KR102270683B1 - Engine ignition timing efficiency determination method - Google Patents

Abstract

The present invention relates to a method of determining an ignition timing efficiency curve, which is executed in a computer system. The method includes the following steps of: inputting n torque data sets by driving area in accordance with an ignition timing change of an engine; allocating an inclination factor, which can change an inclination of a curve indicated by each of the data sets by driving area, and a moving factor, which can move the curve parallelly, to each of the data sets by driving area; setting a logistic function having four freedom degrees, and an optimization function including a difference between the data sets to which the inclination factor and the moving factor have been allocated; and determining the logistic function, which is specified by the determination of the four freedom degrees, as an ignition timing efficiency curve of the engine by processing the optimization function through machine-learning. Therefore, the present invention is capable of more properly determining an ignition timing efficiency curve indicating the influence of engine torque.

Description

The method of determining the efficiency curve of the ignition timing of the engine {ENGINE IGNITION TIMING EFFICIENCY DETERMINATION METHOD}

The present invention relates to an ignition timing of an engine, which is an internal combustion engine, and an output torque of the engine accordingly.

What is the output torque of the engine is essential information for controlling various devices mounted in the vehicle, such as a transmission and a driving safety device, but since it is difficult to directly measure the engine torque through a sensor, an estimate based on a model is used.

In the case of a gasoline engine, even if other operating conditions are the same, if the ignition timing is changed, the engine torque is greatly changed. Therefore, the engine torque should be estimated by properly considering the ignition timing of the engine.

The matters described as the background technology of the invention are only for enhancing the understanding of the background of the present invention, and should not be taken as acknowledging that they correspond to the prior art already known to those of ordinary skill in the art. will be

KR 1020180064307 A

In order to enable a more accurate estimation of engine torque under various operating conditions of the engine, the present invention allows an ignition timing efficiency curve representing the effect of engine torque according to a change in the ignition timing of the engine to be more appropriately determined, and by using this An object of the present invention is to provide a method for determining an ignition timing efficiency curve of an engine, which enables the torque of an engine to be more accurately estimated.

The method of determining the ignition timing efficiency curve of the engine of the present invention for achieving the object as described above,

A method for determining an ignition timing efficiency curve of an engine performed in a computer system, the method comprising:

inputting torque data sets for n operation areas according to changes in ignition timing of the engine;

dividing the torque for the ignition timing at each operation point constituting the respective operation region by the maximum torque in the corresponding operation region, and normalizing it by moving in parallel so that the ignition timing at which the maximum torque is obtained becomes 0;

allocating a slope factor capable of changing the slope of a curve indicated by the torque data set for each operation area and a movement factor capable of moving the curve in parallel to the data set for each operation area;

setting a logistic function having four degrees of freedom and an optimization function including a difference between each data set to which the gradient factor and the movement factor are allocated;

processing the optimization function through machine learning to determine the logistic function specified by determining the four degrees of freedom as an ignition timing efficiency curve of the engine;

It is characterized in that it comprises a.

The operating region of the engine is basically determined by the engine speed and the load, and further determined by at least one of an exhaust valve opening angle, an intake valve closing angle, a valve opening duration, a valve lift, and an air ratio. .

The slope factor may be multiplied by the data set for each driving area, and the movement factor may be allocated in such a way that it is added to the data set for each driving area.

The logistic function is

Here, the four degrees of freedom are expressed as _{y 1} , y ₂ , y ₃ , y _{4 ,}

y ₁ , y ₂ , y ₄ > 0

can be

The optimization function is

=

here,

=

: 로지스틱함수의 4개의 자유도를 나타내는 변수

: Variable representing the four degrees of freedom of the logistic function

: 기울기펙터

: slope factor

: n개의 데이터 세트 중 i번째 데이터 세트

: the ith data set among n data sets

: 이동펙터

: movement factor

can be

The present invention comprises the steps of: storing the determined efficiency curve of the ignition timing of the engine in a storage medium;

It may be configured to further include.

In addition, the torque calculation method of the engine of the present invention for achieving the above object,

calculating the ignition efficiency for the current ignition timing from the ignition timing efficiency curve of the engine determined in the above manner;

calculating the torque of the engine by multiplying the maximum torque of the current operating region of the engine by the ignition efficiency;

It is characterized in that it comprises a.

The present invention makes it possible to more appropriately determine an ignition timing efficiency curve representing the effect of engine torque according to a change in ignition timing of an engine in order to enable more accurate estimation of engine torque under various operating conditions of the engine.

