JP2009115165A - Controller for automatic transmission - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a controller for automatic transmission which can prevent an increase in difference between a learning value stored in a volatile memory at an initial stage when the learning value does not converge and a learning value stored in a non-volatile memory, and also prevent a newest learning value stored in the volatile memory from being not written into the non-volatile memory. <P>SOLUTION: A CPU of an electronic controller calculates a learning value change amount Cg based on a new learning value Gn read from an SRAM and an existing learning value Gex read from an EEPROM (step S3), calculates a write enable change amount Cp based on a written number Nr (step S4) and writes the new learning value Gn into the EEPROM (step S6) when it is determined that the learning value change amount Cg is not less than the write enable change amount Cp (YES in step S5). <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a control device for an automatic transmission, and more particularly to a control device for an automatic transmission that writes a learned value in a shift control of an automatic transmission from a volatile memory to a nonvolatile memory.

  Generally, an electronic control device mounted on a vehicle controls an internal combustion engine and a transmission using data stored in an electrically writable volatile memory. The data stored in the volatile memory is sequentially updated by learning control that reflects past control results in order to compensate for individual differences in vehicles, changes with time, and the like. Here, in the volatile memory, when the power supply from the battery mounted on the vehicle is stopped, the data stored in the volatile memory, that is, the learning value is deleted. For this reason, the electronic control unit appropriately backs up the learning value from the volatile memory to the nonvolatile memory in which the memory contents are not erased even when there is no power supply, and the learning stored in the volatile memory. When the value is erased, the learned value can be restored from the nonvolatile memory.

Conventionally, this type of backup device is stored in the volatile memory when the difference between the learned value stored in the volatile memory and the learned value stored in the non-volatile memory is equal to or greater than a predetermined value. A learning value is written in a nonvolatile memory (see, for example, Patent Document 1).
JP 2006-293650 A

  However, in the apparatus described in Patent Document 1, the learning value converges when a predetermined value for determining whether or not the learning value stored in the volatile memory is written to the nonvolatile memory is set large. There is a problem that the difference between the learning value stored in the volatile memory and the learning value stored in the non-volatile memory becomes large at an initial stage where the memory is not used. On the other hand, when the predetermined value for determining whether or not the learning value stored in the volatile memory is to be written to the nonvolatile memory is set to a small value, the upper limit of the number of times of writing to the nonvolatile memory is reached. There is a problem that the time is shortened and the latest learning value stored in the volatile memory is not written in the nonvolatile memory.

  The present invention has been made to solve the above-described conventional problems, and the learning value stored in the volatile memory and the nonvolatile memory in the initial stage where the learning value has not converged. Provided is a control device for an automatic transmission that can prevent a difference from a learned value from increasing and prevent the latest learned value stored in a volatile memory from being written to a nonvolatile memory. For the purpose.

  In order to achieve the above object, a control apparatus for an automatic transmission according to the present invention includes (1) an electrically writable volatile memory and a nonvolatile memory, and engages a friction engagement element of the automatic transmission. In a control device for an automatic transmission that writes a learned value for correcting a hydraulic pressure command value from the volatile memory to the nonvolatile memory, the learned value stored in the volatile memory and the nonvolatile memory Difference calculating means for calculating a difference from the stored learning value, write permission change amount calculating means for calculating a write permission change amount that increases as the number of times of writing to the nonvolatile memory increases, and the difference calculation Difference determining means for determining whether or not the difference calculated by the means is greater than or equal to the write permission change amount calculated by the write permission change amount calculating means; If the difference is determined to be write enable change amount or more, and has a configuration including a writing means for writing the learning value stored in the volatile memory to the nonvolatile memory.

