JPH02203064A - Electronically controlled automatic transmission - Google Patents

Abstract

PURPOSE:To prevent generation of a fault and an abnormal shock by setting the priority respectively in a clutch and a brake and changing engagement/non- engagement of the clutch and the brake by an electronic control means in accordance with this priority. CONSTITUTION:A turbine shaft 600 and an output shaft 605 coaxially arrange an overdrive mechanism 607 consisting of a single pinion type planetary gears and a gear speed change mechanism 608 consisting of a double pinion type planetary gears, obtaining a forward 4-speed (with overdrive) shift and a reverse 1-speed shift by selectively engaging clutches C0 to C2 and brakes B0 to B2. Here an electronic control means, additionally providing the priority of the clutches C0 to C2 and the brakes B0 to B2, for instance, in the order of the clutch C2 and the brakes B0 to B2 with the clutch C0 in the first priority, performs a control from the lower priority. Thus, whatever speed change may be performed, generation of an abnormal shock and a fault can be prevented halfway a speed change.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to an electronically controlled automatic transmission installed in a vehicle.

(Prior Art) Conventionally, in an automatic transmission system for a vehicle, a clutch or a brake within the automatic transmission is operated by changing the oil pressure of a hydraulic circuit at the time of shifting, thereby changing gears. The hydraulic circuit is
It has a shift valve that operates for each shift depending on the movement of the shift lever, throttle distance, and vehicle speed. for example,
In a 4-speed automatic transmission, the shift valves include a 1-2 shift valve, a 2-3 shift valve, and a 3-4 shift valve. The output of each shift valve operates multiple clutches and brakes of the automatic transmission through a timing valve and an accumulator.

On the other hand, there is a control device that independently controls each clutch and brake in an automatic transmission using corresponding shift valves. The operation of each shift valve is controlled by a solenoid valve, and the solenoid valve is controlled by a computer. In this device, 1. Since each clutch and brake can be controlled independently, it is possible to perform control that suits the driving conditions, improving performance.

(Problem to be Solved by the Invention) However, in this device, for example, when a jump shift from 1st to 3rd gear occurs, the 1-2 shift and 2-2 shift occur.
Three gears may be controlled simultaneously, and there is a risk that an abnormal engagement state of the automatic transmission may occur during the gear shifting process.

Therefore, the technical object of the present invention is to prevent failures and abnormal shocks from occurring in the automatic transmission even when a skip shift occurs.

[Structure of the invention]

(Means for Solving the Problems) The technical means used in the present invention to solve the above problems includes a plurality of clutches and brakes that are operated by application of fluid pressure, and the engagement and operation of the clutches and brakes. an automatic transmission that changes a gear ratio when disengaged; a fluid pressure switching device that controls the application of fluid pressure to the clutch and the brake; and a fluid pressure switching device that drives the fluid pressure switching device depending on the running state of the vehicle, and and brake engagement/
In an electronically controlled automatic transmission including an electronic control means for changing disengagement, the electronic control means sets priorities for the clutch and the brake, respectively, and controls the clutch and the brake according to the priority. The purpose is to change engagement/non-engagement.

(Operation) According to the technical means described in L, priority is set for the clutch and the brake, so that no matter what kind of gear change occurs, another gear stage will not be formed during the gear change.

(Example) Hereinafter, an example using the present invention will be described based on the drawings. In this embodiment, a 4-speed automatic transmission (with overdrive) is used as the automatic transmission body.

The operation of this automatic transmission will be explained with reference to FIG.

A turbine shaft 600, which is the human power shaft of the overdrive mechanism 607, is connected to the engine via a torque converter. This turbine shaft 600 is connected to a carrier 609 of a planetary gear system. A planetary pinion 610 rotatably supported by a carrier 609 is connected to an input shaft 611 of a gear transmission mechanism 608 via an OD planetary gear 601. Also planetary binion 61
0 is meshed with sun gear 612. sun gear 612
An OD brake BO is provided between the housing 613 and the housing 613. A forward clutch C1 is provided between the input shaft 611 and the intermediate shaft 614 of the gear transmission mechanism 608. Further, a direct clutch C2 is provided between the input shaft 611 and the sun gear shaft 615. A second brake B1 is provided between the sun gear shaft 615 and the housing 613. A planetary binion 619 rotatably supported by a carrier 617 connected to the output shaft 605 is connected to the intermediate shaft 614 via a gear and a carrier 618.

