JP3660147B2 - Abnormality detection device for exhaust secondary air supply device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
  The present invention relates to an exhaust secondary air supply device that supplies secondary air to an exhaust passage with an electric air pump in order to reduce harmful components in engine exhaust gas, and in particular, the electric air pump, the air supply passage, or the above-mentioned The present invention relates to an abnormality detection device for detecting an abnormal state of a flow control valve provided in an air supply passage.
[0002]
[Prior art]
  As a method of detecting an abnormality in the exhaust secondary air supply device, an O provided in the exhaust passage is used.₂Those using sensors are known. This is because if the exhaust secondary air supply device is functioning normally, the secondary air is supplied to the exhaust passage.₂It utilizes the fact that the sensor is in an oxygen-excess state and outputs a signal indicating a lean state.
[0003]
  As an abnormality detection device for an exhaust secondary air supply device, one disclosed in Japanese Patent Application Laid-Open No. 8-61051 is known. In this method, a power value is calculated from the current value and voltage value of the electric air pump, and an abnormal state of the electric air pump is detected based on whether or not the power value is within a predetermined range.
[0004]
[Problems to be solved by the invention]
  By the way, when the battery that supplies power to the electric air pump is in a state of insufficient charge or has deteriorated, or when the electric power steering device, discharge headlight, air conditioner, power window device, etc. that consumes a large amount of power are operated, In other words, when the charge / discharge balance of the battery is lost, the current consumption decreases due to a decrease in the voltage that drives the electric air pump. May decrease.
[0005]
  The present invention has been made in view of the above circumstances, and an object of the present invention is to make it possible to accurately detect an abnormal state of the exhaust secondary air supply device even when the charge / discharge balance of the battery is lost.
[0006]
[Means for Solving the Problems]
  In order to achieve the above object, according to the first aspect of the present invention, there is provided an electric air pump that supplies exhaust secondary air to an exhaust passage of an engine, and a battery that supplies electric load including the electric air pump. Voltage detection means for detecting a voltage value, current detection means for detecting a current value flowing through the electric air pump, and an abnormality detection means for detecting an abnormal state based on the current value detected by the current detection means An abnormality detection device for an exhaust secondary air supply device, wherein the abnormality detection means corrects the current value according to the voltage value.by doingCalculate the correction current valueAnd thatCorrection current valueInDetect abnormal conditions based onIn the above, the abnormality detecting means isAn abnormal state is detected based on a change in the correction current value accompanying the operation of the electric air pump.In addition, when the change in the current value detected by the current detection means exceeds the threshold value, the detection of the abnormal state is temporarily stopped, and whether or not to execute the temporary stop is determined after the electric air pump is started. This is performed after the set time set based on the set value for the electric air pump inrush current stabilization wait and the set value for the electric load fluctuation stabilization wait is elapsed.An abnormality detection device for an exhaust secondary air supply device is proposed.
[0007]
  According to the above configuration, even if the voltage value of the battery that supplies power to the electric load including the electric air pump changes, the current value flowing through the electric air pump is corrected according to the voltage value, and the corrected current value is calculated. This correction current valuechange ofBy detecting the abnormal state based on the above, it is possible to compensate for the influence of the change in the voltage value of the battery and detect the abnormal state with high accuracy.AlsoThe abnormality detection unit stops detecting the abnormal state when the change in the current value detected by the current detection unit exceeds the threshold value.SoFor example, if the battery voltage value temporarily changes greatly due to the inrush current of an electrical load such as auxiliary machinery, and the change in the current value detected by the current detection means exceeds the threshold value, the abnormality detection means detects the abnormal state.TemporaryCanceldo it,It is possible to prevent false detection.In this case, whether or not to temporarily stop detection of the abnormal condition is determined after the electric air pump is started, the setting value for waiting for the electric air pump inrush current stabilization and the setting for waiting for the electric load fluctuation stabilization This is performed after the set time set based on the value elapses.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
  Hereinafter, embodiments of the present invention will be described based on examples of the present invention shown in the accompanying drawings. 1 to 12 show an embodiment of the present invention. FIG. 1 is an overall configuration diagram of an exhaust secondary air supply device, FIG. 2 is a flowchart of an electric air pump abnormality detection main routine, and FIG. 3 is an IAP automatic hysteresis. 4 is a flowchart of a control IAPUMP calculation subroutine, FIG. 5 is a flowchart of a monitor execution permission condition establishment judgment subroutine, FIG. 6 is a flowchart of an electrical load change monitor suspension condition subroutine, and FIG. 7 is a flow characteristic deterioration. FIG. 8 is a graph showing the relationship between the discharge pressure and current value of the electric air pump for each battery voltage value, and FIG. 9 is a diagram showing a table for retrieving the IAP correction table value KIAPVB from the battery voltage value VB. FIG. 10 shows whether the monitor execution permission condition is satisfied and the flow rate deterioration Time chart for explaining the gender detection, FIG. 11 is a time chart, Figure 12 illustrating the monitor implementation permission condition satisfaction judgment is a time chart for explaining the electrical load variation during monitoring pause condition.
