Patent Application
20250076407
This application claims priority to Japanese Patent Application No. 2023-140232 filed on Aug. 30, 2023, and Japanese Patent Application No. 2023-173683 filed on Oct. 5, 2023, each incorporated herein by reference in its entirety.
The technology disclosed herein relates to a control device.
Japanese Unexamined Patent Application Publication No. 11-139223 (JP 11-139223 A) discloses a control device for detecting an abnormality in a vehicle wire harness. The control device detects the abnormality in the wire harness based on a temperature detected by a thermistor wound around the wire harness.
In a vehicle, a foreign object such as water may enter a connector of a temperature sensor. In this case, the terminal in the connector is short-circuited by the foreign object, and thus the temperature detected by the temperature sensor exhibits an abnormal value. Therefore, the entry of the foreign object into the connector can be detected by monitoring the temperature detected by the temperature sensor. When a small amount of the foreign object (typically water) enters the connector, however, the foreign object moves in the connector in response to acceleration and deceleration of the vehicle. Therefore, the terminal in the connector is short-circuited by the foreign object or the short circuit is eliminated. In this case, the temperature detected by the temperature sensor exhibits abnormal values intermittently. Therefore, it is difficult to determine whether the fluctuation has occurred due to entry of a foreign object into the connector or due to noise.
The present specification provides a technology capable of determining that a foreign object has entered a connector.
A first aspect disclosed herein discloses a control device to be connected to a temperature sensor disposed in a drive device of a vehicle via a connector from an outside of the drive device. The control device is configured to perform:
As described above, when the foreign object enters the connector, the terminal in the connector is short-circuited by the foreign object. In this case, the temperature detected by the temperature sensor exhibits an abnormal value. Therefore, the sudden temperature change condition that the first temperature difference is equal to or higher than the first predetermined temperature is satisfied. When a small amount of the foreign object enters the connector, the terminal in the connector is short-circuited intermittently, and the sudden temperature change condition is also satisfied intermittently. The sudden temperature change condition may be satisfied accidentally due to influence of noise. When the cause is the small amount of the foreign object that has entered the connector, however, the sudden temperature change condition is repeatedly satisfied at relatively short intervals. Therefore, determination is made that the foreign object has entered the connector when the sudden temperature change condition is repeatedly satisfied up to the predetermined number of times with intervals in the first predetermined period. Thus, the entry of the foreign object can be determined accurately even if the small amount of the foreign object has entered the connector.
In a second aspect, according to the first aspect, the control device may further be configured to perform:
When the determination that the second temperature difference is equal to or higher than the second predetermined temperature is made continuously for the second predetermined period, an abnormality (for example, disconnection of a wiring portion of the temperature sensor) different from the abnormality that the foreign object has entered the connector may occur. With the above configuration, the control device can determine that the foreign object has entered the connector, and can determine that the different abnormality has occurred.
In a third aspect, according to the first or second aspect, the first determination process may include:
In the above configuration, the control device clears the counted number of times when the sudden temperature change condition is not satisfied for the first predetermined period. With such a configuration, it is possible to determine more accurately that the foreign object has entered the connector than in a configuration in which the counted number of times is not cleared.
In a fourth aspect, according to any one of the first to third aspects, the temperature sensor may be a sensor configured to detect a temperature of a lubricating liquid in the drive device.
In a fifth aspect, according to any one of the first to fourth aspects, the drive device may include an electric motor configured to drive a wheel of the vehicle.
In a sixth aspect, according to any one of the first to fifth aspects, the control device may further be configured to perform:
The amount of fluctuation in the detected temperature varies depending on the type of foreign object entering the connector. With the above configuration, the control device can appropriately determine the type of the foreign object that has entered the connector based on the first temperature difference.
In a seventh aspect, according to the sixth aspect,
Foreign objects that are likely to enter the connector are water and metal. Therefore, the control device can determine whether the foreign object that has entered the connector is water or metal.
