JP3645649B2 - Line pressure control device for automatic transmission - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a line pressure control device for an automatic transmission that variably sets an automatic transmission line pressure in accordance with the temperature of an automatic transmission oil (ATF), a shift operation, and the like.
[0002]
[Prior art]
Conventionally, in an automatic transmission, oil discharged from an oil pump is regulated to an optimum line pressure according to the operating state by a pressure regulator valve, and this line pressure is used as an operating pressure to each shift clutch or brake for shifting. In addition to supplying the hydraulic pressure, the hydraulic pressure based on the line pressure is also supplied to each solenoid valve and the like in order to appropriately perform these operating pressures.
[0003]
The shift control of the automatic transmission is performed by switching the shift valves interposed in the line pressure passages for supplying the line pressure to the shift clutches and brakes. The transmission control device sets the transmission characteristics with reference to the transmission characteristics set in advance based on the throttle opening and the like, and is controlled by the transmission control signal.
[0004]
An orifice is interposed in each line pressure passage that communicates each shift clutch and brake with each shift valve, and the shift clutch is engaged by the line pressure when the shift stage is switched by the shift valve. A shock (so-called shift shock) is prevented by gently increasing the line pressure by the orifice.
[0005]
However, for example, when starting from a state left in a cold region, the oil for automatic transmission (hereinafter referred to as ATF) is in a low temperature state, and thus has a high viscosity. Therefore, the flow resistance of the entire hydraulic circuit increases, and the engine starts. Thereafter, even if the oil pump tries to supply the ATF to the line pressure passage, the flow resistance causes a delay in the line pressure supplied to the transmission clutches and brakes, and after starting, the range lever position of the select lever is set to N (neutral). ) A response delay is likely to occur in the shift operation to each gear stage by the select lever operation from the range or P (barking) range to the D (drive) range or R (reverse) range, or automatic shift after operating the D range. There was a problem of becoming.
[0006]
Therefore, for example, as disclosed in JP-A-61-127955 or JP-A-1-307552, when the ATF temperature is lower than the set value, the line pressure is set higher than normal, A technique for compensating for a response delay by increasing the flow rate of ATF is known.
[0007]
[Problems to be solved by the invention]
However, the response delay described above is caused by the fact that the ATF escapes from the line pressure passage to the oil tank when the engine is stopped for a while rather than the flow path resistance due to the orifice, and the oil pump is driven when the engine is started. There is a delay before the ATF is filled into the pressure passage, which is considered to be a major factor. That is, after the ATF is once filled in the control oil passage such as the line pressure passage and each valve and the line pressure rises to a predetermined pressure, the line pressure is released even if the ATF temperature is low and the viscosity is high. It is thought that the device itself becomes small and maintains almost the same state as the ATF at normal temperature. Therefore, after the engine is started, after the line pressure filled in the line pressure passage rises to a predetermined pressure, the response delay is unlikely to occur when the shift operation is performed by the select lever operation or automatic shift. In the prior art, even when the line pressure is sufficiently filled in the line pressure passage, control is performed to set the line pressure uniformly high while the ATF temperature is low. There is an inconvenience that the clutch engagement force for the brake becomes stronger than necessary, and so-called shift shock is increased.
[0008]
In view of the above circumstances, the present invention prevents the delay in response at the time of shifting when the ATF temperature is low, and also reduces the so-called shift shock caused by setting the line pressure high. An object is to provide a control device.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, an automatic transmission line pressure control apparatus according to a first aspect of the present invention comprises an oil temperature determining means for detecting a variable relating to the oil temperature of the automatic transmission line pressure and comparing the variable with a low temperature determination value. A lever operation determining means for determining whether the select lever is in an initial set state, and a first control in which the line pressure is higher than a normal control oil pressure when the variable is equal to or lower than the low temperature determination value and the select lever is in the initial set state. A second control hydraulic pressure that is higher than the normal control hydraulic pressure and lower than the first control hydraulic pressure when the variable is less than the low temperature determination value and the select lever is set to the travel range. And a line pressure setting means for setting the line pressure to a normal control oil pressure when the variable is higher than the low temperature determination value.
