JPH061103B2 - Shift control device for automatic transmission - Google Patents

Description

Detailed Description of the Invention [Industrial applications]

The present invention relates to a shift control device for an automatic transmission, and more particularly, to an automatic shift control device capable of automatically switching a shift speed according to a shift pattern selected by a pattern select switch from at least two preset shift patterns. The present invention relates to improvement of a shift control device of a transmission.

[Prior art]

A gear shift mechanism and a plurality of friction engagement devices are provided, the engagement of the friction engagement devices is selectively switched by operating a hydraulic control device, and a plurality of shift stages are selected according to a preset shift map. An automatic transmission for a vehicle configured to achieve any of the above is already widely known. In this case, two or more patterns of the shift map are provided,
A wide variety of patterns are already available that allow the driver to arbitrarily select a shift pattern (generally referred to as P pattern) that emphasizes power performance or a traveling pattern (generally referred to as E pattern) that emphasizes fuel efficiency. Are known. Further, in such an automatic transmission for a vehicle, the engine torque is changed at the time of gear shifting to obtain good gear shifting characteristics, and the durability and the durability of the friction engagement device are secured and improved. Various integrated control devices have been proposed (for example, Japanese Patent Application No. 59-234466).

[Problems to be Solved by the Invention]

However, in the case of a shift that should originally be controlled to change the engine torque, for example, when the engine torque change control cannot be executed due to a sensor system trouble or a request from the engine side, frictional engagement on the automatic transmission side is performed. Since the amount of absorbed energy of the device increases, not only the durability of the friction engagement device is impaired, but also the gear shift time becomes long and the gear shift does not end in the buffer area of the accumulator, resulting in a large gear shift shock. To do. This is because, on the automatic transmission side, gear tuning specifications such as hydraulic pressure are set so that the engine torque is reduced by a predetermined amount during the gear shift. Further, irrespective of whether or not the engine torque change control at the time of gear shifting is performed, the gear shifting time becomes long even when the working hydraulic pressure is reduced due to oil leakage or the like, and the friction engagement device is operated. Adversely affects durability,
Further, the gear shift does not end in the buffer area of the accumulator, and a large gear shift shock occurs.

[Object of the Invention]

The present invention has been made in view of such a conventional problem, and when an abnormal gear shift is performed (becomes performed) for some reason, this is promptly detected,
An object of the present invention is to provide a shift control device for an automatic transmission, which can ensure the durability of a friction engagement device of the automatic transmission with a simple structure and can also secure good shift characteristics.

[Means for solving problems]

The present invention relates to a shift control device for an automatic transmission, which is capable of automatically switching a shift speed according to a shift pattern selected by a pattern select switch from among at least two preset shift patterns. As shown in the outline thereof, means for determining whether or not the shift is abnormal, and when the shift is determined to be abnormal, the shift pattern for the next shift is set to a low shift point. The above object is achieved by including means for forcibly changing to the shift pattern side.

[Action]

