JPS61153045A - Control method of hydraulic control device for car - Google Patents

Abstract

PURPOSE:To improve speed change responsiveness by suddenly lowering the back pressure of an accumulator in an oil path put in the release condition at the time of down-shift on judging that it is down-shift and a driver demands sudden acceleration. CONSTITUTION:A hydraulic control device of an automatic transmission gear includes a duty ratio valve for reducing line pressure depending upon ON-OFF time ratio of a solenoid valve S4 controlled by ECU, a pressure regulating valve 400, an accumulator 500 disposed in an oil path between a shift valve and a brake B2 for controlling transient characteristic of oil pressure to the brake B2 and an accumulator 600 disposed in an oil path to a clutch C2. In this case, when down-shift is detected and sudden acceleration is demanded, that is, a throttle opening is more than a set value, the solenoid valve S4 is turned on. Thus, after the back pressure PA of the accumulator 500 is suddenly lowered, and the oil pressure of the brake B2 is suddenly lowered, a speed change command is output.

Description

[Detailed description of the invention]

[Industrial Application Field 1] The present invention relates to a control method for a vehicle hydraulic control device, and particularly to a control method for a vehicle hydraulic control device that improves the shift characteristics during downshifting with the accelerator depressed. Regarding improvements. [Prior Art] Equipped with a gear transmission mechanism and multiple frictional engagement devices, and hydraulically controlled! An automatic transmission for a vehicle configured to selectively switch the coupling of the frictional engagement device to achieve one of a plurality of gears by operating the D device is already widely known. There is. The frictional engagement device generally includes two sets of friction plate elements that are supported so as to be rotatable relative to each other, and a hydraulic servo device that drives the friction plate elements, and hydraulic pressure is supplied to the hydraulic servo device. Then, the two sets of friction plate elements are strongly pressed against each other, and are coupled in a relationship that allows torque transmission between them. The hydraulic control device for operating this friction coupling device generally includes a hydraulic power source including an oil pump, a primary regulator valve for regulating the base hydraulic pressure supplied from the hydraulic power source and generating line hydraulic pressure, a plurality of hydraulic control devices 11 for switching the supply of hydraulic pressure to the plurality of frictional engagement devices according to the operating state of the vehicle; Hydraulic pressure is supplied to a predetermined hydraulic servo device of the engagement device, or the supplied hydraulic pressure is cut off. Conventionally, line oil pressure has generally been used as the working oil pressure for such a III joint device. This line oil pressure is based on the basic oil pressure generated by the oil pump, which is automatically adjusted based on the vehicle speed and engine load (throttle opening) by the primary regulator valve.
It is obtained as a result of adjusting the pressure to a level that is compatible with The pressure is controlled to obtain the required pressure in all conditions including However, if line hydraulic pressure is directly supplied to the m-friction engagement device during gear shifting, there is a problem in that the friction plate element 2@ is suddenly pressed and the shift shock increases due to sudden changes in torque transmission. , this kind of automatic transmission hydraulic control! In the Il device, a 7-cumulator with a cylinder-piston structure is connected in the middle of an oil path that supplies and discharges hydraulic pressure to and from the frictional engagement device, and when supplying and discharging hydraulic pressure to and from the frictional engagement device, the rise and fall of the hydraulic pressure is controlled. We are trying to control the characteristics over time. (Problem to be solved by the invention) However, in a vehicle using a hydraulic control device equipped with an accumulator, power-on downshift (downshift with the accelerator depressed)
There is a problem in that the start of gear shifting is sometimes delayed. This is because the oil pressure at the time of return of the accumulator is high while the working oil pressure of the II friction engagement device on the high gear side is being released, and the oil pressure is high for a long time, so the accumulator remains in the high gear side until it completes its return. This is because the engaged frictional engagement device does not release the engagement of the two sets of friction plate elements. Originally, this type of 7-cumulator setting was normally set with the primary purpose of obtaining good shifting characteristics during power-on upshifts (upshifts with the accelerator depressed), and the release In many cases, the characteristics of time are not particularly taken into account. Of course, taking into consideration the characteristics at the time of release, an orifice or other part was added in the oil path to immerse the friction plate element of the friction engagement device even in the middle of release, thereby suppressing a sudden drop in output shaft torque. However, the reality is that the effect is limited to areas where the accelerator depression amount or accelerator depression speed is relatively small, and almost no effect can be obtained when the accelerator depression amount is large or the accelerator depression speed is high. It is. Further, when such control is performed, although the effect of reducing shift shock can be obtained to some extent, there is a problem in that the time required for shifting becomes longer and responsiveness is rather deteriorated. In particular, in the combination of a turbocharged engine and an automatic transmission, the engine itself has a problem called turbo lag, which makes the poor response particularly noticeable when accelerating suddenly from low rpm. There's a problem.

