CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to Japanese Patent Application No. 2020-109012 filed on Jun. 24, 2020, incorporated herein by reference in its entirety.

BACKGROUND

1. Technical Field

The present disclosure relates to a fault evaluation device for an automatic transmission, a fault evaluation method for an automatic transmission, and a non-transitory storage medium that stores a fault evaluation program for an automatic transmission.

2. Description of Related Art

WO 2012/111192 describes a vehicle including an evaluation device that evaluates a shifting shock in an automatic transmission. The evaluation device acquires acceleration from an acceleration sensor. The evaluation device evaluates a shifting shock in the automatic transmission based on transition in the acceleration from the start until the completion of shifting of the automatic transmission.

SUMMARY

The magnitude of a shifting shock in the automatic transmission may vary in accordance with not only the presence or absence of a fault of the automatic transmission but also other various factors. Therefore, even when the evaluation device described in WO 2012/111192 evaluates a shifting shock as being large, there is a considerable possibility that the large shifting shock is not due to a fault of the automatic transmission. That is, the evaluation device described in WO 2012/111192 has room for improvement for the evaluation of the presence or absence of a failure of an automatic transmission.

A first aspect of the present disclosure provides a fault evaluation device for an automatic transmission, the fault evaluation device evaluating a fault of the automatic transmission, and the fault evaluation device being used for a vehicle having the automatic transmission and a control device configured to execute a learning process for correcting a target pressure for oil to be supplied to the automatic transmission such that variations in acceleration of the vehicle during shifting of the automatic transmission are small. The fault evaluation device includes a processor and a memory. The memory stores mapping data that prescribe mapping. The processor is configured to output an output variable, which is an evaluation value that indicates presence or absence of the fault of the automatic transmission, when an input variable is input. The mapping includes, as the input variable, an acceleration variable, which is a variable that indicates the acceleration of the vehicle during shifting of the automatic transmission, and a learning progress variable, which is a variable that indicates a status of progress of learning in the learning process. The processor is configured to execute an acquisition process, which is a process to acquire the input variable, and a calculation process, which is a process to calculate a value of the output variable by inputting the input variable acquired through the acquisition process to the mapping.

With the configuration described above, the processor outputs an output variable, which is an evaluation value that indicates the presence or absence of the fault, in consideration of not only the acceleration of the vehicle during shifting of the automatic transmission but also the status of progress of the learning process for the target pressure for oil. Thus, an evaluation value indicating that no fault is caused in the automatic transmission can be output even when the acceleration during shifting becomes large because the learning process has not fully progressed yet, for example. That is, with the configuration described above, the presence or absence of the fault of the automatic transmission can be evaluated accurately irrespective of the status of progress of the learning process.

In the aspect described above, the learning progress variable may be a variable that takes a first value when the learning in the learning process has converged, and that takes a second value, which is different from the first value, when the learning in the learning process has not converged.

With the configuration described above, it is possible to obtain an evaluation value determined in consideration of whether learning has converged and the variations in the acceleration during shifting are relatively large or learning has not converged and the variations in the acceleration during shifting are relatively large. Thus, the fault of the automatic transmission can be evaluated accurately.

In the aspect described above, the learning progress variable may be a variable that indicates the number of times of execution of the learning process since the automatic transmission was mounted on the vehicle. In the above configuration, the number of times of execution of the learning process, which is a value strongly correlated with the degree of progress of the learning process, is input as an input variable. Therefore, an evaluation value that accurately reflects the degree of progress of the learning process can be obtained.

In the aspect described above, the learning progress variable may be a travel distance of the vehicle that has been traveled since the automatic transmission was mounted on the vehicle. In the above configuration, the travel distance of the vehicle, which is a value strongly correlated with the degree of progress of the learning process, is input as an input variable. Therefore, an evaluation value that accurately reflects the progress of the learning process can be obtained.

