JPH05118416A - Line pressure controller for automatic transmission - Google Patents

Abstract

PURPOSE:To improve the speed change shock characteristic by securing the optimum line pressure by applying the correction based on the engine warming situation to the suction air quantity as the parameter used for the line pressure control of an automatic transmission. CONSTITUTION:Each signal NE, V, TH, Q, TE is inputted from sensors 6-9 and 50 into a speed change control computer (ATCU) 14 which controls the line pressure for the speed change gear mechanism 1 of an automatic transmission 2 through a control valve 15. The ATCU 14 executes a prescribed control program on the basis of the input signals, and the correction based on the number of engine revolution and the engine water temperature is applied onto the sensor detection value Q of a suction air quantity, and the variation portion due to the engine friction of the engine intake air quantity is canceled.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention corrects the engine intake air amount, which is one of the parameters used for line pressure control, according to the engine temperature and engine speed to improve the shift shock characteristic. The present invention also relates to a line pressure control device for an automatic transmission.

[0002]

2. Description of the Related Art In an automatic transmission, various friction elements are selectively actuated by line pressure to select a predetermined gear stage, and the friction element to be actuated is changed to shift gears to other gear stages. At this time, it is preferable to set the line pressure to a value corresponding to the input torque to the automatic transmission in order to reduce shift shock. For this reason, the applicant of the present application previously found that
As described in Japanese Patent No. 6, a technique has been proposed in which the target line pressure is set based on the engine speed and the engine intake air amount. In this conventional example, the fact that the transmission input torque is substantially proportional to (engine intake air amount) / (engine speed) is used, so the line pressure should be adjusted to obtain the target line pressure obtained. Thus, the line pressure can be appropriately adjusted over almost the entire engine operating condition to reduce the shift shock.

[0003]

Generally, since the engine intake air amount fluctuates so as to increase as the engine friction increases, in order to use the engine intake air amount as a parameter of the line pressure control, the engine intake air amount increases. It is necessary to make a correction to cancel the minute.
At that time, since the engine friction depends on the engine speed and the engine temperature (engine cooling oil temperature: engine water temperature), the engine intake air amount increases as shown in Figs. 9 (a) and 9 (b). As the engine water temperature increases, it changes so as to decrease. However, in the above-mentioned conventional example, since such a variation in the intake air amount of the engine is not corrected, an appropriate line pressure is not always obtained depending on the engine temperature state (cooling or warming up), and a gear shift shock is large during cooling. There was a chance

It is an object of the present invention to solve the above-mentioned problem by adding a correction to the detected engine intake air amount to cancel the variation of the engine intake air amount due to the engine water temperature.

[0005]

To this end, a line pressure control device for an automatic transmission according to the present invention detects an engine intake air amount detected by an intake air amount detecting means and an engine rotation detection as shown in the concept of FIG. The target setting means sets the target line pressure based on the engine speed detected by the means, and the line pressure adjusting means adjusts the line pressure of the automatic transmission so that the target line pressure is achieved. The line pressure control device is provided with an engine warm-up state detecting means for detecting a warm-up state of the engine and an intake air amount correcting means for correcting the engine intake air amount based on the detection result of the warm-up state detecting means. It is what

[0006]

According to the present invention, the line pressure is set so as to achieve the target line pressure set by the target setting means on the basis of the engine intake air amount detected by the intake air amount detecting means and the engine speed detected by the engine rotation detecting means. While the adjusting means adjusts the line pressure of the automatic transmission, the engine intake air amount is corrected according to the engine warm-up state detected by the engine warm-up state detecting means.

[0007] By making this correction, for example, canceling the fluctuation of the engine intake air amount depending on the engine water temperature, the line pressure is changed to the transmission input torque regardless of the temperature condition of the engine. Can be controlled to an appropriate value in accordance with the above, and the shift shock characteristic of the automatic transmission can be improved both during cold and warm up.