Further, the planetary binion 619 meshes with the sun gear shaft 615. Planetary binion 621 is carrier 6
17 and sun gear shaft 615. 1 between the planetary binion 621 and the housing 613
s t, and Rev brake B2 is provided.

In this automatic transmission, clutches CO and CI.

The relationship between C2, brakes BO, Bl, and B2 and the gears is as shown in the table below.

O: Engaged ×: Disengaged Table 1 This clutch Co, CI, C2 and brakes BO, B
1 and B2 are controlled in their engagement and release by the hydraulic circuit shown in FIG.

Referring to FIG. 2, a hydraulic pump 70 is connected to an oil reservoir 701.
The hydraulic oil pumped up by the line pressure oil passage 704
is supplied to The pressure regulating valve 703 controlled by the line pressure control solenoid valve 48 is connected to the line pressure oil passage 704.
Adjust the oil pressure.

Line pressure oil passage 704b is connected to line pressure oil passage 704 via pressure regulating valve 703, but clutch C01#
+ Solenoid valve 41 for t1411. Clutch 02 control solenoid valve 42. Brake BO control solenoid valve 43. Brake 81 control solenoid valve 44. Manual valves 705, 706, 707, respectively via the brake B2 control solenoid valve 45.
708 and 709. Further, the output of the hydraulic pump 702 is directly connected to the manual valves 705, 706, 707, 708, and 709. The outputs of manual valves 705, 706, 707, and 708 are clutch CO, clutch C2, and brake B, respectively.
O, brake B1 is connected. The output of manual valve 709 is connected to brake B2 via valve 710. valve? 10 is connected to a shift valve 711 via a solenoid valve 46 for inhibiting low and reverse.

Shift valve 711 is also connected to manual valve 706. This shift valve 711 moves in response to the operation of the shift lever, and hydraulic pressure from the hydraulic pump 702 is applied to the inside of the shift valve 711 when the shift valve 711 is in a position other than the P range. Furthermore, oil pressure is applied to the clutch C1 during 1st, 2nd, 3rd, and OD. And L
When in the 2 range, hydraulic pressure is supplied to the manual valve 706, and when in the L and R ranges, hydraulic pressure is supplied to the low and reverse prohibition solenoid valves 46.

With this configuration, when the clutch 02 control solenoid valve 41 is opened, the manual valve 705 moves, the output of the hydraulic pump 702 is applied to the clutch CO, and the clutch CO is engaged. Clutch CO? When the trlltl solenoid valve 41 is closed, no hydraulic pressure is applied to the clutch CO, and the clutch CO is released.

Clutch C1 is engaged by applying hydraulic pressure during 1st, 2nd, 3rd, and OD, and is released without applying hydraulic pressure during other ranges.

In the clutch C2, when the clutch 02 control solenoid valve 42 is opened, the manual valve 706 is moved, hydraulic pressure is applied to the clutch C2, and the clutch CO is engaged. If the clutch 02 control solenoid valve 42 is closed, no hydraulic pressure is applied to the clutch C2, and the clutch C
2 is released. However, due to the shift valve 711, 2
When in the range mode, hydraulic pressure is supplied to the manual valve 706, and the hydraulic pressure to the clutch C2 is cut off regardless of the movement of the clutch C2 control solenoid valve 42.

In the brake BO, when the brake BO control solenoid valve 43 is opened, the manual valve 707 moves, oil pressure is no longer applied to the brake BO, and the brake BO is released. When the solenoid valve 43 for controlling the brake 32 is closed, hydraulic pressure is applied to the brake BO, and the brake BO is engaged.

