阅读说明：本技术 发动机机油温度计算方法 (Engine oil temperature calculation method ) 是由 刘文彬 胡璋林 周璐 温敏 徐洪伟 侯金 于 2021-08-05 设计创作，主要内容包括：本发明公开了一种发动机机油温度计算方法,包括：基于环境温度、发动机水温和停机时间计算初始化阶段的机油温度；基于环境温度和发动机水温计算暖机阶段的机油温度；基于环境温度、发动机水温、发动机转速、发动机进气流量和整车车速计算发动机正常运转阶段的机油温度。本发明的发动机机油温度计算方法,分阶段地计算机油温度,考虑到车辆实际驾驶中的变工况,在不同的阶段基于不同的影响因素计算机油温度,实现机油温度的虚拟计算,并经过实车标定、测试达到机油温度等同实际传感器测量温度的效果,既能有效节约成本又能准确获取发动机油温参数。(The invention discloses a method for calculating engine oil temperature, which comprises the following steps: calculating the engine oil temperature in the initialization stage based on the environment temperature, the engine water temperature and the shutdown time; calculating the engine oil temperature in the warm-up stage based on the ambient temperature and the engine water temperature; and calculating the engine oil temperature of the engine in the normal operation stage based on the ambient temperature, the engine water temperature, the engine rotating speed, the engine intake flow and the vehicle speed of the whole vehicle. The engine oil temperature calculating method of the engine calculates the engine oil temperature in stages, calculates the engine oil temperature based on different influence factors in different stages by considering variable working conditions in actual driving of a vehicle, realizes virtual calculation of the engine oil temperature, achieves the effect of the engine oil temperature being equal to the actual sensor measuring temperature through actual vehicle calibration and test, and can effectively save cost and accurately obtain the engine oil temperature parameters.)

1. An engine oil temperature calculation method, characterized by comprising:

calculating the engine oil temperature in the initialization stage based on the environment temperature, the engine water temperature and the shutdown time;

calculating the engine oil temperature in the warm-up stage based on the ambient temperature and the engine water temperature;

and calculating the engine oil temperature of the engine in the normal operation stage based on the ambient temperature, the engine water temperature, the engine rotating speed, the engine intake flow and the vehicle speed of the whole vehicle.

2. The engine oil temperature calculation method according to claim 1, wherein calculating the oil temperature in the initialization stage based on the ambient temperature, the engine water temperature and the downtime specifically comprises:

obtaining the downtime;

when the shutdown time is greater than a preset shutdown time threshold value, calculating an engine oil temperature basic value in an initialization stage, and taking the engine oil temperature basic value as an oil temperature value;

and when the shutdown time is less than or equal to a preset shutdown time threshold value, calculating an engine oil temperature basic value and an engine oil temperature correction value in an initialization stage, and calculating an oil temperature value according to the engine oil temperature basic value and the engine oil temperature correction value.

3. The engine oil temperature calculation method according to claim 2, wherein in the case that the downtime is greater than the preset downtime threshold, the calculating the oil temperature base value in the initialization stage and using the oil temperature base value as the oil temperature value specifically comprises:

The base value of the oil temperature is calculated by the following formula,

Toil＝Toil_base

toil _ base ═ (1-correction factor 1) × water temperature + ambient temperature × correction factor 1 (1)

Wherein, Toil represents an oil temperature value, Toil _ base represents an engine oil temperature basic value, a correction coefficient 1 is a calibratable constant and represents a distribution coefficient of water temperature and ambient temperature, and the correction coefficient 1 is calibrated according to different ambient temperatures and water temperature values of an engine after a vehicle is left stand for a long time.

4. The engine oil temperature calculation method according to claim 2, wherein, in a case that the downtime is less than or equal to a preset downtime threshold, the calculating the base oil temperature value and the corrected oil temperature value in the initialization stage, and calculating the oil temperature value according to the base oil temperature value and the corrected oil temperature value specifically comprises:

the base value of the oil temperature is calculated by the following formula,

toil _ base ═ (1-correction factor 1) × water temperature + ambient temperature × correction factor 1 (2)

Wherein, Toil _ base represents the engine oil temperature basic value, the correction coefficient 1 is a calibratable constant and represents the distribution coefficient of water temperature and environment temperature, and the correction coefficient 1 is calibrated according to different environment temperatures and water temperature values of an engine after a vehicle is stood for a long time;