Features, advantages, and technical and industrial significance of exemplary embodiments of the disclosure will be described below with reference to the accompanying drawings, in which like signs denote like elements, and wherein:
As illustrated in
The drive device 10 includes an electric motor 20 and a gear unit 22. The electric motor 20 is a device that drives the left front wheel 16L and the right front wheel 16R of the vehicle 2 by electric power supplied from the battery 12. The electric motor 20 is connected to the left front wheel 16L and the right front wheel 16R via a gear unit 22. The gear unit 22 includes a planetary gear mechanism 24 and a differential mechanism 26. The planetary gear mechanism 24 amplifies the output torque of the electric motor 20. The differential mechanism 26 distributes the power transmitted from the planetary gear mechanism 24 to the left front wheel 16L and the right front wheel 16R.
Lubricating fluid for lubricating and cooling the electric motor 20 and the gear unit 22 is stored in the drive device 10. A temperature sensor 28 for detecting the temperature of the lubricating liquid is attached to the drive device 10. The temperature sensor 28 includes a detection unit 30, a wiring portion 32, and a connector 34. A detection unit 30 is connected to one end of the wiring portion 32, and a connector 34 is connected to the other end. The connector 34 is electrically connected to a connector of the control device 14.
The control device 14 is a controller including a memory 14A. The control device 14 controls the operation of the electric motor 20 and the like in accordance with a program (not shown) stored in the memory 14A. A temperature sensor 28 is electrically connected to the control device 14. The control device 14 is configured to periodically (e.g., at a period of tens of milliseconds) acquire the temperature detected by the temperature sensor 28. The memory 14A stores a first abnormality flag and a second abnormality flag. The first abnormality flag indicates either “OFF” indicating that an abnormality caused by the intrusion of water into the connector 34 has not occurred, or “ON” indicating that an abnormality has occurred in the temperature sensor 28 due to the intrusion of water into the connector 34 being determined. The second abnormality flag indicates either “OFF” indicating that an abnormality caused by the intrusion of metal into the connector 34 has not occurred, or “ON” indicating that an abnormality has occurred in the temperature sensor 28 due to the intrusion of metal into the connector 34 being determined.
An abnormality determination process executed by the control device 14 of the vehicle 2 will be described with reference to
In S10, the control device 14 calculates the first temperature difference by using the detected temperature periodically acquired from the temperature sensor 28. The first temperature difference is an absolute difference between the acquired detected temperature and the detected temperature (hereinafter, referred to as “previous detected temperature”) acquired one cycle ago. The previously detected temperature is stored in the memory 14A.
In S12, the control device 14 monitors that a sudden temperature change condition in which the first temperature difference is equal to or higher than the first predetermined temperature is satisfied. As the first predetermined temperature, a threshold value for detecting an abnormality in the temperature detected by the temperature sensor 28 is set. As an example, the first predetermined temperature is 10° C. When the first temperature difference is equal to or higher than the first predetermined temperature, the control device 14 determines YES in S12, and proceeds to S14.
In S14, the control device 14 stores the previously detected temperature as a particular previously detected temperature in the memory 14A.
In S20, the control device 14 calculates the second temperature difference by using the detected temperature periodically acquired and the specified previously detected temperature stored in the memory 14A. The second temperature difference is an absolute difference between the acquired detected temperature and a specific previous detected temperature.
In S22, the control device 14 monitors that the second temperature difference becomes equal to or lower than the second predetermined temperature. As the second predetermined temperature, a threshold value for detecting that the temperature sensor 28 is normal is set. As an example, the second predetermined temperature is 5° C. When the second temperature difference is equal to or lower than the second predetermined temperature, the control device 14 determines YES in S22 and proceeds to S30.
In addition, the control device 14 monitors that the first elapsed time is equal to or longer than the first determination time in S24 simultaneously with the monitoring of S22. The first elapsed time is an elapsed time since S12 is determined to be YES. When the first elapsed time is equal to or longer than the first determination time, the control device 14 determines YES in S24 and proceeds to S26.