  With this configuration, the difference between the learning value stored in the volatile memory and the learning value stored in the nonvolatile memory is greater than or equal to the write permission change amount that increases as the number of writes to the nonvolatile memory increases. In some cases, the learning value stored in the volatile memory is written into the non-volatile memory, so the learning value stored in the volatile memory and the non-volatile memory are stored in the initial stage when the learning value has not converged. It is possible to prevent the difference from the learning value from becoming large. Furthermore, since the time until the upper limit value of the number of times of writing to the nonvolatile memory is increased, it is possible to prevent the latest learning value stored in the volatile memory from being written to the nonvolatile memory.

  Further, the automatic transmission control device according to the present invention is the automatic transmission control device according to (1), wherein (2) the difference determination means continuously determines that the difference is not greater than the write permission change amount. A write non-permission count unit that counts the number of write non-permissions that represents the number of times determined by the above, and when the difference determination unit determines that the difference is not greater than or equal to the write permission change amount, And a write non-permission count determination unit that determines whether or not the counted number of write non-permissions is equal to or greater than a predetermined number. When it is determined that the permitted number is equal to or greater than a predetermined number, the learning value stored in the volatile memory is written in the nonvolatile memory. .

  With this configuration, when the learning value is not written from the volatile memory to the nonvolatile memory until the predetermined number of times is written, the learning value stored in the volatile memory is written to the nonvolatile memory. Therefore, the learning value converged more accurately can be written in the nonvolatile memory.

  According to the present invention, it is possible to prevent the difference between the learning value stored in the volatile memory and the learning value stored in the nonvolatile memory from becoming large at the initial stage where the learning value has not converged. Thus, it is possible to provide a control device for an automatic transmission that can prevent the latest learned value stored in the volatile memory from being written to the nonvolatile memory.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a skeleton diagram showing a configuration of a vehicle drive device according to a first embodiment of the present invention.
First, the configuration will be described.

  As shown in FIG. 1, the vehicle drive device is mounted on a vehicle such as an automobile, and includes an engine 11 and an automatic transmission 1. The engine 11 is a traveling power source constituted by an internal combustion engine, and the output of the engine 11 is input to a transmission mechanism 13 via a torque converter 12 as a fluid power transmission device, and a differential gear device (not shown). And it is transmitted to a drive wheel via an axle. The automatic transmission 1 includes a torque converter 12 and a transmission mechanism 13.

  The torque converter 12 includes a pump impeller 21 connected to the engine 11, a turbine impeller 23 connected to the input shaft 22 of the speed change mechanism 13, and a stator blade that is prevented from rotating in one direction by a one-way clutch 24. A vehicle 25 is provided, and power is transmitted between the pump impeller 21 and the turbine impeller 23 via a fluid. Furthermore, the torque converter 12 includes a lockup clutch 26 for directly connecting the pump impeller 21 and the turbine impeller 23. Further, the pump impeller 21 is provided with a mechanical oil pump 27 that generates hydraulic pressure for controlling the speed change of the transmission mechanism 13 and hydraulic pressure for supplying lubricating oil to each part.

  The speed change mechanism 13 is a planetary gear type speed change mechanism including a double pinion type first planetary gear device 28, a single pinion type second planetary gear device 29, and a third planetary gear device 30. The sun gear S1 of the first planetary gear device 28 is selectively connected to the input shaft 22 via the clutch C3, and is selectively connected to the housing 31 via the one-way clutch F2 and the brake B3. The rotation in the direction opposite to the rotation direction of the input shaft 22 is prevented.

  The carrier CA1 of the first planetary gear unit 28 is selectively connected to the housing 31 via the brake B1, and is always prevented from rotating in the reverse direction by the one-way clutch F1 provided in parallel with the brake B1. It has become so. The ring gear R1 of the first planetary gear device 28 is integrally connected to the ring gear R2 of the second planetary gear device 29, and is selectively connected to the housing 31 via the brake B2. The sun gear S2 of the second planetary gear device 29 is integrally connected to the sun gear S3 of the third planetary gear device 30, is selectively connected to the input shaft 22 via the clutch C4, and the one-way clutch F4. And is selectively connected to the input shaft 22 via the clutch C1, and is prevented from rotating in the reverse direction.

