JPH03224833A - Line pressure control device for automatic transmission - Google Patents

Abstract

PURPOSE:To obtain a true intake air volume and enhance control accuracy by performing the inverse operation of the intake air volume from the result of the correction of a fuel supply amount based on a detected value, regardless of any difference in the intake air volume based on the detected value of an engine operation parameter. CONSTITUTION:A fuel supply control device A detects an air volume parameter with an air volume parameter detection means B, and a fuel supply amount is operated with a fuel supply amount operation means C, based upon the result of the detection. Also, the air-fuel ratio of a mixture is detected with an air-fuel ratio detection means D, and the fuel supply amount is so corrected with an air-fuel ratio control means E as to bring the result of the detection near a target air-fuel ratio. Furthermore, the fuel supply amount is controlled with a fuel supply control means F, depending upon the corrected fuel amount. In the aforesaid construction, an intake air volume is inversely operated with an intake air volume reverse operation means G. Also, line pressure is set up with a line pressure setting means H, on the basis of the inversely operated intake air volume. Furthermore, a line pressure control signal corresponding to the set line pressure is outputted to the hydraulic circuit K of an automatic transmission J by a control signal output means I.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a line pressure control device for an automatic transmission, and more particularly, to a device for controlling the line pressure of an automatic transmission with a torque converter mounted on an automobile.

<Prior art> In automobiles equipped with automatic transmissions equipped with torque converters, the oil discharged from the oil pump is adjusted to an appropriate line pressure according to the throttle valve opening of the engine, and each shift of the automatic transmission is Typically, it supplies the hydraulic circuit that controls the element.

By the way, the line pressure needs to be adjusted to an appropriate oil pressure according to the output torque of the engine; if it is higher than the appropriate oil pressure, the torque transmission rate will be high and engine vibrations and shift shocks will be transmitted to the axle. , noise and vibration will increase.

Furthermore, if the oil pressure is lower than the appropriate oil pressure, the engagement force of the gears etc. will be weakened, unnecessary slips will occur, the transmission efficiency will be significantly reduced, and in the worst case, there is a risk that the clutch etc. will break due to friction.

In this regard, in the method of adjusting line pressure using only the throttle valve opening as a parameter for engine output torque, the throttle valve opening does not necessarily accurately reflect the engine output torque, so the engine output torque There was a problem in that the corresponding line pressure could not be set accurately.

Therefore, various devices have been proposed that are configured to detect the intake air amount of the engine, which is approximately proportional to the engine output torque, and to control the line pressure based on this intake air amount (Japanese Patent Laid-Open No. 6
2-9054, etc.).

In other words, in an internal combustion engine equipped with an air flow meter that detects the intake air flow rate of the engine, the intake air flow rate detected by the air flow meter is divided by the engine rotation speed N to find the intake air amount per engine rotation. Set the engine output torque as a value proportional to the intake air amount, or
The amount of intake air proportional to the engine output torque is determined by determining the amount of intake air from the intake pressure and further predicting the amount of intake air from the throttle valve opening and engine rotational speed.

<Problems to be Solved by the Invention> However, when determining the line pressure based on the intake air flow rate detected by an air flow meter, if the true intake air flow rate cannot be detected due to deterioration of the air flow meter or variations in characteristics, This deteriorates the line pressure setting accuracy, making it impossible to stably obtain an appropriate line pressure.

Furthermore, when determining the intake air flow rate from the throttle valve opening degree and the engine rotational speed, it becomes impossible to detect the true intake air amount due to changes in air density (changes in altitude), dirt on the throttle valve, etc.

Furthermore, when determining the amount of intake air based on intake pressure, it becomes impossible to detect the true amount of intake air (fresh air amount) due to the influence of exhaust pressure and EGR.

As described above, in either case, it is difficult to stably determine the true intake air amount, and it is not possible to accurately control the line pressure in accordance with the true engine output torque.

The present invention has been made in view of the above-mentioned problems, and uses detected values of parameters related to the intake air amount (intake air flow rate, intake pressure, throttle valve opening degree) as described above.
It is an object of the present invention to improve the accuracy of line pressure control by making it possible to accurately determine the amount of intake air which is a value equivalent to engine output torque.