In S26, the control device 14 determines that an anomaly has been determined in the temperature sensor 28. The abnormality in this case is an abnormality in which the wiring portion 32 of the temperature sensor 28 is disconnected, an abnormality in which a large amount of water enters the connector 34, or the like. If it is determined that an abnormality has occurred in the temperature sensor 28, the control device 14 notifies the user that an abnormality has occurred in the temperature sensor 28. As an example, the control device 14 turns on a warning lamp (not shown) of the instrument panel. Thus, the user can know that an abnormality has occurred in the temperature sensor 28. When S26 ends, the control device 14 ends the process of
In addition, in S30, the control device 14 calculates the first thermal difference.
In S32, the control device 14 monitors that the sudden temperature change condition (that is, the first temperature difference is equal to or higher than the first predetermined temperature) is satisfied. When the sudden temperature change condition is satisfied, the control device 14 determines YES in S32, and proceeds to S34.
In S34, the control device 14 counts up the number of times of establishment N stored in the memory 14A. The number of times of establishment N indicates the number of times that the sudden temperature change condition is satisfied at an interval within the second determination time described later.
In S36, the control device 14 determines whether or not the number of times of establishment N in the memory 14A has reached a predetermined number of times (for example, 10 times). The control device 14 proceeds to S38 when the number of times of establishment N has reached a predetermined number of times (YES in S36). On the other hand, when the number of times of establishment N has not reached the predetermined number of times (NO in S36), the control device 14 returns to S30.
In S38, the control device 14 determines that an anomaly has been determined in the temperature sensor 28. The abnormality detected in this case is, for example, an abnormality in which a small amount of water has entered the connector 34. If it is determined that an abnormality has occurred in the temperature sensor 28, the control device 14 notifies the user that an abnormality has occurred in the temperature sensor 28. As an example, the control device 14 turns on the warning lamp of the instrument panel. As a result, the control device 14, which can know that an abnormality has occurred in the temperature sensor 28, ends the process of
In addition, the control device 14 monitors, concurrently with the monitoring of S32, that the second elapsed time is equal to or longer than the second determination time in S40. The second elapsed time is a time elapsed without the sudden temperature change condition being satisfied. As an example, the second determination time is 20 seconds and is longer than the first determination time. When the second elapsed time is equal to or longer than the second determination time, the control device 14 determines YES in S40 and proceeds to S42.
In S42, the control device 14 determines that the temperature sensor 28 is normal and clears the number of times of establishment N. When S42 ends, the control device 14 returns to S10.
Referring to
Each S50, S52 is similar to S10, S12 of
In S54, the control device 14 determines whether or not the first temperature difference is equal to or higher than the third predetermined temperature. The third predetermined temperature is a threshold value for determining whether the foreign object that has entered the connector 34 is water or metal. Specifically, the control device 14 converts the first temperature difference into the amount of change in the voltage, and specifies the amount of change in the resistance value (hereinafter, referred to as “the amount of change in the resistance value”) by using the amount of change in the converted voltage. Then, the control device 14 determines whether or not the resistance value change amount is equal to or greater than a predetermined change amount. When the resistance-value change amount is equal to or greater than the predetermined change amount, the control device 14 determines that the first temperature difference is equal to or greater than the third predetermined temperature (YES in S54), and proceeds to S60. On the other hand, when the resistance value change amount is less than the predetermined change amount, the control device 14 determines that the first temperature difference is less than the third predetermined temperature (NO in S54), and proceeds to S70.
In S60, the control device 14 determines whether or not an abnormality is determined in the temperature sensor 28 in the abnormality determination process of
In S62, the control device 14 determines that the foreign object that has entered the connector 34 is water.
In S64, the control device 14 changes the first anomaly flag from “OFF” to “ON”. In response to the first abnormal flag being changed to “ON”, the control device 14 lowers the upper limit of the output value of the electric motor 20 to the first upper limit value. When S64 ends, the control device 14 ends the process of
S70 is similar to S60.
In addition, in S72, the control device 14 determines that the foreign object that has entered the connector 34 is metallic.