[0009]
  As shown in FIG. 1, an exhaust gas purification catalyst 2 for purifying exhaust gas is provided in an exhaust passage 1 extending from the engine E, and the exhaust secondary air is provided in the exhaust passage 1 upstream of the exhaust gas purification catalyst 2. The downstream end of the air supply passage 3 of the supply device is connected. In the air supply passage 3, an air cleaner 4, an electric air pump 5, and a flow rate control valve 6 are sequentially provided from the upstream side to the downstream side. The electronic control unit U constituting the abnormality detecting means of the present invention controls ON / OFF of the motor 7 that drives the electric air pump 5 and ON / OFF of the flow rate control valve 6 formed of a solenoid valve. The signal from the current sensor 8 that detects the value of the current flowing through 7 and the voltage value of the battery 10 that supplies power to the electric load 9 such as the electric air pump 5 and electric power steering device, discharge headlight, air conditioner, power window device, etc. Based on the signal from the voltage sensor 11 to be detected, an abnormality in the electric air pump 5, the flow control valve 6 or the air supply passage 3 is detected.
[0010]
  The exhaust secondary air supply device activates the exhaust gas purification catalyst 2 by driving the electric air pump 5 for a predetermined time after the engine E is started to supply air to the exhaust passage 1 and at the same time in the exhaust gas. This is to oxidize harmful components such as carbon monoxide and render them harmless. At that time, the flow control valve 6 is closed when the electric air pump 5 is not driven, and the exhaust gas flows backward to the air supply passage 3. To prevent. In this embodiment, when the electric air pump 5 is driven after the engine E is started, the flow rate control valve 6 is opened with a predetermined time delay without opening the flow rate control valve 6 at the same time. Thus, the abnormality of the electric air pump 5, the flow control valve 6 or the air supply passage 3 is detected. The operation will be described below with reference to the flowcharts of FIGS.
[0011]
  The flowchart of FIG. 2 shows a main routine for detecting abnormality of the electric air pump. First, hysteresis is given to the current value (AD conversion value) IAP of the electric air pump 5 detected by the current sensor 8 in step S1. That is, the current value IAP of the electric air pump 5 detected by the current sensor 8 with the rotation of the motor 7 that drives the electric air pump 5 fluctuates minutely in a sine wave form, so that the fluctuation behaves like noise and is erroneous. May cause detection. Therefore, processing for removing only a substantial variation by removing a minute variation of the current value IAP is performed. Details of step S1 will be described later based on the flowchart of FIG.
[0012]
  In subsequent step S2, the current value IAP is corrected using the voltage value (A / D conversion value) VB of the battery 10 detected by the voltage sensor 11, thereby controlling the electric air pump 5 and the flow control valve 6 or exhausting two. A corrected control current value IAPUMP used when detecting an abnormality in the next air supply device is calculated. Details of step S2 will be described later based on the flowchart of FIG.
[0013]
  In the subsequent step S3, it is determined whether or not the operating condition of the engine E is a condition suitable for detecting abnormality of the exhaust secondary air supply device. Details of step S3 will be described later based on the flowchart of FIG.
