JPS63190957A - Controller for automatic transmission - Google Patents

Abstract

PURPOSE:To keep off the worsening of drivability in case of abnormal action in a processing circuit happening, by constituting it so as to have a transmission selected to a high-speed gear ratio irrespective of contents of the shift command outputted out of the processing circuit when detecting the abnormal action in the circuit of a central processing unit or the like. CONSTITUTION:When a central processing unit 1 comes into such an abnormal action state that it fails to generate a high level pulse out of an output port P01 even if the specified time elapses since the last generation, terminal voltage of a condenser 13 goes beyond the partial voltage. With this, an output level of an operational amplifier 6 is reversed to the low level from the higher one, whereby an output level of an AND circuit 35 also comes to the low level. Since this low level makes transistors 21 and 22 come off, a current supply to solenoids 37a and 38a is stopped. Therefore, these solenoids 37a and 38a comes into a state of being magnetized, so that even if a high level signal is outputted out of an output port P03 or P04, it comes to a change gear ratio of fourth gear speed. Accordingly drivability is preventable from growing worse.

Description

[Detailed description of the invention] skin hill light 1 The present invention relates to a control device for an automatic transmission.

In automatic transmissions, one or more solenoids are provided, and when a voltage is applied to the solenoid, the solenoid is energized, thereby engaging or disengaging the clutch and changing the gear ratio. There is something composed of Voltage is selectively applied to the solenoid from the control device, and the control device detects driving parameters such as vehicle speed and throttle valve opening of the engine, and adjusts the gear ratio determined from the gear shift pattern in response to the detected values. A gear change command that specifies the

The solenoid is energized or demagnetized by turning on and off switching elements etc. according to the contents of the speed change command. Some such control devices are constructed from a processing circuit such as a CPU, and the processing circuit generates a speed change command by carrying out an arithmetic operation according to a predetermined program.

Incidentally, such a processing circuit may operate abnormally due to ignition noise of a vehicle engine or the like. For example, the program may skip over several steps or become unable to escape from a loop within the program, resulting in so-called program runaway, and it becomes impossible to recover to normal IIJ operation.

In order to prevent such abnormal operation, a step is provided in the program to generate a pulse signal (a so-called watchdog signal) at intervals of a predetermined time at most, and when the pulse signal is not generated for a predetermined time or longer, the processing circuit is Some devices are equipped with a monitoring circuit that supplies a reset signal.

However, if the processing circuit malfunctions, it may not return to normal operation even if a reset signal is supplied to the processing circuit, and in such cases, an incorrect gear shift command may occur, causing the shift of a low gear to occur at high speed. There was a problem in that the engine shifted down to a lower speed, resulting in deterioration of drivability.

1 Plate 2 Arashi 1 Therefore, the object of the present invention is to control an automatic transmission that prevents deterioration of drivability in the event of abnormal operation of the processing circuit! 1 device.

The control Vt setting of the automatic transmission of the present invention is characterized in that when an abnormal operation of a processing circuit such as a CPU is detected, the gear ratio is set to a high speed gear regardless of the contents of a gear shift command output from the processing circuit.

Friend-凰-1 Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

In the control I system of a four-speed automatic transmission which is an embodiment of the present invention shown in FIG. 1, a CPU (central processing unit) 1 consisting of a one-chip integrated circuit is provided. C.I.
) U1 is equipped with a ROM1RΔM1 clock generation circuit in which processing programs and various data are stored in advance, a timer, and a plurality of input/output capos 1-Po+ to PO5 and Pn. The output voltage of the battery 2 is stabilized and supplied to the CPLJI via a fuse 3, an ignition switch 4, and a voltage regulator 5. The output boat Po+ has an operational amplifier 6, an NPN transistor 7,
A monitoring circuit 15 consisting of resistors 8 to 11, capacitors 12, 13 and a diode 14 is connected.

In this monitoring circuit 15, the output port P is connected to the base of the transistor 7 via a capacitor 12 and a resistor 8. The diode 14 is connected between the connection line of the capacitor 12 and the resistor 8 and the ground, and cuts the negative level component in the output signal of the capacitor 12. The emitter of the transistor 7 is grounded, and the collector is connected to the inverting input terminal of the operational amplifier 6. The output of an integrating circuit consisting of a resistor 9 and a capacitor 13 that integrates the output voltage of the voltage regulator 5 is connected to this inverting input terminal. The output of a voltage divider circuit including resistors 10 and 11 is connected to the non-inverting input terminal of the operational amplifier 6. The output signal of the operational amplifier 6 is the output signal of the monitoring circuit 15, and is supplied to the mono multivibrator 16. The pulse signal output from the mono multivibrator 16 is supplied to the reset terminal of the CPU 1 as a reset signal.

