JPH0297763A - Speed change control device for automatic transmission - Google Patents

Abstract

PURPOSE:To prevent generation of an overrun phenomenon by providing a shift pattern changing means which transfers a shift pattern, when a shift up is performed to a specific speed change shift, to a low car speed side, when a maximum engine speed exceeds the target maximum engine speed by a predetermined value or more. CONSTITUTION:When a maximum engine speed, in the time of shift up from 1-speed to 2-speed, exceeds the target maximum engine speed, increasing by a predetermined value or more, a 1 2 shift pattern, as shown by a curve L2, is transferred to a low car speed side from a reference position (curve L1), and a shift up control is early performed from a lower speed side. Consequently, in the time of shift up, generation of an overrun phenomenon of engine speed, such as reaching the permissible engine speed, is surely prevented, and an engine maintains well together its durability, reliability and fuel consumption performance.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a shift control device for an automatic transmission.

(Prior Art) In recent years, there has been a tendency for automatic transmissions consisting of a torque converter and a speed change gear device to be frequently used as transmissions for automobiles. In such an automatic transmission, a desired gear stage can be obtained by selectively engaging or disengaging a plurality of hydraulic friction engagement elements provided in a transmission gear device (for example, a specific gear position). (Refer to Japanese Patent Publication No. 187630/1983).

Shift control in this automatic transmission involves a shift pattern that is predetermined for each gear depending on the throttle valve opening (i.e., engine load) and vehicle speed.
Shifting up from speed to second speed is performed based on the shift pattern shown by line L1 in FIG. Also,
As shown in the diagram Lo in Fig. 4, this shift operation is completed at an engine speed as close as possible to the predetermined target maximum engine speed corresponding to each throttle valve opening. The actuation timing of the fastening element is set. For example, when upshifting from 1st gear to 2nd gear, when the throttle valve is fully opened (i.e., when accelerating suddenly by fully depressing the accelerator pedal),
A shift-up operation is performed at a vehicle speed of V, and the engine speed when the shift-up is completed is approximately EO! Then,
Furthermore, when the throttle valve opening is half-open, a shift-up operation from 1st to 2nd gear is performed at vehicle speed ■1, and the operation timing of each friction engagement element is set so that the engine speed is approximately EOL when the shift-up is completed. has been done.

(Problem to be Solved by the Invention) However, in this automatic transmission, the operating characteristics of each frictional engagement element involved in gear shifting operation are not always constant, and for example, manufacturing errors such as variations in clutch clearance, and dimensions due to aging. Changes vary depending on various factors such as changes in shape and temperature of hydraulic oil (that is, the magnitude of viscous resistance).

In particular, if the operating characteristics of the frictional engagement element change in such a way that the timing of engagement or disengagement is delayed, the upshift operation takes time and the engine rotational speed increases beyond the predetermined target maximum engine rotational speed. death,
For example, during full-throttle acceleration, the engine speed may exceed the allowable engine speed, which is set slightly higher than the target maximum engine speed (i.e., engine speed overrun phenomenon), reducing the durability and reliability of the engine. There is also a concern that problems such as a decrease in engine fuel efficiency may occur due to the prolonged high-speed rotation range.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a shift control device for an automatic transmission that prevents the occurrence of an overrun phenomenon in engine speed during upshifts and maintains driving performance and fuel efficiency. .

(Means for Solving the Problem) The present invention, as a means for solving the problem,
In an automatic transmission that performs gear change control according to a predetermined shift pattern corresponding to vehicle speed and engine load, the maximum engine speed at the time of upshifting to a specific gear and the engine load at the time of said upshifting are determined. A shift pattern for upshifting to the specific gear position is determined when the maximum engine speed exceeds the target maximum engine speed by a predetermined value or more by comparing the target maximum engine speed correspondingly with a predetermined target maximum engine speed. The present invention is characterized by comprising a shift pattern changing means for shifting the vehicle speed to a lower vehicle speed side.

(Function) With this configuration of the present invention, when the maximum engine speed during upshifting exceeds the target maximum engine speed in that case and increases by a predetermined value or more, the shift line is shifted to the low vehicle speed side. The next upshift operation will be started from a lower rotational speed than the previous one.

(Effects of the Invention) Therefore, according to the automatic transmission shift control device of the present invention,
The shift pattern is constantly changed and controlled so that the maximum engine speed during upshifts does not exceed the target maximum engine speed by more than a predetermined value, so the engine speed reaches the allowable engine speed during upshifts. It is possible to reliably prevent the occurrence of a rotational speed overrun phenomenon, and to maintain good durability, reliability, and fuel efficiency of Ennon.

(Embodiments) Hereinafter, preferred embodiments of the present invention will be described with reference to FIGS. 1 to 4.

FIG. 1 shows an automobile power unit equipped with a transmission control device according to an embodiment of the present invention, in which reference numeral 1 denotes an engine, and 2 denotes an automatic transmission consisting of a torque converter 3 and a transmission gear device 4. It is a machine. The speed change gear device 4 is equipped with three speed change solenoids 5, 5.5 and one lockup solenoid 6, and each speed change solenoid 5 can be selectively controlled by a control signal from a controller 7. The desired transmission can be obtained by turning ON and OFF. The controller 7 also includes an engine rotation speed sensor 1 as a shift control factor.
1, a signal corresponding to the engine speed is input from the throttle valve opening sensor 12, a signal corresponding to the throttle valve opening, that is, an engine load, and a signal corresponding to the vehicle speed from the vehicle speed sensor 13. Based on these input signals, the controller 7 selects a gear position from a shift map (see FIG. 3), and activates each of the above-mentioned shift solenoids 5.
5.5 to obtain a predetermined gear.

In this embodiment, the present invention is applied to prevent the occurrence of a malfunction caused by a delay in the engagement or release operation of each friction engagement element of the transmission gear device 4 when shifting up from 1st gear to 2nd gear. This is prevented by shifting the shift pattern. That is, from l speed to 2
When the maximum engine speed at that time exceeds the target maximum engine speed (see FIG. 4) and increases by a predetermined value or more during a shift-up to a higher speed, the line diagram in FIG. 3 is shown.

As shown in , the 1-2 shift pattern is shifted to a lower vehicle speed side than the reference position (diagram), and the upshift operation is performed earlier from the lower rotation side, and conversely, the maximum engine rotation speed during soft-up is changed. is lower than the target maximum engine rotation speed by a predetermined value or more, the l → 2 shift pattern is shifted to a higher vehicle speed side than the reference position as shown by line L3 in Fig. 3, and the upshift operation is performed at a higher rotation speed. (Although the content of the present invention is to shift the shift pattern to the low vehicle speed side, in this embodiment, shifting the shift pattern to the high vehicle speed side is added to this. (This makes the effects of the present invention even more effective.)

Shift control that involves this shift pattern shift will be described below with reference to the flowchart shown in FIG. 2.

After starting the control, first check the current throttle valve opening TV.
In addition to reading O, engine rotation speed Ne, and vehicle speed ■ from the corresponding sensor outputs, the target maximum engine speed at the time of shifting from l to 2 corresponding to the current throttle valve opening is determined from the target maximum engine rotation speed map (see Figure 4). Rotation speed Eo
Find (step Sυ.

Next, based on the shift map (see FIG. 3), the l→2 shift timing is determined based on the throttle valve opening 'r vo and the vehicle speed V (step SZ). Then, at the 1-2 shift timing, each of the above-mentioned shift solenoids 5 and 5
．． 5 to perform an upshift operation from 1st gear to 2nd gear (step S3).

Next, read the maximum engine speed EIIlaX during the 1-2 gear shift just executed (step S), compare this maximum engine speed E maw with the target maximum engine speed Eo, and compare the current 1-2 speed change with the target maximum engine speed Eo. It is determined whether or not it is necessary to shift the shift pattern, and if so, it is determined whether the shift pattern should be shifted toward a higher vehicle speed or a lower vehicle speed. That is, the maximum enon rotation speed EIIl
When a is greater than the target maximum engine speed Eo by a predetermined value a or more (that is, when the engine speed is likely to reach the allowable engine speed), the shift line is shifted to the current position as shown in Fig. 3. The vehicle speed is shifted from the position (diagram, ) to the low vehicle speed side (diagram, ) (step Sa). By doing this, the next l → 2 shift up will start from a lower vehicle speed side than the previous one, that is, from a lower engine speed side, so the maximum engine speed at the time of soft up will be the allowable engine speed. This is something that can be reliably prevented from reaching the target.

On the other hand, when the maximum engine speed E maX is smaller than the target maximum engine speed Eo by a predetermined value a or more (that is, the upshift is performed at a considerably lower speed than the target maximum engine speed, and as a result, acceleration performance is impaired). Shift line to a higher vehicle speed than the current one (when the vehicle speed is high).
line diagram L3) (step S,). By doing this, the l→2 shift up is performed at a position as close to the target maximum engine speed as possible, and acceleration performance is improved accordingly.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of an automobile power train equipped with a shift control device for an automatic transmission according to an embodiment of the present invention, FIG. 2 is a control flowchart of the automatic transmission shown in FIG. 1, and FIG. is a shift pattern diagram, and FIG. 4 is a correlation diagram between the throttle valve opening during upshifting and the target maximum engine speed. l・・・・Engine 2 ・ ・ ・ ・ 3 ・ ・ ・ 4 ・ ・ ・ 5 ・ ・ ・ 6 ・ ・ ・ 7 ・ ・ ・ ・ l 1 ・ ・ ・ l 2 ・ ・ ・ l 3 ・ ・・ ・Automatic transmission・torque converter・speed change gear device・speed change solenoid・lockup solenoid・controller・engine speed sensor・throttle valve opening sensor・vehicle speed sensor Gear device: 2 solenoid for gear shift 2 solenoid for lock-up 2 Controller: Engine speed sensor: Throttle valve opening sensor: Vehicle speed sensor 3112 Figure Target maximum engine speed (Eo) No. 41a

Claims (1)

[Claims] 1. In an automatic transmission that performs gear shift control according to a predetermined shift pattern corresponding to vehicle speed and engine load, the maximum engine speed at the time of upshifting to a specific gear and each engine load at the time of said upshifting are determined. A predetermined target maximum engine speed is compared with the target maximum engine speed, and when the maximum engine speed exceeds the target maximum engine speed by a predetermined value or more, the shift to the specific gear is performed. A shift control device for an automatic transmission, comprising a shift pattern changing means for shifting the pattern to a lower vehicle speed side.