[0014]
  In the subsequent step S4, a monitor execution permission condition satisfaction flag F to be described later If MCND 60A is cleared to “0” and the monitor execution permission condition is not satisfied, in step S7, a primary detection determination value ISAVO and a secondary detection determination value DISAV described later are set to an initial value 0 and will be described later. Temporary normality determination flag F KOK60A is cleared to the initial value “0”. On the other hand, in step S4, the monitor execution permission condition satisfaction flag F If MCND 60A is set to “1” and the monitor execution permission condition is satisfied, the process proceeds to step S5.
[0015]
  In step S5, if the voltage value VB of the battery 10 is temporarily greatly reduced due to the inrush current of the electric load 9 such as an air conditioner, for example, the abnormality detection of the exhaust secondary air supply device cannot be accurately performed. Therefore, the control for temporarily stopping the abnormality detection is performed. Details of step S6 will be described later based on the flowchart of FIG.
[0016]
  In subsequent step S6, whether or not an abnormality has occurred in the electric air pump 5, the flow rate control valve 6 or the air passage 3 is specifically detected using the corrected control current value IAPUMP. Details of step S7 will be described later based on the flowchart of FIG.
[0017]
  Next, the content of the step S1 (IAP automatic hysteresis) will be specifically described based on the flowchart of FIG.
[0018]
  First, in step S11, the current value IAP of the current value (AD conversion value) IAP of the electric air pump 5_(n)Is the current value IAPN of the current value IAPN before the automatic hysteresis is reflected._(n)And In subsequent step S12, the current value IAPN of the current value IAPN before the automatic hysteresis is reflected._(n)And the previous value IAPH of the current value IAPH after the automatic hysteresis is reflected_(n-1)Absolute value of deviation from IAPN_(n)-IAPH_(n-1)| Is compared with the threshold value DIAPHYS reflecting the automatic hysteresis._(n)-IAPH_(n-1)When | ≦ DIAPHYS is satisfied and the fluctuation of the current value IAP is small, the fluctuation is regarded as a fluctuation accompanying the rotation of the motor 7, and in step S13, the previous value of the current value IAPH after the automatic hysteresis is reflected. IAPH_(n-1)Current value IAPH after automatic hysteresis is reflected without updating_(n)And On the other hand, in step S12, | IAPN_(n)-IAPH_(n-1)|> DIAPHYS is established and if the fluctuation of the current value IAP is large, it is determined that the fluctuation is caused by a factor other than the fluctuation accompanying the rotation of the motor 7, and the current value before the automatic hysteresis is reflected in step S14. Current value of IAPN IAPN_(n)Is the current value IAPH of the current value IAPH after the automatic hysteresis is reflected._(n)Update.
[0019]
  Thus, by giving an automatic hysteresis to the current value IAP of the electric air pump 5, it is possible to remove a sinusoidal variation accompanying the rotation of the motor 7 and obtain an appropriate current value IAP.
[0020]
  Next, the contents of step S2 (control IAPUMP calculation) will be specifically described based on the flowchart of FIG.
[0021]
  First, in step S21, the voltage value VB of the battery 10 detected by the voltage sensor 11 is applied to the correction table of FIG. 9 to retrieve the IAP correction table value KIAPVB, and this IAP correction table value KIAPVB is reflected on the automatic hysteresis. By applying to the subsequent current value IAPH, the corrected control current value IAPUMP is calculated based on the following equation.
[0022]
                IAPUMP ← IAPH × KIAPVB
  As apparent from FIG. 9, the IAP correction table value KIAPVB retrieved from the correction table is 1.0 when the voltage value VB of the battery 10 is 14 V (regulator voltage of the AC generator) as a reference, When the voltage value VB exceeds the reference value 14V, it becomes smaller than 1.0 and the control current value IAPUMP is corrected in a decreasing direction. Conversely, when the voltage value VB falls below the reference value 14V, it becomes larger than 1.0. The control current value IAPUMP is corrected in the increasing direction.
[0023]
  The meaning of the above characteristics of the control current value IAPUMP will be described below.