In the brake B1, when the solenoid valve 44 for controlling the brake 81 is opened, the manual valve 708 is moved, hydraulic pressure is no longer applied to the brake B1, and the brake B1 is released. When the solenoid valve 44 for controlling the brake 32 is closed, hydraulic pressure is applied to the brake Bl, and the brake Bl is engaged.

In the brake B2, when the solenoid valve 45 for controlling the brake 32 is opened, the manual valve 709 moves, oil pressure is no longer applied to the brake B2, and the brake B2 is released. When the brake B2 control solenoid valve 45 is closed, the brake B2 is controlled via the valve 710.
Hydraulic pressure is applied to the brake B2, and the brake B2 is engaged. However, when the low and reverse prohibition solenoid valves 46 are turned on in the R range and the HI range, hydraulic pressure is applied to the valve 710, cutting off the supply of hydraulic pressure to the brake B2.
Release brake B2.

In other configurations, reference numeral 712 is a lock-up control valve, and when the lock-up control solenoid valve 47 is turned on, the output shaft of the engine and the turbine rotation shaft 600 are directly connected to enter a lock-up state.

Each solenoid valve is driven by an electronic control circuit, which will be described later, and the clutches and brakes are controlled so that the relationships shown in Table 1 are achieved according to the driving conditions.

Further, each solenoid valve is repeatedly turned on and off at a relatively high frequency by an electronic control circuit to be described later, and by controlling the duty ratio, the opening degree of each manual valve can be adjusted. When the duty ratio is increased, the manual valve opens wide and the hydraulic pump 702
The hydraulic pressure generated by this is quickly applied to each clutch and brake, increasing the operating speed of each clutch and brake.

Further, when the duty ratio is lowered, the opening degree of the manual valve becomes smaller, and it takes time for the hydraulic pressure generated by the hydraulic pump 702 to reach each clutch and brake, and the operating speed of each clutch and brake becomes slower. Therefore, by controlling the duty ratio, the operating speed of each clutch/brake can be adjusted, reducing the shock that occurs when each clutch/brake is engaged, and improving transmission efficiency.

FIG. 3 shows an electronic control circuit that drives each solenoid valve in the hydraulic circuit.

An input end of a constant voltage power source 22 is connected to a terminal of a battery 20 mounted on the vehicle via an ignition switch 21. The output terminal of the constant voltage power supply 22 is connected to the power supply terminals VCC and GND of the central processing unit CPU. The constant voltage power supply 22 is for converting the output voltage of the battery 20 into a voltage at which the central processing unit CPU can operate.

Each input terminal of the CPU (central processing unit) is connected to an engine rotation sensor 23. Turbine rotation sensor 24 Output shaft rotation sensor 25. Throttle sensor 26° Neutral start switch 27. An idle switch 32 and a brake switch 33 are connected. In FIG. 3, the input interfaces of each sensor and switch are omitted for simplicity.

The engine rotation sensor 23 is a sensor that detects the rotation speed of the vehicle engine. The engine rotation sensor is disposed near the output shaft of the engine, and outputs a pulse signal having a frequency corresponding to the engine rotation speed.
The engine rotation sensor is an electromagnetic pickup type rotation sensor installed opposite the teeth of the ring gear attached to the output shaft of the engine.
Outputs 0 pulse. This output is the central processing unit cp
sent to u.

The turbine rotation sensor 24 is a sensor that detects the rotation speed of the turbine. The turbine rotation sensor is disposed near the turbine rotation shaft and outputs a pulse signal having a frequency corresponding to the rotation speed of the turbine. In this embodiment, the turbine rotation sensor is an electromagnetic start-up type rotation sensor installed opposite the teeth of a gear attached to the turbine shaft 600, and outputs 57 pulses for one rotation of the gear.

This output is sent to the central processing unit hCPU.