<Means for Solving the Problems> Therefore, in the present invention, as shown in FIG. In the line pressure control device for the automatic transmission to be controlled, first, the fuel supply control device for the internal combustion engine adjusts the fuel supply amount based on an operating parameter related to the intake air amount of the internal combustion engine detected by the air amount parameter detection means. While the calculation means calculates the fuel supply amount, the air-fuel ratio control means corrects and sets the fuel supply amount so that the air-fuel ratio of the engine intake air-fuel mixture detected by the air-fuel ratio detection means approaches the target air-fuel ratio. The fuel supply means is configured to control the fuel supply to the engine based on the resulting fuel supply amount, and the line pressure control device is configured such that the intake air amount back calculation means adjusts the amount of fuel corrected by the air-fuel ratio control means. The intake air amount of the engine is determined by back calculation based on the supply amount, and the line pressure setting means sets the line pressure based on the intake air amount calculated by back calculation. The control signal output means is configured to output a line pressure control signal corresponding to the set line pressure to the hydraulic circuit of the automatic transmission.

<Operation> According to this configuration, the air-fuel ratio control means corrects and sets the fuel supply amount so that the air-fuel ratio of the engine intake air-fuel mixture approaches the target air-fuel ratio, so that the corrected fuel supply amount is equal to the true intake air. The value is commensurate with the quantity.

Therefore, even if the fuel supply amount calculated based on the operating parameters related to the intake air amount does not correspond to the true intake air amount, the true value can be calculated from the fuel supply amount corrected by the air-fuel ratio control means. If you control the line pressure by treating this true intake air amount as a value proportional to the engine output torque, you can control the line pressure to a value that corresponds to the true engine output torque. can.

<Example> The present invention will be explained in detail below.

In FIG. 2 showing the configuration of one embodiment, first, the components of the automatic transmission will be explained.

The oil pump 1 is driven by the output shaft of the engine 12 via a torque converter, that is, by the input shaft of the transmission. The electromagnetic valve 2 obtains a pilot pressure based on the discharge pressure of the oil pump 1 which is duty-controlled by a signal from the control unit 11 and guided through the orifice 3.

This pilot pressure is the pressure modifier valve 4
After being amplified by the pressure regulator valve 5, the pressure regulator valve 5 adjusts the discharge pressure from the oil pump 1 to a line pressure proportional to the pilot pressure, and outputs the pressure to the torque converter (power transmission) 6. For lubrication 7. For cooling 89 For generating hydraulic pressure 9. It is sent to each of the other 10 hydraulic circuits. Note that there is a valve at the end of the circuit 9 for generating hydraulic pressure, which operates the clutch, brake, etc. in combination according to the gear position.

A control unit 11 with a built-in microcomputer that duty-controls the electromagnetic valve 2 receives an intake air flow rate Q' signal from a control unit 13 for fuel injection (fuel supply) control, while a rotational speed sensor 14 detects the signal. engine rotational speed Ne (rotational speed of the input shaft for the automatic transmission), vehicle speed sensor 15
The vehicle running speed VSP detected by the output rotation speed sensor 16, the rotation speed No. of the output shaft of the automatic transmission detected by the output rotation speed sensor 16, and the opening degree TVO of the throttle valve 18 detected by the throttle sensor 17 are input. .

Further, the control unit 13 for controlling the fuel injection
calculates the fuel injection amount (fuel supply amount) Ti based on detection signals from various sensors, and sends a drive pulse signal with a pulse width corresponding to this fuel injection amount Ti at a timing synchronized with the engine rotation to the electromagnetic fuel By outputting to the injection valve 19, fuel supply to the engine 12 is controlled.

The various sensors include the rotational speed sensor 14.
In addition to the throttle sensor 17, there is an intake air temperature sensor 21 that detects the intake air temperature TA in the air cleaner section 20. Intake air flow rate Q
Butterfly type air flow meter 22. Water temperature sensor for detecting cooling water temperature Tw23. Further, an oxygen sensor 25 is provided as an air-fuel ratio detecting means for detecting whether the engine intake air-fuel mixture is rich or lean with respect to the stoichiometric air-fuel ratio by detecting the oxygen concentration in the exhaust gas in the exhaust passage 24.

Note that the air flow meter 22 is not limited to the butterfly type, but may be of the hot wire type, Karman vortex type, or the like. Further, in fuel supply control, a configuration may be adopted in which an intake pressure sensor 26 that detects the intake pressure (boost) PB is provided instead of the air flow meter 22, or the air flow meter 22 and the intake pressure sensor 26 are not both provided. , the basic fuel injection amount Tp may be set based on the detected values of the rotational speed sensor 14 and the throttle sensor 17 as described later.

