阅读说明：本技术 用于控制低压燃料泵的方法及用于该方法的燃料供应系统 (Method for controlling low-pressure fuel pump and fuel supply system for the method ) 是由 金龙植 于 2019-06-18 设计创作，主要内容包括：本发明涉及用于控制低压燃料泵的方法及用于该方法的燃料供应系统。控制低压燃料泵的方法可以包括：响应于前馈燃料控制,识别低压燃料泵的燃料消耗量；基于燃料消耗量确定电机驱动基本占空；以及基于燃料压力识别目标燃料压力。(The invention relates to a method for controlling a low-pressure fuel pump and a fuel supply system for the method. The method of controlling the low-pressure fuel pump may include: identifying a fuel consumption amount of a low-pressure fuel pump in response to the feed-forward fuel control; determining a motor drive base duty based on the fuel consumption amount; and identifying a target fuel pressure based on the fuel pressure.)

1. A method of controlling a low pressure fuel pump, the method comprising:

identifying a fuel consumption amount of a low-pressure fuel pump in response to the feed-forward fuel control;

determining a motor drive base duty based on the fuel consumption amount;

a target fuel pressure is identified based on the fuel pressure.

2. The method of claim 1, wherein identifying a fuel consumption amount and a target fuel pressure is performed through CAN communication.

3. The method of claim 1, wherein determining the motor drive base duty is performed by a feed forward controller, wherein identifying a fuel consumption amount set based on a flow signal of injected fuel received by the feed forward controller and then generating a value of the motor drive base duty.

4. The method of claim 1, wherein identifying a target fuel pressure is performed based on a fuel temperature model.

5. The method of claim 1, wherein identifying a fuel consumption of a low pressure fuel pump comprises:

measuring an actual pressure of the fuel;

determining a correction duty for correcting the motor drive based on the measured actual pressure of the fuel and the target fuel pressure of the fuel;

calculating a motor drive duty based on the correction amount;

determining a final drive duty based on the correction of the output;

the motor is driven based on the final drive duty.

6. The method of claim 5, wherein measuring the actual pressure of the fuel is performed by a pressure sensor.

7. A method according to claim 5 wherein the correction amount increases with or is proportional to the pressure difference as a positive correction amount when the pressure difference of target fuel pressure minus measured actual pressure of fuel is greater than 0 when determining a correction duty-off.

8. A method according to claim 5 wherein the correction amount increases as the pressure difference or is proportional to the pressure difference as a negative correction when the pressure difference of target fuel pressure minus measured actual pressure of fuel is less than 0 when determining a correction duty-off.

9. The method of claim 5, wherein the new value of the motor drive duty is calculated by adding the correction amount to the old value of the motor drive duty.

10. The method according to claim 5, wherein the final drive duty is calculated by adding a correction amount of the dead time to the motor drive duty,

the correction amount of the dead time compensates for a dead time during which the low-pressure fuel pump does not respond to the motor drive duty.

11. A fuel supply system, comprising:

an engine control unit;

a fuel pump controller configured to receive a target fuel pressure from the engine control unit;

a low-pressure fuel pump configured to pump out fuel at a low pressure based on a fuel consumption amount as a feedforward control variable;

a pressure sensor configured to detect a pumping pressure of the low-pressure fuel pump;

a high-pressure fuel pump configured to receive a fuel flow rate from the low-pressure fuel pump and pump out fuel at a high pressure;

an injector configured to receive fuel from the high-pressure fuel pump and to inject the fuel.

12. The fuel supply system of claim 11, wherein the fuel pump controller comprises:

a feed-forward controller configured to receive a flow signal of injected fuel from the engine control unit;

a proportional-integral controller configured to receive the target fuel pressure from the engine control unit;

a feed forward compensation device configured to determine a final drive duty of the motor and send a signal having a pulse width t to the low pressure fuel pump.

Technical Field

The present invention relates to a method of controlling a low-pressure fuel pump to reduce fuel consumption and a fuel supply system implementing the method.

Background

The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.

In a fuel supply system such as a gasoline direct injection engine that requires fuel to be injected into a combustion chamber at high pressure, compatibility between the optimum point of fuel efficiency and fuel supply stability is very important.

