JPH1063582A - Controller for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To keep fault information and learning information of an automatic transmission to be nonvolatile and reliable even in a state where a power source is turned off. SOLUTION: Fault information and learning information of the automatic transmission are held by writing in EEPROM 18. As stored contents in EEPROM 18 is easily volatile when the number of writing times exceeds a limit value of several ten thousand times, writing is prohibited at the point of time when the number of writing times amounts to ten thousand times to fix the stored contents at the time. At the time of setting three sets of a data area and a number of times area to EEPROM 18 and using them in order, thirty thousand of writing becomes possible and written information for three newest times can be read from EEPROM 18.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for a vehicle which uses a memory element having a limited number of write operations to hold failure information and learning information in a nonvolatile manner even in a power-off state.

[0002]

2. Description of the Related Art A vehicle control device has been put to practical use in which failure information formed by detecting a failure of each part of a vehicle, constant information formed by learning control of an automatic transmission, and the like are written in a memory element and held. . Since such information needs to be held in a nonvolatile manner even when the key switch of the automobile is turned off and the power is cut off, a normal RAM element can be backed up by a lithium battery, or a rewritable ROM can be used as a memory element. It is necessary to use elements, so-called EEPROMs.

[0003] JP-A-61-169332 discloses E
A vehicle control device is shown in which an EPROM is used to convert the content of the failure into data and write the failure every time a failure occurs in the automatic transmission.

[0004]

SUMMARY OF THE INVENTION Rewritable ROM
In the element, the stored contents of the bit are easily volatilized as the number of times of writing increases, and the reliability of the stored contents is lost when the number of times exceeds a predetermined limit number such as 10,000 to 100,000 times. If a failure judgment is made based on the erroneous stored contents of the rewritable ROM element, there is a possibility that the repair may be erroneous. Further, when learning control is used for hydraulic pressure control during shifting of the automatic transmission, shift shock may increase if hydraulic control during shifting is performed based on incorrect memory contents.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a vehicle control device capable of executing appropriate failure judgment and accurate learning control while ensuring the reliability of the stored contents of a rewritable ROM element.

[0006]

According to a first aspect of the present invention, there is provided a memory element capable of rewriting storage contents and holding nonvolatile data even in a power-off state, and writing information is acquired through control of a vehicle, and the memory element is stored in the memory element. A control circuit for writing a predetermined amount of data, wherein when the number of times of writing in the same area of the memory element reaches a predetermined value, writing to that area is prohibited.

According to a second aspect of the present invention, in the configuration of the first aspect, a data area for holding the data and a count area for holding the number of times of writing are set in the memory element, and the control device stores the data in the memory. Each time writing to the data area is performed, writing is performed to change the recorded content of the count area by one, and when the recorded content of the count area reaches a predetermined number, writing to the data area is prohibited.

According to a third aspect of the present invention, in the configuration of the second aspect, a plurality of sets of the data area and the count area are set in the memory element, and the control circuit determines that the recorded content in the set count area is a predetermined value. , The writing of the data is started in another unused set.

According to a fourth aspect of the present invention, in the configuration of the second aspect, a plurality of sets of the data area and the count area are set in the memory element, and the control circuit stores a plurality of sets of the data area and the count area. The data is written in order.

According to a fifth aspect of the present invention, in the configuration of the first to fourth aspects, the data is at least one of failure information of the automatic transmission and a learning constant of automatic transmission control.

[0011]

According to the first aspect of the present invention, the stored contents written in the memory element can be held in a nonvolatile manner even in a power-off state, so that control and judgment can be made by referring to the stored contents when the power is supplied again or at a later date. To When the number of times of writing in the same area of the memory element exceeds a predetermined value, the reliability of the stored contents is lost. Therefore, when the number of times of writing reaches the predetermined value, writing in the same area is prohibited, and writing is performed last. The stored contents are kept.