[Purpose of the invention]

The first invention has been made in view of such conventional problems, and it is an object of the present invention to improve the responsiveness of gear shifting during power-on downshifting when it is determined that the driver is requesting sudden acceleration. An object of the present invention is to provide a control method for a vehicle hydraulic control device that can perform the following steps. Further, the second invention similarly improves the responsiveness of the gear shift during a power-on downshift when the driver is thought to be requesting sudden acceleration, and also improves the responsiveness of the shift when the driver is considered to be requesting sudden acceleration. output fluctuation during gear shifting (
An object of the present invention is to provide a control method for a vehicle hydraulic control device that can reduce gear shift shock.

[Means to solve the problem]

As shown in FIGS. 1A and 1B, the first invention includes a friction engagement device for controlling a gear transmission mechanism, and a friction engagement device that switches the engagement state of the friction engagement 1. and an accumulator with a back pressure chamber provided in an oil passage between the friction engagement device and the hydraulic control equipment to control hydraulic transient characteristics in the oil passage. A method for controlling a hydraulic control device for a vehicle includes a procedure for detecting whether or not a downshift is being performed, a procedure for detecting at least one of an accelerator depression speed and an accelerator opening degree, and a procedure for detecting at least one of an accelerator depression speed and an accelerator opening degree when a downshift is being performed. When at least one of the openings exceeds a predetermined value, the back pressure of the accumulator located in the oil passage to the frictional engagement device that is in a released state during the downshift is suddenly reduced. The above objective is achieved by including the following steps. Further, the second invention, as summarized in FIGS. 2(A) and 2(B), includes a friction engagement device for controlling a gear transmission mechanism and switching the engagement state of the friction engagement device. and an accumulator with a back pressure chamber provided in an oil passage between the friction engagement device and the hydraulic control equipment to control hydraulic transient characteristics in the oil passage. A control method for a vehicle hydraulic control device includes a procedure for detecting whether a downshift is being performed, a procedure for detecting at least one of an accelerator depression speed and an accelerator opening degree, and a procedure for detecting at least one of an accelerator depression speed and an accelerator opening degree when a downshift is being performed. When at least one of the degrees exceeds a specified value, the back pressure of the accumulator located in the oil passage to the frictional engagement device that is in the released state during the downshift is suddenly reduced; When downshifting and both the accelerator depression speed and accelerator opening detected in the above procedure (if only one is detected, the value) are within the specified values, the oil passage to the friction engagement device is closed. The above object is achieved by including a step of maintaining the back pressure of the accumulator in the oil passage which is in the released state in the downshift at a predetermined level at which the X engagement device slides away. It is something.