[0024]
  FIG. 8 shows the relationship between the discharge pressure DP (horizontal axis) of the electric air pump 5 and the current value IAP (vertical axis) of the electric air pump 5 while changing the voltage value VB of the battery 10 from 10V to 15V every 1V. The result of measuring the relationship is shown. As can be seen from the figure, the voltage values VB have DP-IAP characteristics that are parallel to each other, and the slope of the characteristic line (ΔIAP / ΔDP) is substantially constant. Further, when the discharge pressure DP is constant, the current value IAP of the electric air pump 5 increases as the voltage value VB of the battery 10 increases. The discharge pressure DP is 10 kPa (corresponding to the back pressure during idling) and the voltage value VB is 14 V (corresponding to the regulated voltage of the AC generator). The discharge pressure is 10 kPa at each voltage value VB. The IAP correction table value KIAPVB in FIG. 9 is obtained by dividing the current value IAP necessary for obtaining the current value IAP in the reference state.
[0025]
  Therefore, when the voltage value VB of the battery 10 is the normal value of 14V, the current value IAP of the electric air pump 5 is about 35A, but when the voltage value VB is reduced to 12V, for example, the current value IAP is about 30A. The decrease in the current value IAP from 35A to 30A is not caused by an abnormal state, but is merely caused by a change in the voltage value VB of the battery 10, thus preventing it from being mistaken as an abnormal state. Therefore, the current value IAP of 30 A is corrected to a current value 35 A when the voltage value VB is 14 V, which is a normal value. Specifically, the IAP correction table value KIAPVB = 1.159 when the voltage value VB = 12V is retrieved from the correction table of FIG. 9, and the current value IAP = 30A is multiplied by this IAP correction table value KIAPVB = 1.159. By doing so, the corrected control current value IAPUMP = 35 A can be obtained.
[0026]
  Next, based on the flowchart of FIG. 5 and the time charts of FIG. 10 and FIG. 11, the contents of step S3 (determination of monitoring execution permission condition) will be specifically described.
[0027]
  First, in step S31, the electric air pump system monitor execution permission flag F Refer to GO60A. Electric air pump system monitor execution permission flag F The GO 60A represents the result of failure detection executed by the centralized management unit. If it is not set to “1” and any failure has occurred, the monitor execution permission condition establishment flag is set in step S48. F MCND60A is cleared to “0” to prohibit monitoring.
[0028]
  In step S31, the electric air pump system monitor execution permission flag F If GO60A is set to "1", in step S32, energization permission determination flag F Reference APHTSTP. Energization permission determination flag F APHTSTP represents permission or prohibition of the operation of the electric air pump 5 based on the cooling water temperature in the start mode, and is set to “1”, so that the exhaust gas purification catalyst 2 is activated. If it is not necessary to drive the electric air pump 5, the monitor execution permission flag F in HOT-IDLE, which will be described later, in step S43. After APODHT is cleared to “0”, a monitor execution permission condition satisfaction flag F is set in step S48. MCND60A is cleared to “0” to prohibit monitoring.
[0029]
  In step S32, the energization permission determination flag F If APHTSTP is not set to “1”, and therefore the operation of the electric air pump 5 is permitted and the engine E is in the start mode in step S33, that is, if the engine speed Ne is less than 500 rpm. After step S43, the monitor execution permission condition satisfaction flag F is obtained in step S48. MCND60A is cleared to “0” to prohibit monitoring.
[0030]
  If the engine speed Ne is 500 rpm or more in step S33 and the basic mode (see FIG. 10) has already been entered after exiting the start mode, whether the basic mode stabilization wait timer tmAPCSST has timed out in step S34. Judge whether or not. The basic mode stabilization wait timer tmAPCSST is set at the same time as the start of the engine E, and starts counting down as soon as the basic mode is entered. When the time is up, the TMAPCSST has elapsed since entering the basic mode, and the idling is started. It is judged that the state is stable.
[0031]
  If the basic mode stabilization wait timer tmAPCSST has not timed out in step S34, in step S46, the current current value for control IAPUMP is set to a first reference current value IAP0 which will be described later, and a primary which will be described later in step S47. After the detection failure determination counter ctAPOBD is set to the set value CTAPOBD for each loop, the monitor execution permission condition satisfaction flag F is set in step S48. MCND60A is cleared to “0” to prohibit monitoring.
