Method and device for determining the urea level during the thawing of urea

Abstract

The application provides a urea liquid level determination method and device in a urea thawing process, the method comprising: for each of at least one preset time period, determining the total heat transferred to the urea in the preset time period based on the total electric heating power, the pre-calibrated heat transfer efficiency and at least one correction factor of the heat transfer efficiency; for each of the preset time period, determining the volume of the urea in the urea tank in the preset time period based on the total heat transferred to the urea in the preset time period, the change of the urea temperature in the urea tank in the preset time period and the heat absorption formula; and determining the liquid level of the urea in the urea tank based on the set of the volume of the urea in the urea tank in all the preset time periods. The urea tank liquid level before thawing is determined, and the ECU misjudgment of the urea liquid level is avoided.

Description

Technical Field

[0001] This invention relates to the field of diesel engine technology, and in particular to a method and apparatus for determining the urea level during the urea thawing process. Background Technology

[0002] The N1 category of China VI regulations requires real-time display of the remaining usable mileage of urea (on the instrument panel). This mileage is calculated and updated based on urea consumption and the remaining urea volume. Furthermore, it requires that urea can be injected within 20 minutes when the ambient temperature is -15°C and the urea is frozen.

[0003] In cold winters, urea freezes and its level cannot be detected (optical sensors require a liquid level to monitor it). Therefore, the electronic control unit (ECU) calculates the remaining mileage by using the difference between the remaining urea volume from the previous driving cycle and the urea volume consumed in the current driving cycle. The problem with this is that after adding urea, the ECU needs to be powered on to read the current level. Otherwise, if the urea freezes again the next day, the ECU will misjudge the current urea volume, resulting in an inaccurate calculation of the remaining mileage. Summary of the Invention

[0004] This invention provides a method and apparatus for determining the urea level during the urea thawing process. This method enables the determination of the urea tank level before thawing is complete, thus avoiding misjudgment of the urea level by the ECU.

[0005] This invention provides a method for determining the urea level during urea thawing, comprising: for each preset time period in at least one preset time period, determining the total heat transferred to the urea within the preset time period based on the total electric heating power, a pre-calibrated heat transfer efficiency, and at least one correction factor for the heat transfer efficiency; for each preset time period, determining the volume of urea in the urea tank within the preset time period based on the total heat transferred to the urea within the preset time period, the change in urea temperature in the urea tank within the preset time period, and the heat absorption formula; and determining the urea level in the urea tank based on the set of urea volumes in the urea tank within all preset time periods.

[0006] In one embodiment, determining the total heat transferred to urea within a preset time period based on the total electric heating power, a pre-calibrated heat transfer efficiency, and at least one correction factor for the heat transfer efficiency includes: determining the total heat transferred to urea within a preset time period based on the product of the total electric heating power, the pre-calibrated heat transfer efficiency, the at least one correction factor, and the duration of the preset time period.

[0007] In one embodiment, the at least one correction factor includes at least one of the following: an ambient temperature correction factor, a vehicle speed correction factor, and a urea tank volume correction factor; the ambient temperature correction factor is directly proportional to the heat transfer efficiency, and the vehicle speed correction factor and the urea tank volume correction factor are inversely proportional to the heat transfer efficiency.

[0008] In one embodiment, determining the volume of urea in the urea tank within a preset time period based on the total heat transferred to urea within a preset time period, the temperature change of urea in the urea tank within the preset time period, and the heat absorption formula includes: determining the mass of urea in the urea tank based on the total heat transferred to urea within the preset time period, the temperature change of urea in the urea tank within the preset time period, the specific heat capacity of urea, and the heat absorption formula; and determining the volume of urea in the urea tank within the preset time period based on the mass of urea in the urea tank.