The oil temperature correction value is calculated by the following formula,

Toil_cf＝A+B

a ═ toilstp × correction coefficient 2+ ambient temperature × (1-correction coefficient 2) ] × correction coefficient 3

B ═ toilstp × correction coefficient 4+ water temperature × (1-correction coefficient 4) ] × (1-correction coefficient 3) (3)

Wherein Toil _ cf represents an engine oil temperature correction value, toilstp represents the engine oil temperature at the last shutdown, a correction coefficient 2 is a one-dimensional table calibration quantity associated with the shutdown time, a correction coefficient 3 is a calibratable constant and represents a distribution coefficient of the influence of the water temperature and the ambient temperature on the oil temperature in the shutdown process, and a correction coefficient 4 is a calibratable constant and is an influence coefficient of the water temperature on the oil temperature in the shutdown process;

calculating the oil temperature value according to the base value and the corrected value of the oil temperature by the following formula,

Toil＝Toil_base+Toil_cf (4)

wherein, Toil represents an oil temperature value, Toil _ base represents an engine oil temperature basic value, and Toil _ cf represents an engine oil temperature correction value.

5. The engine oil temperature calculation method according to claim 1, wherein the calculating the oil temperature in the warm-up stage based on the ambient temperature and the engine water temperature specifically comprises:

the oil temperature at the warm-up stage is calculated by the following formula,

toil ═ 1-correction factor 1) × water temperature + ambient temperature × correction factor 1 (5)

Wherein, Toil represents the oil temperature value, the correction coefficient 1 is a calibratable constant and represents the distribution coefficient of water temperature and environment temperature, and the correction coefficient 1 is calibrated according to different environment temperatures and water temperature values of an engine after a vehicle is stood for a long time.

6. The engine oil temperature calculation method according to claim 1, wherein the calculating the engine oil temperature in the normal operation stage of the engine based on the ambient temperature, the engine water temperature, the engine rotation speed, the engine intake air flow rate and the vehicle speed of the whole vehicle specifically comprises:

when the water temperature of the engine exceeds a preset water temperature threshold value, the engine enters a normal operation stage, and the engine oil temperature of the engine in the normal operation stage is calculated through the following formula;

toil (100 (degree. C.). times.5 correction coefficient. times.6 correction coefficient. times.7 (6))

Wherein Toil represents an oil temperature value, the correction coefficient 5 is a one-dimensional standard quantity related to the ambient temperature, the correction coefficient 6 is a one-dimensional standard quantity related to the engine speed, and the correction coefficient 7 is a two-dimensional standard quantity related to the engine intake air flow and the vehicle speed of the whole vehicle.

7. The engine oil temperature calculation method according to claim 1, further comprising:

When the sensor fails, the oil temperature is calculated.

8. The engine oil temperature calculation method according to claim 7, wherein in the case of a failure of an engine ambient temperature sensor, the calculating of the oil temperature specifically comprises:

the oil temperature is calculated by the following formula,

toil-water temperature x correction factor 8 (7)

Wherein, Toil represents the oil temperature value, and the correction coefficient 8 is a calibratable constant;

and (4) lightening an engine fault lamp and reporting an engine environment temperature fault code.

9. The engine oil temperature calculation method according to claim 7, wherein in the case where the engine water temperature sensor fails, the calculating the oil temperature specifically includes:

the oil temperature is calculated by the following formula,

toil default (8)

Wherein, Toil represents an oil temperature value, and a default value is a calibratable constant;

and (4) lighting an engine fault lamp and reporting an engine water temperature fault code.

Technical Field

The invention relates to the technical field of automobile engine system control, in particular to an engine oil temperature calculation method.

Background

For an automobile engine, engine oil is equivalent to automobile blood, and has functions of cleaning, cooling, protecting, sealing and the like besides the function of lubricating engine parts. With the requirements of regulation upgrading and environmental protection and the requirement of improving the driving experience performance of the whole vehicle, the engine control becomes more and more refined, and in an engine electric control system, the engine oil temperature is used as an input parameter for Variable Timing Valve (VVT) control, engine resistance compensation and the like, so that the function of the engine oil temperature in the electric control system becomes more important. How to effectively save cost and accurately obtain the oil temperature parameters of the engine is a subject in the field of engine control.