  The carrier CA2 of the second planetary gear device 29 is integrally connected to the ring gear R3 of the third planetary gear device 30 and is selectively connected to the input shaft 22 via the clutch C2 and via the brake B4. Thus, it is selectively connected to the housing 31 and is further prevented from rotating in the reverse direction by a one-way clutch F3 provided in parallel with the brake B4. The carrier CA3 of the third planetary gear device 30 is integrally connected to the output shaft 32.

  The clutches C1 to C4 and the brakes B1 to B4 (hereinafter simply referred to as the clutch C and the brake B unless otherwise distinguished) are hydraulic friction engagement devices that are controlled by a hydraulic actuator such as a multi-plate clutch or brake. . In addition, the clutch C and the brake B are switched when the hydraulic circuit is switched by the solenoid valves Sol1 to Sol5 of the hydraulic control circuit 59 (see FIG. 3) and the excitation and non-excitation of the linear solenoid valves SL1 and SL2 and a manual valve (not shown). For example, as shown in FIG. 2, the engaged and disengaged states are switched, and six forward shift stages (1st to 6th) and one reverse shift stage according to the operation position (position) of the shift lever 58 (see FIG. 3). (Rev) is established.

FIG. 2 is a diagram showing a relationship between a combination of operations of a plurality of hydraulic friction engagement devices in the automatic transmission according to the first embodiment of the present invention and a shift stage established thereby.
“1st” to “6th” shown in FIG. 2 means the first to sixth forward shift speeds, and the gear ratio increases from the first shift speed “1st” toward the sixth shift speed “6th”. (The rotational speed Nin of the input shaft 22 / the rotational speed Nout of the output shaft 32) is reduced, and the gear ratio of the fourth gear stage “4th” is set to 1.0. In FIG. 2, “◯” represents engagement, blank represents release, “(◯)” represents engagement during engine braking, and “Δ” represents engagement not involved in power transmission.

  FIG. 3 is a block diagram showing a main part of a control system for controlling the automatic transmission according to the first embodiment of the present invention.

  The electronic control device 41 includes a CPU (Central Processing Unit) 42, a RAM (Random Access Memory) 43, a ROM (Read Only Memory) 44, a standby RAM (hereinafter referred to as “SRAM”) 45, and an EEPROM (Erasable Programmable ROM) 46. The microcomputer includes an input interface and an output interface (not shown). The CPU 42 performs output control of the engine 11, shift control of the automatic transmission 1, and the like by performing signal processing according to a program stored in the ROM 44 in advance while using the temporary storage function of the RAM 43. If necessary, it is configured separately for engine control, shift control, and brake control.

  An accelerator operation amount sensor 51, an output shaft rotational speed sensor 52, a throttle opening sensor 53, a vehicle speed sensor 54, a lever position sensor 55, a turbine rotational speed sensor 56, and the like are connected to the electronic control unit 41 via a harness or the like. ing.

The accelerator operation amount sensor 51 detects an operation amount (hereinafter referred to as “accelerator pedal operation amount”) Acc of an accelerator pedal 57 provided in the driver's seat of the vehicle, and electronically outputs a signal representing the detected accelerator pedal operation amount Acc. The data is output to the control device 41.
The output shaft rotational speed sensor 52 detects the rotational speed (hereinafter referred to as “output shaft rotational speed”) N _OUT of the output shaft 32 of the speed change mechanism 13 and electronically controls a signal representing the detected output shaft rotational speed N _OUT. The data is output to the device 41.

The throttle opening sensor 53 is provided in the intake pipe of the engine 11 and detects the opening (hereinafter referred to as “throttle opening”) θ _TH of a throttle valve 48 that is opened and closed according to the operation of the accelerator pedal 57. A signal indicating the detected throttle opening θ _TH is output to the electronic control unit 41.
The vehicle speed sensor 54 detects the vehicle speed V of the vehicle from the output shaft rotation speed N _OUT and outputs a signal representing the detected vehicle speed V to the electronic control device 41.

