KR100293674B1 - Method for controlling kick down shifting from 4-range to 3-range - Google Patents

Abstract

PURPOSE: A control method of kick down shifting from the 4-range to the 3-range is provided to reduce shift shock, and to improve driving experience by stabilizing synchronized shifting with regulating the increase of turbine RPM(Revolution Per Minute) at power off. CONSTITUTION: A TCU(Transmission Control Unit) detects power-on kick down shifting from 4-range to 3-range in stepping an accelerator pedal(S100,S110), and outputs a feedback 4 to 3 down shift duty control to a driving unit(S120). The output of a duty control signal for shifting to the desired speed range is decided, and power-off is detected in operating the accelerator again(S130,140). The TCU outputs the duty signal to the driving unit to increase pressure of a front clutch at power-off(S150,S160), and applies the duty to the driving unit to decrease hydraulic pressure for preventing shock of the front clutch(S170). The TCU reduces the duty value with the predetermined gradient(S190). Shifting is finished in keeping turbine RPM constantly after deciding first synchronized shifting, and second synchronized shifting is decided in changing the turbine RPM. Shift shock is reduced, and driving experience is improved with stabilizing kick down shifting from the 4-range to the 3-range.

Description

Kickdown 4 → 3 Downshift Shift Control

The present invention relates to an automatic transmission, and more particularly, to reduce the occurrence of a shift shock due to a driver's accelerator pedal re-operation during a kick-down 4 → 3 downshift shift by the driver's accelerator pedal operation for an acceleration drive during a four-speed drive. Kickdown for 4 → 3 shift control method.

In general, if the driver operates the accelerator pedal for acceleration multiplication during four-speed driving in a vehicle equipped with an automatic transmission, the shift control device (hereinafter referred to as TCU) performs the kick-down power-on-down shift shifting according to the shift pattern stored in the memory. The engine's power was increased to increase the vehicle's traveling speed.

Therefore, in the automatic transmission operating as described above, a kick-down 4 → 3 downshift shift control signal is output according to the driver's accelerator pedal operation during the four-speed driving, and the driver shifts the accelerator pedal after shifting the shift stage to the target shift stage. When the power condition is changed from the power on to the power off, conventionally, the power-off 4 → 3 downshift shift control duty is output. When the shift synchronization is determined, the shift is reduced by a predetermined duty and shift control is performed at a predetermined slope.

However, in the above conventional technology, when the driver outputs the kick-down 4 → 3 shifting signal and actually shifts the shift stage to the target shift stage, and the driver turns off the accelerator pedal again, the power condition is changed from power on to off and power off. As the 4 → 3 downshift shift control signal is output, the turbine rpm (Nt), which has been rising in release, is lowered again due to a decrease in input. At this time, the control pressure of the front clutch (F / C) is used. As a result, the turbine rpm (Nt) is quickly synchronized to three speeds, resulting in a shift shock, and there is a problem that adversely affects the shift response.

Accordingly, an object of the present invention is to solve the above problems, the output of the kick-down 4 → 3 downshift shifting control signal during the four-speed drive, the shift to the actual gear shift stage to the feed-back 4 → 3 downshift shifting When the power condition is changed from power on to power off by the driver's accelerator pedal operation, the increase of the turbine rpm (Nt) is controlled by the front clutch (F / C) to stabilize the kick-down 4 → 3 downshift shifting synchronization. It is to provide a kick-down 4 → 3 downshift shift control method of completing a shift.

1 is a block diagram of a kick-down 4 → 3 downshift shift control apparatus according to an embodiment of the present invention,

2 (a) and (b) is a flow chart of the kick-down 4 → 3 downshift shift control operation according to an embodiment of the present invention,

3 is a kick down 4 to 3 downshift shift control duty pattern diagram according to an exemplary embodiment of the present invention.

The present invention for achieving the above object, the feedback 4 → 3 downshift shift control signal stored in the memory when the driver operates the accelerator pedal to satisfy the power-on kick-down 4 → 3 downshift shifting conditions during the four-speed driving Outputting; In this step, the power condition according to the driver's accelerator pedal is changed to power-off after outputting a duty return control signal for outputting the feed back 4 → 3 downshift shift control signal to output the shift stage to the target shift stage. Determining whether it has been made; In the above step, if the duty condition for actually shifting the shift stage to the target shift stage is output, and the power condition according to the driver's accelerator pedal re-operation is changed to the power-off, the duty Df2 is changed for a predetermined time T2. Outputting a duty to a predetermined value D2 to reduce the output of the line pressure when a predetermined time T2 elapses; In this step, when a predetermined time T2 has elapsed, the engagement duty D2 is output to reduce the output of the line pressure, and the engagement duty is maintained at a constant slope for a predetermined time T to temporarily stop the transmission transmission completion determination. Outputting (D2); Reducing the engagement duty (D2) to a predetermined predetermined slope (A1% / sec) when a predetermined time (T) for temporarily stopping the transmission transmission completion determination in the above step is output; Determining whether the primary transmission is completed by reducing the engagement duty D2 to a predetermined predetermined slope (A1% / sec) in the step; When the first shift synchronization is completed in the step, it is determined whether the predetermined time (T2) has elapsed, and if the predetermined time (T2) has elapsed in the above comprises the step of ending all duty control and returning to the main It features.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention, which can be achieved and realized in detail by the above objects, will be described in detail with reference to the accompanying drawings.

As illustrated in FIG. 1, the configuration of the kick-down 4 to 3 downshift shift control apparatus according to an exemplary embodiment of the present invention detects a signal that is variable according to a driving state of the vehicle and outputs a corresponding electric signal. State sensing means 10; After receiving the electric signal output from the vehicle driving state sensing means 10, the driver shifts the power-on kick-down according to the driver's accelerator pedal operation during the 4th speed driving. A TCU 20 for outputting a predetermined duty control signal stored in the memory when the power condition is changed to the power-off according to the accelerator pedal re-operation of the controller; The driving unit 30 is configured to receive a shift duty control signal output from the TCU 20 and perform power-on 2 → 3 upshift shifting.

In the above configuration, the vehicle driving detection means 10 includes a throttle valve opening degree detection unit 11 for detecting the opening degree of the throttle valve whose opening and closing state is variable in conjunction with the operation state of the accelerator pedal and outputting a corresponding signal; A vehicle speed detector 12 which detects an output shaft rotational speed of the vehicle and outputs a corresponding signal corresponding to the traveling speed of the vehicle; A turbine shaft rotation speed sensing unit 13 for sensing a rotation speed of the turbine shaft of the torque converter connected to the input shaft of the transmission and outputting a corresponding signal; An engine rotation speed detection unit 14 for detecting a rotation speed of the crankshaft which is varied according to an operating state of the engine and outputting a corresponding signal; A shift stage detecting unit 15 configured to detect a variable state of the shift stage and output a corresponding signal when the shift stage is changed according to the throttle valve opening amount and the vehicle speed; And a kick down switch 16 for detecting an operation state of the kick down servo and outputting a predetermined electric signal.

The operation state of the kick-down 4 to 3 downshift shift control method made by the above configuration will be described with reference to FIG.

When the driver manipulates the accelerator pedal to increase the acceleration while driving the vehicle at four speeds, the TCU 20 determines whether the power-on kick-down 4 → 3 downshift shift condition is performed (S100 and S110).

When the shift condition according to the driver's accelerator pedal operation is the power-on kick-down 4 → 3 downshift shift condition, the TCU 20 drives the feedback 4 → 3 downshift shift duty control signal stored in the memory. Output to 30 (S120).

In response to the output of the feed back 4? 3 downshift shift duty control signal, the actuator as the driving means 30 releases the 4 speed pressure and supplies the 3 speed pressure output from the oil pump to the friction elements of the predetermined clutch and brake.

In operation S130, it is determined whether a duty control signal Du4 for actually shifting the shift stage to the target shift stage is output as the output of the kick-down 4? 3 downshift shift control signal.

When the driver's accelerator pedal is re-manufactured after the duty control signal Du4 is outputted to the output shift of the kick-down 4 → 3 downshift shift control signal to output the shift to the target shift stage (S, B). The TCU 20 determines whether the power condition is changed to power off (S140).

When the duty control signal Du4 is not output in the duty control signal Du4 output determination step S130 or when it is determined that the power control variable is not changed to power off in the power off variable determination step S140, the duty control is performed. The third speed pressure supply step S120 is performed such that the third speed pressure can be maintained until the signal Du4 is outputted and changed to power off.

When the power condition by the driver's accelerator pedal re-operation is changed to the power-off, the TCU 20 is predetermined to increase the pressure of the front clutch F / C for a predetermined time T2 as shown in FIG. 2A. The duty Df2 is outputted to the driving means 30 (S150 and S160).

The TCU 20 outputs a duty Df2 control signal for raising the front clutch F / C pressure for the predetermined time T2 to the driving means 30, and the predetermined time T2 elapses. After that, in order to prevent the engagement shock of the front clutch F / C, the duty D2 for reducing the oil pressure supplied to the front clutch F / C is output to the driving means 30 (S170).

As described above, the duty cycle D2 for reducing the hydraulic pressure supplied to the front clutch F / C is output to prevent engagement shock of the front clutch F / C, so that the TCU 20 prohibits the shift synchronization completion determination. In order to output the duty D2 uniformly for a predetermined time T (S170, S180), when the predetermined time T has elapsed, the duty D2 at a predetermined slope (A1% / sec) The value is reduced and output to the driving means 30 (S190).

Therefore, the actuator, which is the driving means 30, gradually engages the front clutch F / C according to the output duty control signal, and accordingly, the TCU 20 determines whether the shift stage is synchronized to the third speed, which is the target shift stage. (S200).

The method of determining whether the primary transmission is completed in the third speed, in which the shift stage is the target shift stage, may be determined by Equation 1 below.

[Equation 1]

|No - Nt|Nts1

| No-Nt |

(In the above, Nts1 is the change amount of the turbine rpm to be detected, and | No-Nt | is the reference value of the completion point of the primary transmission.)

If it is determined in the third speed synchronization completion step (S200) that the primary transmission is not completed at the third speed, the process proceeds to the duty (Df2) output stage (S150).

When the primary transmission is completed at the third speed, in which the shift stage is the target shift stage, the TCU 20 determines whether a predetermined time T3 has elapsed (S210), and when the predetermined time T3 has elapsed. End all shift control.

When the predetermined time T3 has not elapsed in the determination S210, it is determined whether the turbine rpm has fallen below the predetermined reference value Nt3 (S220).

If the turbine rpm does not fall below the predetermined reference value Nt3 in the determination S220, the process proceeds to the duty output step S190 to adjust the duty D2 value at the predetermined slope A1% / sec. Keep printing.

If the determination (S220) falls below the predetermined reference value (Nt3) to the turbine rpm, the TCU 20 continues to output the duty (D2) value at a predetermined slope (A1% / sec) (S230), and the speed change stage In operation S240, it is determined whether the secondary transmission is completed in the third speed which is the speed change stage.

In the determination step (S240), a method of determining that the second transmission is completed at the third speed, in which the shift stage is the target shift stage, may be determined by Equation 2 below.

[Equation 2]

|No - Nt|NtS2

| No-Nt |

(In the above, Nts2 is the change value of the turbine rpm, and | No-Nt | is the reference value of the secondary transmission completion point.)

If the secondary transmission is not completed in the target shift stage in the determination step (S240), the duty (D2) output step (S230) to continue the output of the duty (D2) until the secondary transmission is completed. Proceed to

In the above, when the second gear shift is completed to the target shift gear, the TCU 20 performs a predetermined inclination (A1% /) for a predetermined time T4 for the third speed pressure to completely fill the front clutch F / C. In order to output the duty D2 value to the driving means 30 in sec), it is determined whether the predetermined time T4 has elapsed (S250).

When the predetermined time T4 has elapsed in the determination S250, all duty control ends and returns to the main.

When the predetermined time T4 for completely filling the three-speed pressure in the front clutch F / C has not elapsed, the TCU 20 sets the duty D2 at a predetermined inclination (A1% / sec). The duty (D2) output step (S230) proceeds to output to the drive means 30 until the vehicle transmission is completed.

The above embodiments are described as the most preferred embodiments, and the present invention is not limited thereto, and the embodiments can be easily described from the above embodiments.

As described above, in the embodiment of the present invention, if the power stage according to the accelerator pedal operation of the driver is changed to the power-off after the shift stage is actually shifted to the target shift stage during power-on kick-down 4 → 3 downshift shifting, the corresponding memory is stored in the corresponding memory. After outputting the predetermined duty control signal, it is determined that the primary transmission is completed. If there is no change in the rpm of the turbine for a predetermined time, the shift is completed. If the rpm of the turbine is changed for a predetermined time or more, the secondary By performing the synchronous determination, the shift-down of the downshift 4 → 3 downshift of the shift stage is completed stably, thereby reducing the shift shock, improving the feeling of shifting and improving the riding comfort.

Claims (4)

In the shift control method of the automatic transmission, when the driver operates the accelerator pedal during four-speed driving and satisfies the power-on kick-down 4 → 3 downshift shifting condition, the feedback 4 → 3 downshift shift control signal stored in the memory is output. Making a step; In this step, the power condition according to the driver's accelerator pedal is changed to power-off after outputting a duty return control signal for outputting the feed back 4 → 3 downshift shift control signal to output the shift stage to the target shift stage. Determining whether it has been made; In the above step, if the duty condition for actually shifting the shift stage to the target shift stage is output, and the power condition according to the driver's accelerator pedal re-operation is changed to the power-off, the duty Df2 is changed for a predetermined time T2. Outputting a duty to a predetermined value D2 to reduce the output of the line pressure when a predetermined time T2 elapses; In this step, when a predetermined time T2 has elapsed, the engagement duty D2 is output to reduce the output of the line pressure, and the engagement duty is maintained at a constant slope for a predetermined time T to temporarily stop the transmission transmission completion determination. Outputting (D2); Reducing the engagement duty (D2) to a predetermined predetermined slope (A1% / sec) when a predetermined time (T) for temporarily stopping the transmission transmission completion determination in the above step is output; Determining whether the primary transmission is completed by reducing the engagement duty D2 to a predetermined predetermined slope (A1% / sec) in the step; When the first shift synchronization is completed in the step, it is determined whether the predetermined time (T2) has elapsed, and if the predetermined time (T2) has elapsed above, the step of ending all the duty control and return to the main A kickdown 4 to 3 downshift shift control method characterized by the above-mentioned. 2. The engagement duty D2 of claim 1, wherein when the turbine rpm Nt decreases below the predetermined reference value Nt3 in a state where the predetermined time T2 has not elapsed, the engagement duty D2 is continuously output at a predetermined slope A1% sec. Determining whether the second gear shift is completed to the target gear shift by the gear shift stage; In this step, if it is determined that the secondary transmission is completed as the target shift stage, the kick-down 4 → 3 downshift shift control including ending all duty control and returning to the main after a predetermined time T4 has elapsed. Way. The method of claim 2, wherein the method of determining whether the second gear shift is completed to the target gear is included as determined by Equation 2 below. (Equation 2) NtS2

| No-Nt | (Nts2 is a change value of the turbine rpm, and | No-Nt | is a secondary synchronization determination reference value.) The method of claim 1, wherein the method of determining whether the speed change stage is completed in the first speed shift gear at the third speed, which is the target speed change speed, is determined by Equation 1 below. (Equation 1) Nts1

| No-Nt | (In the above, Nts1 is the change amount of the turbine rpm, and | No-Nt | is the primary shift synchronous completion judgment reference value.)

Images