JP2760824B2 - Control device for electronically controlled automatic transmission - Google Patents

Description

The present invention relates to a control device for an electronically controlled automatic transmission,
In particular, the present invention relates to a device for detecting a short circuit between linear solenoid terminals of the transmission.

(Prior art) As a hydraulic actuator in a conventional electronically controlled automatic transmission, in addition to a solenoid on / off type, a linear output type that continuously changes the hydraulic pressure according to the amount of current flowing through the solenoid. There are things.

This linear output type is controlled so that the current value under certain conditions always coincides with the target value by current feedback control so as to correct variations due to various external factors considered due to the characteristics of the application. doing.

Variations due to various external factors referred to here include variations in the voltage for driving the solenoid, variations in the resistance of the original solenoid itself, the temperature of the oil in which the solenoid is immersed (oil temperature), and the resistance due to self-heating of the solenoid. And the like.

In addition, in order to perform feedback control of the hydraulic pressure with high accuracy, it is necessary to connect the electronic control unit through current to both the positive and negative terminals of the solenoid. In this regard, the linear output type is a conventional on / off type solenoid. It is different from the body earth type as in some of the above.

(Problems to be Solved by the Invention) As described above, when the + and-terminals of the linear solenoid of the automatic transmission are short-circuited, it is difficult to detect the failure.
There is a need for a measure against such a short-circuit failure.

The present invention has been made in view of the above circumstances, and has as its object to provide a control device for an electronically controlled automatic transmission capable of accurately detecting a short circuit failure between terminals of a solenoid and performing fail-safe control thereof.

(Means for Solving the Problems) In order to achieve the above object, the present invention provides an electronically controlled automatic transmission having a linear solenoid that performs feedback control by an electronic control unit. A means for sampling a deviation between a target value of the measured value of the actual amount of electricity and a means for executing the sampling a predetermined number of times to obtain a sum of each sampling; and a means for comparing the sum with a reference value. Based on the comparison result, it is determined whether or not there is a short between the terminals of the linear solenoid.

(Operation and Effect of the Invention) According to the present invention, as described above, attention is paid to the electrical characteristics that the linear solenoid is not a simple resistor but a coil and has an inductance. Although the voltage value (average voltage value) detected by the detection resistor by the current feedback control is the same as in the case of the above, since the ripple characteristics are different, the difference between the terminals of the linear solenoid is detected by detecting the difference in the ripple characteristics. A short can be detected. That is, the voltage ripple characteristic differs between the normal state (see FIG. 3) and the short-circuit state between the terminals of the linear solenoid (see FIG. 4). In the short-circuit state between the terminals, the inductance of the linear solenoid is lost. The ripple value increases. In the normal state, this voltage has a characteristic of moving around a target current value as shown in FIG. 3, so that a voltage corresponding to the target current value, here, 0.
By sampling and summing the absolute value of the difference between 9A × 0.9Ω = 0.81V and the actually input voltage, the magnitude of the ripple can be detected. If the value of the ripple width detected in this way is larger than a certain reference value, it is determined that the solenoid is short-circuited between the terminals, so that a failure can be accurately detected.

As described above, when a failure is detected, appropriate measures can be taken by fail-safe control, the driver can be notified of the failure and the need for repair can be indicated, and the failure location can be determined by diagnosis. You can also search for

(Example) Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

1 is an overall configuration diagram of an electronically controlled automatic transmission to which the present invention is applied, FIG. 2 is an interface circuit diagram of a linear solenoid of the transmission, and FIG. 3 is a monitor voltage characteristic diagram of the linear solenoid in a normal state. FIG. 4 is a monitor voltage characteristic diagram when the terminals of the linear solenoid are short-circuited.

In FIG. 1, 1 is a throttle position sensor (hereinafter, referred to as a throttle sensor) for detecting a throttle opening, 2 is a vehicle speed sensor, 3 is an electronic control unit, and the electronic control unit 3 includes interface circuits 4, 5, Microcomputer 6, first shift solenoid drive circuit 7, second shift solenoid drive circuit 8, lock-up solenoid drive circuit 9, hydraulic control solenoid drive circuit 10, hydraulic control solenoid monitor circuit 11, failure warning device drive It comprises a circuit 16. Reference numeral 12 denotes a first shift solenoid, reference numeral 13 denotes a second shift solenoid, reference numeral 14 denotes a lock-up solenoid, reference numeral 15 denotes a hydraulic control solenoid, and reference numeral 17 denotes a failure warning device, each of which is connected to the electronic control unit 3.

