JPH089307B2 - Control method of automatic transmission for vehicle - Google Patents

Description

TECHNICAL FIELD The present invention relates to an improvement in a control method for an automatic transmission for a vehicle.

2. Description of the Related Art When automatically switching a plurality of gears of a stepped transmission, the output reduction process of reducing the output of the engine and the automatic clutch release to temporarily suspend the power transmission of the engine are described. A vehicular automatic transmission of a type including a power transmission interruption step of switching a gear stage of a stepped transmission, and a re-transmission step of engaging the automatic clutch and again transmitting power of the engine after the gear stage is switched. The control method of is considered. For example, this is a control method executed at the time of shifting in an automatic transmission of the type described in JP-A-59-81230.

Problems to be Solved by the Invention However, in such a conventional control method for an automatic transmission, normally, the throttle valve is controlled to be in a fully closed state prior to switching the gear stage of the stepped transmission, and the control is not performed again. In the transmission process, the throttle valve opening is increased at a constant increasing speed, so during automatic shift of the synchronous mesh type stepped transmission, among the power reduction process, the power transmission interruption process, and the re-transmission process, particularly the power transmission is performed. A shift shock was generated due to the interruption process, and the drivability was impaired. That is,
When the gear stage of the stepped transmission is changed, the engine speed in the power transmission interruption step is different from the input shaft speed of the stepped transmission after the new gear stage is established. An engagement shock occurs due to the rotation difference between the input side and the output side of the automatic clutch.

Means for Solving the Problems The present invention has been made in the background of the above circumstances, and the gist thereof is to automatically switch a plurality of gear stages of a synchronous mesh type stepped transmission, An output reduction step of reducing the output of the engine; a power transmission interruption step of switching the gear stage of the stepped transmission while temporarily discontinuing the power transmission of the engine by releasing the automatic clutch; And a re-transmission step of re-engaging the automatic clutch to re-transmit the power of the engine after switching the gears.
An input shaft rotation speed calculating step of calculating an input shaft rotation speed of the stepped transmission after the gear shift of the stepped transmission from a gear ratio of the stepped transmission and a vehicle speed; output torque of the engine and a throttle valve A power transmission interruption step for rotating the engine when the output torque is substantially zero at the input shaft rotation speed calculated in the input rotation speed calculation step from the previously determined relationship between the opening degree and the engine rotation speed. Target throttle valve opening degree determining step including a calculation step of calculating a target throttle valve opening degree for the power transmission, and (b) the actual throttle valve opening degree in the power transmission interruption step is the target throttle valve opening degree for the power transmission interruption step. And a throttle control step for controlling so that

In this way, in the target throttle valve opening degree determining process, the input shaft rotation speed is calculated from the relationship between the engine output torque, the throttle valve opening degree, and the engine rotation speed, which is obtained in advance. The target throttle valve opening degree for the power transmission interruption process for rotating the engine when the output torque is substantially zero at the input shaft rotation speed calculated in the process is calculated in the calculation process. Then, in the throttle control step, the actual throttle valve opening is controlled so as to become the target throttle valve opening for the power transmission interruption step. That is, according to the present invention, in the automatic transmission of the synchronous mesh type stepped transmission, in the power transmission interruption step, the output torque of the engine operating at the same rotation as the input shaft rotation speed of the automatic transmission becomes substantially zero. As described above, the throttle valve opening is controlled, and the automatic clutch is re-engaged in the subsequent re-transmission step while the output torque of the engine is substantially zero. Therefore, the engagement shock that occurs when the automatic clutch is re-engaged is preferably eliminated, and the drivability is improved.

Here, the target throttle valve opening determination step preferably includes a step of obtaining an actual rotation speed of the engine,
From the predetermined relationship among the output torque of the engine, the throttle valve opening, and the engine rotation speed, based on the predetermined output torque value and the actual engine rotation speed in the output reduction step, the engine And a calculation step of calculating a target throttle valve opening for an output reduction step for setting the output torque of the output torque value to the predetermined output torque value. The throttle valve opening is controlled so that the throttle valve opening becomes the target throttle valve opening for the output reduction process. The predetermined output torque value is usually zero or a small value close to zero. By doing so, the engine output torque does not become a negative torque in the output reduction step, so that the occurrence of deceleration shock due to the negative torque of the engine is eliminated.

