JP2006170792A - Electronic controller - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electronic controller capable of performing appropriate abnormality detection of a sensor according to time variation of the failure rate. <P>SOLUTION: A CPU 130 in an ECU 100 obtains the lifetime operating time of each of a water temperature sensor 210, a speed sensor 220, an engine sensor 230, a luminous intensity sensor 240, and a throttle position sensor 250, and derives a failure rate of the sensor according to this lifetime operating time. Further, based on the failure rate of the sensor according to this lifetime operating time, the CPU 130 determines the abnormality detection processing timing of each sensor, and performs the sensor abnormality detection processing every time the abnormality detection processing timing arrives. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an electronic control device that performs various types of control related to sensors.

Conventionally, various sensors are provided in a vehicle, and an electronic control unit (ECU) controls each part of the vehicle based on information detected by these sensors (see, for example, Patent Document 1). For example, the light intensity sensor mounted on the vehicle detects the light intensity outside the vehicle, and the ECU turns on the lamp of the vehicle when the light intensity is equal to or less than a predetermined value. Thereby, for example, when the vehicle enters the tunnel, the lamp can be turned on without being operated by the driver.
Japanese Patent Laid-Open No. 11-22536

  The above-described conventional ECU uses a sensor value sampled at a predetermined fixed timing to detect an abnormality of each sensor. However, the failure rate of the sensor has a property that varies depending on the total use time, such as being high immediately after the start of use or after being used for a certain period of time, but being low during that time. Therefore, when processing for detecting an abnormality of each sensor is performed at the same timing as when the failure rate is high even when the failure rate is low, the ECU is used for processing that is not necessarily required, resulting in a heavy load.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an electronic control device capable of detecting an abnormality of an appropriate sensor in accordance with a time variation of a failure rate.

  The electronic control device according to the present invention includes a first acquisition unit that acquires the total usage time of the sensor, and a derivation unit that derives a failure rate according to the total usage time of the sensor acquired by the first acquisition unit. Determining means for determining the abnormality detection processing timing of the sensor based on the failure rate according to the total usage time derived by the deriving means.

  With this configuration, it is possible to determine the appropriate abnormality detection processing timing based on the failure rate that fluctuates with the total usage time of the sensor and perform the sensor abnormality detection processing, and further reduce the load on the device. Can be achieved.

  Further, in the electronic control device according to the present invention, the derivation unit corresponds to the total use time based on a bathtub curve representing a correspondence relationship between the total use time of the sensor and a failure rate corresponding to the total use time. The failure rate to be derived is derived.

  The correspondence relationship between the total usage time of a product such as a sensor and the failure rate generally follows a so-called bathtub curve. Therefore, it is possible to derive an appropriate sensor failure rate based on the bathtub curve.

  In the electronic control device according to the present invention, the determination unit shortens the cycle of the abnormality detection processing timing of the sensor as the failure rate corresponding to the total usage time increases.

  The electronic control device according to the present invention further includes a second acquisition unit that acquires a parameter that represents a degree of a factor that increases the failure rate of the sensor, and the determination unit is acquired by the second acquisition unit. The abnormality detection processing timing of the sensor is determined based on the parameter indicating the degree of the factor that increases the failure rate of the sensor.

  With this configuration, it is possible to determine a more appropriate abnormality detection processing timing in consideration of not only a failure rate corresponding to the total usage time of the sensor but also a factor that increases the failure rate of the sensor.

  In the electronic control device according to the present invention, the determination unit shortens the cycle of the abnormality detection processing timing of the sensor as the parameter indicating the degree of the factor that increases the failure rate of the sensor increases.

  Further, in the electronic control device according to the present invention, the determination unit corrects the failure rate corresponding to the total usage time based on a parameter representing a degree of a factor that increases the failure rate of the sensor, Based on the failure rate corresponding to the total usage time, the abnormality detection processing timing of the sensor is determined.

  Further, the electronic control device according to the present invention provides a sensor abnormality detection process that is uniquely determined by a failure rate corresponding to the total usage time and a failure rate corresponding to a parameter indicating a degree of a factor that increases the failure rate of the sensor. A failure rate corresponding to the total usage time acquired by the first acquisition unit from the table and a sensor failure acquired by the second acquisition unit. The sensor abnormality detection processing timing uniquely determined by the parameter representing the degree of the factor that increases the rate is obtained.