[0008]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 2 shows a power train control system of an automobile incorporating a line pressure control device for an automatic transmission according to the present invention.
Is an electronically controlled fuel injection engine, 2 is an automatic transmission, 3 is a differential gear, and 4 is a drive wheel. The engine 1 includes an engine control computer 5, which includes a signal from a vehicle speed sensor 7 that detects an engine speed N _E , a signal from a throttle sensor 8 that detects an engine throttle opening TH, and an engine intake air amount. Q
A signal from the intake air amount sensor 9 for detecting the engine temperature and a signal from the engine water temperature sensor 50 for detecting the engine water temperature T _E are input. The computer 5 determines the fuel injection pulse width T _P based on these input information and commands it to the engine 1, or sends an ignition timing control signal (not shown) to the engine 1.
Supply to. The engine 1 is supplied with an amount of fuel according to the fuel injection pulse width T _P , and is operated by burning this fuel in synchronization with the rotation of the engine.

The automatic transmission 2 includes a torque converter 10 and a speed change gear mechanism 11 in tandem.
The engine power is input to the input shaft 12 via. The input rotation of the transmission to the shaft 12 is shifted according to the selected gear of the transmission gear mechanism 11 to reach the output shaft 13, from which the drive gear 4 is passed through the differential gear 3 to drive the vehicle. .. The speed change gear mechanism 11 controls the speed change through a control valve 15 by a speed change control computer (hereinafter referred to as ATCU) 14, and the ATCU 14 also performs a duty control of a line pressure control duty solenoid 16 in the control valve 15 by a drive duty D. Then, the line pressure in the control valve 15 is controlled.
An engine rotation sensor 6 is in this order ATCU14, vehicle speed sensor 7, the signal N _E from the throttle sensor 8, an intake air amount sensor 9 and the engine coolant temperature sensor 50, V, TH,
Enter Q and T _E respectively.

The ATCU 14 executes a control program (not shown) to determine a suitable shift speed on the basis of the vehicle speed V and the throttle opening TH, and issues a command to the control valve 15, which then controls the line pressure according to the above command. Is selectively supplied to various friction elements (not shown) in the speed change gear mechanism 11 to hydraulically operate the selected friction elements, thereby shifting the gear to the above-described suitable shift stage. At that time, AT
The CU 14 executes the control program of FIG. 3 to control the line pressure, and in the first embodiment executes the control program of FIG. 4 to correct the engine intake air amount Q which is a parameter used for the line pressure control. To do.

That is, in the control program shown in FIG. 3, which is repeatedly executed by an operating system (not shown) by a timed interrupt every predetermined period, first,
At 101, the engine speed N _E and the engine intake air amount Q are read from the engine rotation sensor 6 and the intake air amount sensor 9, respectively, and at step 102, the engine intake air amount Q is corrected (the control content of this step 102 is This will be described later in detail), and the corrected engine intake air amount Q _f is obtained by this correction. In the next step 103, the target line pressure P _L is set based on the corrected engine intake air amount Q _f and the engine speed N _E. This target line pressure P _L is set by a value Q _f / N obtained by dividing Q _f by N _{E.
Since E} is proportional to the engine output torque, and hence to the transmission input torque, for example, the line pressure control map (not shown) is looked up by Q _f / N _E to obtain the target line pressure P _L. (P _L may be obtained by calculation from the above).

In the next step 104, the target line pressure P
_The solenoid drive duty D corresponding to _L is obtained by, for example, calculation, and this duty D is output to the duty solenoid 16 in step 105. As a result, line pressure control is performed to adjust the line pressure in the control valve 15 to match the target line pressure P _L.

Next, the correction of the engine intake air amount Q by the control program of FIG. 4 will be described. This FIG. 4 is shown in FIG.
This is a control program of a subroutine corresponding to step 102 in step 1021. First, in step 1021, an engine speed dependent correction amount Q _FB for the engine intake air amount is obtained by looking up the map of FIG. 5 by the engine speed N _E. In the next step 1022, the engine water temperature dependent correction coefficient Q _T is obtained by looking up the map of FIG. 6 with the engine water temperature T _E detected by the engine water temperature sensor 50.

[0014] with Q _FB and Q _T determined as described above in the next step 1023, it calculates the effective amount of engine intake air Q _a by _{Q a = Q- (Q FB ×} Q T). Where Q is because an engine intake air amount before correction I read from the intake air quantity sensor 9, the Q _a obtained by the execution of step 1023 the correction of the engine friction that varies depending on the engine speed and the engine coolant temperature Will be added. This Q _a is Q _F = (Q
_fOLD + Q _a ) / 2 is used for the weighted average (however, Q _fOLD : the previous value of Q _a ), and the smoothed corrected engine intake air amount Q _f is obtained by this weighted average. It will be used to look up the target line pressure P _L. The calculation of Q _f by executing steps 1023 to 1024 is repeatedly performed at the above-mentioned predetermined time intervals.

