JP3227660B2 - Hydraulic control device for hydraulically operated transmission for vehicle - Google Patents

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 a hydraulically operated transmission for a vehicle.

[0002]

2. Description of the Related Art When various functions such as a shift shock prevention function, a creep prevention function, and a torque converter slip control function are added to improve the performance of a hydraulically operated transmission for a vehicle, the hydraulic pressure can be controlled by electronic control. It will be advantageous. In electronic control, a hydraulic control circuit is provided with an electromagnetic valve that adjusts and outputs a hydraulic pressure supplied from a hydraulic source to a hydraulic pressure according to an electric signal, and a required adjusted hydraulic pressure according to an operation state is obtained. As described above, it is general to control an electric signal to an electromagnetic valve by an electronic control circuit. by the way,
If the oil temperature of the transmission changes and the viscosity of the oil changes, it is no longer possible to obtain the required adjusted oil pressure even if a conventional electric signal is given to the solenoid valve. Therefore, conventionally, Japanese Patent Application Laid-Open No. 63-62964 is disclosed.
No. As seen in Japanese and Sho 62-63248 discloses, an oil temperature sensor for detecting the oil temperature of the transmission is provided, so as to modify in accordance with the electrical signal to the electromagnetic valve on the detection result of the oil temperature sensor I have to.

[0003]

The provision of the oil temperature sensor as described above increases the cost, and it is desired that the required adjusted hydraulic pressure can be obtained without using a special sensor. Accordingly, an object of the present invention is to provide a control device for a hydraulically operated transmission for a vehicle that meets such a demand.

[0004]

In order to achieve the above object,
The present invention relates to a hydraulic control device for a hydraulically operated transmission for a vehicle, comprising a solenoid valve that adjusts a hydraulic pressure supplied from a hydraulic source to a hydraulic pressure according to an electric signal and outputs the adjusted hydraulic pressure.
Oil pressure determining means for determining the control oil pressure to be output from the magnetic valve
Current value to the solenoid valve and output hydraulic pressure of the solenoid valve
From predetermined data representing the relationship with the control hydraulic pressure.
Current value calculating means for obtaining a command current value corresponding to
Application corresponding to the command current value based on the characteristics of the solenoid valve
Voltage calculating means for obtaining a voltage; and
After applying the current to the valve, the actual current flowing through the solenoid valve is detected.
So that the actual current value matches the command current value.
Feedback control means for pressure feedback control
When the resistance change detecting means for detecting a change in the energization resistance value of the solenoid valve from the actual current value and the applied voltage, oil temperature estimating the oil temperature of the transmission based on the detection result of the resistance change detecting means
Estimating means, an energizing current value to the solenoid valve,
The data representing the relationship with the output oil pressure is used as the oil temperature estimating means.
And changing means for changing according to the estimation result .

[0005]

The temperature of the solenoid valve substantially coincides with the oil temperature of the transmission, and when the oil temperature changes, the energization resistance of the solenoid valve also changes. Soshi
Therefore, according to the present invention, the command current value corresponding to the control oil pressure is
Varying to compensate for oil temperature changes on the basis of the data representing the relationship between hydraulic and electric current to be used for change of <br/> energization resistance value when obtaining
The required adjusted hydraulic pressure can be obtained even if the oil temperature changes.
By the way, since the energization resistance of the solenoid valve also changes due to heat generated by energization, an error may occur in estimating the oil temperature using only the energization resistance. In this case, if the temperature of the cooling water of the engine placed in the same environment as the transmission is detected and the oil temperature is estimated in consideration of the cooling water temperature, the oil temperature can be known more accurately, and the control accuracy of the hydraulic pressure is improved. I do.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 1, reference numeral 1 denotes a hydraulically operated transmission for a vehicle. The transmission 1 is a torque converter 3 having a lock-up clutch 3a provided on the output side of an engine 2.
And an auxiliary transmission 4 provided on the output side of the torque converter 3.

The auxiliary transmission 4 is provided between an input shaft 4a connected to the torque converter 3 and an output shaft 4b connected to driving wheels 5, 5 of the vehicle via a differential gear 6 for forward movement. To fourth speed shift stages G1, G2, G3, G4 and reverse gear GR
The first to fourth speed hydraulic clutches C1, C2, C3, and C4 are provided at each forward speed, and each forward speed is engaged by engagement of each hydraulic clutch. The shift speed is selectively established. The reverse gear GR shares the fourth gear G4 and the fourth hydraulic clutch C4. A selector gear 7 for selecting the fourth gear G4 and the reverse gear GR is provided on the output shaft 4b. In the drawing, the fourth speed G4 and the reverse speed GR are selectively established by the switching operation between the left forward position and the right reverse position. In the drawing, reference numeral 8 denotes a one-way clutch provided at the first speed stage G1, which functions so as to allow overspeed on the output side.

The hydraulic clutches C1 to C4, the lock-up clutch 3a and the selector gear 7 are controlled by an electronic control circuit 9 comprising a microcomputer via a hydraulic control circuit 10.
And a throttle sensor 11 ₁ which detects a throttle opening of the engine 2, the rotational speed and the rotation sensor 11 ₂ which detects the engine 2, and a water temperature sensor 11 ₃ which detects the coolant temperature of the engine 2, the rotational speed of the differential gear 6 a vehicle speed sensor 11 for detecting the vehicle speed from ₄ and an input shaft 4a of the auxiliary transmission 4 output shaft 4
When signals from rotation sensors 11 ₅ and 11 ₆ for detecting the number of rotations of b are input and a shift lever (not shown) is switched to an automatic shift range, a shift characteristic preset with the throttle opening and the vehicle speed as parameters. Output a shift command according to
Oil is supplied to a required hydraulic clutch via a shift valve unit (not shown) provided in the hydraulic control circuit 10 so as to perform first- to fourth-speed automatic shifting.

As shown in FIG. 2, the hydraulic control circuit 10
A pressure regulating valve 12 for regulating a line pressure PL from a hydraulic pressure source and supplying the same to a shift valve unit is provided. Further, an electromagnetic valve 14 for reducing and inputting the line pressure PL by a constant value by a modulator valve 13 is provided. The control oil pressure Pc output from the solenoid valve 14 is applied in the pressure increasing direction of the pressure regulating valve 12, and the supply hydraulic pressure to the hydraulic clutch is controlled by the solenoid valve 14 via the pressure regulating valve 12 during a shift transition period.

The solenoid valve 14 is composed of a linear solenoid valve that outputs a control oil pressure Pc that is inversely proportional to the value of the current supplied to the solenoid 14a, and the electronic control circuit 9 controls the power supply to the solenoid 14a. More specifically, the electronic control circuit 9 determines the control oil pressure Pc to be output from the solenoid valve 14 according to the parameter such as the throttle opening and the type of shift, and then determines the control oil pressure Pc of the solenoid valve 14.
A hydraulic pressure-current map as shown in FIG. 4 showing the relationship between the value of the current supplied to a and the hydraulic pressure output from the solenoid valve 14 is searched to calculate a command current value Ic corresponding to the control hydraulic pressure Pc. The voltage corresponding to Ic is calculated in accordance with the current-voltage characteristics as shown in (1), and this voltage is applied to the solenoid 14a. Then, at this time, the actual current value Ia flowing through the solenoid 14a is detected, the deviation between Ic and Ia is proportionally integrated, and the applied voltage Va of the solenoid 14a is feedback-controlled to make Ia equal to Ic.

When the viscosity of the oil changes due to a change in the oil temperature of the transmission 1, it is necessary to change the hydraulic-current map accordingly. For example, when the viscosity of the oil increases at a low temperature, in order to compensate for the response delay of the oil pressure change, a in FIG.
It is necessary to correct in the high voltage direction (direction for decreasing the current) as shown by the line b in the same figure from the map at normal temperature indicated by the line,
Further, even when the viscosity of the oil decreases at a high temperature, the amount of oil leaking from the sliding clearance of the valve spool increases, so that it is necessary to correct the oil pressure from the map at normal temperature to the high pressure direction as shown by the line c in FIG. is there.

Here, when the oil temperature changes, the temperature of the solenoid valve 14 also changes, the energization resistance value R of the solenoid 14a changes, and the slope of the current-voltage characteristic of the solenoid 14a changes to the slope at normal temperature indicated by a solid line. On the other hand, it becomes larger at high temperature and smaller at low temperature. Therefore, if the actual resistance value Ra is calculated from the applied voltage Va of the solenoid 14a and the actual current value Ia,
The oil temperature can be estimated from Ra, and a change in the oil temperature can be compensated by selecting a hydraulic-current map according to the oil temperature. However, the actual resistance value Ra also changes due to the self-heating of the solenoid 14a, and an error may occur if the oil temperature is estimated using only Ra. for that reason,
The oil temperature is estimated according to the map shown in FIG. 6 in consideration of the cooling water temperature TW of the engine 2. That is, a low-temperature discrimination value RL and a high-temperature discrimination value RH for the resistance value are set, and a low-temperature discrimination value TWL and a high-temperature discrimination value TWH for the water temperature are set. When Ra ≦ RL, the oil temperature is low.
When a ≧ RH, the oil temperature is determined to be high, and RL <Ra <R
When H, the oil temperature is low when TW ≦ TWL, taking into account the resistance change due to self-heating of the solenoid 14a, and TWL
When <TW <TWH, it is determined that the oil temperature is normal temperature, and when TW ≧ TWH, it is determined that the oil temperature is high.

The above-mentioned solenoid valve 14 by the electronic control circuit 9
3 is summarized as shown in FIG. 3. First, in step S1, various parameters such as the throttle opening and the coolant temperature TW are read, and in step S2, the type of shift is determined. Then, the optimum control oil pressure Pc for preventing the shift shock is determined from the type of shift and parameters such as the throttle opening. Next, after the command current value Ic corresponding to Pc is calculated in step S4, the applied voltage corresponding to Ic is calculated and output in step S5.
Then, in step S6, the actual current value Ia is detected to perform feedback control, and in step S7, the actual resistance value Ra is calculated from the applied voltages Va and Ia, and then, in step S8, the actual resistance value Ra is calculated from Ra and TW. The oil temperature is estimated, and a hydraulic pressure-current map corresponding to the oil temperature is selected in step S9. Then, at the time of the next shift, the calculation of Ic in the step S4 is performed based on the hydraulic pressure-current map selected in the previous step S9.

Although the embodiment in which the hydraulic pressure is controlled by the proportional solenoid valve 14 has been described above, the present invention can also be applied to a system in which the hydraulic pressure is controlled by a duty control solenoid valve.
In this case, the oil temperature is estimated by calculating the resistance value from the drive duty ratio and the effective current value of the solenoid valve, and the data map representing the relationship between the oil pressure and the drive duty ratio is changed according to the oil temperature.

[0015]

As is clear from the above description, according to the present invention, even if the oil temperature changes, the hydraulic pressure can be accurately controlled by the solenoid valve, and a special sensor such as an oil temperature sensor is not required. In addition, costs can be reduced.

[Brief description of the drawings]

FIG. 1 is a system diagram showing a transmission to which the present invention is applied and a control system thereof.

FIG. 2 is a diagram showing an electromagnetic valve provided in the hydraulic control circuit.

FIG. 3 is a flowchart showing a control program for a solenoid valve.

FIG. 4 is a diagram showing hydraulic-current characteristics of a solenoid valve.

FIG. 5 is a diagram showing current-voltage characteristics of a solenoid valve.

FIG. 6 is a diagram showing an oil temperature discrimination map based on a resistance value and a cooling water temperature.

[Explanation of symbols]

1 transmission 2 engine 9
Electronic control circuit 10 Hydraulic control circuit 14 Solenoid valve

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int. Cl. ⁷ , DB name) F16H 61/00-61/24

Claims (2)

(57) [Claims] 1. A hydraulic control apparatus for a hydraulically operated vehicular transmission, in which comprises a solenoid valve for hydraulic pressure supplied to adjust the hydraulic pressure corresponding to the electric signal output from the hydraulic source, before
Hydraulic pressure determining means for determining the control hydraulic pressure to be output from the solenoid valve
Stage, the current flowing through the solenoid valve and the output oil of the solenoid valve
The control oil is obtained from predetermined data representing a relationship with pressure.
Current value calculating means for obtaining a command current value corresponding to the pressure;
A mark corresponding to the command current value based on the characteristics of the solenoid valve.
Voltage calculation means for obtaining an applied voltage;
After applying the voltage to the magnetic valve, the actual current value flowing through the electromagnetic valve is detected.
So that the actual current value matches the command current value.
Feedback control means for pressure feedback control
Resistance change detection means for detecting a change in the energization resistance value of the solenoid valve from an actual current value and an applied voltage; and an oil temperature for estimating an oil temperature of the transmission based on a detection result of the resistance change detection means.
Estimating means, an energizing current value to the solenoid valve,
The data representing the relationship with the output oil pressure is used as the oil temperature estimating means.
And a changing means for changing according to a result of the estimation of the hydraulic control apparatus for a vehicle hydraulically operated transmission. 2. An oil temperature estimating means for detecting a cooling water temperature of an engine, wherein the oil temperature estimating means estimates an oil temperature in consideration of a detection result of the water temperature detecting means.
2. The hydraulic control device for a hydraulically operated transmission for a vehicle according to claim 1 .