JPH07117142B2 - Shift control device for automatic transmission - Google Patents

Description

The present invention relates to a shift control device for an automatic transmission, and more particularly to a shift control when the power source of the automatic transmission is switched to a power-off state and then returned to a power-on state. It relates to the device.

(Prior Art) In an automatic transmission, various friction elements (clutch, brake, etc.) of a speed change gear mechanism are selectively activated to select a predetermined gear stage, and the friction element to be operated is changed to another gear stage. Shift gears.

By the way, when the power source of the automatic transmission is switched to the power-off state, for example, the engine throttle opening (TH) is changed from point X on the shift pattern (only the upshift line is shown for convenience) as shown by the solid line in FIG. When switching to fully close (release the accelerator pedal) to the point Y, the automatic transmission determines the upshift from the first speed to the second speed and performs the corresponding 1 → 2 upshift. To do. If the foot release upshift is not executed when the input rotation is in sync with the output rotation (vehicle speed) of the transmission gear mechanism in consideration of the gear ratio of the transmission, the transmission output torque is zero. Therefore, gear striking sound and rattling vibration are generated due to backlash of the differential gear.

Therefore, the applicant of the present application has previously proposed, in Japanese Patent Application No. Sho 62-282252, to perform a corresponding upshift when the gear ratio represented by the ratio between the input and output speeds of the speed change gear mechanism reaches a set value. A shift control device has been proposed.

This device functions as follows, regarding the foot release 1-> 2 upshift transmission in FIG. After the 1 → 2 upshift judgment at the instant t _{1 when} the throttle is fully closed, the engine speed N _E , the turbine speed (transmission input speed) N _{T of} the torque converter, and the transmission output speed N _O (in the drawing, The values N _O × 1.169 in consideration of the gear ratio of 1.169 after the second speed change are shown as solid lines, respectively, and the apparent gear ratio g = N _T / N _O of the transmission gear mechanism is It decreases as. From the instant t ₂ when the gear ratio g drops to the set value g _{1, the} shift solenoid A is turned off to increase the second speed selection pressure P _{2 as shown by the} solid line to perform 1 → 2 upshift gear shifting and N _T = N _O × 1 .
169, g = 1.169, and the shift is completed. Therefore, this gear shift is always executed reliably when the input speed N _T almost matches the value N _O × 1.169 in consideration of the gear ratio 1.169 after the shift with respect to the output speed N _O. Even if the output torque is zero as shown by the solid line, it is possible to prevent the generation of gear hammering noise and rattling vibration due to backlash of the differential gear or the like.

However, in such a configuration, the engine speed N _E and the turbine speed N _T are shown by the dotted line in FIG. 10 due to variations in the power source (engine) and the torque converter, changes over time, or warm-up operation of the engine. When the predetermined reduction is not exhibited as described above, the gear ratio g cannot be reduced to the set value g _{1 as} indicated by the dotted line, and the above-mentioned upshift is not executed.

By the way, after that, at an instant t ₃ in FIG. 10, when the engine is switched to the power-on state again by re-depressing the accelerator pedal from the Y point to the Z point in FIG. 9 (restarting the throttle valve), the gear ratio set value g ₁ becomes When the throttle valve is restarted, it goes up to g <g ₁ and the shift solenoid A is switched to 0FF as shown by the dotted line, and the 1st to 2nd upshift is executed by the second speed selective pressure which also rises as shown by the dotted line. Will be done.

However, the speed change is determined because the capacity of each of the various friction elements including the friction element for selecting the second speed is determined on the basis of the time when the engine output is large, or the engine speed is increased from the idling state. , It ends before the engine output rises. Therefore, the shock due to the increase of the engine output cannot be absorbed because the friction element for second speed selection has already completed the operation at this time, and the transmission output torque has a large peak torque as shown by the dotted line in FIG. It will cause a big shift shock.

The applicant of the present application actually requests re-acceleration in such a case, and since the upshift gear shift is unnecessary, the upshift gear shift is prohibited as shown in FIG. Japanese patent application Sho 63-
Proposed by No. 30977.

(Problems to be Solved by the Invention) However, in the technique of only prohibiting the upshift gear shift, for example, the foot release jump 1 → 3 upshift gear shift accompanying the switching from the x point to the y point in FIG. The case of re-depressing to the z point after the determination will be described. In this case as well, the first speed is kept as it is, and the driving feeling is inevitably deteriorated due to over-rotation of the power source.

(Means for Solving the Problem) The present invention is intended to solve this problem as well, and as shown in the concept of FIG. 1, various friction elements of the speed change gear mechanism are selectively operated to determine the shift speed. , The gear ratio is changed to another gear by changing the operating friction element, and the ratio between the input and output speeds of the speed change gear mechanism is determined after the upshift is determined due to the power source of the speed change gear mechanism shifting to the power off state. In an automatic transmission adapted to perform a corresponding upshift when the represented gear ratio reaches a set value, a timer means for measuring the elapsed time after the upshift determination and this elapsed time becomes a set time. At this time, the configuration is characterized in that a forced shift means that inserts a shift gear mechanism into a shift speed closest to the gear ratio and a shift prohibition means that prohibits an upshift shift after the forced shift are provided.