Next, the setting control of the intake air flow rate Q'' signal outputted from the control unit 13 for fuel injection control to the control unit 11 for automatic transmission control will be explained based on the program shown in the flowchart of FIG.

The program shown in the flowchart of FIG. 3 is processed by the control unit 13 for fuel injection control, and is generally used to set the basic fuel injection amount Tp based on the intake airflow IQ detected by the airflow meter 22. In the case of a fuel control method called the JETRO method, in the case of a fuel control method generally called the D-JETRO method in which the basic fuel injection 4jLTp is set based on the intake pressure PB detected by the intake pressure sensor 26, and in the case of a fuel control method called the D-JETRO method, the basic fuel injection amount TP is set based on the intake pressure PB detected by the intake pressure sensor 26. The figures are shown separately for a fuel control method that is set based on the opening area A of the intake system and the engine rotational speed Ne.

First, we will explain the case where the basic fuel injection amount Tp is set based on the opening area A and the engine rotational speed Ne. In this case, the program is executed at predetermined minute intervals (for example, every 10 m5), This is Sl.

(Similarly below), the opening degree TVO of the throttle valve 18 detected by the throttle sensor 17 and the engine rotation speed Ne detected by the rotation speed sensor 14 are respectively input.

In the next step 2, the throttle valve opening degree TVO input in step 1 is converted into an opening area of 1 A of the engine intake system.

In step 3, the basic volumetric efficiency QHφ is searched from the map based on the value obtained by dividing the opening area A by the engine rotational speed Ne.

Then, in step 4, the basic volumetric efficiency QHφ obtained in step 3 is calculated based on the engine rotational speed Ne and the basic volumetric efficiency Q.
The volumetric efficiency QCYL is obtained by correcting with a correction coefficient based on Hφ and a correction coefficient based on the intake air temperature TA.

In step 5, the volumetric efficiency QC obtained in step 4 is
A basic fuel injection amount Tp corresponding to the intake air amount is calculated by multiplying YL by a predetermined constant KCONA.

On the other hand, the setting control of the basic fuel injection amount Tp in the D-JETRO system is shown in step 11.12.

First, in step 11, the intake pressure PB detected by the intake pressure sensor 26 is input, and in the next step 12, this intake pressure PB, a correction coefficient based on the intake pressure PB, and the intake pressure PB and the engine rotation speed Ne are input. a small correction factor based on,
A basic fuel injection amount 2'rp is calculated based on a correction coefficient based on the intake air temperature TA and a constant NC0ND.

Further, the setting control of the basic fuel injection amount Tp in the L-JETRO system is shown in steps 21 to 23.

First, in step 21, a voltage signal Us output from the air flow meter 22 in accordance with the intake air flow rate Q is input.

Then, in the next step 22, the voltage signal Us is converted into an intake air flow rate Q, and in step 23, the basic fuel injection amount Tp (←KxQ/ Ne) is calculated.

After calculating the basic fuel injection amount Tp based on each fuel control method, the process proceeds to step 31, where it is determined whether the cooling water temperature Tw detected by the water temperature sensor 23 exceeds a predetermined value.

Here, if the cooling water temperature Tw exceeds the predetermined value, the process advances to step 32 and determines whether the current operating condition is included in the air-fuel ratio feedback control region divided by the basic fuel injection amount Tp and the engine rotational speed Ne. Determine whether or not.

3. When the operating conditions are such that feedback control of the air-fuel ratio is performed, the process proceeds to step 33 to execute setting control of the air-fuel ratio feedback correction coefficient LMD.

The air-fuel ratio feedback correction coefficient LMD is set and controlled by, for example, proportional/integral control, and when the air-fuel ratio detected by the oxygen sensor 25 is rich (lean) with respect to the target air-fuel ratio (stoichiometric air-fuel ratio), it is initially set to a predetermined value. The correction coefficient LMD is decreased (increased) by the proportional bone P, and then gradually decreased (increased) by the predetermined integral ■, so that the air-fuel ratio of the engine intake air-fuel mixture repeats rich and lean around the target air-fuel ratio. be.

On the other hand, when it is determined in step 31 that the cooling water temperature Tw is below the predetermined value, or when it is determined in step 32 that it is not in the feedback control region, feedback control of the air-fuel ratio is not executed, and in step 36, the basic fuel The intake air flow rate Q' is calculated backward from the injection amount Tp.