[0009] In one embodiment, the heat absorption formula is Q = c × m × ΔT, where Q is the total heat transferred to urea within a preset time period, ΔT is the temperature change of urea in the urea tank within the preset time period, c is the specific heat capacity of urea, and m is the mass of urea in the urea tank. Determining the mass of urea in the urea tank based on the total heat transferred to urea within the preset time period, the temperature change of urea in the urea tank within the preset time period, the specific heat capacity of urea, and the heat absorption formula includes: substituting the total heat transferred to urea within the preset time period, the temperature change of urea in the urea tank within the preset time period, and the specific heat capacity of urea into the aforementioned heat absorption formula to determine the mass of urea in the urea tank.

[0010] In one embodiment, determining the urea level in the urea tank based on the set of urea volumes in the urea tank within all preset time periods includes: inputting the set of urea volumes in the urea tank within all preset time periods into a preset filter for filtering, and then determining the urea level in the urea tank within each preset time period based on the filtered urea volume; the filter is used to smooth each volume in the set of urea volumes within all preset time periods, so that the volume in the set changes uniformly with time.

[0011] In one embodiment, the preset filter is an over-PT filter or a two-dimensional filter.

[0012] The present invention also provides a device for determining the urea level during urea thawing, comprising: a first determining module, configured to determine, for each preset time period in at least one preset time period, the total heat transferred to the urea within the preset time period based on the total electric heating power, a pre-calibrated heat transfer efficiency, and at least one correction factor for the heat transfer efficiency; a second determining module, configured to determine, for each preset time period, the volume of urea in the urea tank within the preset time period based on the total heat transferred to the urea within the preset time period, the change in urea temperature in the urea tank within the preset time period, and an endothermic formula; and a third determining module, configured to determine the urea level in the urea tank based on the set of urea volumes in the urea tank within all preset time periods.

[0013] The present invention also provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the steps of the method for determining the urea level during the urea thawing process as described above.

[0014] The present invention also provides a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the method for determining the urea level during the urea thawing process as described in any of the above.

[0015] The present invention provides a method and apparatus for determining the urea level during the urea thawing process. By using heat exchange theory based on the total electric heating power and a pre-calibrated heat transfer efficiency, the mass and volume of urea in the urea tank are determined, thereby enabling the determination of the urea tank level before thawing is complete and avoiding misjudgment of the urea level by the ECU. Furthermore, in determining the total heat transferred to the urea within a preset time period based on the total electric heating power and the pre-calibrated heat transfer efficiency, the influence of the actual environment is considered, and a corresponding correction factor is added to correct the heat transfer efficiency. This facilitates the calculation of the accurate total heat transferred to the urea within the preset time period under different actual vehicle conditions, thus facilitating the accurate determination of the urea tank level before thawing is complete. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0017] Figure 1 This is a flowchart illustrating the method for determining the urea level during the urea thawing process provided by the present invention.

[0018] Figure 2This is a schematic diagram of the framework of the method for determining the urea level during the urea thawing process provided by the present invention.

[0019] Figure 3 This is a schematic diagram of the device for determining the urea level during the urea thawing process provided by the present invention. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0021] To facilitate understanding, the technical terms involved in this invention will first be explained.

[0022] Urea thawing: The process of melting urea from a solid to a liquid by heating with water or electricity;

[0023] Remaining mileage: The number of miles the vehicle can run with the current urea volume.

[0024] It is understandable that in existing technologies, if urea is added after the ECU is powered off the previous day, but the urea freezes the next day, the electronic control unit (ECU) cannot detect the urea level due to the frozen urea. Therefore, it uses the urea level from the previous day (when urea was added) to calculate the remaining mileage, leading to misjudgments of the urea level and remaining mileage. Therefore, this invention provides a method for determining the urea level during the urea thawing process. Based on the total electric heating power and a pre-calibrated heat transfer efficiency, and utilizing heat exchange theory, the method determines the mass and volume of urea in the urea tank, thereby determining the urea tank level before thawing is complete and avoiding ECU misjudgment of the urea level. Furthermore, in determining the total heat transferred to the urea within a preset time period based on the total electric heating power and the pre-calibrated heat transfer efficiency, a correction factor is added to adjust the heat transfer efficiency, taking into account the influence of the actual environment. This facilitates the calculation of the accurate total heat transferred to the urea within the preset time period under different actual vehicle conditions, thus facilitating the accurate determination of the urea tank level before thawing is complete.