In the second diagram, the drive circuit 10 of the hydraulic control solenoid 15, the battery voltage B, switching PNP transistor T _r1, overcurrent protection PNP transistor T _r2, NPN transistor T _r3 receiving a signal from the microcomputer 6 , Capacitors C _{1 to} C ₃ , resistors R ₁ and R _{3 to} R ₈ , a flywheel diode D ₁ , and a negative logic NOT circuit 16.

The monitor circuit 11 includes a resistor R ₂ (combined resistor of the resistor R ₂₁ and the resistor R ₂₂ ), R ₉ and R ₁₀ , capacitors C ₄ and C ₅ , diodes D ₂ and D _{2
Consists of three} .

 Next, the operation of this circuit will be described.

First, when the command signal Low level from the microcomputer 6 is output, the signal is inverted to High level signal by the negative logic NOT circuit 16, increases the base potential of the transistor T _r3, the transistor T _r3 is turned on. Then, down the base potential of the switching transistor T _r1, the transistor T _r1 turns on, are energized to the hydraulic control solenoid 15 through the detection resistor R ₁ from the battery voltage B. Its energized state is monitored by the detection resistor R _2, the information is read into the microcomputer 6.

On the other hand, when the command signal of the High level from the microcomputer 6 is output, the signal is a negative logic NOT circuit 16 is inverted to a Low level signal, lowers the base potential of the transistor T _r3, the transistor T _r3 is turned off . Then, the base potential of the switching transistor T _r1 rises, the transistor T _r1 is by turning off, hydraulic control solenoid 15 is de-energized. Its energized state is monitored by the detection resistor R _2, the information is read into the microcomputer 6.

In such a circuit configuration, it is difficult to detect a short circuit between terminals of the hydraulic control solenoid 15. The reason is that current feedback control is performed so as to correct variations due to various external factors of the solenoid as described above. That is, although the resistance value of the hydraulic control solenoid 15 is generally 2 to 5 Ω, even if the resistance value becomes 0 Ω due to a short circuit between the terminals, the electronic control device 6 cannot distinguish it from the variation of the external factor,
This is because normal current feedback control is performed.

 This will be described in more detail with reference to FIG.

In this figure, B is the battery voltage, 9-16V
Range. R ₁ and R ₂ are hydraulic control solenoid 15
To a resistor connected in series, R ₁ is 0.22-ohm ± 5% in the over-current protection resistor, R ₂ is 0.9Ω ± 1% in the resistance for detecting the monitor current of the current feedback (1.8Omu Is a parallel circuit).

Further, the variation in resistance of the hydraulic control solenoid 15 itself is in the range of 2 to 5 Ω in consideration of the variation between products and the variation in environmental temperature. And this solenoid 15
The working current range is 0.3 to 1 A, and it is necessary to have a capability of adjusting the current to a constant value in consideration of all the above variations. The current is adjusted by the microcomputer 6
This is performed by 300Hz PWM (pulse width modulation) control. Here, the minimum value and the maximum value of the PWM duty range for satisfying the above condition are as follows.

The minimum value Dmin of the PWM duty range is [0.3A / {16V / 2 + (0.22 + 0.9) × 0.95Ω}] × 100 = 5.7% The maximum value Dmax is [1A / {9V / 5 + (0.22 + 0 .9) × 1.05Ω｝] × 100 = 68.6% Therefore, the minimum duty range is 5.7
The maximum is 68.6%, and in practice, it is set at 3 to 75% with a margin.

Here, considering the case where the terminals of the hydraulic control solenoid 15 are short-circuited, the minimum value Dmin of the duty range of the PMW is [0.3A / ｛16V / (0.22 + 0.9) × 0.95Ω] × 100 = 2.0 % The maximum value Dmax is [1A / {9V / (0.22 + 0.9) × 1.05Ω} × 100 = 13.1%, and the variable range of duty is 2.0 to 13.1%.
This is substantially included in the normal duty variable range.

