KR102213252B1 - Torque control method - Google Patents

Abstract

Disclosed is a torque control method. According to the present invention, the torque control method comprises: a step of checking the acceleration volition of a driver; a step of outputting a primary time constant (T1_Temp) value for filtering driver demand torque if the acceleration volition of the driver is checked; a step of determining whether an accelerator pedal opening degree change rate (α) exceeds a determination reference value; and a step of starting a correction process to correct the primary time constant (T1_Temp) value if the accelerator pedal opening degree change rate (α) exceeds the determination reference value, and filtering the driver demand torque with a filter time constant after the correction to calculate final target torque. The present invention improves a calculation method of a correction coefficient (k) for determining torque filtering responsiveness to sufficiently reflect the acceleration volition of a driver in accordance with various acceleration situations such as LTI, MTI, FTI, etc.

Description

Torque control method}

The present invention relates to a vehicle torque control method, and more particularly, to a torque control method in which a driver's acceleration intention can be sufficiently reflected by improving a calculation method of a correction factor k for determining torque filtering responsiveness.

In general, when the accelerator pedal is operated while driving a vehicle, a corresponding driver's required torque is determined, and engine output is controlled according to the determined required torque. When the driver's required torque is generated by the accelerator pedal operation, the filter is passed through the filter without making it the final target torque. This is to alleviate the surge and shock that the driver receives due to sudden torque fluctuations.

That is, the engine does not output all of the torque requested by the driver when the accelerator pedal is stepped on, and uses the value filtered by the low-pass filter. The vehicle's torque filtering responsiveness is controlled by the time constant T1 (the time to reach the torque requested by the driver), and T1 is a value between 0 and 1, and the responsiveness of the filter improves as it approaches 0. In other words, as the time constant T1 approaches 0, the oscillation delay decreases.

1 is a schematic diagram for explaining the torque filtering concept according to the prior art, in which the change of the initial driver's required torque (Nm) and the time constant are reflected when the accelerator pedal changes (at the time of rapid acceleration), that is, the final target torque (Nm) after filtering It is a diagram showing the change of.

In Fig. 1, S1 represents the change in the initial driver's required torque according to the driver's rapid acceleration operation, and S2 is the final target torque output after the first low pass filtering for the initial driver's required torque when the time constant T1 is 0.1 (T1 = 0.1). It is a curve showing the change and S3 represents the final target torque change by filtering the driver's required torque by applying the time constant T1 to 0.2 (T1 = 0.2), and S4 represents the change in accelerator pedal opening (%).

1, it can be seen that the final target torque S2 reflecting the relatively small time constant T1 is closer to the initial driver requested torque S1 than the final target torque S3 reflecting the relatively large time constant T1. . In other words, the smaller the time constant T1 is, the closer the final target torque is to the initial driver's required torque, which means that the driver's willingness to accelerate is reflected in the engine output.

In the prior art, the time constant T1 is determined by multiplying the T1_Temp value output from the characteristic map using the gear ratio and engine speed as a factor, and the one-dimensional curve correction factor k using the accelerator pedal opening degree change rate (%/s) as a factor ( T1 = T1_Temp * k). As such, the conventional T1 is affected by the correction factor k, which takes the rate of change of the accelerator pedal opening as a factor. However, there is a blind spot in that the correction factor k is applied only when a change in accelerator pedal opening is detected.

For example, when the driver makes a fast tip in (FTI) (when the accelerator pedal is rapidly pressed to 100%), only the moment when the accelerator pedal opening changes from 0 to 100%, that is, the moment when the accelerator pedal change is detected. A correction factor k is applied to T1, and while the vehicle starts after the accelerator pedal opening reaches 100%, it has the same T1 as in the case of LTI (Low tip in) and MTI (Medium tip in).

For reference, LTI (Low tip in) and MTI (Medium tip in) mean that the pedal is pressed up to 100% with relatively gentle acceleration compared to FTI (Fast tip in), and the correction factor k is a step function It is the amount of fluctuation of initial torque.