[Function] The first invention focuses on the fact that when a driver requests sudden acceleration, emphasis is placed on shift responsiveness rather than reducing shift shock, and the driver's The degree of demand for sudden acceleration is recognized by detecting at least one of accelerator depression speed and accelerator opening degree, and when the detected value exceeds a specified value, and when the driver requests sudden acceleration while downshifting. When it is determined that there is Because the friction plate element of the friction engagement device is rapidly released,
That's how quickly you can shift gears. Further, in the second invention, while performing the above-mentioned action, when it is determined that the driver does not require sudden acceleration, the Sta plate element of the frictional engagement device slides to reduce the back pressure of the accumulator. However, since the rIi friction plate elements are maintained at a predetermined level suitable for separation, the friction plate elements, which previously had been engaged for a long time and separated rapidly, are now separated while being slid appropriately. This further provides the effect of reducing gear shift shock. [Actual j] Hereinafter, based on the drawings, a hydraulic illumination system for a vehicle used to apply the present invention will be described in detail. FIG. 3 shows an overall outline of a vehicle automatic transmission employing the hydraulic control device. This automatic transmission includes, as its transmission section, a torque comparator 920, an overdrive mechanism 40, and an underdrive mechanism 60 with three forward speeds and one reverse speed. The torque converter 20 includes a pump 21 and a turbine 2.
2, a stator 23, and a lock-up clutch 24. The pump 21 is connected to the crankshaft 10 of the engine 1, and the turbine 22 is connected to a carrier 41 of a planetary gear system in an overdrive mechanism 40. In the overdrive mechanism 40, a planetary pinion 42 rotatably supported by the carrier 41 meshes with a sun gear 43 and a ring gear 44. Further, a clutch Co and a one-way clutch Fo are provided between the sun gear 43 and the carrier 41, and a brake So is provided between the sun gear 43 and the housing Hu.
is provided. The underdrive mechanism 60 is provided with two rows of planetary gears, one on the front side and the other on the rear side. This planetary gear system consists of a common sun gear 61, a ring gear 62, 63, a planetary pinion 64, 65, and a carrier 66, 67, respectively. A ring gear 44 of the overdrive mechanism 40 is connected to the ring gear 62 via a clutch C1. Further, a clutch C2 is provided between the ring gear 44 and the sun gear 61. Further, the carrier 66 is connected to the ring gear 63, and the carrier 66 and the ring gear 63 are connected to the output shaft 70. On the other hand, the carrier 67
A brake B3 and a one-way clutch F2 are provided between the housing 1-1u and the sun gear 61.
A brake B2 is provided between the sun gear 61 and the housing HU via a one-way clutch F1, and a brake B1 is provided between the sun gear 61 and the housing HU. This automatic transmission is equipped with a transmission section as described above, and receives signals from a throttle sensor 100 that detects the throttle opening that reflects the load condition of the engine 1, a vehicle speed sensor 102 that detects vehicle speed, etc. The processing device (ECIJ) 104 drives and controls the electromagnetic solenoid valves 81 to S4 in the hydraulic control bag @106 according to a preset shift pattern, and operates each clutch, brake, etc. as shown in FIG. A combination of engagements is performed to achieve speed change control. The II electromagnetic solenoid valves 1 and 82 control a shift valve for speed change, the electromagnetic solenoid valve S3 controls the lock-up clutch 24 of the torque converter 20, and the electromagnetic solenoid valve S4 controls a hydraulic control device. 106
The duty valves are controlled to adjust the back pressure of the accumulators inside. In Fig. 3, reference numeral 110 is a shift position sensor that detects the positions of N1D, R, etc. operated by the driver, and 112 is a pattern select switch that selects E (economical driving) and P (power driving). 114 is a water temperature sensor that detects the engine cooling water temperature, 116 is a foot brake, and 118 is a brake switch that detects the operation of a handbrake. Further, reference numeral 120 indicates an oil temperature sensor for detecting oil wetness of the engine, and reference numeral 122 indicates an intake temperature sensor for detecting the intake temperature of the engine. Next, FIG. 5 shows the main parts of the hydraulic control device 106. In the figure, reference numeral S4 denotes the electromagnetic solenoid valve 3, which is turned on and off at high speed according to instructions from the ECtJ104.
00 is a duty valve that reduces line pressure based on the ON/OFF time ratio of the electromagnetic solenoid valve S4, 40
0 is a pressure regulating valve that outputs the hydraulic pressure acting on the duty valve 300, and 500 is a pressure regulating valve provided in the oil path between the shift valve (not shown) and the brake B2 in order to control the transient characteristics of the hydraulic pressure to the brake B2. The accumulator 600 is also provided in the oil path to the clutch C2,