The output shaft rotation sensor 25 is a sensor that detects the rotation speed of the output shaft of the automatic transmission. The output shaft rotation sensor is disposed near the output shaft of the automatic transmission, and outputs a pulse signal having a frequency corresponding to the rotation speed of the output shaft of the automatic transmission. In this embodiment, the output shaft rotation sensor is an electromagnetic pickup type rotation sensor installed opposite the teeth of a gear attached to the output shaft, and outputs 18 pulses for one rotation of the gear. This output is sent to the central processing unit (CPU). Note that the output shaft rotation sensor may be replaced with another type of vehicle speed sensor that detects the speed of the vehicle, as long as the relationship between the output shaft of the automatic transmission and the rotational speed of the wheels is clearly known.

The throttle sensor 26 is a sensor that detects the opening degree of the throttle valve of the engine. The throttle sensor includes a digital 2-mechanical throttle sensor that detects the rotation angle of the throttle valve using a switch and divides the opening of the throttle valve, and converts the rotation angle of the throttle valve into a voltage value. There are analog and electric throttle sensors that use an A/D converter to divide the throttle valve opening. In the present invention, both throttle sensors are provided and used selectively, but in a normal device, only one of them may be used. The throttle sensor outputs a signal obtained by dividing the opening degree of the throttle valve into 16 parts from four signal lines. Fully closed state is θ0.
The fully open state is set to 015. Between θO and B15 is θ1~θ
14.

The neutral start switch 27 detects the position of the shift lever, and is a D (drive) range switch and an L (low) range switch.

2 (second) range switch, 3 (third) range switch, neutral to N) range switch, R (
It has a reverse (reverse) range switch and a P (parking) range switch, and detects the D, L, 2°3, N, R, and P ranges.

The idle switch 32 is a sensor that detects the idle state of the engine, and its contact is turned ON when the engine is idle (in this embodiment, the throttle opening is 1.5% or less).

The brake switch 33 detects whether the brake is on or off.

A clutch C is connected to each output terminal of the CPU (central processing unit).
O control solenoid valve 41. Clutch 02 control solenoid valve 42. Brake BO control solenoid valve 43. Brake 81 control solenoid valve 44.
Brake 82 control solenoid valve 45. Solenoid valve for inhibiting low/reverse shift 46. A solenoid valve 47 for lock-up control and a solenoid valve 48 for line pressure control are connected. In FIG. 3, the output interface or drive device for each solenoid is omitted for simplicity.

Clutch CO control solenoid valve 41. clutch 0
2 control solenoid valve 42. Brake BO control solenoid valve 43. Brake B1 control solenoid valve 44. Brake B2 control solenoid valve 45.
Solenoid valve for inhibiting low/reverse shift 46. The lock-up control solenoid valve 47 and the line pressure control solenoid valve 48 are each controlled by a central processing unit (CPU).

The central processing unit (CPU) has internal memories such as RAM and ROM, timers, and registers, and when the ignition switch is turned on, the central processing unit (CPU)
When voltage begins to be supplied to , the main routine shown in FIG. 4 begins to be executed.

Figure 4 shows the main routine 2 of the central control unit CPtJ.
It is a flowchart of a vehicle speed sensor interrupt, a turbine rotation sensor interrupt, an engine rotation sensor interrupt, and a fixed time interrupt.

(Main Routine) When the central control unit CPU starts, it first sets the input/output direction of each input/output board, initializes each memory, and sets the presence/absence of interrupts (step 50).
).

After that, an input/output reading routine is executed to read the status of each sensor and switch connected to the input, remove noise, and set data according to the status of each sensor and switch (step 51).

Next, a rotational speed calculation processing routine is executed to calculate the vehicle speed, turbine rotational speed, and engine rotational speed (step 52).

The engine rotation speed NE is calculated using the following formula.

Note that since the output from the engine rotation sensor has a high frequency, it is calculated after dividing the frequency by eight.

