JP2002243029A - Hydraulic control device for automatic transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To minimize influence on ordinary shift control by performing air exhaust control only when air is actually mixed in a hydraulic circuit. SOLUTION: When turning on an ignition switch (S1), a reference temperature TMP (S2, 3) according to an outside air temperature is compared with a cooling water temperature (S4) (S5), and when a water temperature is lower than the reference temperature TMP, it is estimated that the air is mixed in at engine stopping time (S7), and when the air exhaust control is not completed (S6) at last time operation time even if the water temperature is higher than the reference temperature TMP, it is estimated that the air remains (S7). When the air is mixed in, hydraulic pressure is forcedly supplied only for a prescribed time to a frictional engaging element to be originally released (S9 to S12).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic control device for an automatic transmission, and more particularly, to a hydraulic control for discharging air mixed in a hydraulic circuit.

[0002]

2. Description of the Related Art Conventionally, in a hydraulic control device of an automatic transmission for hydraulically controlling the engagement and release of a friction engagement element, a friction engagement to be released from a request for a shift speed during non-shifting. A configuration is known in which hydraulic pressure is periodically supplied to elements (clutches and brakes) within a range in which the piston does not stroke to discharge air mixed in a hydraulic circuit (Japanese Patent Laid-Open No. 10-169768). reference).

[0003]

In the above-described air discharge control, the hydraulic pressure is supplied to the frictional engagement element that should be released from the request of the shift speed at that time. If the engagement control is started on the basis of the shift request during the engagement, the engagement control is started from an initial pressure higher than usual, so that the engagement is quickened and a shift shock may be generated. .

Therefore, it is preferable that the air discharge control be performed only when air is actually mixed in the hydraulic circuit, but conventionally, it is determined whether or not air is actually mixed. In this case, the hydraulic pressure is supplied for discharging the air even though the air is not actually mixed in, and this may have an unnecessary adverse effect on the shift control. There was a problem.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and determines whether air (bubbles) is mixed in a hydraulic circuit, and forcibly supplies hydraulic pressure only when air is actually mixed. Is performed, so that the influence on the shift can be avoided as much as possible.

[0006]

Therefore, according to the present invention, the hydraulic circuit is forcibly supplied to the frictional engagement element to be released at the current shift speed during the non-shifting operation. In a hydraulic control device for an automatic transmission that discharges air mixed therein, a suspension period of the supply of hydraulic pressure to the hydraulic circuit is determined, and only when the suspension period exceeds a predetermined period, a forced operation for discharging the air is performed. It was configured to supply a proper hydraulic pressure.

With this configuration, when the period of time during which the hydraulic circuit is not supplied to the hydraulic circuit without being supplied exceeds a predetermined period, it is assumed that air is mixed in the hydraulic circuit and the hydraulic circuit should be released. Although the hydraulic pressure is supplied to the friction engagement element, if the idle period is equal to or less than the predetermined period, it is estimated that there is no air in the hydraulic circuit, and the hydraulic pressure is not supplied to the friction engagement element that should be released. .

The stop period includes a period measured by time and a period determined by a change in a state quantity such as temperature. According to the second aspect of the present invention, an automatic transmission for discharging air mixed in a hydraulic circuit by forcibly supplying a hydraulic pressure to a friction engagement element to be released at a current shift speed during a non-shift operation. In the hydraulic control device of the machine, the forced hydraulic pressure supply for air discharge is performed only when the temperature of the engine or the automatic transmission at the time of starting the engine combined with the automatic transmission falls below the reference temperature. It was configured as follows.

With this configuration, when the temperature of the engine or the automatic transmission at the time of starting is lower than the reference temperature, a predetermined time or more has elapsed since the previous operation, and air is mixed into the hydraulic circuit during that time. Presumed that
Hydraulic supply to the friction engagement element that should be released is performed, but if the temperature at the time of startup is high, it is restarted within a short time from the previous operation, and there is no air in the hydraulic circuit Judgment is made and hydraulic pressure is not supplied.

According to a third aspect of the present invention, the engine coolant temperature is determined as a parameter representative of the engine temperature. According to a fourth aspect of the present invention, the temperature of the hydraulic oil of the automatic transmission is determined as a parameter representing the temperature of the automatic transmission. Claim 5
In the described invention, the reference temperature is changed to be lower as the outside air temperature is lower.