[0010]
According to a second aspect of the present invention, there is provided an automatic transmission line pressure control device that detects an oil temperature variable of an automatic transmission line pressure, compares the variable with a low temperature determination value, and an initial set of a select lever. A lever operation determining means for determining whether the state is the state, a duration determining means for measuring the duration of the initial setting state of the select lever and comparing the duration with the set time, and the variable is equal to or lower than the low temperature determination value. When the duration is within the set time, the line pressure is set to a first control oil pressure that is higher than the normal control oil pressure, the variable is not more than the low temperature judgment value, and the select lever is set to the travel range. Alternatively, when the variable is equal to or lower than the low temperature determination value and the duration has reached the set time, the line pressure is set to a second control pressure that is higher than the normal control hydraulic pressure and lower than the first control hydraulic pressure. Set the hydraulic, also when the variable is greater than the low temperature determination value is characterized by having a line pressure setting means for setting the line pressure to the normal control pressure.
[0011]
According to a third aspect of the present invention, there is provided an automatic transmission line pressure control device for detecting a variable relating to an oil temperature of an automatic transmission line pressure and comparing the variable with a low temperature determination value, and a shift of the automatic transmission. Shift operation determining means for determining whether the gear is in an initial state; and when the variable is equal to or lower than the low temperature determination value and the gear is in the initial state, the line pressure is set to a first control oil pressure that is higher than the normal control oil pressure. The second control hydraulic pressure is higher than the normal control hydraulic pressure and lower than the first control hydraulic pressure when the variable is equal to or lower than the low temperature determination value and the shift stage of the automatic transmission is shifted from the initial state. And a line pressure setting means for setting the line pressure to a normal control oil pressure when the variable is higher than the low temperature determination value.
[0012]
According to a fourth aspect of the present invention, there is provided a line pressure control device for an automatic transmission that detects a variable relating to an oil temperature of an automatic transmission line pressure, compares the variable with a low temperature determination value, and shifts the automatic transmission. A shift operation determining means for determining whether the gear is in an initial state, a duration determining means for measuring the duration of the initial state of the gear and comparing the duration with a set time; and the variable is the low temperature determination value. If the duration is within the set time, the line pressure is set to a first control oil pressure that is higher than the normal control oil pressure, the variable is less than the low-temperature determination value, and the automatic transmission shifts from the initial state. When the operation is performed, or when the variable is equal to or lower than the low temperature determination value and the duration has reached the set time, the line pressure is set to a second control hydraulic pressure that is higher than the normal control hydraulic pressure and lower than the first control hydraulic pressure. Set and above When the number is higher than the low temperature determination value is characterized by having a line pressure setting means for setting the line pressure to the normal control pressure.
[0013]
In the automatic transmission line pressure control device according to the first aspect of the present invention, when the variable related to the oil temperature of the automatic transmission line pressure is lower than the low temperature judgment value, the automatic transmission oil (ATF) is low temperature and has high viscosity. Therefore, the line pressure is set to a first control oil pressure higher than the normal control oil pressure, the line pressure is quickly filled into the line pressure passage, and the select lever is moved to a travel range such as the D range or the R range. Response delay when set to. Then, when the select lever is set from the initial set state to the travel range, the line pressure is set to a second control oil pressure that is higher than the normal control oil pressure and lower than the first control oil pressure. A shock (so-called shift shock) when the shift clutch is engaged by the line pressure is reduced. When the variable is higher than the low temperature determination value, the line pressure is set to the normal control oil pressure.
[0014]
In the automatic transmission line pressure control device according to the second aspect of the present invention, when the variable related to the oil temperature of the automatic transmission line pressure is lower than the low temperature judgment value, the automatic transmission oil (ATF) is low temperature and has high viscosity. Therefore, when the above line pressure is the first control oil pressure higher than the normal control oil pressure, the line pressure is quickly filled into the line pressure passage, and the select lever is set to the travel range such as D range or R range. Prevent response delays. And when the select lever is set from the initial set state to the travel range, or when the duration of the initial set state is longer than the set time, that is, when the line pressure is sufficiently filled in the line pressure passage, By setting the line pressure to a second control oil pressure that is higher than the normal control oil pressure and lower than the first control oil pressure, a shock when the shift clutch is engaged by the subsequent line pressure (so-called shift shock) To ease. When the variable is higher than the low temperature judgment value, the line pressure is set to the normal control oil pressure.