  In the electronic control device according to the present invention, the parameter indicating the degree of the factor that increases the failure rate of the sensor is an engine load factor when the sensor is mounted on a vehicle.

  In the electronic control device according to the present invention, the parameter indicating the degree of the factor that increases the failure rate of the sensor is the temperature of the sensor.

  In the electronic control device according to the present invention, the parameter indicating the degree of the factor that increases the failure rate of the sensor is water wetting of the sensor.

  In the electronic control device according to the present invention, the parameter indicating the degree of the factor that increases the failure rate of the sensor is the pH concentration of the liquid that wets the sensor.

  In the electronic control device according to the present invention, the parameter indicating the degree of the factor that increases the failure rate of the sensor is a road surface condition when the sensor is mounted on a vehicle.

  In the electronic control device according to the present invention, the parameter indicating the degree of the factor that increases the failure rate of the sensor is a past driving situation of the driver when the sensor is mounted on a vehicle.

  In the electronic control device according to the present invention, the parameter indicating the degree of the factor that increases the failure rate of the sensor is a current driving situation of the driver when the sensor is mounted on a vehicle.

  In the electronic control device according to the present invention, the parameter representing the degree of the factor that increases the failure rate of the sensor is a travel region of the vehicle when the sensor is mounted on the vehicle.

  In the electronic control device according to the present invention, the parameter indicating the degree of the factor that increases the failure rate of the sensor is the quality of the sensor.

  The electronic control device according to the present invention determines the sensor abnormality detection processing timing based on the failure rate that fluctuates with the total usage time of the sensor, and can perform the sensor abnormality detection processing at an appropriate timing. It becomes possible.

  Hereinafter, an electronic control unit (ECU) as an electronic control device according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1a is a diagram showing the configuration of the ECU. The ECU 100 shown in the figure is mounted on a vehicle, and is provided in each part of the vehicle to detect a temperature sensor 210 for detecting engine coolant temperature, a speed sensor 220 for detecting vehicle speed, and a load factor of the engine. The sensor values from the engine sensor 230, the light intensity sensor 240 for detecting the light intensity outside the vehicle, and the throttle position sensor 250 for detecting the throttle position (accelerator position) are acquired by sampling at a predetermined timing. Based on the acquired sensor value, similarly, the solenoid 310, the lamp 320, and the tire terminal 330 provided in each part of the vehicle are controlled. In addition, the ECU 100 performs processing (sensor abnormality detection processing) for detecting abnormality such as destruction of the water temperature sensor 210, the speed sensor 220, the engine sensor 230, the light intensity sensor 240, and the throttle position sensor 250.

  The ECU 100 includes an input interface circuit 110, an A / D converter 120, a CPU 130, a backup circuit 140, a constant voltage power supply 150, and an output interface circuit 150. Among these, the CPU 130 has a memory 132.

  The input interface circuit 110 inputs sensor values from a water temperature sensor 210, a speed sensor 220, an engine sensor 230, a light intensity sensor 240, and a throttle position sensor 250 (hereinafter referred to as “each sensor” as appropriate).

  The input interface circuit 110 also inputs sensor temperature, wiper operation information, pH concentration, road surface unevenness information, driver identification information, brake position information, steering wheel angle information, travel area information, in-vehicle camera information, and navigation information.

  The sensor temperature is the temperature of the water temperature sensor 210, the speed sensor 220, the engine sensor 230, the light intensity sensor 240, and the throttle position sensor 250, which are abnormality detection targets, and is output from, for example, thermometers provided in these sensors. The wiper operation information is output, for example, from a device that detects the operation of the wiper when the wiper provided in the vehicle is operating. The pH concentration is the pH concentration of the liquid that wets the water temperature sensor 210, the speed sensor 220, the engine sensor 230, the light intensity sensor 240, and the throttle position sensor 250, which are abnormality detection targets. For example, the pH concentration provided in each of these sensors Output from the detecting device. The road surface unevenness information is information representing the unevenness of the road surface on which the vehicle is traveling, and is output from, for example, a device that detects the suspension state of the vehicle. In-vehicle camera information, which is image data obtained by photographing with a road surface monitoring camera provided in the vehicle, and navigation information, which is road surface information output from the navigation device, are also used as information representing the unevenness of the road surface. The driver identification information is information for identifying an individual driver such as a driver's fingerprint, and is output from, for example, a device that detects a fingerprint provided on the vehicle. The brake position information is information indicating the depression state of the brake by the driver, and is output from, for example, a device that detects the depression state provided in the brake. The handle angle information is information indicating the rotation angle of the handle, and is output from, for example, a device that detects the rotation angle provided on the handle. The travel area information is information characterizing the travel area of the vehicle such as a flat land and a mountainous area, and is output from, for example, a navigation device or a beacon receiver mounted on the vehicle.