Therefore, even when the terminals of the hydraulic control solenoid 15 are short-circuited, the current is adjusted by the normal current feedback control, and the microcomputer 6 detects the terminal short-circuit failure from the monitored average current value. Difficult to detect.

As described above, even if a short circuit occurs between the terminals of the hydraulic control solenoid 15, it cannot be accurately detected, and there is a difficulty in appropriate processing such as fail safe.

Further, in the electronically controlled automatic transmission system, two shift control shift solenoids 12 and 13 attached to a hydraulic circuit in the T / M and a lock based on signals from the throttle sensor 1 and the vehicle speed sensor 2. Up (L-u
p) The solenoid 14 and the hydraulic control solenoid 15 that controls the line pressure, which is the basis of the hydraulic circuit, are controlled by the electronic control unit 3. Here, the shift solenoids 12, 13 are used.
The lock-up solenoid 14 is an on / off type solenoid, and the hydraulic control solenoid 15 is a linear solenoid in which the oil pressure changes in proportion to an energizing current.

The hydraulic control solenoid 15 adjusts the throttle pressure by 0.5 to 0.5 A between the current values of 1 to 0.3 A output by the electronic control unit 3 based on the throttle opening information from the throttle sensor 1.
By controlling up to 4.5 kg / cm ² , the line pressure proportional to the throttle pressure is controlled. The drive circuit 10 and the monitor circuit 11 of the hydraulic control solenoid 15 are as shown in FIG. 2, and correct the variation due to the external factors as described above (battery voltage variation, solenoid resistance variation, etc.). Therefore, the current feedback control is configured. Therefore, both the + and-terminals of the hydraulic control solenoid 15 are connected to the electronic control unit 3.

Therefore, if the + and-terminals of the hydraulic control solenoid 15 are short-circuited, the current flowing through the solenoid 15 becomes zero, the throttle pressure becomes 5 kg / cm ^2, and the line pressure is higher than the normal maximum pressure. Pressure. If this condition is left unchecked, the shift control of the automatic transmission will be performed at this high line pressure, causing a very large shock during shifting and a secondary failure due to high oil pressure inside the T / M Therefore, it is necessary to reliably detect the short-circuit failure between the terminals, perform fail-safe control, and issue a failure alarm.

The present invention focuses on the difference in the ripple characteristics of the monitor voltage at the time when the + and-both terminals of the hydraulic control solenoid (linear solenoid) 15 are short-circuited, and detects the magnitude of the ripple. It is to detect a failure.

In the following, a comparison is made between the monitor voltage when the normal linear solenoid 15 shown in FIG. 3 is energized and the monitor voltage when the short circuit between the positive and negative terminals of the linear solenoid 15 shown in FIG. 4 is made. explain. Here, the voltage at point a on the output side of the monitor circuit 11 is monitored.

In the normal state, as shown in FIG. 3, a voltage value corresponding to a target current value, here, 0.9A × 0.9
The absolute value of the difference between Ω = 0.81V and the actually input voltage is sampled, summed up a certain number of times to obtain the sum, and when the sum is larger than a certain reference value, the linear solenoid
By determining that there is a 15-terminal short-circuit failure, the short-circuit failure can be accurately detected.

That is, the ripple in the normal state is as shown in FIG.
While the inductance is about 10 mV due to the inductance of the linear solenoid 15, the ripple at the time of a short-circuit fault has no sawtooth wave (30
0Hz) and reaches about 60mV.

In this embodiment, the sampling time is every 4 ms, the total number of times (sampling number) is 400 times, and the case where the total A / D value is 1000 or more is defined as the short-circuit between terminals.

Here, the A / D value is the result of performing 10-bit (1024) A / D conversion on the basis of 5 V inside the microcomputer 6, and the total of 1000 A / D values is 4.88 V Is shown.

FIG. 5 shows experimental data, and shows the total of A / D values in the normal state and the short-circuit state between terminals.

As is clear from this figure, the total value of A / D is usually 4
Since it is the 00th place and is 1100th to 1350th in a short state, a failure can be reliably detected by setting the reference value to 1000.