In the present invention, due to some reason such as a failure of the sensor system or a request from the engine side, the engine torque change control is supposed to be originally performed, but the engine torque change control is not actually executed and is abnormal. If a gear shift occurs, or if an abnormal gear shift occurs due to wear of the friction engagement device or a decrease in working hydraulic pressure, this is promptly detected and the gear shift pattern for the next gear shift is changed. The point is forcibly changed to the shift pattern side set to a low value. Therefore, the gear shift is performed earlier (while the vehicle speed is low, that is, while the inertia torque of the engine is small), and the energy related to the friction engagement device is reduced accordingly, and accordingly, the friction engagement device It will be possible to improve durability,
In addition, the shift time can also be accommodated within the buffer area of the accumulator, and it is possible to prevent the shift characteristics from deteriorating. Further, since this control uses one of the gear shift patterns already prepared for changing the gear shift pattern, it is extremely simple without increasing the ROM capacity of the computer. Therefore, it can be realized at a low cost. In a preferred embodiment, the means for judging the abnormality monitors the engine rotation speed and judges whether the time during which the engine rotation speed is decreasing is longer than a preset value. That is. Further, it is preferable that the abnormality determining means monitors the output shaft torque of the automatic transmission, and whether the time until the output shaft torque changes from the minimum value to the maximum value is longer than a preset value. That is, it is determined whether or not. Further, preferably, the means for judging the abnormality monitors the output shaft torque of the automatic transmission and judges whether or not the maximum value of the output shaft torque is larger than a preset value. It is that you are. As described above, the present invention does not limit the means for determining an abnormality. In this case, it is preferable that the preset value in each of the above means is changed according to the engine load, the type of gear shift, and the like. It is also preferable to issue a warning when the shift pattern is forcibly changed. As a result, the driver can immediately know that the gear shift abnormality has occurred for some reason, and for that reason, the driver knows that the vehicle is traveling in the gear shift pattern in which the shift point is set to a low value. be able to. Further, preferably, the forced change of the shift pattern is executed only when the engine load is equal to or more than a predetermined value. The advantages of doing this are as follows. That is, when the engine load is small, generally, the durability of the friction engagement device does not matter, and the gear shifting ends relatively early. Therefore, the present invention is particularly effective when the engine load is high to some extent. Therefore, there is no problem if the forced change of the shift pattern is executed only when the engine load is equal to or higher than a predetermined value, and when the engine load is equal to or lower than the predetermined value, the driver's intention is respected to improve the power performance. It is good because it is possible to drive with the shift pattern emphasized. Further, it is preferable that the forced change of the shift pattern is executed only for a shift having an abnormality. As a result, it is possible to respect the driver's intention with regard to a gear shift having no particular problem and to travel in a gear shift pattern with good power performance.