The lever position sensor 55 detects the lever position (operation position) P _SH of the shift lever 58 and outputs a signal representing the detected lever position P _SH to the electronic control device 41.
The turbine rotation speed sensor 56 detects the rotation speed (hereinafter referred to as “turbine rotation speed”) NT of the input shaft 22 of the speed change mechanism 13 and outputs a signal representing the detected turbine rotation speed NT to the electronic control unit 41. It is like that.

  The hydraulic control circuit 59 includes shift solenoid valves Sol1 to Sol5 controlled by a shift command signal from the electronic control device 41, linear solenoid valves SL1 and SL2, a linear solenoid valve SLU mainly controlling lockup hydraulic pressure, and a main solenoid valve SLU. Is provided with a linear solenoid valve SLT for controlling the line hydraulic pressure. The hydraulic oil in the hydraulic control circuit 59 is supplied to the lockup clutch 26 and the like.

The CPU 42 controls opening / closing of the throttle valve 48 by the throttle actuator 47. For example, the CPU 42 controls the throttle actuator 47 so that the throttle valve opening θ _TH is increased or decreased based on the accelerator operation amount Acc detected by the accelerator operation amount sensor 51. The CPU 42 controls the fuel injection device 49 for controlling the fuel injection amount, and controls the ignition device 50 such as an igniter for controlling the ignition timing. Further, the CPU 42, when an operation condition for bringing the lock-up clutch 26 into an engaged state or a released state is established by the vehicle speed V detected by the vehicle speed sensor 54 and the throttle valve opening degree θ _TH detected by the throttle opening degree sensor 53, The linear solenoid valve SLU is controlled according to the engaged state or the released state.

  The SRAM 45 is an electrically writable volatile semiconductor memory, and a new learning value Gn representing a correction value for correcting a hydraulic pressure command value when the clutch C and the brake B of the automatic transmission 1 are engaged is stored. It comes to memorize. The correction value is learned when the operating characteristics of the clutch C and the brake B and the hydraulic characteristics of the solenoid valves Sol1 to Sol5 and the linear solenoid valves SL1 and SL2 change over time. This is because they are shifted.

  The EEPROM 46 is an electrically writable non-volatile semiconductor memory, and saves and stores a new learning value Gn stored in the SRAM 45 as an existing learning value Gex. Further, an upper limit value of the number of times of writing is set in the EEPROM 46. When the number of times of writing exceeds the upper limit value, the EEPROM 46 cannot store the new learning value Gn as the existing learning value Gex. The EEPROM 46 stores a write count Nr indicating the number of times of electrical writing.

  The CPU 42 initializes the data in the SRAM 45 when power supply from a battery (not shown) to the SRAM 45 is stopped or when the data in the SRAM 45 becomes abnormal. When this initialization is performed, the new learning value Gn stored in the SRAM 45 is rewritten to the initial value. Therefore, the CPU 42 stores the new learning value Gn as the existing learning value Gex in the EEPROM 46 by writing the new learning value Gn stored in the SRAM 45 into the EEPROM 46 at an appropriate timing.

  Further, the CPU 42 performs the above-described initialization process and restores the data by writing the existing learning value Gex stored in the EEPROM 46 into the SRAM 45.

The characteristic configuration of the CPU 42 according to the first embodiment of the present invention will be described below.
The CPU 42 calculates a learning value change amount Cg representing a difference between the new learning value Gn stored in the SRAM 45 and the existing learning value Gex stored in the EEPROM 46. That is, the CPU 42 constitutes a difference calculation unit of the present invention.
Further, the CPU 42 calculates a write permission change amount Cp that increases as the number of times of writing Nr to the EEPROM 46 increases. That is, the CPU 42 constitutes the write permission change amount calculating means of the present invention.

