JPH0719325A - Speed change control device of automatic transmission for vehicle - Google Patents

Abstract

PURPOSE:To provide a speed change control device of an automatic transmission for a vehicle not causing sudden increase of driving force beyond expectation of a driver. CONSTITUTION:When an actual gear step organized in an automatic transmission 14 is detected by a gear step detection means 90, by a down shift gear step judgement means 92 and in accordance with the actual gear step, a gear step to shift down is judged so that gear ratio changing amplitude does not exceed a specified value, and a speed change command signal to take the gear step judged by this down shift gear step judgement means 92 is output to the automatic transmission 14. Consequently, at the time of down shift, as a gear step to shift down is judged so that the gear ratio changing amplitude by the down shiftdoes not exceed the specified value, sudden increase of driving force of a vehicle beyond expectation of a driver is prevented, and favourable operability can be acquired.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shift control device for an automatic transmission for a vehicle.

[0002]

2. Description of the Related Art In an automatic transmission for a vehicle having a plurality of forward gears, an engine load amount such as an actual accelerator pedal operation amount and a throttle valve opening and a vehicle speed can be calculated from a preset shift map. There is a shift control device of the type that determines the gear stage to shift based on. According to such a shift control device, there is an advantage that the automatic transmission can be automatically switched to the gear stage suitable for the running state of the vehicle. For example,
This is the shift control device for an automatic transmission for a vehicle, which is described in JP-A-4-25665.

[0003]

By the way, in the above-described conventional shift control device for an automatic transmission for a vehicle, when the driver depresses the accelerator pedal to a large extent, the shift diagram indicates the accelerator pedal operation amount. Thus, the speed reduction gear is determined and the speed is automatically downshifted to the speed reduction gear. However, in particular, in the case where a large operation of the accelerator pedal is performed, which is called kickdown, so that the throttle valve is fully opened, in addition to the fact that the engine output changes from a relatively small state to the maximum output, ,
Since the automatic transmission shifts down to the reduction gear stage, the driving force of the vehicle may suddenly increase beyond the driver's wishes, and good drivability may not be obtained. In particular, such inconvenience becomes more remarkable as the engine output of the vehicle increases.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a shift control device for an automatic transmission for a vehicle that does not cause a sudden increase in driving force that exceeds a driver's wish. To provide.

[0005]

In order to achieve the above object, the gist of the present invention is to provide an automatic transmission for a vehicle having a plurality of forward gears from an actual engine based on a preset shift diagram. A shift control device of the type for determining a gear stage to be shifted based on a load amount and a vehicle speed, (a) a gear stage detecting means for detecting an actual gear stage established in the automatic transmission, and b) Downshift gear stage determination means for determining the gear stage to be downshifted based on the actual gear stage detected by the gear stage detection means so that the range of change in gear ratio due to downshift does not exceed a predetermined value. And (c) shift control means for outputting to the automatic transmission a shift command signal for obtaining the gear speed determined by the downshift gear speed determination means.

[0006]

With this configuration, when the gear stage detecting means detects the actual gear stage established in the automatic transmission, the downshift gear stage determining means determines the actual gear stage based on the actual gear stage. The gear stage to be downshifted is determined so that the gear ratio change width due to the downshift does not exceed a predetermined value, and the shift command signal for obtaining the gear stage determined by the downshift gear stage determination means is the shift control means. Is output to the automatic transmission.

[0007]

Therefore, according to the present invention, when a downshift is performed, the gear stage to be downshifted is determined based on the actual gear stage so that the gear ratio change width due to the downshift does not exceed a predetermined value. Therefore, it is restricted that the driving force of the vehicle suddenly increases beyond the driver's wishes,
Good drivability is obtained.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a skeleton view showing an automatic transmission for a vehicle, the shift of which is controlled by a shift control device according to an embodiment of the present invention. In the figure, the output of the engine 10 is input to the automatic transmission 14 via the torque converter 12 and transmitted to the drive wheels via a differential gear unit and an axle (not shown).

The torque converter 12 is the engine 1
0 pump impeller 18 connected to crankshaft 16
A turbine runner 22 connected to the input shaft 20 of the automatic transmission 14, a lock-up clutch 24 that directly connects the pump impeller 18 and the turbine runner 22, and a one-way clutch 26 prevent rotation in one direction. And a stator 28 that is installed.