In the vehicle control device according to the second aspect, the number of times of writing in the data area is equal to the number of times of counting in the number of times area. The number of times of writing in the data area is evaluated with reference to the number of times of writing in the number of times area of the memory element. When the number of times of writing in the number-of-times area reaches a predetermined value, the number of times of writing in the data area also reaches the predetermined value, and the storage contents are fixed in both areas, and thereafter the reliability of the storage contents is kept constant.

According to the third aspect of the present invention, by using a plurality of sets of the data area and the number-of-times area, the number of times of writing the number of times of writing to the bit of the memory element can be plural times. When the number of times of writing in one set reaches a predetermined value, writing in another unused set is started.

According to the vehicle control device of the fourth aspect, by using a plurality of sets of the data area and the number-of-times area, it is possible to write the number of times of the number of times of writing permitted for the bit of the memory element. Since writing is performed by using a plurality of sets sequentially, the memory element always holds the latest plurality of data with a certain level of reliability.

According to a fifth aspect of the present invention, there is provided a vehicle control apparatus in which failure information rewritten each time an automatic transmission failure occurs or a learning constant for control optimized in a control process of automatic transmission control is stored in a memory. Written to the element.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment will be described with reference to FIGS. As shown in FIG. 1, the automatic transmission control unit 10 includes an input circuit 12, an output circuit 13, and three types of memory elements around a CPU (arithmetic element) 15. The three types of memory elements allow free writing, but lose their stored contents when the power is turned off.
AM16, ROM 17 in which the stored contents cannot be changed, and stored contents even when the power is turned off, but EEPROM18 in which the stored contents are not guaranteed if the number of times of writing exceeds 10,000 times.
It is. The power supply circuit 11 forms a power supply voltage of 5 V from a DC voltage of 12 V supplied from a vehicle-mounted battery 21 through a key switch 22, and generates an arithmetic element 15, an input circuit 12, an output circuit 13, a RAM 16, a ROM 17,
It is supplied to the EPROM 18.

An operation unit 23, an engine 24, and an automatic transmission 25 are connected to the input circuit 12. Operation unit 23
The automatic transmission 25 receives output signals from various sensors, select switches, and the like. The automatic transmission 25 changes the ON / OFF combination of the solenoids A and B (not shown) to switch the gear position. The signal input for detecting the abnormality of the solenoids A and B is also input to the input circuit 1.
2 are connected. The input circuit 12 converts these various input signals into digital signals suitable for the CPU 15 and inputs the digital signals to the CPU 15. The output circuit 13 is connected to the automatic transmission 25 and the warning unit 26, and forms a signal output adapted to a connection destination from a digital signal output by the CPU 15.

The CPU 15 controls a plurality of solenoids and actuators of the automatic transmission 25 through the output circuit 13. The CPU 15 forms data including the failure information (only the failure location) and the learning constant in the EEPROM 18 when the failure of the automatic transmission 25 is detected and when the learning constant is changed through the learning control of the automatic transmission 25. Write. When the number of times of writing in the EEPROM 18 reaches a predetermined limit value, the CPU 15 displays, through the warning unit 26, a character display indicating that the failure content and the learning constant are not currently updated.

As shown in FIG. 2A, an EEPROM
18, a 30-byte data area E1 and a 2-byte count area F1 are set. Each time the storage content of the data area E1 is rewritten once, the storage content (the number of times N1) of the count area F1 is increased by one, and when it reaches 10,000, rewriting of the data area E1 is prohibited.
It is held in the 999th write state. The data written in the data area E1 is configured as shown in FIG. The total is 30 bytes, the first two bytes are failure information, and the next 24 bytes are learning constants.

