JPH0613908B2 - Shift control device for automatic transmission - Google Patents

Description

Detailed Description of the Invention

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shift control device for an automatic transmission, and more particularly to a first transmission capable of automatically switching a plurality of shift speeds and the first transmission.
A second transmission having a gear with a gear ratio difference smaller than the gear ratio difference between the gears of the transmission;
The present invention relates to an improvement of a shift control device for an automatic transmission that achieves a specific shift by simultaneously shifting the transmission and the transmission.

[Prior art]

With the rapid spread of automatic transmissions for vehicles in recent years, the first transmission that can automatically change the gear stage mainly in relation to the vehicle speed and throttle opening etc. is intended to improve fuel efficiency. A so-called overdrive device having a value of 1 or less is often used as a second transmission, which is attached in series. Also, paying attention to the function of the second transmission that can switch between the low speed stage and the high speed stage like this overdrive device, and positively synchronizing this with the shift of the first transmission, the gear between the relatively large speed stages is changed. Shifting the first transmission having a ratio difference and the second transmission having a relatively small inter-gear gear ratio difference at the same time or alternately to perform the shift control as shown in part A of FIG. 3 for example. Therefore, there has already been known a device which achieves a multistage shift of six forward gears (for example, Japanese Patent Laid-Open No. 57-37140). In this way, by arranging the second transmission that can switch between the low speed side and the high speed side with respect to the first transmission in series, the existing automatic transmission is used as a basis and the design change is reduced. While being advantageous in manufacturing, it is possible to easily realize a multistage shift, and to obtain many advantages such as improved fuel economy, improved power performance, and reduction of the burden on the friction material due to the multiple shift stages.

[Problems to be Solved by the Invention]

However, in the case of an automatic transmission in which such a first transmission and a second transmission are simultaneously or alternately changed to achieve a multi-speed shift, for example, from the second speed shown in FIG. Upshift to 3rd gear, 4th gear to 5th gear
In some cases, such as an upshift to a speed stage or a reverse downshift thereof, a new gear stage is achieved by shifting the first transmission and the second transmission in opposite directions. At this time, if each shift is controlled individually, not only is it possible to avoid an increase in shift shock, but the shift may start from a downshift even though it is an upshift, or an upshift after a downshift or a shift after an upshift. There was a problem that a strange driving sensation such as downshifting may occur. In view of such problems, the applicant previously filed Japanese Patent Application No. 59-2.
It has been disclosed in 19454 to 5454 that when the shift of the second transmission is configured to be started and completed during the shift period of the first transmission (hereinafter referred to as the inertia phase), good shift characteristics can be obtained. That is, the gear shift start of the second transmission must not precede the gear shift start of the first transmission, and the gear shift completion of the second transmission must not occur after the gear shift completion of the first transmission. This is the disclosure. However, after that, if the shift completion of the second transmission is completed earlier than the shift completion of the first transmission, the output shaft torque suddenly rises in the inertia phase remaining portion of the first transmission, which causes a problem that the shift shock increases. Was found. Further, it is extremely difficult to match the delicate start and end timings with the intended timing simply by controlling the shift timings of both by a timer or the hydraulic pressure level of the friction engagement device. The problem that there is also emerged. That is,
Due to variations in parts of the automatic transmission, variations in usage conditions, etc., the shift start time, shift time, etc. of each part delicately fluctuates, and errors in shift control timing due to these fluctuations cannot be ignored. . Therefore, in view of such a problem, the present applicant has further made the first
The upshift is always set to a high level by starting the shift of the second transmission after starting the shift of the transmission, and by terminating the shift of the second transmission in synchronization with the end of the shift of the first transmission. It is possible to always start a downshift from a gearshift to a low gearshift, and to obtain good shifting characteristics without the strange driving feeling of upshift after downshift or downshift after upshift. We have developed a technology that enables this (Japanese Patent Application No. 60-144340). At the same time, in this Japanese Patent Application No. 60-144340, in performing the above-mentioned control, based on the result of the shift timing at this time,
A technique has also been disclosed in which the shift control of the second transmission is corrected next time so that the optimum shift characteristic can always be obtained in each vehicle regardless of various variations.

