JPH0362940B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of controlling an automatic transmission for a vehicle. Automatic transmissions for vehicles have conventionally been equipped with a hydraulic circuit including a hydraulic switching valve that is switched based on the balanced relationship between the governor hydraulic pressure, which increases as the vehicle speed increases, and the throttle hydraulic pressure, which increases as the throttle opening increases. The gears are controlled and can be switched between a plurality of gear stages based on the interrelationship between the vehicle speed and the throttle opening value. In this case, the shift lines that define the switching boundaries between multiple gears are usually expressed in rectangular coordinates with the horizontal axis representing the vehicle speed and the vertical axis representing the throttle opening. Regarding switching between two adjacent gears such as 2nd speed and 3rd speed, one way is defined for each upshift and downshift. Such conventional transmission lines are capable of switching between multiple gears when the vehicle is operated in most standard driving conditions.
It is designed to achieve a balance between the vehicle's power performance and fuel efficiency.

However, when gear changes in automatic transmissions are always performed according to such a standard speed pattern, dissatisfaction can sometimes be felt when higher output performance is required. Even if the output performance is set, there are many operating conditions in which there is no substantial problem in the output performance.

Further, when an automatic transmission for a vehicle includes a direct coupling clutch that directly couples a torque converter, the direct coupling clutch is conventionally engaged only when the gear transmission mechanism is set to the highest speed gear. However, even with such a direct coupling clutch, in order to further improve the fuel efficiency of the vehicle, the direct coupling clutch may be engaged even when the gear transmission mechanism is set to a gear other than the highest speed.
Additionally, regarding the switching pattern that determines switching between engagement and disengagement of the direct coupling clutch, there are differences between when the vehicle is driven with priority given to output performance and when it is driven with priority given to fuel efficiency performance. When the switching pattern is used, there should be an appropriate difference in the switching pattern.

The present invention addresses the above-mentioned problems with conventional automatic transmissions for vehicles, and changes the state from a state in which a vehicle should be driven with priority given to output performance to a state in which it should be driven with priority given to fuel efficiency. In order to obtain an automatic transmission for a vehicle that has shifting characteristics that are better suited to a wide range of driving conditions, we will discuss when a vehicle should be driven with priority given to output performance and when the vehicle should be driven with priority given to fuel efficiency performance. Different patterns are prepared for changing the gear transmission mechanism and engagement or release of the direct coupling clutch depending on the time, and the driver is allowed to select and use these as appropriate according to his/her will. Even when the driver has selected a pattern that prioritizes fuel efficiency, if the driver rapidly depresses the accelerator pedal beyond a certain predetermined speed, the pattern is automatically switched to a pattern that prioritizes output performance. It is an object of the present invention to provide a control method for an automatic transmission for a vehicle that achieves rapid acceleration of a vehicle that responds well to rapid depression of an accelerator pedal.

According to the present invention, it is an object of the present invention to provide a method for controlling an automatic transmission for a vehicle, which includes a torque converter, a gear transmission mechanism that is switched between a plurality of gears, and a direct coupling clutch that directly couples the torque converter. The gear transmission mechanism is switched between the plurality of gears based on a plurality of input signals including a signal related to the amount of accelerator pedal depression, and the direct coupling clutch is switched between engagement and disengagement. and a shift line that defines a switching boundary between the plurality of gears based on the value of the accelerator pedal depression amount, and a direct coupling that defines a switching boundary between engagement and disengagement of the direct coupling clutch based on the vehicle speed and the value of the accelerator pedal depression amount. The clutch switching line is set to a plurality of patterns including a first pattern which is preferable mainly from the viewpoint of output performance and a second pattern which is preferable mainly from the viewpoint of fuel economy performance, and a predetermined pattern from among the plurality of patterns is operated at any time. Even when the driver selects a pattern other than the first pattern, if the rate of increase in the amount of accelerator pedal depression is greater than or equal to a predetermined value, the selection by the driver is performed. This is achieved by a control method characterized by selecting the first pattern over and above the other.

The invention will now be described in detail by way of example embodiments with reference to the accompanying drawings.