In the first two bytes, 16 bits, bit B1
Is solenoid A, bit B2 is solenoid B, bit B
Reference numeral 3 corresponds to a throttle sensor. When a failure such as a disconnection or a short circuit is detected, data is set in which a bit corresponding to a failed portion is set to 1 and a bit corresponding to a normal portion is set to 0. In the 24 bytes following the first 2 bytes, a set value of the line pressure (a control amount of the line pressure solenoid) for each combination of the type of shift, the throttle opening, and the temperature range is arranged. That is, 24 types of conditions are selected from a combination of first-gear, second-gear, second-gear and third-gear shift types and a temperature range of eight stages of throttle opening, low temperature, and normal temperature. Byte control amount is set. The automatic transmission control unit 10 measures the shift time each time a shift is executed by the automatic transmission 25, and determines that the set value of the line pressure is inappropriate when the shift time departs from a predetermined reference value. Then, the control amount corresponding to the condition at that time is changed.

The automatic transmission control unit 10 includes:
The automatic transmission 25 is controlled in accordance with the flowchart shown in FIG. 3, and the contents stored in the EEPROM 18 are rewritten. In step 111, normal control of the automatic transmission 25 is executed. The optimum gear position is selected according to the selected opening position of the throttle opening of the engine 25 and the vehicle speed, and the automatic transmission 25 is selected according to the selected gear position.
The ON / OFF combination of the solenoids A and B for shifting is switched.

In the shifting process, the line pressure is changed in association with the ON / OFF of the solenoids A and B for shifting. In the speed change process, the line pressure of the automatic transmission 25 is reduced below a normal value to allow slip on the friction surface of the engagement element (clutch, brake) and absorb the speed change shock.
The control amount for setting the line pressure in the shift process is adjusted to the current value by repeatedly updating from an initial value by learning control. The learning control of the line pressure cancels out the increase in the shift time due to the wear of the friction surface, and enables the shift with the same responsiveness as a new vehicle without increasing the shift shock. The solenoid of the automatic transmission 25 is provided with a dedicated fault detection circuit for detecting a fault such as a disconnection or a short circuit. The CPU 15 determines the failure of the solenoid from the output of the failure detection circuit. With respect to some other sensors, the CPU 15 determines a failure by detecting an abnormal output value contrary to the situation.

In step 112, it is determined whether or not the number of times N1 of writing set in the number-of-times area F1 of the EEPROM 18 has reached 10,000. If it is less than 10,000 times, it is determined in step 113 whether or not the reset has been performed. If the number of times reaches 10,000, a warning is displayed through the warning unit 26 in step 123. The reset in step 113 is an operation in which the person in charge forcibly erases the storage contents of the failed part when the repair is completed at the repair shop. When the reset is performed, the process proceeds to step 120, where data corresponding to the reset is formed. In step 120, all 16 bits of the failure information are set to 0, and write data without changing the learning constant is formed. If it does not correspond to the reset, the routine proceeds to step 114, where the data area E1 of the EEPROM 18 is read.

In step 115, it is determined whether a new failure has been detected. If a failure point has been detected through the control of step 111, it is compared with the failure information of the data area E1 read in step 114. If no failure has been detected, or if a failure point already recorded as a failure point has been detected again, the process proceeds to step 116. This is because it is not necessary to rewrite the failure information again if the failure information is already recorded. Step 1
At 16, it is determined whether or not the learning constant has been changed through the control of step 111. If the new fault is not detected and the learning constant is unchanged, the process proceeds to step 117 to determine whether or not the fault is resolved. If no failure has been detected at this time for the failure location read in step 114, it is determined that the failure location has returned to a normal state, and the process proceeds to step 119, where a 1 for the corresponding failure location has been replaced with 0, and Form the data. If a failure has been detected for the failure location read in step 114,
If there is no record of the failure location, the following flow is bypassed, and the EEPOM 18 is not written.

If it is determined in step 115 that a new fault has been detected, then in step 118, out of the 16 bits of fault information,
Write data is formed by changing the bit of the new fault location to 1. If it is determined in step 116 that the learning constant has been changed, in step 118, write data in which the old learning constant of the corresponding condition is replaced with a new learning constant is formed. The original value is copied as it is with respect to the faulty portion that remains faulty or the learning constant that does not change.

In step 121, steps 118, 1
The data formed by either of 19 and 120 is EEPR
The data is written to the data area E1 of the OM 18. Step 1
At 22, a value obtained by adding 1 to the number of times N1 read from the number-of-times area F1 of the EEPROM 18 is newly added to the number-of-times area F1.
Is written to.