[0025] The method and apparatus for determining the urea level during the urea thawing process of the present invention are described below with reference to the accompanying drawings.

[0026] Figure 1This is a flowchart illustrating the method for determining the urea level during the urea thawing process provided by the present invention. It can be understood that the method for determining the urea level during the urea thawing process can be applied to the field of diesel engines and can be executed by a device for determining the urea level during the urea thawing process, such as... Figure 1 As shown, the method includes the following steps:

[0027] Step 110: For each preset time period in at least one preset time period, determine the total heat transferred to urea within the preset time period based on the total electric heating power, the pre-calibrated heat transfer efficiency, and at least one correction factor for the heat transfer efficiency.

[0028] The total electric heating power is determined based on the resistance value of the heating wire of the urea heating tube in the urea tank and the battery voltage.

[0029] The pre-calibrated heat transfer efficiency refers to the heat transfer efficiency of the urea heating element in the urea tank. This pre-calibrated efficiency is determined based on the position of the heating resistance wire within the urea tank and the shape of the urea tank. It is understood that different positions of the heating resistance wire within the urea tank result in different heat transfer efficiencies. Similarly, different shapes of the urea tank also result in different heat transfer efficiencies. For example, because the distance between the urea heating element and the tank wall is more uniform in a spherical urea tank compared to a cylindrical urea tank, the heat transfer efficiency of a spherical urea tank is higher than that of a cylindrical urea tank. Therefore, the corresponding heat transfer efficiency can be set based on the position of the heating resistance wire within the urea tank and the shape of the urea tank.

[0030] In addition, at least one correction factor is a correction factor for the heat transfer efficiency of other factors in the actual scenario of vehicle operation.

[0031] In this system, at least one preset time period has an overlapping time interval between the preceding and following preset time periods. For example, the first preset time period may be heating for 1 to 2 minutes, and the second preset time period may be heating for 1 to 3 minutes. It is understood that because the heating duration of the heating resistance wire varies, the total heat transferred to the urea also varies, and the rate of temperature rise in the urea will also differ. Therefore, to avoid fluctuations in the calculated urea volume under different heating durations, the total heat transferred to the urea can be recalculated periodically, so that the urea volume can be determined subsequently based on the calculated total heat transferred to the urea.

[0032] Step 120: For each preset time period, based on the total heat transferred to urea within the preset time period, the change in urea temperature in the urea tank within the preset time period, and the heat absorption formula, determine the volume of urea in the urea tank within the preset time period.

[0033] In one embodiment, step 120 involves determining the volume of urea in the urea tank within a preset time period based on the total heat transferred to urea within the preset time period, the temperature change of urea in the urea tank within the preset time period, and the heat absorption formula. This includes: determining the mass of urea in the urea tank based on the total heat transferred to urea within the preset time period, the temperature change of urea in the urea tank within the preset time period, the specific heat capacity of urea, and the heat absorption formula; and determining the volume of urea in the urea tank within the preset time period based on the mass of urea in the urea tank.

[0034] The heat absorption formula is Q = c × m × ΔT, where Q is the total heat transferred to urea within a preset time period, ΔT is the temperature change of urea in the urea tank within the preset time period, c is the specific heat capacity of urea, and m is the mass of urea in the urea tank.

[0035] In one embodiment, determining the mass of urea in the urea tank based on the total heat transferred to urea within a preset time period, the change in urea temperature in the urea tank within the preset time period, the specific heat capacity of urea, and the heat absorption formula includes: substituting the total heat transferred to urea within the preset time period, the change in urea temperature in the urea tank within the preset time period, and the specific heat capacity of urea into the aforementioned heat absorption formula to determine the mass of urea in the urea tank.

[0036] It is understandable that, after determining the mass of urea in the urea tank, the volume of urea in the tank can be determined by combining the density of urea.

[0037] Step 130: Determine the urea level in the urea tank based on the set of urea volumes in the urea tank during all preset time periods.