[Problems to be Solved by the Invention]

However, even if such a so-called learning control is performed, if the difference in oil temperature of the automatic transmission between the current shift and the next shift is large, the shift completion of the first transmission and the second shift are completed. It will be difficult to synchronize the completion of gear shifting of the machine. That is, for example, when the oil temperature of the automatic transmission is high, the oil pressure of the friction engagement device leaks in a larger amount in the oil passage of the hydraulic circuit than when the oil temperature of the automatic transmission is low. When it is supplied, it takes time from the start of the hydraulic pressure supply to the start of the shift of the transmission by the supply. On the contrary, when the hydraulic pressure is drained from the friction engagement device, the time from the drain start to the shift start of the transmission by the drain is shortened. Further, when the oil temperature is extremely low (for example, 0 ° C. or lower), the viscous resistance of the oil becomes large, so that it takes time until the hydraulic pressure of the friction engagement device is supplied. In gear shifting in an automatic transmission, a considerable amount of time may elapse between the current gear shift and the next gear shift. Therefore, for example, if the shift control timing is corrected according to the state when the oil temperature is low by several shifts before warming up, and then warming up proceeds without shifting for a considerably long time, When the next shift is performed, the shift completion of the first and second transmissions is not synchronized, and a large shift shock will occur. In this way, the influence is exerted when the oil passage configurations of the first transmission and the second transmission, especially when the oil passages have different lengths, or when the hydraulic pressure supply and the drainage are reversed between the first transmission and the second transmission. When the gears are on, the timing of starting and ending the shift of both transmissions is greatly affected.

[Object of the Invention]

Even in such a case, the present invention determines the timing of the shift start in consideration of at least the oil temperature, and ends the first transmission and the second transmission in exact synchronization. It is an object of the present invention to provide a shift control method for an automatic transmission that enables the above.

[Means for Solving the Problems]

The present invention includes a first transmission that can automatically switch between a plurality of gears and a second transmission that has a gear with a gear ratio difference smaller than the gear ratio difference between the gears of the first transmission, The first
In a shift control device for an automatic transmission, which achieves a specific shift by simultaneously shifting the transmission and the second transmission, as shown in the outline of FIG. A means for starting the shift of the second transmission after the start, a means for ending the shift of the second transmission in synchronization with the end of the shift of the first transmission, a means for detecting an oil temperature, A means for changing the shift start of the second transmission depending on the oil temperature; a means for detecting a shift completion of the shift between the first transmission and the second transmission;
The above object is achieved by including a means for correcting the shift control of the second transmission next time.

[Action]

In the present invention, at least the oil temperature of the automatic transmission is taken into consideration in the correction of the learning control, so that regardless of the warm-up state of the engine, a good and appropriate correction can always be performed. The shift completion of the first and second transmissions can be accurately synchronized. In a preferred embodiment, the correction degree of the shift control is changed according to at least one of the engine load, the vehicle speed, and the type of shift, in addition to the oil temperature of the automatic transmission. As a result, the shift control can be corrected more appropriately, the effect is great, and the hunting can be prevented. Further, it is preferable that the shift control be corrected within a predetermined guard range. As a result, it is possible to prevent the correction from being unduly large for some reason.