Hereinafter, a procedure for detecting a failure when the terminals of the linear solenoid of the present invention are short-circuited will be described with reference to FIG.

First, it is determined whether the target A / D value is stable (step).

As a result, if the A / D value is stable, it is determined whether or not the target A / D value is equal to or more than the reference value 9E (0.85A) (step).

As a result, if the A / D value is equal to or larger than the reference value, the difference between the monitor (sampling) A / D value and the target A / D value is obtained (step).

Next, it is determined whether or not the difference between the A / D values is equal to or greater than 15 in order to remove noise (step).

Next, it is determined whether the number of A / D inputs is less than 45 times.
That is, a standby time of 0.2 seconds is set (step).

As a result, if the number of A / D inputs is not less than 45, the sum of the difference between the A / D values = the sum of the differences up to the previous time + the difference between the current A / D values (step).

Next, it is determined whether the A / D input count 400 has been added (step).

As a result, when 400 A / D inputs are added, A / D
It is determined whether the sum of the differences between the D values is less than the reference value 1000 (step).

As a result, if the sum of the difference between the A / D values is not less than the reference value 1000, the detection flag is set as a short-circuit failure between the linear solenoid terminals (step).

The current target A / D value is stored as comparison data (step).

In the step, the sum of the difference between the A / D values is equal to the reference value 100.
If it is less than 0, the data of the sum of the A / D value differences is cleared (step).

Next, the number of A / D inputs is cleared (step), and the process proceeds to step.

FIG. 7 is a diagram showing a first application example of a specific hydraulic control device for an automatic transmission according to the present invention.

As shown in the figure, the hydraulic pressure finely adjusted by the linear solenoid valve 23 is applied to the orifice control valve 31.
Is supplied for adjusting the valve position. That is, the solenoid modulator valve 29 receives the hydraulic pressure adjusted by the primary regulator valve (not shown), and adjusts the hydraulic pressure for each solenoid. The hydraulic pressure adjusted by the solenoid modulator valve 29 is applied to a linear solenoid valve.
It is supplied to 23 ports a. The linear solenoid valve
23 is controlled linearly by a signal sent from a control device (not shown), adjusts the hydraulic pressure supplied to the port a, and sends the pressure to the port b.

Then, hydraulic pressure from the port b is supplied to the port b ₁ of the solenoid relay valve 26. The solenoid relay valve 26, have made it possible to take the second position in the right half position and the left half position, the port b ₁ is connected to port c is in the right half position, the orifice control valve 31
Is supplied to the port e at one end of the valve. On the other hand, in the case of the left half position, the port b ₁ is connected to the port d, the hydraulic pressure finely adjusted by the solenoid relay valve 26 is supplied to the lock-up operation device, and the lock-up on / off control is performed. Used for

The orifice control valve 31 is finely adjusted by the linear solenoid valve 23, and the valve position is adjusted by the balance between the hydraulic pressure supplied to the port e and the urging force of the spring 32. The hydraulic pressure from the manual valve 22 is supplied to the orifice control valve 31 through a port f, and the forward clutch C is supplied through a port g in the left half position and through ports g and h in the right half position. It is sent to the _1. Therefore,
As the hydraulic pressure is supplied from the linear solenoid valve 23, when the valve of the orifice control valve 31 gradually decreases, a small amount of oil first passes through the port g, and a large amount of oil later passes through the ports g and h. Forward clutch C ₁
Therefore, the shock at the time of shifting the shift is reduced. Incidentally, the oil from the manual valve 22, in addition via the orifice control valve 31, is connected to the forward clutch C ₁ via a throttle 34 and a check valve 35 with the diaphragm 36. Restrictor 36 with check valve 35
The effect can be more than the time the supply of oil amount at the time of drain to the forward clutch C _1.

As described above, the solenoid relay valve 26 distributes the hydraulic pressure from the linear solenoid valve 23 for adjusting the valve position of the orifice control valve 31 or for controlling the lock-up operation device. Therefore, two positions, a right half position and a left half position, are taken. Therefore, the port i of the one end of the solenoid relay valve 26, 1-2 shift port i ₁ from the second coast brake B ₁ engagement oil pressure of the valve 27, also the port j of the other end of the solenoid relay valve 26, 1-
₂ engagement oil pressure 2 shift Second from the port i ₁ of the valve 27 the brake B is adapted to be supplied. Further, a spring 33 is provided on the valve end face on the port i side to urge the valve downward.