[0038] Under normal circumstances, the urea level in the urea tank can be determined directly based on the volume of urea in the tank within each preset time period. However, to avoid large jumps in the urea level displayed to the user during the heating process across different preset time periods, the calculated volume of urea in the tank for each time period is compared with the volume of urea in the tank for the previous preset time period and then filtered by a preset filter. This filter smooths the volumes in the set of urea volumes across all preset time periods, ensuring that the volumes in the set change at a uniform rate over time.

[0039] Therefore, in one embodiment, the set of urea volumes in the urea tank within all preset time periods can be input into a preset filter for filtering. Based on the filtered urea volume within each preset time period, the urea level in the urea tank within each preset time period can be determined. The filter is used to smooth each volume in the set of urea volumes within all preset time periods, so that the volume in the set of volumes changes uniformly with time.

[0040] The preset filter is either an over-PT filter or a two-dimensional filter.

[0041] The method for determining the urea level during urea thawing provided by this invention determines the mass and volume of urea in the urea tank based on the total electric heating power and a pre-calibrated heat transfer efficiency, using heat exchange theory. This allows for the determination of the urea tank level before thawing is complete, avoiding misjudgment of the urea level by the ECU. Furthermore, in determining the total heat transferred to the urea within a preset time period based on the total electric heating power and the pre-calibrated heat transfer efficiency, the method considers the influence of the actual environment and adds a corresponding correction factor to adjust the heat transfer efficiency. This facilitates the calculation of the accurate total heat transferred to the urea within the preset time period under different actual vehicle conditions, thus enabling accurate determination of the urea tank level before thawing is complete.

[0042] In one embodiment, determining the total heat transferred to urea within a preset time period for each preset time period in at least one preset time period, based on the total electric heating power, a pre-calibrated heat transfer efficiency, and at least one correction factor for the heat transfer efficiency, includes: determining the total heat transferred to urea within a preset time period based on the product of the total electric heating power, the pre-calibrated heat transfer efficiency, the at least one correction factor, and the duration of the preset time period.

[0043] In one embodiment, the at least one correction factor includes at least one of the following: an ambient temperature correction factor, a vehicle speed correction factor, and a urea tank volume correction factor; the ambient temperature correction factor is directly proportional to the heat transfer efficiency, and the vehicle speed correction factor and the urea tank volume correction factor are inversely proportional to the heat transfer efficiency.

[0044] Each correction factor can be obtained through pre-calibration. It is understood that since the urea tank is typically exposed to the outside of the vehicle, higher ambient temperatures result in higher heat transfer efficiency; therefore, the ambient temperature correction factor is directly proportional to heat transfer efficiency. Similarly, higher vehicle speeds lead to higher wind speeds and lower heat transfer efficiency; larger urea tank volumes also result in lower heat transfer efficiency. Therefore, both the vehicle speed correction factor and the urea tank volume correction factor are inversely proportional to heat transfer efficiency.

[0045] It is understood that this is merely an illustrative example of one method for determining the total heat transferred to urea within a preset time period. In other embodiments, at least one correction factor can be added to the heat transfer efficiency and then multiplied by the total electric heating power and the duration of the preset time period to determine the total heat transferred to urea within the preset time period.

[0046] Figure 2 This is a schematic diagram illustrating the framework of the method for determining the urea level during the urea thawing process provided by the present invention. Figure 2As shown, firstly, the total electric heating power is determined by the resistance value of the heating wire of the urea heating tube in the urea tank and the battery voltage. Then, the total heat transferred to the urea within at least one preset time period is determined by combining the heat transfer efficiency and at least one correction factor. Then, based on the heat absorption formula and the total heat, the mass, volume, and liquid level of the urea are determined sequentially.

[0047] The device for determining the urea level during the urea thawing process provided by the present invention will be described below.