[0032]
  When the basic mode stabilization wait timer tmAPCSST has timed out in step S34, in step S35, the atmospheric pressure PA is equal to or higher than the threshold value PAFS 60A corresponding to the high altitude, and the threshold corresponding to the cooling water temperature TW is the low water temperature. It is determined whether or not the value is TWFS 60A or more. As a result, when at least one of the two conditions is not satisfied, that is, when the atmospheric pressure is low or the cooling water temperature is low, the process proceeds to step S44. In step S44, the monitor execution delay timer tmFS60AD waits for time-up. In step S45, the monitor execution stabilization wait timer tmFS60A is set to the set value TMFS60A, and the primary detection failure determination counter ctAPOBD is set to 0. The monitor execution permission condition satisfaction flag F MCND60A is cleared to “0” to prohibit monitoring.
[0033]
  Thus, by prohibiting the execution of the monitor after waiting for the monitor execution delay timer tmFS60AD to expire, the execution and the stop of the monitor are frequently performed when the determination result in step S35 changes between YES and NO. It can be prevented from being repeated.
[0034]
  When the conditions in step S35 are satisfied, the monitor execution delay timer tmFS60AD is set to the set value TMFS60AD in step S36, and then in step S37, the engine E is idling, the vehicle speed pulse Vp is 0, and the battery It is determined whether or not the voltage value VB of 10 is equal to or greater than the monitor execution lower limit threshold value VBFS60A (10.0 V), and if any of the conditions is not satisfied, the monitor execution permission is allowed in step S48 through step S45. Condition satisfaction flag F MCND60A is cleared to “0” to prohibit monitoring.
[0035]
  When all the conditions in step S37 are satisfied, in step S38, the monitor execution permission flag F in the HOT-IDLE is satisfied. Refer to APODHT. Monitor execution permission flag F in HOT-IDLE APODHT is not intended to activate the exhaust gas purification catalyst 2 but to monitor again when the monitor when the electric air pump 5 is driven to activate the exhaust gas purification catalyst 2 is not established. It is a flag that permits driving of the electric air pump 5 for the purpose of achieving the above.
[0036]
  In step S38, the monitoring execution permission flag F in HOT-IDLE If APODHT is not set to “1”, and therefore the electric air pump 5 is driven to activate the exhaust gas purification catalyst 2, step S39 is skipped and the process proceeds to step S40. In step S40, the monitor execution stabilization waiting timer tmFS60A waits for time up, and in step S41, the monitor execution permission condition satisfaction flag F MCND 60A is set to “1” to permit monitoring.
[0037]
  On the other hand, in step S38, the monitoring execution permission flag F in HOT-IDLE When APODHT is set to “1” and therefore the electric air pump 5 is driven not for activating the exhaust gas purification catalyst 2, the routine proceeds to step S39 and the electric air pump energizing time counter ctAP is moved. It is determined whether or not the time is up. The electric air pump energization time counter ctAP is the drive time of the electric air pump 5 necessary for activating the exhaust gas purification catalyst 2, and the map is searched simultaneously with the start of the engine E. Until this electric air pump energization time counter ctAP expires, the monitor execution permission condition satisfaction flag F is passed in step S48 through step S45. MCND60A is cleared to “0” to prohibit monitoring.
[0038]
  In step S39, when the electric air pump energization time counter ctAP times out, in step S40, the monitor execution stabilization waiting timer tmFS60A waits for time up. In step S41, the monitor execution permission condition satisfaction flag F MCND 60A is set to “1” to permit monitoring.
[0039]
  Next, the operation when the monitor is not established immediately after the start of the engine E will be further described based on the time chart of FIG.
[0040]
  After the electric air pump 5 is driven after the engine E is started and the flow rate control valve 6 is opened, before the secondary detection failure confirmation counter ctSAVOBD is timed up and monitoring is completed, for example, the engine speed Ne is idle. It is assumed that the monitor is not established beyond the rotation speed (see step S37). After that, when the engine speed Ne becomes equal to or lower than the idle speed, the electric air pump 5 is re-driven and the flow control valve 6 is restarted for the purpose of monitoring after waiting for the monitor execution stabilization wait timer tmFS60A to expire. Is done.