Further, the step of determining the target throttle valve opening is preferably a step of obtaining an actual rotation speed of the engine,
Determining the actual transmission torque of the automatic clutch,
The output torque of the engine is made substantially the same value as the transmission torque based on the actual rotation speed of the engine from the previously determined relationship among the output torque of the engine, the throttle valve opening, and the engine rotation speed. And a calculation step of calculating a target throttle valve opening degree for the re-transfer step for controlling the re-transfer step target throttle valve for the re-transfer step. The throttle valve is controlled so that the opening is maintained. In this way, the throttle valve opening can be increased so that the output torque of the engine in the re-transmission process becomes equal to the transmission torque of the automatic clutch, so that the engine rotation is blown by the excessive increase of the throttle valve opening. This eliminates the occurrence of a connection shock caused by the rising of the clutch and the excessive increase in the transmission torque of the automatic clutch.

Examples Hereinafter, one application example of the present invention will be described in detail with reference to the drawings.

In FIG. 2, the power of the engine 10 of the vehicle is transmitted to the drive wheels via the magnetic powder type electromagnetic clutch 12, the stepped transmission 14, and a differential gear device (not shown).

The magnetic powder type electromagnetic clutch 12 functions as an automatic clutch of this application example, and includes a crankshaft 15 and a stepped transmission.
It is inserted between the input shaft 14 and the input shaft 46, and as shown in FIG. 3, engagement control is performed by the exciting current supplied from the control device 16 to transmit a torque having a magnitude corresponding to the exciting current. To do. Input shaft 46 of the crankshaft 15 and the stepped transmission 14
Corresponds to the input shaft and the output shaft of the magnetic powder type electromagnetic clutch 12. The stepped transmission 14 is a well-known manual transmission, which is a five-step forward one-step reverse-gear synchronous mesh transmission.
For example, as shown in FIGS. 4 and 5, a shift rod 18 having a shift fork (not shown) for shifting to the first speed gear and the second speed gear, the third speed gear and the fourth speed gear are attached. A shift rod 20 having a shift fork 19 for shifting to a high speed gear stage and a shift rod 22 having a not shown shift fork for shifting to a fifth speed gear stage and a reverse gear stage
And a shift device for selectively driving the shift rods 18, 20, 22 from the neutral position to the shift position. The shift device is a shift select lever.
A three-position hydraulic cylinder for shifting, which drives 24 in a rotating direction to axially drive any one of the shift rods 18, 20, 22.
26 and the shift select lever 24 are rotatably supported, and the lower end portion of the shift select lever 24 is moved to the above-mentioned shift rod by positioning the shift select lever 24 at three positions in the rotation axis direction.
A switching three-position hydraulic cylinder 28 that engages with any one of 18, 20, and 22 is provided. 3-position hydraulic cylinder for shifting 26
Is controlled to a 3-position by a combination of operations of a pair of solenoid valves 30 and 32, and a switching 3-position hydraulic cylinder 28 is also controlled to a 3-position by a combination of operations of a pair of solenoid valves 34 and 36. It is supposed to be done. That is, by the combination of the operations of the solenoid valves 30, 32, 34 and 36, the operating hydraulic pressure supplied from the hydraulic pump 37 to the hydraulic circuit 38 is selectively applied to the shift 3-position hydraulic cylinder 26 and the switching 3-position hydraulic cylinder 28. When the solenoid valves 34 and 36 are both turned on, the switching 3-position hydraulic cylinder 28 moves the shift select lever 24 to the third position.
The shift rod 20 for switching between the high speed gear stage and the fourth speed gear stage is engaged, but when the solenoid valve 34 is on and the solenoid valve 36 is off, the switching three-position hydraulic cylinder 28 shifts the shift select lever 24. Is engaged with the shift rod 18 for switching between the first speed gear stage and the second speed gear stage, and conversely, when the solenoid valve 34 is off and the solenoid valve 36 is on, the switching three-position hydraulic cylinder 28 becomes The shift select lever 24 is engaged with the shift rod 22 for switching between the fifth speed gear and the reverse speed gear. When the solenoid valves 30 and 32 are both on, the shift three-position hydraulic cylinder 26 is positioned in the neutral state, but when the solenoid valve 30 is on and the solenoid valve 32 is off, the shift three-position hydraulic cylinder is on. The cylinder 26 moves any one of the shift rods toward the first speed, the third speed, and the fifth speed, and conversely, when the solenoid valve 30 is off and the solenoid valve 32 is on, the shift three-position hydraulic cylinder 26 Moves one of the shift rods to the second speed, the fourth speed, and the reverse side. FIG. 6 shows the relationship between the locus of movement of the upper end portion of the shift select lever 24 and the gear stages established thereby.

The vehicle is provided with various sensors for detecting driving parameters, and signals from these sensors are supplied to the control device 16. In other words, the accelerator sensor 42 provided on the accelerator pedal 40 outputs the voltage signal v _acc representing the accelerator operation amount to the control device 16. Engine speed sensor provided in the engine 10
A signal t _e representing the engine rotation period is sent from the controller 16 from 44.
Is output to. Input shaft 46 and output shaft 48 of the stepped transmission 14
From the input shaft rotation sensor 50 and the output shaft rotation sensor 52 provided in the vicinity of the signal t _in
And a signal t _out representing the rotation cycle of the output shaft 48 is a control device.
Output to 16. Further, signals N _sw 4 to N _sw 1 are output to the control device 16 from the shift position detection switches 54, 56, 58, 60 provided in the stepped transmission 14. The operating position of the shift 3-position hydraulic cylinder 26 is detected by the combination of signals from the pair of shift position detection switches 54 and 56, and the switching 3-position hydraulic cylinder is combined by the signal from the pair of shift position detection switches 58 and 60. 28 operating positions are to be detected. These shift position detection switches
54, 56, 58, and 60 are Japanese Patent Application No. 61-
It is similar to that described in 41977.

The control device 16 includes a CPU 66, a ROM 68, a RAM 70, an input interface 72, a clutch drive circuit 74, and a throttle drive circuit 7.
6, a so-called microcomputer provided with a solenoid valve drive circuit 78 and the like, processing the input signal according to a program stored in advance in the ROM 68 while utilizing the storage function of the RAM 70,
A drive signal for driving the solenoid valves 30, 32, 34, 36 is output from the solenoid valve drive circuit 78, and an exciting current for controlling the electromagnetic clutch 12 is output from the clutch drive circuit 74. From the throttle drive circuit 76, the engine 10
A drive signal is output to a throttle actuator 82 that drives a throttle valve 80 provided in the intake pipe. Further, a throttle sensor 84 for detecting the opening degree of the throttle valve 80 is provided, and the output signal v _th of the throttle sensor 84 is supplied to the input interface 72.

FIG. 7 shows an example of the output terminal configuration of the solenoid valve drive circuit 78 consisting of 4 bits of 0th bit to 3rd bit. 0
The number 1 bit, the number 1 bit, the number 2 bit, and the number 3 bit correspond to the solenoid valves 30, 32, 34, and 36, respectively. Similarly, FIG. 8 shows a partial configuration example of the input terminal of the input interface 72 consisting of 4 bits of 0th bit to 3rd bit. 0th bit, 1st bit, 2nd bit, 3rd bit are shift position detection switches 54, 56, 58,
They correspond to 60 respectively.

The operation of this application example will be described below with reference to the flowchart of FIG.

First, in step S1, the input signal from each sensor
t _e , t _in , t _out , v _acc , V _th , N _sw 1 to N _sw 4 are read. Next, in step S2, the actual engine rotation speed N _e , the input shaft rotation speed N _in , and the output shaft rotation speed are calculated from the above signals according to the following equations (1), (2), (4), (5), and (6). N _out , vehicle speed SPD, accelerator operation amount _Acc , and throttle valve opening θ are calculated.

N _e rpm = (1 / t _e ) × 60 sec ・ ・ ・ (1) N _in ＝ (1 / t _in ) × 60 sec ・ ・ ・ (2) N _out ＝ (1 / t _out ) × 60 sec ・ ・ ・ ( 3) SPDkm / h ＝ N _out・ γ _dif・ 2πr ・ 60 _min・ 1/1000 ・ ・ ・
(4) where r is the wheel radius and the gear ratio of the γ _dif differential gear device.

A _cc = (v _acc −v _close ) / (v _max −v _close ) ・ 10 ・ ・ ・
(5) However, v _close and v _max are output signals from the accelerator sensor 42 when the accelerator pedal 40 is not operated and when it is fully operated.

θ% = (v _th −v ^close ) / (v ^max −v ^close ) · 10 ・ ・ ・
(6) However, v ^close and v ^max are output signals from the throttle sensor 84 when the throttle valve 80 is fully closed and fully opened.

In the following step S3, the gear stage determination routine shown in FIG. 10 is executed, and the current gear stage is determined based on the signals N _sw 4 to N _sw 1 from the shift position detection switches 54, 56, 58, 60. Is detected. Since the signals N _sw 4 to N _sw 1 are supplied to the input terminals arranged as shown in FIG. 8, they are judged by the binary number B represented by the bit arrangement of the terminals. That is, when neither of the signals N _sw 4 to N _sw 1 is supplied, the binary number B becomes zero, so that the stepped transmission 14 is judged to be in the neutral state, and the signal N _sw 2
And N _sw 4 are supplied, the binary number B is 5, so it is determined to be the first gear, and when the signals N _sw 2 and N _sw 3 are supplied, the binary number B is 6. Therefore, if it is determined that the second gear is selected and only the signal N _sw 4 is supplied, the binary number B
Is determined to be the third gear, and when only the signal N _sw 3 is supplied, the binary number is 2, so it is determined to be the fourth gear, and the signals N _sw 1 and N _sw 4 are determined. Is supplied, the binary number B becomes 9, so it is determined to be the fifth speed gear stage. When the signals N _sw 1 and N _sw 3 are supplied, the binary number B becomes 10 and therefore the reverse gear stage. And the value indicating the current gear stage is stored in the register γ.

In the following step S4, it is determined whether or not the content of the shift sequence flag F _chg indicating that the shift operation is being executed is "0". If it is not "0", steps S8 and below, which will be described later, are executed in order to preferentially execute the shift control.
If it is "0", it means that the gear shifting operation has been completed.
In S5, the target gear stage determination routine shown in FIG. 11 is executed to determine the target gear stage for the next shift. That is, in steps SM1 to SM12, based on the numerical value indicating the actual gear stage in the register γ, the shift diagram corresponding to the actual gear stage is selected from the plurality of types of shift diagrams stored in the ROM 68 in advance. In addition to being selected, in step SM13, the upshift shift point vehicle speed SPD _up and the downshift shift point vehicle speed SPD _down are calculated by interpolation calculation based on the actual throttle valve opening from the shift diagram. Then, in step SM14, the actual vehicle speed
When SPD becomes equal to or higher than the shift point vehicle speed SPD _up, the content of the register γ ^* that stores the numerical value indicating the target gear stage is set to γ + 1 in step SM15, but the actual vehicle speed SPD is the downshift gear point in step SM16 Vehicle speed SPD
_{When the value} becomes _down or less, the content of the register γ ^* is set to γ-1 in step SM17. That is, the content of the register γ ^* is set to be a gear step one step higher than the current gear step or a gear step one step lower than the current gear step. 12 (a), (b) and (c) show steps SM2, SM4 and SM10 described above.
3 are examples of shift diagrams selected in FIG. In the figure, the solid line is for obtaining the shift point vehicle speed during upshifting, and the broken line is for obtaining the shift point vehicle speed during downshifting. Further, in step SM13, for example, if the shift diagram is as shown in FIG. 13, calculation of the shift point vehicle speed from the data map forming the diagram is performed by calculating the actual accelerator operation amount A _cc and the map. Sequentially comparing with the X-axis data, when _Acc <X-axis data is set to X _2, and the previous X-axis data when _Acc <X-axis data is set to X ₁ , the following formula (7) is obtained. Therefore done.

Returning to FIG. 9, when the target gear stage is determined as described above, in step S6, the target gear stage indicated by the contents of the register γ ^{* and} the actual gear stage indicated by the contents of the register γ match. It is determined whether or not to do it. If they match, the gear shifting operation is not required, so steps S10 and below are executed. However, if they do not match, the gear shifting operation is necessary, and therefore steps S7 and below are executed. That is, by executing step S7, the content of the shift sequence flag F _chg is first set to "1" before the shift operation, and then in step S8, the shift operation routine shown in FIG. 1 is executed. Register the gear stage of the stepped transmission 14 ^*
A series of gear shift operations for switching to the target gear stage shown in the contents of are performed.

In FIG. 1, first, in step SH1, the content of the shift sequence flag F _chg is determined. When the content of the shift sequence flag F _chg is "1", a series of steps SH2 to SH8 for starting the shutoff operation are executed. The fact that the content of the shift sequence flag F _chg is "1" indicates that the engine output reduction process is being executed. In step SH2, it is obtained in advance and ROM
From the engine characteristics stored in 68, the actual output torque T _e of the engine 10 is calculated based on the actual engine speed N _e and the actual throttle valve opening θ. The engine characteristic is, for example, the relationship (engine torque map) between the output torque T _e , the engine rotation speed N _e, and the throttle valve opening θ as shown in FIG. The calculation of the output torque T _e is executed as follows. First, let the engine speed N _e be X
The axis coordinates and the throttle valve opening θ are converted into Y axis coordinates. For this conversion, for example, with respect to the engine rotation speed N _e , "0" is set as an initial value in the coordinate X, and in this state, the engine rotation speed N _e > X-axis data is determined, and when it is established, the coordinate X is set to 1 Is added and sequentially compared with the next X-axis data. When the engine rotation speed N _e <X-axis data, a pair of X-axis data sandwiching the engine rotation speed N _e is held. The pair of X-axis data thus obtained is X _{1 in} FIG.
And X ₂ . As shown by Y ₁ and Y _{2 in} FIG. 15, a pair of Y-axis data of the throttle valve opening θ can be similarly obtained. Then extracted output torque data b specified by the output torque data a and the coordinates Y ₁ and X ₂ of the intersections X is identified by the intersection of coordinate Y ₁ and X ₁ from an engine characteristic diagram of FIG. 14, coordinate Y _The engine output torque e shown at the intersection of ₁ and the engine rotation speed N _e is calculated based on the following expression (8), for example.

Similarly, output torque data c specified by the intersection of coordinates Y ₂ and X ₁ and output torque data d specified by the intersection X of coordinates Y ₂ and X ₂ are extracted from the engine characteristic diagram of FIG. _The engine output torque f shown at the intersection of ₂ and the engine rotation speed N _e is calculated based on the following expression (9), for example.

Then, the output torque T _e corresponding to the actual throttle valve opening θ and the engine rotation speed N _e is calculated from e and f obtained as described above according to the following equation (10).

In this way, when the actual output torque T _e of the engine 10 is obtained in step SH2, the absolute value | T _e | of the output torque of the engine 10 in step SH3 is the preset target output torque T _off during power shutoff T _off. Is greater than or equal to. If it is not large, the purpose of the output reduction process has been achieved, so the following steps SH9 and below that constitute the power transmission interruption process are executed, but if it is large, from the engine torque map shown in FIG. 14 in step SH4. Actual engine speed N _e and the target output torque T _off
The target throttle valve opening θ _off ^* is determined based on This target throttle valve opening θ _off ^* is
_Is a relatively small value for making the output torque T _e of the above T _off, and as shown in FIG. 16, first, the X coordinate of the engine rotation speed N _e is obtained by the same conversion method as in the case of step SH2. , The output torque T ₀ specified by the intersection of the Y-axis coordinate Y ₀ corresponding to the throttle valve opening θ and the engine rotation speed N _e
Is calculated by the same method as the equation (10) and is calculated according to the following equations (11), (12) and (13). That is, the engine output torque T _{0 at} the coordinate Y ₀ and the target output torque T
_Off is compared, and when T ₀ <T _off , the next Y-axis, in other words, the engine output torque T ₁ indicated by the intersection of the coordinate Y ₁ and the engine rotation speed N _e is calculated, and T ₁ and T are again calculated. Compare with _off . Thus continue to sequentially compare, T _n ≧ T _off when a coordinate Y _(n-1) of the engine output torque T _(n-1) and T _n, Y _n and
Throttle valve opening θ _n and θ _(n-1) corresponding to Y _{(n -1)}
And the target output torque T _off , the target throttle valve opening θ
_It calculates _off ^* .

In step SH5, the actual throttle valve opening θ is calculated as above by the target throttle valve opening θ _off ^*
The control amount V _th for the throttle actuator 82 is determined according to the following control equation (14) in order to match

In step SH6, the current control amount V _cl for the electromagnetic clutch 12 is updated as the previous control amount V _{cl (n-1)} , and in step SH7 each shift solenoid valve 3
The content of the control amount V _shift for 0, 32, 34, 36 is zero, that is, the drive signal is not output to any solenoid valve. Then, in step SH8, the content of the shift sequence flag F _chg is set to "1". While the above series of steps are repeated, the control amount V _th for the throttle actuator 82 is changed so that the throttle valve opening θ becomes equal to the target throttle valve opening θ _off ^* . In such a state, the absolute value | T _e | of the output torque of the engine 10 becomes equal to the target engine torque T in step SH3.
_Since it is determined to be _off or less, the output reduction step is ended, and the power transmission interruption step of step SH9 and thereafter for switching the gear stage while interrupting power transmission is started.

In step SH9, it is judged whether or not the actual gear stage stored in the register γ and the target gear stage stored in the register γ ^* match. If they match, the gear stage switching operation is completed. Since it is in a state, the steps described below
SH16 and subsequent steps are executed, but if they do not match, the control amount V _cl is made zero in step SH10 in order to release the electromagnetic clutch 12 and avoid a gear change failure due to engine inertial force or the like. Then, in step SH11, the engine rotation speed N _e ^* when the target gear stage to be shifted is established is calculated from the following equation (15) based on the actual output shaft rotation speed N _out.
And calculated based on the gear ratio γ _ratio ^* of the target gear stage. The gear ratio γ _ratio ^* of this target gear is, for example, the first
It is shown in Fig. 7.

N _e ^* = γ _ratio ^* × N _out (15) In the subsequent step SH12, the engine speed N _e ^* when the target gear stage is established and the actual engine speed N _e are made equal to each other. That is, the target throttle valve opening θ _ne ^* for power transmission interruption for making the output torque of the engine 10 substantially zero is calculated. Then, in step SH13, the control amount V _th for the throttle actuator 82 is changed.
Is the value θ _ne ^* for matching the target throttle valve opening θ _ne ^* with the actual throttle valve opening θ. Next, the gear stage switching routine of step SH14 is executed.

The gear stage switching routine is executed, for example, as shown in FIG. First, in step SG1, the data indicating the target gear stage stored in the register γ ^* is processed by using the signal processing routine shown in FIG.
It is converted into a numerical value that can be easily handled as a drive signal and a numerical value that can be output with the bit array as it is when it is a binary number. That is, in order to convert into the data of the same arrangement as the input terminal of the input interface 72 shown in FIG.
The data indicating the target gear is the shift-side data γ ^* _sh for operating the shift hydraulic cylinder 28 and the select-side data γ ^* _sl for operating the switching hydraulic cylinder 26 in accordance with a predetermined fixed rule. Is converted to. For example, if the target gear is the first gear, the shift side data γ ^* _sh is “1” and the select side data γ ^* _sl is “4”, and if the target gear is the second gear. The shift side data γ ^* _sh is “2” and the select side data γ ^* _sl
Is set to “4”, and if the target gear is the third gear, the shift side data γ ^* _sh is “1” and the select side data γ ^*.
_{If sl} is set to "0" and the target gear is the fourth gear, shift side data γ ^* _sh is "2" and select side data γ.
^{* If} _sl is "0" and the target gear is the fifth gear, the shift side data γ ^* _sh is "1" and the select side data γ ^* _sl is "8", and the target gear is If it is the sixth speed (reverse) gear, the shift side data γ ^* _sh is “2” and the select side data γ ^* _sl is “8”.

Returning to FIG. 18, in the subsequent step SG2, the contents of the register γ are converted into shift side data γ _sh and select side data γ _sl by a processing routine not shown in the same manner as above. These shift side data γ _sh and select side data γ _sl are the lower 2 bits of the signal sequence of the signals N _sw 4 to N _sw 1 supplied from the shift position detection switches 54, 56, 58, 60 to the input interface 72. And the upper 2 bits (including the lower 2 bits of “0” as a numerical value).

Step SG3 based on actual gear stage and the select side data γ ^* _sl based on the target gear stage in the select data γ _sl
It is determined whether and match, and step SG
4, whether the shifting-side data gamma _sh based on actual gear shift side data gamma ^* _sh based on the target gear position matches are determined. When the determinations at steps SG3 and SG4 are both affirmative, there is no need to switch the gear, so step SG5 is executed and the content of the control amount V _shift is made zero. However, if the determination in step SG3 is positive but the determination in step SG4 is negative, step SG6 is executed and the content of the control amount V _shift is set to the shift side data γ ^* _sh based on the target gear stage. As a result, the shift three-position hydraulic cylinder 26 is driven in step S9, which will be described later, and the target gear stage is established. If the determination in step SG3 is negative, it is necessary to use a shift rod different from the one currently engaged with the shift select lever 24.
In 7, whether or not the shift-side data γ _sh based on the actual gear stage is zero, that is, the 3-position hydraulic cylinder for shifting.
It is determined whether 26 is in the neutral position. This step
If the determination in SG7 is affirmative, in order to operate the switching three-position hydraulic cylinder 28 to the position for selecting the shift rod for operating the target gear, the content of the control amount V _shift is set to the target gear stage in step SG8. Based on the selected side data γ ^* _sl . However, if the determination in step SG7 is negative, the control amount V _shift is set to "3" in step SG9 in order to operate the shift three-position hydraulic cylinder 26 to the neutral position. This controlled variable
Since the content "3" of V _shift is binary "11", drive signals are output from the 0th bit and the 1st bit of the solenoid valve drive circuit 78 to the solenoid valves 30 and 32 in step S9. In this way, the three-position hydraulic cylinder for shifting 26
Is actuated to the neutral position, the shift rod is selected in steps SG8 and S9 of the next cycle, and steps SG6 and S9 of the next cycle are selected.
The target gear stage is established by.

When the execution of the gear stage switching routine in step SH14 of FIG. 1 is completed in this way, the content of the shift sequence flag F _chg is set to "2" in step SH15. When the gear steps are completed by executing the above steps,
Since it is determined in step SH9 that the target gear and the actual gear are the same, step SH16 for executing the re-transmission step of re-transmitting the power of the engine 10
The following is done:

In step SH16 throttle opening theta (%) whether smaller is determined than the accelerator operation amount A _cc (%). This step SH16 is to judge the end of the re-transmitting process. Since it is initially small, the control amount V _cl for the electromagnetic clutch 12 is increased by a predetermined constant increase value ΔV _cl (= ΔT _cl ) in step SH17. In the following step SH18, for example, the control amount V for the electromagnetic clutch 12 is calculated from the engine torque map shown in FIG.
_{Based on cl} and the actual engine speed N _e , the re-transmission target throttle valve opening θ _on ^* is calculated by the same method as in step SH4. That is, the electromagnetic clutch 12
The throttle valve opening degree θ for _obtaining an output torque similar to the transmission torque T _{cl of} is _calculated . And step SH
At 19, the control amount V _th for the throttle actuator 82 is set to a value θ _on ^* for matching the target throttle valve opening θ _on ^* and the actual throttle valve opening θ. In the following step SH20, each solenoid valve for shifting 3
The content of the control amount V _shift for 0, 32, 34, 36 is zero, that is, the drive signal is not output to any solenoid valve. Then, in step SH21, the content of the shift sequence flag F _chg is set to "3". In the process of repeating the above series of steps, the throttle actuator 82
The control amount V _th with respect to is gradually changed, and the throttle valve opening θ is made to follow the target throttle valve opening θ _on ^* in each case.

By a series of steps described above is repeated, when the throttle valve opening θ and the accelerator operation amount A _cc is determined to match in step SH16, step SH22
In, the content of the shift sequence flag F _chg is set to "0".

When the shift operation routine is completed as described above, the control values such as V _cl , V _th , and V _shift are output in step S9 in FIG. 9 to output the electromagnetic clutch 12, the throttle actuator 82, the electromagnetic valves 30, 32, 34, 36, etc. are driven. As a result, the gear stage of the stepped transmission 14 is switched to the target gear stage.

When it is determined in step S6 in FIG. 9 that the current gear speed and the target gear speed match, no gear shifting operation is necessary, so in step S10, the vehicle speed SPD is set to a predetermined low value ε. It is determined whether or not the following. The controlled variable V _cl for controlling the amount V _cl to the electromagnetic clutch 12 is to maximize the transmitted torque in step S11 it is necessary to keep the electromagnetic clutch 12 in the engaged state when the determination at step S10 is negative It is considered as ^max . However, if the determination in step S10 is positive, step S
In 12, the above control amount is calculated according to the control formula shown in the following formula (16).
V _cl is changed sequentially.

V _cl = (N _e −N _idl ) × K (16) However, K is a constant, and in step S13, the control amount V _th for the throttle actuator 82 is determined to correspond to the actual accelerator operation amount _Acc . After that, the control amount is output in step S9 described above.

As described above, according to this application example, in the output reduction process in the gear change of the stepped transmission 14, the engine
A target throttle valve opening θ _off ^* for output reduction for obtaining the output torque of 10 to a predetermined small target engine torque T _off is determined, and the actual throttle valve opening θ is set to the target throttle valve opening θ The output torque of the engine 10 does not become negative because it is controlled to _off ^* .
Therefore, even if the electromagnetic clutch 12 remains engaged when the throttle valve opening θ is reduced at the start of the automatic shift operation, the deceleration shock is prevented.

Further, in the power transmission interruption process in the gear shift of the stepped transmission 14, the power for making the engine rotation speed N _{e the} same rotation speed as the input shaft rotation speed N _in when the target gear speed is established. Target throttle valve opening for interruption θ
_{When ne} ^* is determined, the actual throttle valve opening θ
Is controlled to the target throttle valve opening θ _ne ^* ,
In the electromagnetic clutch 12, the output torque of the engine 10 at the time of re-engagement is made substantially zero, and the coupled shock of the electromagnetic clutch 12 caused by the rapid transmission of the output torque of the engine 10 is eliminated.

Further, in the re-engagement process at the switching of the gear stage of the stepped transmission 14, so that the output torque of the engine 10 with an increase in the transmission torque T _cl of the electromagnetic clutch 12 becomes equal to the transmission torque T _cl Since the target throttle valve opening θ _on ^* for reengagement is determined and the actual throttle valve opening θ is controlled to the target throttle valve opening θ _on ^* , the throttle valve opening θ and the electromagnetic clutch 12 are controlled. In the process of increasing the transmission torque _Tcl , the throttle valve opening θ
Does not become too large or too small with respect to the transmission torque of the electromagnetic clutch 12. Therefore, the occurrence of an engagement shock is preferably prevented by early engagement due to the engine 10 being blown up due to the excessive increase in the throttle valve opening and the excessive increase in the transmission torque of the electromagnetic clutch 12. It

As described above, one application example of the present invention has been described based on the drawings, but the present invention is also applied to other aspects.

For example, in the above-described application example, the target throttle valve opening degrees θ _off ^* , θ _ne ^* , which are respectively obtained in the output reduction process, the power interruption process, and the re-engagement process when the gear stage of the stepped transmission 14 is switched, The actual throttle valve opening θ is controlled so as to be θ _on ^* , but if the above-mentioned control is executed in the power interruption process, the operability is improved, which is a temporary effect.

Further, in step SH2 of the application example described above, the actual output torque of the engine 10 is calculated based on the actual engine rotation speed N _e and the throttle valve opening θ from the relationship obtained in advance. The output torque of the engine 10 may be detected by providing it.

Further, the common target engine torque T _off is used in steps SH3 and SH4 described above, but different values may be used.

Further, although the magnetic powder type electromagnetic clutch 12 is used in the above-mentioned application example, it may be an automatic clutch of another type such as a hydraulic clutch capable of engagement control.

The above is merely an application example of the present invention, and the present invention can be modified in various ways without departing from the spirit of the present invention.

[Brief description of drawings]

FIG. 1 is a diagram for explaining a gear shift operation routine which is a main part of the flowchart of FIG. FIG. 2 is a block diagram showing a shift control device of a stepped automatic transmission to which the present invention is applied. FIG. 3 is a diagram showing characteristics of the electromagnetic clutch shown in FIG. FIG. 4 and FIG. 5 are views showing a hydraulic drive system for switching the gear stage of the stepped transmission of FIG. 2, and are cross-sectional views of essential parts seen from cross sections perpendicular to each other. FIG. 6 is a diagram showing the relationship between the locus of the end of the shift select lever of FIGS. 4 and 5 and the shift position.
FIG. 7 and FIG. 8 are views for explaining the terminal configuration of the solenoid valve drive circuit of FIG. 2 and the partial terminal configuration of the input interface, respectively. FIG. 9 is a flow chart for explaining the operation of the shift control device of FIG. FIG. 10 and FIG. 11 are diagrams showing the routines executed in the flowchart of FIG. 9, respectively. Figure 12 (a),
(B), (c) is a figure which respectively shows the shift diagram previously stored in ROM of FIG. 2, (a) is a diagram selected in the 1st speed gear stage, (b) is a diagram The diagram selected in the 2nd gear stage, (c) is the diagram selected in the 5th gear stage. FIG. 13 is a diagram for explaining the calculation for obtaining the shift point vehicle speed in the flowchart of FIG. FIG. 14 is a diagram showing an example of engine output characteristics. First
FIG. 15 is a diagram illustrating a method for calculating the engine output torque. FIG. 16 is a diagram illustrating a method for calculating the target throttle valve opening. FIG. 17 is a chart showing a gear ratio of each gear of the stepped transmission. FIG. 18 is a diagram showing a routine executed in the flowchart of FIG. FIG. 19 is a diagram showing a routine executed in the flowchart of FIG. 10: Engine 12: Magnetic powder type electromagnetic clutch (automatic clutch)

Claims (3)

[Claims] Claim: What is claimed is: 1. When automatically switching between a plurality of gears of a synchronous mesh type stepped transmission, an output reduction step of reducing the output of the engine and an automatic clutch are released to temporarily suspend the power transmission of the engine. And a re-transmission step of re-transmitting the power of the engine by engaging the automatic clutch after shifting the gear stage A method for controlling an automatic transmission for a vehicle, comprising: calculating an input shaft rotation speed of the stepped transmission after a gear shift of the stepped transmission from a gear ratio of the stepped transmission and a vehicle speed; The input shaft rotation speed calculated in the input shaft rotation speed calculation step is calculated from the rotation speed calculation step and the previously determined relationship among the output torque of the engine, the throttle valve opening, and the engine rotation speed. And a target throttle valve opening degree determining step for calculating a target throttle valve opening degree for the power transmission interrupting step for rotating the engine when the output torque is substantially zero, and an actual step in the power transmission interrupting step. A throttle control step of controlling the throttle valve opening so as to be the target throttle valve opening for the power transmission interruption step, and a control method for an automatic transmission for a vehicle. 2. The target throttle valve opening determining step includes a step of obtaining an actual rotational speed of the engine and a predetermined relationship between the output torque of the engine, the throttle valve opening and the engine rotational speed. Therefore, based on the predetermined output torque value and the actual engine speed in the output reduction step, the output reduction step target throttle valve for setting the output torque of the engine to the predetermined output torque value And a calculation step of calculating an opening degree, wherein the control step is performed so that the actual throttle valve opening degree in the output reduction step becomes a target throttle valve opening degree for the output reduction step. The method for controlling an automatic transmission for a vehicle according to claim 1, wherein the method controls a vehicle. 3. The step of determining the target throttle valve opening, the step of obtaining an actual rotational speed of the engine, the step of obtaining an actual transmission torque of the automatic clutch, the output torque of the engine and the throttle valve opening. Based on a predetermined relationship with the engine rotation speed, the target throttle valve opening for the re-transmission process for making the output torque of the engine substantially the same as the transmission torque based on the actual rotation speed of the engine. And a calculation step of calculating the degree, wherein the control step controls the throttle valve so that the actual throttle valve opening in the re-transfer step becomes the target throttle valve opening for the re-transfer step. A method for controlling an automatic transmission for a vehicle according to claim 1, wherein