JP2572291Y2 - Line pressure 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 line pressure control device for controlling a line pressure of an automatic transmission for an automobile.

[0002]

2. Description of the Related Art In an automatic transmission for an automobile, an output of an engine is generally input to a gear type transmission via a torque converter, and in the gear type transmission, various friction elements are selectively operated by a line pressure to perform a predetermined shift. The shift to another shift speed is performed by selecting the speed and changing the operating friction element.

For this reason, the line pressure is preferably a value corresponding to the input torque to the gear transmission, which is preferable for tuning when increasing transmission efficiency or reducing shift shock. However, there is almost no technique for directly detecting the transmission input torque, and the transmission pressure is estimated from other factors, and the line pressure is controlled based on the estimation. For example, Japanese Utility Model Application 1-6994
As described in 6 JP, from the viewpoint of capable of substantially judging the transmission input torque by the intake air amount per unit rotation of the engine, detecting an intake air quantity Q and the engine rotational speed N _E of the engine Thus, the transmission input torque is estimated based on these. That is, based on both detected values, Q /
Calculate _NE and calculate this Q /
N _E and output torque of the torque converter from the engine rotational speed N _E, that is since it is found transmission input torque, and sets the target line pressure by referring to a map based on these values. Then, the line pressure actuator is driven based on the obtained target line pressure to control the line pressure.

[0004]

However, in the torque estimation method based on the amount of intake air of the engine as described in the above-mentioned publication, the air flow using a temperature-sensitive resistor such as a hot wire (hot wire) or a hot film is disclosed. An automobile equipped with a meter has a problem as described below.

When measuring the amount of intake air with this type of air flow meter, a bridge circuit is formed including a temperature-sensitive resistor, and the current supplied to the bridge circuit is set so that the unbalanced voltage of the bridge circuit is always zero. Is detected to detect the amount of intake air. For example, if the intake air amount increases and the temperature sensitive resistor is cooled while the bridge circuit is balanced, the balance of the bridge circuit is lost due to a change in the resistance value. Based on this deviation, the supply current increases, whereby the temperature of the temperature-sensitive resistor rises, the resistance value returns to the original value, and the unbalanced voltage of the bridge circuit returns to zero. That is, the current supplied to the bridge circuit is controlled so that the temperature of the temperature-sensitive resistor is maintained at a constant value. The supply current value at this time corresponds to the intake air amount, and the intake air amount is thereby detected.

Accordingly, in the case of this type of air flow meter, the temperature of the temperature-sensitive resistor is set to a predetermined temperature (corresponding to the resistance value of the temperature-sensitive resistor at which the unbalanced voltage of the bridge circuit becomes zero) from when the power to the bridge circuit is turned on. Until the temperature of the temperature-sensitive resistor is lower, the measured intake air amount is larger than the true intake air amount, and is output.
As shown in (1), the measurement error in this period is large.
FIG. 4 shows the error rate (= Δ) from the time when the ignition switch is turned on for the hot wire air flow meter.
Q / Q) over time, where ΔQ
Is the difference between the detected intake air amount Q _d and the true intake air quantity Q by the air flow meter (ΔQ = Q _d -Q).

As described above, in the air flow meter using the temperature-sensitive resistor, the error in the detected value of the intake air amount is large at the initial stage of turning on the power (the initial stage of turning on the key switch).
In the case of estimating the transmission input torque based on the intake air amount, when a shift operation to the D range or the R range is performed during a period in which the error of the detection value is large at the initial stage of power-on,
There arises a problem that the set line pressure becomes larger than the actual required value and the shift shock becomes large.

The present invention has been made in view of the above circumstances, and aims at optimizing the line pressure at the initial stage of key switch ON in an automobile equipped with an intake air amount detecting means using a temperature-sensitive resistor to reduce a shift shock. It is an object of the present invention to provide a line pressure control device for an automatic transmission that can improve driving performance by relaxing the control.

[0009]

SUMMARY OF THE INVENTION For this reason, the present invention uses FIG.
As shown in the figure, intake air amount detection means for detecting the intake air amount of the engine using a temperature-sensitive resistor, and line pressure setting means for setting a line pressure based at least on the detection value of the intake air amount detection means A line pressure control device for controlling a line pressure of the automatic transmission by driving a line pressure actuator based on the set line pressure. Time measuring means for measuring an elapsed time from the start of energization to the temperature-sensitive resistor; and a line pressure setting operation based on the detected value of the intake air amount detecting means until the time measured by the time measuring means exceeds a preset time. Prohibiting means for prohibiting the opening, throttle valve opening detecting means for detecting an opening of a throttle valve interposed in the intake passage, and a throttle valve for a prohibition period by the prohibiting means. It was constructed and a line pressure setting means for setting the line pressure based on the throttle valve opening detected by the torque valve opening detection means.

