KR20020054172A - Method for reduction controlling a velocity of automatic transmission car before stop - Google Patents

Abstract

PURPOSE: A method for controlling deceleration of an automatic shift car before stop of the car is provided to reduce shock generated when 3→1 or 2→1 down shift deceleration is performed before the automatic shift car is stopped. CONSTITUTION: A method for controlling deceleration of an automatic shift car before stop of the car includes the steps of checking whether or not 3→1 or 2→1 down shift control signal is output before stop of the car when a driver separates foot from an acceleration pedal, maintaining a difference between an engine RPM and a turbine RPM less than a predetermined level at 1 speed synchronization time if the 3→1 down shift control signal is output, and maintaining a difference between an engine RPM and a turbine RPM less than a predetermined level at 1 speed synchronization time if the 2→1 down shift control signal is output.

Description

TECHNICAL FOR REDUCTION CONTROLLING A VELOCITY OF AUTOMATIC TRANSMISSION CAR BEFORE STOP}

The present invention relates to a deceleration control method for an automatic transmission vehicle, and more particularly, a shift shock generated at the end of a shift when a shift stage is controlled at three or one speed by the driver's accelerator pedal during driving. It relates to a deceleration control method before stop of an automatic transmission vehicle for reducing.

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 the valve is controlled 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. Hydraulic pressure is applied to allow shifting operation.

Therefore, a vehicle equipped with an automatic transmission in which the operating state is controlled according to the hydraulic pressure may reduce the driving fatigue of the driver because it does not need the operation of the clutch pedal to cut off power from the engine in order to change the operating state of the corresponding shift gear. In addition, since the engine stall does not occur due to a malfunction of the driver or an immature driving during driving, the driving operation can be facilitated even for a beginner.

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 movement of the friction element, which consists of a clutch or brake, which is then transmitted to the drive gear after an appropriate transmission ratio is made.

The shifted power is transmitted to the drive gear, and the shifted power is transmitted to the driven gear geared to the subordinate gear by the driven gear geared to the drive gear, thereby controlling the rotation of the wheel.

As described above, when controlling the hydraulic state generated by the torque converter to control the shift operation to the target shift stage, the rotation speed between the turbine shaft rotation speed of the torque converter which is the input shaft of the automatic transmission and the output shaft of the automatic transmission is accurately set. Does not coincide with gearshift

Therefore, when the corresponding friction element is released or fastened for the shift operation to the target shift stage, the shift shock occurs because the operating states of the input shaft and the output shaft do not coincide with each other.

FIG. 1 is a diagram for describing a case where a vehicle speed deceleration is small, and FIG. 2 is a diagram for describing a case where a vehicle speed deceleration is large.

Referring to FIG. 1, since the turbine starts to be released in a state in which the slip between the idle turbine RPM Ne and the shift turbine RPM Nt is small, the ascending speed of the shift turbine RPM Nt is reduced, and the shift turbine is somewhat to some extent. After the RPM (Nt) reaches the steady state, the first speed is synchronized, so that the shock at the first speed synchronization point can be reduced due to the increase of the speed turbine (Nt).

However, as shown in FIG. 2, when the vehicle speed deceleration is large, that is, the turbine starts to unwind in a state where the slip between the idle turbine RPM Ne and the transmission turbine RPM Nt is large, the speed of the turbine turbine Nt is changed. As the ascension rate increases, the first speed synchronization is performed while the speed change turbine RPM Nt increases, and there is a problem in that a shock occurs at the speed change point 1 due to the increase in the speed change turbine RPM Nt.

In particular, when the downshift operation is executed to stop the driving operation of the vehicle, there is a problem that the riding comfort of the vehicle is significantly reduced even by a small shock.

Therefore, the technical and problem of the present invention is to solve such a conventional problem, an object of the present invention is the shock generated when the downshift deceleration from 3 speed to 1 speed or from 2 speed to 1 speed before stopping of the automatic transmission vehicle. It is to provide a variable control before deceleration deceleration control method of the automatic transmission vehicle to reduce the.

1 is a view for explaining a case where the vehicle speed deceleration is small.

2 is a view for explaining the case where the vehicle speed deceleration is large.

3 is a view for explaining a variable stop before deceleration control apparatus for an automatic transmission vehicle according to an embodiment of the present invention.

4 is a view for explaining a variable stop deceleration control method of an automatic transmission vehicle according to the present invention.

<Description of the symbols for the main parts of the drawings>

100: vehicle driving state detection unit 200: shift control unit

300: drive unit 110: engine speed detection unit

120: turbine rotation speed detection unit 130: output shaft rotation speed detection unit

140, 150: shift control solenoid valve

According to one aspect for realizing the above object of the present invention, the variable stop deceleration control method of the automatic transmission vehicle,

(a) checking whether the first speed downshift shift control signal is output at the third or second speed before stopping when the driver releases the foot from the accelerator pedal while driving;

(b) maintaining a difference between the engine RPM and the turbine RPM at a predetermined level or less at the first speed synchronizing time as the first speed downshift shift control signal is output at the third speed before stopping in the step (a); And

(c) maintaining the difference between the engine RPM and the turbine RPM at a predetermined level or less at the first speed synchronizing time as the first speed downshift shift control signal is output at the second speed before stopping in the step (a). At this time, in order to keep below a predetermined level in step (b), the three-speed turbine RPM at the shift command start point,

Where Ne is the idle turbine RPM, dNo / dt is the rate of change of the output RPM of the automatic transmission, and t _{3-> 1} is the time from the 3rd to 1st speed signal to the actual 1st speed sync.

In addition, in order to maintain below a certain level in step (c), the 2-speed turbine RPM at the shift control unit shift command start point is

(Where Ne is the idle turbine RPM, dNo / dt is the rate of change of the output RPM of the automatic transmission, and t _{2-> 1} is the time from the second to first speed change signal after the actual first speed synchronization).

According to the variable speed reduction control method of the automatic transmission vehicle, the downshift shift control signal from the 3rd speed or the 2nd speed to the 1st speed before the stop is output from the automatic transmission vehicle. By keeping the difference below a certain level, even if the shift stage is controlled from the 3rd speed to the 1st speed or the 2nd speed to the 1st speed, the shift shock occurring at the end of the shift can be reduced.

Then, embodiments will be described so that those skilled in the art can easily implement the present invention.

3 is a view for explaining a variable stop before deceleration control apparatus for an automatic transmission vehicle according to an embodiment of the present invention.

Referring to FIG. 3, the deceleration control apparatus before stopping of an automatic transmission vehicle according to an exemplary embodiment of the present invention receives a plurality of signals that are output in a state variable according to a driving state of the vehicle and transmits corresponding electric signals to a shift control unit ( When the vehicle driving state detection unit 100 and the vehicle driving state detection unit 100 output the signals output from the vehicle driving state detection unit 100 and are checked as deceleration before stop, the shift shock at the first speed synchronization point is reduced. The driving unit 300 is configured to output a signal for performing a shift synchronizing operation, and to shift the shift stage to the target shift stage by receiving a signal output from the shift control unit 200.

Here, the vehicle driving state detection unit 100 is the engine speed detection unit 110, the turbine speed detection unit 120, the output shaft speed detection unit 130, the first shift control solenoid valve 140 and the second A shift control solenoid valve 150.

More specifically, the engine speed detection unit 110 detects the rotational speed of the crankshaft variable according to the operating state of the engine and outputs a corresponding signal to the transmission control unit 200, the turbine speed detection unit 120 is a transmission It detects the rotational speed of the turbine shaft of the torque converter connected to the input shaft of and outputs the corresponding signal to the shift control unit 200.

In addition, the output shaft rotation speed detection unit 130 detects the output shaft rotation speed for outputting different values according to the fastening state of the vehicle automatic transmission shift stage and outputs a corresponding signal to the transmission control unit 200.

In addition, the first shift control solenoid valve (SCSV_A) 140 and the second shift control solenoid valve (SCSV_B) 150 detect a current vehicle speed signal and output the same to the shift control unit 200. At this time, when the vehicle speed signal output by each of the shift control solenoid valves 140 and 150 is off or off, it is checked as 3 speed, and when it is on or on, it is checked as 1 speed.

4 is a view for explaining a variable stop deceleration control method of an automatic transmission vehicle according to the present invention.

Referring to FIG. 4, the output RPM of the automatic transmission is No2 and the turbine RPM is Nt2 at the first speed synchronizing time, and the time until the actual first speed synchronizing after the transmission signal from the third speed to the first speed is t and the output of the automatic transmission is t. If the rate of change of RPM is dNo / dt,

Because of to be.

As shown in the difference between the engine RPM and the turbine RPM at the first speed synchronizing point, it is called ΔN, and when this difference is kept below a certain level (A), it is caused by the synchronization generated when the speed is converted from the third speed to the first speed. Reduce shock levels with shifting.

That is, when the condition of DELTA N = N_e-Nt_2 ~ is satisfied, the shock due to the shift can be reduced.

When the above equations are arranged, the same result as in Equation 1 below can be obtained.

However, even if the above Equation 1 is used, when the initial shift from the third speed to the first speed may occur, a reaction force shock may occur due to a tip-in. It is preferable.

Where No1 is the 3-speed turbine RPM at the throttle control unit (TCU) command shift start point, Ne is the idle turbine RPM, Nt is the speed turbine turbine, No2 is the output RPM of the automatic transmission at 1-speed synchronization, and Nt2 is 1-speed synchronization The turbine RPM of the automatic transmission at time t, t is the time from the 3rd speed to the 1st speed, and the time from the actual 1st speed synchronization, and dNo / dt is the rate of change of the output RPM of the automatic transmission.

Using the above Equation 2, when shifting in the deceleration situation from the third to the first speed, the shift shock at the first speed synchronization point due to the tip-in shock due to the early shift and the shift delay can be reduced.

In the above description, the downshift shift control from the 3rd speed to the 1st speed before the automatic transmission is described as an example, but the present invention can also be applied to the downshift shifting control from the 2nd speed to the 1st speed before the automatic transmission is stopped.

Although the above has been described with reference to a preferred embodiment of the present invention, those skilled in the art will be able to variously modify and change the present invention without departing from the spirit and scope of the invention as set forth in the claims below. It will be appreciated.

As described above, according to the present invention, the difference between the engine RPM and the turbine RPM at the first speed synchronization point is output as a downshift shift control signal is output from the third speed to the first speed or the second speed to the first speed in the automatic transmission vehicle. By lowering the speed to below a certain level, even if the shift stage is controlled from the 3rd speed to the 1st speed or the 2nd speed to the 1st speed, the shift shock generated at the end of the shift can be reduced.

Claims (3)

(a) checking whether the first speed downshift shift control signal is output at the third or second speed before stopping when the driver releases the foot from the accelerator pedal while driving; (b) maintaining a difference between the engine RPM and the turbine RPM at a predetermined level or less at the first speed synchronizing time as the first speed downshift shift control signal is output at the third speed before stopping in the step (a); And (c) the automatic shift including the step of maintaining the difference between the engine RPM and the turbine RPM at a predetermined level or less at a first speed synchronizing time as the first speed downshift shift control signal is output at the second speed before stopping in the step (a); Deceleration control method before variable stop of vehicle. According to claim 1, wherein the three-speed turbine RPM at the start point of the shift control unit shift command to maintain below a certain level in step (b), Where Ne is the idle turbine RPM, dNo / dt is the rate of change of the output RPM of the automatic transmission, and t _{3-> 1} is the time from the 3rd to 1st speed signal to the actual 1st speed sync. Variable speed control before deceleration of the automatic transmission vehicle. According to claim 1, wherein the two-speed turbine RPM at the start point of the shift control unit shift command to maintain below a certain level in step (c), Where Ne is the idle turbine RPM, dNo / dt is the rate of change of the output RPM of the automatic transmission, and t _{2-> 1} is the time from the second speed to the first speed to the actual 1st speed synchronization. Variable speed control before deceleration of the automatic transmission vehicle.