Next, the correction of the engine intake air amount Q in the second embodiment by the control program of FIG. 7 will be described. 7 is a control program of a subroutine corresponding to step 102 of FIG. 3. First, at step 111, the engine speed dependent correction amount Q for the engine intake air amount is set.
_{FB is obtained} by, for example, looking up the map of FIG. 5 by the engine speed N _E (may be obtained by calculation by executing a control program (not shown)), and in the next step 112, the state of the engine is checked. If it is determined by the check of the engine state that the engine is started, the next step 113 is executed only once, and step 113 is skipped after the engine is started.

The determination of the engine start is made by the ATCU 14 based on an input signal from a sensor (not shown) or the like.
It is performed by determining that the engine is started when all four conditions of range selection, idle switch ON, vehicle speed V = 0, and engine speed> 512 rpm are satisfied (for simplification, the ON signal of the ignition switch is input. It may be determined that the engine has started). In addition, the reason why the engine start is judged by the establishment of the above four conditions is
This is because when the engine starts to start when the ignition switch is turned on while the vehicle is stopped, the engine water temperature to be used as the reference for the control in step 113 and subsequent steps differs depending on whether the engine state at that time is warm or not. This is because the conditions at the start of the engine water temperature dependence correction are made uniform.

In step 113, engine water temperature dependence correction is performed.
Coefficient Q_TInitial value Q_TOSubstitute (this initial value Q_TOIs
The map shown in FIG. 8 is obtained by the engine intake air amount sensor 9.
Look up by the detected engine intake air amount Q
To obtain). By performing this step 113
, Engine water temperature dependent correction factor Q_TThe previous value of
Rising and initial value Q_TOIs set to (Q_T=
Q_TO). This Q_TAt the next step 114 (for example,
A predetermined amount Q every 4 seconds)_DEach is subtracted (Q_T= Q
_T-Q_D), Gradually decreases over time. Note that
The subtraction in step 114 is Q _TIs below the specified value until
It is executed repeatedly every hour (however, the time limit for this subtraction
If there is, and it exceeds the time limit, Q_T= 1.0),
Q_TQ when <1.0_T= 1.0.

[0018] with Q _FB and Q _T determined as described above In the next step 115, it calculates the effective amount of engine intake air Q _a by _{Q a = Q- (Q FB ×} Q T). Where Q is because an engine intake air amount before correction I read from the intake air quantity sensor 9, the Q _a obtained by the execution of step 115 the correction of the engine friction that varies depending on the engine speed and the engine coolant temperature Will be added. This Q _a is Q _F = (Q
_fOLD + Q _a ) / 2 is used for the weighted average (however, Q _fOLD : the previous value of Q _a ), and the smoothed corrected engine intake air amount Q _f is obtained by this weighted average. It will be used to look up the target line pressure P _L. Note operation Q _f by executing the steps 115-116 are performed repeatedly at the predetermined time.

The operation of the above control is shown in FIG. 5, FIG. 8 and FIG.
An explanation will be given using (a) and (b). While the automatic transmission selectively operates various friction elements by the line pressure to select a predetermined gear and change the friction element to be operated to shift to another gear, the control program of FIG. By execution, line pressure control is performed so that the line pressure matches the target line pressure P _L. At that time, a correction for canceling the variation (increase) of the engine intake air amount due to engine friction by executing the control program of FIG. 4 or 7 with respect to the intake air amount Q as a parameter for determining the target line pressure P _L Is done.