[0010]

In such a configuration, normally, torque is estimated from, for example, the engine rotation speed or the like based on the intake air amount detected by the intake air amount detection means, and the line pressure is set and controlled based on the torque. Within a predetermined time after the key switch is turned on, that is, in a period until the temperature of the temperature-sensitive resistor rises sufficiently and the error in the detection value of the intake air amount detecting means becomes sufficiently small, the amount based on the intake air amount By prohibiting the setting of the line pressure and setting the line pressure based on the throttle valve opening detected by the throttle valve opening detecting means,
An appropriate line pressure can be set in the initial stage of turning on the power supply, in which the detection error of the intake air amount detecting means is large, and the occurrence of a shift shock can be prevented.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. In FIG. 2 showing the configuration of the present embodiment, 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 transmission 4 connected via the torque converter 3, and a combination of various transmission elements in the gear transmission 4. A hydraulic actuator 5 for performing a release operation. The operating oil pressure for the hydraulic actuator 5 is ON / OFF controlled through various electromagnetic valves, but here only the shift electromagnetic valves 6A and 6B for automatic shifting are shown.

Here, an oil pump 7 driven by an input shaft of a gear type transmission 4 is used to obtain a line pressure which is an operating oil pressure for the torque converter 3 and the hydraulic actuator 5, and an orifice 8 and an electromagnetic valve are used. 9, a pressure modifier valve 10 and a pressure regulator valve 11 are provided. Electromagnetic valve 9
Is controlled in duty as described later to obtain a pilot pressure based on the discharge pressure of the oil pump 7 guided through the orifice 8. The pressure modifier valve 10 amplifies the pilot pressure. The pressure regulator valve 11 regulates the discharge pressure from the oil pump 7 to a line pressure proportional to the pilot pressure from the pressure modifier valve 10 and sends it to a hydraulic circuit such as the torque converter 3 and the hydraulic actuator 5.

The control unit 12 receives signals from various sensors. The various sensors include an opening degree TV of a throttle valve 13 of an intake system of the engine 1.
A potentiometer type throttle sensor 14 is provided as a throttle valve opening detecting means for detecting O.
Further, a crank angle sensor 15 is provided on the crank shaft of the engine 1 or a shaft that rotates in synchronization with the crank shaft. The signal from the crank angle sensor 15 is a pulse signal of, for example, the reference crank angle each engine rotational speed N _E is calculated from the cycle.

Further, a vehicle speed sensor 16 for detecting a vehicle speed VSP by obtaining a rotation signal from an output shaft of the automatic transmission 2 is provided. Further, a temperature sensitive resistor, for example, an air flow meter 17 as an intake air amount detecting means using a hot wire (hot wire) is provided upstream of the throttle valve 13 in the intake system of the engine 1.

A signal from a key switch 18 is input to the control unit 12. The control unit 12 has a built-in microcomputer and mainly performs shift control and line pressure control. The shift control is performed in accordance with the operation position of the select lever. Particularly, when the select lever is in the D range, the throttle valve opening TVO and the vehicle speed V
Automatically sets shift positions such as 1st to 4th speed according to SP,
By controlling the ON / OFF combination of the shift solenoid valves 6A and 6B, the gear type transmission 4 is controlled via the hydraulic actuator 5.
Is controlled to the shift position.

The line pressure control is performed by duty control of the electromagnetic valve 9 as a line pressure actuator according to the flowchart shown in FIG. Here, the line pressure can be increased by increasing the duty (valve opening time ratio). Next, the line pressure control of this embodiment will be described with reference to the flowchart shown in FIG.
In the present embodiment, the functions of the time measurement unit, the prohibition unit, the line pressure setting unit, and the line pressure control unit are as follows.
The software is provided as shown in the flowchart of FIG.

First, step 1 (in the figure, described as S1;
In the following, a signal from the key switch 18 is input. In step 2, it is determined based on a signal from the key switch 18 whether or not an ignition switch (IGN SW) is ON. If it is not ON, proceed to step 3 and set the flag F = 0. If it is ON, the process proceeds to step 4.