According to the automatic transmission control unit 10 of the first embodiment, even if the key switch 22 is turned off,
Failure point of the automatic transmission 25 and its control system is EEP
Since the information is stored in the ROM 18 in a non-volatile manner, it can be used as powerful reference information for specifying a failed portion, and the efficiency and reliability of repair and maintenance are improved. Since the learning constant used for the line pressure control at the time of shifting is held in the same manner, the replacement of the battery 21 and the automatic transmission control unit 1
Even if the vehicle is detached and repaired, the continuity of the operational feeling of the vehicle is ensured, and the driver does not feel uncomfortable. In addition, the fault information is rewritten only in the case of a new fault and when the fault is cleared, and is not rewritten when the same fault is detected continuously. The number of times of replacement is saved, and the EEPROM 18 can be used for a long time. When the number of rewrites N1 reaches 10,000, rewriting in the data area E1 is prohibited.
The recorded contents of the data area E1 are not changed, so that it does not take too much time to specify the failure location, and the line pressure control does not become inappropriate.

The second embodiment will be described with reference to FIGS. In the second embodiment, the write data shown in FIG. 2B is used as it is.
The manner of writing to the PROM 18 is different. FIG.
As shown in FIG. 2, in the second embodiment,
Three data areas E1 to E3 and three count areas F1 to F
Set 3. Referring to the number of times of writing N1, N2, N3 read from the number of times area F1 to F3, the data area E
Writing is performed 10,000 times in the order of 1, E2, and E3. When the number of writes N1 in the data area E1 reaches 10,000, the storage location of the fault location and the learning constant is changed to the unused data area E2. When the number of writes N2 reaches 10,000 in the data area E2, the writing in the data area E3 is started. When the number of writes N3 in the data area E3 reaches 10,000, both the failure information and the learning constant remain fixed at the contents stored at that time.

In the second embodiment, the recording of the fault location and the learning control of the line pressure are performed according to the procedure shown in FIG. In step 211, the control of the automatic transmission 25 including the learning control of the line pressure and the detection of the failure location is executed in the same manner as in step 111 of FIG. In step 212, it is determined whether or not the number N1 read from the number area F1 has reached 10,000. If the number of times N1 is less than 10,000 times, the process proceeds to step 221, where the data area E1 and the number of times area F
One set is selected. If the number N1 is 10,000, the data area E1 is not appropriate as the current recording location.
Proceed to step 213. In step 213, it is determined whether or not the number N2 read from the number area F2 is zero.
If the number N2 is 0, the process proceeds to step 214, where the stored contents of the data area E1 are copied to the data area E2 as they are. Since the recorded content of the data area E2 is read in the subsequent step 223, the stored content of the data area E1 is prepared for the first time.

If the count N2 is not 0, the process proceeds to step 215, where it is determined whether or not the count N2 read from the count area F2 is 10,000. If the number N2 is less than 10,000, the process proceeds to step 220, where the data area E is set as the current recording location.
A set of 2 and the number area F2 is selected. If the number N2 is 10,000, the process proceeds to step 216 because the data area E3 can be selected as the current recording location. Step 216
In, it is identified whether or not the number N3 read from the number region F3 is 0. If the number N3 is 0, the process proceeds to step 217, and the stored contents of the data area E2 are copied to the data area E3 as they are. In a later step 223, the data area E3
Of the data area E2 is prepared for the first time. In step 218, the number of times N3 is 1
Whether or not it is 10,000 times is identified. If the number N3 is less than 10,000, the process proceeds to step 219, where a set of the data area E3 and the number area F3 is selected as the current recording location. Number N3
Is 10,000 times, the process proceeds to step 232, and a warning display similar to that in step 123 of FIG. 3 is performed.