For example, in order to achieve an optimum point of fuel efficiency, it is necessary to minimize the fuel consumption amount to improve the fuel efficiency; in order to achieve stability of fuel supply, it is necessary to increase the amount of fuel supply to prevent engine lag and engine stall. Therefore, the optimum point of fuel efficiency and the stability of fuel supply are contradictory, so compatibility between the two is a technical difficulty.

This makes the fueling system indiscriminate and gives priority to fueling stability.

This is because the fuel supply system consists of a high-pressure fuel pump producing a fuel injection pressure of about 30 to 200 bar and a low-pressure fuel pump producing a fuel pumping pressure of about 3 to 6 bar, and the low-pressure line of the low-pressure fuel pump always risks the generation of cavitation or bubbles related to the saturation vapor pressure of the fuel.

Therefore, in order to ensure the stability of the fuel supply, the fuel supply system employs a control manner of raising the target pressure of the low-pressure fuel pump. The control manner of raising the target pressure helps to solve the cause of the following phenomena: the pressure drops below the saturation vapor pressure of the low-pressure line due to transient over-consumption of fuel; cavitation or air bubbles are generated due to insufficient correction of the fuel temperature to vary the saturated vapor pressure and due to non-reaction of the fuel properties based on the degree of volatilization and alcohol content of the fuel.

Accordingly, if the fuel supply system controls the low-pressure fuel pump in a controlled manner to raise the target pressure, the gasoline direct injection engine can be operated without causing engine lag and engine stall.

However, we have found that there is a problem in a control scheme of raising the target pressure of the low-pressure fuel pump in that fuel efficiency is deteriorated because a final mapping point having a higher margin than an ideal optimum point of the saturated vapor pressure (at which the fuel can be kept in a liquid state) is applied to a pressure-temperature saturated vapor pressure map of the fuel, fuel consumption is large.

Disclosure of Invention

The present invention provides a method of controlling a low-pressure fuel pump in a manner to reduce fuel consumption, thereby achieving better compatibility of improved fuel efficiency with fuel supply stability (which are generally contradictory) by taking fuel consumption as a control variable. Further, in a state where fuel consumption for obtaining an optimum point of fuel efficiency is minimized or significantly reduced, stability of fuel supply can be secured by suppressing or preventing generation of cavitation or bubbles.

Other objects and advantages of the present invention will be understood by the following description, and will become more apparent with reference to the embodiments of the present invention. Further, it will be apparent to those skilled in the art that the objects and advantages of the present invention can be realized by the means as claimed and combinations of the means as described.

According to one aspect of the present invention, a method of controlling a low pressure fuel pump to reduce or minimize fuel consumption includes: controlling a setting of a low-pressure fuel pump according to an operation of the engine in response to feed-forward control of a fuel consumption amount; controlling correction of a low-pressure fuel pump according to the pressure of the fuel; and controlling the supply of fuel injected from the injector.

Controlling the settings of the low-pressure fuel pump may include: identifying operation of the engine; identifying a fuel consumption, wherein the fuel consumption is taken as a feed forward control variable; determining a motor driving base duty for driving the motor; and identifying a target fuel pressure for achieving an optimum point of fuel efficiency and stability of fuel supply.

Identifying the fuel consumption amount and identifying the target fuel pressure may be performed by Controller Area Network (CAN) communication.

The determination of the motor drive basic duty may be performed by a feedforward controller, and the fuel consumption amount is set and determined in accordance with a flow rate signal of the injected fuel received by the feedforward controller, and then a value of the motor drive basic duty is generated.

Identifying the target fuel pressure may be performed based on a fuel temperature model.

Controlling the correction to the low pressure fuel pump may include: measuring an actual pressure of the fuel; determining a correction duty for correcting the motor drive; calculating a motor drive duty based on the correction amount; determining a final drive duty based on the correction of the output; and driving the motor based on the output correction.

Measuring the actual pressure of the fuel may be performed by a pressure sensor.

When the pressure difference of the target fuel pressure minus the measured actual pressure of the fuel is greater than 0 when determining the correction duty, the correction amount as a positive correction amount can be calculated by the following formula:

the correction amount D1 is the gain 1 × (target pressure — measured actual pressure).

When the pressure difference of the target fuel pressure minus the measured actual pressure of the fuel is less than 0 when determining the correction duty, the correction amount as a negative correction amount can be calculated by the following formula:

the correction amount D2 is gain 2 × (target pressure — measured actual pressure).

The motor drive duty is calculated by the following formula:

duty (n) ═ duty (n-1) + correction amount

The final drive duty is calculated by the following formula:

final duty (n) + dead time correction

According to another aspect of the present invention, a fuel supply system may include: an Engine Control Unit (ECU), a fuel pump controller, a low-pressure fuel pump, a pressure sensor, a high-pressure fuel pump, and an injector; the fuel pump controller receiving a target fuel pressure from an ECU; the low-pressure fuel pump is used for pumping out fuel at low pressure based on fuel consumption as a feedforward control variable; the pressure sensor is used for detecting the pumping pressure of the low-pressure fuel pump; the high-pressure fuel pump is configured to receive a flow of fuel from the low-pressure fuel pump and pump the fuel at a high pressure; the injector is configured to receive fuel from a high-pressure fuel pump and inject the fuel.

The fuel pump controller may include: a feedforward controller, a Proportional Integral (PI) controller, and a feedforward compensation device, the feedforward controller receiving a flow signal of injected fuel from an ECU; the Proportional Integral (PI) controller receiving a target fuel pressure from an ECU; the feed forward compensation means is used to determine the final drive duty of the motor and send a signal having a pulse width t to the low pressure fuel pump.

The method of variably controlling the low pressure fuel pump according to one embodiment of the present invention may control the fuel consumption amount to be reduced or minimized by using the fuel consumption amount as a control variable, thereby improving fuel efficiency and securing stability of fuel supply.

Further, according to the present invention, it is possible to secure the stability of fuel supply by solving the cause of cavitation or bubble generation in the state where the optimum point of fuel efficiency is secured by minimizing the amount of fuel consumption, thereby solving the contradiction between the optimum point of fuel efficiency and the stability of fuel supply, which is a problem in the conventional fuel supply system for a gasoline direct injection engine, while achieving compatibility between the optimum point of fuel efficiency and the stability of fuel supply.

It is to be understood that both the foregoing general description and the following detailed description of the present invention are exemplary and explanatory and are intended to provide further explanation of the invention as claimed.

Further areas of applicability will become apparent from the description provided herein. It should be understood that the description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.

Drawings

In order that the invention may be better understood, various embodiments of the invention will be described, by way of example, with reference to the accompanying drawings, in which:

fig. 1 is a flowchart illustrating a method for controlling a low-pressure fuel pump according to an embodiment of the present invention;

FIG. 2 is a schematic diagram of a fuel supply system in which a low-pressure fuel pump is variably controlled to reduce fuel consumption according to an embodiment of the present invention;

FIG. 3 is a schematic diagram showing the operation of the fuel supply system when the low pressure fuel pump is variably controlled to reduce fuel consumption;

FIG. 4 is a schematic diagram showing the relationship between pressure and volume with respect to the fuel consumption amount of a low-pressure fuel pump constituting the fuel supply system; and

fig. 5 is a schematic diagram of the saturation vapor pressure employed in determining the target fuel pressure of the fuel temperature model constituting the fuel supply system.

The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way.

Detailed Description

The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses. It should be understood that throughout the drawings, corresponding reference numerals indicate like or corresponding parts and features.

The exemplary embodiments described below are provided to enable those skilled in the art to easily understand the technical spirit of the present invention, and the present invention is not limited thereto. Furthermore, the matters shown in the accompanying drawings are illustrated for the purpose of describing exemplary embodiments of the present invention and may be configured differently from an actual implementation.

It will be understood that when an element is referred to as being coupled or connected to another element, it can be directly coupled or connected to the other element, but with the interposition of another element.

The term "connected" as used herein includes direct and indirect connections between one member and another member, and may mean all physical connections, such as adhesion, attachment, fastening, adhesion, and coupling.

Furthermore, descriptions such as "first," "second," etc. are used merely to distinguish between components and not to limit the order or other features of the components.

Unless the context clearly dictates otherwise, expressions in the singular also include expressions in the plural. The terms "comprises" or "comprising" are intended to mean that a feature, number, step, operation, component, element, or combination thereof described in this specification is included, and may be interpreted as adding one or more other features, numbers, steps, operations, components, elements, or combinations thereof.

Referring to fig. 1, a method of variably controlling a low pressure fuel pump in a manner of minimizing fuel consumption includes: in steps S10 to S40, the setting of the low-pressure fuel pump is controlled in accordance with the operation of the engine in response to feed-forward control of the fuel consumption amount; in steps S50 to S100, the correction to the low-pressure fuel pump is controlled in accordance with the pressure of the fuel; and in step S110, controlling supply of fuel injected from the injector.

Specifically, in steps S10 to S40 of controlling the setting of the low-pressure fuel pump, the fuel consumption amount is regarded as a feedforward control variable, so that the fuel consumption amount can be reduced or minimized to achieve the optimum point of fuel efficiency in a state where stability of fuel supply is provided without generating cavitation or bubbles. In this case, considering the fuel consumption amount as a control variable, it is possible to reduce the fuel consumption amount required for preventing engine lag and engine stall without increasing the fuel supply as in the conventional fuel supply stability. Further, the feed-forward control determines the motor drive basic duty of the fuel consumption amount before the calculation of the target fuel pressure, so that the fuel consumption can be more effectively reduced by regarding the fuel consumption amount as a control variable, unlike the feedback control in which the target fuel pressure is directly applied.

Therefore, the method of controlling the low-pressure fuel pump can control the fuel supply system to have compatibility between the optimum point of fuel efficiency and the stability of fuel supply without conflict between the optimum point of fuel efficiency and the stability of fuel supply, which is a problem in the prior art.

Referring to fig. 2, the fuel supply system includes: an Engine Control Unit (ECU) 110, a fuel pump controller 120, a low-pressure fuel pump 130, a pressure sensor 140, a high-pressure fuel pump 150, and an injector 160.

For example, the ECU110 provides a target fuel pressure (based on a fuel temperature model) and a fuel consumption amount, manages a fault code, and operates a warning lamp, wherein the ECU110 provides the target fuel pressure (relative pressure) to the fuel pump controller 120.

The fuel pump controller 120 performs driving of the pump in response to the fuel consumption amount, receives the fuel pressure feedback control and the actual pressure (absolute pressure) measured by the pressure sensor 140, and performs conversion of the measured actual pressure into a relative pressure, real-time failure diagnosis, and transmission of the result, wherein the fuel pump controller 120 transmits the current fuel pressure (relative pressure) and the failure diagnosis to the ECU 110.

The low-pressure fuel pump 130 is controlled by the fuel pump controller 120 and pumps out fuel (pumping pressure: 3.5 to 6.0 bar) in consideration of the fuel consumption amount as a feedforward control variable.

The pressure sensor 140 detects the pumping pressure of the low-pressure fuel pump 130 and sends the detected pressure to the fuel pump controller 120.

High-pressure fuel pump 150 receives the flow rate of fuel from low-pressure fuel pump 130 and then pumps out the fuel (pumping pressure: 30 to 200 bar).

Injector 160 injects the fuel pumped out from high-pressure fuel pump 150 into the combustion chamber of the engine.

A method for controlling a low pressure fuel pump to reduce fuel consumption according to an embodiment of the present invention is described in detail below with reference to fig. 3 to 5. In this case, the control subject is the fuel pump controller 120 associated with the ECU110, and the controlled object is the low-pressure fuel pump 130. Further, identifying the fuel consumption amount, identifying the target fuel pressure, and measuring the actual fuel pressure may be performed through Controller Area Network (CAN) communication. CAN communication is a standard communication protocol designed for mutual communication between microcontrollers or devices, without the need for a host in the vehicle.

Steps S10 to S40 of controlling the setting of the low-pressure fuel pump are performed by the fuel pump controller 120, in which step S10 of recognizing the operation of the engine, step S20 of recognizing the fuel consumption amount, step S30 of determining the motor drive basic duty, and step S40 of recognizing the target fuel pressure are performed.

Referring to fig. 3, the fuel pump controller 120 includes a feed forward controller 122, a Proportional Integral (PI) controller 124, and a feed forward compensation device 126 as components that execute control logic for variably controlling the low pressure fuel pump in a manner that minimizes fuel consumption, wherein the feed forward controller 122, the Proportional Integral (PI) controller 124, and the feed forward compensation device 126 are configured together by software and hardware.

Specifically, step S20 of recognizing the fuel consumption amount is executed by the feedforward controller 122 upon receiving a flow rate signal of the injected fuel from the ECU 110. The step S30 of determining the motor drive basic duty is performed by the feedforward controller 122, in which the fuel consumption amount set according to the flow rate signal of the injected fuel received by the feedforward controller is identified, and then the value of the motor drive basic duty of the low-pressure fuel pump 130 corresponding to the identified fuel consumption amount is generated. In this case, the value of the motor drive duty based on the fuel consumption amount is defined as the motor drive basic duty.

Referring to fig. 4, it is possible to improve fuel efficiency by controlling the discharge amount of the low pressure fuel pump based on the fuel consumption amount (fuel supply amount) to prevent the generation of the pressure difference according to the following formula.

dp/dt＝K/V·dV/dt＝K/V·(q_in-q_out)

Wherein p represents pressure, V represents volume, q represents_inDenotes pump discharge amount, q_outIndicating fuel consumption, and K represents a constant.

Specifically, information of the fuel consumption amount is sent from the ECU110 to the fuel pump controller 120 through CAN communication to control the discharge amount of the low-pressure fuel pump.

Further, a fuel temperature sensor or a fuel temperature model is applied to improve fuel efficiency while ensuring stability of fuel supply, so that a minimum pressure at which the fuel can be kept in a liquid state for each temperature of the fuel can be set. The fuel temperature model is the minimum pressure line at which the fuel can remain in a liquid state.

The fuel temperature model is applied to maintain the pressure of the low pressure line above the saturation vapor pressure so that the fuel can be maintained in a liquid state. The pressure of the low pressure line is the pressure of the conduit line, wherein the conduit line is maintained at a minimum pressure above the saturation vapor pressure to maintain the fuel in a liquid state.

Step S40 of identifying the target fuel pressure is performed by the PI controller 124, wherein the target fuel pressure is received from the ECU110, and a proportional (P) duty value and an integral (I) duty value of the target fuel pressure are generated.

Referring now to fig. 5, a graph showing how a margin is applied to prevent fuel from bubbling due to instantaneous fuel consumption is shown.

In this figure, the saturation vapor pressure curves for fuel a and fuel B (which are the same fuel but have different temperatures) are shown, where the saturation vapor pressure curves are known to represent the minimum pressure at which the gas remains in the liquid state. Where T on the x-axis represents absolute temperature and P on the y-axis represents pressure.

In the prior art, in order to prevent the generation of fuel bubbles, a final mapping point (having an upward margin higher than an ideal optimum point of a liquid fuel) is applied when controlling the fuel, thereby preventing the fuel from becoming a gaseous state and remaining in a liquid state through instantaneous fuel consumption. Therefore, there is a problem that fuel efficiency is deteriorated due to a large fuel consumption amount.

However, the method of variably controlling the low pressure fuel pump according to the present invention may control the fuel consumption amount to be minimized by using the fuel consumption amount as a control variable, thereby improving fuel efficiency and securing stability of fuel supply.

Here, it is to be noted that the motor driving basic duty refers to a duty for driving a basic motor, and the fuel temperature model is conceived to minimize fuel consumption according to the fuel consumption amount of the pressure line for keeping the fuel in a liquid state.

The fuel consumption amount and the target fuel pressure are identified using the final map point, the ideal map point, and the target pressure margin. Here, it should be noted that the final mapping point is a pressure correction value for preventing the fuel from changing from the liquid state to the gas state, the ideal mapping point is the lowest pressure at which the fuel can be kept in the liquid state, and the target pressure margin is a pressure deviation within which the fuel can be prevented from changing from the liquid state to the gas state.

Specifically, the feedforward compensation means 126 receives the sum of the duty value of the fuel consumption amount and the PI duty value of the target fuel pressure, applies the compensation value to determine the final drive duty, and then outputs a signal having the pulse width t to the low-pressure fuel pump 130.

Subsequently, steps S50 to S100 of controlling the correction to the low-pressure fuel pump are performed by the fuel pump controller 120, in which step S50 of measuring the actual fuel pressure is performed; a step S60 of determining a correction duty; a step S70 of determining a correction duty when a pressure difference of the target fuel pressure minus the measured actual pressure is greater than 0; a step S61 of determining a correction duty when a pressure difference of the target fuel pressure minus the measured actual pressure is less than 0; step S80 of calculating the motor drive duty, step S90 of calculating the final drive duty, and step S100 of driving the motor.

Specifically, in step S50, where the actual fuel pressure is measured, the actual fuel pressure of the low-pressure fuel pump is measured by the pressure sensor 140 after the target fuel pressure is recognized by the fuel pump controller 120. The measured actual pressure of the fuel obtained by measuring the actual pressure of the fuel refers to a measured fuel pressure with respect to atmospheric pressure (absolute pressure), and is also referred to as a measured actual pressure. The fuel pump controller 120 converts the measured actual pressure of the fuel into a relative pressure, then sends the converted pressure to the ECU110 and performs a failure diagnosis using the converted pressure.

Next, in step S60 of determining a correction duty, which is determined using a pressure difference of the target fuel pressure minus the measured actual pressure of the fuel, a drive duty for driving the motor is calculated. Here, the correction duty is a correction duty for driving the motor, in which correction coefficients other than the correction coefficient for the motor are excluded. If the pressure difference of the target fuel pressure minus the measured actual pressure of the fuel is greater than 0, in step S70 of determining the correction duty, the correction duty is obtained by the following formula.

Correction amount D1 (or positive correction amount) gain 1 × (target pressure-measured actual pressure)

Wherein the gain 1 represents a first correction constant.

In contrast, if the pressure difference of the target fuel pressure minus the measured actual pressure of the fuel is less than 0, in step S61 of determining the correction duty, the correction duty is obtained by the following formula.

Correction amount D2 (or negative correction amount) gain 2 × (target pressure-measured actual pressure)

Wherein the gain 2 represents the second correction amount.

Therefore, each of the correction amount D1 as a positive correction amount and the correction amount D2 as a negative correction amount has the feature that: increases with or is proportional to the difference in the target fuel pressure minus the measured actual pressure of the fuel, respectively. In step S80 of calculating the motor drive duty, the motor drive duty is obtained using the obtained correction amount, wherein the motor drive duty is obtained by the following equation.

Duty (n) ═ duty (n-1) + correction amount

Thus, a new value of the motor drive duty is calculated by adding the correction amount D1, which is a positive correction amount, or the correction amount D2, which is a negative correction amount, to the old value (i.e., the previous value) of the motor drive duty. Subsequently, in step S90 of determining the final drive duty, the final drive duty for driving the motor is determined, and in step S100 of driving the motor, the motor is driven accordingly. The final drive duty is obtained by the following formula.

Final duty (n) + dead time correction

Thus, the final motor drive duty is calculated by adding the correction amount of the dead time to the new value of the motor drive duty. Where dead time represents the time elapsed from the time of the input change to the time the output change is detected. Therefore, the elapsed time of the dead time may offset the dead zone in which the low-pressure fuel pump 130 does not actually respond to the input of the motor drive duty. The correction amount of the dead time represents a correction amount of an elapsed time from the time of the input change to the time of the detection of the output change. Such correction of the dead time makes it possible to perform precise control without delay. Therefore, the correction amount of the dead time that compensates for the dead time enables the low-pressure fuel pump 130 to quickly respond to the input of the final drive duty.

Then, the fuel pump controller 120 executes step S110 of controlling fuel supply. In step S110 of controlling fuel supply, fuel supply is performed in the following manner: low-pressure fuel pump 130 pumps fuel at a low pressure to high-pressure fuel pump 150, and high-pressure fuel pump 150 pumps fuel at a high pressure, and then injects fuel from injector 160.

It will be appreciated by those skilled in the art that the present invention may be embodied in other specific embodiments without departing from the spirit or essential characteristics thereof. Therefore, it should be understood that the above-described embodiments are selected from various possible examples only for the purpose of making those skilled in the art understand the present invention, and thus the technical spirit of the present invention is not necessarily limited or limited only by the provided embodiments, and various changes, additions and modifications may be made without departing from the spirit of the present invention, and other embodiments equivalent to the present invention are also possible. The scope of the present invention is defined by the appended claims, not the above description, and all changes or modifications derived from the meaning and scope of the claims and equivalents thereof should be construed as being included in the scope of the present invention. The terms and words used in the specification and claims are defined based on the following principles: in order to describe his/her own invention in the best way, the inventor can properly define the concept of terms and should not be interpreted as only the ordinary meaning of these terms or the meaning in dictionaries. Further, the order of the configurations described in the foregoing description need not be executed in time-series order, naturally, and although the order of executing each configuration or step is changed, it would be within the scope of the present invention if such a change is in conformity with the gist of the present invention.