Here, D, 2nd, in the first speed of the L range, since none of the second coast brake B ₁ and second brake B ₂ is not engaged, the port i, no supply of hydraulic pressure with j, the solenoid relay valve 26 Is placed in the right half position only by the biasing force of the spring 33.

Then, D, 2nd, when the second speed or more L-range, the hydraulic pressure is supplied to the second brake B ₂ is engaged with the port j, 2n
d, the second speed of the L range, the second coast brake B ₁ as well as the second brake B ₂ is also engaged, hydraulic pressure is supplied to port i. By the way, when hydraulic pressure is supplied to both ports i and j, both hydraulic pressures are
Are supplied through the 1-2 shift valve 27 or the 2-3 shift valve 28 and have the same pressure, so that both end faces of the solenoid relay valve 26 are pressed by the same force. Therefore, the solenoid relay valve 26 is connected to the spring 33
Takes the right half position only by the urging force of.

That is, when shifting from the N, R, and P ranges to the first speed of the D, 2nd, and L ranges, the solenoid relay valve 26
Always takes the right half position, and supplies the hydraulic pressure of the linear solenoid valve 23 to the orifice control valve 31 to reduce shift shock.

In addition, when the speed is higher than the second speed in the D, 2nd, and L ranges, it is necessary to operate the lock-up mechanism. Therefore, the solenoid relay valve 26 is in the left half position, and the hydraulic pressure of the linear solenoid valve 23 is reduced by the lock-up control valve.
24 and lock-up relay valve 25. Note that 2n
It is necessary to release the lock-up when starting the 2nd speed in the d range, but as described above, in the 2nd speed in the 2nd, L range, the solenoid relay valve 26
Takes the right half position, the hydraulic pressure of the linear solenoid valve 23 is not supplied to either the lock-up control valve 24 or the lock-up relay valve 25.

According to the present invention, in the hydraulic control system configured as described above, the electronic control unit 3 is connected to and driven by the solenoid of the linear solenoid valve 23 described above. Thereby,
The short-circuit failure between the terminals of the solenoid of the linear solenoid valve 23 can be reliably detected.

FIG. 8 is a diagram showing a second application example of a specific hydraulic control device for an automatic transmission according to the present invention.

As shown in this figure, overdrive direct clutch C ₀ is supplied with oil from the port a of the 3-4 shift valve 55, overdrive brake B ₀ is the oil from the port b of the 3-4 shift valve 55 They are being supplied. The 3-4 shift valve 55 takes two positions by turning on / off the solenoid valve 57, receives the supply of the hydraulic pressure regulated by the primary regulator valve 52 at the port c, and connects the port a with the port b. Selectively. That is, at the 1st, 2nd, and 3rd speeds, the solenoid valve 57 is in the ON state, and is drained to the port d.
Is removed, and the 3-4 shift valve 55 is placed at the right half position. Therefore, the hydraulic pressure from the primary regulator valve 52 is
It will be sent to C _0. When the fourth speed is reached, the solenoid valve 57 is turned off, hydraulic pressure is supplied to the port d, and the 3-4 shift valve 55 is placed at the left half position,
Hydraulic pressure from the primary regulator valve 52 is transmitted to the overdrive brake B _0.

Conversely, 4-3 when downshifting, hydraulic pressure from the primary regulator valve 52 that has been sent to the overdrive brake B ₀ is to be supplied to the overdrive direct clutch C ₀ by switching the 3-4 shift valve 55 become.

Further, the oil passage for the engagement of the overdrive direct clutch C ₀ extending from the port a, the diaphragm 61, with throttle check valve
62 have been provided, in their more overdrive direct clutch C ₀ side, overdrive direct clutch C ₀ accumulator 54 is branched and connected. The overdrive direct clutch C ₀ accumulator 54
Is intended to prevent the supply of rapid oil into overdrive direct clutch C _0, the oil enters the upper chamber of the overdrive direct clutch C ₀ accumulator 54 via the port e, the piston 63 spring 64 Press down against. When the constant pressure is obtained, so that the engagement of the first overdrive direct clutch C ₀ is performed.