N! ! -(nE(i-1)+n[!i)/2nE
i = (PCEi /TEi) × (8 frequency division / 8xlO-')
: Time count to the edge of the first pulse exceeding 1015 from the previous pulse, PC[! i: number of pulses during TEi, 5xxo-”
: The minimum unit of detection time (8 μs).

Calculation of the turbine rotation speed NT is performed using the following formula.

Note that since the output from the turbine rotation sensor has a high frequency, the frequency is divided by four before calculation.

NT = (nT(i-1)+nTi) / 2nT
i= (PCTi /TTi) × (4 frequency division / 8 × 10-')
: Time count until the edge of the first pulse exceeding 10 m5 from the previous pulse, PCTi : Number of pulses during TTi.

Calculation of the output shaft rotation speed NO is performed using the following formula.

No = (nO(i-1) + not) / 2n
Oi = (PCOi /TOriX (1/8 X I 0-6) The time count to the edge of one pulse is PCOi x the number of pulses in TON.

Calculation of the first output shaft rotation speed No after the vehicle stops (determined in a scheduled interrupt routine to be described later) is No = (144+n0i)/2.

Since the gear ratio of the output shaft and the axle and the radius of the wheels are determined in advance, the vehicle speed can be determined from the output shaft rotational speed NO.

Next, a vehicle speed difference calculation routine for control is executed, and a vehicle speed difference for control is determined (step 53).

Next, a line pressure control/shift control routine is executed, and line pressure setting and control, control mode setting, and shift determination are performed (step 54).

The line pressure set value is set by the throttle opening and turbine rotation speed. The line pressure solenoid is duty-driven according to this setting.

In the shift control, whether or not a shift is to be determined is determined based on a shift diagram created in advance using the throttle opening, vehicle speed, and current shift position.

When the above processing is completed, next, in the line pressure control/shift control routine, it is determined that shifting is possible, and if shifting is not currently in progress, a shifting processing routine is executed, and shifting processing is performed.

Next, a lockup determination routine is executed, and if the lockup has been changed, a lockup processing routine is executed to perform lockup processing.

Next, fail-safe control is performed, and fail-safe processing is performed (step 64). Finally, the output control routine is executed and output control is performed (step 65).
.

(Interrupt routine) The outputs of the output shaft rotation sensor, turbine rotation sensor, and engine rotation sensor are each connected to the interrupt input terminal of the central processing unit CPU, and each time the voltage level of the interrupt terminal changes, the output of the output shaft rotation sensor Interrupt routine, Turvia rotation sensor interrupt routine,
An engine rotation sensor interrupt routine is executed.

In the output shaft rotation sensor interrupt routine, first, the time at the time of the interrupt is read from a timer, and then a calculation flag for calculating the output shaft rotation speed is turned on. Next, a failure of the turbine rotation sensor and the engine rotation sensor is determined.

(Steps 66-68). This failure determination is performed by comparing the output shaft rotation speed, the turbine rotation speed, and the engine rotation speed.

In the turbine rotation sensor interrupt routine, first, the time at the time of the interrupt is read from a timer, and when the interrupt is counted four times, the calculation flag for calculating the turbine rotation speed is turned on in order to divide the frequency of the human pulse by four. Then, a failure of the engine rotation sensor and the output shaft rotation sensor is determined.

(Steps 69-71). This failure determination is performed by comparing the turbine rotation speed with the engine rotation speed and the output shaft rotation speed. Note that the frequency division may be performed by installing a frequency division circuit between the central control unit CPU and the rotation sensor.

In the engine rotation sensor interrupt routine, first, the time at the time of the interrupt is read from a timer, and when the interrupt is counted 8 times in order to divide the input pulse by 8, a calculation flag for calculating the engine rotation speed is turned on. Then, it is determined whether the output shaft rotation sensor and the turbine rotation sensor are out of order.

(Steps 72 to 74) This failure determination is performed by comparing the engine rotation speed with the output shaft rotation speed and the turbine rotation speed. Incidentally, the frequency division may be performed by installing a frequency dividing circuit between the central control unit CPU and the rotation sensor.