【Example】

Embodiments of the present invention will be described in detail below with reference to the drawings. FIG. 2 is an overall schematic diagram of a shift control device for an automatic transmission to which the present invention is applied. The engine 1 and the automatic transmission 2 are well known. In the engine 1, the engine control computer 7 controls the fuel injection amount in the injection valve 19 and the ignition timing in the distributor 20 to obtain an engine output corresponding to the accelerator opening and the engine rotation speed. Further, in the automatic transmission 2, the electromagnetic valves S _{1 to} S _{3 of the} hydraulic control device 3 are controlled by the automatic transmission control computer 8, and as a result of the oil passage in the hydraulic control device 3 being changed, each friction engagement device is changed. The engagement state is selectively changed so that a shift speed corresponding to the vehicle speed and the accelerator opening can be obtained. That is, the engine control computer 7 includes the engine rotation speed by the engine rotation sensor 9, the intake air amount by the intake amount sensor 10, the intake air temperature by the intake air temperature sensor 11, the throttle opening by the throttle sensor 12, and the vehicle speed by the vehicle speed sensor 13. , The engine water temperature from the engine water temperature sensor 14, and the brake ON signal from the brake switch 15 are input. The engine control computer 7 determines the fuel injection amount and the ignition timing based on these signals. The engine control computer 7 also receives in parallel the solenoid signals of the solenoid valves S _{1 to} S ₃ that are ON-OFF controlled by the automatic transmission control computer 8, thereby changing the speed of the automatic transmission. You are deciding when. On the other hand, to the automatic transmission control computer 8, signals from the throttle sensor 12, vehicle speed sensor 13, engine water temperature sensor 14, brake switch 15 and the like are added, and the position of the shift lever by the shift position sensor 16 and the pattern select switch 17 are added. A driving selection pattern such as a fuel economy-oriented driving or a power performance-oriented traveling is input, and a signal such as a shift permission to the overdrive by the overdrive switch 18 is input, so that the shift speed corresponding to the vehicle speed and the accelerator opening is obtained. The valves S _{1 to} S ₃ are ON / OFF controlled. FIG. 3 is a flowchart of integrated control of the engine and the automatic transmission. In this embodiment, the engine rotation speed Ne is monitored and the shift abnormality is judged by detecting the time during which the engine rotation speed Ne is decreasing. Each step will be described below. Step 100: It is determined whether or not a low speed shift pattern (see FIG. 4 (A)) for shifting in the low rotation range of the engine 1 is selected by the pattern select switch 17. Step 101; When step 100 is YES, the low speed shift pattern is set as selected by the pattern select switch 17. Step 102: When the low speed shift pattern is not selected (step 100 is NO), it is determined whether the flag F ₂ is 1 or not. The flag F ₂ is set to 1 at the time of the abnormal shift determination in step 120, and when F ₂ = 1 or when the abnormal shift actually occurs, a shift pattern other than the low speed shift pattern, for example, the high speed shift pattern (4th Figure (B)
Even if (see) is selected, the process proceeds to step 101 to set the low speed shift pattern. Step 103: If the low speed shift pattern is not selected and the flag F ₂ is not 1, the high speed shift pattern is set. Step 104: Shift determination is performed according to the shift pattern set in steps 101 and 103. Step 105: It is determined whether or not the flag F ₁ is zero. Since zero is initially set, the routine proceeds to step 106. Step 106: It is determined whether or not it is an upshift. Step 107: Command the solenoid valves S _{1 to} S ₃ to supply hydraulic pressure to the corresponding friction engagement device (shift command). Step 108: It is determined whether or not the power is ON (engine output is positive). Step 109: The engine rotation speed Ne is monitored to detect the shift start timing due to the upshift. Step 110: It is determined whether or not the detected engine speed Nei is smaller than the previously detected value Ne _i-1 . That is, it is determined whether the engine rotation speed Ne has started to decrease due to the upshift. In this case, even if the hydraulic pressure supply to the upshift frictional engagement device is started in step 107, normally the gear shift does not immediately start, so step 110 is initially NO and the routine proceeds to step 111. Step 111: After the hydraulic pressure supply command for the upshift is issued, the flag F ₁ indicating that the monitoring of the engine speed Ne is started is set to 1, and the number n of times Nei <Ne _i-1 is satisfied is set to zero. . Step 113; When Nei <Ne _i-1 is satisfied in Step 110, 1 is added to the number of times n is satisfied. Step 114; It is judged whether or not the number n of consecutive times of establishment of Nei <Ne _i-1 is a predetermined value n ₀ (for example, n ₀ = 3) or more. Yes
At this time, that is, when it is determined that the decrease in the engine rotation speed is not a temporary change in rotation but a decrease (change) in rotation due to an upshift, the shift start is recognized and the process proceeds to step 115. Step 115: At the same time when the engine output down command is output, a timer is started to measure the shift time t. Step 116: In order to detect the time when the shift is completed, Neo, which is set a little higher than Ne after the shift calculated in advance, is compared with Ne being monitored,
If Ne <Neo is not satisfied, it is determined that the shift is still in progress (engine output is down) and the routine proceeds to step 117. If Ne <Neo is satisfied, it is determined that the shift is about to end and step 11
Go to 8. Step 117: Set the flag F ₁ to 2. Step 112; Since it has been determined in step 105 that F ₁ = 0 is not satisfied, in this step, it is determined whether or not F ₁ is 1. When F ₁ = 1, the process proceeds to step 110 in order to determine whether gear shifting has started, and F ₁ =