Output boats PO2 to PO4 have i~Laranstar 21
to 26, resistor 27 to 32, diode 33.3
A drive circuit 36 including a cutoff circuit consisting of 4 and an AND circuit 35 is formed. The output port PO2 is connected to one input end of the AND circuit 35, and the other input end of the AND circuit 35 is connected to the output end of the operational amplifier 6. A
The output terminal of the ND circuit 35 is connected to the base of the NPN transistor 21 via the resistor 27. transistor 2
The emitter of the transistor 1 is grounded, and the collector is connected to the base of a PNP transistor 22 via a resistor 28.

This transistor 21.22, resistor 27.28 and AN
The D circuit 35 forms the M1 circuit. Out capo-h P
03 is connected to the bases of NPN1 to transistor 23 via a resistor 29.

The emitter of the transistor 23 is grounded, and the collector is connected to the base of a PNP transistor 24 via a resistor 30. A solenoid 37a is connected between the collector of the transistor 24 and ground. Out capo-l
"Similar to P Oa, the output port PO4 is connected to the base of an NPN transistor 25 via a resistor 31. The emitter of the transistor 25 is grounded, and the collector is connected to the base of a PNP transistor 26 via a resistor 32. A solenoid 38a is connected between the collector of the transistor 26 and the ground.The emitter of the transistor 22 is connected to the connection line between the ignition switch 4 and the voltage regulator 5, and the collector is connected to the emitters of the transistors 1 to 24 and 26. They are commonly connected.Solenoids 37a and 38a are provided in electric laminations 37 and 38 for hydraulic control of the automatic transmission.Diodes 33 and 34 are connected to solenoid 37 for absorbing back electromotive force.
a, 38a.

On the other hand, a pulse generator 39 for detecting vehicle speed is connected to the input port Pos of the CPU 1 via an inverter 52. The pulse generator 39 has a reed switch 53 that is turned on and off in synchronization with the rotation of the output shaft like an automatic speed change.

One end of the reed switch 53 is grounded, the other end is connected to the inverter 52, and the other end is connected to the voltage regulator 5.
An output voltage of is supplied via a resistor 54. The input boat Pa is a parallel input boat, and is connected via an A/D converter 56 to a throttle valve opening sensor 55 consisting of a potentiometer that detects the throttle valve opening of the engine.

Next, the operation of the control device having such a configuration is shown in FIG.
This will be explained according to the operation flow diagram of PU1.

When the ignition switch 4 is turned on and a power supply voltage is supplied from the voltage regulator 5, the CPU 1 enters an initial state and repeatedly processes the program written in the ROM. In the processing of the program, first, △/D
The vehicle speed information obtained from the throttle valve opening output from the converter 56 and the pulse period supplied from the inverter 52 is read (step 81), and the gear stage is searched and set from the data table (step 82).

The ROM in the cpui is preloaded with a data table of shifting patterns with characteristics as shown in Figure 3.
PU1 searches the data table for the gear position corresponding to the read throttle valve opening degree and vehicle speed. This search yields a 2-bit gear shift code from the data table, so the first bit data is sent from the output boat PO3, and the second bit data is sent from the output boat PO4 as high and low level gear shift command signals. Output each (step 83
).

Then, it is determined whether the measured value T of the timer in the CPU 1 has reached O (step 84). If T=O, a high level pulse of a predetermined width is generated from the output port Po+ (step 85), a predetermined time Ta is set in the timer, and down measurement is started (step 86). If T>O in step 84, the timer is measuring the predetermined time Ta, so steps 85 and 86 are omitted. Note that the measured value T of the timer is set to O by initialization of CP and Ul.