The central control unit (UNISO) CPU has regular interrupts that occur every predetermined period of time. In this example, 4 m
A scheduled interrupt routine is executed every s. Here, first, various timers used for control are subtracted (step 75).

Next, it is determined whether the vehicle has stopped (step 76). In this example, vehicle stopping speed N5top=144rp
Vehicles must stop at a distance of less than 3 km (approximately 3 km). Also, the input frequency T s top to the central control unit CPU =
23. When there is no pulse of 13m5 or more, the vehicle is stopped.

The details of each control will be explained below based on the flowchart.

FIG. 5 is a flowchart of the line pressure control/shift control routine.

(Line Pressure Control) First, a turbine rotation range is searched from the turbine rotation speed NT. Then, line pressure is determined from the turbine rotation range and throttle opening data (steps 149 and 150). The line pressure is determined from the line pressure map shown in FIG. 8th
The line pressure map shown in the figure is obtained from actual measurements. The line pressure at which the efficiency during shifting becomes better than the actually measured value is as shown in FIG. This is converted into the line pressure map shown in FIG. From the line pressure obtained in this way, a duty value for driving the line pressure control solenoid valve 48 is calculated (
Step 151). Then, the calculated duty value is output and the line pressure control solenoid valve 48 is driven (steps 152 and 153). Thereby, the line pressure is controlled to the determined value.

(Range switching process) Next, range selection is performed. When the neutral start switch 27 is in the R range, the R shift is set to the output sofa, and the solenoid valve for controlling the line pressure is controlled by the agency so that the line pressure reaches the maximum value (steps 183 to 185).

When the neutral start switch 27 is in the N range, N shift is set in the output buffer (step 18).
6.187).

Neutral start switch 27 is in R range.

When the range is other than N, in steps 193 to 197, the range map for each range is selected.In the 3-range map, there is no 3→4 up line, and in the 2-range map, there is no 2→4 up line.
There is no 3, 3 → 4 up line, and 1 → 2 on the L range map.
, 2-3.3-4 There is no up line.

(Shift control) Next, a gear stage is set based on the determined shift diagram. First, load the current output memory stage. When this output memory stage is not 4th and the current vehicle speed is larger than the upshift vehicle speed determined from the throttle opening and the current output memory stage, the upshift flag is turned on to shift up, and the next shift stage is output to the output buffer. and is set in the output memory (steps 201 to 206). If the current output memory stage is 4 th (0/D), or if the current vehicle speed is less than or equal to the shift-up vehicle speed in step 204, the current output memory stage is not 1st, and the throttle opening is When the current vehicle speed is smaller than the downshift vehicle speed determined from the current output memory stage, the up/down flag is turned on to shift down, and the next shift stage is set in the output buffer and output memory (steps 202, 204, 206). , 208-211). If the current output memory stage is 4 th (0/D), or if the current vehicle speed is less than or equal to the upshift vehicle speed in step 204, and the current output memory stage is 1st or the current vehicle speed is When the vehicle speed is high, the next shift stage is set in the output sofa and output memory (steps 202, 204, 206, 208 to 211
).

If the timer TON, which is a timer for prohibiting multiple speed changes during a speed change, has not expired, the change solenoid valve for speed change is selected and the speed change permission flag is turned on.

When the timer TON has ended, the shift permission flag is turned off (steps 221 to 224), so that no new shift is performed when determining a shift during a shift other than when the timer TON is running. This is to prevent a delay in the gear shifting operation when gear shifting decisions occur consecutively in a short period of time. When the timer TON ends, even if the gear is being changed, if there is a new gear change determination, the next gear change process will be performed from that point onwards. Incidentally, the timer TON is started during the speed change processing at step 57 in FIG.

When the above processing is completed, the process returns to the main routine.

(output control routine) FIG. 6 is a flowchart of the output control routine.