That is, even in the conventional case of oscillation in various cases of LTI, MTI, and FTI, the correction factor k is applied to the time constant T1 only for a short moment when the accelerator pedal change is detected, and after the accelerator pedal opening is stabilized, the same filter response is obtained. Therefore, there is no significant difference in the final target torque, and therefore, even if the driver wants to accelerate rapidly while taking into account the surge, there is a problem that it is not properly reflected in the torque.

Korean Patent Publication No. 2013-0045100 (Publication date 2013.05.03)

The technical problem to be solved by the present invention is to provide a torque control method that can reflect the driver's acceleration will in various starting situations such as LTI, MTI, and FTI by improving the calculation method of the correction factor k that determines the torque filtering responsiveness. I want to provide.

According to an embodiment of the present invention as a means of solving the problem,

a) checking the driver's willingness to accelerate;

b) outputting a first time constant T1_Temp for filtering the driver requested torque when the driver's intention to accelerate is confirmed;

c) determining whether the accelerator pedal opening degree change rate α exceeds the determination reference value; And

d) If the accelerator pedal opening degree change rate (α) exceeds the judgment reference value, the correction process is started to correct the first time constant T1_Temp value, and the final target torque is calculated by filtering the driver's torque required by the filter time constant after the correction. It provides a torque control method comprising a;

Here, in step a), if the gear is located in the D (Drive) stage and the accelerator pedal opening (APS) is greater than 0 (APS>0), it can be seen that there is a willingness to accelerate.

In addition, in step b), the first time constant T1_Temp value may be output from a time constant map using a current gear ratio and an engine speed as factors.

In addition, an embodiment of the present invention,

e) If the accelerator pedal opening degree change rate α is less than or equal to the determination reference value, calculating a filtered final target torque by operating a torque filtering logic using the first time constant T1_Temp as a filter time constant; may further include .

Preferably, the determination reference value may be 40%/s.

In addition, the first time constant T1_Temp may be a number greater than or equal to 0 and less than 1.

In addition, the correction process preferably includes the steps of: d-1) outputting a correction coefficient k_Temp using a correction coefficient map using the accelerator pedal opening degree (APS) and the accelerator pedal opening degree change rate (α) as factors, and d-2) the Step b) multiplying the first time constant T1_Temp output in step by the correction factor k_Temp to obtain the first correction time constant T1_APS to be used only in the region above the determination reference value, and d-3) filter the obtained first correction time constant T1_APS It may include the step of calculating the filtered final target torque by operating the torque filtering logic used as.

In addition, the correction process includes: d-4) While the accelerator pedal opening degree change rate (α) is maintained in a state that exceeds the determination reference value, the correction coefficient k_Temp is output every predetermined time using the correction coefficient map, and the correction output every hour Calculating the accumulated correction coefficient k_Sum by accumulating the coefficient k_Temp and calculating the accumulated number n of the correction coefficient k_Temp, and d-5) calculating the average correction coefficient k_Avrg when the accelerator pedal opening change rate (α) becomes less than the judgment reference And d-6) multiplying the first time constant T1_Temp output in step b) by the average correction factor k_Avrg to obtain a second correction time constant T1_Cor to be used in a region less than the determination reference value; and d-7) It may further include the step of calculating the filtered final target torque by operating a torque filtering logic using the second correction time constant T1_Cor as a filter time constant.

Here, the correction factor k_Temp may be greater than 0 and less than or equal to 1.

Further, in step d-5), the moment when the accelerator pedal opening degree change rate α becomes less than or equal to the determination reference value, the average correction coefficient k_Avrg may be calculated by dividing the accumulated correction coefficient k_Sum up to that moment by the accumulation number n. .

According to an embodiment of the present invention, a process is configured so that the correction factor k can be continuously reflected even after the accelerator pedal opening degree is stabilized. Accordingly, there is an advantage that the driver's willingness to accelerate and accelerate can be reflected over the entire driving area. In other words, it has the advantage of reflecting the driver's willingness to accelerate according to various starting situations such as LTI, MTI, and FTI.

1 is a schematic diagram for explaining a torque filtering concept according to the prior art.
2 is a control flow chart for explaining a torque control method according to an embodiment of the present invention.
3 is an exemplary diagram of a correction coefficient map applied to the present invention.
Figure 4 is a schematic diagram comparing the conventional method and the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

In describing the present invention, terms used in the following specification are only used to describe specific embodiments, and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise.

In addition, in the present specification, terms such as "comprise" or "have" are intended to designate the presence of features, numbers, steps, actions, components, parts, or a combination thereof described in the specification, but one or more other It is to be understood that the presence or addition of features, numbers, steps, actions, components, parts, or combinations thereof, does not preclude in advance the possibility of being excluded.

In describing the present invention, when it is determined that a detailed description of related known technologies may unnecessarily obscure the subject matter of the present invention, a detailed description thereof will be omitted.

2 is a control flowchart illustrating a torque control method according to an embodiment of the present invention.

Referring to FIG. 2, the torque control method according to an embodiment of the present invention starts from the step S100 of checking the driver's willingness to accelerate. In step S100, preferably, if the gear is located in the D (Drive) stage and the accelerator pedal opening (%) is greater than 0, it can be seen that there is a willingness to accelerate. That is, if the gear is set to D and APS>0, it is determined that there is willingness to accelerate.

When the driver's willingness to accelerate is confirmed through the step S100, the next step is the first time constant to be used in calculating the final target torque after filtering the driver's required torque determined by the accelerator pedal operation through a low-pass filter. The step of outputting the T1_Temp value proceeds. That is, a step S200 of outputting a value of the first time constant T1_Temp for filtering the first requested torque proceeds.

In step S200, the first time constant T1_Temp value may be output from a time constant map using the current gear ratio and engine rotational speed as factors, and the first time constant T1_Temp stored in the time constant map is greater than or equal to 0 and less than 1. It can be a number. At this time, the closer the first time constant T1_Temp is to 0, the better the followability for the driver's torque demand is improved, and the start delay is suppressed.

When the first time constant T1_Temp corresponding to the current driving state of the vehicle is output from the time constant map using the current gear ratio and engine speed as factors, it is determined whether the accelerator pedal opening rate change rate α exceeds the judgment reference value. (S300). Here, the accelerator pedal opening degree change rate α means the change in the accelerator pedal opening degree (%) per unit time (s), and thus the unit may be expressed as %/s.

The determination reference value may preferably be 40%/s. That is, the point at which the accelerator pedal opening degree change per unit time (s) is 40% can be used as a judgment reference value. Of course, the judgment reference value is not limited to 40%/s. This is because there may be cases in which the driver's willingness to accelerate is reflected more than the driver's surge and shock during sudden acceleration, or the driver's surge and shock may be considered larger.

As a result of the determination through step S300, the process proceeds with two different routes depending on whether the accelerator pedal opening degree change rate α exceeds the determination reference value. The two processes are preferably a process for correcting the time constant by operating a correction process when the accelerator pedal opening degree change rate α exceeds the judgment reference value (S400), and the accelerator pedal opening degree change rate α is performed when the judgment reference value or less. It can be divided into a process (S500).

In step S500, it is determined that the driver's accelerator pedal input is relatively stable, and the first time constant T1_Temp output in step S200 is used as the filter time constant to operate the filter. That is, the torque filtering logic that applies the first time constant T1_Temp as the filter time constant is operated to filter the driver's requested torque with the low pass filter to calculate the final target torque in the α ≤ 40%/s range.

On the other hand, in step S400, which is performed when the accelerator pedal opening degree change rate α exceeds the determination reference value, a separate correction process is operated to correct the first time constant T1_Temp value output in step S200, and then filter the value after correction. The final target torque is calculated by filtering the driver's required torque with a time constant. The process of correcting the first time constant T1_Temp will be described in more detail.

When entering step S400, first, a correction coefficient k_Temp to be multiplied by the first time constant T1_Temp is output (S410). Here, the correction coefficient k_Temp may be output from a correction coefficient map using the accelerator pedal opening degree APS and the accelerator pedal opening degree change rate α as factors. That is, when the current accelerator pedal opening degree APS and the accelerator pedal opening degree change rate α are input, the corresponding correction coefficient k_Temp is determined and output from the correction coefficient map.

3 is a diagram illustrating a correction coefficient map, and the correction coefficient map is a map in which the correction coefficient for each opening degree and opening degree change rate section is converted into a table using the accelerator pedal opening degree (APS) and the accelerator pedal opening degree change rate (α) as factors. In addition, the correction coefficient k_Temp stored in the correction coefficient map may be greater than 0 and less than or equal to 1. That is, k_Temp may be 0 <k_Temp ≤ 1.

Here, k_Temp is a correction coefficient to be multiplied by the first time constant T1_Temp, as mentioned above, and the closer the correction coefficient k_Temp is to 0, the smaller the value of the time constant T1 after correction. That the time constant T1 becomes smaller means that the response of the first-order low-pass filter is improved, and when the response of the filter is improved, the followability to the driver's required torque is improved, thereby improving the oscillation feeling.

With continued reference to FIG. 2, when the correction coefficient k_Temp is output, the first time constant T1_Temp is corrected using the output correction coefficient k_Temp, so that the first correction to be used only in the region exceeding the judgment reference value (a region of α>40). The time constant T1_APS is obtained (S420). Here, the first correction time constant T1_APS may be a value obtained by multiplying the aforementioned first time constant T1_Temp by the correction factor k_Temp (T1_APS=T1_Temp*k_Temp).

When the first correction time constant T1_APS is obtained in step S420, a torque filtering logic using the obtained first correction time constant T1_APS as the filter time constant is operated to calculate the filtered final target torque (S430). Preferably, the first correction time constant T1_APS is applied as the filter time constant, and the torque required by the driver is filtered with a low pass filter, thereby calculating a final target torque in the range α>40%/s.

For reference, the first correction time constant T1_APS is a correction time constant applied only while the accelerator pedal opening degree change rate α is maintained in a state exceeding the determination reference value, as mentioned above. In other words, it is a correction time constant used only in the region α> 40%/s.

Subsequently, the correction coefficient k_Temp output in step S410 is accumulated every predetermined time, and the accumulated number n is calculated (S440). More specifically, while α> 40%/s is maintained, the correction coefficient k_Temp is outputted every predetermined time using the correction coefficient map, and the accumulated correction coefficient k_Sum is calculated and corrected by accumulating the correction coefficient k_Temp output every hour. Calculate the cumulative number n of the coefficient k_Temp.

Here, every predetermined time for outputting the correction coefficient k_Temp may be preferably 10 ms.

The above-described steps S410 to S440 are repeated while the accelerator pedal opening degree change rate α is maintained in a state that exceeds the above-described determination reference value (α> 40%/s). In other words, it repeats until the accelerator pedal opening change rate (α) is less than the judgment reference value (α ≤ 40%/s), and the time when the accelerator pedal opening change rate (α) becomes less than the judgment reference value (at α ≤ 40%/s) The average correction coefficient k_Avrg is calculated (S450).

Specifically, in step S450, the moment when the accelerator pedal opening degree change rate α becomes less than the judgment reference value, that is, when α ≤ 40%/s, the cumulative correction factor k_Sum up to that instant is divided by the cumulative number of times n, and the average correction is performed. The coefficient k_Avrg is output. For example, if the state of α> 40 lasted for 50ms and k_Temp = 0.2, 0.2, 0.4, 0.4, 0.4, measured 5 times, k_Avrg becomes (0.2 + 0.2 + 0.4 + 0.4 + 0.4) / 5 = 0.32. .

Next, the first time constant T1_Temp output in step S200 is multiplied by the average correction factor k_Avrg to obtain the second correction time constant T1_Cor to be used in the region below the determination reference value (a region of α ≤ 40%/s) (S460), and the obtained The torque filtering logic using the secondary correction time constant T1_Cor as the filter time constant is operated to calculate the final target torque when the accelerator pedal change rate α exceeds the determination reference value and falls below the determination reference value (S470).

In other words, in step S470, the torque filtering logic that applies the second correction time constant T1_Cor as the filter time constant is operated to filter the driver's requested torque with a low pass filter, so that α> 40%/s is maintained and then α ≤ 40%/s. It is to calculate the final target torque when it falls below the area.

4 is a schematic diagram comparing a conventional method and the present invention.

As shown in FIG. 4, the conventional time constant T1 does not reflect the correction factor k after the accelerator pedal opening degree is stabilized. This is because the correction factor k is applied only while a change in the accelerator pedal opening is detected. On the other hand, the present invention has the advantage that the correction factor k is continuously reflected even after the accelerator pedal opening is stabilized, so that the will of the driver to accelerate and accelerate can be reflected over the entire driving range.

In the above detailed description of the present invention, only specific embodiments according thereto have been described. However, it should be understood that the present invention is not limited to a particular form mentioned in the detailed description, but rather, it is understood to include all modifications, equivalents, and substitutes within the spirit and scope of the present invention as defined by the appended claims. Should be.

Claims (10)

a) checking whether the driver is willing to accelerate;
b) if the driver's willingness to accelerate is confirmed, outputting a first time constant T1_Temp for filtering the driver requested torque;
c) determining whether the accelerator pedal opening degree change rate α exceeds the determination reference value; And
d) If the accelerator pedal opening degree change rate (α) exceeds the judgment reference value, the correction process is started to correct the first time constant T1_Temp value, and the final target torque is calculated by filtering the driver's torque required by the filter time constant after the correction. Torque control method comprising a;
The method of claim 1,
In step a),
A torque control method that confirms that there is a willingness to accelerate when the gear is located in the D (Drive) stage and the accelerator pedal opening (APS) is greater than 0 (APS>0).
The method of claim 1,
The first time constant T1_Temp value in step b) is,
Torque control method output from the time constant map using the current gear ratio and engine speed as factors.
The method of claim 1,
e) If the accelerator pedal opening degree change rate α is less than or equal to the determination reference value, calculating a filtered final target torque by operating a torque filtering logic using the first time constant T1_Temp as a filter time constant; torque control further comprising: Way.
The method of claim 1,
The determination reference value is 40% / s torque control method.
The method of claim 1,
The first time constant T1_Temp is a number greater than or equal to 0 and less than 1. Torque control method.
The method of claim 1,
The correction process,
d-1) outputting a correction coefficient k_Temp using a correction coefficient map using the accelerator pedal opening degree (APS) and the accelerator pedal opening degree change rate (α) as factors;
d-2) multiplying the first time constant T1_Temp output in step b) by the correction factor k_Temp to obtain a first correction time constant T1_APS to be used only in an area greater than or equal to the determination reference value; And
d-3) calculating a filtered final target torque by operating a torque filtering logic using the obtained first correction time constant T1_APS as a filter time constant.
The method of claim 7,
d-4) While the accelerator pedal opening degree change rate (α) is maintained in a state that exceeds the judgment reference value, the correction coefficient k_Temp is output every predetermined time using the correction coefficient map, and the correction coefficient k_Temp output every hour is accumulated and accumulated. Calculating a correction coefficient k_Sum and calculating an accumulation number n of the correction coefficient k_Temp;
d-5) calculating an average correction coefficient k_Avrg when the accelerator pedal opening degree change rate α becomes equal to or less than the determination reference value;
d-6) multiplying the first time constant T1_Temp output in step b) by the average correction factor k_Avrg to obtain a second correction time constant T1_Cor to be used in a region below the determination reference value;
d-7) calculating a filtered final target torque by operating a torque filtering logic using the second correction time constant T1_Cor as a filter time constant.
The method of claim 8,
In step d-5),
A torque control method for calculating the average correction coefficient k_Avrg by dividing the cumulative correction factor k_Sum up to that moment by the cumulative number n at the moment when the accelerator pedal opening degree change rate α becomes less than or equal to the determination reference value.
The method of claim 7,
The correction factor k_Temp is greater than 0 and less than or equal to 1 torque control method.

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