[0041]
  Next, based on the flowchart of FIG. 6 and the time charts of FIGS. 10 and 12, the content of the step S5 (electric load fluctuation monitor suspension condition) will be specifically described.
[0042]
  First, in step S51, when the count value of the primary detection failure confirmation counter ctAPOBD (see FIG. 10) counted down with the activation of the electric air pump 5 becomes equal to or less than CTAPOBD−CTAPSTB + CTAPELC, it is determined whether or not the monitor should be paused. Therefore, the process proceeds to step S52. Here, CTAPOBD is a set value for determining the primary detection failure, CTAPSTB is a set value for waiting for stabilization of the electric air pump inrush current, and CTAPELC is a set value for waiting for stabilization of electric load fluctuation.
[0043]
  In subsequent step S52, the electric load fluctuation level determination value DIAPELC is set to the current value IAPH of the current value IAPH after the automatic hysteresis is reflected._(n)And the previous value IAPH_(n-1)Absolute value of difference from IAPH_(n)-IAPH_(n-1)Calculate as |.
[0044]
            DIAPELC ← ｜ IAPH_(n)-IAPH_(n-1)｜
  In subsequent step S53, the electric load fluctuation level determination value DIAPELC is compared with the monitor temporary stop threshold value DIAPSSSP. If the timer tmELCSTB has timed up, in step S55, the monitor pause flag F APELC is cleared to “0”, and the monitor is not suspended.
[0045]
  On the other hand, when DIAPELC ≧ DIAPSSSP is established in step S53 and the electric load fluctuation level is large, the electric load fluctuation stabilization waiting timer tmELCSTB is set to the set value TMELCSTB in step S58, and the monitor is temporarily stopped in step S59. Flag F Set APELC to "1"TemporaryPerform a stop. Even if DIAPELC ≧ DIAPSSSP is not established in step S53 and the electric load fluctuation level is small, if the electric load fluctuation stabilization waiting timer tmELCSTB is being counted in step S54, the monitor temporary stop flag is similarly set to “ Set to “1” to suspend the monitor. As described above, once the monitor is paused, the monitor is suspended until at least the electric load fluctuation stabilization wait timer tmELCSTB times up, so that frequent monitor stop / execution is repeated. Can be prevented.
[0046]
  As described above, for example, when the electric load 9 having a large power consumption such as an air conditioner is turned on, when the current value IAP of the electric air pump 5 fluctuates greatly due to the inrush current, the monitor is changed. By temporarily stopping, erroneous detection of an abnormal state can be prevented in advance.
[0047]
  Thus, when the monitor pause flag is cleared to “0” in step S55, the temporary normality determination flag F is determined in step S56. If KOK60A is not set to "1", that is, before the position (1) in FIG. 10, the temporary detection failure determination counter ctAPOBD is decremented in step S57, and the temporary normality determination flag F is determined in step S56. If KOK60A is set to "1", that is, after the position (1), the secondary detection failure determination counter ctSAVOBD is decremented in step S60.
[0048]
  Next, based on the flowchart of FIG. 7 and the time chart of FIG. 10, the contents of step S6 (flow characteristic deterioration detection) will be specifically described.
[0049]
  First, in step S61, the monitor pause flag F If APELC is cleared to “0” and the monitor is not temporarily stopped and the primary detection failure determination counter ctAPOBD is counting in step S62, the secondary detection failure determination counter ctSAVOBD is set for each loop in step S63. Set to set value CTSAVOBD. In subsequent step S64, the provisional normality determination flag F If KOK60A is not set to “1” and the primary detection failure determination counter ctAPOBD becomes equal to or lower than CTAPOBD-CTAPSTB (primary detection electric air pump inrush current stabilization counter) in step S65, that is, the electric air pump 5 When the stabilization wait time has elapsed since the activation of the control current and the control current value IAPUMP is stabilized (see (1) in FIG. 10), the process proceeds to step S66.