【Example】

Embodiments of the present invention will be described in detail below with reference to the drawings. When a new shift speed is achieved by simultaneously shifting the first transmission 60 and the second transmission 40, especially when both transmissions 40, 60 are shifted in opposite directions. As is clear from FIG. 3, when a new shift speed is achieved, there is a shift between the second speed and the third speed, or a shift between the fourth speed and the fifth speed. However, since the purpose is the same, here, the first transmission shifts to a high gear and the second transmission shifts to a low gear, so that the automatic transmission as a whole undergoes an upshift from a second speed to a third speed.
This will be explained by taking an example of shifting to a higher speed. First, FIG. 2 shows an overall outline of an automatic transmission for a vehicle to which this embodiment is applied. This automatic transmission includes a torque converter 20 as its transmission portion, a second transmission 40, three forward gears,
And a first transmission 60 having one reverse speed. The torque converter 20 includes a pump 21 and a turbine 2.
2, a stator 23, and a lockup clutch 24. The pump 21 is connected to the crankshaft 10 of the engine 1, and the turbine 22 is connected to the carrier 41 of the planetary gear unit in the second transmission 40. In the second transmission 40, the planetary pinion 42 rotatably supported by the carrier 41 meshes with the sun gear 43 and the ring gear 44. A clutch C ₀ and a one-way clutch F ₀ are provided between the sun gear 43 and the carrier 41.
A brake B ₀ is provided between the housing and the housing Hu. The first transmission 60 is provided with two rows of front and rear sides as a planetary gear device. This planetary gear device has a common sun gear 61, ring gear 62,
63, planetary pinions 64, 65, and carrier 6
It consists of 6, 67. The ring gear 44 of the second transmission 40 is connected to the ring gear 62 via the clutch C ₁ . A clutch C ₂ is provided between the ring gear 44 and the sun gear 61. Further, the carrier 66 is connected to the ring gear 63, and the carrier 66 and the ring gear 63 are connected to the output shaft 70. on the other hand,
A brake B ₃ and a one-way clutch F ₂ are provided between the carrier 67 and the housing Hu.
A brake B ₂ is provided between the sun gear 61 and the housing Hu via the one-way clutch F ₁ , and a brake B ₁ is provided between the sun gear 61 and the housing Hu. This automatic transmission is provided with the transmission section as described above, and inputs signals from the throttle sensor 100 for detecting the throttle opening that reflects the load state of the engine 1 and the vehicle speed sensor 102 for detecting the vehicle speed. been Yotsute to a central processing unit (ECU) 104, slave connexion hydraulic control circuit electromagnetic solenoid 106 valve _S 1 to S _4, and _{S L} are driven and controlled to a preset speed pattern, the third
As shown in the part B of the figure, shift control is performed by combining the clutches, brakes and the like. Further, in FIG. 3, the mark ◯ indicates the engaged state, and the mark x indicates the engaged state only when the engine brake is used. As shown in FIG. 5, the electromagnetic solenoid valves S ₁ and S ₂ control the first and second shift valves of the first transmission 60, and the electromagnetic solenoid valve S ₃ controls the second shift valve.
The third shift valve that switches between the high speed side and the low speed side of the transmission 40 is controlled, the electromagnetic solenoid valve S ₄ controls a release control valve (described later), and
The electromagnetic solenoid valve S _L is a torque converter 20.
Each of the lockup clutches 24 is controlled. In FIG. 2, reference numeral 110 is a shift position sensor for detecting the positions of N, D, R, etc. operated by the driver, and 112 is a pattern select switch for E (economical traveling), P. (Power running) or the like is selected, 114 is a water temperature sensor for detecting the cooling water temperature of the engine, 116 is a foot brake, and 118 is a foot brake.
Indicate brake switches for detecting the operation of the side brakes. Here, in this embodiment, the central processing unit 10
4, in addition to these input signals, the signal of the oil temperature sensor 120 for detecting the oil temperature of the automatic transmission, and the clutch C ₀
The signal from the rotation speed sensor 122 for detecting the rotation speed of is also input. FIG. 4 shows a main part of the hydraulic control circuit 106. In the figure, reference numeral 200 is a first shift valve for switching the first transmission 60 between the first speed state and the second speed state, and S ₁ is an electromagnetic solenoid for controlling the switching of the first shift valve. A valve, 300 is a third shift valve for switching the high speed side and the low speed side of the second transmission 40, and S ₃
Is an electromagnetic solenoid valve for controlling switching of the third shift valve 300, and 400, 500 and 600 control transient characteristics of hydraulic pressure in an oil passage to the brakes B ₂ , B ₀ and clutch C ₀ , respectively. A reference numeral 700 denotes a manual valve associated with a shift lever operated by a driver.
Since the configuration and operation of each of these devices are basically the same as those of the conventional device, detailed description of each device is omitted. Reference numeral 800 is a release control valve for controlling the time and operating pressure when the action of the brake B ₀ is released by controlling the drain hydraulic pressure of the third shift valve 300. The release control valve 800 has different face areas A ₁ , A ₂ (A ₁
Two lands 802 and 804 of <A ₂ ) are provided, and the drain hydraulic pressure of the brake B ₀ is input to a port 806 provided at an intermediate position between the two lands 802 and 804. A slot pressure from a slot valve (not shown) is applied to the lower port 810 in the figure. This release control valve 80
Zero can be controlled by an electromagnetic solenoid valve S ₄ controlled by the ECU 104. Next, the operation of this embodiment will be described with reference to the flowchart of FIG. First, the flag T is set to zero. When the shift determination is made in step 900 based on the shift point determined by the vehicle speed and the throttle opening, steps 902 and 904 are performed.
At, the oil temperature and throttle opening of the automatic transmission are monitored. After that, the routine proceeds to step 906, where the first transmission 60