FIG. 1 is a schematic diagram showing the configuration of an apparatus for carrying out the method of controlling an automatic transmission for a vehicle according to the present invention. As shown in the figure, in order to implement the control method of the present invention, an automatic transmission control computer 100 is used.
The computer is adapted to receive several input signals and to produce several output signals for automatic transmission control. In the illustrated embodiment, the computer 100 receives a signal from the knock sensor 1 indicating whether or not a knock is occurring in the engine.
A signal related to the vehicle speed is sent from the vehicle speed sensor 2, a signal related to the throttle opening is sent from the throttle sensor 3,
The engine water temperature sensor 4 sends a signal related to the engine water temperature, and the altitude sensor 5 sends a signal related to the altitude.
A shift position sensor 6 supplies a signal related to the shift position, a pattern select switch 7 supplies a pattern select signal indicating which pattern is selected, and a brake sensor 8 supplies a signal related to brake operation. . Furthermore, the automatic transmission control computer 100 is configured to receive signals relating to the engine control state and the autodrive operating state from an engine control computer 101 and an autodrive computer 102, respectively.

In addition, the throttle opening is a value that represents the engine torque in a throttle-controlled engine.
More generally, for engines using various output control methods, this corresponds to the amount of accelerator pedal depression.

Based on these input signals, the automatic transmission control computer determines which gear the gear transmission mechanism should be set to, and whether the direct coupling clutch should be engaged or disengaged, in the manner described below. , displays this on the display device 9, and at the same time selectively turns on (energizes) or turns off (de-energizes) the solenoids 11 and 12 for changing the gear stage of the gear transmission mechanism and the solenoid 13 that engages or releases the direct coupling clutch. do.

A shift control device for an automatic transmission for a vehicle, which is switched between four gear stages of first gear, second gear, third gear, and fourth gear (overdrive) using these two solenoids 11 and 12, is disclosed in the present application. This was proposed in Japanese Patent Application No. 55-69110 filed by the same applicant. Figure 2 shows the shift position set by the manual switching valve in the shift control device of an automatic transmission for vehicles, which will be proposed later, and the solenoids 11 and 12 for each gear stage obtained under the shift position. 2 is a table showing the on/off state of the solenoid 13 and the on/off state of the solenoid 13 for engagement and release of the direct coupling clutch. In this case, the automatic transmission is in D range 4th speed and S range 2nd speed.
When the vehicle is set to the second speed, L range, second speed, and first speed, the engine brake can be applied.

The manner in which the control method of the present invention is carried out by the control device having the configuration shown in FIG. 1 will be explained below using a flowchart.

FIG. 3 is a diagram showing the arrangement relationship between each divided diagram of a flowchart divided into FIGS. 3a, 3b, 3c, 3d, and 3e,
If these figures 3a to 3e are combined as shown in figure 3, the entire flowchart can be expressed.

As shown in FIG. 3a, control of the automatic transmission begins at the start of step 1, with the automatic transmission control computer 100 being reset to an initial state. Starting from this starting state, the following judgment or selection operation will be repeated continuously, but the time required for one cycle is about 5 mmsec, so the automatic transmission can perform any operation while the vehicle is driving. At each point in time, a control state corresponding to the operating state approximately at that moment is set.

When the automatic transmission control computer 100 is reset to the initial state by the start, data is then input to the computer in step 2. The data input here includes data regarding whether or not the engine is in a knock state, which is generated by the knock sensor 1, data regarding the vehicle speed which is generated by the vehicle speed sensor 2, data regarding the throttle opening level which is generated by the throttle sensor 3, and engine water temperature. data regarding the engine water temperature emitted from the sensor 4, data regarding the altitude emitted from the altitude sensor 5, data regarding the shift position emitted from the shift position sensor 6, data regarding the selected pattern emitted from the pattern select switch 7,
Data regarding brake operation issued by brake sensor 8, engine control computer 1
01 regarding the engine control, and data regarding the auto drive issued from the auto drive computer 102.

Next, in step 3, a shift position is determined. Shift position is P, R, N
When either of the solenoids 11, 12,
13 are turned off, and the flow in the flowchart immediately returns to the point before data input.

If the shift position is set to the L range, the L range pattern, which is the only control pattern for the L range, is selected (step 5).