As described above, the more accurately estimated engine torque is applied to shift control of a vehicle transmission or control of a driving safety device to enable more accurate vehicle control, thereby ultimately improving shifting feeling, riding comfort, and safety of the vehicle.

1 is a flowchart showing an embodiment of a method for determining an ignition timing efficiency curve of an engine according to the present invention;
2 is a graph illustrating a result of measuring a change in torque according to a change in ignition timing while changing an engine load;
3 and 4 are graphs showing a change in torque according to a change in ignition timing of an engine in different operation regions, respectively;
5 is a graph in which the torque for the ignition timing at each operating point of the engine is divided by the MBT torque, and the MBT is moved in parallel so that it becomes 0;
6 is a graph expressing one ignition timing efficiency curve by converting curves formed by operating points belonging to each operating region of the engine in the same state as FIG. 5;
7 is a graph showing a basic logistic function used in the present invention;
8 is a diagram illustrating an engine controller for calculating engine torque using an ignition timing efficiency curve according to the present invention.

Referring to FIG. 1 , an embodiment of the method for determining an ignition timing efficiency curve of an engine according to the present invention is a method for determining an ignition timing efficiency curve of an engine performed in a computer system, and torque data for each n operation regions according to a change in the ignition timing of the engine inputting sets (S10); Normalizing by dividing the torque for the ignition timing at each operating point constituting the respective driving region by the maximum torque in the corresponding driving region, and moving in parallel so that the MBT becomes 0 (S20); allocating a slope factor capable of changing the slope of the curve indicated by the torque data set for each operation area and a movement factor capable of moving the curve in parallel to the data set for each operation area (S30); setting a logistic function having four degrees of freedom and an optimization function including a difference between each data set to which the gradient factor and the movement factor are allocated (S40); and processing the optimization function by machine learning to determine the logistic function specified by determining the four degrees of freedom as an ignition timing efficiency curve of the engine (S50).

The operating range of the engine is basically determined by the engine speed and the load, and further by at least one of an exhaust valve opening angle, an intake valve closing angle, a valve opening duration, a valve lift, and an air ratio (λ). It may be a determined area.

That is, the driving range of the engine refers to various individual driving situations that the engine mounted on the vehicle may face, and can be basically determined by the engine speed and the load, and the load is the accelerator pedal depression amount or It can be expressed as a throttle valve opening degree or the like.

The exhaust valve opening angle and intake valve closing angle are significant factors in an engine equipped with a variable valve timing device, and have a significant effect on the amount of residual inert gas in the combustion chamber due to internal EGR (Exhaust Gas Recirculation), which is the engine's Since it affects the combustion action and also affects the optimum ignition timing and ignition efficiency of the engine, it is desirable to consider them together.

The valve opening duration is the valve opening period according to the control of opening and closing timings of intake and exhaust valves in an engine to which CVVD (Continuously Variable Valve Duration) technology is applied, and the valve lift is intake in an engine to which CVVL (Continuously Variable Valve Lift) technology is applied. As the lift (head) of the valve and exhaust valve, these are factors that significantly affect the combustion action of the engine in the engine to which each technology is applied, so it can be considered together.

The air ratio is the ratio of the actual amount of air to the theoretical amount of air introduced into the combustion chamber, and it is desirable to consider this together because it also affects the combustion action of the engine and affects the optimum ignition timing and ignition efficiency of the engine.

Accordingly, preferably, the ignition timing for each operating region of the engine specified by the engine speed, load, exhaust valve opening angle, intake valve closing angle, valve opening duration, valve lift and air ratio is from the most delayed state to the most advanced state. It is preferable to obtain the torque data set for each operation area by measuring the engine torque at that time while changing it step by step.

Of course, since the number of operation areas determined by the seven factors is very large, it is preferable to conduct an experiment at an appropriate level to represent the corresponding engine using the experimental design method.

2 is a graph showing the results of measuring the torque change according to the ignition timing change while the remaining factors are fixed and only the load is changed among the seven factors determining the operation area of the engine. The points of can be viewed as corresponding to the torque data set of one operating region.

If the change in engine torque is observed while changing the ignition timing as described above, as illustrated in FIG. 3 , as the ignition timing is advanced, the torque increases and an ignition timing in which the torque starts to become maximum can be obtained. This ignition timing is called MBT (Minimum spark advance for Best Torque), and the torque at this time is called MBT torque, which means the maximum torque that the engine can actually exert in this operation range.

This MBT can be checked mainly in the low-speed and low-load region of the engine, but in the high-speed and high-load region, the engine torque increases as the ignition timing is advanced, and the ignition timing can no longer be advanced due to knocking, etc. Therefore, since it is impossible to confirm the MBT, there are cases where the MBT can only be obtained by estimation, as illustrated by the dotted line in FIG. 4 .

In the present invention, the torque for the ignition timing at each operating point of the engine is divided by the maximum torque in the operating region including each of the operating points, and parallel movement is made so that the ignition timing at which the maximum torque is obtained becomes 0. By normalizing in a way that makes it possible to obtain a picture as shown in FIG. 5 .

That is, in the operation region where MBT can be checked, the maximum torque is the MBT torque, so the torque for the ignition timing at each operating point is divided by the MBT torque, and the MBT is moved in parallel so that the MBT becomes 0. In , the torque for the ignition timing at each operating point is divided by the maximum torque of the corresponding operation region, and the parallel movement is performed so that the ignition timing at which the maximum torque is obtained becomes zero.

Therefore, in the operation region where the MBT cannot be confirmed, the practically impossible MBT is excluded and only the feasible operating points are reflected in the ignition timing efficiency curve, which will be described later.

In the state shown in FIG. 5, if a curve representing each driving region (one curve is formed by connecting driving points belonging to each driving region) is multiplied by an arbitrary multiple and properly moved in parallel, the curves of all driving regions are shown in FIG. The same curve can be drawn, and one curve drawn in this way is called "Ignition timing efficiency curve".

In the present invention, as a result, the curves representing each operating region expressed as shown in FIG. 5 are expressed as the ignition timing efficiency curve, which is one curve representing them, as shown in FIG. 6 .

In the present invention, the slope factor is multiplied by the data set for each driving area, and the movement factor is assigned in such a way that it is added to the data set for each driving area. The slope factor is multiplied by the curve of each driving area. The loss corresponds to a multiple, and the movement factor corresponds to a value added to move the curves of the respective driving areas in parallel.

The logistic function is a basic logistic function as shown in FIG. 7 changed as follows,

Here, the four degrees of freedom are expressed as _{y 1} , y ₂ , y ₃ , y _{4 ,}

y ₁ , y ₂ , y ₄ > 0.

That is, the logistic function of the present invention adds the four variables as described above to the basic logistic function shown in FIG. 7 so that the shape can be changed by appropriately adjusting these four variables, and ultimately, the As described above, it is a function used when representing the input torque data sets for each of the n operation areas with one ignition timing efficiency curve.

The optimization function is

=

here,

=

n: Number of torque data sets per operating area

: 각각 상기 로지스틱함수의 4개의 자유도 y₁, y₂, y₃, y₄를 나타내는 변수

: Variables representing _{four degrees of freedom y 1} , y ₂ , y ₃ , y 4 of the logistic function, respectively

: 기울기펙터

: slope factor

: n개의 데이터 세트 중 i번째 데이터 세트

: the ith data set among n data sets

: 이동펙터이다.

: It is a movement factor.

That is, the optimization function is a logistic function representing a target ignition timing efficiency curve, and RMSE (Root Mean Square Error) of torque measurement data for each operation region to which the slope factor and the movement factor are applied, and this optimization function is minimized 2n+4 variables are obtained by the machine learning.

As the machine learning technique, a conventionally known technique such as a gradient-based optimization algorithm or a genetic algorithm is used.

When the optimization function is processed with the machine learning technique as described above to obtain the values of 2n+4 variables, 2n of them correspond to the slope factor and the movement factor that have been allocated to the torque data set for each of the n driving areas, respectively, and , and the remaining four correspond to variables representing four degrees of freedom of the logistic function.

As described above, when the variables representing the four degrees of freedom determined by the machine learning technique are specified, the ignition timing efficiency curve of the engine is expressed by the specified four variables and the logic stick function.

That is, as shown in FIG. 5 , when the optimization function is set for the torque data sets of each driving region normalized and processed by machine learning, one representing the curves drawn by the torque data sets of all driving regions is one The ignition timing efficiency curve of can be obtained as shown in FIG.

The ignition timing efficiency curve of the engine determined as described above can be stored and utilized in a storage medium, and the logistic function in which the four variables are specified is stored in the storage medium, and this storage medium can be used in a way that is mounted on the vehicle. will be.

The storage medium may be a memory semiconductor or a memory or register built in a control unit.

On the other hand, as described above, since the inclination factor determined for the torque data set for each driving region substantially corresponds to the MBT torque in the driving region, the inclination factors for each driving region are stored to configure the maximum torque map for each region. .

8 exemplifies the engine control device for calculating the torque of the engine in the vehicle by using the maximum torque map for each area and the ignition timing efficiency curve configured as described above, wherein the calculating unit 1 performs the operation of the storage medium 3 . It is expressed that the ignition efficiency for the current ignition timing is calculated from the ignition timing efficiency curve 3-1, and the torque of the engine is calculated by multiplying the calculated ignition efficiency by the maximum torque in the current operating region of the engine.

That is, the calculating unit 1 receives the engine rotation speed, load, exhaust valve opening angle, intake valve closing angle, and air ratio as inputs, and calculates the maximum torque corresponding to the operation area accordingly in the maximum torque map for each area (3-2) , the current ignition timing is input, the ignition efficiency is calculated from the ignition timing efficiency curve 3-1, and then the calculated ignition efficiency is multiplied by the maximum torque to finally calculate the engine torque.

Of course, the maximum torque map 3-2 for each area may also be stored in the storage medium 3 storing the ignition timing efficiency curve 3-1, and FIG. 8 illustrates such a case. have.

In the vehicle, the torque of the engine calculated as described above is applied to the shift control of the transmission or the control of the driving safety device to enable more accurate vehicle control, thereby ultimately improving the shifting feeling, riding comfort, and safety of the vehicle.

Although the present invention has been shown and described with reference to specific embodiments, it is within the art that the present invention can be variously improved and changed without departing from the spirit of the present invention provided by the following claims. It will be obvious to those of ordinary skill in the art.

One; arithmetic part
3; storage medium
3-1; Ignition Timing Efficiency Curve
3-2; Maximum torque map by area

Claims (9)

A method for determining an ignition timing efficiency curve of an engine performed in a computer system, the method comprising:
inputting torque data sets for n operation areas according to changes in ignition timing of the engine;
dividing the torque for the ignition timing at each operation point constituting the respective operation region by the maximum torque in the corresponding operation region, and normalizing it by moving in parallel so that the ignition timing at which the maximum torque is obtained becomes 0;
allocating a slope factor capable of changing the slope of a curve indicated by the torque data set for each operation area and a movement factor capable of moving the curve in parallel to the data set for each operation area;
setting a logistic function having four degrees of freedom and an optimization function including a difference between each data set to which the gradient factor and the movement factor are allocated;
processing the optimization function through machine learning to determine the logistic function specified by determining the four degrees of freedom as an ignition timing efficiency curve of the engine;
A method for determining an ignition timing efficiency curve of an engine, characterized in that it comprises a. The method according to claim 1,
The operating area of the engine is basically determined by the engine speed and the load, and further determined by at least one of an exhaust valve opening angle, an intake valve closing angle, a valve opening duration, a valve lift, and an air ratio.
A method for determining an ignition timing efficiency curve of an engine, characterized in that The method according to claim 1,
The slope factor is multiplied by the data set for each driving area, and the movement factor is assigned in such a way that it is added to the data set for each driving area.
A method for determining an ignition timing efficiency curve of an engine, characterized in that The method according to claim 1,
The logistic function is

Here, the four degrees of freedom are expressed as _{y 1} , y ₂ , y ₃ , y _{4 ,}
y ₁ , y ₂ , y ₄ > 0
Method for determining the efficiency curve of the ignition timing of the engine, characterized in that The method according to claim 1,
The optimization function is

here,

=

n: Number of torque data sets per operating area

: Variable representing the four degrees of freedom of the logistic function

: slope factor

: the ith data set among n data sets

: movement factor
Method for determining the efficiency curve of the ignition timing of the engine, characterized in that The method according to claim 1,
storing the determined ignition timing efficiency curve of the engine in a storage medium;
The method of determining the efficiency curve of the ignition timing of the engine, characterized in that it further comprises a. Calculating the ignition efficiency for the current ignition timing from the ignition timing efficiency curve of the engine determined by the method of any one of claims 1 to 6;
calculating the torque of the engine by multiplying the maximum torque of the current operating region of the engine by the ignition efficiency;
Torque calculation method of the engine, characterized in that configured to include. A storage medium storing the ignition timing efficiency curve of the engine determined by the method of any one of claims 1 to 6. A storage medium storing the ignition timing efficiency curve of the engine determined by the method of any one of claims 1 to 6;
a calculating unit for calculating the ignition efficiency for the current ignition timing from the ignition timing efficiency curve of the storage medium, and calculating the torque of the engine by multiplying the calculated ignition efficiency by the maximum torque of the current operating region of the engine;
An engine control device comprising a.

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