[0050]
  In step S66, a first deviation DIAP is calculated by subtracting the first reference current value IAP0 when the electric air pump 5 is stopped from the control current value IAPUMP. In step S67, the control current value IAPUMP at that time is calculated as the first deviation DIAP. 2 Reference current value ISAVO. In a succeeding step S68, it is determined whether or not the first deviation DIAP is between a lower limit value DIAPOKL and an upper limit value DIAPOKH. As a result of the determination, if the first deviation DIAP is between the lower limit value DIAPOKL and the upper limit value DIAPOKH, it is determined in step S69 that the electric air pump 5 is normally normal, and the temporary normal determination flag F KOK60A is set to “1”, and the primary detection failure determination counter ctAPOBD is set to 0 in step S70.
[0051]
  As described above, when the control air current value IAPUMP is stabilized after the stabilization waiting time has elapsed after the electric air pump 5 is started, the control current value IAPUMP and the first reference current value when the electric air pump 5 is stopped. If the first deviation DIAP from IAP0 is within a predetermined range, it can be determined that the electric air pump 5 is operating normally. If the first deviation DIAP is abnormally small, there is a possibility that the electric air pump 5 is not energized. If the first deviation DIAP is abnormally large, the electric air pump 5 enters an overload state such as a lock. Large current may be flowing.
[0052]
  On the other hand, in step S62, the primary detection failure determination counter ctAPOBD is timed up (see (2) in FIG. 10), and in step S71, the temporary normality determination flag F If KOK60A is not set to “1”, it means that the first deviation DIAP does not fall within the predetermined range in (1) of FIG. 10, and it is determined that there is some abnormality in step S72. Judgment flag F FSD60A is set to “1”, and abnormality detection completion flag F is set in step S78 DONE 60A is set to “1” and the abnormality detection is terminated.
[0053]
  On the other hand, in step S71, the temporary normality determination flag F If KOK60A is set to “1”, abnormality detection of the flow control valve 6 and the air supply passage 3 is executed in subsequent steps S73 to S77.
[0054]
  First, in step S73, a second deviation DISAV is calculated by subtracting the current control current value IAPUMP from the second reference current value ISAVO calculated in step S67, and in the subsequent step S74, the second deviation DISAV is secondarily detected. If it is not less than the normal determination threshold value DISAVOK, it is determined in step S75 that the flow control valve 6 and the air supply passage 3 are normal, and the normal determination flag F After setting OK60A to “1”, an abnormality detection completion flag F is set in step S78. The DONE 60A is set to “1” to end the abnormality detection.
[0055]
  On the other hand, when the second deviation DISAV is less than the secondary detection normality determination threshold value DISAVOK in step S74 and the secondary detection failure determination counter ctSAVOBD has timed out in step S76 (see (3) in FIG. 10). In step S77, it is determined that the flow control valve 6 or the air supply passage 3 is abnormal, and the abnormality determination flag F After the FSD 60A is set to “1”, the abnormality detection completion flag F is set in step S78. DONE 60A is set to “1” and the abnormality detection is terminated.
[0056]
  Thus, when the primary detection failure determination counter ctAPOBD has timed up and the stabilization wait time has elapsed since the flow control valve 6 opened, the flow control valve 6 is in the state of (2) in FIG. If the valve is normally shifted from the closed state to the open state and the air supply passage 3 is not clogged or damaged, the load of the electric air pump 5 is reduced, so that the second deviation DISAV is the threshold value for determining whether the secondary detection is normal. Should be greater than DISAVOK. However, if the flow control valve 6 does not open due to a failure, or if the air supply passage 3 upstream of the flow control valve 6 is clogged even if the flow control valve 6 is opened, the load of the electric air pump 5 Therefore, the second deviation DISAV becomes less than the secondary detection normal determination threshold value DISAVOK, and an abnormality can be detected. When the flow control valve 6 has failed to open from the beginning, or when the air supply passage 3 between the electric air pump 5 and the flow control valve 6 is broken, a signal for opening the flow control valve 6 is given. Since the load of the electric air pump 5 does not change even if it is output, the second deviation DISAV becomes less than the secondary detection normal determination threshold value DISAVOK, and an abnormality can be detected.