When the shift permission flag is turned on, first, the shift permission flag is cleared, and the shifting flag is set (steps 288 to 290). Next, priority processing is performed when it is necessary to operate a plurality of clutches and brakes on the disengagement side and on the engagement side when changing gears. For example, if a jump shift occurs from 2nd gear to 4th gear (0/D),
Referring to Table 1, from engagement to disengagement of clutch CO,
It is necessary to shift the clutch C2 from disengagement to engagement, the brake BO from disengagement to engagement, and the brake Bl from engagement to disengagement. Therefore, clutch C2 and brake BO are engaged, and clutch CO and brake Bl are released. At this time, if the brake BOO is engaged before the brake Bl is released, as shown in FIG. 1, the sun gear shaft 615 and the shaft 620 of the planetary pinion 621 are fixed to the housing 613, so the carrier 617 is It is fixed, and the output shaft 605 does not rotate. In this case, the vehicle may be braked suddenly, leading to an accident or damage to the automatic transmission and peripheral devices. Therefore, brake B1 must be released before brake BO is engaged. In this way, when changing gears, when a plurality of clutches or brakes are released or a plurality of clutches or brakes are engaged, it is important which clutch or brake is operated first. In this embodiment, as shown in Tables 3 and 4, the clutches or brakes to be operated each time the gear is shifted are prioritized. Table 3 shows the upshift, and Table 4 shows the downshift.

1JL Table 1 The priority order is as follows: Clutch CO has the highest priority, and clutch C2
, brake BO, brake Bl, and brake B2 are added in this order. Control is performed starting from the lowest priority.

The contents of Tables 3 and 4 above are stored in the central processing unit CPU.

Referring again to FIG. 6, when the shift permission flag is on, after the flag processing is completed, the table 3 and the table 3 which stores the second clutch or brake on the release side from the current shift gear and timing shift gear are displayed. Read from the contents of Table 4. If there is a second order clutch or brake, the duty ratio of the solenoid corresponding to the second order clutch or brake is set to 0%.

That is, output to turn off (steps 291 to 293
). Thereafter, the clutch or brake in the first order on the release side is activated one after another (step 294). Similarly, read out the second clutch or brake on the engagement side, and
If there is a clutch or brake in the second rank, set the duty ratio of the solenoid corresponding to the second clutch or brake to 100%1.
That is, output to turn on (steps 295 to 297
).

Thereafter, the first clutch or brake on the engagement side is engaged (step 298). In this way, if a clutch or brake with a lower priority exists at the start of a shift, it is engaged or released first.

After this process, or if the shifting flag is set, the process for the first clutch or brake is performed. First, it is determined whether it is a downshift or an upshift by referring to a flag, and downshift processing (step 302) and amplifier shift processing (step 303) are performed, respectively. To explain the outline of this downshift processing and upshift processing, first, after a time T0, 2 seconds after the shift decision (shift permission flag is turned on), the first clutch or brake on the release side is released (duty ratio 0%).
be done. While monitoring the subsequent change in engine speed, the duty ratio for applying the engagement state of the first clutch or brake on the engagement side to the solenoid valve is gradually changed. When the duty ratio reaches 100% or when the engine speed reaches a value expected after the shift, the shifting flag is cleared and the shift is completed.

The above processing will be explained by giving one example with reference to FIG.

For example, if the current shift I stage is l s t and the timing shift stage is 4 th (0/D), refer to Table 3 showing the upshift priority order and select the first shift stage on the release side. The order is clutch CO1, the second order is brake Bl, and the first on the engagement side.
The order of priority is clutch C2, and the second order is brake BO.

Therefore, after determining the gear shift, first, the brake B1, which is the second priority on the release side, is released, and the brake BO, which is the second priority on the engagement side, is engaged. The first clutch CO on the disengagement side takes a time T from the shift judgment. Released after FF. At this time, the automatic transmission is in neutral, so the engine speed increases slightly. The engagement ratio of clutch C2, which is the first order of engagement, is controlled while monitoring the state of the engine speed. As the engagement of clutch C2 progresses, the engine speed decreases. When the engagement of clutch C2 reaches 100%, the shift ends, and the automatic transmission shifts to 4th gear (0/D). become a state.