Further, the CPU 42 determines whether or not the learning value change amount Cg is equal to or larger than the write permission change amount Cp. That is, the CPU 42 constitutes a difference determination unit of the present invention.
Further, when the CPU 42 determines that the learning value change amount Cg is equal to or larger than the write permission change amount Cp, the CPU 42 writes the new learning value Gn stored in the SRAM 45 into the EEPROM 46. That is, the CPU 42 constitutes the writing means of the present invention.

Next, the operation will be described.
FIG. 4 is a flowchart showing the writing process of the EEPROM according to the first embodiment of the present invention. The processing described below is realized by a program stored in the ROM 44 in advance, and is performed at predetermined time intervals by the CPU 42 of the electronic control device 41.

As shown in FIG. 4, first, the CPU 42 determines whether or not the number of shifts Nsh is equal to or greater than a predetermined value N (step S1). Here, the number of shifts Nsh is a value that increases by 1 each time the shift of the automatic transmission 1 is completed. The CPU 42 calculates a value corresponding to the turbine rotational speed based on the output shaft rotational speed N _OUT detected by the output shaft rotational speed sensor 52 and the gear ratio of a predetermined gear. Then, the CPU 42 compares the calculated value with the turbine rotational speed NT detected by the turbine rotational speed sensor 56, and shifts from a state where the comparison result is outside the predetermined range to a state within the predetermined range. When it is determined that the shift has been completed, the shift number Nsh is incremented by one.

  If the CPU 42 determines that the number of shifts Nsh is less than a predetermined value N (NO in step S1), the CPU 42 ends the process without writing the new learning value Gn stored in the SRAM 45 into the EEPROM 46. To do. On the other hand, if the CPU 42 determines that the number of shifts Nsh is equal to or greater than a predetermined value N (YES in step S1), the CPU 42 reads the new learning value Gn from the SRAM 45 and the existing learning value Gex from the EEPROM 46. Then, the write count Nr is read (step S2).

  Next, the CPU 42 calculates a learning value change amount Cg representing a difference between the new learning value Gn and the existing learning value Gex (step S3).

Next, the CPU 42 calculates a write permission change amount Cp based on the write count Nr (step S4). For example, the CPU 42 calculates the write permission change amount Cp that increases as the number of times of writing Nr to the EEPROM 46 increases by the following equation (1). Here, a is a positive value.
(Formula 1)
Cp = aNr + b (a and b are constants) (1)
Note that the CPU 42 only has to calculate the write permission change amount Cp so as to increase as the number of times of writing Nr to the EEPROM 46 increases. For example, the write permission change amount Cp increases as the number of times of writing Nr to the EEPROM 46 increases. You may calculate so that it may become large in steps.

  Next, the CPU 42 determines whether or not the learned value change amount Cg is greater than or equal to the write permission change amount Cp (step S5), and determines that the learned value change amount Cg is less than the write permission change amount Cp ( If NO in step S5), the process ends without writing the new learning value Gn stored in the SRAM 45 into the EEPROM 46.

  On the other hand, when the CPU 42 determines that the learning value change amount Cg is equal to or larger than the write permission change amount Cp (YES in step S5), the CPU 42 writes the new learning value Gn and the write count Nr in the EEPROM 46 (step S6). ), The process is terminated. Here, the EEPROM 46 stores the new learning value Gn as the existing learning value Gex.

  As described above, according to the CPU 42 according to the present embodiment, the learning value change amount Cg representing the difference between the new learning value Gn stored in the SRAM 45 and the existing learning value Gex stored in the EEPROM 46 is the EEPROM 46. Since the new learning value Gn stored in the SRAM 45 is written in the EEPROM 46 when the write permission change amount Cp increases with the increase in the number of times of writing Nr, the learning value does not converge at an initial stage. It is possible to prevent the difference between the new learning value Gn stored in the SRAM 45 and the existing learning value Gex stored in the EEPROM 46 from increasing. Furthermore, since the time until the upper limit value of the number of times of writing in the EEPROM 46 is reached becomes longer, the latest new learning value Gn stored in the SRAM 45 can be prevented from being written in the EEPROM 46.