  The input interface circuit 110 classifies each input data into digital data and analog data, outputs the digital data to the CPU 130, and outputs the analog data to the A / D converter 120.

  The A / D converter 120 converts analog data from the input interface circuit 110 into digital data and outputs the digital data to the CPU 130.

  CPU 130 executes a control program in memory 132 to control each part of the vehicle. Specifically, the CPU 130 outputs the sensor values of the water temperature sensor 210, the speed sensor 220, the engine sensor 230, the light intensity sensor 240, and the throttle position sensor 250 output from the input interface circuit 110 and the A / D converter 120 at a predetermined timing. Based on these sensor values, the solenoid 310, the lamp 320, and the tire termination terminal 330 are controlled.

  FIG. 1 b is a diagram showing the configuration of the throttle position sensor 250 and the ECU 100. The throttle position sensor 250 shown in FIG. 1b detects the opening of the throttle operated by the driver and outputs the detected throttle opening to the CPU 130 in the ECU 100. Specifically, throttle position sensor 250 includes a resistor 251 that receives power supply from constant voltage power supply 150 in ECU 100 and a movable contact 252. On the other hand, in the ECU 100, a resistor r1 is provided between the constant voltage power supply 150 and the A / D converter 120, and a resistor r2 is provided between the A / D converter 120 and the ground. In accordance with the amount of throttle opening operated by the driver, the position where the movable contact 252 contacts with the resistor 251 moves, whereby the voltage VTA of the movable contact 252 changes. The CPU 130 in the ECU 100 can recognize the throttle opening by detecting the voltage VTA as throttle opening information via the A / D converter 120.

  The memory 132 in the CPU 130 stores total usage time information, time-failure rate information, parameter-failure rate information, a timing table, and operation status information.

  The total use time information represents the total use time of each of the water temperature sensor 210, the speed sensor 220, the engine sensor 230, the light intensity sensor 240, and the throttle position sensor 250. The total use time is, for example, the total time that the sensor is energized at a certain voltage or more, or the total time that the sensor outputs a value. The CPU 130 measures the total use time for each of these sensors, and stores it in the memory 132 as total use time information.

  The time-failure rate information is information set for each sensor, and shows the correspondence between the total usage time of the sensor and the failure rate (total usage time failure rate) determined according to the total usage time of the sensor. It is information to represent. FIG. 2 is a diagram illustrating an example of a correspondence relationship between the total usage time and the total usage time failure rate. As shown in the figure, the correspondence between the total usage time and the total usage time failure rate is expressed by a so-called bathtub curve. According to this bathtub curve, the total use time failure rate is high immediately after the start of use of the sensor due to an initial failure or the like, and thereafter, the total use time failure rate gradually decreases as the total use time increases. When the total usage time approaches, for example, a predetermined service time or exceeds the service life, the total service time failure rate gradually gradually increases again.

  The parameter-failure rate information is information set for each sensor and for each factor that increases the sensor failure rate. The parameter (factor parameter) that indicates the degree of the factor that increases the sensor failure rate and the factor This is information representing a correspondence relationship with a failure rate (factor parameter failure rate) determined according to a parameter.