In step 222 and subsequent steps, step 212
Using one set of the data area and the number-of-times area selected through the processes of to 221, the failure information is recorded and the learning constant is updated. In step 222, it is identified whether or not the reset has been performed. If it has been reset, it is determined that the failed part has been repaired normally, and the process proceeds to step 229, where the data in which all the 16 bits of the failure information are set to 0 as in step 120 of the first embodiment. create. If it does not correspond to the reset, the process proceeds to step 223 to read the storage contents of the selected data area.

In step 224, it is determined whether a new failure has been detected. If a failure has been detected at a failure location that has not been recorded in the data area, the process proceeds to step 227, where the bit of the new failure location is set to 1 in the 16 bits of failure information.
The changed data is created. If it does not correspond to the new failure detection, the process proceeds to step 225. In step 225, it is determined whether or not the learning constant has been changed. If the learning constant has been changed, the process proceeds to step 227 to create data in which the old learning constant is replaced with the new learning constant.
If the learning constant is not changed, the process proceeds to step 226, where it is determined whether or not the failure has been resolved. If no failure is detected for the failure location read in step 223, step 2
Proceeding to step 28, data is generated in which 1 of the corresponding fault location is replaced with 0. If the failure point read in step 223 has been detected this time, or if there is no record of the failure point, steps 227 to 227 are performed.
The flow of 31 is bypassed and writing to the EEPROM 18 is not executed. In step 230, the created data is written to the EEPROM 18, and the storage content of the selected data area is updated. In step 231, a value obtained by adding 1 to the number of times read from the selected count area is newly written in the count area.

According to the second embodiment, it is possible to secure three times the number of times of writing as compared with 10,000 times of the first embodiment.

A third embodiment will be described with reference to FIG. In the third embodiment, three data areas E1, E2,
The processing of steps 212 to 221 shown in FIG. 5 is replaced with the processing shown in FIG. 6 by using E3 and the number-of-times regions F1, F2, and F3. That is, the storage contents are rewritten using the set of the data area E1 and the count area F1, the set of the data area E2 and the count area F2, and the set of the data area E3 and the count area F3 in order. To the frequency area F
When the number of times N3 reaches 10,000, the failure information and the learning constant are fixed.

Here, the description of the common configuration and processing described above is omitted, and each processing shown in FIG. 6 will be described.
In step 312, the number of times N3 read from the count area F3 is compared with the number of times N2 read from the count area F2. If the number N2 is larger than the number N3, the writing has been executed in the data area E2 last time, so the process proceeds to step 317, and the set of the data area E3 and the number area F3 is selected as the current recording location. If the number N3 is equal to the number N2, the process proceeds to step 313. In step 313, the number of times N1 and the number of times F
The number of times N2 read from step No. 2 is compared. If the number N1 is larger than the number N2, the writing has been executed in the data area E1 last time, so the process proceeds to step 316, and the set of the data area E2 and the number area F2 is selected as the current recording location. If the number N1 is equal to the number N2, the process proceeds to step 314.

At step 314, it is determined whether or not the number N3 is 10,000. If the number N3 is less than 10,000, the process proceeds to step 315, and the data area E1 is set as the current recording location.
Is selected. Data area E1, E
2, E3 are used in order to repeat the number of rewrites, and the number N
When 1 becomes 10,000 times, writing using the data area E2 is executed next time, and the number of times N2 becomes 10,000 times. Finally, the writing using the data area E3 is executed and the number of times N3
Has reached 10,000 times, the process proceeds from step 314 to step 232 next time to display a warning.

According to the control of the third embodiment, it is possible to secure three times the number of times of writing as compared with 10,000 times of the first embodiment. Then, by reading the stored contents of the data areas E1, E2, and E3, in addition to the latest failure information, failure information of the past two times immediately before the latest failure information can be obtained. It is also possible to accurately determine a contact failure or the like that is easy to be overlooked due to repeated determination of failure and failure elimination.