  In the present embodiment, the CPU 42 proceeds to step S2 when the number of shifts Nsh is equal to or greater than a predetermined value N. However, the present invention is not limited to this, and an ignition switch (not shown) is turned on. If it is switched off, the process may move to step S2. The reason for this may be that a shift is performed according to the driving conditions while the ignition switch is turned on and the vehicle is traveling.

(Second Embodiment)
The main part of the control system for controlling the vehicle drive device and the automatic transmission according to the second embodiment is the main part of the control system for controlling the vehicle drive device and the automatic transmission according to the first embodiment and the CPU 42. Since the configuration is substantially the same except for the SRAM 45 and the SRAM 45, the description of the configuration other than the CPU 42 and the SRAM 45 is omitted. Hereinafter, the configuration will be described with reference to FIG.

  The SRAM 45 stores a write non-permission number Nnpr that represents the number of times that the learning value change amount Cg is continuously determined not to be greater than or equal to the write permission change amount Cp.

The characteristic configuration of the CPU 42 according to the second embodiment of the present invention will be described below.
The CPU 42 counts the number of write disapproval times Nnpr that represents the number of times that the learning value change amount Cg is continuously determined not to be greater than or equal to the write permission change amount Cp. That is, the CPU 42 constitutes a writing non-permission count unit of the present invention.
Further, when the CPU 42 determines that the learning value change amount Cg is not equal to or greater than the write permission change amount Cp, the CPU 42 determines whether or not the write disapproval number Nnpr is equal to or greater than a predetermined number Nth. That is, the CPU 42 constitutes the write non-permission count determination means of the present invention.
On the other hand, when the CPU 42 determines that the write disapproval count Nnpr is equal to or greater than the predetermined count Nth, the CPU 42 writes the new learning value Gn stored in the SRAM 45 into the EEPROM 46, that is, the CPU 42 Constitutes the writing means of the present invention.

Next, the operation will be described.
FIG. 5 is a flowchart showing the writing process of the EEPROM according to the second embodiment of the present invention. The processing described below is realized by a program stored in the ROM 44 in advance, and is performed at predetermined time intervals by the CPU 42 of the electronic control device 41. Moreover, the same step number is attached | subjected about what performs the same process as 1st Embodiment among the processes in 2nd Embodiment, and detailed description is the same as 1st Embodiment. Therefore, the description thereof is omitted.

  As shown in FIG. 5, first, the CPU 42 determines whether or not the number of shifts Nsh has become equal to or greater than a predetermined value N (step S1).

  If the CPU 42 determines that the number of shifts Nsh is less than a predetermined value N (NO in step S1), the CPU 42 ends the process without writing the new learning value Gn stored in the SRAM 45 into the EEPROM 46. To do. On the other hand, when the CPU 42 determines that the number of shifts Nsh is equal to or greater than a predetermined value N (YES in step S1), the CPU 42 reads the new learning value Gn and the write disapproval number Nnpr from the SRAM 45, The existing learning value Gex and the write count Nr are read from the EEPROM 46 (step S11).

  Next, the CPU 42 calculates a learning value change amount Cg representing a difference between the new learning value Gn and the existing learning value Gex (step S3), and calculates a write permission change amount Cp based on the number of times of writing Nr (step S4). ).

  Next, the CPU 42 determines whether or not the learned value change amount Cg is greater than or equal to the write permission change amount Cp (step S5), and determines that the learned value change amount Cg is greater than or equal to the write permission change amount Cp ( If YES in step S5), the process proceeds to step S6.

  On the other hand, if the CPU 42 determines that the learned value change amount Cg is less than the write permission change amount Cp (NO in step S5), is the write disapproval count Nnpr equal to or greater than a predetermined value Nth? It is determined whether or not (step S12). Here, when the CPU 42 determines that the write disapproval count Nnpr is equal to or greater than a predetermined value Nth (YES in step S12), the CPU 42 proceeds to step S6.

