KR20000007740A - Speed change control method of automatic transmission for motor vehicle - Google Patents

Abstract

PURPOSE: A transmission control method of an automatic transmission for a motor vehicle is provided to improve the durability and the transmission quality of the automatic transmission. CONSTITUTION: A transmission control method comprises the steps of:using the rotating speed(rpm) and the speed of a vehicle at power off up shift transmission by an automatic transmission without a turbine rpm sensor or an input speed sensor; increasing the change of the rotating speed of an engine by promoting the duty output to a line pressure solenoid valve at the beginning of the transmission; reducing the combining shock by decreasing the change of the rotating speed of the engine at the last stage of the transmission; and controlling the transmission time.

Description

Shift control method of automatic transmission for vehicle

The present invention relates to a shift control method of an automatic transmission for a vehicle. More particularly, the engine rotational speed during power-off upshift shifting in a vehicle automatic transmission without a turbine rotational speed sensor or an input speed sensor is described. Determination of the end point of the shift using rpm) and the vehicle speed, and duty correction during shifting, increase the duty output to the line pressure solenoid valve at the beginning of shifting to increase the change in engine speed, and reduce the rate of change of engine speed at the end of shifting The present invention relates to a shift control method of an automatic transmission for a vehicle that reduces shock and improves shift time, thereby improving durability and shift quality of the automatic transmission.

As is well known, an example of an automatic transmission for a vehicle interacts with an engine 20 and an automatic transmission electronic control device 30 (TCU; hereinafter referred to as 'TCU') as schematically shown in block diagram in FIG. 1. To work. As shown in FIG. 1, the engine 20 transmits various signals, for example, an engine speed signal and a throttle opening signal, to the TCU 30 through an engine electronic control unit (ECU) 40. It provides the engine speed and idle switch signal directly to the automatic transmission 10 and the TCU 30, respectively, the TCU 30 also various signals such as duty signal for the operation of the line pressure solenoid valve To the automatic transmission 10. The automatic transmission 10 having received the various signals as described above outputs a predetermined vehicle speed signal, and the vehicle speed signal is fed back to the TCU 30.

Referring to FIG. 1, the hydraulic pressure generated by the line pressure solenoid duty signal during the shifting acts on the actuating clutch of the automatic transmission 10 to cause a change in the angular velocity of the operating element in the automatic transmission. (rpm) change, and also the change in the speed of the torque converter affects the engine speed.

As shown in FIG. 1, in the case of an automatic transmission without a turbine rpm sensor or an input speed sensor, the determination of the shift start point and the shift end point is simply performed by experience or experiment. (Map) Sequential control by value and time.

Therefore, the problem caused by this is that the shift start point and the shift end point are simple map values, so that accurate determination is impossible, and thus, there is a high possibility of the initial engagement shock and the late engagement shock of the clutch or brake.

In addition, it is most preferable that the inertia phase start point becomes the total control start point when the total control between the automatic transmission and the engine is applied. Ending the total control at the completion of synchronization does not affect the power performance of the vehicle. In the prior art, when there is no turbine rotational speed sensor or input speed sensor, only the stored map value is controlled without grasping the state in the transmission during shifting, so the possibility of shift shock increases when the situation is not right. There was this.

The present invention has been made to solve the above problems, and the engine rotation speed (rpm) and the power off (up-shift) shift in a vehicle automatic transmission without a turbine rotational speed sensor or an input speed sensor and Determination of the end point of shifting by using the vehicle speed and duty correction during shifting, increase the duty output to the line pressure solenoid valve at the beginning of shifting to increase engine speed change, and at the end of shifting, reduce the rate of change of engine speed to reduce end-coupled impact The purpose of the present invention is to provide a shift control method of an automatic transmission for a vehicle, which improves durability and shift quality of the automatic transmission by adjusting the shift time.

Another object of the present invention is to provide a shift control method of an automatic transmission for a vehicle to reduce shift shock and shift time by shifting and controlling the front and rear portions of a shift section during shifting.

Another object of the present invention is to provide a shift control method of an automatic transmission for a vehicle in which durability of a clutch and a brake is improved by adjusting a target slip amount and a shift time.

It is another object of the present invention to provide a shift control method of an automatic transmission for a vehicle to accurately determine a shift end point and perform appropriate control thereof to eliminate a late coupling shock of a clutch or a brake.

1 is a schematic block diagram of a power train system related to an automatic transmission for a vehicle to which the present invention is applied;

2 is a flowchart of a shift control method of an automatic transmission for a vehicle according to the present invention;

3 and 4 are graphs of the line pressure solenoid valve duty control during power off upshift shifting achieved by the present invention.

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

10: automatic transmission 20: engine

30: TCU (transmission control unit) 40: Engine Electronic Control Unit (ECU)

Shift control method of the automatic transmission for a vehicle according to the present invention to achieve the above object,

In the shift control method of an automatic transmission for a vehicle without a sensor for detecting the turbine rotational speed,

The vehicle speed is defined as vehicle_speed, the current gear ratio is current_gear, the engine speed input from the engine electronic controller is eng_rpm, the engine speed change rate (m / sec ² ) is dot_eng_rpm, the safety factor is s_factor, The main loop period is main_loop_time, the constant value is N, and the synchronous completion (shift completion) determination Δ If you define it as Nsf,

The shift completion determination in the inertia phase section, which is the actual shift section (c section), is characterized in that it satisfies the following formula.

Δ Nsf = | vehicle_speed × current_gear-eng_rpm |

dot_eng_rpm ≤ s_factor × Δ (vehicle_speed-last_vehicle_speed) × 1000 / main_loop_time

In the preferred embodiment of the present invention, the synchronization completion determination is not performed during the N periods after the start of the torque phase section (b section) in which there is no change in the engine rotation speed but only a torque change.

In a preferred embodiment of the present invention, the correction output duty in the torque phase section,

Reducing the target slip amount to 0 rpm during the following time from the time when the target slip amount So is 120 rpm and the actual slip amount becomes 270 rpm or less;

t_target = t_goal-the time from the start of section b until the actual slip is 270 rpm,

X = 120 / (t_target / main_loop_time),

Not changing the target slip amount until the actual slip amount is 270 rpm;

When the actual slip amount falls below 270 rpm, the target slip amount is 120-X * J;

Formula; S = | eng_rpm-vehicle_speed * current_gear- Δ Nsf |

Sh = S + filter_factor * (S-last_S)

b interval output duty = last_D-rmap_Dboff + Dbloff;

In a preferred embodiment of the present invention, when the actual slip amount is 120 rpm or less after the start of the section b, the actual slip amount is regarded as the target slip amount.

Hereinafter, a preferred embodiment of a shift control method of an automatic transmission for a vehicle according to the present invention will be described in detail with reference to the accompanying drawings.

First, it will be apparent to those skilled in the art that the shift control method for an automatic transmission for a vehicle according to the present invention will be programmed and used for recording and storing in the TCU 30 mentioned in FIG. The shift control method of the vehicular automatic transmission according to the present invention is preferably applied at the time of power-off upshift shifting. In addition, the shift control method of the automatic transmission for a vehicle according to the present invention is preferably applied to an automatic transmission for a vehicle in which a turbine rotational speed sensor or an input speed sensor is not applied.

2 is a flowchart of the shift control method of the present invention, and FIGS. 3 and 4 are graphs related to the line pressure solenoid valve duty control during power-off shift shifting achieved by the present invention. In FIG. 4, section a is a clutch fill section for moving the clearance part of the clutch to a high pressure, section b is a torque phase section without torque change, and section c is an inertia phase as an actual shift section. It is a section. In FIG. 4, the symbol SS denotes a shift start, IF denotes an initial finish, IB denotes an inertia bigin, and SF denotes a shift finish.

Referring to FIG. 1, this is a schematic block diagram of hardware to which the present invention is applied, and elements input to the TCU 30 are an idle switch signal, an engine rpm signal, a throttle opening signal, an oil temperature and a vehicle speed signal, and an output element. Solenoid valve duty signal. Here, the throttle opening degree and the idle switch signal is used as a reference value for determining power on / off, the oil temperature is used as a reference value for correcting the duty output to the line pressure solenoid valve, the engine rpm and the vehicle speed signal is a shift control method of the present invention. It is used directly in shifting, and it is used for shift compensation and shift end determination. In addition, the shift solenoid valves A and B of the output elements are turned on or off appropriately for the shift stage, the overrun clutch solenoid is turned off, and the value calculated by the TCU 30 at the time of shifting is converted to the line pressure. Output to solenoid valve.

In the shift control method of the present invention, which is preferably applied to the hardware block diagram as described above, the vehicle speed is defined as vehicle_speed, the current gear ratio is represented by current_gear, and the engine rotational speed input from the ECU 40 is represented by eng_rpm. Rotational speed change rate (m / sec ² ) to dot_eng_rpm, safety factor to s_factor, program main loop period to main_loop_time, constant value to N, synchronization completion (shift completion) determination Rotational speed Δ If it is defined as Nsf, the shift completion determination in the inertia phase section, which is the actual shift section (c section), is determined by the formula;

Δ Nsf = | vehicle_speed × current_gear-eng_rpm |

dot_eng_rpm ≤ s_factor × Δ (vehicle_speed-last_vehicle_speed) × 1000 / main_loop_time; If it satisfies.

That is, in FIG. 2, when the shift section of the automatic transmission 10 is the c section, which is the actual shift section, and the program calculation period is more than N cycles (S1) (S2), the TCU 30 synchronizes with the above formula (shifting) Completion determination engine rpm is calculated and applied to the automatic transmission 10 (S3). At this time, the TCU 30 does not make a synchronization completion determination during the N period after the start of the torque phase section (b section), in which there is no engine rpm change and only a torque change.

If the program calculation cycle was less than N cycles in step S2, the TCU 30 formulates a vehicle speed change rate (dot_vehicle_speed);

dot_vehicle_speed = s_factor * | vehicle_speed-last_vehicle_speed | * 1000 / main_loop_time; It calculates by (S11) and compares the calculated vehicle speed change rate (dot_vehicle_speed) with the engine rpm change rate (dot_eng_rpm) (S12).

When the engine rpm change rate exceeds the vehicle speed change rate in step S12, the TCU 30 corrects the output duty in the b section, which will be described in detail with reference to FIGS. 3 and 4.

3 and 4 are graphs related to the duty control of the line pressure solenoid valve at the time of shifting.

If the engine rpm change rate exceeds the vehicle speed change rate in step S12, the TCU 30 is formulated; S = | eng_rpm-vehicle_speed * current_gear- Δ Nsf | ,

Calculate Sh = S + filter_factor * (S-last_S);

After performing step S13, the TCU 30 checks the change state of the target slip amount So through steps S14 to S17.

Then, the target slip amount is 120rpm, and the target slip amount is decreased to 0rpm during the time according to the following formula from the time when the actual slip amount becomes 270rpm or less,

t_target = t_goal—the time from the start of section b until the actual amount of slip reaches 270 rpm;

X = 120 / (t_target / main_loop_time);

The target slip amount is set to 120-X * J when the actual slip amount falls below 270 rpm without changing the target slip amount until the actual slip amount drops below 270 rpm (S18). In step S18, J is a constant. When the actual slip amount is 120 rpm or less after the start of the b section in step S18, the actual slip amount is regarded as the target slip amount and control is performed.

After step S18, the TCU 30 finds a ramp_Dbloff value corresponding to the graphs illustrated in FIGS. 3 and 4, that is, a Sh / So value (S19). After the ramp_Dbloff value is found in step S19, the TCU 30 performs a formula;

Computing b section output duty = last_D-ramp_Dboff + Dbloff; and shift control is performed through the calculated b section output duty value (S20).

Thus, according to the present invention, the shift shock at the time of power-off shift shift can be reduced, and the shift time can be reduced.

As described above, the shift control method for an automatic transmission for a vehicle according to the present invention includes an engine rotational speed during power-off upshift shifting in a vehicle automatic transmission without a turbine rotational speed sensor or an input speed sensor. Determination of the end point of the shift using rpm) and the vehicle speed, and duty correction during shifting, increase the duty output to the line pressure solenoid valve at the beginning of shifting to increase the change in engine speed, and reduce the rate of change of engine speed at the end of shifting By reducing the impact and adjusting the shift time, it provides the advantage of improving the durability and shift quality of the automatic transmission.

The invention is not limited to the embodiments described herein, but may be modified and changed by those skilled in the art without departing from the spirit and scope described in the appended claims.

Claims (4)

In the shift control method of an automatic transmission for a vehicle without a sensor for detecting the turbine rotational speed, The vehicle speed is defined as vehicle_speed, the current gear ratio is current_gear, the engine speed input from the engine electronic controller is eng_rpm, the engine speed change rate (m / sec ² ) is dot_eng_rpm, the safety factor is s_factor, The main loop period is main_loop_time, the constant value is N, and the synchronous completion (shift completion) determination Δ If you define it as Nsf, The shift completion determination in the inertia phase section, which is the actual shift section (c section), is determined by the formula; Δ Nsf = | vehicle_speed × current_gear-eng_rpm | , dot_eng_rpm ≤ s_factor × Δ (vehicle_speed-last_vehicle_speed) × 1000 / main_loop_time, when the shift control method for an automatic transmission for a vehicle, characterized in that the case. 2. The shift control method of claim 1, wherein the determination of synchronization completion is not performed during the N periods after the start of the torque phase section (b section), in which there is no change in the engine rotation speed and only the torque change. The correction output duty of the torque phase section in accordance with claim 1 or 2, Reducing the target slip amount to 0 rpm during the following time from the time when the target slip amount So is 120 rpm and the actual slip amount becomes 270 rpm or less; t_target = t_goal-the time from the start of section b until the actual slip is 270 rpm, X = 120 / (t_target / main_loop_time), Not changing the target slip amount until the actual slip amount is 270 rpm; When the actual slip amount falls below 270 rpm, the target slip amount is 120-X * J; Formula; S = | eng_rpm-vehicle_speed * current_gear- Δ Nsf | Sh = S + filter_factor * (S-last_S) b section output duty = last_D-rmap_Dboff + Dbloff, wherein the shift control method of the automatic transmission for a vehicle is obtained. 4. The shift control method according to claim 3, wherein the actual slip amount is regarded as a target slip amount when the actual slip amount after the start of the b section is equal to or less than 120 rpm.