[0048] Figure 3 This is a schematic diagram of the device for determining the urea level during the urea thawing process provided by the present invention, as shown below. Figure 3 As shown, the device for determining the urea liquid level during the urea thawing process provided by the present invention includes: a first determining module 310, which determines the total heat transferred to the urea within each preset time period based on the total electric heating power, the pre-calibrated heat transfer efficiency, and at least one correction factor for the heat transfer efficiency for each preset time period in at least one preset time period.

[0049] The second determining module 320 is used to determine the volume of urea in the urea tank within a preset time period based on the total heat transferred to urea within the preset time period, the change in urea temperature in the urea tank within the preset time period, and the heat absorption formula for each preset time period.

[0050] The third determining module 330 is used to determine the urea level in the urea tank based on the set of urea volumes in the urea tank within all preset time periods.

[0051] The urea level determination device provided by this invention determines the urea level during urea thawing by using heat exchange theory based on the total electric heating power and a pre-calibrated heat transfer efficiency. This allows for the determination of the urea level in the tank before thawing is complete, avoiding misjudgment of the urea level by the ECU. Furthermore, in determining the total heat transferred to the urea within a preset time period based on the total electric heating power and the pre-calibrated heat transfer efficiency, a correction factor is added to adjust the heat transfer efficiency, taking into account the influence of the actual environment. This facilitates the calculation of the accurate total heat transferred to the urea within the preset time period under different actual vehicle conditions, thus enabling accurate determination of the urea level in the tank before thawing is complete.

[0052] In one embodiment, a computer device is provided, the computer device including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the following steps corresponding to a method for determining the urea level during urea thawing: for each preset time period in at least one preset time period, determining the total heat transferred to the urea within the preset time period based on the total electric heating power, a pre-calibrated heat transfer efficiency, and at least one correction factor for the heat transfer efficiency; for each preset time period, determining the volume of urea in the urea tank within the preset time period based on the total heat transferred to the urea within the preset time period, the change in urea temperature in the urea tank within the preset time period, and the heat absorption formula; and determining the urea level in the urea tank based on the set of urea volumes in the urea tank within all preset time periods.

[0053] On the other hand, the present invention also provides a computer program product, the computer program product comprising a computer program stored on a non-transitory computer-readable storage medium, the computer program comprising program instructions, wherein when the program instructions are executed by a computer, the computer is able to execute the method for determining the urea level during the urea thawing process provided by the present invention, the method comprising: for each preset time period in at least one preset time period, determining the total heat transferred to the urea within the preset time period based on the total electric heating power, a pre-calibrated heat transfer efficiency, and at least one correction factor of the heat transfer efficiency; for each preset time period, determining the volume of urea in the urea tank within the preset time period based on the total heat transferred to the urea within the preset time period, the change in urea temperature in the urea tank within the preset time period, and the heat absorption formula; and determining the urea level in the urea tank based on the set of urea volumes in the urea tank within all preset time periods.

[0054] In another aspect, the present invention also provides a non-transitory computer-readable storage medium having a computer program stored thereon. When executed by a processor, the computer program implements a method for determining the urea level during the urea thawing process provided by the present invention. The method includes: for each of at least one preset time period, determining the total heat transferred to the urea within the preset time period based on the total electric heating power, a pre-calibrated heat transfer efficiency, and at least one correction factor for the heat transfer efficiency; for each preset time period, determining the volume of urea in the urea tank within the preset time period based on the total heat transferred to the urea within the preset time period, the change in urea temperature in the urea tank within the preset time period, and an endothermic formula; and determining the urea level in the urea tank based on the set of urea volumes in the urea tank within all preset time periods.

[0055] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without any creative effort.

[0056] Through the above description of the embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus necessary general-purpose hardware platforms, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solutions, in essence or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods described in the various embodiments or some parts of the embodiments.