In the automatic transmission, the learning constant converges to a substantially constant value at a traveling distance of about 10,000 km from the new vehicle. For example, the learning constant is fixed when the number of writings reaches 10,000. Thereafter, only the failure information may be updated.
Then, when the friction plate of the automatic transmission is replaced, the updating of the learning constant may be started through a reset operation by a person in charge. As a result, a large recording area in which the same learning information has been repeatedly recorded after 10,000 times of writing can be allocated to recording of failure information. Further, an area for storing the failure information and an area for storing the learning constant may be provided separately, and a number-of-times area may be provided respectively. One data area is set for learning constants and rewriting is prohibited when the number of rewrites reaches 10,000, and five data areas are set for failure information and written in order, for a total of 50,000. It may be possible to write once.

In each of the above embodiments, the failure information and the learning constant are written in the EEPROM every time the write information is acquired. However, the present invention is not limited to this. May be. As a result, the number of times of rewriting is further reduced, and EE
The PROM can be used for a long time.

[0040]

According to the first aspect of the present invention, since the number of times of writing in the same area of the memory element does not exceed the predetermined value, the reliability of the storage content of that area is secured to a certain level or more.

According to the second aspect of the present invention, since the count area is provided in the same memory element for setting the data area, there is no need to provide a dedicated memory element for holding the write count in a nonvolatile manner even when the power is shut off.

According to the third aspect of the present invention, it is possible to execute writing many times as compared with the case where one set of a data area and a count area is provided.

According to the fourth aspect of the present invention, it is possible to execute writing many times as compared with the case where one set of a data area and a count area is provided. In addition, since the set of the data area and the count area is used in order, it is possible to obtain the latest write information at any time and write information for a plurality of times that goes back in the past, so that these write information can be compared and used effectively. Repair and maintenance can be performed accurately.

According to the fifth aspect of the present invention, the reliability of the failure location and the content of the failure read from the memory element can be secured to a certain level or more, so that the failure determination is not performed based on the wrong storage content different from the written content. I'm done. In addition, since the reliability of the learning constant read from the memory element can be maintained at a certain level or more, it is not necessary to control the automatic transmission according to an incorrect learning constant different from a value obtained through learning.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of the configuration and connection of an automatic transmission control unit.

FIG. 2 is an explanatory diagram of setting of a data area and a count area in a memory element.

FIG. 3 is a flowchart of control according to the first embodiment.

FIG. 4 is an explanatory diagram of setting of a data area and a count area in a memory element.

FIG. 5 is a flowchart of control according to a second embodiment.

FIG. 6 is a flowchart of control according to a third embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Automatic transmission control unit 11 Power supply circuit 12 Input circuit 13 Output circuit 15 CPU 16 RAM 17 ROM 18 EEPROM 21 Battery 22 Key switch 23 Operation part 24 Engine 25 Automatic transmission 26 Warning part B1, B2, B3 Bit E1, E2, E3 data area F1, F2, F3 count area

Claims (5)

[Claims] 1. A memory device having a rewritable storage content and capable of being held in a nonvolatile manner even in a power-off state, and a control circuit for obtaining write information through control of a vehicle and writing a predetermined amount of data into the memory device. A control device for a vehicle, wherein when the number of times of writing in the same area of the memory element reaches a predetermined value, writing to the area is prohibited. 2. A data area for holding the data and a count area for holding the number of times of writing are set in the memory element, and the control device records the number of times each time the data is written to the data area. 2. The vehicle control device according to claim 1, wherein writing is performed to change the content by 1, and writing to the data area is prohibited when the recorded content of the count area reaches a predetermined number. 3. A plurality of sets of the data area and the count area are set in the memory element, and the control circuit sets another unused set every time the recording content reaches a predetermined value in one set of the count area. 3. The vehicle control device according to claim 2, wherein the writing of the data is started. 4. A plurality of sets of the data area and the count area are set in the memory element, and the control circuit writes the data by sequentially using the plurality of sets of the data area and the count area. The vehicle control device according to claim 2, wherein 5. The vehicle control device according to claim 1, wherein the data is at least one of failure information of an automatic transmission and a learning constant of automatic transmission control.