JP3222175B2 - Transmission control device for automatic transmission - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic system which supplies or discharges a hydraulic pressure to or from a friction engagement device at the time of gear shifting so that the actual gear shifting characteristic of the automatic transmission becomes the target gear shifting characteristic determined from the output torque of the prime mover. The present invention relates to a shift control device for an automatic transmission that performs learning control.

Conventionally, for example, in Japanese Patent Application Laid-Open No. 2-150559, a time required for a shift of an automatic transmission is detected,
There is disclosed a technology in which the hydraulic pressure supplied to the friction engagement device is learned and controlled such that the required shift time coincides with a target shift time determined according to the output state of the prime mover.

When such learning control is executed, if the output torque of the prime mover changes during shifting, how to set a target shift time to be determined according to the output torque becomes a problem. . This is because, depending on the setting of the target shift time, the learning control may rather deteriorate the shift characteristics.

In this regard, Japanese Patent Application Laid-Open No. 2-15055 discloses
No. 9 proposes that the target shift time is determined according to the average value of the output state of the prime mover during shifting.

Further, in Japanese Patent Laid-Open No. 2-150559, the "difference" in the throttle opening during gear shifting greatly changes beyond the maximum allowable learning value .theta.set, while adopting such an average value configuration. In such a case, a technique has been proposed in which learning control itself is prohibited to avoid erroneous learning.

On the other hand, in Japanese Patent Application Laid-Open No. 2-42265,
For example, the torque input to the automatic transmission differs between when the engine auxiliary equipment load such as air conditioner is applied and when it is not, so that the engine auxiliary equipment is used to prevent erroneous learning. A technique for regulating the learning control in accordance with the state of the machine load has been proposed.

Further, in Japanese Patent Application Laid-Open No. 2-57438, depending on the vehicle, the engine torque is positively changed (reduced) when a predetermined condition is satisfied in order to improve the shift characteristics. In such a vehicle, the characteristics of the engine torque with respect to the throttle opening also differ, so a technique is disclosed in which learning control is restricted to prevent erroneous learning.

Incidentally, the detection of the output torque of the engine is an essential parameter in order to properly execute the shift control of the automatic transmission as described above. The fact is that it is difficult. For this reason, conventionally, a method of indirectly detecting the output torque by detecting the throttle opening has been widely adopted.

Recently, as the number of vehicles in which fuel injection of the engine is controlled electronically increases, Q / N (engine 1) instead of throttle opening is used as a parameter representative of output torque. An increasing number of examples adopt a method of estimating an engine output based on an intake air amount per revolution), a PM (intake pipe negative pressure), and utilizing the output for controlling a transmission (Japanese Patent Application Laid-Open No. 53-53). 85263, JP-A-61
-10816).

As described above, the method of indirectly detecting the output torque of the prime mover based on signals such as Q / N and PM is generally considered to have higher accuracy than the method of indirectly detecting the output torque based on the throttle opening. .

[0011]

However, Q /
Even in the case where the output torque of the prime mover is estimated using signals such as N and PM, in order to prevent erroneous learning due to this, the engine estimated from Q / N, PM, etc., as in the above-described disclosed technology. The learning may be established only when the change in the output is small, or in this case, the state of the auxiliary load of the engine, the state in which the (active) change of the engine torque can be executed, or the like may be considered. However, in estimating the output torque of the prime mover based on the load of the prime mover such as the throttle opening, Q / N, and PM, there is a problem that such a measure is not sufficient in practice.

When the output torque is estimated from signals such as the throttle opening, Q / N, PM, etc., an error occurs between the estimated output torque and the actual output torque. This is because the magnitude is not taken into account, and even if the estimated output torque is small, it includes a large error and the actual output torque is large, and there is a possibility that erroneous learning may occur depending on such an error.