(Operation) The speed change gear mechanism selectively operates various friction elements to select a speed change step, and accelerates / decelerates the supplied power at this speed change step and outputs the power. Then, the speed change gear mechanism is changed to the speed change stage by changing the friction element to be operated.

Then, after the upshift determination due to the power source of the transmission gear mechanism shifting to the power-off state, when the gear ratio reaches the set value, the corresponding upshift shift is executed.
Therefore, if the output torque at the time of shifting is zero, it is possible to obtain shift control without causing gear hitting sound or rattling vibrations due to gear backlash.

By the way, in the state where the gear ratio does not decrease to the set value after the upshift determination and the shift is not performed, the forced shift means shifts the gear when the elapsed time after the upshift determination measured by the timing means reaches the set time. The gear mechanism is forcibly shifted to a shift stage on the low speed stage closest to the gear ratio, and the upshift shift thereafter is prohibited by the shift prohibiting means to prevent the shift shock. Therefore, even if the foot release upshift determination is an interlaced shift determination, when the set time elapses, the gear is forcibly shifted to the gear position on the lower speed side closest to the gear ratio, so that the next stepping Therefore, the over-rotation of the power source due to the prohibition of any upshift is prevented, and the driving feeling can be prevented from deteriorating.

(Example) Hereinafter, the Example of this invention is described in detail based on drawing.

FIG. 2 shows a power train control system of an automobile incorporating a shift control device of the present invention, 1 is an electronically controlled fuel injection engine, 2 is an automatic transmission, 3 is a differential gear, and 4 is a differential gear.
Is the driving wheel.

The engine 1 includes an engine control computer 5, which includes a signal from an engine rotation sensor 6 for detecting an engine speed N _E , a signal from a vehicle speed sensor 7 for detecting a vehicle speed V, and an engine throttle opening TH. The signal from the throttle sensor 8 for detecting, the signal from the intake air amount sensor 9 for detecting the engine intake air amount Q, etc. are input. The computer 5 determines the fuel injection pulse width T _P based on these input information and commands it to the engine 1, or supplies an ignition timing control signal (not shown) to the engine 1. The engine 1 is supplied with an amount of fuel according to the fuel injection pulse width T _P, and operates by burning this fuel in synchronism with the rotation of the engine.

The automatic transmission 2 was issued by Nissan Motor Co., Ltd.
4R01A automatic transmission maintenance manual "(A261C07), the torque converter 10 and the speed change gear mechanism 11 are provided in tandem, and the engine power is input to the input shaft 12 via the torque converter 10. axis
The transmission input rotation to 12 is accelerated and decelerated according to the selected gear stage of the transmission gear mechanism 11 to reach the output shaft 13, from which the drive gear 4 is passed through the differential gear 3 to drive the vehicle. .

The speed change gear mechanism 11 incorporates various friction elements (not shown) such as clutches and brakes that determine the transmission path (shift stage) from the input shaft 12 to the output shaft 13, and these various friction elements are controlled by the line pressure P _L. It is assumed that the gear is selectively hydraulically actuated to select a predetermined gear, and that the gear is shifted to another gear by changing the friction element to be actuated.

A shift control computer 14 and a control valve 15 are provided for this shift control. The computer 14 is a shift solenoid A, B for shift control in the control valve 15.
To control the shift control by selectively supplying the line pressure P _L to various friction elements so that the corresponding shift stage is selected by the combination of ON and OFF of these shift solenoids shown in the following table. .

The shift control computer 14 also controls the duty solenoid 16 for controlling the line pressure in the control valve 15 by the drive duty D to control the line pressure P _L in the control valve 15 (the line pressure increases as the duty D increases). It shall be controlled in the street. A signal from the vehicle speed sensor 7 and a signal from the throttle sensor 8 are input to the computer 14 for the shift control and the line pressure control, respectively, and a signal from an input rotation sensor 17 for detecting the rotation speed _NT of the shaft 12 and A signal from an output rotation sensor 18 that detects the rotation speed N _O of the shaft 13 and a signal I _d from an idle switch 19 that is turned on when the accelerator pedal of the engine 1 is released (TH = 0) are input.

The computer 14 executes the control programs shown in FIGS. 3 to 6 to perform normal shift control and shift control according to the present invention.