The automatic transmission 14 is provided with a first transmission 30 for switching between high and low gears, and a second transmission 32 for switching between reverse gear and four forward gears. The first transmission 30 includes an HL planetary gear device 34 including a sun gear So, a ring gear Ro, and a planetary gear Po that is rotatably supported by the carrier Ko and meshed with the sun gear So and the ring gear Ro, a sun gear So and a carrier. It includes a clutch Co and a one-way clutch Fo provided between Ko and a brake Bo provided between the sun gear So and the housing 41.

The second transmission 32 is a first planetary gear unit 36 comprising a sun gear S1, a ring gear R1, and a planet gear P1 rotatably supported by the carrier K1 and meshed with the sun gear S1 and the ring gear R1.
, Sun gear S2, ring gear R2, and carrier K
2 and a second planetary gear unit 38, which is rotatably supported by the sun gear S2 and a ring gear R2 and is meshed with the sun gear S2 and the ring gear R2; S3 and a third planetary gear set 40 including a planet gear P3 meshed with the ring gear R3.

The sun gear S1 and the sun gear S2 are integrally connected to each other, the ring gear R1, the carrier K2 and the carrier K3 are integrally connected, and the carrier K3 is connected to the output shaft 42. The ring gear R2 is integrally connected to the sun gear S3. A clutch C1 is provided between the ring gear R2 and the sun gear S3 and the intermediate shaft 44, and the sun gear S1 and the sun gear S are provided.
A clutch C2 is provided between the shaft 2 and the intermediate shaft 44. In addition, a band-type brake B1 for stopping the rotation of the sun gear S1 and the sun gear S2 is provided on the housing 41.
It is provided in. A one-way clutch F1 is provided between the sun gear S1 and the sun gear S2 and the housing 41.
And the brake B2 are provided in series. The one-way clutch F1 is configured to be engaged when the sun gear S1 and the sun gear S2 try to rotate in the opposite direction to the input shaft 20.

A brake B3 is provided between the carrier K1 and the housing 41, and a brake B4 and a one-way clutch F2 are provided in parallel between the ring gear R3 and the housing 41. This one-way clutch F
2 is configured to be engaged when the ring gear R3 tries to rotate in the reverse direction. The clutch Co, C
1, C2, brake Bo, B1, B2, B3, B4,
It is a hydraulic friction engagement device in which a friction material is engaged when hydraulic pressure is applied.

In the automatic transmission 14 configured as described above, for example, according to the operation table shown in FIG. 2, the reverse first gear and the forward five gears are switched. In FIG. 2, the ∘ mark indicates the operating state, and the X mark indicates the non-operating state.

As shown in FIG. 3, in the intake pipe of the engine 10 of the vehicle, a first throttle valve 52 and a throttle actuator 54 operated by an accelerator pedal 50.
And a second throttle valve 56 operated by. Further, an engine rotation speed sensor 58 that detects the rotation speed of the engine 10, an intake air amount sensor 60 that detects the intake air amount of the engine 10, an intake air temperature sensor 62 that detects the temperature of the intake air, the first throttle valve 5 described above.
The throttle sensor 64 for detecting the opening degree θth of 2 and the vehicle speed sensor 6 for detecting the vehicle speed V from the rotational speed of the output shaft 42 and the like.
6, a cooling water temperature sensor 68 for detecting the cooling water temperature of the engine 10, a brake switch 7 for detecting the operation of the brake
0, an operation position sensor 74 for detecting the operation position of the shift lever 72, etc. are provided.
Engine speed N _E , intake air amount Q, intake air temperature T
Signals representing Ha, the opening degree θth of the first throttle valve θ, the vehicle speed V, the engine cooling water temperature THw, the brake operating state BK, and the operation position Psh of the shift lever 72 are sent to the engine electronic control unit 76 and the shift electronic control unit 78. It is being supplied. Further, a signal indicating the turbine rotation speed N _T is supplied from the turbine rotation speed sensor 75 that detects the rotation speed of the turbine runner 22 to the electronic shift control device 78. Further, a signal indicating the kick down operation is supplied from the kick down switch 77 that detects that the accelerator pedal (not shown) is operated to the maximum operation position to the electronic shift control device 78.