When the shift position is in the S range or the D range, the next step 4 is to determine whether the control pattern selected by the pattern select switch 7 is the P pattern or the E pattern.
Moreover, when neither of these patterns exists, the R pattern is used. The pattern select switch 7 includes a push button for selecting the P pattern and a push button for selecting the E pattern. (Push button structures of this type are known) and the P or E pattern is selected depending on which of these two push buttons is pressed. It is determined that the R pattern is selected based on the fact that neither button is pressed.

When the P pattern is selected in the S range, the S range P pattern is selected, and when the E pattern is selected in the S range, the S range E pattern is selected, and the P pattern is also selected in the S range. When no pattern is selected, that is, when it is determined that the R pattern is selected, the S range R pattern is selected (step 5). P
The pattern is a control pattern that prioritizes output performance, the E pattern is a control pattern that prioritizes fuel economy performance, and the R pattern is an intermediate control pattern between P pattern and E pattern.

When the P pattern is selected in the D range, then in step 5, the engine water temperature is lower than a predetermined first temperature _T1 , or is set to a second predetermined temperature _T2 higher than _T1 . is between or T ₂
A judgment will be made as to whether it is higher. When the engine water temperature is below T ₁ , the D range PT ₁ pattern is selected, and when the engine water temperature is between T ₁ and T ₂ , the D range PT ₂ pattern is selected, and when the engine water temperature is above T ₂ . Sometimes D range basic P
A pattern is selected (step 6).

The D range basic P pattern is, for example, as shown in FIG. Figure 4 shows vehicle speed on the horizontal axis.
FIG. 4 is a diagram showing a shift line between each gear stage and a switching line between engagement and release of a direct coupling clutch, with the throttle opening degree taken on the vertical axis. In this diagram, the shift line 1→2 is an upshift line that changes from the first speed gear to the second speed gear, and the shift line 1←2 is an upshift line that changes from the second speed gear to the first speed gear. This is the downshift line where the downshift is performed. Similarly, shift lines 2→3 and 2←3 are upshift lines and downshift lines between the second and third speed stages, respectively, and shift lines 3→4 and 3←4 are respectively at the third speed. tier and 4th
Upshift line and downshift line between speed gears (overdrive). in this case,
Since this diagram is for the P pattern, it should be understood that the shift line is generally biased toward higher vehicle speeds than for the E pattern.

Furthermore, in the diagram of FIG. 4, a switching line for engaging or disengaging the direct coupling clutch is shown superimposed on the transmission line. In this diagram, the switching line
4thCLon is a switching line indicating the limit at which the direct coupling clutch is switched from the released state to the engaged state when the gear transmission mechanism is set to the fourth speed stage. Conversely, the switching line 4thCLoff is a switching line that indicates the limit at which the direct coupling clutch can be switched from the engaged state to the released state when the gear transmission mechanism is at the fourth speed. Similarly switching line 3rdCLon and
3rdCLoff is a switching line indicating the limit at which the direct coupling clutch can be switched from disengaged to engaged and from engaged to disengaged when the gear transmission mechanism is set to the third speed stage, and the switching lines 2ndCLon and 2ndCLoff are respectively This is a switching line indicating the limit at which the direct coupling clutch can be switched from disengagement to engagement and from engagement to disengagement when the gear transmission mechanism is set to the second speed stage.

The D range PT ₂ pattern described above is based on the shift line 3→4 from the D range basic P pattern as shown in Figure 4.
and 3←4 may be eliminated, and the pattern may be modified so that the direct coupling clutch is always released. Furthermore, the D range PT ₁ pattern described above is based on the D range basic P pattern as shown in FIG.
It may be modified to eliminate 3←4, 2→3, 2←3 and to keep the direct coupling clutch always released.

The S range P pattern described above may be similar to the D range PT ₁ pattern, and the S range E pattern may be similar to the D range PT ₂ pattern.

When it is not a P pattern in the D range, it is determined that it is an E pattern or an R pattern.
In this case, the speed of increase in throttle opening (Δθ/Δt)
When is greater than the predetermined value α, it is determined that the driver actually requires shift control using the P pattern, regardless of the selection state of the pattern select switch 7, and the P pattern is selected. Similarly, when the altitude H at which the vehicle is located is higher than the predetermined altitude _H0 , the output performance needs to be compensated to compensate for the thinning of the air. The P pattern is selected over the above (step 4).