First, to explain the main routine of FIG. 3, which is repeatedly executed by a timed interrupt every 10 msec, for example, steps 21, 2
In 2, the vehicle speed V, the throttle opening TH, the input speed N _T and the output speed N _O are read, and in step 23 the speed change gear mechanism 11 is read.
The gear ratio g = N _T / N _O is calculated. In step 24, the ninth
The gear position is determined from the vehicle speed V and the throttle opening TH based on the table data (however, the 2 → 1,3 → 2,4 → 3 downshift lines are omitted) corresponding to the gearshift pattern shown by the solid line in the figure. In step 25, it is determined whether or not a shift is necessary depending on whether or not the determined shift speed is different from the currently selected shift speed.

If gear shifting is not required, shift solenoids A and B O
A determination is made to maintain the current gear without switching N and OFF, and in step 27, a solenoid drive signal is output to the shift solenoids A and B in accordance with this determination. In step 28,
When the shift line shown by the solid line in FIG. 9 is changed as shown by the dotted line, it is checked whether the flag FLG which becomes 1 as described below is 1 or not, and if FLG = 1, the shift line is set at step 29 in FIG. After returning from the dotted line to the original position shown by the solid line, and resetting FLG = 0 to indicate this in step 30, step 27 is executed, and if it is determined in step 28 that FLG ≠ 1, the shift line is changed. If not, step 27 is suddenly executed.

If a gear shift is necessary, first, in step 31, it is identified what speed the gear shift is from the currently selected gear, and in the next step 32, it is checked whether or not gear shift is already in progress, that is, whether or not after gear shift determination.
Before the shift determination, the timer T for measuring the elapsed time after the shift determination is reset in step 33, and after the shift determination, the timer T is incremented in step 34 to measure the elapsed time after the shift determination.

In step 35, it is checked whether or not the measured time of the timer T is equal to or longer than the set time T _S, and if T <T _S, step 3
Normal shift control is performed by 6,37,27 as follows.

Step 36 is a table lookup of the gear ratio set value, which is the criterion for starting the gear shift, by the subroutine of FIG. 4. First, in steps 41 and 42, the shift solenoid which is known from the kind of the gear shift (see step 31). A,
Set the pre-shift state and post-shift state of B. Next, in steps 43 and 44, table data for each type of shift (table data for 1 → 2 shift in FIG. 7 and table data for 1 → 4 shift via third speed in FIG. 8 are illustrated. ), The gear ratio set values g ₁ and g ₂ for the shift solenoid A and the gear ratio set values g ₃ and g ₄ for the shift solenoid B are looked up from the throttle opening TH and the idle signal I _d .

These gear ratio setting values are set to 0
Corresponds to the reference value of the gear ratio for determining whether to switch N, OFF (shift should be started). Two kinds of gear ratio setting values g ₁ , g ₂ and g ₃ , g ₄ are set for the shift solenoids A and B, respectively, as shown in FIG. The shift solenoid, for example
This is because it is necessary to switch from ON to OFF to ON.
Therefore, when the jump shift is not performed, the gear ratio setting values g ₁ and g ₂ are made the same, and g ₃ and g ₄ are made the same, as shown in FIG. 7, for example.

In step 37 in FIG. 3, depending on what the gear ratio g (see step 23) is with respect to the above gear ratio setting value, the subroutine in FIG. ON, OFF) is determined as follows.

First, in step 51, it is determined whether it is an upshift or a downshift. If it is an upshift, it is checked in steps 52 and 53 whether or not the gear ratio g is less than or equal to the set values g ₁ and g ₂ . When g> g _1, the pre-shift state of shift solenoid A is set in step 54 (see step 41), and when g ≦ g ₁ and g> g ₂ , the shift solenoid A is in the opposite state to the pre-shift state. Then, the ON / OFF switching is set so that g ≦ g ₂ is reached and the post-shift state of the shift solenoid A (see step 41) is set.

After that, in steps 57 to 61, the gear ratio g and set value are the same as above.
By comparing with g ₃ and g ₄ , the shift solenoid B is set to the pre-shift state, the reverse state, or the post-shift state.

Also, when it is determined that a downshift is performed in step 51, similarly to the above, steps 62 to 71 set the pre-shift state, the reverse state, or the post-shift state of the shift solenoids A and B.

After determining the states of shift solenoids A and B in this way,
In step 27 in FIG. 3, a solenoid drive signal is output to the shift solenoids A and B so as to obtain the set state.

As a result, the automatic transmission automatically selects the first speed, the second speed, the third speed, or the fourth speed according to the shift pattern shown by the solid line in FIG. When the operating state is changed such that the vehicle shifts through a shift line omitted), a corresponding automatic shift can be performed. And during this shift,
Since the gear shift is started when the gear ratio g reaches the set values g ₁ , g ₂ , g ₃ , g ₄ , the gear ratio after the gear shift is changed by the gear input speed with respect to the gear output speed (vehicle speed). This is executed at the time of synchronization with a value that takes into consideration, and it is possible to minimize shift shock.

