery charge state detection unit is corrected so as to increase.   The control apparatus for an internal combustion engine according to claim 2, wherein the predetermined charging amount threshold is set to increase as the battery temperature increases.   The control apparatus for an internal combustion engine according to claim 3, wherein the predetermined current threshold value is set to increase as the battery temperature increases.   2. The control device for an internal combustion engine according to claim 1, wherein a lower limit value is set for the idle stop prohibition threshold and the idle stop re-permission threshold.   2. The control apparatus for an internal combustion engine according to claim 1, wherein an upper limit is set for the number of corrections of the battery charge state.

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