Shift command (B ₂ hydraulic pressure supply command, that is, ON command of electromagnetic solenoid valve S ₁ for switching the first shift valve 200) is issued, and B ₂ hydraulic pressure is supplied. Next, at step 908, T _D (T _D is, for example, as shown in FIG. 7) from the shift command of the first transmission 60 so that the low gear shift of the second transmission 40 starts in the inertia phase of the first transmission 60. As shown, after the time of the oil temperature, the throttle opening, and the constant determined depending on the type of gear shift is set, in step 910, the gear shift start command (B ₀ drain command) of the second transmission 4 is set. That is, O of the electromagnetic solenoid valve S ₃ for switching the third shift valve 300
(N command) is issued, and drainage of the B ₀ hydraulic pressure is started. Note that this T _D is an initial value in the throttle opening and the type of shift (in the example of FIG. 7, only the case of power-on upshift from the second speed to the third speed is shown),
From the next shift, only t _D is increased / decreased in the learning flow described later. Then, the rotational speed N _C0 of _{C 0} drum member at step 912, the synchronous speed N _C0 'of _{C 0} drum member is calculated from the output shaft speed _{N o} of the time (= (1+
ρ) × N ₀ ; ρ is a gear ratio). Then at step 914 _{B 2} at _{T 4} hours passed the step 916 from the supply command issued _{B 0} Kuitsukudoren command, terminates the comparison of the _{N C0} and N _C0 'at step 918. Here, T ₄ is the time from the B ₂ supply command in this shift to the completion of the shift of the first transmission, for example, the 7th
As shown in the figure, it is set according to the oil temperature, the throttle opening, and the type of shift. An upper limit value and a lower limit value are set for this T ₄ and the above-mentioned T _D , so that an inappropriate time is not selected due to a malfunction of the sensor system. To explain with reference to FIG. 4 the effect of the far, when the hydraulic pressure of the brake B ₀ is drained, since is pressed the rate of return of Yotsute accumulator 500 to act as of a checking valve orifice 502, the brake B ₀ Drain hydraulic pressure P _B0
Is a predetermined pressure P _B0 ′ determined by the slot pressure applied to the port 810 and the force of the spring 812,
As shown in the left side of FIG. 4, the ports 806 and 808 are short-circuited to rapidly drain the hydraulic pressure of the brake B ₀ , and
When the hydraulic pressure of the brake B ₀ becomes equal to or lower than the predetermined pressure P _B0 ′, the state on the right side of the figure is reached and the port 808 is closed.
The characteristics may be such that the drainage is done smoothly through the orifice 814. As a result, the second transmission can start shifting accurately at any throttle opening, and the release force of the second transmission can be maintained at a predetermined value, so that the second transmission is instantaneously operated. It is possible to avoid a decrease in output torque due to a neutral state. When the B ₀ quick drain command is issued in step 918, the electromagnetic solenoid valve S ₄ is turned off, and the ports 806 and 808 are forcibly short-circuited and the B ₀ hydraulic pressure is quickly drained. At the completion of gear shifting of the first transmission 60 (elapse of T ₄ ), it is the second transmission 40 that causes B ₀ to be quickly drained.
If the completion of the gear shift of the first transmission 60 is later than the completion of the gear shift of the first transmission 60, the second transmission is quickly completed, and the first transmission 60 and the second transmission 40 are This is because the output shaft torque drops due to the drag of the brake B ₀ if the B ₀ oil pressure remains to some extent even after the completion of the shift change. The learning correction flow starts from step 920. First,
In step 920, it is judged whether or not the throttle opening θ during gear shifting is constant, and if so, the routine proceeds to 922, where N _C0 and N _C0 ′ are compared. In this way, limiting the shift that is the basis of the learning control to the shift in which the throttle opening θ is constant is that the next shift is inappropriately corrected based on the result of the shift performed under the special condition. This is to prevent it from happening. When N _C0 > N _C0 ′ is established, it is considered that the gear shifting of the second transmission is completed earlier than the gear shifting of the first transmission is completed. Therefore, the control proceeds to step 924 to synchronize the gear shifting completion with T _D = T _D + t _D (t _D is as shown in FIG.
The shift start of the second transmission is delayed as a constant determined according to the throttle opening and the type of shift. Also 92
At 6, the value of T ₄ is corrected in accordance with the actual completion of the first shift. Whether or not the gear shift of the first transmission is completed can be determined by whether or not the C ₀ drum member rotation speed N _C0 has reached the synchronous shaft rotation speed N _C0 ′. When the second transmission 40 completes the shift earlier than the first transmission 60, the C ₀ drum member rotation speed N _C0 exceeds the 1-degree synchronous rotation speed. 1 The shift of the transmission 60 is completed. If N _C0 > N _C0 'does not hold in step 922, it means that the completion of the shift of the second transmission is later than that of the completion of the shift of the first transmission, or if the completion of the shift is synchronized with step 928.
Advancing the shift start of _{T D = T} D -t D as a second transmission in. It should be noted that this is for substantially stopping the flow until the respective conditions are satisfied at steps 904 and 912 related to the flag T of steps 800 to 803. According to this embodiment, the shift timing of the second transmission of the first transmission can be controlled satisfactorily as shown by the broken line in FIG. 8 with a simple structure, and a sudden change in the output torque can be prevented. Is possible. In the above embodiment, only the result of the shift timing, had as made by a detection of the rotation speed of the C ₀ drum member, means for determining a result of the shift timing in the present invention, or a method Instead of this, for example, the change in the engine rotation speed or the change in the hydraulic pressure supplied to the friction engagement device may be detected. Further, in the above-described embodiment, the correction degree of T _D , T _4, etc. is set according to the engine temperature (slottle opening) and the type of gear shift in addition to the oil temperature. However, the vehicle speed factor may be considered instead of or in addition to these factors. Further, in the above embodiment, the oil temperature sensor 120 directly detects the oil temperature of the automatic transmission.
In the present invention, the method for detecting the oil temperature of the automatic transmission is not limited, and in terms of cost or accommodation space, for example, a signal from the engine cooling water temperature sensor 114 is used as a representative of the oil temperature of the automatic transmission. It may be adopted.

