阅读说明：本技术 一种计算主动净化系统中的空气量的方法 (Method for calculating air quantity in active purification system ) 是由 吴永圭 朴金真 于 2020-07-29 设计创作，主要内容包括：一种确定主动净化净化系统中空气量的方法可以包括：检查发动机是否运行在怠速状态下；响应于从设置在进气管中的传感器接收的信号,确定到达发动机的燃烧室的空气量；检查收集在罐中的蒸发气体是否被引入进气管；估计被引入进气管的蒸发气体的量,并且对根据蒸发气体的估计量所确定的空气量进行初次校正；检查发动机中进气门的打开保持时间是否由于电连接至控制器的连续可变气门持续时间系统的操作而改变；并且通过将连续可变气门持续时间系统的操作负荷代入预先设置的公式、表格或映射图中而得到校正变量,并且根据校正变量对初次校正的空气量进行二次校正。(A method of determining an amount of air in an active purification system can include: checking whether the engine is operated in an idle state; determining an amount of air reaching a combustion chamber of the engine in response to a signal received from a sensor provided in an intake pipe; checking whether the boil-off gas collected in the canister is introduced into the intake pipe; estimating an amount of the boil-off gas introduced into the intake pipe, and primarily correcting an air amount determined in accordance with the estimated amount of the boil-off gas; checking whether an open holding time of an intake valve in the engine is changed due to an operation of a continuous variable valve duration system electrically connected to a controller; and a correction variable is obtained by substituting the operation load of the continuous variable valve duration system into a preset formula, table, or map, and the primarily corrected air amount is secondarily corrected according to the correction variable.)

1. A method of determining the amount of air in a purification system, the method comprising:

checking, by a controller, whether an engine is operating in an idle state;

determining, by the controller, an amount of air reaching a combustion chamber of the engine in response to a signal received from a sensor installed in an intake pipe when the engine is operating in an idle state;

checking, by the controller, whether the evaporation gas collected in the canister is introduced into the intake pipe when the engine is operating in an idle state;

estimating, by the controller, an amount of the boil-off gas introduced into the intake pipe when it is determined that the boil-off gas is introduced into the intake pipe, and primarily correcting an air amount determined in accordance with the estimated amount of the boil-off gas;

checking, by the controller, whether an open hold time of an intake valve in the engine changes due to operation of a continuously variable valve duration system electrically connected to the controller; and

when the open holding time of an intake valve in the engine is changed due to the operation of a continuous variable valve duration system, a correction variable is obtained by the controller based on the operation load of the continuous variable valve duration system, and the primarily corrected air amount is secondarily corrected in accordance with the correction variable.

2. The method of claim 1, wherein the first and second light sources are selected from the group consisting of,

wherein, in checking whether the engine is operating in the idle state, the controller is configured to check whether a temperature of a coolant of the engine is higher than or equal to a predetermined value, and

wherein the controller interrupts an evaporated gas purge process of the purge system or an operation of the continuously variable valve duration system when it is determined that the engine is not in the idle state or the temperature of the coolant is lower than the predetermined value.

3. The method of claim 1, wherein the sensor comprises:

a hot film air mass flow sensor located between the air filter and the throttle; and

a manifold absolute pressure sensor located between the throttle valve and the combustion chamber.

4. The method of claim 1, wherein the first and second light sources are selected from the group consisting of,

wherein the canister is connected to the intake pipe by a purge line;

wherein, a purification control valve is arranged on the purification pipeline;

wherein a purge pump is installed on a purge line between the purge control valve and the canister;

wherein a first pressure sensor is mounted on a purge line between the tank and the purge pump;

a second pressure sensor is arranged on a purification pipeline between the purification pump and the purification control valve; and is

Wherein the controller is configured to estimate the amount of the evaporation gas according to an operation load of the purge pump.

5. The method according to claim 4, wherein the controller is configured to estimate the amount of the evaporation gas based on a number of revolutions per minute of the purge pump, opening and closing timings of the purge control valve, an opening amount of the purge control valve, a signal generated from the first pressure sensor, and a signal generated from the second pressure sensor.

6. The method of claim 1, wherein deriving, by the controller, the correcting variable based on an operating load of the continuously variable valve duration system comprises: the correcting variable is obtained by the controller by substituting the operation load of the continuously variable valve duration system into a predetermined formula, a predetermined table, or a predetermined map.

7. The method of claim 6, wherein the first and second light sources are selected from the group consisting of,

wherein the engine is configured to operate according to the primary or secondary corrected air amount; and is

Wherein a predetermined formula, a predetermined table, or a predetermined map stored in the controller is learning-corrected to determine or correct the air amount according to the amount of oxygen contained in the exhaust gas discharged from the engine.

8. The method of claim 1, wherein the controller comprises:

a processor; and

a non-transitory storage medium having recorded thereon and executed by the processor a program for performing the method of claim 1.

9. A non-transitory storage medium having recorded thereon a program for executing the method of claim 1.

10. A decontamination system for a vehicle, the decontamination system comprising:

a canister connected to an intake pipe of the engine through a purge line;

a purge control valve installed in the purge line;

a purge pump installed on a purge line between the purge control valve and the canister;

a sensor installed in the intake pipe; and

a controller electrically connected to the sensor and configured to:

checking whether the engine is operating in an idle state;

determining an amount of air reaching a combustion chamber of the engine in response to a signal received from the sensor while the engine is operating in an idle state;

checking whether the evaporation gas collected in the canister is introduced into the intake pipe when the engine is operating in an idle state;

estimating an amount of the boil-off gas introduced into the intake pipe when the boil-off gas is determined to be introduced into the intake pipe, and primarily correcting the air amount according to the estimated amount of the boil-off gas;

checking whether an open holding time of an intake valve in the engine is changed due to an operation of a continuously variable valve duration system electrically connected to the controller; and is

When the open holding time of an intake valve in the engine is changed due to the operation of a continuous variable valve duration system, a correction variable is obtained based on the operation load of the continuous variable valve duration system, and the primarily corrected air amount is secondarily corrected in accordance with the correction variable.

11. The purification system according to claim 10, wherein the controller is configured to estimate the amount of the boil-off gas in accordance with an operation load of the purification pump.

12. The purification system as set forth in claim 10,

wherein, in checking whether the engine is operating in the idle state, the controller is configured to check whether a temperature of a coolant of the engine is higher than or equal to a predetermined value, and

wherein the controller interrupts an evaporated gas purge process of the purge system or an operation of the continuously variable valve duration system when it is determined that the engine is not in the idle state or the temperature of the coolant is lower than the predetermined value.

13. The purification system of claim 10, wherein the sensor comprises:

a hot film air mass flow sensor located between the air filter and the throttle; and

a manifold absolute pressure sensor located between the throttle valve and the combustion chamber.

14. The purification system of claim 10, further comprising:

a first pressure sensor mounted on a purge line between the canister and the purge pump;

and a second pressure sensor installed on a purge line between the purge pump and the purge control valve.

15. The purge system of claim 14, wherein the controller is configured to estimate the amount of the boil-off gas based on a number of revolutions per minute of the purge pump, opening and closing timings of the purge control valve, an opening amount of the purge control valve, a signal generated from the first pressure sensor, and a signal generated from the second pressure sensor.

16. The purification system according to claim 10, wherein deriving the correcting variable based on the operating load of the continuously variable valve duration system by the controller includes: the correcting variable is obtained by the controller by substituting the operation load of the continuously variable valve duration system into a predetermined formula, a predetermined table, or a predetermined map.

17. The purification system as set forth in claim 16,

wherein the motive mechanism is configured to operate in accordance with a primary or secondary corrected air quantity; and is

Wherein a predetermined formula, a predetermined table, or a predetermined map stored in the controller is learning-corrected to determine or correct the air amount according to the amount of oxygen contained in the exhaust gas discharged from the engine.

Technical Field

The present invention relates to a method of determining an amount of air in an active purging system. More particularly, the present invention relates to a method of determining an amount of air in an active purge system, which can prevent misfire even if a evaporative gas is purged or a Continuously Variable Valve Duration (CVVD) system is operated when an operating state of an engine is changed from an idle state to a part load state.

Background

The ratio of the intake air and the fuel at which the fuel is completely and chemically burned in the combustion chamber is called a theoretical air-fuel ratio (air-fuel ratio). In order to produce combustion in the combustion chamber that satisfies the stoichiometric air-fuel ratio, it is necessary to measure the intake air amount and supply fuel according to the intake air amount.

Fig. 1 is a schematic diagram showing an engine provided with a Manifold Absolute Pressure (MAP) sensor between a throttle valve and a combustion chamber. As shown in fig. 1, fuel is injected according to the intake air amount measured by the MAP sensor. In the present case, it is assumed that air passing through the throttle valve reaches the combustion chamber.

FIG. 2 is a schematic illustrating an engine with Exhaust Gas Recirculation (EGR). When the engine employs EGR, the intake air amount may be determined by an air mass flow (HFM) sensor disposed between an air filter and a throttle valve or by a MAP sensor disposed between the throttle valve and a combustion chamber. Even in the present case, it is assumed that air passing through the throttle valve reaches the combustion chamber.

However, when the engine is switched from the idle state to the part load state or from the part load state to the idle state, air passing through the throttle valve does not continuously reach the combustion chamber according to the Revolutions Per Minute (RPM) of the engine and the opening and closing timings of the intake and exhaust valves.

In the present case, when fuel is injected according to the intake air amount determined by the HFM sensor or the MAP sensor, the λ value (actual air-fuel ratio/theoretical air-fuel ratio) is less than 1 (rich) or greater than 1 (lean), and misfire may occur.

In order to prevent misfire, fuel is injected according to the determined intake air amount so that the λ value becomes in the range of 0.7 to 0.9.

Simultaneously, boil-off gas is collected in the canister. The boil-off gas can be appropriately treated according to the boil-off gas regulation. In the case of a hybrid vehicle or a plug-in hybrid vehicle, it is attempted to minimize the engine load by processing the boil-off gas before and after the start, and to improve the energy efficiency by adding a motor drive portion.

In addition, in order to improve fuel efficiency, there is a tendency to apply a Continuously Variable Valve Duration (CVVD) system configured to control the opening holding times of intake and exhaust valves to a hybrid vehicle or a plug-in hybrid vehicle.

However, since the boil-off gas reaches the combustion chamber during the boil-off gas treatment, the λ value decreases. According to the operation of the CVVD system, the amount of intake air to the combustion chamber may be reduced or increased, and the amount of exhaust gas remaining in the combustion chamber may be reduced or increased.

That is, when the operating state of the engine of the hybrid vehicle or the plug-in hybrid vehicle is changed from an idle state to a partial load state and evaporation gas is treated or a CVVD system is operated, the general method of preventing misfire by injecting a large amount of fuel does not prevent misfire and more exhaust gas may be generated.

The information contained in the background section of this invention is only for enhancement of understanding of the general background of the invention and is not to be construed as an acknowledgement or any form of suggestion that this information constitutes prior art known to a person skilled in the art.

Disclosure of Invention

Various aspects of the present invention are directed to provide a method of determining an amount of air in an active purge system, which can prevent misfire even if an evaporation gas is purged or a Continuously Variable Valve Duration (CVVD) system is operated when an operating state of an engine is changed from an idle state to a partial load state.

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

According to various exemplary embodiments of the present invention, there is provided a method of determining an amount of air in a purification system, including: checking, by a controller, whether an engine is operating in an idle state; determining, by a controller, an amount of air reaching a combustion chamber of an engine in response to a signal received from a sensor provided in an intake pipe; checking, by the controller, whether the boil-off gas collected in the canister is introduced into the intake pipe; estimating, by the controller, an amount of the boil-off gas introduced into the intake pipe when the boil-off gas is determined to be introduced into the intake pipe, and arithmetically primarily correcting an air amount determined according to the estimated amount of the boil-off gas; checking, by a controller, whether an open holding time of an intake valve in an engine is changed due to an operation of a continuously variable valve duration CVVD system electrically connected to the controller; and obtaining, by the controller, a correction variable by substituting the operation load of the CVVD system into a predetermined formula, a predetermined table, or a predetermined map, and arithmetically performing secondary correction on the primarily corrected air amount according to the correction variable.

In addition, the controller may check whether the temperature of the coolant of the engine is higher than or equal to a predetermined value when checking whether the engine is operated in an idle state, and may interrupt the operation of the boil-off gas purge process or the CVVD system when the engine is not in the idle state or the temperature of the coolant is lower than the predetermined value.

In addition, the sensor may include: a hot film air mass flow (HFM) sensor located between the air filter and the throttle; and a Manifold Absolute Pressure (MAP) sensor located between the throttle and the combustion chamber.

In addition, the canister may be connected to the intake pipe through a purge line, a purge control valve may be provided on the purge line, a purge pump may be directly provided with the purge control valve and the purge line, a first pressure sensor may be provided between the canister and the purge pump, a second pressure sensor may be provided between the purge pump and the purge control valve, and the controller may estimate the amount of the evaporation gas according to an operation load of the purge pump.

In addition, the controller may estimate the amount of the evaporation gas based on the number of RPMs of the purge pump, opening and closing timings (timing) of the purge control valve, an opening amount of the purge control valve, a signal generated from the first pressure sensor, and a signal generated from the second pressure sensor.

In addition, the engine mechanism may be operated according to the primary or secondary corrected air amount; and to determine or correct the air amount from the amount of oxygen contained in the exhaust gas discharged from the engine, learning correction may be performed on a formula, a table, or a map stored in the controller.

The method and apparatus of the present invention have other features and advantages which will be apparent from or are set forth in more detail in the accompanying drawings, which are incorporated herein, and the following detailed description, which together with the drawings, illustrate certain principles of the invention.

Drawings

FIG. 1 is an exemplary diagram illustrating an engine having a Manifold Absolute Pressure (MAP) sensor.

FIG. 2 is an exemplary diagram illustrating an engine to which Exhaust Gas Recirculation (EGR) may be applied.

Fig. 3 is a flowchart illustrating a method of determining an amount of air in an active purging system according to an exemplary embodiment of the present invention.

Fig. 4 is a system illustrating application of the method of fig. 3 for determining the amount of air in an active purging system.

It should be understood that the drawings are not necessarily to scale, presenting a somewhat simplified representation of various features illustrative of the basic principles of the invention. The particular design features of the present invention, including, for example, particular dimensions, orientations, locations, and shapes, incorporated herein will be determined in part by the particular design application and use environment.

In the drawings, like reference characters designate like or equivalent parts throughout the several views.

Detailed Description

Reference will now be made in detail to the various embodiments of the invention, examples of which are illustrated in the accompanying drawings and described below. While the invention will be described in conjunction with the exemplary embodiments of the invention, it will be understood that the description is not intended to limit the invention to those exemplary embodiments. On the other hand, the present invention is intended to cover not only exemplary embodiments of the present invention but also various alternatives, modifications, equivalents and other embodiments, which may be included within the spirit and scope of the present invention as defined by the appended claims.

Hereinafter, a method of determining an amount of air in an active purging system according to an exemplary embodiment of the present invention will be described with reference to the accompanying drawings.

As shown in fig. 3, the method of determining the amount of air in an active purge system according to an exemplary embodiment of the present invention includes: checking by the controller 100 whether the engine 200 is operated in an idle state (S100); determining, by the controller 100, an amount of air reaching the combustion chamber 210 of the engine in response to a signal received from a sensor provided in an intake pipe of the engine 300 (S200); checking, by the controller 100, whether the evaporation gas collected in the canister 500 is introduced into the intake pipe 300 (S300); estimating, by the controller 100, an amount of the boil-off gas introduced into the intake pipe 300 when the boil-off gas is determined to be introduced into the intake pipe 300, and arithmetically primarily correcting an air amount determined according to the estimated amount of the boil-off gas (S400); checking, by the controller 100, whether an open holding time of an intake valve in the engine is changed due to an operation of a Continuous Variable Valve Duration (CVVD) system 400 (S500); and obtaining a correction variable by the controller 100 by substituting the operation load of the CVVD system 400 into a predetermined formula, a predetermined table, or a predetermined map, and arithmetically performing secondary correction on the primarily corrected air amount according to the correction variable (S600).

The idle speed means a state where the engine 200 is continuously operated at the lowest number of revolutions, and the part load means a state where the torque generated by the engine 200 is less than the maximum torque that can be generated. The torque of the engine 200 is measured in real time in the transmission.

Preferably, in checking whether the engine 200 is operated in the idle state (S100), the controller 100 checks whether the temperature of the coolant of the engine 200 is higher than or equal to a predetermined value. When the engine 200 is not in the idle state or the temperature of the coolant is lower than a predetermined value, the controller 100 interrupts the evaporation gas purification process or the operation of the CVVD system 400. In the present case, the predetermined value is 50 degrees celsius. When the temperature of the coolant is lower than a predetermined value, the controller 100 determines a cold state. In the cold state, since the combustion characteristics and the generated exhaust gas are different from those in the hot state, the evaporation gas purge or the operation of the CVVD system 400 is prohibited in the cold state.

The sensor includes: a hot film air mass flow (HFM) sensor 310 between the air filter and the throttle, and a manifold absolute pressure sensor (MAP)320 between the throttle and the combustion chamber 210. The controller 100 receives signals from both the HFM sensor 310 and the MAP sensor 320. The controller 100 obtains a rotation angle of the cam, a rotation angle of the crankshaft, a fuel injection pressure, and the like from signals received through various sensors provided in the vehicle.

In checking whether the boil-off gas collected in the canister 500 is introduced into the intake pipe 300 (S300), when the boil-off gas is checked as not being introduced into the intake pipe 300, the controller 100 performs a check whether the open holding time of the intake valve is changed due to the operation of the CVVD system 400 (S500).

In addition, when it is checked whether the open holding time of the intake valve is changed due to the operation of the CVVD system 400 (S500), the controller 100 determines that the engine 200 is not switched from the idle state to the part load state when the CVVD system 400 is not operated.

Meanwhile, the system shown in fig. 4 applies the method of determining the amount of air in the active purge system according to an exemplary embodiment of the present invention. As shown in fig. 4, the canister 500 is connected to the intake pipe 300 through a purge line 600. A purge control valve 610 is provided in the purge line 600. A purge pump 620 is provided between the purge control valve 610 and the purge line 600. A first pressure sensor 630 is provided between the tank 500 and the purge pump 620. A second pressure sensor 640 is provided between the purge pump 620 and the purge control valve 610.

When the amount of the boil-off gas introduced into the intake pipe 300 is estimated by the controller 100 and the air amount determined according to the estimated amount of the boil-off gas is arithmetically primarily corrected (S400), the controller 100 estimates the amount of the boil-off gas according to the operation load of the purge pump 620. The controller 100 may estimate the amount of the evaporation gas based on the RPM number of the purge pump 620, the opening and closing timing of the purge control valve 610, the opening amount of the purge control valve 610, the signal generated from the first pressure sensor 630, and the signal generated from the second pressure sensor 640, in addition to the operation load of the purge pump 620.

The evaporation gas is compressed by the purge pump 620 between the purge pump 620 and the purge control valve 610. By controlling the opening and closing timings and the opening amount of the purge control valve 610, the compressed evaporation gas can be injected into the intake pipe 300. The amount of the boil-off gas injected into the intake pipe 300 can be controlled by controlling the degree of compression of the boil-off gas and the operation of the purge control valve 610.

The concentration and density of the boil-off gas may be determined according to a difference between the load and RPM number of the purge pump 620 and a difference between pressures measured by the first pressure sensor 630 and the second pressure sensor 640. The concentration, density, amount, and the like of the hydrocarbons contained in the boil-off gas, and the concentration, density, amount, and the like of the air contained in the boil-off gas can be estimated from the concentration or density of the boil-off gas.

Formulas, graphs, tables, and the like for determining the concentration, density, and amount of air or hydrocarbon contained in the boil-off gas are stored in the controller 100 as variables (e.g., the load and RPM number of the purge pump 620, the opening and closing timing and opening amount of the purge control valve 610, and the difference between the pressures measured by the first pressure sensor 630 and the second pressure sensor 640).

As shown in fig. 4, the CVVD system 400 is mounted on a camshaft. The CVVD system 400 controls the opening or closing operation of the intake valve or the exhaust valve according to the rotation angle of the camshaft.

When checking whether the open holding time of the intake valve is changed due to the operation of the CVVD system 400 (S500), the controller 100 checks the operation of the CVVD system 400.

The operation of the CVVD system 400 is checked by a signal transmitted from the CVVD system 400 to the controller 100 or a command signal transmitted from the controller 100 to the CVVD system 400 for performing the operation. The controller 100 receives signals from sensors provided in the engine 200 and the transmission, and checks whether the RPM number of the engine 200 increases and the torque increases.

When the CVVD system 400 is operated, the controller 100 performs the derivation of a correction variable by substituting the operation load of the CVVD system 400 into a formula, a table, or a map set in advance, and arithmetically performs secondary correction on the primarily corrected air amount according to the correction variable (S600).

The operational load of the CVVD system 400 means the magnitude of voltage, power, and current changes applied to the operation of the CVVD system 400. The operation load of the CVVD system 400 is substituted into a conversion formula set in advance, or into a conversion map, a conversion table, or the like, and converted into a correction variable of the air amount. For example, the correction variable of the air amount may be a value obtained by multiplying the operation load of the CVVD system by 0.001.

Meanwhile, fuel is supplied according to the air amount, and the engine 200 is operated. The controller 100 continuously obtains the amount of oxygen contained in the exhaust gas discharged from the engine 200 based on a signal received from a lambda sensor 220 provided in the exhaust pipe. The controller 100 determines whether lean combustion or rich combustion occurs based on the obtained oxygen amount. In addition, the controller 100 corrects a formula, a table, or a map stored in the controller 100 as a calculation or correction model in order to determine or correct the air amount according to a set target so that the rich burn or the lean burn can be generated.

As described above, according to the method of determining the amount of air in the active purge system according to the exemplary embodiment of the present invention, the controller 100 determines the amount of air reaching the combustion chamber 210 in response to a signal received from a sensor provided in the intake pipe 300; estimating the amount of boil-off gas reaching the combustion chamber 210 during the boil-off gas treatment; primarily correcting the air amount based on the estimated amount of the boil-off gas; and secondarily corrects the air amount according to the degree of operation of the CVVD system 400 when the CVVD system 400 is operated.

Therefore, when the state of the engine 200 is switched from the idle state to the part load state, the evaporated gas is processed, or even when the CVVD system 400 is operated, the determined air amount can be appropriately corrected, and the λ value can be controlled so that combustion close to the stoichiometric air-fuel ratio can be generated. Therefore, when the state of the engine 200 is switched from the idle state to the partial load state, misfire can be prevented, and excessive exhaust gas discharge can be prevented.

As described above, according to the method of determining the amount of air in the active purge system according to the exemplary embodiment of the present invention, the controller may determine the amount of air reaching the combustion chamber of the engine in response to a signal received from a sensor provided in the intake pipe; estimating an amount of boil-off gas reaching the combustion chamber during the boil-off gas treatment; primarily correcting the air amount based on the estimated amount of the boil-off gas; and when a Continuous Variable Valve Duration (CVVD) system is operated, secondarily correcting the primarily corrected air amount according to an operation degree of the CVVD system.

Therefore, when the state of the engine is switched from the idling state to the partial load state, the evaporated gas can be processed, or even when the CVVD system is operated, the estimated air amount can be appropriately corrected, and the λ value can be controlled so that combustion close to the stoichiometric air-fuel ratio can be produced. Therefore, when the state of the engine is switched from the idle state to the partial load state, misfire can be prevented, and excessive discharge of exhaust gas can be prevented.

Additionally, the term "controller" refers to a hardware device that includes a processor and memory configured to perform one or more steps interpreted as an algorithmic structure. The memory may be a non-transitory storage medium including program instructions that store algorithm steps, and the processor executes the algorithm steps to perform one or more processes of the methods according to various exemplary embodiments of the present invention. A controller according to an exemplary embodiment of the present disclosure may be implemented by a non-volatile memory configured to store an algorithm for controlling operations of various components of a vehicle or data regarding program instructions for executing the algorithm, and a processor configured to perform the operations described above using the data stored in the memory. The memory and the processor may be separate chips. Alternatively, the memory and processor may be integrated in a single chip. A processor may be implemented as one processor or as multiple processors.

The controller may be at least one microprocessor operated by a predetermined program, which may include a series of commands for performing the method according to various exemplary embodiments of the present invention.

The foregoing invention can also be embodied as computer readable codes on a computer readable recording medium. The computer readable recording medium is any data storage device that can store data which can be thereafter read by a computer system. Examples of the computer readable recording medium include a Hard Disk Drive (HDD), a Solid State Disk (SSD), a Silicon Disk Drive (SDD), a Read Only Memory (ROM), a Random Access Memory (RAM), a CD-ROM, a magnetic tape, a floppy disk, an optical data storage device, etc., and are implemented as a carrier wave (e.g., transmission through the internet).

For convenience in explanation and accurate definition in the appended claims, the terms "upper", "lower", "inner", "outer", "upper", "lower", "upward", "downward", "front", "rear", "back", "inside", "outside", "inward", "outward", "inner", "outer", "forward", "rearward" are used to describe features of the exemplary embodiments with reference to the positions of such features as displayed in the figures. It is also to be understood that the term "coupled" or its derivatives refer to both direct and indirect connections.

The foregoing descriptions of specific exemplary embodiments of the present invention have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the invention to the precise embodiments disclosed, and obviously many modifications and variations are possible in light of the above teaching. The exemplary embodiments were chosen and described in order to explain certain principles of the invention and its practical application to enable others skilled in the art to make and utilize various exemplary embodiments of the invention, as well as alternatives and modifications thereof. It is intended that the scope of the invention be defined by the claims and the like appended hereto.