The electronic control unit for engine 76 includes a CPU,
A so-called microcomputer including a RAM, a ROM, and an input / output interface, the CPU processes an input signal according to a program stored in the ROM in advance while utilizing the temporary storage function of the RAM, and executes various engine controls. For example, the fuel injection valve 80 is controlled to control the fuel injection amount, the igniter 82 is controlled to control the ignition timing, the bypass valve (not shown) is controlled to control the idle speed, and the throttle actuator is controlled to control the traction. The second throttle valve 56 is controlled by 54.

The electronic shift control device 78 is also a microcomputer similar to that described above, and the CPU uses the temporary storage function of the RAM while processing the input signal in accordance with the program stored in the ROM in advance, and the hydraulic control circuit 84. Each solenoid valve or linear solenoid valve is driven. For example,
The electronic shift control device 78 uses a linear solenoid valve SLT to generate an output pressure P _SLT having a magnitude corresponding to the opening degree θth of the first throttle valve 52, and a linear solenoid valve SLN to control the accumulator back pressure. To drive the linear solenoid valve SLU in order to control the slip amount of the lockup clutch 24. Further, the electronic shift control device 78 determines the gear position of the automatic transmission 14 and the engagement state of the lock-up clutch 24 based on the actual throttle valve opening θth and the vehicle speed V from the previously stored shift diagram. The solenoid valves S1, S2, S3 are driven so that the determined gear and engagement state are obtained, and the solenoid valve S4 is driven when engine braking is generated. The lock-up clutch 24 is released in the first gear stage and the second gear stage of the automatic transmission 14, but in the third gear stage and the fourth gear stage, the throttle valve opening θth and the vehicle speed V are.
Based on the above, the release, slip, or engagement region is determined, and if it is the slip region, the lockup clutch 2
4 is slipped, and if it is an engagement area, it is engaged. This slip control is for suppressing the rotational loss of the torque converter 12 as much as possible while absorbing the rotational fluctuation of the engine 10.

FIG. 4 shows the operating position of the shift lever 72. In the figure, the shift lever 72 is supported by a supporting device (not shown) that operably supports the shift lever 72 at eight operation positions by combining six operation positions in the front-rear direction of the vehicle and two operation positions in the left-right direction of the vehicle.
Is supported.

FIG. 5 is a functional block diagram for explaining the main part of the control function of the electronic shift control device 78. In the figure, when the actual gear stage established in the automatic transmission 14 is detected by the gear stage detection means 90, the downshift gear stage determination means 92 determines the actual gear stage based on the actual gear stage of the automatic transmission 14. , The gear stage to be downshifted is determined so that the gear ratio change range due to the downshift does not exceed a predetermined value, and the gear shift command signal for obtaining the gear stage determined by the gear stage determination means 92 is the gear shift control means. 9
4 to the automatic transmission 14.

The main part of the operation of the electronic shift control device 78 while the vehicle is traveling will be described below with reference to the flow chart shown in FIG.

In step SR1 of FIG. 6, the engine 10
After input signals such as the throttle valve opening θth corresponding to the load amount of the vehicle, the vehicle speed V, and the operation position Psh of the shift lever 72 are read, the shift lever 72 is moved to D in step SR2.
It is determined whether or not the range is operated. If the determination in step SR2 is negative, step SR
In step 3, the shift diagram corresponding to the actual operation position of the shift lever 72 is set from the shift diagram stored for each range, and in step SR4, the actual throttle valve opening is calculated from the set shift diagram. The shift gear is determined based on θth and the vehicle speed V, and in step SR5, a shift command signal is output from the shift electronic control unit 78 to the hydraulic control circuit 84 so that the determined gear is obtained.