In step 36, the basic fuel injection amount Tp is calculated using the simplest and JETRO method calculation formula (Tp←KxQ
/N), it is assumed that the basic fuel injection amount Tp has been calculated even in cases other than the L-JETRO system, and the calculation to back-calculate the intake air flow rate Q'' is performed as follows.In addition, in step 33, the air-fuel ratio feedback correction is performed. Coefficient L
When MD setting control is performed, the basic fuel injection amount Tp is corrected based on the air-fuel ratio feedback correction coefficient LMD and other correction terms to calculate the final fuel injection amount Ti.

Here, it is assumed that the basic fuel injection amount Tp is corrected based on the following formula to calculate the fuel injection amount Ti.

T i←2Tp XLMDXKBLRCXCOEF+T
s In the calculation formula for the fuel injection amount Ti above, KBLRC
is an air-fuel ratio learning correction coefficient obtained by learning the deviation of the air-fuel ratio feedback correction coefficient LMD from the reference value for each operating condition, and by correction by this air-fuel ratio learning correction coefficient KBLRC, 5 by the correction coefficient LMD is obtained. This is done so that the air-fuel ratio can be obtained.

Further, C0EF is various correction coefficients including various correction terms such as a post-start increase correction coefficient, and Ts is for correcting changes in the effective valve opening time of the electromagnetic fuel injection valve 19 due to battery voltage. It is a correction bone.

A drive pulse signal with a pulse width corresponding to the fuel injection amount Ti thus set is output to the fuel injection valve 19 in synchronization with the engine rotation, thereby controlling the fuel supply to the engine 12. Note that when the air-fuel ratio feedback control is not performed, the fuel injection amount Ti is calculated by clamping the air-fuel ratio feedback correction coefficient 'LMD in the Ti calculation formula.

In the next step 35, the intake air flow rate Q' is calculated by back calculating from the fuel supply amount Ti calculated in step 34 according to the following formula.

In the above calculation formula, Tp in the back calculation formula for the intake air flow rate Q" in step 36 is (Ti-Ts)/2xCOEF, and the true basic fuel injection amount 'rp is assumed to be Tp XLMDXKBLRCT: I'm thinking.

That is, since the air-fuel ratio feedback correction control is to compensate for the air-fuel ratio deviation due to the basic fuel injection amount 'rp not matching the true intake air amount, TpXLMD
XKBLRC is the fuel injection amount commensurate with the true intake air amount, and for example, there are variations in the characteristics of the air flow meter 22, the influence of air density on the value detected by the intake pressure sensor 26, and
The setting error of the basic fuel injection amount Tp due to the influence of throttle valve dirt and air density in fuel control based on the throttle valve opening degree TVO and engine rotational speed Ne, that is, the estimated error of the intake air amount, is corrected by the above-mentioned LMDXKBLRC. This means that it has been done.

Therefore, even if there is an estimated error in the intake air amount in various fuel control methods, the true intake air flow rate Q can be determined by the above-mentioned back calculation formula. In other words, step 36
The intake air flow rate Q'' that is back-calculated is a value that includes an error affected by the detection error of each sensor, but when the air-fuel ratio is feedback-controlled, the detection error is compensated for by the air-fuel ratio feedback control. Thus, the true intake air flow rate Q' can be determined.

In step 35 or step 36, the intake air flow rate Q'' is calculated backward, and in step 37, this intake air flow rate Q'' is transferred to the control unit 11 for controlling the automatic transmission.

As explained above, in this embodiment, the functions of the fuel supply amount setting means, the air-fuel ratio control means, and the fuel supply control means are provided in the control unit 11 in the form of software, and the air amount parameter detection means is , air flow meter 22. Intake pressure sensor 26. The operating parameters that the throttle sensor 179 and rotational speed sensor 14 correspond to and are related to the intake air amount of the internal combustion engine are the intake air flow rate Q, intake pressure PB, throttle valve opening TVO, and engine rotational speed Ne detected by these. be.

Here, a control unit 11 for automatic transmission control
The line pressure control processed by will be explained according to the programs shown in the flowcharts of FIGS. 48 and 5. In this embodiment, the functions of the intake air amount back calculation means, the line pressure setting means, and the control signal output means are provided in the form of software as shown in the flowcharts of FIGS. 4 and 5.

The program shown in the flowchart of FIG. 4 is executed at predetermined minute intervals. First, in step 41, a signal of the intake air flow rate Q'' transferred from the control unit 13 for fuel injection control is input. In the next step 42, an engine output torque equivalent value (torque) is set based on the intake air flow rate Q'' based on the following equation.