According to this configuration, when the outside air temperature is low, the temperature of the engine or the automatic transmission decreases rapidly with time, so the reference temperature is set lower as the outside air temperature is lower. According to the sixth aspect of the present invention, an automatic transmission for discharging air mixed in a hydraulic circuit by forcibly supplying a hydraulic pressure to a friction engagement element to be released at a current shift speed during a non-shift operation. In the hydraulic control device of the machine, only when the stop time of the engine combined with the automatic transmission exceeds the reference time, the forced hydraulic supply for discharging the air is performed.

With this configuration, when the engine stop time exceeds the reference time, it is presumed that air is mixed in the hydraulic circuit during that time, and hydraulic pressure is supplied to the friction engagement element that should be released. However, when the stop time is short, it is estimated that air has not entered the hydraulic circuit, and the hydraulic pressure is not supplied. In the invention according to claim 7,
At the time of starting the engine, it is determined whether or not the air discharge control has been completed during the previous operation, and if not, the forced operation for discharging the air has priority over the determination of the temperature or the stop time. It was configured to supply hydraulic pressure.

According to this configuration, even if the engine is stopped and restarted within a short period of time, if the air discharge control is not completed in the previous operation, the immediately preceding stop period Even if air is not mixed in, there is a possibility that the air mixed before that may remain without being discharged, so hydraulic supply for discharging air is forced.

[0014]

According to the first aspect of the present invention, it is possible to estimate the presence or absence of air mixing in the hydraulic circuit from the period during which the supply of hydraulic pressure to the hydraulic circuit is stopped. The hydraulic pressure can be supplied only when the power is on, and the effect on the normal shift control can be minimized.

According to the second to fourth aspects of the present invention, the period during which the supply of the hydraulic pressure to the hydraulic circuit is stopped can be easily determined from the temperature at the time of restart, and the hydraulic pressure is limited only when air is actually mixed. There is an effect that the supply can be easily realized. According to the fifth aspect of the invention, even when the outside air temperature is different, there is an effect that the period during which the supply of the hydraulic pressure to the hydraulic circuit is stopped can be accurately determined from the temperature at the time of restart.

According to the sixth aspect of the present invention, it is possible to accurately determine the time during which the supply of the hydraulic pressure to the hydraulic circuit is stopped due to the stop of the engine, and to more accurately determine whether or not air is actually mixed into the hydraulic circuit. It has the effect of being able to judge. According to the seventh aspect of the present invention, it is possible to prevent the air discharge control from being canceled due to a short stop period even though the air remains without being completely discharged, and the air is reliably discharged. There is an effect that can be made.

[0017]

Embodiments of the present invention will be described below. FIG. 1 shows a drive system of a vehicle according to an embodiment. An automatic transmission 3 is connected to an output shaft of an engine 1 via a torque converter 2.
The drive shaft of the vehicle (not shown) is driven to rotate by the output shaft of (1).

FIG. 2 is a skeleton showing a transmission mechanism of the automatic transmission 3. The transmission mechanism includes two sets of planetary gears G1, G2 and three sets of multi-plate clutches (high clutch H
/ C, reverse clutch R / C, low clutch L /
C) One set of brake bands 2 & 4 / B, one set of multiple disc brakes (low & reverse brake L & R / B), and one set of one-way clutch L / OWC.

The two sets of planetary gears G1 and G2 are simple planetary gears including sun gears S1 and S2, ring gears r1 and r2, and carriers c1 and c2, respectively. The sun gear S1 of the planetary gear set G1 has a reverse clutch R /
C is configured to be connectable to the input shaft IN, and is configured to be fixable by the brake bands 2 & 4 / B.

The sun gear S2 of the planetary gear set G2 is directly connected to the input shaft IN. The carrier c1 of the planetary gear set G1 is configured to be able to be coupled to the input shaft IN by a high clutch H / C, while the ring gear r2 of the planetary gear set G2 is connected to the carrier of the planetary gear set G1 by a low clutch L / C. The carrier c1 of the planetary gear set G1 can be fixed by a low & reverse brake L & R / B.

A ring gear r1 of the planetary gear set G1 and a carrier c2 of the planetary gear set G2 are directly connected to the output shaft OUT. In FIG. 2, reference numeral 21 denotes an oil pump (hydraulic pump) driven by the engine 1 and supplying hydraulic oil to the automatic transmission. In the transmission mechanism having the above-described structure, the first to fourth forward speeds
As shown in FIG. 3, the speed and the reverse R are realized by a combination of the engaged / released state of each clutch / brake (friction engagement element).