SUMMARY OF THE INVENTION The present invention has been made in view of such a problem, and it is an object of the present invention to perform learning control in estimating the output torque of a prime mover based on the load of the prime mover in consideration of the influence of an error that occurs. As a result, it is possible to always execute appropriate learning control.For example, a shift is always performed with a predetermined shift characteristic even if there is a variation in the product of the line pressure control element or a temporal change of the friction material. Is the task to be solved.

[0014]

[0015]

According to the present invention, as shown in FIG. 1 (B), the hydraulic pressure supplied to or discharged from the friction engagement device during gear shifting is learned and controlled in accordance with the output torque of the prime mover. In the shift control device for an automatic transmission, a means for detecting an actually executed shift characteristic of the automatic transmission, a means for indirectly detecting an output torque of the prime mover based on a load of the prime mover, and the indirect detection Means for obtaining a target shift characteristic from the output torque of the prime mover, means for learning and controlling the oil pressure so that the shift characteristic matches the target shift characteristic, and when executing the learning means, the air-fuel ratio of the prime mover by providing means for maintaining below the stoichiometric air fuel ratio, a, is obtained by achieving the above Symbol purpose.

[0016]

When the air-fuel ratio is lean and when the air-fuel ratio is rich, even if the throttle opening, Q / N, PM, etc. are the same, the output is significantly different.

Generally, when the air-fuel ratio is in a so-called rich state below the stoichiometric air-fuel ratio, the throttle opening, Q /
Although the estimated output torque of the engine based on N or PM and the actual output torque match well, when the air-fuel ratio is lean, this correspondence tends to be broken.

[0018]

The present invention, in consideration of this point, when executing the learning control was to maintain below actively stoichiometric air-fuel ratio of the engine (claim 1).

As a result, very accurate learning can be performed, and erroneous learning can be prevented.

In the present invention, the output torque of the prime mover is Q
/ N, or particularly effective in a vehicle that estimates based on PM, etc., but also has a corresponding effect in a vehicle that indirectly detects the output torque of the prime mover according to the throttle opening, for example. The method of indirect torque detection itself is not particularly limited.

The present invention is particularly effective in a vehicle such as a lean-burn engine that actively runs in a lean state, but the present invention is also applicable to a vehicle using a general engine. Therefore, the present invention is not particularly limited to a vehicle equipped with a lean burn engine.

Further, the present invention is applicable to a shift in which particularly precise control (such as a so-called clutch-to-clutch shift) is required to simultaneously engage and disengage two friction engagement devices. When applied, it has a big effect,
A reasonable effect can be obtained even during normal shifting,
Therefore, the present invention does not limit the type of shift.

[0024]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 2 is an overall schematic diagram of an integrated control device for an automatic transmission and an engine to which the present invention is applied.

The engine control computer 20 controls the fuel injection amount of the injection valve 11 and the ignition timing of the distributor 12 to correspond to the accelerator opening (operating amount) of the accelerator pedal 30 and the engine speed. Engine power can be obtained.

That is, a main throttle valve 41 which opens and closes in conjunction with the movement of the accelerator pedal 30 and a motor driven by a command from the engine control computer 20 irrespective of the accelerator pedal 30 are provided in the intake pipe 40 of the engine 10. A sub-throttle valve 43, which is opened and closed in conjunction with the movement of 42, is arranged in series.

Since the main throttle valve 41 is directly connected to the accelerator pedal, the accelerator operation amount and the engine output directly correspond to each other. However, the opening of the sub throttle valve 43 can be set freely. Thus, a throttle opening with intended characteristics as a whole can be obtained. Specifically, since they are in series, they are governed by the smaller opening of the two.

The sub-throttle valve 43 is for arbitrarily controlling the engine torque for another purpose. Although not directly related to the present invention, the sub-throttle valve 43 changes the engine torque during gear shifting. In this case, the learning control is prohibited by the signal.

Signals from various sensor groups 50 are input to the engine control computer 20.

Specifically, this signal includes the engine speed by the engine speed sensor 50A, the intake air amount by the intake air amount sensor 50B, the intake air temperature by the intake air temperature sensor 50C, and the accelerator by the accelerator opening sensor 50D. Opening, vehicle speed (output shaft rotation speed) by vehicle speed sensor (output shaft rotation sensor of automatic transmission) 50E, engine water temperature by engine water temperature sensor 50F, oxygen sensor 50K
, The signals of the brake ON by the brake switch 50G, etc. are input.

From the intake air amount Q and the engine speed N, Q
/ N is required. Further, the air-fuel ratio A / F is obtained from the oxygen concentration.

The engine control computer 20 determines the fuel injection amount and the ignition timing based on these signals. In addition, control is performed so that the air-fuel ratio becomes a predetermined value.

On the other hand, various signals are also input to the automatic transmission control computer 70 for controlling the automatic transmission 60. Specifically, the accelerator opening sensor 50
D, in addition to the signals from the vehicle speed sensor 50E, the engine coolant temperature sensor 50F, the brake switch 50G, etc., the position of the shift lever by the shift position sensor 50H, and the travel selection pattern such as the fuel efficiency-oriented travel or the power performance-oriented travel by the pattern select switch 50I. , And an air conditioner ON / OFF signal by the auxiliary device sensor 50L are input.

Thus, the solenoid valve S of the hydraulic control device 80
1 to S4 and SLN, SLT, SLU are controlled,
As a result of the change of the oil passage in the hydraulic control device 80, the engagement state of each friction engagement device is selectively changed, so that the shift speed corresponding to the vehicle speed and the accelerator opening can be obtained smoothly. I have.

FIG. 3 is a skeleton diagram showing a specific example of the automatic transmission 60 described above. The automatic transmission 60 includes a torque converter 111, a subtransmission unit 112, and a main transmission unit 11
3 is provided.

The torque converter 111 has a lock-up clutch 124. The lock-up clutch 124 is provided between a front cover 127 integrated with the pump impeller 126 and a member (hub) 129 integrally mounted with the turbine runner 128.

The crankshaft (not shown) of the engine 10 is connected to a front cover 127. The input shaft 130 connected to the turbine runner 128 is connected to the overdrive planetary gear mechanism 13
And one carrier 132.

In the planetary gear mechanism 131, a clutch C0 and a one-way clutch F0 are provided between the carrier 132 and the sun gear 133. The one-way clutch F0 is engaged when the sun gear 133 rotates forward relative to the carrier 132 (rotation in the rotation direction of the input shaft 130).

On the other hand, a brake B0 for selectively stopping the rotation of the sun gear 133 is provided. Further, a ring gear 134 which is an output element of the auxiliary transmission section 112 is connected to an intermediate shaft 135 which is an input element of the main transmission section 113.

When the clutch C0 or the one-way clutch F0 is engaged, the auxiliary transmission portion 112
Since the whole of the shaft 31 rotates integrally, the intermediate shaft 135 is rotated.
Rotate at the same speed as the input shaft 130. When the brake B0 is engaged and the rotation of the sun gear 133 is stopped, the ring gear 134 is rotated forward with the speed increased with respect to the input shaft 130. That is, the subtransmission unit 112 can set high-low two-stage switching.

The main transmission section 113 has three sets of planetary gear mechanisms 140, 150, and 160, and these gear mechanisms 140, 150, and 160 are connected as follows.

That is, the sun gear 141 of the first planetary gear mechanism 140 and the sun gear 151 of the second planetary gear mechanism 150 are integrally connected to each other, and the ring gear 143 of the first planetary gear mechanism 140 and the sun gear 151 of the second planetary gear mechanism 150 are connected together. Carrier 1
52 and the carrier 162 of the third planetary gear mechanism 160 are connected. The output shaft 170 is connected to the carrier 162 of the third planetary gear mechanism 160. Further, a ring gear 153 of the second planetary gear mechanism 150 is connected to a sun gear 161 of the third planetary gear mechanism 160.

In the gear train of the main transmission portion 113, one reverse speed and four forward speeds can be set, and a clutch and a brake for this purpose are provided as follows.

That is, the ring gear 153 of the second planetary gear mechanism 150 and the sun gear 161 of the third planetary gear mechanism 160
A clutch C1 is provided between the intermediate shaft 135 and the sun gear 141 of the first planetary gear mechanism 140 and a sun gear 151 of the second planetary gear mechanism 150.

A brake B1 for stopping rotation of the sun gears 141 and 151 of the first planetary gear mechanism 140 and the second planetary gear mechanism 150 is provided. In addition, these sun gears 1
A one-way clutch F1 and a brake B2 are arranged in series between 41, 151 and the casing 171.
The one-way clutch F1 is engaged when the sun gears 141 and 151 try to rotate in the reverse direction (rotation in the direction opposite to the rotation direction of the input shaft 135).

Carrier 142 of first planetary gear mechanism 140
A brake B3 is provided between the motor and the casing 171. Also, the ring gear 16 of the third planetary gear mechanism 160
The brake B4 and the one-way clutch F2 are arranged in parallel between the casing 171 and the brake B4 as elements for stopping the rotation of the motor 3. The one-way clutch F2 is adapted to be engaged when the ring gear 163 attempts to rotate in the reverse direction.

In the automatic transmission 2 described above, the auxiliary transmission portion 112
Can perform high-low two-stage switching, and the main transmission unit 113 can perform four-stage shifting on the forward side, so that a total of one reverse stage and eight forward stages can be performed. it can. FIG. 4 shows an engagement operation table of each clutch and brake for setting these shift speeds. In FIG. 4, a circle indicates an engaged state, a closed circle indicates an engaged state during engine braking, and a blank indicates a released state.

In this embodiment, however, only the first, second, third, fourth and fifth gears are actually used. As is apparent from FIG.
The shift between the speeds is a clutch-to-clutch shift in which the engagement and disengagement of the brakes B2 and B3 must be performed at the same time. In particular, in this shift, if precise learning control is not performed, the specific shift is rather deteriorated. May be.

Next, a control flow for applying the present invention during the clutch-to-clutch shift from the second speed to the third speed will be described with reference to FIG.

This control flow is started when a shift from the second speed to the third speed is determined, and the flag F is set to 1 at the same time.

First, in step 220, various signals,
For example, signals such as Q / N, vehicle speed V, engine cooling water temperature PHW, air-fuel ratio A / F, and the on / off state of the air conditioner are taken in.

At step 230, it is determined whether or not the flag F1 is 1. In this embodiment, the present invention is applied only during the clutch-to-clutch shift from the second speed to the third speed, so "YE
Only when the determination of "S" is made, the process proceeds to step 240 and thereafter.

In step 240, the turbine rotational speed N
It is determined whether or not t is smaller than a value obtained by multiplying the output shaft rotation speed N0 by the gear ratio i2 of the second speed minus a constant N1. This determination is for detecting the start of the inertia phase (shift start) in the shift from the second speed to the third speed, and proceeds to step 250 until the start of the inertia phase is detected. , The flag F2 indicating the start of the inertia phase is reset to 0, and the flow substantially stops.

When it is determined that the inertia phase has started, the flow proceeds to step 260. Step 26
If it is 0, it is determined whether the flag F2 is 1. When it is initially determined that the inertia phase has started, the flag F
Since 2 is 0, a "NO" determination is made here. In step 270, F2 is set to 1 and the count value Cs of the shift start confirmation counter is set to 1.

In step 290, it is determined whether or not the count value Cs of the shift start confirmation counter has reached a predetermined value Csset. Initially, a "NO" determination is made, so the routine proceeds to step 300, where Cs is incremented by one.

In this way, Nt <N
If 0 × i2−N1 is satisfied, the routine proceeds to step 310 on the assumption that the shift from the second speed to the third speed has definitely started. In step 310, it is determined whether or not the change in the auxiliary equipment load is large. That is, when the air conditioner is turned on or off during the gear shift, the change is considered to be large, and the process proceeds to step 350 and thereafter. In step 320, the oxygen sensor 50 determines whether the air-fuel ratio A / F is lean.
The determination is made based on the output from K. If it is determined that the vehicle is in the lean state, the correspondence between the Q / N and the output torque is not clear, and in this case as well, the process proceeds to step 350 and thereafter to prohibit the learning control.

In step 350, the learning control prohibition counter Ct is counted up.

At step 360, it is determined whether or not the learning control prohibition counter Ct has become 4 or more. If it is less than 4, the process proceeds to step 600, where each flag is reset to 0, and the process returns.

That is, the prohibition of the learning control is executed as it is up to three consecutive times.

However, it is not appropriate to prohibit the learning control for a very long time when the number of times reaches four consecutive times, so that the process proceeds to step 370 (only during shifting) to forcibly shift the air-fuel ratio to the rich side. Then, in step 380, the change of the auxiliary equipment load is prohibited (during the shift only), and the process proceeds to step 390 to execute the learning control.

Step 390 and subsequent steps correspond to the learning control flow.

First, at 390, the learning control prohibition counter Ct is reset to zero. In step 400,
It is determined whether the intake air temperature is equal to or higher than a predetermined value. This is because, for example, when estimating the output torque by detecting the intake air amount by the hot tip method, if the intake air temperature is equal to or higher than a predetermined value, the error becomes large, so that the learning control is prohibited.

When the learning control is prohibited due to the intake air temperature being equal to or higher than the predetermined value, the learning control is not counted up by the learning control prohibition counter Ct. This is because the learning control cannot be forcibly performed such as a change in load or a lean or rich state.

In step 410, the value of the flag F3 is determined. This flag F3 is a definite flag for the inertia phase.
Since = 0, the routine proceeds to step 420, where the flag F3 is set to 1, and in step 430, the inertia phase start time (shift start time) Ts is read. In step 440, the output torque ToutS at the start of the inertia phase is estimated from Q / N, PM, and the like.

Once the flag F3 has been set to 1, the flow proceeds to step 450, where it is determined whether the inertia phase has ended (the shift has ended). This judgment is Nt <N0 × i3
This is performed by confirming whether or not + N2 is established. Here, i3 is the gear ratio of the third speed, and N2 is a constant.
If not, the routine proceeds to step 460, where the flag F4 indicating the end of the inertia phase is reset to zero.

When this relationship is finally established, step 4
Proceeding to 70, it is determined whether F4 is 1 or not. F4 at first
Since = 0, the routine proceeds to step 480, where F4 is set to 1, and at the same time, the shift end start counter Ce is set to 1. Once F4 is set to 1, the flow proceeds to step 500 (FIG. 6) from the next time, and it is determined whether the shift end confirmation counter Ce is larger than a predetermined value Ceset.

If this is not the case, the routine proceeds to step 510, where the shift end confirmation counter Ce is counted up. When the number reaches Ceset, it is determined that the shift is surely ended, and at step 520, the inertia phase ends. The time Te is read. In step 530, the output torque ToutE at the end of the inertia phase is estimated by Q / N or PM, and in step 540, the time Tc of the inertia phase is obtained by calculating Te-Ts.

Further, at step 550, | ToutS-T
It is determined whether outE | is smaller than a predetermined value ToutSET. If this relationship is not established, the output torque difference between the start and end of the inertia phase is too large, and it is recognized that it is not appropriate to execute the learning control.
Go to 0.

On the other hand, | ToutS−ToutE | is a predetermined value ToutS
When it is determined that the change is smaller than the ET, it is understood that the change in the engine torque during the shift is small.
Proceeding to 60, average value of engine torque ToutAVE during shifting
Is obtained by 1/2 (| ToutS-ToutE |).