  Factor parameters include the load factor of the engine mounted on the vehicle, the temperature of the sensor, the wetness of the sensor, the pH concentration of the liquid that wets the sensor, the road surface on which the vehicle travels, the past driving situation of the driver, the driver Current driving situation, vehicle travel area, and sensor quality. The factor parameter corresponding to the factor that increases the failure rate of these sensors and the factor parameter failure rate are, as shown in FIG. 3, a correspondence relationship that the factor parameter failure rate increases as the parameter value of the factor parameter increases. Have

  Specifically, the engine load factor is detected by the engine sensor 230, and the parameter value increases as the engine speed input via the input interface circuit 110 increases. The sensor temperature is the sensor temperature input via the input interface circuit 110, and the parameter value increases as the sensor temperature increases. The wetness of the sensor corresponds to the wiper operation information input via the input interface circuit 110, and the parameter value increases when the wiper is activated and the sensor is easily wetted. The pH concentration of the liquid that wets the sensor is the pH concentration input via the input interface circuit 110. When the sensor is made of metal, the parameter value increases as the acidity increases and the rust tends to rust. The condition of the road surface on which the vehicle travels corresponds to the road surface unevenness information input via the input interface circuit 110, and the parameter value increases as the vibration of the sensor increases because the road surface unevenness is large.

  The past driving situation of the driver corresponds to the driving situation information in the memory 132. The driving status information is set for each driver and indicates the level of driving importance of the driver. This driving state information is obtained from throttle opening information, brake position information, and steering wheel angle information from the throttle position sensor 250 input through the input interface circuit 110 in the past driving, and includes driver identification information. The parameter value increases as the driver's past driving situation is not polite and the vibration of the sensor increases. The current driving situation of the driver corresponds to the throttle opening information, the brake position information, and the steering wheel angle information from the throttle position sensor 250 input through the input interface circuit 110 during driving. The parameter value increases as the driving state of the sensor is not polite and the vibration of the sensor increases. The travel region of the vehicle corresponds to the travel region information input via the input interface circuit 110, and the parameter value increases as the environment is severe, such as a mountainous area. The sensor quality corresponds to information relating to the predetermined sensor quality, and the parameter value increases as the quality is lower.

  The timing table is set for each sensor, and is configured by abnormality detection processing timing uniquely determined by the total usage time failure rate and the factor parameter failure rate. FIG. 4 is a diagram illustrating an example of a timing table. In FIG. 4, the abnormality detection processing timing is uniquely determined for each range of the total usage time failure rate and for each range of the factor parameter failure rate. For example, when the total use time failure rate is in the range of a1 to a2 and the factor parameter failure rate is in the range of b2 to b3, the abnormality detection processing timing is every 24 ms.

  The total usage time information, time-failure rate information, parameter-failure rate information, timing table, and operation status information in the memory 132 are stored even when the ignition switch is turned off or the power supply from the battery power source is cut off. It is held by the power supplied from the constant voltage power supply 150 without being erased.

  The CPU 130 determines the abnormality detection processing timing based on the total usage time information, the time-failure rate information, the parameter-failure rate information, the timing table, and the operation status information in the memory 132 described above. Details of the operation for determining the abnormality detection processing timing will be described later. The CPU 130 performs sensor abnormality detection processing on the water temperature sensor 210, the speed sensor 220, the engine sensor 230, the light intensity sensor 240, and the throttle position sensor 250 every time the abnormality detection processing timing arrives.

  Next, the determination operation of the abnormality detection processing timing will be described with reference to a flowchart. FIG. 5 is a flowchart showing the determination operation of the first abnormality detection processing timing.

  When the ignition switch is turned on, the CPU 130 stores the total usage time information and the time-failure rate information corresponding to each of the water temperature sensor 210, the speed sensor 220, the engine sensor 230, the light intensity sensor 240, and the throttle position sensor 250. Read from 132. Further, the CPU 130 derives the total use time failure rate for each sensor based on the total use time information and the time-failure rate information (S101).

  Next, for each sensor, the CPU 130 determines the load factor of the engine mounted on the vehicle, the temperature of the sensor, the wetness of the sensor, the pH concentration of the liquid that wets the sensor, the situation of the road surface on which the vehicle travels, the past of the driver Necessary ones are selected from the driving condition, the current driving condition of the driver, the travel region of the vehicle, and the factor parameters of the sensor quality (S102). For example, for a sensor provided at a location where the water does not get wet, a factor parameter relating to the water wetness of the sensor is not necessary, and is thus excluded.