In the aspect described above, the target pressure may be calculated by adding or multiplying a learning correction value and a reference pressure which is a pressure of oil at a time when the learning process has not been performed yet; the learning process may be a process to calculate the learning correction value such that the variations in the acceleration of the vehicle during shifting of the automatic transmission are small; and the mapping may include the learning correction value as the input variable.

In the aspect described above, the absolute value of the learning correction value tends to be small when degradation etc. of the automatic transmission has not progressed, and to be large when degradation etc. of the automatic transmission has progressed. The presence or absence of the fault of the automatic transmission can be evaluated accurately by inputting a value that may reflect degradation etc. of the automatic transmission in this manner.

In the aspect described above, the automatic transmission may include a plurality of engagement elements and a plurality of gear stages operated by the engagement elements; and the mapping may include, as the input variable, a shifting type variable which indicates a type of the gear stages before and after shifting of the automatic transmission.

In the aspect described above, the ease of variation in the acceleration during shifting differs in accordance with the type of gear stages before and after shifting of the automatic transmission. With the configuration described above, the input variable includes a shifting type variable which indicates the type of gear stages before and after shifting of the automatic transmission, and thus the fault can be evaluated accurately in accordance with the type of gear stages.

In the aspect described above, the automatic transmission may include the engagement elements and the gear stages operated by the engagement elements; and the mapping may include, as the input variable, a variable indicating the number of times of shifting which indicates the number of times of shifting made since the automatic transmission was mounted on the vehicle, the number of times of shifting being made to one of the gear stages after shifting of the automatic transmission.

In the above aspect, the number of times of shifting made to the one of the gear stages after shifting of the automatic transmission, which is a value strongly correlated with the degree of wear of the automatic transmission, is input as an input variable. The presence or absence of the fault of the automatic transmission can be evaluated accurately by inputting a value that may reflect the degree of wear of the automatic transmission in this manner.

In the aspect described above, the automatic transmission may include the engagement elements and the gear stages operated by the engagement elements; and the mapping may include, as the input variable, a variable indicating the number of times of engagement which indicates the number of times of engagement made by the engagement elements since the automatic transmission was mounted on the vehicle, the number of times of engagement being made by an engagement element, among the engagement elements, that is engaged to establish one of the gear stages after shifting of the automatic transmission.

In the above configuration, the number of times of engagement made by the engagement element that is engaged to establish the one of the gear stages after shifting of the automatic transmission, which is a value strongly correlated with the degree of wear of the automatic transmission, is input as an input variable. The presence or absence of the fault of the automatic transmission can be evaluated accurately by inputting a value that may reflect the degree of wear of the automatic transmission in this manner.

In the aspect described above, the mapping may include, as the input variable, an accelerator variable which indicates an amount of operation of an accelerator pedal during shifting of the automatic transmission. In the above configuration, the variations in the acceleration during shifting of the automatic transmission differ, depending on the amount of operation of the accelerator pedal, even if the other conditions are the same. With the configuration described above, a value that indicates the amount of operation of the accelerator pedal is input, and thus an evaluation value that reflects the amount of operation of the accelerator pedal can be obtained.

A second aspect of the present disclosure provides a fault evaluation device for an automatic transmission, the fault evaluation device evaluating a fault of the automatic transmission, and the fault evaluation device being used for a vehicle having the automatic transmission and a control device configured to execute a learning process for correcting a target pressure for oil to be supplied to the automatic transmission such that variations in acceleration of the vehicle during shifting of the automatic transmission are small. The fault evaluation device includes a processor and a memory. The memory stores mapping data that prescribe first mapping and second mapping. The processor is configured to output an output variable, which is an evaluation value that indicates presence or absence of the fault of the automatic transmission, when a plurality of input variables is input. The first mapping and the second mapping includes, as one of the input variables, an acceleration variable which is a variable that indicates the acceleration of the vehicle during shifting of the automatic transmission; the first mapping is trained mapping that has been trained through machine learning on condition that a learning progress variable, which is a variable that indicates a status of progress of learning in the learning process, is within a first range; the second mapping is trained mapping that has been trained through machine learning on condition that the learning progress variable is within a second range which is different from the first range; and the processor is configured to execute an acquisition process, which is a process to acquire the input variables and the learning progress variable, a first calculation process to calculate a value of the output variable by inputting the input variables acquired through the acquisition process to the first mapping when the learning progress variable acquired through the acquisition process is within the first range, and a second calculation process to calculate the value of the output variable by inputting the input variables acquired through the acquisition process to the second mapping when the learning progress variable acquired through the acquisition process is within the second range.