In FIG. 3, a circle indicates a fastened state, and a part without a symbol indicates a released state.
The fastening state indicated by a black circle of & R / B indicates fastening only in one range. The engagement / disengagement logic of the friction engagement element is realized by a combination of ON / OFF of the shift solenoid (A) 5 and the shift solenoid (B) 6 inserted in the shift control valve 4 shown in FIG. (See FIG. 4).

A line pressure solenoid 7 is inserted in the control valve 4, and the line pressure of the control valve 4 is controlled by the line pressure solenoid 7. The shift solenoid (A) 5, the shift solenoid (B) 6, and the line pressure solenoid 7 are controlled by an A / T controller 11. The A / T controller 11 includes an ATF temperature sensor 12 for detecting the temperature of an ATF (Automatic Transmission Fluid (hereinafter, referred to as ATF)), and a throttle valve for performing an intake throttle of the engine 1 in conjunction with an accelerator pedal (not shown). 8, a throttle opening sensor 13, which detects the opening TVO,
The vehicle speed sensor 14 detects the running speed VSP of the vehicle, the engine rotation sensor 15 detects the rotation speed Ne of the engine 1, the inhibitor switch 16 detects the range position selected by operating the shift knob, and the water temperature that detects the cooling water temperature of the engine 1. A detection signal is inputted from a sensor 17, an outside air temperature sensor 18 for detecting the outside air temperature, an oil temperature sensor 19 for detecting the temperature of the lubricating oil of the engine 1, and an ON / OFF signal from an ignition switch 20, etc. You.

The A / T controller 11
While performing normal shift control based on the various detection signals described above, the control program shown in the flowchart of FIG. 5 is executed to discharge air (bubbles) mixed in the hydraulic circuit while the vehicle is left unattended. Control. FIG.
In step S1, it is determined whether or not the ignition switch 20 is switched from OFF to ON. When the ignition switch 20 is switched ON, the process proceeds to step S2.

In step S2, a detection signal from the outside air temperature sensor 18 is read to detect the outside air temperature. In step S3, a reference temperature TMP is set according to the outside air temperature detected in step S2. The reference temperature TM
P is set to a higher temperature as the outside air temperature increases.

In step S4, a detection signal from the water temperature sensor 17 is read to detect the temperature of the cooling water. The cooling water temperature is a parameter representative of the temperature of the engine 1. Instead of the cooling water temperature, the temperature of the lubricating oil may be detected based on a detection signal from the oil temperature sensor 19,
Further, the temperature of the ATF representing the temperature of the automatic transmission 3 may be detected based on a detection signal from the ATF temperature sensor 12 instead of the temperature of the engine 1.

In step S5, the coolant temperature (or lubricating oil temperature or ATF temperature) detected in step S4 is compared with the reference temperature TMP set in step S3.
When the cooling water temperature (or lubricating oil temperature or ATF temperature) detected in step S4 is lower than the reference temperature TMP, the process proceeds to step S7, and it is estimated that air is mixed in the hydraulic circuit.

The cooling water temperature (or lubricating oil temperature or AT
The state in which the temperature (F temperature) is lower than the reference temperature TMP indicates that a predetermined time or more has elapsed since the engine 1 was stopped, and the state where the hydraulic pressure supply to the hydraulic circuit was stopped for the predetermined time or more was left. As a result, mixing of air into the hydraulic circuit is expected. On the other hand, when the cooling water temperature (or lubricating oil temperature or ATF temperature) detected in step S4 is equal to or higher than the reference temperature TMP, the process proceeds to step S6.

In step S6, it is determined whether the air discharge control was performed during the previous operation and whether the air discharge control was performed only for a predetermined period. In step S6,
If it is determined that the air discharge control has not been performed during the previous operation, or if it has been determined that the air discharge control has been performed but the engine 1 has been stopped incompletely without being performed to the end, the process proceeds to step S7. It is estimated that air is mixed in the hydraulic circuit.

If the air discharge control is performed during the previous operation and the air discharge control is performed only for a predetermined period, and the air discharge is completed, the process proceeds to step S8.
Then, it is estimated that air is not mixed in the hydraulic circuit. If the coolant temperature (or lubricating oil temperature or ATF temperature) detected in step S4 is equal to or higher than the reference temperature TMP, it means that the engine 1 has been stopped and restarted before the temperature has dropped significantly. It is presumed that no air was mixed during this period because the period during which was stopped was short.

However, if the air discharge control has not been completed during the previous operation, there is a possibility that the air mixed in before that may remain without being discharged. Even if is short, if the air discharge control is not completed during the previous operation, the state of air mixing is estimated. If it is determined in step S8 that air is not mixed, the program is terminated without performing hydraulic supply control for discharging air.