When the E pattern is selected under the D range, the engine coolant temperature must be below T ₁ , between T ₁ and T ₂ , or above T ₂ , just as when the P pattern is selected. A determination is made as to whether the condition is present, and the D range ET ₁ pattern, D range ET ₂ pattern, or D range basic E pattern is selected accordingly.

Similarly, under the D range, when neither the P pattern nor the E pattern is selected, a decision is made to select the R pattern, and in this case as well, it is determined whether the engine water temperature is below T ₁ or between T ₁ and T ₂ . is between T ₂
Depending on the higher level, D range RT ₁ pattern, D
Either the range RT ₂ pattern or the D range basic R pattern is selected.

The various patterns selected under the D range E pattern are set in a similar manner, but in this case each shift line is generally biased toward a lower vehicle speed than the corresponding shift line in the P pattern.
Various patterns selected below the D range R pattern are also set in a similar manner, but their contents are intermediate between the corresponding P pattern and E pattern.

Each of these patterns depends on whether it is a P pattern, an E pattern, or an R pattern, and under what range setting it is carried out, especially the range in which engine braking is applied. In order to achieve preferable gear shifting of the gear transmission mechanism and preferable engagement or disengagement of the direct coupling clutch under each condition, depending on whether or not the engine is warmed up at that time. , which can be appropriately designed with experimental research.

The switching between engagement and disengagement of the direct coupling clutch is incorporated into each pattern in combination with the switching of the gear speed of the gear transmission mechanism, but in the P pattern, the ratio of the driving force by the torque converter to the driving force by the direct coupling clutch is is smaller than 1 and the vehicle speed is above a predetermined vehicle speed, the direct coupling clutch is engaged, and in the E pattern, the ratio of the driving force by the torque converter to the driving force by the direct coupling clutch is smaller than 1.3 and the vehicle speed is above a predetermined vehicle speed. Engage the direct coupling clutch when
In the R pattern, the ratio of the driving force from the torque converter to the driving force from the direct clutch is 1.1.
It is preferred that the direct coupling clutch is smaller and that the direct coupling clutch is engaged when the vehicle speed is above a predetermined speed.

When the pattern for changing the gear speed of the gear transmission mechanism and changing the engagement and release of the direct coupling clutch is thus selected, the current vehicle speed V is determined in step 7.
is smaller than the vehicle speed V _i-1 for downshifting to a gear position one gear lower than the current gear gear for the current throttle opening, and whether the current vehicle speed V is one gear lower than the current gear gear for the current throttle opening. Upshifting to a higher gear It is determined whether the vehicle speed is greater than V _i-1 , and when V≦V _i-1 or V≧V _i+1 , the direct coupling clutch is released at the same time as the shift is commanded. Then, when a predetermined time _Δt1 has elapsed (step 8), a downshift or an upshift is performed (step 9). In step 7, V becomes V _i-1
and V _i+1 , the gear transmission mechanism is held at the current gear position. Further, even if it is determined in step 7 that a downshift or upshift is to be performed, the downshift or upshift will not be performed until the time _Δt1 has elapsed after the direct coupling clutch is released. This is because it takes a certain amount of time to release the direct coupling clutch, and if a downshift or upshift is performed before that time, a shift shock may occur.

The next step 10 is for controlling the autodrive. If Autodrive is not activated, this step will be passed through. If Auto Drive is activated, and the difference between the predetermined vehicle speed set in Auto Drive and the actual vehicle speed is greater than a predetermined value, and the vehicle speed does not increase any further, the Auto Drive computer 102 is an automatic transmission control computer 10
0, a signal to cancel autodrive is emitted. In step 10, the presence or absence of this autodrive cancel signal is determined, and if this signal is present, a downshift from the fourth speed stage to the third speed stage is performed.

Then, in step 11, a determination is made as to whether the brake is being applied, and if the brake is being applied, steps 12, described below, are performed.
Bypass steps 13 and 14 and reach the entrance of step 15.
The direct coupling clutch is released regardless of other conditions.