With the configuration described above, one of the first mapping and the second mapping is selectively used in accordance with the learning progress variable which is a variable that indicates the status of progress of learning in the learning process. Consequently, an appropriate value can be output as an output variable which is an evaluation value that indicates the presence or absence of the fault, irrespective of the status of progress of the learning process. That is, with the configuration described above, the presence or absence of the fault of the automatic transmission can be evaluated accurately irrespective of the status of progress of the learning process.

A third aspect of the present disclosure provides a fault evaluation method for an automatic transmission, the fault evaluation method being used to evaluate a fault of the automatic transmission, and the fault evaluation method being used for a vehicle having the automatic transmission and a control device configured to execute a learning process for correcting a target pressure for oil to be supplied to the automatic transmission such that variations in acceleration of the vehicle during shifting of the automatic transmission are small. The fault evaluation method is executed by a fault evaluation device. The fault evaluation device includes a processor and a memory. The memory stores mapping data that prescribe mapping. The processor is configured to output an output variable, which is an evaluation value that indicates presence or absence of the fault of the automatic transmission, when an input variable is input. The fault evaluation method includes calculating a value of the output variable by inputting, as the input variable, an acceleration variable, which is a variable that indicates the acceleration of the vehicle during shifting of the automatic transmission, and a learning progress variable, which is a variable that indicates a status of progress of learning in the learning process, to the fault evaluation device.

With the configuration described above, the processor outputs an output variable, which is an evaluation value that indicates the presence or absence of the fault, in consideration of not only the acceleration of the vehicle during shifting of the automatic transmission but also the status of progress of the learning process for the target pressure for oil. Thus, an evaluation value indicating that no fault is caused in the automatic transmission can be output even when the acceleration during shifting becomes large because the learning process has not fully progressed yet, for example. That is, with the configuration described above, the presence or absence of the fault of the automatic transmission can be evaluated accurately irrespective of the status of progress of the learning process.

A fourth aspect of the present disclosure provides a fault evaluation method for an automatic transmission, the fault evaluation method being used to evaluate a fault of the automatic transmission, and the fault evaluation method being used for a vehicle having the automatic transmission and a control device configured to execute a learning process for correcting a target pressure for oil to be supplied to the automatic transmission such that variations in acceleration of the vehicle during shifting of the automatic transmission are small. The fault evaluation method is executed by a fault evaluation device. The fault evaluation device includes a processor and a memory. The memory stores mapping data that prescribe first mapping and second mapping. The processor is configured to output an output variable, which is an evaluation value that indicates presence or absence of the fault of the automatic transmission, when a plurality of input variables is input. The first mapping and the second mapping include, as one of the input variables, an acceleration variable which is a variable that indicates the acceleration of the vehicle during shifting of the automatic transmission. The first mapping is trained mapping that has been trained through machine learning on condition that a learning progress variable, which is a variable that indicates a status of progress of learning in the learning process, is within a first range. The second mapping is trained mapping that has been trained through machine learning on condition that the learning progress variable is within a second range which is different from the first range. The fault evaluation method includes: inputting, as the input variables, the acceleration variable and the learning progress variable to the fault evaluation device; and calculating a value of the output variable by inputting the input variables to the first mapping when the learning progress variable is within the first range, and calculating the value of the output variable by inputting the input variables to the second mapping when the learning progress variable is within the second range.