Therefore, the air discharge control is performed in a state where the air is not actually mixed, thereby avoiding adverse effects on the normal shift control. On the other hand, when it is determined in step S7 that there is a possibility that air is mixed in, hydraulic control for discharging air is performed in step S9 and subsequent steps. In step S9, it is determined whether or not an execution permission condition for the air discharge control is satisfied.

For example, the following conditions (1) to (3) are determined as the execution permission conditions. (1) N first after the ignition switch is turned on
D range (drive range) switched from the range (neutral range). (2) Line pressure control (ND select control) performed at a predetermined time immediately after switching from the N range to the D range
Has been completed.

(3) The first speed is steady without any shift request. When the execution permission condition is satisfied, the process proceeds to step S10, and an air discharge control for forcibly supplying hydraulic pressure to the friction engagement element to be released at the current gear (first speed) is executed. Specifically, both the shift solenoid (A) 5 and the shift solenoid (B) 6 are periodically switched OFF.

At the first speed, the shift solenoid (A) 5
And the shift solenoid (B) 6 are both turned on, the high clutch H / C is released, and the low clutch L
/ C is engaged, the state where both the shift solenoid (A) 5 and the shift solenoid (B) 6 are OFF corresponds to the state of the third speed, and the low clutch L /
C and the high clutch H / C are engaged (see FIGS. 3 and 4).

Accordingly, by periodically switching both the shift solenoid (A) 5 and the shift solenoid (B) 6 to OFF, the high clutch H / C to be released at the first speed
The supply of the hydraulic pressure is periodically repeated for the high clutch H / C, and the air mixed in the hydraulic circuit of the high clutch H / C is discharged by the supply of the hydraulic pressure. In step S11, it is determined whether or not the execution time of the air discharge control has reached a predetermined time, and the process returns to step S9 until the predetermined time has been reached.
Proceeding to 12, the completion of the air discharge control is determined, and this program is ended.

Step S6 is omitted, and depending on whether the temperature has dropped to the reference temperature, the engine 1
A configuration may be adopted in which only the entry of air into the hydraulic circuit during the stop is determined. FIG. 6 is a flowchart showing a second embodiment of the air discharge control. Step S
At 21, ON / OFF of the ignition switch 20
Is determined.

When the ignition switch 20 is OFF, the process proceeds to step S22, and it is determined whether or not the first time of switching from ON to OFF. If it is the first time, the process proceeds to step S23, and the value of the timer timer is set to 0
Reset to. If it is not the first time, step S24
Then, the value of the timer timer is counted up in each execution cycle of the program executed every predetermined time, with the result of adding 1 to the previous value of the timer timer as the current value.

Thus, the timer timer measures the time elapsed since the ignition switch 20 was turned off. If it is determined in step S21 that the ignition switch 20 is ON, the process proceeds to step S25, where the value of the timer timer is compared with a reference time TIM.

Since the timer timer measures the elapsed time since the ignition switch 20 was turned off, in step S25, the ignition switch 20 is turned off.
Is turned off. When it is determined in step S25 that the value of the timer timer exceeds the reference time TIM, the process proceeds to step S27, and it is estimated that air is mixed in the hydraulic circuit.

The value of the timer timer is equal to the reference time TIM.
Is determined to be longer than the predetermined time, in other words, the time during which the engine 1 is stopped, in other words, the time during which the supply of hydraulic pressure to the hydraulic circuit is stopped is longer than a predetermined time, and during this time, the air to the hydraulic circuit is Is presumed to be mixed. On the other hand, when it is determined in step S25 that the value of the timer timer is equal to or less than the reference time TIM, the process proceeds to step S26.

In step S26, it is determined whether the air discharge control was performed during the previous operation and whether the air discharge control was performed only for a predetermined period. The timer ti
When it is determined that the value of mer is equal to or less than the reference time TIM, the time during which the engine 1 is stopped, in other words, the time during which the supply of hydraulic pressure to the hydraulic circuit is stopped is short, and It is estimated that there is no air mixing. However, if the air discharge control has not been completed during the previous operation, there is a possibility that there is air remaining without being discharged, and the process proceeds to step S27.

On the other hand, if it is determined in step S26 that the air discharge control has been completed during the previous operation,
Since it is determined that there is no air that has stopped and no air remains without being discharged, the process proceeds to step S28, where it is determined that no air has been mixed, and the program ends. If it is determined in step S27 that air is mixed in the hydraulic circuit, it is determined in step S29 whether the execution permission condition of the air discharge control is satisfied, as in step S9.