Next, at step 570, the correction coefficient KT is determined according to ToutAVE. This correction coefficient KT is set in advance to an appropriate value by an experiment or the like.

In step 580, the duty ratio Dacc for the solenoid SLN for regulating the back pressure of the accumulator is determined according to the following equation, and the learning control is executed.

Dacc = Dacc + (1−Tc / Tcset) KT

Here, Tcset is a basic target shift time determined in advance when upshifting from the second speed to the third speed.

Since the hardware configuration itself for controlling the back pressure of the accumulator has been widely known as the basis of hydraulic control, a similar configuration may be employed.

At step 590, the shift to the forced rich side is canceled, and the prohibition of the change of the auxiliary equipment load is canceled. At step 600, each flag is reset to "0".

In this embodiment, when the change in the load of the auxiliary equipment during the shift is large, and when the air-fuel ratio A / F
Is lean, the learning control is prohibited up to three times. However, when this prohibition has been performed four times or more, the air-fuel ratio A / F is forcibly shifted to the rich side, and the change in the load of the auxiliary equipment is prohibited during the shift, so that a learning control system is established. Aim. However, it is further determined here whether the intake air temperature is equal to or higher than a predetermined value, and whether the change in engine torque before and after the inertia phase is equal to or higher than a predetermined value. When it is determined that the change in the torque is equal to or more than the predetermined value, the learning control is not performed.

As a result, especially when the air-fuel ratio A / F is in a lean state, the learning control itself is prohibited to prohibit erroneous learning, and when the learning control is executed, the learning control is always performed under a rich state. Since the control is executed, extremely accurate learning can be executed.

If the learning control is not executed, the shift control is executed based on the information of the learning control established immediately before.

In this embodiment, the present invention is applied to the learning of the back pressure control of the accumulator. However, in addition to this, the learning of the line pressure at the time of shifting and the learning of the determination of the shifting timing are widely learned. It can be applied to control in general.

[0081]

As described above, according to the present invention, highly reliable learning control can be executed without erroneous learning regardless of whether the air-fuel ratio is in the lean state or the rich state. An excellent effect of being able to do so is obtained.

[Brief description of the drawings]

FIG. 1 is a block diagram showing the gist of the present invention.

FIG. 2 is a schematic block diagram showing an embodiment of the present invention.

FIG. 3 is a skeleton diagram showing a gear train of the apparatus of the embodiment.

FIG. 4 is a diagram showing an operation state of each friction engagement device of the gear train.

FIG. 5 is a flowchart showing a control flow executed in the apparatus of the embodiment.

FIG. 6 shows a continuation of the control flow of FIG. 5;

[Explanation of symbols]

Reference Signs List 10: engine, 20: engine control computer, 50: various sensor groups, 70: automatic transmission control computer, brakes B2, B3: brakes for clutch-to-clutch shifting between the second and third speeds

Continued on the front page (72) Inventor Masahiro Hayabuchi 10 Takane, Fujii-machi, Anjo, Aichi Prefecture Inside Aisin AW Co., Ltd. (72) Masahiko Ando 10, Takane, Fujii-cho, Anjo, Aichi Aisin A (56) References JP-A-2-57438 (JP, A) JP-A-3-172545 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) F16H 61 / 00-61/24 B60K 41/06-41/10 F02D 41/00

Claims (1)

(57) [Claims] A shift control device for an automatic transmission configured to learn and control the hydraulic pressure supplied to or discharged from a friction engagement device during gear shifting according to the output torque of a prime mover. Means for detecting the shift characteristic of the motor, means for indirectly detecting the output torque of the prime mover based on the load of the prime mover, means for obtaining the target shift characteristic from the output torque of the prime mover detected indirectly, Means for learning control of the hydraulic pressure so as to match the target shift characteristic, and means for maintaining the air-fuel ratio of the prime mover below the stoichiometric air-fuel ratio when the learning control is performed. Transmission control device for transmission.