When it is determined in step 35 in FIG. 3 that T ≧ T _S , that is, when the set time T _S after shift determination has elapsed, the shift control of the present invention is executed in step 38 by the subroutine in FIG. That is, in step 81, 82, etc., the type of shift (step 31
(Refer to FIG. 3) is performed, and shift control is performed such that the 1 → 3 shift is controlled next for each shift type.

That is, in step 83, it is checked whether or not the shift solenoids A and B are already in the third speed state after the shift, and if so, the shift control is not necessary and the control is returned to the main routine of FIG. If the shift solenoids A and B are not in the third speed state yet, step 84
Then, it is checked whether or not the gear ratio g is equal to or lower than the gear ratio of the second speed which is an intermediate shift stage of 1 → 3 shift. If so, it is a gear ratio that can be applied to the second speed, so in step 85, the second speed state of the shift solenoids A and B is determined, and in the next step 86, 2 → 3.
In order to prohibit the upshift gear shift, the 2 → 3 upshift line is changed from the solid line position in FIG. 9 to the dotted line position, and the shift line change flag FL is set in the next step 87 to indicate this change.
Set G to 1 and return to the main routine of FIG.
At this time, in step 27 in FIG. 3, the shift solenoids A and B are switched on and off according to the determination of step 85, and the forced shift to the second speed is executed.

If it is determined in step 84 that the gear ratio g is greater than the second gear ratio, it is not a gear ratio that can be applied to the second gear, so the first state of the shift solenoids A and B is determined in step 88. Then, in order to prohibit the upshift from the first speed, the 1 → 2 upshift line and the 2 → 3 upshift line are respectively changed from the solid line position in FIG. 9 to the dotted line position in step 89, and this is changed in step 90. Set FLG = 1 as shown.
Then, when returning to the main routine of FIG. 3, in step 27,
ON / OFF of shift solenoids A and B as determined in step 88
The control is performed to hold the first speed.

Due to the above, if the corresponding upshift is not executed even after the set time T _S has elapsed after the foot release upshift is determined, the forced upshift is performed to the lower speed gear closest to the gear ratio, and then Since the upshift shift is prohibited, the engine will not be over-rotated due to the prohibition of the upshift shift at the time of re-depressing, and the driving feeling can be prevented from deteriorating.

(Effects of the Invention) As described above, the shift control device of the present invention, as described above, forcibly shifts to the shift stage on the low speed side closest to the gear ratio when the set time elapses after the foot release upshift determination, and shifts the upshift shift thereafter. Because it was banned to prevent shocks,
Even if the upshift determination is an interlaced shift determination, the forced shift does not cause over-rotation of the power source or the like due to prohibition of upshifting at all, and the driving feeling deteriorates. Can be prevented.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a conceptual diagram of a shift control device of the present invention, FIG. 2 is a control system diagram of a vehicle power train showing an embodiment of the present invention device, and FIGS. 3 to 6 are 7 is a flowchart showing a control program of a shift control computer in the same example, FIGS. 7 (a) and 7 (b) are characteristic diagrams of 1 → 2 shift gear ratio set values, and FIGS. 8 (a) and 8 (b), respectively. Are characteristic diagrams of the gear ratio set values for 1 to 4 shifts, respectively, FIG. 9 is a shift pattern diagram of an automatic transmission, FIG. 10 is a shift operation waveform diagram of a conventional device, and FIG. 11 is a proposal previously made by the applicant of the present application. FIG. 6 is a waveform chart of a gear shift operation performed by the device. 1 ... Electronically controlled fuel injection engine 2 ... Automatic transmission 3 ... Differential gear 4 ... Drive wheel 5 ... Engine control computer 6 ... Engine rotation sensor 7 ... Vehicle speed sensor, 8 ... Throttle sensor 9 ... Intake air amount sensor 10 ... Torque converter 11 ... Speed change gear mechanism 14 ... Speed change control computer 15 ... Control valves A, B ... Speed change control shift solenoid 16 ... Line pressure control duty solenoid 17 ... Input rotation sensor 18 ... Output rotation sensor 19 ... Idle switch

Claims (1)

[Claims] Claim: What is claimed is: 1. Various friction elements of a speed change gear mechanism are selectively operated to determine a speed change step, and the speed of the speed change gear mechanism is changed to another speed step by changing the operating friction element. An automatic transmission that performs a corresponding upshift when the gear ratio, which is represented by the ratio between the input and output speeds of the transmission gear mechanism, reaches a set value after an upshift determination due to the shift to the off state. A time-measuring means for measuring an elapsed time after the upshift determination, and a forced speed-changing means for putting a speed change gear mechanism into a speed-shift gear closest to the gear ratio when the elapsed time reaches a set time, A shift control device for an automatic transmission, comprising: a shift inhibiting means for inhibiting an upshift shift after the forced shift.