On the other hand, overdrive brake B ₀ extending from port b
The engagement oil passage, the diaphragm 65, though the check valve with the diaphragm 66 is disposed, in their more overdrive brake B ₀ side, overdrive brake B ₀ accumulator 56 is branched and connected. The overdrive brake B ₀ accumulator 56 is for preventing the supply of rapid oil into overdrive brake B _0, the oil accumulator for the overdrive brake B ₀ through port f 56
And pushes the piston 67 up against the spring 68. When the constant pressure is obtained, so that the engagement of the first overdrive brake B ₀ is performed.

Here, each of the accumulators 54 and 56 has a piston 6
Ports g and h are provided on the back pressure side of 3,67. And
The port g is connected to the port i of the cutoff valve 60, and the supply and stop of the hydraulic pressure are performed depending on the position of the cutoff valve 60. Further, the port h is connected to the port j of the accumulator control valve 58, and the supply and stop of the hydraulic pressure are performed depending on the position of the accumulator control valve 58. Then, hydraulic pressure becomes resistance to the operation of the accumulator 54, 56 by providing a back pressure against the accumulator 54, overdrive direct clutch C ₀ and overdrive brake supplied to these ports g, h It acts to speed up and disengage B ₀ .

 The control of the back pressure is performed as follows.

Hydraulic pressure regulated by the solenoid modulator valve 59, is supplied to the port k of the accumulator control valve 58, the order accumulator control valve 58 is in the normal left-half position, an accumulator for overdrive brake B ₀ through port j 56 Supplied to the back pressure side port h and cut-off valve through port j.
It is supplied to 60 ports l.

By the way, the cut-off valve 60 is set at two positions by supplying a hydraulic pressure according to the acceleration / deceleration state of the vehicle, for example, a hydraulic pressure from the throttle valve 53. That is, when the accelerator is turned on, hydraulic pressure is supplied from the port m of the throttle valve 53 to the ports n and p of the cutoff valve 60, and the cutoff valve 60 assumes the right half position. Since this time the port l and the port i is interrupted, the overdrive direct clutch C is eliminated given which was back pressure to the port g of ₀ accumulator 54, slow engagement of overdrive direct clutch C ₀ Become. That is, the accelerator is 4-3 downshift in the state of ON, in the case of example 4-3 kickdown is engagement of overdrive direct clutch C ₀ is slow, shock at the time of downshifting is reduced.

When the accelerator is turned off, the port m of the throttle valve 53 is moved to the port of the cutoff valve 60.
The supply of the hydraulic pressure to n and p is stopped, and the oil at the ports n and p is discharged. Accordingly, the cutoff valve 60 takes the left half position, the passed port l and the port i are communicated, the overdrive direct clutch C ₀ accumulator
Back pressure is applied to the port g of 54, so that the engagement of the overdrive direct clutch C ₀ becomes faster. That is, the accelerator is 4-3 downshift in the state of off, for example in the case of 4-3 manual-down is faster engagement of overdrive direct clutch C _0, the response at the time of downshifting becomes better.

As described above, it is switched cutoff valve 60 by the accelerator ON and OFF, the shift down the supply of back pressure applied to the overdrive direct clutch C ₀ accumulator 54 along with it combined the control has been running condition The control is performed, but the speed naturally shifts down from 4th to 3rd while lowering speed 4-3
At the time of coast down, it is desirable to reduce the shock as at the time of kick down. Therefore, when the 4-3 coast down, the back pressure of the overdrive direct clutch C ₀ accumulator 54 is removed.

For this purpose, a linear solenoid valve 51 that operates at the time of 4-3 coast down is used for controlling the accumulator control valve 58. That is,
The port r of the linear solenoid valve 51 is connected to the port q of the accumulator control valve 58,
When the linear solenoid valve 51 is operated and hydraulic pressure is supplied to the port q, the accumulator control valve 58
Moves to the right half position, and ports k and j are shut off. As a result, the back pressure formed on the port j side can be forcibly removed.