【The invention's effect】

As described above, according to the present invention, the first transmission and the second transmission
Even when a new gear is achieved as a result of shifting the transmission in the opposite directions, for example, the upshift and downshift feelings can be maintained well regardless of the engine warm-up state. It is possible to prevent a strange driving sensation such as downshift after upshift or upshift after downshift from occurring.
Also, as a result of optimal control being performed appropriately for each vehicle,
It is also possible to obtain an excellent effect that it is possible to keep the gear shift shock extremely low.

[Brief description of drawings]

FIG. 1 is a flow chart showing the outline of the contents executed in a shift control device according to the present invention, FIG. 2 is an overall skeleton diagram of an automatic transmission for a vehicle to which the present invention is applied, and FIG. Diagram showing the operating state of each friction engagement device in the automatic transmission, FIG. 4 is a circuit diagram showing a part of the hydraulic control circuit, and FIG. 5 is an electromagnetic solenoid valve and shift in the hydraulic control circuit. FIG. 6 is a block diagram showing the relationship between the valves and the like, FIG. 6 is a flow chart showing the control flow in the apparatus of the above embodiment, and FIG. 7 is a power-on upshift from the second gear to the third gear. FIG. 8 is a diagram showing an example of a map with respect to the throttle opening of T _D , t _D , and T ₄ , and FIG. 8 is a gear shift characteristic diagram showing a comparison between a case where the shift timing is synchronized and a case where the shift timing is not synchronized. B _{0, B 2} ...... brakes, _{C 0} ...... clutch, _S 1 to S ₄ ...... solenoid valves, 40 ...... second transmission, 60 ...... first transmission, 120 ...... oil temperature sensor, 200 ...... 1st shift valve, 300 ...... 3rd shift valve, 400, 500, 600 ... Akyumulator, 502 ... Orifice with check valve, 800 ... Release control valve, 814 ... Orifice.

Claims (3)

[Claims] 1. A first transmission capable of automatically switching between a plurality of gears and a second transmission having a gear having a gear ratio difference smaller than a gear ratio difference between the gears of the first transmission. A shift control device for an automatic transmission that achieves a specific shift by shifting the first transmission and the second transmission at the same time. 2 means for starting the shift of the transmission, means for terminating the shift of the second transmission in synchronization with the end of the shift of the first transmission, means for detecting the oil temperature, and shifting of the second transmission A means for changing the start depending on the oil temperature; a means for detecting a shift completion difference between the first transmission and the second transmission; and a next shift transmission for the second transmission based on the detection result of the shift. A gear shift control for an automatic transmission, characterized by comprising: Apparatus. 2. The correction degree of the shift control of the second transmission is
The shift control device for an automatic transmission according to claim 1, wherein the shift is changed according to at least one of an engine load, a vehicle speed, and a type of shift, in addition to the oil temperature of the automatic transmission. 3. The shift control device for an automatic transmission according to claim 1 or 2, wherein the shift control is corrected within a predetermined guard range.