Since steps 84 to 86 are executed in this way, a high level pulse is generated from the output capo t.Po+ at every predetermined time Ta as shown in FIG. 4(a). This high level pulse is differentiated by the capacitor 12, and the negative level component is further cut by the diode 14, as shown in FIG. 4(b).
The trigger signal becomes a trigger signal as shown in FIG. 2, and the trigger signal turns on the transistor 7. ] - When the Ranjistaf is turned on, the charge stored in the capacitor 13 is discharged to the ground via the transistor 7, and the terminal voltage of the capacitor 13 rapidly decreases to the ground level as shown in FIG. 4(C).
In other words, it becomes approximately O■. When the trigger signal disappears, the terminal voltage of the capacitor 13 gradually rises. During normal operation of the CPU 1 in which high-level pulses are generated every predetermined time Ta, the terminal voltage of the capacitor 13 is
Since a high level pulse is generated before reaching the divided voltage Va, the output level of the operational amplifier 6 maintains a high level. Since the output capo]~1]02 is held at a high level by the initialization of the CPU 1, if the output level of the operational amplifier 6 is at a high level, a high level signal is sent from the AND circuit 35 to the base of the transistor 21 via the resistor 27. Supplied. Therefore, the l transistors 21 and 22 are turned on.

As a result of the search in step 82, if the first speed is set, the output boat PO3 indicates logic "0" and is at a low level.
Output port PO4 represents logic 11111 and is driven high, so transistor 23.24 is turned off and transistor 25.26 is turned on. From battery 2 to fuse 3, ignition switch 4, transistor 2
2.26, current flows from the solenoid 38a to the ground path, solenoid 38a is energized, and solenoid 37a
Since the transistor 24 is turned off, no current flows and it is not excited.

If the second speed is set, the output boats Poi and P
Since both O4 are pulled high, transistors 23-26 are turned on. Therefore, from the battery 2 to the fuse 3, the ignition switch 4, the transistor 22,
Furthermore, the transistor 24 and the ground from the solenoid 37a,
Furthermore, current flows from the 1-transistor 26 and the solenoid 38a through the ground path, and both the solenoids 37a and 388 are excited. When the third speed is set, the output port PO3 is set to a high level and the output port PQ4 is set to a low level, so that transistors 23 and 24 are turned on and transistors 25 and 26 are turned off. Current flows through solenoid 378, energizing solenoid 37a, and solenoid 3
Since the transistor 26 is turned off, no current flows through the transistor 8a, so it is not excited. Then, when fourth speed is set, both output ports PO3 and PO4 are brought to a low level so that transistors 23-26 are turned off. Therefore, no current flows through the solenoids 37a and '38a, and they are in a demagnetized state.

On the other hand, when the CPU 1 enters an abnormal operating state in which a high-level pulse is not generated from the output port Po+ even after a predetermined time Ta has elapsed since the previous generation, the terminal voltage of the capacitor 13 exceeds the divided voltage Va. As a result, the output level of the operational amplifier 6 is inverted from a high level to a low level as shown in FIG. 4(d), and the output level of the AND circuit 35 also becomes a low level. This low level turns off transistors 21, 22, thereby stopping the current supply to solenoids 37a, 38a. Therefore, the solenoids 37a and 38a are demagnetized, so that even if a high level signal is output from the output boat PO3 or PO4, the gear ratio is set to the fourth speed.

Further, when the operational amplifier 6 is inverted from a high level to a low level, the mono multivabrator 16 supplies a reset signal to the lipit terminal of the CPUI as shown in FIG. 4(e). When the operation of the CPU 1 is restored to normal state by this reset signal, a high level pulse is generated from the output port Po+ and the output level of the operational amplifier 6 becomes high level, so the transistors 21 and 22 are turned on, and the output port Po+ is turned on.
Solenoid 37a according to each level of Q3 and Poa.

38a is in an energized or demagnetized state. However, unless the reset signal restores the operation of the CPU 1 to its normal state, the demagnetized state of the solenoids 37a and 38a is maintained.