[0057] It is understood that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for determining the urea level during urea thawing, characterized in that, include: For each preset time period in at least one preset time period, the total heat transferred to urea within the preset time period is determined based on the total electric heating power, the pre-calibrated heat transfer efficiency, at least one correction factor for the heat transfer efficiency, and the duration of the preset time period. For each preset time period, the volume of urea in the urea tank is determined based on the total heat transferred to urea within the preset time period, the change in urea temperature in the urea tank within the preset time period, the heat absorption formula, the specific heat capacity of urea, and the density of urea. Based on the set of urea volumes in the urea tank within all preset time periods, the urea level in the urea tank is determined after filtering. The at least one correction factor includes at least one of the following: ambient temperature correction factor, vehicle speed correction factor, and urea tank volume correction factor; the ambient temperature correction factor is directly proportional to the heat transfer efficiency, and the vehicle speed correction factor and the urea tank volume correction factor are both inversely proportional to the heat transfer efficiency; the pre-calibrated heat transfer efficiency is set based on the position of the heating resistance wire in the urea tank and the shape of the urea tank.

2. The method for determining the urea level during urea thawing according to claim 1, characterized in that, The determination of the volume of urea in the urea tank within the preset time period, based on the total heat transferred to urea within the preset time period, the temperature change of urea in the urea tank within the preset time period, the heat absorption formula, the specific heat capacity of urea, and the density of urea, includes: The mass of urea in the urea tank is determined based on the total heat transferred to urea within a preset time period, the temperature change of urea in the urea tank within the preset time period, the specific heat capacity of urea, and the heat absorption formula. Based on the mass and density of urea in the urea tank, the volume of urea in the urea tank within a preset time period is determined.

3. The method for determining the urea level during urea thawing according to claim 2, characterized in that, The heat absorption formula is Q = c × m × ΔT, where Q is the total heat transferred to urea within a preset time period, ΔT is the change in urea temperature in the urea tank within the preset time period, c is the specific heat capacity of urea, and m is the mass of urea in the urea tank. The determination of the mass of urea in the urea tank based on the total heat transferred to urea within a preset time period, the temperature change of urea in the urea tank within the preset time period, the specific heat capacity of urea, and the heat absorption formula includes: Substituting the total heat transferred to urea within a preset time period, the change in urea temperature in the urea tank within the preset time period, and the specific heat capacity of urea into the above heat absorption formula, the mass of urea in the urea tank is determined.

4. The method for determining the urea level during urea thawing according to claim 1, characterized in that, The determination of the urea level in the urea tank based on the set of urea volumes in all preset time periods, after filtering, includes: The set of urea volumes in the urea tank within all preset time periods is input into a preset filter for filtering. Based on the filtered urea volume within each preset time period, the urea level in the urea tank within each preset time period is determined. The filter is used to smooth each volume in the set of urea volumes within all preset time periods, so that the volume in the set changes uniformly with time.

5. The method for determining the urea level during urea thawing according to claim 4, characterized in that, The preset filter is a PT filter or a two-dimensional filter.

6. A device for determining the urea level during urea thawing, characterized in that, include: The first determining module is used to determine the total heat transferred to urea within a preset time period for each preset time period in at least one preset time period, based on the total electric heating power, the pre-calibrated heat transfer efficiency, at least one correction factor for the heat transfer efficiency, and the duration of the preset time period. The second determining module is used to determine the volume of urea in the urea tank for each preset time period based on the total heat transferred to urea within the preset time period, the change in urea temperature in the urea tank within the preset time period, the heat absorption formula, the specific heat capacity of urea, and the density of urea. The third determining module is used to determine the urea level in the urea tank based on the set of urea volumes in the urea tank within all preset time periods, after filtering by a filter. The at least one correction factor includes at least one of the following: ambient temperature correction factor, vehicle speed correction factor, and urea tank volume correction factor; the ambient temperature correction factor is directly proportional to the heat transfer efficiency, and the vehicle speed correction factor and the urea tank volume correction factor are both inversely proportional to the heat transfer efficiency; the pre-calibrated heat transfer efficiency is set based on the position of the heating resistance wire in the urea tank and the shape of the urea tank.

7. A computer device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the program, it implements the steps of the method for determining the urea level during the urea thawing process as described in any one of claims 1 to 5.

8. A non-transitory computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the steps of the method for determining the urea level during the urea thawing process as described in any one of claims 1 to 5.

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