KR100250295B1 - How to prevent uphill hunting - Google Patents

Abstract

The present invention relates to a method for preventing uphill hunting of an electronically controlled vehicle equipped with an automatic transmission.

The configuration of the present invention includes an input reading step of reading an engine torque, an engine speed, a turbine speed, an output shaft speed, a throttle opening degree, and a current shift stage; A weight gradient resistance calculation step of calculating force and acceleration acting on the difference and obtaining a current weight gradient resistance; A maximum vehicle speed determination step of determining whether the current vehicle speed is smaller than the maximum vehicle speed that can be achieved by the vehicle and ending at the maximum vehicle speed; A weight gradient resistance comparing step that compares the current weight gradient resistance with the minimum weight gradient resistance and terminates if it is not greater than the minimum weight gradient resistance; A torque calculation step of calculating the constant speed maintenance torque, then reading the downshift point at the current vehicle speed and calculating the engine torque of the downshift point; A torque comparing step of terminating when the constant speed maintenance torque is greater than the engine torque of the downshift point; An upshift prohibition step is performed to prohibit upshift.

The effect of this invention can provide the uphill hunting prevention method of the automatic transmission which improves operability by preventing frequent up or down shifts which are caused by lack of driving force at the high speed stage when trying to maintain the constant speed at the uphill.

Description

How to prevent uphill hunting

1 shows that the conventional automatic transmission vehicle hunting occurs uphill,

FIG. 2 shows obtaining the current weight gradient resistance in the uphill hunting prevention method according to the embodiment of the present invention.

3 shows whether vehicle speed maintenance torque is generated in an automatic transmission vehicle according to an embodiment of the present invention.

4 shows a change in engine torque according to an embodiment of this invention,

5 is a flowchart of a method for preventing uphill hunting of an automatic transmission vehicle according to an exemplary embodiment of the present invention.

6 is a flow chart for obtaining a local weight gradient resistance according to an embodiment of the present invention,

7 is a flow chart for calculating torque in accordance with an embodiment of this invention.

The present invention relates to a method for preventing uphill hunting, and more particularly, to a method for preventing uphill hunting for a vehicle equipped with an electronically controlled automatic transmission.

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

1 shows that hunting occurs in an uphill vehicle of a conventional automatic transmission.

The occurrence of uphill hunting in the conventional automatic transmission is as follows.

As shown in FIG. 1, when the driver attempts to drive uphill at a constant speed in a fixed change pattern region, the vehicle speed is reduced because the driving force is smaller than the driving resistance at the current shift stage, and the driver may use the accelerator pedal to maintain the vehicle speed. Will step on. Therefore, the vehicle is downshifted, and thus the vehicle accelerates again because the driving force is greater than the driving resistance. When the vehicle becomes larger than the desired vehicle speed, the driver releases the Excel again, thereby upshifting again. When the driving force is insufficient again, the vehicle speed decreases, and the driver repeats the process of down-shifting by stepping on the excel again. This phenomenon is called hunting.

However, when hunting occurs in the conventional automatic transmission described above, the state of the vehicle is not stabilized, the idle speed of the engine is not stabilized, and thus the driving speed is stopped or the guideline of the instrument is not stabilized. There is a floating problem.

Therefore, it is an object of the present invention to solve the above problems, and when trying to maintain a constant speed in the uphill of the automatic transmission that improves operability by preventing frequent up or down shifts caused by the lack of driving force in the high transmission stage. It is to provide a method for preventing uphill hunting.

As a means for achieving the above object, the configuration of the present invention,

An input reading step of reading an engine torque, an engine speed, a turbine speed, an output shaft speed, a throttle opening degree, and a current shift stage of the automatic transmission vehicle;

A weight gradient resistance calculation step of calculating force and acceleration acting on the difference and obtaining a current weight gradient resistance by the input read in the input reading step;

A maximum vehicle speed determination step of determining whether the current vehicle speed is smaller than the maximum vehicle speed that can be achieved by the vehicle and ending at the maximum vehicle speed;

A weight gradient resistance comparing step in which the current weight gradient resistance is compared with the minimum weight gradient resistance when the maximum vehicle speed determination step is not the maximum vehicle speed gradient, and ends if not greater than the minimum weight gradient resistance;

If the current weight gradient resistance is greater than the minimum weight gradient resistance in the above step of comparing the weight gradient resistance, calculate the constant speed maintenance torque, and then read the downshift point at the current vehicle speed and calculate the engine torque of the downshift point. step;

Comparing the constant speed maintenance torque with the engine torque of the downshift point, and ending the torque comparison step if the constant speed maintenance torque is greater than the engine torque of the downshift point;

In the torque comparison step, if the constant speed maintenance torque is not greater than the engine torque of the downshift point, an upshift prohibition step is performed.

Referring to the accompanying drawings, the most preferred embodiment which can easily implement this invention by the above structure is as follows.

FIG. 2 shows obtaining the current weight gradient resistance in the uphill hunting prevention method according to the embodiment of the present invention.

3 shows whether vehicle speed maintenance torque is generated in an automatic transmission vehicle according to an embodiment of the present invention.

4 shows a change in engine torque according to an embodiment of this invention,

5 is a flow chart of the uphill hunting prevention method of the automatic transmission vehicle according to an embodiment of the present invention,

6 is a flowchart for obtaining a current weight gradient resistance according to an embodiment of the present invention.

7 is a flow chart for calculating torque in accordance with an embodiment of this invention.

As shown in FIG. 5, the order of the uphill hunting prevention method according to the embodiment of the present invention is

To read the engine torque (T), engine speed (RPM) (Ne), turbine speed (Nt), output shaft speed (Output Shaft Speed), throttle opening (T _H ), and the current gear Input reading step 10;

The weight gradient resistance calculation step (20) calculates the force (F) and acceleration (a) acting on the difference and obtains the current weight gradient resistance (R _gc ) by the input read in the input reading step (10). );

A maximum vehicle speed determination step 30 determining whether the current vehicle speed V is smaller than the maximum vehicle speed V _max that the vehicle can produce and ending when the maximum vehicle speed V _max is reached;

When the maximum vehicle speed determination step 30 is not the maximum vehicle speed V _max , the current weight gradient resistance R _gc is compared with the minimum weight gradient resistance R _gmin , and is not greater than the minimum weight gradient resistance. A weight gradient resistance comparing step 40;

If the current weight gradient resistance R _gc is greater than the minimum weight gradient resistance R _{gmin in} the weight gradient resistance comparing step 40, the constant speed maintenance torque γ _M is calculated, and then at the current vehicle speed V, A torque calculation step 50 for reading a down shift point of the and calculating an engine torque γ _M of the down shift point;

Torque comparison step for comparing the engine torque (γ _A) of said constant speed maintaining torque (γ _M) and the down shift point, is greater than the constant-speed-holding torque (γ _M) is the engine torque (γ _A) of the down shift point end ( 60);

In the torque comparison step 60, if the constant speed maintenance torque γ _M is not greater than the engine torque γ _{A at the} downshift point, an upshift prohibition step 70 is performed to prohibit upshift.

In addition, with reference to Figure 6, the weight gradient resistance calculation step 20,

A force calculation step 21 acting on the car to obtain a force F acting on the car by multiplying the force F _E of the engine and the resistance force F _d transmitted to the wheel;

An acceleration calculation step (22) of obtaining a difference (F _E- F _d ) between the force of the engine and the resistance transmitted to the wheel, and dividing this value by the equivalent mass (M _e ) to obtain the acceleration (a) acting on the car;

Difference of air resistance (R _W ), rolling resistance (R _r ), product of equivalent mass and acceleration (M _e × a) from engine force (F _E ) transmitted to the wheel (F _E- R _r- R _W- By calculating M _e × a), the present weight gradient resistance calculation step 23 calculates the current weight gradient resistance R _gc .

In addition, with reference to Figure 7, the torque calculation step 50,

A constant speed maintenance torque calculation step 51 of calculating a constant speed maintenance torque that the vehicle can drive at constant speed from the current weight gradient resistance;

A downshift point reading step 52 of reading a current downshift point after the constant speed maintenance torque calculation;

The engine torque calculation step 53 calculates the engine torque of the current downshift point read in the downshift point reading step 52.

The uphill hunting prevention method of the automatic transmission vehicle according to the embodiment of the present invention by the above configuration is as follows.

In order to find the weight gradient resistance of the automatic transmission vehicle, first find the force (F) acting on the car.

F = F _E -F _d = M _e × a ‥‥‥‥‥‥‥‥‥‥ (1)

Where F _E is the force of the engine transmitted to the wheel, where F _E = (T-Te) × η _T × t _r × g _a × g _g / r _r, where T is the engine torque and η _T is The efficiency of each stage, t _r is the torque ratio, g _a is the gear ratio, g _g is the gear ratio of the gear, r _r is the tire radius, and T _e is the product of the engine inertia and engine speed change rate. In addition, M _e is the equivalent mass, a is the acceleration, and the resistance (F _d ) to prevent the progression of the car is given by (R _W + R _r + R _g ), R _W is the air resistance, R _r is the rolling resistance, R _g is the weight gradient resistance. In equation (1), acceleration a is

a = F _E / M _e -F _d / M _e ‥‥‥‥‥‥‥‥‥‥‥ (2)

And a graph of the force (F _E ) and acceleration (a) transmitted to the wheel is given as in FIG. Referring to FIG. 2, the current weight gradient resistance R _gc is obtained.

Rgc = F _E -R _r -R _W -M _e × a ‥‥‥‥‥‥‥‥‥‥ (3)

If the weight gradient resistance (R _g ) moves to the current weight gradient resistance (R _gc ), R _g = R _gc , and the current weight gradient resistance (R _gc ) is the minimum weight gradient resistance ( R _gmin ) is shown.

Next, to obtain the constant-speed-holding torque (γ _M), and the vehicle after obtaining the current weight gradient resistance (R _gc) to obtain the constant-speed holding torque that can drive the constant speed, that is, force for holding the vehicle speed (F _M )silver,

F _M = R _c + R _w + R _r ‥‥‥‥‥‥‥‥‥ 4

in,

F _M = γ _M × η _T × t _r × g _a × g _g / r _r ‥‥‥‥‥‥‥‥‥‥ (5)

In the end, the constant speed maintenance torque (γ _M ) is

γ _M = F _M / (η _T × t _r × g _a × g _g / r _r ) ‥‥‥‥‥‥‥‥‥‥ (6)

Becomes

In order to determine whether the constant speed maintenance torque γ _M is generated at the current shift stage, referring to FIG. 3, when the vehicle speed V is to be maintained, the current weight gradient resistance R _gc obtained above is obtained. ) And the constant speed holding torque (γ _M ) below the point A, the current shift stage may be kept as it is, but if the constant speed holding (γ _A ) exists at the point _A , the upshift is prohibited. The engine torque γ _A at point _A may be set to a value obtained by adding Δγ, which is a torque correction amount at the engine speed RPM in the current state, with reference to FIG. 4.

Referring to FIG. 5, in the input reading step 10, the engine torque T, the engine speed RPM Ne, the turbine speed Nt, and the output shaft speed of the automatic transmission vehicle are output. When the throttle opening degree (T _H ) and the current shift stage are read, the weight gradient resistance calculating step (20) is driven by the input (F) and acceleration acting on the vehicle by the input read in the input reading step (10). (a) is calculated, and the current weight gradient resistance (R _gc ) is obtained, and the product of the force (F _E ) and the resistance (F _d ) of the engine transmitted to the wheel in the force calculation step 21 acting on the car is calculated. By calculating the force (F) acting on the car, the difference between the engine force and the resistive force (F _E -F _d ) transmitted to the wheel in the acceleration calculation step 22 is obtained, and this value is again equivalent mass (Me). by dividing asking for acceleration (a) acting on the car, the current weight resistance gradient calculation step (23) of the air resistance (R _W) from the force (F _E) of the engine transmitted to the wheels, clouds Wherein _{(R r),} by obtaining the product of the equivalent mass and the acceleration difference _{(F E -R r -R W -M} e × a) of (M _e × a), rescued the current weight gradient resistance (R _gc) do. Next, the maximum vehicle speed determination step 30 determines whether the current vehicle speed V is smaller than the maximum vehicle speed V _max that the vehicle can produce, and terminates when the maximum vehicle speed V _max is reached. In 40), when the maximum vehicle speed V _max is not the maximum vehicle speed determination step 30 in the above step, the current weight gradient resistance R _gc is compared with the minimum weight gradient resistance R _gmin . If it is not greater than the resistance is terminated, the torque calculation step 50 is the constant speed maintenance torque (γ _A ) if the current weight gradient resistance (R _gc ) is greater than the minimum weight ratio resistance (R _gmin ) in the weight ratio resistance comparison step 40 above ), The downshift point at the current vehicle speed V is read, and the engine torque γ _A of the downshift point is calculated, i.e., in the constant speed maintenance torque calculation step 51 Calculate the constant speed maintenance torque that the vehicle can drive at constant speed from the current weight gradient resistance. In the shift point reading step 52, the current downshift point is read after the constant speed maintenance torque calculation, and the current downshift point read in the downshift point reading step 52 in the engine torque calculation step 53. The engine torque of is calculated.

Therefore, in the torque comparison step 60, the constant speed maintenance torque γ _M is compared with the engine torque γ _A of the downshift point, and the constant speed maintenance torque γ _M is the engine torque γ _A of the downshift point. If it is larger than the above, the upshift prohibition step 70, in the torque comparison step 60, if the constant speed holding torque γ _M is not greater than the engine torque γ _A of the downshift point, the upshift is performed. This prevents hunting of automatic transmission vehicles.

As a result, in order to prevent hunting caused by the uphill of a vehicle equipped with an automatic transmission, that is, to prevent shifting uniformly according to a fixed shift pattern, the current weight gradient resistance is obtained, and according to the calculated weight gradient resistance. If there is a point beyond the downshift line where the maximum torque at which the vehicle speed can be maintained is present and the maximum torque at the current shift stage is present, upshifting at the weight gradient resistance is prohibited.

Therefore, the effect of the present invention, which operates as described above, prevents frequent up or down shifts caused by the lack of driving force at the high shift stage when attempting to maintain a constant speed at an uphill, thereby preventing uphill hunting of an automatic transmission that improves operability. Can be provided.

Claims (3)

An input reading step of reading an engine torque, an engine speed, a turbine speed, an output shaft speed, a throttle cado, and a current shift stage of the automatic transmission vehicle; A weight gradient resistance calculation step of calculating force and acceleration acting on the difference and obtaining a current weight gradient resistance by the input read in the input reading step; A maximum vehicle speed determination step of determining whether the current vehicle speed is smaller than the maximum vehicle speed that can be achieved by the vehicle and ending at the maximum vehicle speed; A weight gradient resistance comparing step in which the current weight gradient resistance is compared with the minimum weight gradient resistance when the maximum vehicle speed determination step is not the maximum vehicle speed ratio, and ends when the maximum vehicle speed resistance is not greater than the minimum weight gradient resistance; In the above step of comparing the weight gradient resistance, if the current weight gradient resistance is greater than the minimum weight gradient resistance, the constant speed torque is calculated, and then the torque is calculated by reading the downshift point at the current vehicle speed and calculating the engine torque of the downshift point. step; Comparing the constant speed maintenance torque with the engine torque of the downshift point, and ending the torque comparison step if the constant speed maintenance torque is greater than the engine torque of the downshift point; The uphill hunting prevention method comprising the upshift prohibition step for prohibiting the upshift if the constant speed maintenance torque is not greater than the engine torque of the downshift point in the torque comparison step. The method of claim 1, wherein the step of calculating the weight gradient resistance, Calculating a force acting on the car to obtain a force (F) acting on the car by multiplying the force of the engine and the resistance delivered to the wheel; An acceleration calculation step of obtaining a difference between the force of the engine transmitted to the wheel and the resistance, and dividing this value by the equivalent mass to obtain the acceleration acting on the car; The current weight gradient resistance calculation step of calculating the current weight gradient resistance by calculating the difference between the product of air resistance, rolling resistance, equivalent mass and acceleration from the force of the engine transmitted to the wheels. . According to claim 1, wherein the torque calculation step, A dependent maintenance torque calculation step of calculating a constant speed maintenance torque that the vehicle can drive at constant speed from the current weight gradient resistance; A downshift point reading step of reading a current downshift point after the constant speed maintenance torque calculation; And an engine torque calculation step of calculating an engine torque of a current downshift point read in the downshift point reading step.