[0057]
  As mentioned above, although the Example of this invention was explained in full detail, this invention can perform a various design change in the range which does not deviate from the summary.
[0058]
【The invention's effect】
  As aboveBookAccording to the invention, even if the voltage value of the battery that supplies power to the electric load including the electric air pump changes, the current value flowing through the electric air pump is corrected according to the voltage value to calculate a corrected current value. Correction current valuechange ofBy detecting the abnormal state based on the above, it is possible to compensate for the influence of the change in the voltage value of the battery and detect the abnormal state with high accuracy.
[0059]
  AlsoSupplementIf the battery voltage value temporarily changes greatly due to the inrush current of the electrical load such as machinery, and the change in the current value detected by the current detection means exceeds the threshold value, the abnormality detection means stops detecting the abnormal state. Therefore, it is possible to prevent false detections from occurring.In this case, whether or not to temporarily stop detection of the abnormal condition is determined after the electric air pump is started, the setting value for waiting for the electric air pump inrush current stabilization and the setting for waiting for the electric load fluctuation stabilization This is performed after the set time set based on the value elapses. Therefore, for example, when an electric load with large power consumption such as an air conditioner is turned ON, when the current value of the electric air pump fluctuates greatly due to the inrush current, the monitor is temporarily stopped, It is possible to prevent erroneous detection of an abnormal state.
[Brief description of the drawings]
1 is an overall configuration diagram of an exhaust secondary air supply device.
FIG. 2 is a flowchart of an electric air pump abnormality detection main routine.
FIG. 3 is a flowchart of an IAP automatic histing subroutine.
FIG. 4 is a flowchart of a control IAPUMP calculation subroutine.
FIG. 5 is a flowchart of a monitor execution permission condition establishment determination subroutine.
FIG. 6 is a flowchart of a monitor suspension condition subroutine when an electric load fluctuates.
FIG. 7 is a flowchart of a flow characteristic deterioration detection subroutine.
FIG. 8 is a graph showing the relationship between the discharge pressure and current value of the electric air pump for each battery voltage value.
FIG. 9 is a view showing a table for retrieving an IAP correction table value KIAPVB from a battery voltage value VB.
FIG. 10 is a time chart for explaining monitoring execution permission condition establishment determination and flow rate deterioration characteristic detection;
FIG. 11 is a time chart for explaining determination of whether or not a monitor execution permission condition is satisfied
FIG. 12 is a time chart for explaining monitor suspension conditions when electric load changes
[Explanation of symbols]
1 Exhaust passage
5 Electric air pump
8 Current sensor (current detection means)
10 battery
11 Voltage sensor (voltage detection means)
DIAPSSP threshold
E engine
IAP current value
IAPUMP correction current value
U Electronic control unit (abnormality detection means)
VB voltage value

Claims (1)

Voltage value (VB) of an electric air pump (5) that supplies exhaust secondary air to the exhaust passage (1) of the engine (E) and a battery (10) that supplies power to an electric load including the electric air pump (5) Voltage detection means (11) for detecting the current, current detection means (8) for detecting the current value (IAP) flowing through the electric air pump (5), and the current value (IAP) detected by the current detection means (8) And an abnormality detection device (U) for detecting an abnormal state based on the abnormality detection device of the exhaust secondary air supply device,
The abnormality detecting means (U) is, the correction current value by correcting in accordance with the current value the voltage value (IAP) (VB) was calculated (IAPUMP), based on the corrected current value (IAPUMP) For detecting abnormal conditions ,
The abnormality detection means (U) detects an abnormal state based on a change in the correction current value (IAPUMP) accompanying the operation of the electric air pump (5), and the current detected by the current detection means (8). When the change of the value (IAP) exceeds the threshold value (DIAPSSSP), the detection of the abnormal state is suspended,
The determination as to whether or not to execute the suspension is made after the electric air pump (5) is started up, a set value (CTAPSTB) for waiting for electric air pump inrush current stabilization and a set value for waiting for electric load fluctuation stabilization. An abnormality detection device for an exhaust secondary air supply device, which is performed after a set time set based on (CTAPELC) elapses .

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