FIG. 5 shows a hydraulic circuit for an automatic transmission controlled by such a control device. This hydraulic circuit includes a 3-bot, 2-position manual valve 41 operated by a range select lever 40, a 3-bot, 2-position first shift valve 42 of a spring offset pilot type, and a 4-position manual valve 42 of a spring offset pilot type. Second and third shift valves 43 and 44 with one port and two positions, and a spring offset pilot type regulator valve 45 with two ports and two positions are provided as hydraulic control valves. The oil in the oil tank 46 is pressurized by a hydraulic pump 47 and discharged to the main pipe 48a. This main pipe 48a is connected to a regulator valve 45 and a manual valve 41. A main line 48b is provided between the manual valve 41 and the first shift valve 42, and the main line 48b communicates with the oil chamber of the first clutch C1. A main line 48G is provided between the first shift valve 42 and the second shift valve 43, and the second shift valve 43 is connected to the second clutch C by the main line 48d.
It communicates with the oil chamber of No.2. Further, a main line 48e is provided between the second shift valve 43 and the first shift valve 42, and the third shift valve 44 is connected to the oil chamber of the third clutch C3 through a main line 48f, and to the oil chamber of the third clutch C3 through a main line 48g. 4 It communicates with the oil chamber of clutch C4. In addition, the main pipe 48a is a pilot pipe 49a.
It is connected to 49C. A throttle 50 is provided in the pilot pipe line 49a, and a first
The shift valve 42 communicates with the boat to one pylon 1 and the pilot boat of the third shift valve 44 . The pilot conduit 49b is provided with a throttle 51, and communicates with the other pilot boat of the first shift valve 42 and the pilot boat of the second shift valve 43 on the downstream side of the throttle 51. The pilot line 49c is the regulator valve 45
It is connected to the pilot boat. The solenoid valve 37 controls the hydraulic pressure downstream of the throttle 5o in the pilot pipe 49a,
The solenoid valve 38 controls the hydraulic pressure downstream of the throttle 51 in the pilot line 49b. Note that the regulator valve 45 is provided to stabilize the oil pressure in the main pipe 48a.

In this configuration, when the travel range of the range select lever 40 is the N (neutral) range, the manual valve 41 operates in the flow direction at the right position in the figure. When the driving range is switched from the N range to the D (drive) range by operating the range select lever 40, the manual valve 41 operates in the flow direction state at the left position in the figure, and hydraulic pressure is transferred from the main pipe 48a to the manual valve 41. , is supplied to the oil chamber of the first clutch C+ via the main line 48b. When the CPU 1 sets the gear stage to the first speed by executing step 82, the solenoid valve 37 is closed by demagnetizing the solenoid 37a, and the oil pressure in the pilot pipe 49a is changed to the first and third shift #42, 44. The electromagnetic valve 38 is opened by the excitation of the solenoid 38a, and the oil in the pilot line 49b is caused to flow into the line connected to the ura tank 46, thereby lowering the oil pressure in the pilot line 49b. Therefore, as shown in FIG. 5, the first and second shift valves 4
2.43 is the third shift valve 4 in the flow direction state at the left position in the figure.
4 is in the flow direction state at the right position in the figure, and the first clutch C1
Hydraulic pressure is supplied to the oil chamber, and only the first clutch C1 is coupled.

As shown in FIG. 6, in the automatic transmission, the rotation of a crankshaft 61 is transmitted to a speed change input shaft 63 via a torque converter 62. Variable speed kashaf 1-63
are provided with oil-immersed first to fourth clutches C+ to C4, and when the first clutch C1 is coupled, the rotation of the input lever 1 shift 63 is transferred to the first clutch CI, the first gear 64,
C gear is changed through 65 and the output shirt on the rJ wheel side is 1-66.
transmitted to. Note that the gear 65 is provided with a one-way clutch 65, and the rotation of the output shaft 66 side is controlled by the gear 64.
11! It is prevented from being transmitted to l.

Further, when the gear stage is set to the second speed, the solenoid valve 37 is opened by the excitation of the solenoid 37a, and the oil in the pilot pipe 49a is caused to flow into the pipe leading to the oil tank 46. decreases the oil pressure. The solenoid valve 38 is opened by energizing the solenoid 38a, thereby reducing the oil pressure in the pilot pipe 49b as described above. Therefore, the first shift valve 42 is in the flow direction state at the right position in the figure, the second and third shift valves 43 and 44 are in the flow direction state at the left position in the figure, and hydraulic pressure is applied to the oil chamber of the first clutch C1. At the same time, hydraulic pressure is supplied to the oil chamber of the second clamp C2 via the main line 48b, the first shift valve 42, the main line 48C1, the second shift valve 43, and the main line 48d. As a result, the first and second clutches C+ and C2 are coupled, and the third and fourth clutches C3 and C4 are released. Second
When the clutch C2 is engaged, the rotation of the input shaft 63 is transmitted to the output shaft 66 on the wheel side through the second clutch C2 and the second transmission gears 68 and 69.

When the gear stage is set to the third speed, the solenoid valve 37 is opened by energizing the solenoid 37a, thereby lowering the oil pressure in the re-route conduit 9a.