In step 12, it is determined whether the throttle opening degree θ is zero, that is, whether the throttle valve is fully closed. If the throttle valve is fully closed, the process directly proceeds to step 15. As a result, the clutch is released. This is because if the direct coupling clutch is engaged even when the throttle valve is fully closed, when the accelerator pedal is depressed and the throttle valve is opened, engine torque fluctuations will be applied directly to the vehicle body mechanically through the direct coupling clutch. This is to prevent shocks from occurring due to transmission.

If it is determined in step 12 that the throttle opening is not zero, the vehicle speed V at that time is less than or equal to the limit vehicle speed Vd for direct coupling clutch release for the gear position at that time, or the vehicle speed V at that time is lower than the limit vehicle speed Vd for releasing the direct coupling clutch for the gear position at that time. A determination is made as to whether the vehicle speed is higher than the limit vehicle speed Ve for direct coupling clutch engagement. When the vehicle speed V is less than the release limit vehicle speed Vd, the process immediately goes to step 15.
The direct coupling clutch is released. When the vehicle speed V is equal to or higher than the engagement limit vehicle speed Ve, it is determined whether a time period Δt ₂ has elapsed since the upshift or downshift was performed, and the engine is still in a knocking state after the elapse of this time period. A determination is made as to whether or not this occurs, and the direct coupling clutch is engaged only when the time period has elapsed and no knocking has occurred.

Next, the necessary data regarding the results of the above judgment, selection, and command processes are outputted (step 16), and it is further checked whether or not the output has been performed as instructed (step 17), and the flow chart is as follows. You will be returned to the point before data entry. At this time, if the output is not in accordance with the command, a diagnosis display is performed to indicate the location of the defect and its cause.

The scanning process according to this flowchart is 5 mm.
By repeating this process at a cycle of approximately 100 seconds, the automatic transmission is controlled to constantly respond to changes in the driving condition of the vehicle.

Although the present invention has been described in detail with respect to one embodiment above, the present invention is not limited to this embodiment, and various other modifications can be made within the scope of the present invention. will be clear to those skilled in the art.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing one embodiment of a device for carrying out the control method for an automatic transmission for a vehicle according to the present invention, and FIG. A table showing the on/off state of the solenoid for each shift position and gear at the same time as that for the direct coupling clutch.
3a to 3e are partial flowchart diagrams showing each part of a flowchart showing one embodiment of the control method of the present invention;
The figure shows an example of the shift line for the gear transmission mechanism and the switching line for the direct clutch.
It is a diagram showing a pattern. 100... Computer for automatic transmission, 101
... Engine control computer, 102 ... Auto drive computer, 1 ... Knock sensor, 2 ... Vehicle speed sensor, 3 ... Throttle sensor, 4 ... Engine water temperature sensor, 5 ... Altitude sensor, 6 ... Shift Position sensor, 7... Pattern select switch, 8... Brake sensor,
9... Display device, 11, 12, 13...
solenoid.

Claims (1)

[Claims] 1. A method for controlling an automatic transmission for a vehicle, which includes a torque converter, a gear transmission mechanism that is switched between a plurality of gears, and a direct coupling clutch that directly connects the torque converter, the method comprising a plurality of signals that include a vehicle speed and an accelerator pedal depression amount. The gear transmission mechanism is switched between the plurality of gears based on the input signal of the gear shift mechanism, and the direct coupling clutch is switched between engagement and disengagement based on the vehicle speed and the amount of accelerator pedal depression. A shift line that defines a switching boundary between the plurality of gears and a direct coupling clutch switching line that defines a switching boundary between engagement and disengagement of the direct coupling clutch based on the vehicle speed and the amount of accelerator pedal depression are mainly used to determine the output performance. A plurality of patterns are set including a first pattern which is preferable from the viewpoint of fuel efficiency and a second pattern which is preferable mainly from the viewpoint of fuel efficiency, and a predetermined pattern from the plurality of patterns is selected at any time by a selection button operated by the driver. Even when the driver selects a pattern other than the first pattern, if the rate of increase in the amount of accelerator pedal depression exceeds a predetermined value, the first pattern is selected over the driver's selection. A control method characterized by: