KR100279420B1 - Shift control method of automatic transmission - Google Patents

Abstract

The present invention relates to a shift control method of an automatic transmission. When the shift stage is shifting synchronous, the initial duty and duty stored in the memory power-up shift map of the shift control means are determined by determining whether the shift stage is a power-off up shift shift state. Setting a slope and a duty output time to output a corresponding duty control signal; Comparing the turbine speed with the engine speed from the time when the turbine speed becomes greater than the engine speed; Determining whether the difference between the turbine speed and the engine speed reaches a set RPM and performing a certain amount of duty correction based on the time point; It is composed of the step of stopping the output of all duty control signals when a predetermined time elapses after determining the completion of the shift synchronization. When the accelerator pedal is released in a driving vehicle, if the shift is made due to the shift synchronization, the hydraulic response In consideration of the characteristics, the turbine speed and the engine speed are compared when the turbine speed is greater than the engine speed, and the turbine speed minus the engine speed is smaller than the set reference speed (αRPM). Precise duty control can be performed by compensating a certain amount of duty to the duty currently in progress, so that a constant shift feeling can be secured against hydraulic deviation at all times, and shifting to stop of all duty control after a certain time has elapsed after the shift synchronization completion point is detected. This can shorten the time.

Description

Shift control method of automatic transmission

1 is an automatic transmission shift control pattern of the prior art,

2 is a shift control pattern of an automatic transmission according to an embodiment of the present invention,

3 is a block diagram of a shift control apparatus of an automatic transmission according to an embodiment of the present invention,

4 is a flowchart of a shift control operation of an automatic transmission according to an embodiment of the present invention.

The present invention relates to a shift control method of an automatic transmission. More specifically, the speed of a turbine is increased in a state in which a reverse driving force is generated in the engine by shifting the shift stage from 2 to 5 speeds by turning off the accelerator pedal while driving the vehicle. The present invention relates to a shift control method of an automatic transmission for compensating for a duty before a point in time lower than an RPM of an engine to prevent a shift shock caused by a hydraulic deviation and a forced shift, thereby achieving a constant and smooth shift.

In general, a vehicle equipped with an automatic transmission controls the hydraulic pressure within a shift range set according to the driving speed of the vehicle so that the shift gear of the target shift stage may be automatically operated.

Therefore, the torque converter is operated according to the output power of the engine to control the rotational force of the fluid, and according to the control signal applied from the shift control device so that the shift gear according to the operating state of the vehicle can be operated. The hydraulic pressure acts on the valve so that the shifting operation can be performed.

Therefore, a vehicle equipped with an automatic transmission in which the operating state is controlled according to the hydraulic pressure does not require the operation of a clutch pedal to cut off power from the engine in order to change the operating state of the corresponding shift gear. Fatigue can be reduced, and an engine stall is not generated due to a malfunction of the driver or an immature driving during driving, so that even a beginner can easily operate a driving operation.

Therefore, the automatic transmission receives a fluid pressure from the oil pump by changing the port according to the selected position of the driver's shift lever, and the operating state of the hydraulic valve is changed by the fluid pressure so that any one of the gear stages of the transmission gear mechanism is shifted. Controls the operating state of the hydraulically actuated friction element for selecting stages.

The action of the planetary gear arrangement is switched in accordance with the selective operation of the friction element consisting of a clutch or brake, which is then transmitted to the drive gear after an appropriate transmission ratio is made.

When the shifted power is transmitted to the drive gear, the shifted power is transmitted to the driven gear geared to the longitudinal reduction gear by the driven gear geared to the drive gear, thereby controlling the rotational movement of the wheel.

As described above, the target shift stage is determined according to the driving state of the vehicle, and when the control operation to the determined target shift stage is executed, the corresponding friction element is operated for each target shift stage among friction elements consisting of a clutch or a brake. Let's do it.

Hereinafter, a conventional technology will be described with reference to the accompanying drawings.

As shown in FIG. 1, when the accelerator pedal is released in a vehicle traveling in the second speed in the automatic transmission, the shift stage is shifted to five speeds to maintain the current vehicle speed, and the duty control generates a shift command accordingly. The hydraulic pressure was controlled by outputting a duty control signal with a slope of two stages with a certain duty control time from the time point.

However, the conventional technique described above, when the shift pedal is shifted up to 5 speeds by turning off the accelerator pedal at 2 speeds, the throttle opening degree drops from 100% to 0%.

Therefore, if the output torque is reversed to the engine and the engine brake occurs, when the 5-speed synchronization is completed due to the deviation of the hydraulic pressure or temperature that engages the clutch and brake for shifting the target gear, There is a problem that a shock occurs because the duty of maintaining the control pressure is not accurately controlled.

In addition, since the duty control for synchronizing the target shift stage is controlled with two inclinations, accurate duty control is difficult and there is a problem that a change in the shifting feeling occurs due to the hydraulic deviation.

Accordingly, an object of the present invention is to solve the above-described problems, and when the accelerator pedal is released in a running vehicle, if the shift is made due to shift synchronism, the turbine speed is higher than the engine speed in consideration of the hydraulic response characteristics. When the rotation speed becomes large, the turbine speed and the engine speed are compared, and a certain amount of duty is compensated for the ongoing duty from the time when the turbine speed minus the engine speed is smaller than the set reference speed (αRPM). It can carry out precise duty control, so it can always secure a constant shift feeling against hydraulic deviation and shorten the shift time by stopping all duty control after a certain time has elapsed after detecting the shift synchronization completion time. It is to provide a shift control method of an automatic transmission.

The present invention for achieving the above object is, if the shift stage is in shift synchronism, it is determined whether the shift stage is the power-off up shift shift state, and the initial duty and duty gradient stored in the memory power-up shift map of the shift control means; Setting a duty output time to output a corresponding duty control signal; Comparing the turbine speed with the engine speed from the time when the turbine speed becomes greater than the engine speed; Determining a set RPM before the time when the turbine speed and the engine speed are the same, and performing a certain amount of duty correction based on the time; It is characterized in that it comprises the step of stopping the output of all the duty control signal after a predetermined time elapsed by determining the shift synchronization completion time.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention that can specifically realize the above objects will be described in detail with reference to the accompanying drawings.

A shift control apparatus for an automatic transmission according to an exemplary embodiment of the present invention will be described with reference to FIG. 3.

A vehicle driving state detection unit 10 which outputs a signal that varies according to the driving state of the vehicle; When the shift synchronization is started by receiving the signal output from the vehicle driving state detecting unit 10, the turbine rotation speed and the engine rotation speed are compared, and when the turbine rotational speed is lower than the engine rotation speed, the shifted speed is corrected by a certain amount. A shift control unit 20 for preventing shock and ending the output of all duty signals after a predetermined time has been found after the shift synchronizing time has been found; It consists of a drive unit 30 made of a solenoid valve for adjusting the hydraulic pressure in accordance with the duty control signal output from the shift control unit 20.

In the above, the vehicle driving state detection unit 10, the throttle opening degree detection means for detecting the opening degree of the throttle valve whose opening and closing state is variable according to the operation of the accelerator pedal and outputs a corresponding electrical signal; Vehicle speed detecting means (12) for detecting a speed of a vehicle being driven and outputting a corresponding signal; Engine rotation speed detection means (13) for detecting the rotational speed of the crankshaft which is varied according to the operating state of the engine and outputting a corresponding signal; Turbine shaft rotational speed detection means 14 for detecting the rotational speed of the turbine side of the torque converter connected to the input side of the transmission and outputs a corresponding signal.

By the above configuration, the operation of the shift control method in the automatic transmission according to the embodiment of the present invention is as follows.

For example, referring to the accompanying FIG. 4, when the driver releases the foot from the accelerator pedal in a vehicle traveling at two speeds, the shift stage starts shifting the power-up up (S100). 20 determines whether the state of the current shift stage is a power-off up-shift state that is a reverse driving force state (S110).

If the shift stage is not in the power-off up shift state, all the procedures are terminated and the process returns to the initial stage.

When the shift stage is in the power-off upshift state, the initial duty is set by the power-up shift map stored in the memory of the shift control unit 20, the duty gradient is calculated, and the duty output time is set. The duty control signal is output (S120).

In the process of outputting the duty control signal, the turbine speed and the engine speed are compared based on the point in time when the turbine speed in the torque converter of the automatic transmission is greater than the engine speed, as shown in FIG. Start to (S130).