(The d valve 38 is closed due to the demagnetization of the solenoid 38a, and the hydraulic pressure in the pylob 1 to the pipe 49b is changed to the first and second
Shift valves 42, 43 are supplied. Therefore, the first and second shift valves 42 and 43 are in the flow direction state at the right position in the figure, and the third shift valve 44 is in the flow direction state at the left position in the figure.
Hydraulic pressure is supplied to the oil chamber of clutch C+, and main pipe 4
8t), hydraulic pressure is supplied to the oil chamber of the third clutch C3 via the valve 42, main line 48C1, second shift valve 43, main line 48e, third shift valve 44, and main line 48f to the first shift l. . This causes the first and third clutches C1 and C3 to
are connected, and the second and fourth clutches C2 to C4 are released. When the third clutch C3 is engaged, the input shaft 6
3 rotation is the 3rd clutch C3, 3rd speed gear 70.71
The speed is changed and transmitted to the output shaft 66 on the wheel side.

Next, when the gear stage is set to 4th speed, the solenoid valve 3
7 is in a closed state due to the demagnetization of the solenoid 37a, and the oil pressure in the pilot pipe 49a is changed to M1 and the third shift valve 42.
．． 44. The solenoid valve 38 is closed due to the demagnetization of the solenoid 38a, and the hydraulic pressure in the pilot pipe 49b is supplied to the first and second shift valves 42, 43. Therefore, the first to third shift valves 42, 43, and 44 are in the flow direction state in the right position in the figure, and hydraulic pressure is supplied to the oil chamber of the first clutch C1, and the main pipe 48b1 and the first shift valve 4 are
2. Main pipe 48C1 second shift valve 43, main pipe 48e1
Hydraulic pressure is supplied to the oil chamber of the fourth clutch C4 via the third shift valve 44 and the main line 48g. This allows the first
and the fourth clutch C+, C4 are connected, and the second and third clutches C+ and C4 are connected.
Clutches C2 and C3 are released. 4th clutch C
4 is connected, the rotation of the input shift shaft 63 is changed in speed via the fourth clutch C4 and fourth gears 72 and 73, and is transmitted to the output shaft 66 on the wheel side.

In the above embodiment, when an abnormal operation of the processing circuit is detected, the gear ratio is set to the fourth gear regardless of the content of the gear change command output from the processing circuit. For example, in the case of a four-speed transmission, the gear ratio of not only the fourth speed but also the third speed may be used. The present invention can also be applied to automatic transmissions with multiple speeds other than four speeds, for example, three speeds.

Further, in the above embodiment, when an abnormal operation of the processing circuit is detected, the transistor 22 is turned off and the voltage supply to the solenoids 37a and 38a is reduced to 6%. It is also possible to provide each gate circuit and turn off the gate circuit when an abnormal operation is detected.

It is also conceivable to separately provide a solenoid excitation circuit that operates only when an abnormal operation is detected and forcibly excites the solenoid to set the high speed gear.

As described above, in the automatic transmission control device of the present invention, when abnormal operation of the processing circuit is detected, the gear ratio is set to the high speed gear, regardless of the contents of the gear shift command output from the processing circuit. Therefore, it is possible to prevent deterioration of operability in the event of abnormality in the processing circuit.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing an embodiment of the present invention, FIG. 2 is a graph diagram showing the operation of the CPU in the device shown in FIG. 1, FIG. 3 is a characteristic diagram showing a speed change pattern, and FIG. FIG. 5 is a waveform diagram showing the operation of each part of the apparatus shown in FIG. 1, FIG. 5 is a circuit diagram showing the hydraulic circuit of the automatic transmission, and FIG. 6 is a diagram showing an outline of the transmission mechanism of the automatic transmission. Explanation of symbols of main parts 1...CPU 4...Ignition switch 37.38...
...Solenoid valves 37a, 38a...Solenoid 39...
・Pulse generator 55... Throttle valve opening sensor 41... Manual valves 42 to 44... Shift valve 45... Regulator valve 47...・Hydraulic pump C1 to C4...Clutch sheath Fig. 4 (e) Fig. 5

Claims (1)

[Claims] A control device comprising: a processing circuit that generates a speed change command that specifies a speed change ratio of an automatic transmission according to running parameters of a vehicle; and a drive circuit that changes the speed change ratio according to the contents of the speed change command, the control device comprising: A control device comprising a monitoring means for detecting an abnormal operation of a processing circuit, and said drive circuit sets a gear ratio of a high speed gear when said monitoring means detects an abnormal operation, regardless of the content of said gear change command.