With the configuration described above, one of the first mapping and the second mapping is selectively used in accordance with the learning progress variable which is a variable that indicates the status of progress of learning in the learning process. Consequently, an appropriate value can be output as an output variable which is an evaluation value that indicates the presence or absence of the fault, irrespective of the status of progress of the learning process. That is, with the configuration described above, the presence or absence of the fault of the automatic transmission can be evaluated accurately irrespective of the status of progress of the learning process.

A fifth aspect of the present disclosure provides a non-transitory storage medium that stores a fault evaluation program for an automatic transmission, the fault evaluation program being configured to cause a computer to operate as a fault evaluation device that evaluates a fault of the automatic transmission. The fault evaluation program is used for a vehicle having the automatic transmission and a control device configured to execute a learning process for correcting a target pressure for oil to be supplied to the automatic transmission such that variations in acceleration of the vehicle during shifting of the automatic transmission are small. The fault evaluation program has mapping data that prescribe mapping. The mapping includes, as an input variable, an acceleration variable, which is a variable that indicates the acceleration of the vehicle during shifting of the automatic transmission, and a learning progress variable, which is a variable that indicates a status of progress of learning in the learning process. The fault evaluation program is configured to cause the computer to execute a function to acquire the input variable and a function to calculate a value of an output variable, which is an evaluation value that indicates presence or absence of the fault of the automatic transmission, by inputting the acquired input variable to the mapping.

With the configuration described above, the processor outputs an output variable, which is an evaluation value that indicates the presence or absence of the fault, in consideration of not only the acceleration of the vehicle during shifting of the automatic transmission but also the status of progress of the learning process for the target pressure for oil. Thus, an evaluation value indicating that no fault is caused in the automatic transmission can be output even when the acceleration during shifting becomes large because the learning process has not fully progressed yet, for example. That is, with the configuration described above, the presence or absence of the fault of the automatic transmission can be evaluated accurately irrespective of the status of progress of the learning process.

A sixth aspect of the present disclosure provides a non-transitory storage medium that stores a fault evaluation program for an automatic transmission, the fault evaluation program being configured to cause a computer to operate as a fault evaluation device that evaluates a fault of the automatic transmission. The fault evaluation program is used for a vehicle having the automatic transmission and a control device configured to execute a learning process for correcting a target pressure for oil to be supplied to the automatic transmission such that variations in acceleration of the vehicle during shifting of the automatic transmission are small. The fault evaluation program has mapping data that prescribe first mapping and second mapping. The first mapping and the second mapping include, as one of a plurality of input variables, an acceleration variable which is a variable that indicates the acceleration of the vehicle during shifting of the automatic transmission. The first mapping is trained mapping that has been trained through machine learning on condition that a learning progress variable, which is a variable that indicates a status of progress of learning in the learning process, is within a first range. The second mapping is trained mapping that has been trained through machine learning on condition that the learning progress variable is within a second range which is different from the first range. The fault evaluation program is configured to cause the computer to execute a function to acquire the input variables and the learning progress variable, a function to calculate a value of an output variable, which is an evaluation value that indicates presence or absence of the fault of the automatic transmission, by inputting the acquired input variables to the first mapping when the acquired learning progress variable is within the first range, and a function to calculate the value of the output variable by inputting the acquired input variables to the second mapping when the acquired learning progress variable is within the second range.

With the configuration described above, one of the first mapping and the second mapping is selectively used in accordance with the learning progress variable which is a variable that indicates the status of progress of learning in the learning process. Consequently, an appropriate value can be output as an output variable which is an evaluation value that indicates the presence or absence of the fault, irrespective of the status of progress of the learning process. That is, with the configuration described above, the presence or absence of the fault of the automatic transmission can be evaluated accurately irrespective of the status of progress of the learning process.