  Next, the CPU 130 corrects the total usage time failure rate based on the selected factor parameter for each sensor (S103). Specifically, the CPU 130 corrects the total usage time failure rate so that the total usage time failure rate increases as the parameter value of the selected factor parameter increases. Here, for example, when the parameter value of the factor parameter is equal to or greater than a predetermined value, correction is performed such that the total usage time failure rate is 1.2 times. When a plurality of factor parameters are selected for one sensor, the CPU 130 corrects the total usage time failure rate of the sensor based on the parameter values of the selected factor parameters. .

  Next, the CPU 130 determines the abnormality detection processing timing corresponding to each sensor so that the cycle of the abnormality detection processing timing becomes shorter as the corrected total usage time failure rate increases (S104). Thereafter, the CPU 130 performs sensor abnormality detection processing for each of the water temperature sensor 210, the speed sensor 220, the engine sensor 230, the light intensity sensor 240, and the throttle position sensor 250 every time the abnormality detection processing timing comes.

  Thus, the ECU 100 derives the total usage time failure rate for each of the water temperature sensor 210, the speed sensor 220, the engine sensor 230, the light intensity sensor 240, and the throttle position sensor 250, and further calculates this total usage time failure rate. Correction is performed based on a parameter representing the degree of the factor that increases the sensor failure rate. Then, ECU 100 determines the abnormality detection processing timing according to the corrected total usage time failure rate. Therefore, it is possible to determine the appropriate abnormality detection processing timing considering the failure rate that fluctuates with the total usage time of the sensor and the factors that increase the sensor failure rate, and to perform the sensor abnormality detection processing, Furthermore, it is possible to reduce the load.

  FIG. 6 is a flowchart showing the determination operation of the second abnormality detection processing timing. The operation of S201 and S202 is the same as the operation of S101 and S102 in FIG. For each of 250, a total use time failure rate is derived (S201), and a necessary one is selected from each factor parameter (S202).

  Next, the CPU 130 reads parameter-failure rate information corresponding to the selected factor parameter from the memory 132 for each sensor. Further, the CPU 130 acquires the factor parameter failure rate based on the parameter value of the factor parameter and the parameter-failure rate information (S204). When a plurality of factor parameters are selected for one sensor, the CPU 130 calculates a factor parameter failure rate corresponding to each of the selected factor parameters for the total usage time failure rate of the sensor. The average value of the plurality of factor parameter failure rates is calculated.

  Next, the CPU 130 refers to the timing table in the memory 132 (see FIG. 4) for each sensor, and is uniquely determined by the total usage time failure rate derived in S201 and the factor parameter failure rate acquired in S203. The abnormality detection processing timing is determined (S204). The timing table shown in FIG. 4 is configured such that the cycle of the abnormality detection processing timing becomes shorter as the total usage time failure rate is larger and as the factor parameter failure rate is larger. Therefore, the CPU 130 refers to the timing table shown in FIG. 4 so that the cycle of the abnormality detection processing timing is shortened as the total usage time failure rate is larger and the factor parameter failure rate is larger. The abnormality detection processing timing corresponding to is determined. Thereafter, the CPU 130 performs sensor abnormality detection processing for each of the water temperature sensor 210, the speed sensor 220, the engine sensor 230, the light intensity sensor 240, and the throttle position sensor 250 every time the abnormality detection processing timing comes.

  Thus, the ECU 100 derives the total usage time failure rate for each of the water temperature sensor 210, the speed sensor 220, the engine sensor 230, the light intensity sensor 240, and the throttle position sensor 250, and further calculates the total usage time failure rate. The abnormality detection processing timing uniquely determined by the failure rate corresponding to the parameter indicating the degree of the factor that increases the failure rate of the sensor is determined. Therefore, it is possible to determine the appropriate abnormality detection processing timing considering the failure rate that fluctuates with the total usage time of the sensor and the factors that increase the sensor failure rate, and to perform the sensor abnormality detection processing, Furthermore, it is possible to reduce the load.

  In the above-described embodiment, the ECU 100 determines the abnormality detection processing timing in consideration of the factor that increases the failure rate of the sensor together with the total usage time failure rate, but the abnormality is considered only in consideration of the total usage time failure rate. You may make it determine a detection process timing.

  As described above, the electronic control device according to the present invention can perform sensor abnormality detection processing at an appropriate timing, can further reduce the load, and is useful as an electronic control device. .