In outputting the duty control signal while continuously comparing the engine speed and the turbine speed, the shift that occurs when the engine speed becomes larger than the turbine speed in consideration of hydraulic response characteristics as shown in FIG. 1. To prevent shock, a certain amount of duty is compensated at the point where the engine speed and the turbine speed are closest to each other.

The above-mentioned step of determining the duty correction timing at which the duty correction is performed is expressed by the following equation.

N _T ≤ N _E + △ N

(N _T : Current turbine speed, N _E : Current engine speed, ΔN: Turbine speed and engine speed are closest to each other.

That is, ΔN time is determined before the shift synchronization is completed, which is the point at which the engine rotational speed and the turbine rotational speed are the same (S140), and the duty amount by β% is corrected to the output value of the duty control signal currently in progress (S150).

Therefore, in order to prevent the shift shock from occurring because the speed of the turbine is lowered below the engine speed due to the operation of the engine brake during the shifting operation in order to reach the target speed change stage (S110) in order to reach the target speed change stage (S140). ), The control pressure rising to a constant pressure is compensated for the duty β% by the duty correction amount.

Accordingly, as the time for which the clutch is fastened to the disk is relatively delayed, the turbine rotational speed is prevented from falling below the engine rotational speed, and the rotation speed is maintained constant with the engine rotational speed, thereby stably reaching the target shift stage.

The shift control unit 20 determines whether the shift stage reaches the target shift stage according to the above operation sequence (S160).

In the above, a method of confirming the timing at which the shift stage reaches the target shift stage S.F is expressed by the following equation.

N _T 〈N _TO + 50

(N _T : current turbine speed, N _TO : vehicle speed N _O × 5 gear ratio, 50: variable speed turbine speed.)

Therefore, when the shift stage reaches the target shift stage, the output of all the duty control signals is stopped after all the set time δ elapses and all the operations are terminated (S170).

However, if the determination conditions are not satisfied, the process returns to the initial stage and outputs a continuous duty control signal until the determination conditions are satisfied.

The most preferred embodiments have been described in the above-described embodiments, and the present invention is not limited thereto, and the invention can be easily invented from the above embodiments.

As described above, in the embodiment of the present invention, when the accelerator pedal is released in a running vehicle, if the shift is made due to the shift synchronism, the turbine rotation speed becomes larger than the engine speed in consideration of the hydraulic response characteristics. Start comparing the turbine speed and engine speed, and perform precise duty control by compensating a certain amount of duty to the ongoing duty from the time when the turbine speed minus the engine speed is smaller than the set reference speed αRPM. The shift control method in the automatic transmission having the effect of ensuring a constant shift feeling against the hydraulic deviation and reducing the shift time by stopping all duty control after a certain time has elapsed after the shift synchronization completion point is detected. Can be provided.

Claims (3)

In the shift control method of the automatic transmission, if the shift stage is shifting synchronizing, it is determined whether the shift stage is a power-off up shift shift state, and the initial duty, duty gradient, and duty output stored in the memory power-up shift map of the shift control means. Setting a time to output a corresponding duty control signal; Comparing the turbine speed with the engine speed from the time when the turbine speed becomes greater than the engine speed; Determining a set RPM before the time when the turbine speed and the engine speed are the same, and performing a certain amount of duty correction based on the time; The shift control method of the automatic transmission, characterized in that it comprises the step of determining the timing of completion of the shift synchronization and the output of all the duty control signals after a predetermined time elapses. The method of claim 1, wherein the method for determining the duty correction timing includes calculating the current engine speed N _E with a time ΔN at which the turbine speed and the engine speed are closest to each other to perform duty correction. A shift control method of an automatic transmission, comprising comparing whether the current is greater than or equal to the rotation speed N _T. {N _T ≤N _E + ΔN (N _T : Current turbine speed, N _E : Current engine speed △ N: Turbine speed and engine speed are closest to each other and the duty correction time.)} The method of claim 1, wherein the method of checking the timing at which the shift stage reaches the target shift stage SF includes a value calculated by calculating a rotation speed of an arbitrary reference turbine to a value calculated by calculating a current vehicle speed and a gear ratio. If it is greater than the number of revolutions of the turbine, the shift control method of the automatic transmission comprising the determination that the shift stage has reached the target shift stage. (N _T 〈N _TO + 50 (N _T : current turbine speed, N _TO : vehicle speed N _O × 5 gear ratio, 50: variable speed turbine speed.)}