Therefore, a method for calculating engine oil temperature is needed.

Disclosure of Invention

The invention aims to provide an engine oil temperature calculation method, which aims to solve the problems in the prior art, can calculate the oil temperature based on different influence factors at different stages by considering the variable working conditions in the actual driving of a vehicle, and realizes the virtual calculation of the oil temperature.

The invention provides a method for calculating engine oil temperature, which comprises the following steps:

calculating the engine oil temperature in the initialization stage based on the environment temperature, the engine water temperature and the shutdown time;

calculating the engine oil temperature in the warm-up stage based on the ambient temperature and the engine water temperature;

and calculating the engine oil temperature of the engine in the normal operation stage based on the ambient temperature, the engine water temperature, the engine rotating speed, the engine intake flow and the vehicle speed of the whole vehicle.

The engine oil temperature calculation method as described above, wherein preferably, the calculating the oil temperature in the initialization stage based on the ambient temperature, the engine water temperature, and the downtime specifically includes:

obtaining the downtime;

when the shutdown time is greater than a preset shutdown time threshold value, calculating an engine oil temperature basic value in an initialization stage, and taking the engine oil temperature basic value as an oil temperature value;

And when the shutdown time is less than or equal to a preset shutdown time threshold value, calculating an engine oil temperature basic value and an engine oil temperature correction value in an initialization stage, and calculating an oil temperature value according to the engine oil temperature basic value and the engine oil temperature correction value.

The method for calculating the engine oil temperature as described above, wherein preferably, when the downtime is greater than a preset downtime threshold, the calculating the base value of the engine oil temperature in the initialization stage, and taking the base value of the engine oil temperature as the oil temperature value specifically includes:

the base value of the oil temperature is calculated by the following formula,

Toil＝Toil_base

toil _ base ═ (1-correction factor 1) × water temperature + ambient temperature × correction factor 1 (1)

Wherein, Toil represents an oil temperature value, Toil _ base represents an engine oil temperature basic value, a correction coefficient 1 is a calibratable constant and represents a distribution coefficient of water temperature and ambient temperature, and the correction coefficient 1 is calibrated according to different ambient temperatures and water temperature values of an engine after a vehicle is left stand for a long time.

The method for calculating the engine oil temperature as described above, wherein preferably, when the downtime is less than or equal to the preset downtime threshold, the calculating the base value of the engine oil temperature and the correction value of the engine oil temperature in the initialization stage, and calculating the oil temperature value according to the base value of the engine oil temperature and the correction value of the engine oil temperature includes:

The base value of the oil temperature is calculated by the following formula,

toil _ base ═ (1-correction factor 1) × water temperature + ambient temperature × correction factor 1 (2)

Wherein, Toil _ base represents the engine oil temperature basic value, the correction coefficient 1 is a calibratable constant and represents the distribution coefficient of water temperature and environment temperature, and the correction coefficient 1 is calibrated according to different environment temperatures and water temperature values of an engine after a vehicle is stood for a long time;

the oil temperature correction value is calculated by the following formula,

Toil_cf＝A+B

a ═ toilstp × correction coefficient 2+ ambient temperature × (1-correction coefficient 2) ] × correction coefficient 3

B ═ toilstp × correction coefficient 4+ water temperature × (1-correction coefficient 4) ] × (1-correction coefficient 3) (3)

Wherein Toil _ cf represents an engine oil temperature correction value, toilstp represents the engine oil temperature at the last shutdown, a correction coefficient 2 is a one-dimensional table calibration quantity associated with the shutdown time, a correction coefficient 3 is a calibratable constant and represents a distribution coefficient of the influence of the water temperature and the ambient temperature on the oil temperature in the shutdown process, and a correction coefficient 4 is a calibratable constant and is an influence coefficient of the water temperature on the oil temperature in the shutdown process;

calculating the oil temperature value according to the base value and the corrected value of the oil temperature by the following formula,

Toil＝Toil_base+Toil_cf (4)

wherein, Toil represents an oil temperature value, Toil _ base represents an engine oil temperature basic value, and Toil _ cf represents an engine oil temperature correction value.

The engine oil temperature calculation method as described above, wherein preferably, the calculating the oil temperature in the warm-up stage based on the ambient temperature and the engine water temperature specifically includes:

the oil temperature at the warm-up stage is calculated by the following formula,

toil ═ 1-correction factor 1) × water temperature + ambient temperature × correction factor 1 (5)

Wherein, Toil represents the oil temperature value, the correction coefficient 1 is a calibratable constant and represents the distribution coefficient of water temperature and environment temperature, and the correction coefficient 1 is calibrated according to different environment temperatures and water temperature values of an engine after a vehicle is stood for a long time.

The engine oil temperature calculation method as described above, wherein preferably, the calculating the engine oil temperature in the normal operation stage of the engine based on the ambient temperature, the engine water temperature, the engine rotation speed, the engine intake air flow rate, and the vehicle speed of the whole vehicle specifically includes:

when the water temperature of the engine exceeds a preset water temperature threshold value, the engine enters a normal operation stage, and the engine oil temperature of the engine in the normal operation stage is calculated through the following formula;

toil (100 (degree. C.). times.5 correction coefficient. times.6 correction coefficient. times.7 (6))

Wherein Toil represents an oil temperature value, the correction coefficient 5 is a one-dimensional standard quantity related to the ambient temperature, the correction coefficient 6 is a one-dimensional standard quantity related to the engine speed, and the correction coefficient 7 is a two-dimensional standard quantity related to the engine intake air flow and the vehicle speed of the whole vehicle.

The engine oil temperature calculation method as described above, wherein preferably, the engine oil temperature calculation method further includes:

when the sensor fails, the oil temperature is calculated.

The engine oil temperature calculation method as described above, wherein preferably, in the case where the engine ambient temperature sensor fails, the calculating of the oil temperature specifically includes:

the oil temperature is calculated by the following formula,

toil-water temperature x correction factor 8 (7)

Wherein, Toil represents the oil temperature value, and the correction coefficient 8 is a calibratable constant;

and (4) lightening an engine fault lamp and reporting an engine environment temperature fault code.

The method for calculating the engine oil temperature as described above, wherein preferably, in the case where the engine water temperature sensor fails, the calculating the engine oil temperature specifically includes:

the oil temperature is calculated by the following formula,

toil default (8)

Wherein, Toil represents an oil temperature value, and a default value is a calibratable constant;

and (4) lighting an engine fault lamp and reporting an engine water temperature fault code.

The invention provides an engine oil temperature calculating method, which calculates the engine oil temperature by stages, calculates the engine oil temperature based on different influence factors in different stages by considering variable working conditions in the actual driving of a vehicle, realizes the virtual calculation of the engine oil temperature, achieves the effect of the engine oil temperature being equal to the actual sensor measuring temperature through the actual vehicle calibration and test, can effectively save the cost and can accurately obtain the engine oil temperature parameter; and the engine oil temperature value is calculated under the condition of sensor failure, so that the engine oil temperature cannot be obtained when the sensor fails.

Drawings

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be further described with reference to the accompanying drawings, in which:

FIG. 1 is a flowchart of an embodiment of a method for calculating engine oil temperature according to the present invention.

Detailed Description

Various exemplary embodiments of the present disclosure will now be described in detail with reference to the accompanying drawings. The description of the exemplary embodiments is merely illustrative and is in no way intended to limit the disclosure, its application, or uses. The present disclosure may be embodied in many different forms and is not limited to the embodiments described herein. These embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art. It should be noted that: the relative arrangement of parts and steps, the composition of materials, numerical expressions and numerical values set forth in these embodiments are to be construed as merely illustrative, and not as limitative, unless specifically stated otherwise.

As used in this disclosure, "first", "second": and the like, do not denote any order, quantity, or importance, but rather are used to distinguish one element from another. The word "comprising" or "comprises", and the like, means that the element preceding the word covers the element listed after the word, and does not exclude the possibility that other elements are also covered. "upper", "lower", and the like are used merely to indicate relative positional relationships, and when the absolute position of the object being described is changed, the relative positional relationships may also be changed accordingly.

In the present disclosure, when a specific component is described as being located between a first component and a second component, there may or may not be intervening components between the specific component and the first component or the second component. When it is described that a specific component is connected to other components, the specific component may be directly connected to the other components without having an intervening component, or may be directly connected to the other components without having an intervening component.

All terms (including technical or scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs unless specifically defined otherwise. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

Techniques, methods, and apparatus known to those of ordinary skill in the relevant art may not be discussed in detail, but are intended to be part of the specification where appropriate.

How to effectively save cost and accurately obtain the oil temperature parameters of the engine is a subject in the field of engine control.

The current oil temperature calculation method comprises an initial value calculation step, a final value calculation step, a filtering time constant calculation step and a filtering function realization step. The initial value is calculated by acquiring the stop time and stop engine oil temperature data of a plurality of groups of engines according to the difference value of the measured water temperature and the measured air inlet temperature when the engine is started, and calibrating the initial engine oil temperature. The final value is calculated as the maximum value that can be reached by calculating the engine oil temperature under fixed operating conditions. The filter time constant is calculated as a calculation of a rate of change of the oil temperature. The filtering function is realized by substituting the calculated values of the previous three steps into a real-time engine oil temperature formula obtained through mathematical modeling to calculate a real-time engine oil temperature value.

The existing oil temperature calculation method mainly has the following defects that firstly, the influence of ambient temperature, the speed of the whole vehicle and the air input of an engine is not considered, the influence of factors such as the stop time of the engine, the ambient temperature and the like on the initialization of the oil temperature is not considered, and no related algorithm is used for supporting the calculation of the oil temperature; secondly, in the prior art, the transition is carried out by calculating an initial value and a final value of the engine oil temperature and filtering in the process, the difference of the influence factors of the engine in a warm-up stage and a normal operation stage is not considered, meanwhile, the final value is the maximum value which can be reached by the engine oil temperature under a fixed working condition (fixed rotating speed and load), the calculation method is rough, the difference from the variable working condition in the actual driving of the vehicle is large, and the calculated value and the actual value of the model are easy to have large deviation; finally, the prior art does not consider the way in which the sensors used fail.

As shown in fig. 1, the engine oil temperature calculation method provided in this embodiment specifically includes the following steps in an actual implementation process:

step S1, calculating the oil temperature in the initialization phase based on the ambient temperature, the engine water temperature, and the downtime.

In an embodiment of the engine oil temperature calculating method of the present invention, the step S1 may specifically include:

and step S11, acquiring the shutdown time.

And step S12, when the shutdown time is larger than the preset shutdown time threshold value, calculating an engine oil temperature basic value in the initialization stage, and taking the engine oil temperature basic value as an oil temperature value.

When the downtime is greater than the preset downtime threshold, the step S12 specifically includes:

the base value of the oil temperature is calculated by the following formula,

Toil＝Toil_base

toil _ base ═ (1-correction factor 1) × water temperature + ambient temperature × correction factor 1 (1)

Wherein, Toil represents an oil temperature value, Toil _ base represents an engine oil temperature basic value, a correction coefficient 1 is a calibratable constant and represents a distribution coefficient of water temperature and ambient temperature, and the correction coefficient 1 is calibrated according to different ambient temperatures and water temperature values of an engine after a vehicle is left stand for a long time.

And step S13, when the stop time is less than or equal to the preset stop time threshold value, calculating an engine oil temperature basic value and an engine oil temperature correction value in the initialization stage, and calculating an oil temperature value according to the engine oil temperature basic value and the engine oil temperature correction value.

When the downtime is less than or equal to the preset downtime threshold, the step S13 specifically includes:

step S131, calculating an oil temperature basic value through the following formula,

toil _ base ═ (1-correction factor 1) × water temperature + ambient temperature × correction factor 1 (2)

Wherein, Toil _ base represents the engine oil temperature basic value, the correction coefficient 1 is a calibratable constant and represents the distribution coefficient of water temperature and ambient temperature, and the correction coefficient 1 is calibrated according to different ambient temperatures and water temperature values of the engine after the vehicle is left standing for a long time.

Step S132, calculating the oil temperature correction value through the following formula,

Toil_cf＝A+B

a ═ toilstp × correction coefficient 2+ ambient temperature × (1-correction coefficient 2) ] × correction coefficient 3

B ═ toilstp × correction coefficient 4+ water temperature × (1-correction coefficient 4) ] × (1-correction coefficient 3) (3)

Wherein Toil _ cf represents an engine oil temperature correction value, toilstp represents the engine oil temperature at the last shutdown, a correction coefficient 2 is a one-dimensional table calibration quantity associated with the shutdown time, a correction coefficient 3 is a calibratable constant and represents a distribution coefficient of the influence of the water temperature and the ambient temperature on the oil temperature in the shutdown process, and a correction coefficient 4 is a calibratable constant and is an influence coefficient of the water temperature on the oil temperature in the shutdown process. In a particular implementation, toilstp may be derived from the last shutdown oil temperature stored in the engine electronic control unit.

Step S133, calculating an oil temperature value according to the oil temperature basic value and the oil temperature correction value by the following formula,

Toil＝Toil_base+Toil_cf (4)

wherein, Toil represents an oil temperature value, Toil _ base represents an engine oil temperature basic value, and Toil _ cf represents an engine oil temperature correction value.

And step S2, calculating the oil temperature in the warm-up stage based on the environment temperature and the engine water temperature.

Specifically, the oil temperature at the warm-up stage is calculated by the following formula,

toil ═ 1-correction factor 1) × water temperature + ambient temperature × correction factor 1 (5)

Wherein, Toil represents the oil temperature value, the correction coefficient 1 is a calibratable constant and represents the distribution coefficient of water temperature and environment temperature, and the correction coefficient 1 is calibrated according to different environment temperatures and water temperature values of an engine after a vehicle is stood for a long time.

And step S3, calculating the engine oil temperature in the normal operation stage of the engine based on the environment temperature, the engine water temperature, the engine rotating speed, the engine intake air flow and the vehicle speed of the whole vehicle.

Specifically, when the water temperature of the engine exceeds a preset water temperature threshold value, the engine enters a normal operation stage, and the engine oil temperature of the engine in the normal operation stage is calculated through the following formula;

toil (100 (degree. C.). times.5 correction coefficient. times.6 correction coefficient. times.7 (6))

Wherein Toil represents an oil temperature value, the correction coefficient 5 is a one-dimensional standard quantity related to the ambient temperature, the correction coefficient 6 is a one-dimensional standard quantity related to the engine speed, and the correction coefficient 7 is a two-dimensional standard quantity related to the engine intake air flow and the vehicle speed of the whole vehicle.

Further, in some embodiments of the present invention, the engine oil temperature calculation method further includes:

and step S4, calculating the oil temperature when the sensor has faults.

In some embodiments of the present invention, in the case of a failure of the engine ambient temperature sensor, the step S4 specifically includes:

step S41, calculating the oil temperature by the following formula,

toil-water temperature x correction factor 8 (7)

Wherein, Toil represents the oil temperature value, and the correction coefficient 8 is a calibratable constant.

And step S42, lighting an engine fault lamp and reporting an engine ambient temperature fault code, so that a customer can be reminded to maintain the vehicle.

In some embodiments of the present invention, in the case of a fault of the engine water temperature sensor, the step S4 specifically includes:

step S41', calculating the oil temperature by the following formula,

toil default (8)

Wherein, Toil represents an oil temperature value, and a default value is a calibratable constant.

And step S42', an engine fault lamp is lightened, and an engine water temperature fault code is reported, so that a customer can be reminded to maintain the vehicle.

The engine oil temperature calculating method provided by the embodiment of the invention calculates the engine oil temperature in stages, calculates the engine oil temperature based on different influence factors in different stages by considering variable working conditions in the actual driving of a vehicle, realizes the virtual calculation of the engine oil temperature, achieves the effect of the engine oil temperature being equal to the actual sensor measured temperature through the actual vehicle calibration and test, and can effectively save the cost and accurately obtain the engine oil temperature parameter; and the engine oil temperature value is calculated under the condition of sensor failure, so that the engine oil temperature cannot be obtained when the sensor fails.

Thus, various embodiments of the present disclosure have been described in detail. Some details that are well known in the art have not been described in order to avoid obscuring the concepts of the present disclosure. It will be fully apparent to those skilled in the art from the foregoing description how to practice the presently disclosed embodiments.

Although some specific embodiments of the present disclosure have been described in detail by way of example, it should be understood by those skilled in the art that the foregoing examples are for purposes of illustration only and are not intended to limit the scope of the present disclosure. It will be understood by those skilled in the art that various changes may be made in the above embodiments or equivalents may be substituted for elements thereof without departing from the scope and spirit of the present disclosure. The scope of the present disclosure is defined by the appended claims.