  The CPU 42 determines that the learning value change amount Cg is greater than or equal to the write permission change amount Cp (in the case of YES in step S5), or determines that the write non-permission number Nnpr is greater than or equal to a predetermined value Nth. If this is the case (YES in step S12), the new learning value Gn and the write count Nr are written to the EEPROM 46 (step S6). Here, the EEPROM 46 stores the new learning value Gn as the existing learning value Gex. Next, the CPU 42 sets the write disapproval count Nnpr stored in the SRAM 45 to 0 (step S13) and ends the process.

  Further, when the CPU 42 determines that the write non-permission number Nnpr is less than a predetermined value Nth (NO in step S12), the CPU 42 increments the write non-permission number Nnpr stored in the SRAM 45 (step S12). S14), the process is terminated.

  As described above, according to the CPU 42 according to the present embodiment, when a new learning value is not written from the SRAM 45 to the EEPROM 46 until the predetermined number Nth is reached, the new value stored in the SRAM 45 is stored. Since the learning value Gn is written in the EEPROM 46, the learning value converged more accurately can be written in the EEPROM 46.

  As described above, in the present invention, the difference between the learning value stored in the volatile memory and the learning value stored in the non-volatile memory at the initial stage where the learning value has not converged becomes large. In addition, the latest learning value stored in the volatile memory can be prevented from being written to the nonvolatile memory, and the learning value in the shift control of the automatic transmission is volatile. This is useful for a control device for an automatic transmission that writes data from a non-volatile memory to a nonvolatile memory.

1 is a skeleton diagram showing a configuration of a vehicle drive device according to a first embodiment of the present invention. It is a figure which shows the relationship between the combination of the action | operation of the several hydraulic friction engagement apparatus in the automatic transmission which concerns on the 1st Embodiment of this invention, and the gear stage established by it. It is a block diagram which shows the principal part of the control system which controls the automatic transmission which concerns on the 1st Embodiment of this invention. It is a flowchart which shows the write-in process of EEPROM which concerns on the 1st Embodiment of this invention. It is a flowchart which shows the write-in process of EEPROM which concerns on the 2nd Embodiment of this invention.

Explanation of symbols

1 automatic transmission 41 electronic control device 42 CPU (difference calculating means, write permission change amount calculating means, difference determining means, writing means, write non-permission count counting means, write non-permission count determining means)
43 RAM
44 ROM
45 SRAM (volatile memory)
46 EEPROM (nonvolatile memory)

Claims (2)

An electrically writable volatile memory and a non-volatile memory, and a learning value for correcting a hydraulic pressure command value when engaging a friction engagement element of an automatic transmission from the volatile memory to the non-volatile memory In the automatic transmission control device that writes to
Difference calculating means for calculating a difference between a learning value stored in the volatile memory and a learning value stored in the nonvolatile memory;
Write permission change amount calculating means for calculating a write permission change amount that increases as the number of times of writing to the nonvolatile memory increases;
Difference determining means for determining whether or not the difference calculated by the difference calculating means is greater than or equal to the write permission change amount calculated by the write permission change amount calculating means;
Write means for writing the learned value stored in the volatile memory to the non-volatile memory when the difference is determined by the difference determining means to be greater than or equal to the write permission change amount. A control device for an automatic transmission. A write non-permission count counting unit that counts the number of write non-permissions representing the number of times that the difference determination unit continuously determines that the difference is not equal to or greater than the write permission change amount;
If it is determined by the difference determination means that the difference is not greater than or equal to the write permission change amount, it is determined whether or not the write disapproval count counted by the write disapproval count counting means is greater than or equal to a predetermined number A writing non-permission count determination means,
If the write means determines that the write non-permission count is greater than or equal to a predetermined number by the write non-permission count determination means, the learning value stored in the volatile memory is stored in the non-volatile memory. 2. The control device for an automatic transmission according to claim 1, wherein writing is performed.

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