O8 indicates an oil strainer. About 2 electromagnetic solenoid valves S4 are equipped with drain boats 2o1. This electromagnetic solenoid valve S4 generates oil pressure in the oil passage 202 when turned ON by the output signal of the ECU 104, and drains the oil in the oil passage 202 from the drain boat 201 when turned OFF. The duty valve 300 has a face area A1~As
A spool 304 having lands 301 to 303 with <AI<A2-A3) is provided. Further, a first manual port 305 to which the line pressure PL is applied, a second manual port 306 to which the output hydraulic pressure P1 of the pressure regulating valve 400 is applied, and an output hydraulic pressure P1 from the pressure regulating valve 400 is inputted via the orifice 307. It also includes an output port 309 to the back pressure chamber 502, 602 of the accumulator 500, 600. The pressure regulating valve 400 is a well-known one, and includes a spool 4 having lands 401 and 402 with face areas B+ and B2.
03, and an input port 404 and an output port 405 to which line pressure PL is applied. Next, the basic operation of this hydraulic control device will be explained. The pressure regulating valve 400 is operated by the input boat 404 by a well-known function.
The line pressure PL applied to the line pressure PL is adjusted to a constant pressure P1 that is lower than the line pressure PL. This constant pressure P1 is set by a spring 406. This oil pressure P1 is applied to the duty valve 300
is applied to the second human-powered boat 306 , and is applied to the third human-powered boat 308 via the orifice 307 . Now, when the electromagnetic solenoid valve S4 is turned off by a command from the ECU 104, the oil in the oil passage 202 is drained from the drain boat 201, so the land 301
The spool 304 of the duty valve 300 is in the state on the left side of the figure due to the difference between the face areas A1 and A2 of the valves 302 and 302. Therefore, the line pressure PL applied to the first human-powered boat 305 is outputted as is from the output port 309. On the other hand, according to a command from the ECU 104, the electromagnetic solenoid valve S
When 4 is turned ON, the 11! Since the drain boat 201 of the solenoid valve S4 is closed, the orifice 30
7, the oil pressure P1 output from the output port 405 of the pressure regulating valve 400 is generated in the oil passage 202. As a result,
The spool 304 of the duty valve 300 is A3XP+
It receives an upward force equivalent to , resulting in the state on the right side of the diagram.
The output port 309 is closed, and the oil pressure after the output port decreases. Here, the electromagnetic solenoid valve S4 is turned on and off at high frequency.
By changing the ratio of ON and OFF during the cycle (duty ratio), the oil pressure P^ of the output port 309 can be arbitrarily set to a value corresponding to the ratio (duty I control). . Therefore, the electromagnetic solenoid valve S4 is controlled by the ECL1104.
By turning on and off and changing the duty ratio based on various conditions, the pressure P^ in the back pressure chamber of each accumulator can be freely controlled. On the other hand, the oil pressure PM of the frictional engagement device during operation of the accumulator 500 (or 600) can generally be expressed by the following equation. PM= (C+-02)PA/CI +Fs/C+...
・(1) Here, C1 is the accumulator piston 501 (or 6
01) large diameter side area, C2 is the accumulator piston 5
01 (or 601) small diameter side area. As is clear from this formula, the accumulator 500 (or 600)
11 during accumulator operation by controlling the back pressure P^ of The oil pressure PM of the frictional engagement device can be changed arbitrarily including a sudden drop. Further, in FIG. 4, only the accumulator 500 provided in the oil path to the brake B2 and the accumulator 600 provided in the oil path to the clutch C2 are shown as accumulators, but the duty valve 300 In addition to this, the output oil pressure P^ is also led to the back pressure of an accumulator provided in the oil path toward the brake B, ON clutch C+, clutch Go, etc. There are two types of electromagnetic solenoid valves: those that generate hydraulic pressure when in the ON state, and those that generate hydraulic pressure when in the OFF state.
Basically, both can be adopted, but in this embodiment, O
A device that generates hydraulic pressure in the N state is used. This is because if a disconnection occurs in the wiring that turns the electromagnetic solenoid valve ON and OFF, the spool 304 of the duty valve 300 will be in the state on the left side of the figure, and the output boat 30 will be in the state shown on the left side of the figure.
This is because line pressure PL is applied to line 9, which fixes it at a high level, which is advantageous in terms of fail-safety. Next, an embodiment of the second invention (including a part of the embodiment of the first invention) using the above hydraulic control device will be described in detail based on the flowchart shown in FIG. There are various patterns for power-on downshift.
Since the concept is similar, a case where a power-on downshift from 2nd speed to 1st speed is performed is taken as an example. In addition, in the figure, the king is a flag for setting the flow to the third level. The steps will be explained below. Since flag T is initially set to 0, step 70
1 to 702, and a shift determination is made in the same manner as in the past based on vehicle speed, throttle opening, etc. After this determination is made, in step 703 it is confirmed what type of shift determination was made. If it is confirmed in step 703 that the shift judgment is a downshift from 2nd speed to 1st speed, the process proceeds to step 704 where the throttle opening θ at that time is larger than the preset opening θ0. It is determined whether or not. When it is determined that the throttle opening θ is larger than the set opening θG, that is, when it is determined that the accelerator has been depressed more than a predetermined amount, it is determined that the driver is requesting sudden acceleration. Then, in step 705, the electromagnetic solenoid valve S4 is turned on, causing the back pressure P^ of the accumulator 500 to suddenly decrease, and the hydraulic pressure of the brake B2 to decrease suddenly. At this point, a shift command is issued in step 706. As a result, since the oil pressure of the brake B2 is already quite low, it is released in an extremely short time, and the shift from the second speed to the first speed is completed earlier. Note that the back pressure of the accumulator 500 that has been suddenly reduced is determined in step 707.
The pressure is maintained until it is determined that the elapsed time t from the shift determination is greater than the set timer T1, and as the timer time T elapses, the electromagnetic solenoid valve S4 is turned off in step 708, and the pressure is increased to the line pressure again. . That is, while the elapsed time t is smaller than the timer T1, the process proceeds to step 709, where the flag T is set to 1, which is then reset, and in the next flow, the process proceeds directly to immediately before step 707 via step 701, and in step 707. The determination is repeated repeatedly. Note that this flag T is reset to O in step 710. On the other hand, if it is determined in step 704 that the throttle opening θ is less than the set opening 00, step 711
Proceed to and control the electromagnetic solenoid valve S4 by duty,
The accumulator back pressure P^ is regulated to a predetermined value depending on the type of shift, throttle opening, etc., and then a shift command is issued in step 712. As a result, the oil pressure in the oil path connected to the brake B2 is adjusted to a value at which the friction plate element of the brake B2 is just released while slipping, and gear changes are performed smoothly without sudden changes in torque transmission. Note that the accumulator back pressure P^ maintained at a predetermined value by duty control is determined in step 71.
3, a predetermined setting timer T1' (generally T1-≧T
+) time has elapsed in step 714! ! The magnetic solenoid valve S4 is turned off and the line pressure is returned to PL. Note that step 716 is a step of resetting the flag T to 0. In addition, in the above flow, it is preferable that the set opening degree θ0 regarding the throttle opening degree θ is set depending on the type of speed change, the select position of the pattern select switch, and the like. In this case, for example, when the pattern select switch is set to the P (power) pattern, it is the time when quick response is required, so the E (economy) pattern is selected.
It is preferable that the control in steps 705 to 710 be performed from a time when the set opening degree is lower than when the pattern is set. Note that if steps 711 to 716 are bypassed as shown by broken lines, the flowchart in FIG. 6 corresponds to the first embodiment of the first invention. In this case, when the throttle opening θ is below the predetermined value θ0, no control is performed specifically to reduce shift shock, as in the past, but the control logic can be configured that much more simply. I can do it. Next, FIG. 7 shows a speed change characteristic diagram when the response is accelerated according to the flow shown in FIG. 6 when the throttle opening θ is larger than the set opening θ0. In the figure, the solid line is the conventional characteristic, and the broken line is the characteristic controlled by the flowchart. That is, conventionally, when the accelerator is first depressed at point A, a shift determination from second speed to first speed is issued at point B, and a shift command is issued at point 0. As a result, the hydraulic pressure 1 day 2 of the brake B2 begins to decrease from point D, which is slightly delayed due to the response delay of the electro-hydraulic system. Point E to point H is the return position (operating area) of the accumulator 500), and the point where the oil pressure P82 becomes Pe2-
Brake B2 begins to slip from this point. Furthermore, at five points where the oil pressure PB2 reaches Peoz°, the automatic transmission becomes completely neutral, so the engine rotational speed increases and the output shaft torque decreases to approximately zero. On the other hand, when the turbine speed reaches synchronous rotation at point L, the one-way clutch F2 is locked and the output shaft torque increases to the equivalent of the first speed. On the other hand, in the case of control according to the flowchart shown in FIG. 6, after determining the speed change at point B, it is determined that the accumulator back pressure P^ should be reduced, and the electromagnetic solenoid valve S4 is turned on to reduce the accumulator back pressure P^. In order to rapidly decrease the hydraulic pressure P of the brake B2 when the accumulator is at the return position ES-H.
82 is less than or equal to Psz-. The reason why Peo does not become less than 2° is due to the pressing force exerted by the return spring. Therefore, the brake B2 starts to cool down from point B, and the one-way clutch F2 locks at point G. As a result, the time delay equivalent to the difference ΔT between the G point and the L point can be improved. It should be noted that since the electromagnetic solenoid valve S4 is turned off after a certain period of time T1 (point K) corresponding to the end of the shift, the accumulator back pressure P^ is restored to the line pressure PL. Next, a second embodiment of the second invention will be described using the flowchart of FIG. The control according to this flowchart takes into consideration not only the amount of accelerator depression but also the accelerator depression speed. Compared to the flowchart of FIG. 5, steps 801 to 805 are added between steps 703 and 704. That is, steps 801 to 804 are steps for monitoring the data of the latest n1il throttle opening degree θ. That is, in step 801, the data of θi is sequentially transferred to the memory of the previous six times, and in step 802, 1
count. In step 803, 1 is n
This is repeated until 1 becomes equal to n, and at step 804, the currently monitored θ is stored in the θn memory. Then, in step 805, the θ
It is determined whether the change rate of the time Δt&l, which is the difference between n and the first 01, is equal to or greater than a predetermined constant value of 60. If it is, the process proceeds to step 704, and if it is less than that, the process proceeds to step 711. It is something that In this way, the reason why we took the latest n pieces of data and calculated the difference between the first and last data was because the time required for one flow of the computer is too short, so the difference in measured Fl of accelerator depression speed becomes large. This is because they were trying to prevent this. Note that this Δ[ is the elapsed time from the first sample time to the current sample time, and is a value obtained by registering the measurement time for each data sample and comparing the times. Time is approximately constant (Δt
o), it is also possible to approximate by ΔLoXn. This flowchart is the same as the flowchart of FIG. 6 above, except that the flag T is reset and 1 is set to 2 in step 710', so a redundant explanation will be omitted. According to the control shown in FIG. 8, the accelerator depression speed is taken into consideration in addition to the accelerator depression amount, and both of them are set to the specified value θ.
o1θ. When this is the case, the control in steps 705 to 710- for improving responsiveness is performed for the first time, and when even one of the values is less than the specified value, steps 711 to 716 for reducing the shift shock are executed. This allows control to be more responsive to the driver's senses than the control based on the flowchart of FIG. 6. In other words, if either the accelerator depression speed or the accelerator depression amount is less than the specified value, it cannot necessarily be assumed that the driver is requesting sudden acceleration, and rather than accelerating response, friction is caused in the accumulator operating region. This is because it is considered preferable to reduce the shift shock by letting the engagement device slide. In addition, when steps 711 to 716 are bypassed as shown by the broken line in FIG. 8, the flowchart in FIG. 8 becomes a flowchart corresponding to the second embodiment of the first invention. In this case, if at least one of the accelerator depression amount and the accelerator depression speed is less than the specified value, control to reduce the shift shock will not be performed as in the past, but the control logic will The advantage of being so simple is surprising. In addition, in the above embodiment, an example was shown in which it is determined whether to give priority to responsiveness or reduction of shift shock based on the amount of accelerator depression, or both the amount of accelerator depression and the speed of accelerator depression. In the present invention, it is also possible to classify the cases based only on the accelerator depression speed. Furthermore, in the second invention, as the accumulator backpressure adjusting means for reducing the shift shock, a method was adopted in which duty control was performed according to instructions from a computer using a high-speed electromagnetic solenoid. The back pressure control of the accumulator is not limited to this, for example, it may be controlled by an electromagnetic proportional valve that can increase or decrease the output hydraulic pressure according to the increase or decrease of the solenoid current according to instructions from a computer, or it may be controlled by an orifice etc. to control the pure hydraulic pressure. It may also be controlled by a circuit. Effects of the Invention As explained above, according to the first invention, during downshifting when the driver is considered to be requesting sudden acceleration, the release state is achieved by rapidly reducing the back pressure of the accumulator. It is possible to quickly release the frictional engagement device, and therefore, an excellent effect can be obtained in that the responsiveness of the speed change can be improved accordingly. According to the second invention, in addition to the above effects, when it is determined that the driver is not requesting sudden acceleration, the back pressure of the accumulator is released while the engaging device is just slipping. It is possible to adjust the oil pressure to such a level that the gear is released, thereby achieving the effect of being able to shift gears with less shock without sudden changes in torque.

[Brief explanation of drawings]

FIG. 1 (A>(B) is a flowchart showing the gist of the control method for a vehicle hydraulic control device according to the first invention, and FIG. 2 (A)
B) is a flowchart showing the gist of the second invention, FIG. 3 is an overall schematic diagram of an automatic transmission for a vehicle to which the present invention is applied, and FIG. 4 is a diagram showing a friction engagement device of the automatic transmission. FIG. 5 is a hydraulic circuit diagram showing the main parts of the hydraulic control device of the automatic transmission; FIG. 6 is a diagram showing the state of engagement and combination; FIG. (including the first embodiment of the first invention); FIG. 7 is a shift transient characteristic diagram when the above control flow is used; FIG. It is a flowchart which shows the control flow of an example (partly including the second embodiment of the first invention). 100... Throttle sensor, 102... Vehicle speed sensor, 112... Pattern select switch, 104...
ECU (computer), 500.600...Accumulator, 502.602...Back pressure chamber, S4...Electromagnetic solenoid valve, 300...Duty valve, 400...Pressure regulating valve.

Claims (2)

[Claims] (1) A friction engagement device for controlling a gear transmission mechanism,
a hydraulic control device for switching the engagement state of the frictional engagement device; and a hydraulic control device provided in an oil passage between the frictional engagement device and the hydraulic control device, for controlling hydraulic transient characteristics in the oil passage. An accumulator with a back pressure chamber, and a method for controlling a hydraulic control device for a vehicle, comprising: a procedure for detecting whether or not a downshift is being made; and at least one of an accelerator depression speed and an accelerator opening degree.
a procedure for detecting a release state in the oil path to the frictional engagement device during a downshift and when at least one of the accelerator depression speed and the accelerator opening exceeds a specified value; A method of controlling a hydraulic control device for a vehicle, comprising: rapidly reducing the back pressure of the accumulator located in the oil passage. (2) a friction engagement device for controlling the gear transmission mechanism;
a hydraulic control device for switching the engagement state of the frictional engagement device; and a hydraulic control device provided in an oil passage between the frictional engagement device and the hydraulic control device, for controlling hydraulic transient characteristics in the oil passage. An accumulator with a back pressure chamber, and a method for controlling a hydraulic control device for a vehicle, comprising: a procedure for detecting whether or not a downshift is being made; and at least one of an accelerator depression speed and an accelerator opening degree.
and when at least one of the accelerator depression speed and the accelerator opening exceeds a specified value during a downshift, the oil path to the frictional engagement device is in a release state during the downshift. The back pressure of the accumulator located in the oil path is suddenly reduced, and both the accelerator depression speed and accelerator opening degree detected in the above procedure during downshift (if only one is detected, the value) are within the specified value. , the back pressure of the accumulator in the oil path to the frictional engagement device that is in the release state in the downshift is reduced to a predetermined level at which the frictional engagement device slides away. A method for controlling a hydraulic control device for a vehicle, comprising: a procedure for maintaining a hydraulic control device for a vehicle.