In step 4, the flag F is determined.
When the flag F = 0, the ignition switch is turned off
Then, it is determined that the timer has been turned ON, and the process proceeds to step 5 to start the timer. Thereby, measurement of the time T from the power-on is started. In step 6, it is compared with the set time T ₀ determined in advance and the measurement time T. The set time T
₀ is set to a time when the error rate shown in FIG. 4 is within, for example, 4%. When T ₀ <T, that is, when the measurement time T is within the set time T _0, it is determined that the measurement error of the intake air amount is large, and the line pressure control based on the intake air amount having a large error is performed. Prohibition is made, and the routine proceeds to step 7, where the line pressure control based on the throttle valve opening TVO is executed.

In the line pressure control based on the throttle valve opening TVO, the actual throttle valve opening TVO detected by the throttle sensor 14 is detected by referring to a map in which an optimum line pressure is determined in advance according to the throttle valve opening TVO. , A line pressure is set by searching for a line pressure, a duty corresponding to the set line pressure is calculated, and the calculated duty is output to drive the electromagnetic valve 9 to obtain an optimum line pressure.

At step 8, the flag F = 1 is set. Then, after a lapse of time, in step 6, T ₀ <
T, i.e., when the measured time T exceeds the set time T _0, the flow advances from step 6 to step 9 to stop the line pressure control based on the throttle valve opening TVO so far, the intake air quantity Q
Shifts to line pressure control based on

[0021] The line pressure control based on the intake air amount, the same as in the prior art, on the basis of the intake air amount Q detected by the air flow meter 17, the engine rotational speed N _E detected by the crank angle sensor 15, per unit an intake air quantity Q / N _E is calculated, and sets the line pressure by searching the line pressure from a predetermined map based on the the Q / N _E and N _E. Thereafter, similarly to the line pressure control based on the throttle valve opening TVO, a duty corresponding to the set line pressure is calculated, and the calculated duty is output to drive the electromagnetic valve 9 to obtain an optimum line pressure. .

As described above, in the initial stage of turning on the power where the measurement error of the air flow meter 17 is large, the setting of the line pressure based on the intake air amount is prohibited, and the line pressure is set based on the throttle valve opening TVO. Even if the gearshift operation is performed immediately after the vehicle is turned on, there is no large gearshift shock and the driving performance is good. In the line pressure setting of the present embodiment, the output shaft rotation speed of the transmission or a rotation speed having a proportional relationship with the output shaft rotation speed may be used instead of the engine rotation speed.

[0023]

As described above, according to the present invention, the setting of the line pressure based on the intake air amount is prohibited and the line pressure is set based on the throttle valve opening within a predetermined time from the start of the power supply. As a result, even in vehicles equipped with intake air amount detection means using a temperature-sensitive resistor with a large detection error at the beginning of power-on, it is possible to prevent shift shocks during gear-shift operations at the beginning of power-on and improve drivability. it can.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating the configuration of the present invention.

FIG. 2 is an overall system configuration diagram of an embodiment of the present invention;

FIG. 3 is a flowchart showing a line pressure control routine according to the embodiment;

FIG. 4 is a characteristic diagram when a power supply of a hot wire air flow meter is turned on.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Engine 2 Automatic transmission 3 Torque converter 4 Gear type transmission 9 Solenoid valve 12 Control unit 13 Throttle valve 14 Throttle sensor 15 Crank angle sensor 17 Air flow meter 18 Key switch

Continuation of the front page (56) References JP-A-3-194258 (JP, A) JP-A-3-209049 (JP, A) JP-A-3-84257 (JP, A) JP-A-5-196121 (JP) JP-A-58-66018 (JP, A) JP-A-4-366059 (JP, A) JP-A-3-122249 (JP, U) JP-A-58-1739 (JP, U) (58) Field surveyed (Int. Cl. ⁶ , DB name) F16H 61/00 F02D 41/00 F02D 45/00

Claims (1)

(57) [Scope of request for utility model registration] 1. An intake air amount detecting means for detecting an intake air amount of an engine using a temperature-sensitive resistor, and a line pressure setting means for setting a line pressure based on at least a detection value of the intake air amount detecting means. A line pressure control device for controlling a line pressure of the automatic transmission by driving a line pressure actuator based on the set line pressure. Time measuring means for measuring an elapsed time from the start of energization to the temperature-sensitive resistor; and a line pressure setting operation based on the detected value of the intake air amount detecting means until the time measured by the time measuring means exceeds a preset time. Prohibition means for prohibiting
A throttle valve opening detecting means for detecting an opening of a throttle valve interposed in the intake passage; and a line based on a throttle valve opening detected by the throttle valve opening detecting means during a prohibition period by the prohibiting means. A line pressure control device for an automatic transmission, comprising: line pressure setting means for setting a pressure.