When it is not 1, that is, when F ₁ = 2, the routine proceeds to step 116 in order to determine whether or not the shift is completed. Step 118: A command for returning the engine output is output just before the end of the shift, and the timer t for measuring the shift time is stopped. Step 119: The shift time t is compared with the abnormal shift determination time t ₀ preset by the type of shift, the throttle opening, and the shift point. When t ≧ t ₀ , the routine proceeds to step 120. Step 120: It is judged that an abnormal gear shift has been performed, and the flag F _{2 is set} to 1. When F ₂ = 1, even if the high speed shift pattern is selected by the pattern select switch 17 in step 102, the low speed shift pattern is forcibly switched in order to reduce the energy absorption amount of the friction engagement device. Step 121: A warning light is displayed to inform the driver that the gear shift pattern is fixed to the low speed gear shift pattern regardless of the pattern select switch 17 for the purpose of protecting the friction engagement device because of the abnormal gear shift. Step 122: The flag F ₁ , the number n of times Nei <Ne _i-1 is satisfied, and the shift time measurement value t are set to zero. Step 123: It is judged whether or not it is a downshift, and if yes, the routine proceeds to step 124. Step 124: A command for releasing the hydraulic pressure of the corresponding clutch is issued. Although not shown in the flowchart, the flag F ₂ is reset so that it is not reset unless the cause of the abnormal gear shift is eliminated, for example, when the battery terminal is OFF (released). FIG. 6 shows a shift transient characteristic when the above control flow is executed. The gear shift command b is executed after a predetermined time from the gear shift judgment a as in the conventional case. This is to cope with a so-called multiple shift. The engine output down command is slightly delayed from the actual shift start timing because the engine rotation speed Ne is monitored at the time point c ′ at which Nei <Ne _i-1 is repeated n times. The shift end time when the engine output control is normal is t ₂ , but the measured value in the above flow is t ₁ , and therefore,
Shift time t will be less measured by t ₂ -t _1. In the figure, t ₃ is the stroke end time (end time of the buffer area) of the accumulator piston installed in the oil passage to the friction engagement device. Since the actual shift time must be before this stroke end time, at least the abnormal shift determination time t ₀ must be smaller than t ₃ when the shift time measurement is used as the abnormal shift determination means. Further, as described above, in the case of the method of judging before the completion of the shift by Ne ₀ , the measurement is made smaller than the actual _value by t ₂ −t _1, so that finally t ₀ <t ₃ − (t _2-
The abnormal gear shift determination time t ₀ is set so as to be t ₁ ). The time start points from t _{1 to} t ₃ are all engine output down commands c ′, so the time lag that occurs first does not matter. The t
₃ may be obtained by design by the capacity of the accumulator, the orifice system, the line hydraulic pressure, or the like, or may be determined by taking experimental data. Measured value t ₄ when engine output control is abnormal
Becomes larger than t ₃ − (t ₂ −t ₁ ), and as a result, YES is determined in step 119. In the figure, when the engine output control is normally performed (solid line), the working hydraulic pressure of the friction engagement device is set to a low value in advance as compared to when the engine output control is not performed (two-dot chain line). Therefore, the fluctuation of the output shaft torque T of the automatic transmission is small. When the engine output control is not performed for some reason (broken line), the working oil pressure of the friction engagement device is low with respect to the load torque of the friction engagement device. rate)
Becomes smaller, the gear shift time t becomes longer, and it takes t ₄ to cause an extremely large shock after the stroke end of the accumulator piston. According to the above-described embodiment, this abnormality is detected by the length of the shift time t, and even if the shift pattern in which the shift point is set higher is selected by the pattern select switch 17, this is forced to shift. Since the gear shift pattern is set to a lower point, the gear shift is performed in a region where the inertia torque of the engine is small, so that the heat load of the friction engagement device at the time of gear shift is reduced. It is possible to improve the durability of the gear shift, the gear shift time t is shortened, and a large gear shift shock can be prevented. Further, in this case, the alarm device allows the driver to know the abnormality, so that it is possible to avoid the discomfort caused by the low shift point and promptly check the cause of the failure. become able to. It should be noted that, in the present invention, when an abnormal gear shift is detected, even if the gear shift pattern set to the higher gear is selected by the pattern select switch, the gear shift pattern set to the lower gear shift pattern side is changed. It was done. Therefore, theoretically, if the pattern select switch originally selects a shift pattern with a lower shift point, the shift pattern does not particularly function. However, when considering the reality, in the shift pattern when the shift point is set to a low value, the heat load of the friction engagement device is not so large in the first place, so that the shift is performed after the stroke end of the accumulator piston. It is unlikely to last for a long time, and it is considered that there is no problem in practical use. According to the present invention, since it is not necessary to prepare a shift map separately set for abnormal conditions in advance, there is an advantage that there is almost no cost increase in implementation. In the above embodiment, the shift time t is longer than t ₀ and is judged to be an abnormal shift only once. However, it is not easily judged to be an abnormal shift within the range of variation. As described above, when t ≧ t ₀ is satisfied a certain number of times, it may be determined that the gear shift is abnormal. Further, the change of the shift pattern may be limited to only the shift in which the shift abnormality has occurred. Alternatively, the shift pattern may be changed only when the throttle opening is large, which causes the durability of the friction engagement device to be a problem. Further, in the above embodiment, in determining the gear shift abnormality, the engine rotation speed is monitored and it is determined whether the time during which the engine rotation speed is decreasing is longer than a preset value. However, the present invention is not limited to this. For example, the output shaft torque T of the automatic transmission is monitored, and the output shaft torque T is the minimum value T ₁
It may be determined whether or not the time from the change to the maximum value T ₂ (t ₅ in the shift characteristic diagram of FIG. ₅ ) is longer than a preset value. Further, the output shaft torque T of the automatic transmission is monitored, and the maximum value T of the output shaft torque T
_It may be possible to determine whether ₂ (see also FIG. 5) is larger than a preset value T ₀ .