[0015]
In the automatic transmission line pressure control device according to the third aspect of the invention, when the variable of the oil temperature of the automatic transmission line pressure is lower than the low temperature judgment value, the automatic transmission oil (ATF) is low temperature and has high viscosity. Therefore, the line pressure is set to the first control oil pressure higher than the normal control oil pressure, the line pressure is quickly filled into the line pressure passage, and the response delay when the shift stage of the automatic transmission is shifted from the initial state. To prevent. When the gear position is shifted from the initial state, the line pressure is set to a second control oil pressure that is higher than the normal control oil pressure and lower than the first control oil pressure. Reduces shock (so-called shift shock) when engaging the shift clutch. When the variable is higher than the low temperature judgment value, the line pressure is set to the normal control oil pressure.
[0016]
In the automatic transmission line pressure control device according to the fourth aspect of the present invention, when the variable related to the oil temperature of the automatic transmission line pressure is lower than the low temperature judgment value, the automatic transmission oil (ATF) is low temperature and has high viscosity. Therefore, the line pressure is set to the first control oil pressure higher than the normal control oil pressure, the line pressure is quickly filled into the line pressure passage, and the response delay when the shift stage of the automatic transmission is shifted from the initial state. To prevent. When the gear is shifted from the initial state, or when the duration of the initial state of the gear is longer than a set time, that is, when the line pressure is sufficiently filled in the line pressure passage, the line By setting the pressure to a second control hydraulic pressure that is higher than the normal control hydraulic pressure and lower than the first control hydraulic pressure, the shock (the so-called shift shock) that occurs when the shift clutch is engaged by the subsequent line pressure is alleviated. To do. When the variable is higher than the low temperature judgment value, the line pressure is set to the normal control oil pressure.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the drawings. 1 to 5 show a first embodiment of the present invention.
[0018]
Reference numeral 1 in FIG. 5 denotes a line pressure passage, which pumps up oil for automatic transmission (hereinafter referred to as “ATF”) stored in the oil tank 2 by the oil pump 3 and lines it to the clutch piston 4a provided in each shift clutch 4 and the like. Supply as pressure.
[0019]
In the line pressure passage 1, a pressure regulator valve 5 for adjusting the ATF discharged from the oil pump 3 from the upstream side to an optimum line pressure according to the operating state, a range position set by a select lever, that is, P Line pressure communicating with each range position according to each set position such as (parking) range, R (reverse) range, N (neutral) range, D (drive) range, 3rd speed range, 2nd speed range, 1st speed range, etc. A manual valve 6 for delivering the line pressure to the passage and a shift valve 7 for automatically shifting the gear stage according to the operating state are interposed, and a branch passage 1a is communicated from the shift valve 7 for each gear stage. The shift pressure of the shift valve 7 selectively connects the line pressure to the shift clutches 4 and the like. There performs shift control to block.
[0020]
Further, an orifice 9 that gently raises the line pressure for energizing the speed change clutch 4a is interposed in the middle of each branch path 1a. Further, the speed change clutch 4a is connected to a bypass path 1b that bypasses the orifice 9. When the line pressure is reduced, a check valve 10 that immediately returns ATF in the direction of the shift valve 7 is interposed, and an accumulator 11 that reduces the shift shock is connected downstream of the orifice 9 in each branch passage 1a. ing.
[0021]
Reference numeral 12 denotes a signal pressure passage, the upstream is connected to the discharge side of the oil pump 3 via a pilot valve (not shown), the downstream is bifurcated, and one branch passage is the shift valve 7. The other branch passage communicates with the back pressure side of the pressure regulator valve 5 through the orifice 13 and communicates with the back pressure side of each accumulator 11 through the accumulator control valve 14. Yes.
[0022]
A drain passage 12a communicates with the signal pressure passage 12 in the vicinity of the shift valve 7, and a shift solenoid 15 for controlling the flow rate of the drain passage 12a and setting a pilot pressure for the shift valve 7 is disposed in the drain passage 12a. Has been. Further, a drain passage 12b communicates with the signal pressure passage 12 downstream of the orifice 13, and a line pressure control valve for controlling the flow rate of the drain passage 12b to set the throttle pressure for the pressure regulator valve 5 in the drain passage 12b. 16 is disposed.
[0023]
Reference numeral 17 denotes a transmission control unit (TCU), which outputs a drive signal to the shift control valve 15 and the line pressure control valve 16 based on parameters representing operating conditions such as vehicle speed and throttle opening. The opening degree of each control valve 15, 16 is controlled stepwise to set the pilot pressure for the shift valve 7 and the throttle pressure for the brake regulator valve 5.
[0024]
The shift valve 7 automatically shifts or selectively cuts off the branch passage communicating with the speed change piston 4a of each speed change clutch 4 in accordance with the input pilot pressure. On the other hand, the pressure regulator valve 5 optimally adjusts the line pressure from the oil pump 3 according to the operating state in accordance with the throttle pressure.
[0025]
FIG. 4 shows a circuit configuration of the TCU 17. The TCU 17 is mainly composed of a microcomputer that connects the CPU 21, ROM 22, RAM 23, backup RAM 24, and I / O interface 25 to each other via a bus line, and in addition, signals from the output port of the I / O interface 25. Peripheral devices such as a drive circuit 26 that drives actuators, an A / D converter 27 that converts analog signals from sensors into digital signals, and a constant voltage circuit 28 that supplies a stabilized voltage to each part are incorporated. Yes.
[0026]
The constant voltage circuit 28 is connected to a battery 30 via a relay contact of a TCU relay 29. A relay coil of the TCU relay 29 is connected to an ignition switch 31 connected to the battery 30. The ignition switch When 31 is turned ON, the relay contact of the TCU relay 29 is closed, and a stabilized voltage is supplied to each part of the TCU 17 via the constant voltage circuit 28. The backup RAM 24 is always supplied with a backup voltage via the constant voltage circuit 28. The input port of the I / O interface 25 is connected to an idle switch 37 that is turned on when the accelerator pedal is released, a vehicle speed sensor 32, and an inhibitor switch 33 that detects a range position of a select lever (not shown). An engine speed signal calculated based on an output interval time such as a crank pulse in an engine control device (not shown) is input. In the TCU 17, a parameter that is a function of the engine speed, such as a crank pulse, may be directly input separately from the engine control device to calculate the engine speed. Further, at the input port of the I / O interface, the temperature of the ATF stored in the oil tank 2, which is a representative variable related to the oil temperature of the throttle opening sensor 34 and the line pressure, via the A / D converter 27. An ATF temperature sensor 35 (or an engine coolant temperature sensor 36) is connected.
[0027]
As shown in FIG. 1, the TCU 17 is provided with ATF temperature detection means 41, ATF temperature determination means 42, lever operation determination means 43, duration determination means 44, and line pressure setting means 45 as a line pressure control function. ing. The ATF temperature detection means 41 detects the ATF temperature TATF based on the output signal from the ATF temperature sensor 35, and the ATF temperature determination means 42 compares the ATF temperature TATF with a preset low temperature determination value TG to compare the ATF temperature ATF. It is determined whether or not is in a low temperature state. In the lever operation determining means 43, the select lever is in the initial set state, that is, the P (parking) range or N (neutral) range, which is the range position at the start, based on the range signal output from the inhibitor switch 33. Determine if there is.
[0028]
Further, the duration determination means 45 measures the duration time when the select lever 33 is in the initial set state after the ignition switch 31 is turned on or after the engine is started, and calculates the duration time and the set time tO. Compare. This set time tO is a sufficient time required for the ATF sucked up from the oil tank 2 by the oil pump 3 to be filled into the respective transmission clutches 4 via the line pressure passage 1, and is obtained in advance from experiments or the like.
[0029]
The line pressure setting means 45 sets the line pressure P for the clutch piston 4a of the transmission clutch 4 based on the determination results of the ATF temperature determination means 42, the lever operation determination means 43, and the duration determination means 44.
[0030]
Specifically, the line pressure P is set according to the line pressure setting routine shown in FIG. This line pressure setting routine is executed at predetermined intervals after the ignition switch 31 is turned on. First, in step S1, the current ATF temperature TATF is compared with the low temperature determination value TG to determine whether the ATF is in a low oil temperature state. Then, when the ATF temperature TATF is lower than the low temperature determination value TG (TATF <TG), the process proceeds to step S2, and when the ATF temperature TATF is equal to or higher than the low temperature determination value TG (TATF ≧ TG), the process proceeds to step S6. Branch to
[0031]
Then, when the process proceeds to step S2, it is determined based on the range signal from the inhibitor switch 33 whether or not the range position of the select lever is in the initial set state, that is, the start position, and the P range, N range, etc. When the initial set state is set, the process proceeds to step S3. When the travel range such as the D range, R range, or 1st to 3rd speed range is set from the initial set state, the process proceeds to step S5.
[0032]
When the select lever maintains the initial set state and the process proceeds from step S2 to step S3, the elapsed time time after the ignition switch 31 is turned on or after the engine is started is compared with the set time tO. And when sufficient time has not passed to fill the line pressure passage 1 by the oil / oil pump 3 driven by the engine start when the ATF that has been released from the line pressure passage 1 when left after the engine is stopped when time <t0. Advances to step S4, and sets the duty ratio DUTY of the drive pulse for the line pressure control valve 16 to the first set value A (see FIG. 3) which is the maximum value.
[0033]
Further, when branching from step S2 or step S3 to step S5, the duty ratio DUTY is set to a second set value B (see FIG. 3) lower than the first set value A and higher than the normal set value C. Then, the process proceeds to step S57.
[0034]
On the other hand, when the ATF temperature TATF is equal to or higher than the low temperature determination value TG (TATF ≧ TG) and the process proceeds from step S1 to step S6, the duty ratio DUTY is set to the normal set value A (see FIG. 3), and step S57. Proceed to
[0035]
In step S7, the duty ratio DUTY set in step S4, step S5, or step S6 is set, and the routine is exited.
[0036]
Then, a drive pulse corresponding to a pulse width modulation signal having a predetermined duty ratio DUTY is output from the drive circuit 26 of the TCU 17 shown in FIG. 4 to the line pressure control valve 16, and the valve opening degree of the line pressure control valve 16 is determined. Under the control, the throttle pressure for the pressure regulator 5 is set. When the duty ratio DUTY is the first set value A set in step S4, the line pressure P regulated by the pressure regulator 5 becomes the first control hydraulic pressure PH1 that is the maximum control pressure, and the line pressure passage 1 is quickly filled with ATF. When the duty ratio DUTY is the second set value B set in step S5, the line pressure P regulated by the pressure regulator 5 becomes the second control hydraulic pressure PH2 that is an intermediate pressure, and the select lever Shift shock is reduced when is set to the travel range.
[0037]
As described above, according to the first embodiment, when the ATF temperature TATF is low, the ignition switch 31 is turned on, the set time tO after the engine is started, or the set time tO is selected. By setting the line pressure P to the maximum control pressure until the lever is set to the travel range such as the D range or the R range from the initial set state, the above line pressure can be obtained even at low temperatures when the ATF becomes highly viscous. The ATF can be quickly filled into the passage 1 against the flow resistance by the orifice 9. As a result, the rise of the line pressure becomes faster, and the response delay when the select lever is switched to the travel range is eliminated. Further, after the set time tO has elapsed or when the select lever is switched to the travel range within the set time tO, the second control oil pressure is lower than the first control oil pressure PH1 and higher than the normal control oil pressure P0. By setting to PH2, for example, after starting, the range position is set to the P range, which is the initial set family, or from the N range to the D range, which is the travel range, or the R range. In this case, the line pressure P is somewhat reduced, and so-called shift shock is alleviated.
[0038]
The variable related to the oil temperature of the line pressure is not limited to the ATF temperature TATF, and may be, for example, the engine coolant temperature.
[0039]
6 and 7 show a second embodiment of the present invention. In the first embodiment described above, it is determined whether or not the select lever has been switched from the initial set state to the travel range based on the range signal from the inhibitor switch 33. In this embodiment, however, the shift control calculated by the TCU 17 is used. A shift signal for the valve 15 is read to determine whether or not the shift control valve 15 has been switched from the initial state to a different gear position.
[0040]
Therefore, as shown in FIG. 6, as a line pressure control function, a shift operation determination unit 51 is provided instead of the lever operation determination unit 43 shown in FIG. It is determined whether or not the shift valve 7 has shifted from the initial shift state. Then, the determination result is output to the line pressure setting unit 45 and the duration determination unit 44.
[0041]
FIG. 7 shows a line pressure setting routine executed in the present embodiment. First, when the ATF temperature TATF is less than the low temperature determination value TG (TATF <TG) in step S1, a shift signal for controlling the shift control valve 15 is read in step S11 to determine whether or not the gear stage is in an initial state. When it is determined that the initial state is established, the process proceeds to step S3. When the speed change operation is performed from the initial state, the process branches to step S5. The inside line pressure P is controlled.
[0042]
As described above, in this embodiment, when the ATF temperature TATF is a low oil temperature lower than the low temperature determination value TG and the shift stage is in the initial state by the shift signal, the line pressure P in the line pressure passage 1 is controlled to the maximum. Is set to the first control hydraulic pressure PH1, which is a pressure, to quickly start up the line pressure P to prevent delay in response, and when the gear shift operation is performed from the initial state, the line pressure P is set to the intermediate control pressure. By setting the second control hydraulic pressure PH2 as described above, the shift shock can be reduced.
[0043]
The present invention is not limited to the above-described embodiments. For example, when the ATF temperature TATF is a low oil temperature lower than the low temperature determination value TG, both the lever operation by the select lever and the shift operation by the shift valve are performed. The line pressure P is set to the maximum control pressure when both are in the initial state, and the line pressure P is set to the second control hydraulic pressure PH2 when at least one of the select lever and the shift valve is operated. good.
[0044]
【The invention's effect】
According to the first aspect of the present invention, when the variable related to the oil temperature of the line pressure for performing the shifting operation is high viscosity, which is lower than the low temperature judgment value, the line pressure is set in the state where the select lever at the start is in the initial set state. Is set to the first control oil pressure that is higher than the normal control oil pressure, and the line pressure is quickly raised to eliminate response delays during gear shifting operations, and to operate the select lever from the initial set state to the travel range, etc. In this case, the line pressure is set to a second control oil pressure that is higher than the normal control oil pressure and lower than the first control oil pressure, so that a so-called shift shock at the time of a subsequent shift is alleviated.
[0045]
In the invention according to claim 2, even when the variable relating to the oil temperature of the line pressure for performing the speed change operation is lower than the low temperature judgment value and the select lever at the time of starting is in the initial set state, the initial set state is longer than the set time. When the operation continues, by setting the line pressure to the second control oil pressure, in addition to the effect of the first aspect of the invention, the line pressure is prevented from rising more than necessary, and at the time of shifting operation. This so-called shift shock can be further alleviated.
[0046]
According to a third aspect of the present invention, when the variable related to the oil temperature of the line pressure for performing the shifting operation is highly viscous and lower than the low temperature judgment value, and when the shift stage of the automatic transmission is in the initial state, the line pressure is set to the normal control hydraulic pressure. By setting the first control oil pressure to a higher value, the line pressure is quickly raised, the response delay at the time of the subsequent shift is eliminated, and at the time of the shift, the line pressure is higher than the normal control oil pressure and the above-mentioned Since the second control oil pressure is set lower than the first control oil pressure, the so-called shift shock during the subsequent shift, that is, the second and subsequent shift operations is alleviated.
[0047]
In the invention according to claim 4, even if the variable relating to the oil temperature of the line pressure for performing the shift operation is lower than the low temperature judgment value and the shift stage of the automatic transmission remains in the initial state, the initial state is longer than the set time. When the operation is continued, the line pressure is set to the second control oil pressure to suppress the line pressure from rising more than necessary in addition to the effect of the invention of claim 3, and at the time of shifting The so-called shift shock can be further alleviated.
[Brief description of the drawings]
FIG. 1 is a functional block diagram of a line pressure control apparatus according to a first embodiment of the present invention.
FIG. 2 is a flowchart showing the line pressure setting routine.
FIG. 3 is a chart showing the relationship between the duty ratio and the line pressure for the line pressure control valve.
FIG. 4 is a circuit configuration diagram of the transmission control device.
FIG. 5 is a hydraulic circuit diagram of the line pressure control device.
FIG. 6 is a functional block diagram of a line pressure control device according to a second embodiment of the present invention.
FIG. 7 is a flowchart showing the same line pressure setting routine.
[Explanation of symbols]
41. Oil temperature judging means
43 ... Lever judging means
44 ... Duration determining means
45. Line pressure setting means
51. Shifting operation determining means
P ... Line pressure
PH1 ... First control hydraulic pressure
PH2 ... Second control hydraulic pressure
P0: Normal control pressure
TATF ... variable
TG: Low temperature judgment value
time ... duration
tO ... set time

Claims (4)

An oil temperature determining means for detecting a variable related to the oil temperature of the automatic transmission line pressure and comparing the variable with a low temperature determination value;
Lever operation determining means for determining whether the select lever is in the initial set state;
When the variable is not more than the low temperature judgment value and the select lever is in the initial set state, the line pressure is set to a first control oil pressure that is higher than the normal control oil pressure, and the variable is not more than the low temperature judgment value and the select pressure is set. When the lever is set to the travel range, the line pressure is set to a second control oil pressure that is higher than the normal control oil pressure and lower than the first control oil pressure, and when the variable is higher than the low temperature determination value, A line pressure control device for an automatic transmission, comprising line pressure setting means for setting the line pressure to a normal control oil pressure. An oil temperature determining means for detecting a variable related to the oil temperature of the automatic transmission line pressure and comparing the variable with a low temperature determination value;
Lever operation determining means for determining whether the select lever is in the initial set state;
A time determination means for measuring a time duration of the initial setting state of the select lever and comparing the time duration with a set time;
When the variable is not more than the low temperature judgment value and the duration is within the set time, the line pressure is set to a first control oil pressure higher than the normal control oil pressure, the variable is not more than the low temperature judgment value and the select When the lever is set to the traveling range, or when the variable is not more than the low temperature determination value and the duration has reached the set time, the line pressure is higher than the normal control oil pressure and lower than the first control oil pressure. Line pressure control for an automatic transmission comprising: a second control oil pressure; and line pressure setting means for setting the line pressure to a normal control oil pressure when the variable is higher than the low temperature determination value. apparatus. An oil temperature determining means for detecting a variable related to the oil temperature of the automatic transmission line pressure and comparing the variable with a low temperature determination value;
Shift operation determining means for determining whether the shift stage of the automatic transmission is in an initial state;
When the variable is equal to or lower than the low temperature determination value and the gear position is in an initial state, the line pressure is set to a first control hydraulic pressure that is higher than the normal control hydraulic pressure, and the variable is equal to or lower than the low temperature determination value and the automatic shift is performed. When the gear stage of the machine shifts from the initial state, the line pressure is set to a second control oil pressure that is higher than the normal control oil pressure and lower than the first control oil pressure, and the variable is higher than the low temperature determination value. And a line pressure setting means for setting the line pressure to a normal control oil pressure. An oil temperature determining means for detecting a variable related to the oil temperature of the automatic transmission line pressure and comparing the variable with a low temperature determination value;
Shift operation determining means for determining whether the shift stage of the automatic transmission is in an initial state;
A duration determination means for measuring the duration of the initial state of the gear and comparing the duration with a set time;
When the variable is not more than the low temperature determination value and the duration is within the set time, the line pressure is set to a first control oil pressure that is higher than the normal control oil pressure, and the variable is not more than the low temperature determination value and the automatic When the transmission shifts from an initial state, or when the variable is equal to or lower than the low temperature determination value and the duration has reached the set time, the line pressure is higher than the normal control hydraulic pressure and higher than the first control hydraulic pressure. Line pressure setting means for setting a low second control hydraulic pressure and setting the line pressure to a normal control hydraulic pressure when the variable is higher than the low temperature judgment value. Control device.

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