Here, KT is a constant, No is the rotation speed No of the output shaft of the automatic transmission detected by the output rotation speed sensor 16, and Ne is the engine rotation speed (rotation speed of the input shaft for the automatic transmission). The constant multiplied is for subtracting losses due to engine auxiliary equipment.

The value equivalent to the engine output torque set by the above calculation formula is equal to the true engine output torque because the intake air flow rate Q' is a value commensurate with the true intake air amount when air-fuel ratio feedback control is performed. It can be done with the corresponding i-direction.

When the engine output torque equivalent value is set in this way,
In the next step 43, the basic line pressure PLφ is searched and determined from a map corresponding to the torque.

Similarly, in step 44, line pressure PL12. PL23. PL34 is found by searching from a map corresponding to the torque.

The line pressures PLφ, PL12.
PL23. Actual line pressure control based on PL34 is performed according to the program shown in the flowchart of FIG.

The program shown in the flowchart of FIG. 5 is executed at minute intervals, and first, in step 51, based on the shift pattern MA0 which is preset using the vehicle speed SP and the throttle valve opening TVO as parameters, Gear position ne corresponding to current operating conditions
x Identify tgp.

Then, in the next step 52, it is determined whether or not a shift operation is necessary by comparing the gear position nextgp obtained based on the shift pattern in step 51 with the current gear position cugp. Gear position nextgp determined based on the shift pattern and current gear position cugp
If they match, there is no need to perform a speed change operation, and the process proceeds to step 53, in which the electromagnetic valve 2 is adjusted to a predetermined value so that the basic line pressure PLφ obtained in step 43 in the flowchart of FIG. 4 is reached. A line pressure control signal (drive pulse signal) with a duty ratio is output so that the working oil pressure corresponding to the line pressure PLφ is sent to each hydraulic circuit.

On the other hand, when it is determined in step 52 that the gear position nextgp obtained based on the shift pattern and the current gear position cugp do not match, and a shift operation is necessary, the appropriate gear position is determined depending on which gear to shift from. Select and adjust the line pressure to reduce shift shock during shift changes (S1 chips 54 to 58).

<Effects of the Invention> As explained above, according to the present invention, even if there is an error in the intake air amount determined based on the detected values of operating parameters related to the intake air amount of the engine, fuel supply based on these detected values can be performed. Since the amount of intake air is calculated backwards from the result of air-fuel ratio feedback correction, the true amount of intake air can be determined, and the line pressure of the automatic transmission can be variably controlled according to the true engine output torque. This has the effect of making it possible to

[Brief explanation of drawings]

Fig. 1 is a block diagram showing the configuration of the present invention, Fig. 2 is a system schematic diagram showing an embodiment of the invention, and Fig. 3 shows the control contents processed by the control unit for fuel injection control in the same embodiment. Flowcharts shown in FIGS. 4 and 5
Each figure is a flowchart showing the control contents processed by the control unit for automatic transmission control in the above embodiment. 2 1...Oil pump 2...Solenoid valve 6~
10...Hydraulic circuit 11...Control unit for automatic transmission control 12...Internal combustion engine Engineering 3...
Control unit for fuel injection control 14...Rotational speed sensor ■7...Throttle sensor 18
...Throttle valve 19...Intake pressure sensor 2
2...Air flow meter

Claims (1)

[Scope of Claims] A line pressure control device for an automatic transmission that controls line pressure supplied to a hydraulic circuit that controls each transmission element of an automatic transmission constituting a power transmission system of an internal combustion engine, comprising: an air amount parameter detection means for detecting an operating parameter related to the air amount; and a fuel supply amount calculation means for calculating the fuel supply amount based on the operating parameter related to the intake air amount detected by the air amount parameter detection means. , an air-fuel ratio detection means for detecting an air-fuel ratio of an engine intake air-fuel mixture; an air-fuel ratio control means for correcting and setting the fuel supply amount so that the air-fuel ratio detected by the air-fuel ratio detection means approaches a target air-fuel ratio; The internal combustion engine includes a fuel supply control device configured to include: fuel supply control means for controlling fuel supply to the engine based on the fuel supply amount corrected and set by the air-fuel ratio control means; An intake air amount back calculation means that back calculates the intake air amount of the engine based on the fuel supply amount corrected and set by the control means, and a line pressure is set based on the intake air amount calculated by the intake air amount back calculation means. and control signal output means for outputting a line pressure control signal corresponding to the line pressure set by the line pressure setting means to the hydraulic circuit of the automatic transmission. Automatic transmission line pressure control device.