That is, this correction is performed in step 1021 of FIG.
Alternatively, by executing step 111 of FIG. 7, a correction amount Q _FB corresponding to a portion depending on the engine speed N _E of the fluctuation of the engine intake air amount is obtained from the map of FIG. By executing 114, the correction coefficient Q _T corresponding to the portion of the above variation that depends on the engine water temperature is obtained, and by executing step 1023 or step 115, the correction amount Q _FB and The product of the correction coefficient Q _T is subtracted to obtain the effective engine intake air amount Q _a , and step 1024 or step 11
6 is executed to obtain the corrected engine intake air amount Q _f by weighted averaging Q _a.
In step 24 or steps 111 to 116, the ATCU 14 functions as an intake air amount correction means. Q _f which is a result obtained in this correction, FIG. 9 (a), the from becomes to cancel the engine intake air amount variation dependent on the engine speed and the engine coolant temperature as (b), the the Q _f The line pressure controlled by the target line pressure P _L obtained by using is always an appropriate value according to the transmission input torque regardless of the engine temperature state (cooling or warming up), and the shift shock characteristic becomes good.

Further, in the correction of the engine intake air amount, the correction coefficient Q _T corresponding to the engine water temperature is obtained by subtracting the predetermined amount Q _D by a predetermined amount after the engine start condition is satisfied by executing steps 112 to 114. However, the ATCU 14 functions as an engine warm-up condition detecting means in steps 112 to 114. However, as is clear from FIG. 9B, the engine water temperature is linearly proportional to the engine intake air amount and time. I'm taking advantage of that. For example, when the engine is started in a cold state, the engine intake air amount Q is large, the initial value Q _TO set in step 113 becomes larger than the map of FIG. 8, and thereafter, the predetermined value Q _D Is subtracted from the initial value Q _TO , but it takes a lot of time for Q _T to reach 1.0, so warm-up correction is performed. On the other hand, when the engine is started in a warm state, the engine intake air amount Q is small and the Q _TO set in step 113 is Q _TO =
It becomes 1.0 and warm-up correction is not performed. In this way, the engine water temperature can be estimated from the elapsed time after the engine start condition is satisfied without providing the engine water temperature sensor,
The cost can be reduced. Further, by setting the engine start condition, even if there are individual differences in the engine, variations in oil, and the like, the states at the time of reading the initial value Q _TO are made uniform, so it is possible to absorb them.

[0022]

As described above, the line pressure control device for an automatic transmission according to the present invention, as described above, adds a correction to the detected engine intake air amount to cancel the variation of the engine intake air amount depending on the engine warm-up state. Regardless of the engine temperature, the line pressure can be controlled to an appropriate value according to the transmission input torque.
It is possible to improve the shift shock characteristics of the automatic transmission both during warm-up.

[Brief description of drawings]

FIG. 1 is a conceptual diagram of the present invention.

FIG. 2 is a diagram showing a power train control system of an automobile incorporating the device of the present invention.

FIG. 3 is a flow chart showing a control program for line pressure control by the shift control computer in the first embodiment.

FIG. 4 is a flowchart showing a control program for engine intake air amount correction by the shift control computer in the same example.

FIG. 5 is a map illustrating an engine rotation speed-dependent correction amount of the same example.

FIG. 6 is a map illustrating an engine water temperature dependent correction coefficient of the same example.

FIG. 7 is a flowchart showing a control program for engine intake air amount correction by a shift control computer in the second embodiment.

FIG. 8 is a map illustrating an engine water temperature-dependent correction coefficient of the same example.

FIG. 9A is a diagram showing a relationship between an engine speed and an engine intake air amount, and FIG. 9B is a diagram showing a relationship between an engine water temperature and an engine intake air amount.

[Explanation of symbols]

 1 Electronically controlled fuel injection engine 2 Automatic transmission 6 Engine rotation sensor 9 Intake air amount sensor 11 Transmission gear mechanism 14 Transmission control computer (ATCU) 15 Control valve 16 Line pressure control duty solenoid 50 Engine water temperature sensor

Claims (2)

[Claims] 1. The target setting means sets a target line pressure based on the engine intake air amount detected by the intake air amount detecting means and the engine speed detected by the engine rotation detecting means, and the line pressure is set to the target line pressure. In a line pressure control device for an automatic transmission, wherein the adjusting means adjusts the line pressure of the automatic transmission, an engine warm-up state detecting means for detecting an engine warm-up state, and a detection of the warm-up state detecting means. A line pressure control device for an automatic transmission, comprising an intake air amount correction means for correcting an engine intake air amount based on a result. 2. The line pressure control device for an automatic transmission according to claim 1, wherein the engine warm-up state detection means depends on a detected value of an engine intake air amount at the time of starting the engine.