【The invention's effect】

As described above, according to the present invention, when a gear shift abnormality occurs for some reason, the gear shift time becomes long, the durability of the friction engagement device deteriorates, or the gear shift shock becomes large, From the next shift onward, regardless of the position of the pattern select switch, the shift point will be shifted according to the shift pattern set to a lower shift point, so the heat load on the friction engagement device can be reduced with a simple configuration. It is possible to obtain the excellent effect that the gear shift time can be kept within the piston stroke end of the accumulator, and the gear shift shock can be reduced.

[Brief description of drawings]

FIG. 1 is a block diagram showing the gist of the present invention, and FIG.
FIG. 3 is an overall block diagram of an automatic transmission for a vehicle and an engine showing a configuration of an embodiment of a shift control device for an automatic transmission according to the present invention. FIG. 3 is a flow chart showing a control routine adopted in the embodiment device. 4 (A) and (B) are diagrams showing the same shift pattern example, and FIG. 5 is a shift transient characteristic diagram when the above control routine is executed. 1 ... Engine, 2 ... Automatic transmission, 7 ... Engine control computer, 8 ... Automatic transmission control computer, t ... Shift time, T ... Output shaft torque.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Fumiaki Izumi 1 Toyota Town, Toyota City, Aichi Prefecture Toyota Motor Corporation (56) Reference JP-A-58-225249 (JP, A) JP-A-62-188844 (JP, A)

Claims (8)

[Claims] 1. A shift control device for an automatic transmission, wherein a shift stage can be automatically switched in accordance with a shift pattern selected by a pattern select switch from at least two preset shift patterns. Means for determining whether or not there is an abnormality, and means for forcibly changing the shift pattern in the next shift to the shift pattern side having a lower shift point when it is determined that the shift is abnormal. A shift control device for an automatic transmission, comprising: 2. The abnormality determining means monitors the engine rotation speed and determines whether the time during which the engine rotation speed is decreasing is longer than a preset value. 5. A shift control device for an automatic transmission according to claim 1. 3. The means for judging the abnormality monitors the output shaft torque of the automatic transmission, and whether the time until the output shaft torque changes from the minimum value to the maximum value is longer than a preset value. The shift control device for an automatic transmission according to claim 1, which determines whether or not the shift control is performed. 4. A means for judging the abnormality, wherein the output shaft torque of the automatic transmission is monitored and it is judged whether or not the maximum value of the output shaft torque is larger than a preset value. A shift control device for an automatic transmission according to claim 1. 5. The preset value is an engine load,
The shift control device for an automatic transmission according to any one of claims 2 to 4, wherein the shift control is changed depending on at least one of the types of shifts. 6. A shift control device for an automatic transmission according to any one of claims 1 to 5, wherein a warning is issued when the shift pattern is forcibly changed. 7. The automatic transmission according to claim 1, wherein the forced change of the shift pattern is executed only when the engine load is a predetermined value or more. Shift control device. 8. The first range according to claim 1, wherein the forcible change of the shift pattern is executed only for abnormal shifts.
Item 8. A shift control device for an automatic transmission according to any one of items 7 to 7.