When the determination at step SR2 is affirmative, at step SR6, the electronic shift control device 78 outputs whether or not the actual gear stage of the automatic transmission 14 is the fifth speed gear stage. The determination is made based on the gear shift command signal or the signal from a gear stage sensor (not shown) provided in the automatic transmission 14. If the determination in step SR6 is affirmative, after the shift diagram A for the fifth speed gear stage in the D range shown in FIG. 7 is selected in step SR7, the shift control in steps SR4 and SR5 is performed. To be executed. However, if the determination in step SR6 is negative, it is determined in step SR8 whether or not the actual gear stage of the automatic transmission 14 is the fourth speed gear stage, as in step SR6. This step SR8
If the result of the determination in step SR9 is affirmative, after the shift diagram B for the fourth gear in the D range shown in FIG. 8 is selected in step SR9, the steps SR4 and SR5 are performed.
The shift control of is executed. Then, the above step SR8
If the determination is negative, the shift control in steps SR4 and SR5 is executed after the normal shift map C shown in FIG. 9 is selected in step SR10.

As described above, according to this embodiment, when the actual gear stage established in the automatic transmission 14 is detected by steps SR6 and SR8 corresponding to the gear stage detecting means 90, the downshift gear is detected. By means of steps SR4, SR7, SR9 corresponding to the gear position determination means 92, the gear position to be downshifted is determined based on the actual gear position so that the gear ratio change width due to the downshift does not exceed a predetermined value. A shift command signal for obtaining the gear stage determined by the downshift gear stage determination means 92 is output to the automatic transmission 14 by step SR5 corresponding to the shift control means 94.

In the gear shift diagram shown in FIG. 7, the second gear range is modified so as to be smaller than the normal gear shift line shown by the broken line. For example, the accelerator can be used while the vehicle is running at the point G. When the pedal is kicked down, the shift down to the third gear is only performed. Therefore, according to this embodiment, at the time of downshifting, the gear stage to be downshifted is determined based on the actual gear stage so that the gear ratio change width due to the downshift does not exceed a predetermined value. The rapid increase in the driving force of the vehicle beyond the driver's desire is limited, and good drivability is obtained.

Incidentally, the automatic transmission 1 in the fifth speed gear stage
4 has a gear ratio i of 0.705, the gear ratio i of the automatic transmission 14 in the third gear is 1.418, and the gear ratio i of the automatic transmission 14 in the second gear is 2.208. Then, in the related art, the gear ratio i was changed from 0.705 to 2.208 by the kickdown operation, but according to the present embodiment, the change is limited to 0.705 to 1.418. .

FIG. 10 is a flow chart for explaining an essential part of the operation of the electronic shift control device 78 in another embodiment of the present invention. After the input signal is read in step SS1 in the figure, it is determined in step SS2 whether or not the operation position of the shift lever 72 is in the D range.
If the determination in step SS2 is negative, in step SS3, the shift diagram corresponding to the actual range is set as in step SR3, and then in step SS4, the same shift steps as in steps SR4 and SR5 are performed. The shift control is executed.

However, if the determination at step SS2 is affirmative, at step SS5, for example, as shown in FIG.
The normal shift diagram for the D range shown in is set, and in step SS6, the shift gear is determined from the shift diagram based on the actual throttle valve opening θth and the vehicle speed V. Next, in step SS7, it is determined whether or not the shift determination in step SS6 is a shift determination from the fifth gear to the second gear due to the kickdown operation. If the determination in step SS7 is negative, the gear shift is other than the gear shift to the second gear while the fifth gear is running, so step SS8 is performed.
In step S6, the shift command signal for obtaining the shift gear determined in step SS6 is a shift electronic control device 7
8 to the automatic transmission 14.

However, if the determination at step SS7 is affirmative, and if the kick-down operation condition for generating the abrupt driving force is detected at steps SS9 to SS12, the third gear is obtained at step SS13. The electronic control unit 78 for gear shift is output to the automatic transmission 14 to shift down from the fifth gear to the third gear.
If the kick-down operation condition for generating a sudden driving force is not detected by SS12 to SS12, step SS1
In step 4, the shift command signal for obtaining the second gear is output from the electronic shift control device 78 to the automatic transmission 14 to downshift from the fifth gear to the second gear.