It is a figure which shows the whole structure of ECU. It is a figure which shows a part of ECU. It is a figure which shows an example of the correspondence of a total use time and a total use time failure rate. It is a figure which shows the correspondence of a factor parameter and a factor parameter failure rate. It is a figure which shows an example of a timing table. It is a flowchart which shows the determination operation | movement of a 1st abnormality detection process timing. It is a flowchart which shows the determination operation | movement of a 2nd abnormality detection process timing.

Explanation of symbols

100 ECU
110 Input interface circuit 120 A / D converter 130 CPU
132 Memory 140 Backup circuit 150 Constant voltage power supply 210 Water temperature sensor 220 Speed sensor 230 Engine sensor 240 Light intensity sensor 250 Throttle position sensor 251 Resistance 252 Movable contact

Claims (16)

First acquisition means for acquiring the total usage time of the sensor;
Derivation means for deriving a failure rate according to the total usage time of the sensor acquired by the first acquisition means;
An electronic control unit comprising: a determination unit that determines an abnormality detection processing timing of the sensor based on a failure rate according to the total usage time derived by the deriving unit. The derivation unit derives a failure rate corresponding to the total use time based on a bathtub curve representing a correspondence relationship between the total use time of the sensor and the failure rate corresponding to the total use time. Electronic control unit. 3. The electronic control device according to claim 1, wherein the determination unit shortens the cycle of the abnormality detection processing timing of the sensor as the failure rate corresponding to the total usage time increases. Second acquisition means for acquiring a parameter representing a degree of a factor that increases a failure rate of the sensor;
The determination unit determines the abnormality detection processing timing of the sensor based on a parameter representing a degree of a factor that increases the failure rate of the sensor acquired by the second acquisition unit. The electronic control apparatus as described in. The electronic control device according to claim 4, wherein the determination unit shortens the cycle of the abnormality detection processing timing of the sensor as the parameter indicating the degree of the factor that increases the failure rate of the sensor increases. The determination means corrects the failure rate corresponding to the total usage time based on a parameter representing the degree of a factor that increases the failure rate of the sensor, and based on the failure rate corresponding to the corrected total usage time The electronic control device according to claim 4, wherein an abnormality detection processing timing of the sensor is determined. A table configured by sensor abnormality detection processing timing uniquely determined by a failure rate corresponding to the total usage time and a failure rate corresponding to a parameter indicating a degree of a factor that increases the failure rate of the sensor;
The determination means is a parameter representing the degree of a factor that increases the failure rate corresponding to the total use time acquired by the first acquisition means from the table and the sensor failure rate acquired by the second acquisition means. The electronic control device according to claim 4, wherein the abnormality detection processing timing of the sensor uniquely determined by The electronic control unit according to any one of claims 4 to 7, wherein the parameter representing the degree of a factor that increases the failure rate of the sensor is an engine load factor when the sensor is mounted on a vehicle. The electronic control device according to claim 4, wherein the parameter indicating the degree of a factor that increases the failure rate of the sensor is the temperature of the sensor. 10. The electronic control device according to claim 4, wherein the parameter indicating the degree of a factor that increases the failure rate of the sensor is water wetting of the sensor. 11. The electronic control device according to claim 4, wherein the parameter representing the degree of a factor that increases the failure rate of the sensor is a pH concentration of a liquid that wets the sensor. The electronic control device according to any one of claims 4 to 11, wherein the parameter representing the degree of a factor that increases the failure rate of the sensor is a road surface condition when the sensor is mounted on a vehicle. The electronic control device according to any one of claims 4 to 12, wherein the parameter representing the degree of a factor that increases the failure rate of the sensor is a past driving situation of the driver when the sensor is mounted on a vehicle. The electronic control device according to any one of claims 4 to 13, wherein the parameter representing the degree of a factor that increases the failure rate of the sensor is a current driving situation of the driver when the sensor is mounted on a vehicle. The electronic control device according to any one of claims 4 to 14, wherein the parameter representing the degree of a factor that increases the failure rate of the sensor is a travel region of the vehicle when the sensor is mounted on the vehicle. The electronic control device according to claim 4, wherein the parameter representing the degree of a factor that increases the failure rate of the sensor is the quality of the sensor.

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