The cut-off valve 60 is provided with a port n and a port p which are branched from one oil path. This is for giving the cut-off valve 60 a snap action. In order to form the snap action, the pressure receiving area of the land 69 of the spool valve is made larger than the pressure receiving area of the land 70. Therefore, the oil is initially supplied from the port n and the port p with the accelerator being turned on. At that time, the oil supplied from the port n pushes the land 69 down, but the oil supplied from the port p
Since the pressure is applied to 70 and the spool valve is urged upward from the difference in the pressure receiving area, the speed at which the spool valve descends is low. When the supply of oil from the port p is stopped during the descent, the force for urging the spool valve upward disappears, and the oil supplied from the port n exclusively pushes the land 69 downward. The descent speed becomes faster.

Conversely, when the spool valve rises, a snap action is similarly given, and the speed increases in the latter half of the rise.

As described above, since a reliable switching operation can be obtained at the time of descending and ascending, the overdrive direct clutch
Supply and stop of the back pressure against the C ₀ accumulator 54 becomes faster.

According to the present invention, in the hydraulic control system configured as described above, the electronic control device 3 is connected to and driven by the solenoid of the linear solenoid valve 51 described above. Thereby,
Short-circuit failure between the solenoid terminals of the linear solenoid valve 51 can be reliably detected.

As a result, when a short-circuit failure is detected, the mode shifts to a mode in which manual shifting can be performed by operating the shift lever (a so-called emergency mode), fail-safe control is performed, and the failure warning device 17 attached to the instrument panel in the driver's seat is activated. It can be activated to alert the driver of a malfunction and warn of the need for repair.

In addition, by storing the occurrence of the short-circuit failure in the memory of the electronic control unit, a dealer or the like can read out the short-circuit failure using a diagnostic system or the like, thereby quickly searching for a failure location, and providing a service. Performance can be improved.

It should be noted that the present invention is not limited to the above embodiments, and various modifications are possible based on the gist of the present invention, and they are not excluded from the scope of the present invention.

[Brief description of the drawings]

1 is an overall configuration diagram of an electronically controlled automatic transmission to which the present invention is applied, FIG. 2 is an interface circuit diagram of a linear solenoid of the transmission, and FIG. 3 is a monitor voltage characteristic diagram of the linear solenoid in a normal state. FIG. 4 is a monitor voltage characteristic diagram when the terminals of the linear solenoid are short-circuited, and FIG.
FIG. 6 is a diagram showing experimental data when the linear solenoid of the present invention is short-circuited between terminals. FIG. 6 is a flowchart of failure detection when the linear solenoid is short-circuited between terminals. FIG. 7 is a specific automatic transmission of the present invention. FIG. 8 is a diagram showing a first application example to a hydraulic control device, and FIG. 8 is a diagram showing a second application example to a specific hydraulic control device of an automatic transmission according to the present invention. 1 ... Throttle sensor, 2 ... Vehicle speed sensor, 3 ... Electronic control device, 4,5 ... Interface circuit, 6 ... Microcomputer, 7 ... First shift solenoid drive circuit, 8 ... Second Shift solenoid drive circuit, 9 ...
Lock-up solenoid drive circuit, 10 hydraulic drive solenoid drive circuit, 11 monitor circuit, 12 first shift solenoid, 13 second shift solenoid, 14
... lock-up solenoid, 15 ... solenoid for hydraulic control (linear solenoid), 16 ... drive circuit for failure warning device, 17 ... failure warning device, 23, 51 ... linear solenoid valve.

Continuation of the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) F16H 59/00-63/48 F16K 31 / B60K 41 / F02D 41 /

Claims (3)

(57) [Claims] An electronic control type automatic transmission having a linear solenoid for performing feedback control by an electronic control unit, wherein a deviation between a target value of an electric quantity between terminals of the linear solenoid and a measured value of an actual electric quantity is sampled. And a means for executing the sampling a predetermined number of times to obtain the sum of each sampling, and a means for comparing the sum with a reference value, based on the result of the comparison, determining whether there is a short between the terminals of the linear solenoid. A control device for an electronically controlled automatic transmission, characterized in that: 2. A control device for an electronically controlled automatic transmission according to claim 1, wherein said target value is set after shifting to a stable state. 3. The control device for an electronically controlled automatic transmission according to claim 1, wherein the determination is not performed when the deviation exceeds a set value.