In S74, the control device 14 changes the second anomaly flag from “OFF” to “ON”. In response to the second anomaly flag being changed to “ON”, the control device 14 lowers the upper limit of the output value of the electric motor 20 to the second upper limit value smaller than the first upper limit value. That is, the control device 14 switches the upper limit of the output value of the electric motor 20 according to the type of the foreign object that has entered the connector 34. When S64 ends, the control device 14 ends the process of
With reference to
The detected temperature between the time T0 and T1 is substantially constant in the temperature TE1. Therefore, in T1 from the time T0, the vehicle 2 determines that the first temperature difference is less than the first predetermined temperature (NO in S12 of
At time T2, the terminals in the connector 34 are shorted due to water ingress into the connector 34 of the temperature sensor 28. Consequently, the detected temperature of the temperature sensor 28 suddenly changes from the temperature TE1 to the temperature TE2. That is, the detected temperature indicates an abnormal value. The absolute difference between the temperature TE2 and the temperature TE1 is greater than the first predetermined temperature. Therefore, the vehicle 2 determines that the first temperature difference is equal to or higher than the first predetermined temperature (YES in S12), and stores the temperature TE1 in the memory 14A as a particular previously detected temperature (S14).
In the time T2, the vehicle 2 determines that the first temperature difference is equal to or higher than the first predetermined temperature (YES in S52 of
As in this case, when a small amount of water enters the connector 34, the terminals in the connector 34 are short-circuited by the water or the short-circuit is eliminated in accordance with the acceleration and deceleration of the vehicle 2. By eliminating the short circuit of the terminal in the connector 34, the detected temperature becomes a temperature TE3 lower than the temperature TE2 by the second predetermined temperature at the time T3 that is prior to the elapse of the first determination time from the time T2. Then, the vehicle 2 determines that the second temperature difference is equal to or lower than the second predetermined temperature (YES in S22 of
Then, at time T4 that is prior to the elapse of the second determination time after the second temperature difference becomes equal to or lower than the second predetermined temperature, the terminal in the connector 34 is short-circuited by water. Consequently, the detected temperature suddenly changes from the temperature TE1 to the temperature TE2. In this instance, the vehicle 2 determines that the first temperature difference is equal to or higher than the first predetermined temperature (YES in S32), counts up the number of times of establishment N to “1” (S34), and determines that the number of times of establishment N has not reached the predetermined number (NO in S36). Thereafter, the detected temperature returns to the temperature TE1.
Next, at time T5 that is prior to the elapse of the second determination time after the first temperature difference becomes equal to or higher than the first predetermined temperature, the terminal in the connector 34 is short-circuited by water. Consequently, the detected temperature suddenly changes from the temperature TE1 to the temperature TE2. In this instance, the vehicle 2 determines that the first temperature difference is equal to or higher than the first predetermined temperature (YES in S32), counts up the number of times of establishment N to “2” (S34), and determines that the number of times of establishment N has not reached the predetermined number (NO in S36). Thereafter, the terminals in the connector 34 are short-circuited by water or the short-circuited terminals are eliminated. As a result, the sudden temperature change condition is intermittently established. Then, the number of times of establishment N is counted up in response to the establishment of the sudden temperature change condition (S34).
At the time T6 after the number of times of establishment N is counted up to “9”, the terminal in the connector 34 is short-circuited by water. Consequently, the detected temperature suddenly changes from the temperature TE1 to the temperature TE2. In this instance, the vehicle 2 determines that the first temperature difference is equal to or higher than the first predetermined temperature (YES in S32), counts up the number of times of establishment N to “10” (S34), and determines that the number of times of establishment N has reached the predetermined number (YES in S36). In this instance, the vehicle 2 determines that an anomaly has been determined in the temperature sensor 28 (S38), and turns on the warning lamp of the instrument panel. Thus, the user can know that an abnormality has occurred in the temperature sensor 28. In this way, even if a small amount of water enters the connector 34, the intrusion of water into the connector 34 of the temperature sensor 28 is detected.
