JPH03249466A - Line pressure controller for automatic transmission - Google Patents

Abstract

PURPOSE:To remarkably improve speed change shock performance by fixing intake air flow for setting line pressure to a detected value at the time of the occurrence of the change of an engine speed for a period from the occurrence of the change of engine speed to the completion during speed change. CONSTITUTION:A detection means (a) detects intake air flow per rotation, a line pressure setting means (b) presumes torque for setting a line pressure, a line pressure control means (c) actuates line pressure actuator for control the line pressure in response to the torque. In this instance, an intake air flow fixing means (f) fixes the intake air flow for setting the line pressure in the line pressure setting means (b) as a detected value upon the occurrence of the change of an engine speed from the occurrence of the change of the engine speed to the completion during speed changing according to the detected results of detection means (d,e). Thus, occurrence of any shock of the speed changing can be restrained.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a line pressure control device for controlling line pressure of an automatic transmission for an automobile.

<Conventional technology> In automatic transmissions for automobiles, the discharge pressure of an oil pump is regulated to obtain line pressure, which is then supplied to a hydraulic circuit to control the operating hydraulic pressure of a torque converter and various speed change elements in a gear type transmission. This line pressure is based on the engine output (
The hydraulic pressure is controlled to the appropriate level according to the torque (torque).

In other words, in an automatic transmission, the line pressure that is the source of the operating oil pressure for the torque converter and various transmission elements must be adjusted to the appropriate oil pressure according to the torque generated by the engine. Although the speed is faster, the torque transmission efficiency is higher and engine vibrations and shift shocks are transmitted to the output shaft, resulting in increased noise and vibration. Additionally, if the oil pressure is lower than the appropriate oil pressure during gear shifting, the gear shifting shock will be small, but slip will occur and the transmission efficiency will be low, resulting in a feeling of prolonged shifting and deteriorating the durability of the automatic transmission. , further worsening fuel efficiency.

Therefore, in the past, the amount of intake air per rotation was calculated from the intake air flow IQ detected based on the signal from the air flow meter and the engine rotation speed N calculated based on the signal from the crank angle sensor. Torque T
Calculate Q = K - Q/N (K is a constant), set the line pressure by referring to a map in which the optimal line pressure has been determined in advance, and drive the line pressure actuator based on this. The line pressure was controlled by
(See Publication No. 054).

<Problems to be Solved by the Invention> However, when considering line pressure control during gear shifting in such a conventional line pressure control device, there is a region where K - Q/N changes significantly during gear shifting, and in such a region, There was a problem in that the line pressure changed significantly during gear shifting, making it impossible to control it well.

In view of these conventional problems, it is an object of the present invention to achieve a significant improvement in shift shock performance by achieving an appropriate ratio of line pressure control during gear shifts.

<Means for Solving the Problems> Therefore, as shown in FIG. 1, the present invention provides an intake air amount detection means (a) for detecting intake air t per unit rotation.
a line pressure setting means (b) for setting the line pressure based on the detected intake air amount; and a line pressure setting means (b) for controlling the line pressure of the automatic transmission by driving a line pressure actuator based on the set line pressure. In a line pressure control device for an automatic transmission comprising a pressure control means (C), the following (d) to
The structure shall include a means for

(d) Gear shift detection means (
e) A rotational change detection means for detecting a change in engine rotational speed. Based on the detection results of the speed change detection means and the rotational change detection means, the line pressure setting means adjusts the speed from the occurrence of a rotational change during gear shifting until the end thereof. Function of the intake air amount fixing means for fixing the intake air amount for line pressure setting to the value detected at the time of rotation change occurrence> In the above configuration, the intake air amount per unit rotation is detected and the torque is estimated; The line pressure is set and controlled based on the
By detecting rotational changes based on changes in gear ratio due to gear shifting, and fixing the intake air amount for line pressure setting to the detected value at the time of rotational change, from the time the rotational change occurs until the end of the rotational change,
Line pressure is substantially identified to prevent shift shock from occurring.

The reason why the intake air amount for setting the line pressure is not fixed at the same time as the shift starts, but is fixed after waiting for the rotational change to occur is to estimate and control the torque based on the latest information until then. be.

<Example> An embodiment of the present invention will be described below.

Referring to FIG. 2, an automatic transmission 2 is provided on the output side of the engine 1. The automatic transmission 2 includes a torque converter 3 interposed on the output side of the engine 1, a gear type transmission 4 connected via this torque converter 3, and this gear type transmission 4.
It is equipped with a hydraulic actuator 5 that connects and releases various speed change elements therein. Although the hydraulic pressure applied to the hydraulic actuator 5 is ON/OFF controlled via various electromagnetic valves, only shift electromagnetic valves 6A and 6B for automatic gear shifting are shown here. Note that 7 is an output shaft of the automatic transmission 2.

Here, the torque converter 3 and the hydraulic actuator 5
An oil pump 8 driven by the input shaft of the gear transmission is used to obtain the line pressure, which is the working oil pressure for the orifice 9, t [valve 10 . A pressure modifier valve 11 and a pressure regulator valve 12 are provided.

The electromagnetic valve 10 is duty-controlled as described below, and obtains a pilot pressure based on the discharge pressure of the oil pump 8 guided through the orifice 9. The pressure modifier valve 11 amplifies the pilot pressure. The pressure regulator valve 12 regulates the discharge pressure from the oil pump 8 to a line pressure proportional to the pilot pressure from the pressure modifier valve 11, and sends it to a hydraulic circuit such as the torque converter 3 and the hydraulic actuator 5.

Signals are input to the control unit 13 from various sensors.

As the various sensors described above, a hot wire type air flow meter 14 is provided in the intake system of the engine 1 to detect the intake air flow rate Q.

Further, a crank angle sensor 15 is provided on the crankshaft of the engine l or a shaft that rotates in synchronization with the crankshaft. The signal from the crank angle sensor 15 is, for example, a pulse signal for each reference crank angle, and the engine speed N is calculated from the period thereof.

Also, the opening degree TVO of the throttle valve 16 of the intake system of the engine 1
A potentiometer-type throttle sensor 17 that detects
is provided.

Further, a vehicle speed sensor 18 is provided which obtains a rotation signal from the output shaft 7 of the automatic transmission 2 and detects the vehicle speed SP.

The control unit 13 has a built-in microcomputer and mainly performs speed change control and line pressure control.

Shift control is performed in accordance with the operation position of the select lever. In particular, when the select lever is in the D range, shift position 1 of 1st to 4th gears is automatically set according to the throttle valve opening TVO and vehicle speed VSP, and the shift is performed. % for magnetic valves 6A and 6B
The combination of N and OFF is controlled to control the gear type transmission 4 to its shift position via the hydraulic actuator 5.

The line pressure control is carried out using the electromagnetic valve 1 as a line pressure actuator according to the line pressure control routine shown in FIG.
0 under duty control. Here, the line pressure can be increased by increasing the duty (valve open time ratio).

Next, the line pressure control routine shown in FIG. 3 will be explained.

Step I ([k is written as Sl. The same applies below)
Now, the intake air flow rate Q detected based on the signal from the air flow meter 14 and the engine speed N calculated based on the signal from the crank angle sensor 15 are read.

In step 2, it is determined whether or not gear shifting is in progress. This determination is made based on the shift flag, which is set when a shift is in progress in the shift control routine.

If the gear is not being shifted, proceed to step 3, and from the intake air flow rate Q and the engine rotation speed N, calculate the torque TQ = K - Q/N as corresponding to the intake air amount per unit rotation.
(K is a constant). Next, proceed to step 4, and refer to a normal map that predetermines the optimal line pressure LP for normal times almost proportionally to the torque TQ, and set the line pressure LP to
Set by search.

Then, the process proceeds to step 8, where a duty corresponding to this line pressure LP is outputted to drive the electromagnetic valve 10, thereby obtaining the optimum line pressure.

If the gear is being changed, steps 5 to 7 are executed to control the line pressure during the gear change, and the process proceeds to step 8.

In step 5, the amount of change ΔN of the engine speed N with respect to the previous value is detected, and it is determined whether or not this is greater than or equal to a predetermined value (presence or absence of a change in rotation).

If there is no rotation change, proceed to step 6, and from the intake air flow rate Q and the engine rotation speed N, calculate the torque TQ = K - Q/N as corresponding to the intake air amount per unit rotation.
Calculate. Next, the process proceeds to step 7, in which the optimal line pressure LP for shifting according to the torque TQ is set by searching for the line pressure LP from the torque TQ by referring to a predetermined shift map. In addition, the shift map shows the type of shift (1st gear →
A plurality of line pressures are provided so that the line pressure can be varied for each shift (2nd speed, 2nd speed → 3rd speed, etc.) or according to the shift transition detected by rotational change.

Then, in step 8, the optimum line pressure is obtained by outputting a duty corresponding to this line pressure LP and driving the electromagnetic valve 10.

If there is a rotational change during the gear shift, the process proceeds from step 5 to step 7.8 without executing step 6.

That is, based on the latest Q, N, the torque TQ- to -Q
/N calculation is not performed. As a result, the torque TQ used for the search in step 7 is the one at the time the rotation change occurs, and the line pressure setting torque TQ is fixed at the value at the time the rotation change occurs from the time the rotation change occurs to the end during gear shifting. , which essentially fixes the line pressure. however,
Since the shift map is selected according to the shift transition detected by the rotational change, the line pressure may change as a result.

Therefore, as shown in FIG. Torque TQ= during gear shifting
Even if K-Q/N changes significantly, the torque is fixed at the torque at the time of the rotational change (broken line in the figure) from the time the rotational change occurs to the end, thereby preventing the occurrence of a shift shock.

Here, the portion of step 1.3.6 corresponds to the intake air amount detection means, the portion of step 4.7 corresponds to the line pressure setting means, and the portion of step 8 corresponds to the line pressure control means. Further, the part in step 2 corresponds to a speed change detection means, the part in step 5 corresponds to a rotation change detection means 17, and the part in which step 6 is not executed based on the determination in step 5 corresponds to an intake air amount fixing means.

Note that the torque TQ = -Q/N estimated from the intake air flow rate Q and the engine rotation speed N is the basic fuel injection amount, which is the basis for calculating the fuel injection amount by the electronically controlled fuel injection device (fuel injector). is equivalent to

<Effects of the Invention> As explained above, according to the present invention, the amount of intake air for setting the line pressure can be fixed at an appropriate value (16) during gear shifting, and the line pressure can be substantially fixed. It is possible to obtain the effect that the shift shifting performance can be significantly improved.

[Brief explanation of drawings]

Fig. 1 is a functional block diagram showing the configuration of the present invention, Fig. 2 is a system diagram showing an embodiment of the invention, Fig. 3 is a flowchart of the line pressure control routine, and Fig. 4 shows characteristics during shifting. It is a diagram. ■... Engine 2... Automatic transmission 8... Oil pump 1.0... NTII valve 11...
・Pressure modifier valve 12...Pressure regulator 13...Control unit
14... Air flow meter 15... Crank angle sensor

Claims (1)

[Scope of Claims] An intake air amount detection means for detecting an intake air amount per unit rotation, a line pressure setting means for setting a line pressure based on the detected intake air amount, and a line pressure setting means for setting a line pressure based on the set line pressure. A line pressure control device for an automatic transmission, comprising a line pressure control means for controlling a line pressure of an automatic transmission by driving a line pressure actuator, comprising: a shift detection means for detecting that a shift is in progress; a rotation change detection means for detecting a change in the speed change; and a rotation change detection means for detecting a change in the speed change from the occurrence of the rotation change during the speed change to the end thereof, based on the detection results of the speed change detection means and the rotation change detection means.
A line pressure control device for an automatic transmission, comprising: an intake air amount fixing means for fixing an intake air amount for setting the line pressure in the line pressure setting means to a value detected when a rotational change occurs.