〔Effect of the invention〕

As explained above, the present invention includes a plurality of clutches and brakes operated by application of fluid pressure,
an automatic transmission that changes gear ratios by engaging and disengaging the clutch and brake; a fluid pressure switching device that controls application of fluid pressure to the clutch and brake;
Driving the fluid pressure switching means according to the running state of the vehicle,
In an electronically controlled automatic transmission including an electronic control means for changing engagement/disengagement of the clutch and brake,
No matter what kind of gear shifting occurs, no abnormal shock occurs during gear shifting or failure of the automatic transmission occurs.

[Brief explanation of the drawing]

FIG. 1 shows an automatic transmission of an electronically controlled automatic transmission which is an embodiment of the present invention. FIG. 2 shows a hydraulic circuit for driving the automatic transmission of FIG. FIG. 3 shows an electronic control circuit that controls the hydraulic circuit of FIG. FIG. 4 is a flowchart of the main routine of the CPU of the electronic control circuit of FIG. 3, a vehicle speed sensor interrupt, a turbine rotation sensor interrupt, an engine rotation sensor interrupt, and a scheduled interrupt. FIG. 5 is a flowchart of the CPU line pressure control/speed change control routine of the electronic control circuit of FIG. FIG. 6 is a flowchart of the output control routine of the CPU of the electronic control circuit of FIG. FIG. 7 is a time chart 1 showing an example of control of the electronic control circuit of FIG. 3 during speed change of the CPU. FIG. 8 is a line pressure map of the CPU of the electronic control circuit of FIG. FIG. 9 is a graph showing the relationship between turbine rotation speed and line pressure. CPU... central processing unit, 20... battery, 21... ignition switch, 22 ・ 23 ・ 24 ・ 25 ・ 26 ・ 27 ・ 32 ・ 33 ・ 41 ・ 42 ・ 43 ・ 44 ・ 45 ・ 46・B、47・48・B2・C2・B1・・Constant voltage power supply,・Engine rotation sensor・Turbine rotation sensor・Output shaft rotation sensor・Throttle sensor・Neutral start switch,・Idle switch,・Brake switch,・Clutch C2 Control solenoid valve, clutch C
2 control solenoid valve, ・Solenoid valve for brake 81 control, ・Solenoid valve for brake 81 control, ・Solenoid valve for brake B2 control, ・Solenoid valve for low and reverse prohibition solenoid pulse lockup control, ・Solenoid valve for line pressure control Solenoid valve, -1st and Rev brake, ・Direct clutch, ・Second brake, CO・・BO・・C1・・600・601・605・607・608・609°610, N, 611・612・613・614・615・ 701 ・ 702・ 703・ 704・ ・OD clutch, 7chi, ・OD brake, ・Forward clutch, ・・Turbine shaft, ・・OD planetary gear, ・・Output shaft, ・・Overdrive mechanism, ・・Gear Transmission mechanism, 617.618...Kiyaria, 619.621...Planetary binio...human power shaft, ・Sun gear, ・Housing, ・Intermediate shaft, ・Sun gear shaft, ・Oil sump, ・・Hydraulic pump, ・Pressure adjustment valve, ・Line pressure oil line, 05゜706゜07゜08゜manual valve, ・Valve, shift valve, ■ ・Lockup control valve.

Claims (1)

[Claims] An automatic transmission having a plurality of clutches and brakes operated by application of fluid pressure and changing gear ratios by engaging/disengaging the clutches and brakes, and controlling application of fluid pressure to the clutches and brakes. An electronically controlled automatic transmission comprising: a fluid pressure switching means; and an electronic control means for driving the fluid pressure switching means and changing engagement/disengagement of the clutch and brake according to the running state of the vehicle. An electronically controlled automatic transmission device, wherein the electronic control means sets priorities for each of the clutches and brakes, and changes engagement/disengagement of the clutches and brakes according to the priorities.