In step SS9, it is determined whether or not the vehicle speed V is higher than a preset judgment reference value β, for example, about several tens of km / h, and in step SS10, a change rate Δθ of the throttle valve opening θth is set in advance. It is determined whether the throttle valve opening degree θth ^-1 in the previous cycle is smaller than a preset determination reference value, for example, 10 ° or 10%, in step SS11. It is determined, and in step SS12, it is determined whether or not the kick down switch 77 has been actuated. If the determinations at steps SS9 to SS12 are both affirmative, the step SS13 is executed, and if at least one of the determinations is negative, the step SS14 is executed.

According to this embodiment, when the actual gear stage established in the automatic transmission 14 is detected in step SS7 corresponding to the gear stage detecting means 90, the downshift gear stage determining means 92 is responded to. In steps SS9 to SS12, the gear stage to be downshifted is determined based on the actual gear stage so that the change ratio of the gear ratio due to the downshift does not exceed a predetermined value, and this downshift gear stage determination means 92. The gear shift command signal for obtaining the gear position determined by is output to the automatic transmission 14 in step SS13 corresponding to the gear shift control means 94. Therefore, also in this embodiment, it is possible to prevent the driving force of the vehicle from rapidly increasing beyond the driver's desire, and to obtain good drivability.

Although one embodiment of the present invention has been described above with reference to the drawings, the present invention can be applied to other modes.

For example, in the above-described embodiment, steps SS9 to SS12 are provided to determine the kickdown operation condition for generating a sudden driving force, but
It does not matter if the execution condition of step SS13 is relaxed by removing any of steps SS9 to SS11.

Further, although the automatic transmission 14 having five types of forward gear stages has been described in the above embodiment, the automatic transmission 14 having four types or six or more types of forward gear stages is also possible. It doesn't matter.

Although not exemplified one by one, the present invention can be carried out in various modified and improved modes based on the knowledge of those skilled in the art.

[Brief description of drawings]

FIG. 1 is a skeleton diagram illustrating a configuration of an automatic transmission for a vehicle in which a gear stage is controlled by a shift control device according to an embodiment of the present invention.

FIG. 2 is a table showing a relationship between a combination of operations of a plurality of friction engagement devices and gear stages established by the combination in the automatic transmission of FIG.

FIG. 3 is a block diagram illustrating a hydraulic control circuit and an electric control circuit for controlling the automatic transmission of FIG.

FIG. 4 is a diagram illustrating an operating position of a shift lever of FIG.

5 is a functional block diagram illustrating a main part of a control function of the electronic shift control device of FIG.

FIG. 6 is a flowchart for explaining a main part of control operation of the electronic shift control device of FIG.

FIG. 7 is a diagram showing a shift diagram used at the fifth speed in the D range in FIG. 6;

FIG. 8 is a diagram showing a shift line diagram used at the fourth speed gear stage of the D range in FIG. 6;

FIG. 9 is a diagram showing a normal shift diagram used in the D range in FIG. 6;

FIG. 10 is a view corresponding to FIG. 6 for explaining the operation of another embodiment of the present invention.

[Explanation of symbols]

 14: Automatic transmission 90: Gear stage detecting means 92: Downshift gear stage determining means 94: Shift control means

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yasuo Hojo 1 Toyota Town, Toyota City, Aichi Prefecture Toyota Motor Corporation (72) Inventor Masahiko Ando, Takane, Fujii Town, Aichi Prefecture Aisin AW (72) Inventor Masahiro Hayabuchi 10 Takane, Fujii-cho, Anjo City, Aichi Prefecture Aisin AW Co., Ltd. (72) Inventor Kazuma Tsukamoto 10 Takane, Fujii-cho, Anjo City, Aichi Prefecture W Co., Ltd.

Claims (1)

[Claims] 1. A shift control device for a vehicle automatic transmission having a plurality of forward gears, wherein the gear to be shifted is determined based on an actual engine load amount and a vehicle speed from a preset shift map. The gear ratio detection means for detecting the actual gear speed established in the automatic transmission, and the gear ratio change range due to the downshift based on the actual gear speed detected by the gear speed detection means. So as not to exceed a predetermined value, downshift gear stage determining means for determining a gear stage to be downshifted, and a shift command signal for obtaining the gear stage determined by the downshift gear stage determining means are the automatic shift A shift control device for an automatic transmission for a vehicle, comprising: