KR100203873B1 - Shift control method of auto transmission in low temperature - Google Patents

Abstract

Solenoid valve by transmission control unit that receives signals such as throttle opening degree, oil temperature, engine speed, inhibitor switch, etc. In a shift control method of an automatic transmission vehicle that is turned on / off to control friction elements of a hydraulic control device, when the throttle opening degree and the engine speed are lower than the set value at low temperature when the oil temperature is lower than the set value, the shift is made only by the vehicle speed below the set value. A shift control method at low temperature of the automatic transmission vehicle, characterized in that made.

Description

Shift control method at low temperature of automatic shift vehicle

1 is a block diagram showing a configuration for realizing a shift control method according to the present invention.

2 is an operation flowchart of a shift control method according to the present invention.

3 is a shift diagram illustrating a shift pattern according to the shift control method according to the present invention and a conventional shift pattern.

The present invention relates to a shift control method at low temperature of an automatic shift vehicle, and more particularly, a shift control method for improving the performance of the catalytic converter by increasing the number of revolutions of the engine at low temperatures and reducing the shift frequency to improve the shifting feeling. It is about.

In general, an automatic shift vehicle sets a shift pattern that can be appropriately shifted according to engine performance and driving conditions.

The electronically controlled four-speed vehicle has sufficient reliability and durability in response to the power performance of high-powered engines, and has two driving modes: the economy range for low fuel consumption and low noise, and the power range for sportier driving. Have

This automatic transmission vehicle has a longer speed gear area when the valve is opened more than when the throttle valve is opened, which requires a long driving state of a low gear with a high driving force when the throttle valve is opened at the same vehicle speed. Because.

In addition, if the throttle opening is suddenly increased while driving at a constant vehicle speed, the driving speed can be lowered to a lower gear than the current gear, and a large driving force can be obtained. Has a pattern.

In such automatic transmission vehicles, friction elements selected by shift valves in which port conversion is made by the transmission control unit are actuated, and it is fluid that actually operates the friction elements.

The fluid is discharged from the oil pump which is driven together when the engine is driven, and is supplied to each shift valve. The fluid has a great influence on the operation of the shift valve as the viscosity changes with temperature.

However, when the automatic transmission vehicle runs at low temperature, the emission amount increases due to incomplete combustion in the continuous room, and a catalytic converter is installed in the exhaust system to reduce harmful substances in the exhaust gas.

Such a catalytic converter can be improved to function only when it is heated to a constant temperature necessary for chemical reaction, but the function of the catalytic converter does not rise to the temperature required for catalytic activity during low temperature driving, and thus the function is deteriorated. .

And the automatic shifting vehicle is shifted by a constant shift pattern. At low temperatures, frequent shifting at low temperatures becomes a deteriorating factor because the fluid does not operate smoothly when the fluid operates the friction elements.

The present invention has been invented to solve the problems of the prior art as described above, the object of the present invention is to improve the speed of the shift and at the same time to increase the number of revolutions of the engine at low temperatures to improve the function of the catalytic converter in a short time A low speed shift control method of an automatic shift vehicle is provided.

In order to realize the object of the present invention as described above, the solenoid valve is turned on / off by a transmission control unit that receives signals such as throttle opening degree, oil temperature, engine speed, inhibitor switch, and the like. In a shift control method of an automatic transmission vehicle that controls the engine speed change, when the throttle opening degree and the engine rotation speed are lower than the set value when the oil temperature is lower than the set value, the shift is performed only by the vehicle speed below the set value. Provides a shift control method.

Hereinafter, preferred embodiments of the present invention will be described in more detail with reference to the accompanying drawings.

FIG. 1 is a block diagram showing a configuration for realizing a shift control method according to the present invention, and an oil temperature sensor 2 for detecting a temperature of an automatic transmission fluid at an input of a transmission control unit TCU. Is connected, and a pulse generator 4 for measuring the rotational speed of the transfer drive gear and a throttle opening sensor 6 for measuring the throttle opening rate are respectively connected to measure the rotational speed of the engine.

The output end of the transmission control unit (TCU) is connected to a hydraulic control unit 8 for controlling a plurality of solenoid valves for controlling each shift valve, and the output end of the hydraulic control unit with respect to the valve spool of the shift control valve. Solenoid valves A and B, which can generate displacement, are electrically connected.

2 is a shift control routine of a transmission control unit according to the present invention, in which a signal input from the oil temperature sensor 2 is judged to determine whether the oil temperature is higher than the memory value (10), and the throttle opening degree is set. A step 20 for determining whether it is larger, a step 30 for determining whether the engine speed is higher than a set value, and a target shift stage setting step 40 at low temperature are included.

And a mode selection switch selection step 50 for selecting a mode when the oil temperature is higher than the set value in step 10, and a target shift stage setting step 60 at room temperature.

In the control method of the present invention having such an algorithm, the signal input from the oil temperature sensor 2 is determined in step 10 to determine whether the temperature is higher than the set value.

At this time, if the oil temperature is higher than the set value, the target shift stage is set at room temperature in step 60 depending on the mode selected in step 50, for example, the economic range or the power range.

If the determination in step 10 is a low oil temperature, in step 20, the opening degree of the throttle valve is compared with the set value, and if the throttle opening degree is large, step 50 is controlled, and if the throttle opening degree is small, the step ( In 30) it is determined whether the engine speed is higher than the set value.

At this time, if the determination value indicates that the engine speed is high, the process is controlled by step 50, and when the engine speed is low, the target speed change stage at low temperature is set.

3 is a comparison of the shift pattern and the general shift pattern of the present invention represented by the above-described control method. In the control step 20 of the present invention, the throttle opening rate is set to about 50%, and the control step ( In Fig. 30, the engine speed is set to 1-2 speeds of 700 rpm, 2-3 speeds of 1000 rpm, and 3-4 speeds of 1300 rpm.

According to this shift pattern, the 1-2 shift at low temperature is maintained at 1 speed until the throttle opening becomes 50% and the engine speed reaches 700 rpm, and then shifts to 2 speed when the speed becomes larger than the condition.

This shows that the speed of the shift is low when the conventional shift pattern (shown by dashed line) is shifted at a throttle opening rate of 50% or less and at an engine speed of 700 rpm or less.

The shift is the same in the 2-3 and 3-4 shifts, and the shift is only performed by the vehicle speed, so that the shift is not made before the throttle opening degree exceeds a certain rate, thereby improving the shifting feeling.

In addition, since the shift control is performed in a state in which the engine speed is increased, the temperature of the exhaust system through which the exhaust gas of the engine is discharged can be increased, so that the temperature of the catalytic converter of the exhaust system can be increased faster than before.

Therefore, it is possible to reduce the amount of harmful substances emitted by activating the harmful substances in the exhaust gas at low temperatures.

Claims (1)

The transmission control unit receives signals such as throttle opening, oil temperature, engine speed, and inhibitor switch, so that the solenoid valve is turned on and off to control each friction element of the hydraulic control device so that the shift is made. A shift control method comprising: a first step of determining whether an oil temperature is equal to or greater than a set value; A second step of determining whether the throttle opening degree is greater than or equal to the preset value when the oil temperature is less than or equal to the preset value in the step; A third step of determining whether the engine speed is greater than or equal to the set value when the throttle opening degree is smaller than or equal to the set value in the step; A fourth step of setting the low temperature target speed change stage only by the vehicle speed when the engine speed is less than the set value in the above step; If any of the first, second, and third steps is determined to be greater than or equal to the set value, the fifth step of setting the room temperature target shift stage by determining the mode selected by the shift mode switch is performed at low temperature. Control method.