In the time T6, the vehicle 2 determines that an abnormality is determined in the temperature sensor 28 in the abnormality determination process of
As described above, the control device 14 first executes a process of periodically acquiring the detected temperature by the temperature sensor 28, and a process of calculating a first temperature difference (S10, S30 of
When water enters the connector 34, the terminals in the connector 34 are short-circuited by the water. When the temperature detected by the temperature sensor 28 indicates an abnormal value, a sudden temperature change condition in which the first temperature difference is equal to or higher than the first predetermined temperature is satisfied (YES in S32 of
In addition, when the sudden temperature change condition is satisfied, the control device 14 stores the last detected temperature (S14), and further executes a second calculation process (S20) of calculating a second temperature difference which is an absolute difference between the detected temperature detected thereafter and the stored last detected temperature. The control device 14 further executes a second determination process (S26) of determining that an anomaly has occurred in the temperature sensor 28 when the determination that the second temperature difference is equal to or higher than the second predetermined temperature is continued for the first determination time shorter than the first predetermined period (an example of the “second predetermined period”) (YES in S24).
When the determination that the second temperature difference is equal to or higher than the second predetermined temperature is continued for the first determination time, there is a possibility that an abnormality (for example, disconnection of the wiring portion 32 of the temperature sensor 28, adhesion of foreign object to the detection unit 30, or the like) different from the abnormality in which water enters the connector 34 occurs. According to the above-described configuration, the control device 14 can determine that water is entering the connector 34 and can determine that the above-described different abnormality has occurred.
In addition, the control device 14 executes a process (S34) of counting the number of times of establishment N in which the sudden temperature change condition is repeatedly established at intervals within the second determination time, and a process (S38) of determining that water enters the connector 34 when the number of times of establishment N reaches a predetermined number of times (YES by S36). Further, the control device 14 executes a process (S42) of clearing the number of times of establishment N when the sudden temperature-change determination is not satisfied for the second determination period (YES in S40) prior to the number of times of establishment N reaching a predetermined number of times.
According to the above configuration, the control device 14 clears the number of times of establishment N when the temperature sudden change determination is not satisfied for the second determination time. According to such a configuration, it is possible to more accurately determine that water is entering into the connector 34 as compared with a configuration in which the number of times of establishment N is not cleared.
Further, the control device 14, when the temperature rapid change condition is established, and the first temperature difference is more than the third predetermined temperature (in S32 of
The amount of variation in the detected temperature varies depending on the type of foreign object entering the connector 34. According to the above configuration, the control device 14 can appropriately determine the type of the foreign object that has entered the connector 34 based on the first temperature difference. In particular, in the present embodiment, the control device 14 can specify whether the foreign object that has entered the connector 34 is water or metal.
Although the specific examples disclosed by the present disclosure have been described in detail above, these are merely examples and do not limit the scope of claims. The techniques described in the claims include various modifications and alternations of the specific example illustrated above. Modifications of the above-described embodiment are listed below.
S26 can be omitted from S10 of
S42 of
The “temperature sensor” is not limited to a sensor for detecting the temperature of the lubricating liquid, and may be a sensor for detecting the temperature of the high-voltage cable or the low-voltage cable of electrified vehicle.
The “vehicle” is not limited to an electrified vehicle, and may be an engine vehicle, a hybrid electric vehicle, fuel cell electric vehicle, a hydrogen-engine vehicle, or the like.
The processing of
The third predetermined temperature may be, for example, a threshold value for determining whether a foreign object that has entered the connector 34 is a resin or water.
The control device 14 may change the upper limit of the output value of the electric motor 20 only when the first abnormality flag becomes “ON” without changing the upper limit of the output value of the electric motor 20 and the second abnormality flag becomes “ON”. In other words, the control device 14 may switch the content (control mode or the like) of the process to be applied between the case where the first abnormality flag becomes “ON” and the case where the second abnormality flag becomes “ON”.
The technical elements described in the present specification or drawings exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the techniques illustrated in the present specification or drawings can achieve a plurality of objectives at the same time, and achieving one of the objectives itself has technical usefulness.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2023-140232 | Aug 2023 | JP | national |
| 2023-173683 | Oct 2023 | JP | national |