When the execution permission condition is satisfied, step S3
0, and executes air discharge control for forcibly supplying oil pressure to the friction engagement element (high clutch H / C) to be released at the current gear (first speed), as in step S10. I do. In step S31, it is determined whether or not the execution time of the air discharge control has reached a predetermined time, and the flow returns to step S29 until the predetermined time has been reached. It is determined that the discharge control is completed, and the program ends.

In the second embodiment, the determination in step S26 may be omitted.

[Brief description of the drawings]

FIG. 1 is a system diagram showing a vehicle drive system according to an embodiment.

FIG. 2 is a skeleton diagram showing a transmission mechanism in the embodiment.

FIG. 3 is a diagram showing combinations of engagement states of frictional engagement elements at each shift speed in the embodiment.

FIG. 4 is a diagram showing a combination of ON and OFF of shift solenoids A and B at each shift speed in the embodiment.

FIG. 5 is a flowchart illustrating a first embodiment of air discharge control.

FIG. 6 is a flowchart illustrating a second embodiment of air discharge control.

[Description of Signs] 1 ... Engine 2 ... Torque converter 3 ... Automatic transmission 4 ... Control valve 5 ... Shift solenoid (A) 6 ... Shift solenoid (B) 7 ... Line pressure solenoid 11 ... A / T controller 12 ... ATF temperature Sensor 13 Throttle opening sensor 14 Vehicle speed sensor 15 Engine rotation sensor 16 Inhibitor switch 17 Water temperature sensor 18 Outdoor temperature sensor 19 Oil temperature sensor 20 Ignition switch 21 Oil pump G1, G2 Planetary gear H / C ... High clutch R / C ... Reverse clutch L / C ... Low clutch 2 & 4 / B ... Brake band L & R / B ... Low & reverse brake L / OWC ... One-way clutch

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI theme coat ゛ (reference) F16H 59:78 F16H 59:78 63:12 63:12 F term (reference) 3J552 MA02 MA12 NA01 NB01 PA02 RA27 RA29 RC03 SA07 TB02 VA48W VA62Z VA74W VA76W VA76Y VB01Z VC01Z VC03Z VC07W VD18W VE01W

Claims (7)

[Claims] A hydraulic pressure is forcibly supplied to a frictional engagement element to be released at a current shift speed during non-shifting,
In a hydraulic control device for an automatic transmission that discharges air mixed in a hydraulic circuit, a stop period of hydraulic pressure supply to the hydraulic circuit is determined, and only when the stop period exceeds a predetermined period, the air discharge is performed. A hydraulic control device for an automatic transmission, characterized in that a forced hydraulic supply is performed. 2. Forcibly supplying hydraulic pressure to a frictional engagement element to be released at a current shift speed during non-shifting,
A hydraulic control device for an automatic transmission for discharging air mixed in a hydraulic circuit, wherein the air or the automatic transmission is started only when the temperature of the engine or the automatic transmission at the time of starting the engine combined with the automatic transmission falls below a reference temperature. A hydraulic control device for an automatic transmission, wherein a forced hydraulic supply for discharging is performed. 3. The hydraulic control device for an automatic transmission according to claim 2, wherein a temperature of a cooling water of the engine is determined as a parameter representing the temperature of the engine. 4. The hydraulic control apparatus for an automatic transmission according to claim 2, wherein the temperature of the hydraulic oil of the automatic transmission is determined as a parameter representing the temperature of the automatic transmission. 5. The hydraulic control device for an automatic transmission according to claim 2, wherein the reference temperature is changed to be lower as the outside air temperature is lower. 6. A hydraulic pressure is forcibly supplied to a friction engagement element to be released at a current shift speed during non-shifting,
In a hydraulic control device for an automatic transmission for discharging air mixed in a hydraulic circuit, a forced hydraulic supply for discharging the air is performed only when a stop time of an engine combined with the automatic transmission exceeds a reference time. A hydraulic control device for an automatic transmission, characterized in that the control is performed. 7. When the engine is started, it is determined whether or not the air discharge control has been completed during the previous operation. If not, the air discharge control is prioritized over the determination of the temperature or the stop time. The hydraulic pressure control device for an automatic transmission according to any one of claims 2 to 6, wherein the hydraulic pressure control device is configured to perform forced hydraulic pressure supply for the automatic transmission.