A urea tank liquid level height monitoring system and testing method

Abstract

The application discloses a urea tank liquid level height monitoring system and a testing method, two sets of sensing systems are installed in the urea tank to read and store liquid level height data of left and right sides of the urea tank in real time; by processing and analyzing the liquid level height data, the current urea tank state can be determined according to the variance of the liquid level height series difference value, such as liquid adding, normal use, abnormal liquid leakage, shaking and serious shaking; the liquid level height data is processed according to the proposed algorithm to obtain the current liquid level height result. The application can reduce the measurement error and still obtain a relatively accurate urea tank liquid level height under severe shaking; the application can determine various states of the urea tank, and only alarms in the case of abnormal liquid leakage, thereby reducing the triggering of the alarm signal under the working conditions such as uphill and downhill, and ensuring the normal driving of the vehicle.

Description

Technical Field

[0001] This invention relates to the field of engine aftertreatment systems, and more particularly to a urea tank liquid level monitoring system and testing method. Background Technology

[0002] Urea tanks have become standard equipment in automobiles, providing urea solution for the SCR system. To ensure the proper functioning of the SCR system, existing urea tanks are equipped with a urea level sensor system to monitor the urea level in real time and issue an alarm signal when the level falls below a threshold, reminding the driver to add urea solution.

[0003] However, existing urea level sensing systems have some problems. When the vehicle is shifting gears, the solution in the urea tank is agitated, resulting in a significant difference between the measured and actual levels, leading to low measurement accuracy. This agitation is particularly pronounced when the vehicle is going uphill or downhill, potentially causing the level at the sensor to fall below the threshold, triggering false alarms and affecting normal vehicle operation. Furthermore, existing sensing systems lack monitoring and alarm functions for abnormal urea tank leaks, resulting in unnecessary losses of the urea solution. Summary of the Invention

[0004] The purpose of this invention is to provide a urea tank liquid level monitoring system and testing method. This method adds a liquid level sensing system to the original system. By reading and analyzing the liquid level data in real time, the actual liquid level in the urea tank can be accurately obtained, and the current state of the urea tank can be determined. An alarm signal is issued only in the case of abnormal leakage, thereby ensuring the normal operation of the vehicle.

[0005] To solve the above problems, the present invention proposes a urea tank liquid level monitoring system and testing method, wherein a liquid level sensor 2, a sliding rod 3 and a float 4 are installed on both the left and right sides of the urea tank 1.

[0006] Preferably, the urea tank liquid level monitoring system and testing method include the following steps: 1) Calculate the liquid level height based on the resistance signals from the left and right sensors respectively. hL k and hR k The liquid level data is stored every 30 seconds; 2) After each data storage, read back 5 liquid level data points to form the left-hand liquid level column S6. hL k ) and the right-hand liquid level column S6 ( hR k ); 3) Calculate the absolute value of the difference in liquid level height on both sides. ∆h k = | hL k - hR k | and determine ∆h k Size; 4) If ∆h k If the value is less than 2, the average of the liquid levels on the left and right sides will be used as the actual liquid level height. h 0 = ( hL k + hR k ) / 2; 5) If ∆h k >2, then calculate the sequence S6( hL k S6 hR k The forward differences between adjacent data in the sequence S5 are used to form the difference sequence. xhL k ) and S5 ( xhR k ), calculate the variance D( ) of the two difference series respectively. xhL k ) and D( xhR k ), calculate the mean D of the two. xh k And determine its size; 6) If D( xh k If ) < 5, then calculate the sequence S6 of the liquid level height on the left side. hL k ) and difference sequence S5 ( xhL k The tail-cutting mean JhL k and JxhL k And calculate the liquid level height sequence S6 on the right side. hR k ) and S5 ( xhR k The tail-cutting mean ​ k and ​ k Therefore, the actual liquid level height can be calculated. h 0 = ( ​ k + ​ k ) / twenty four * [(​ k + ​ k ) / 2]; 7) If D( ​ k If the value is greater than 5, then continue reading several sets of data forward and record the number of forward reads. n Until the variance of the sequence is less than 5, a stable sequence S6 is obtained. ​ k-n ) and S6 ( ​ k-n ), and calculate the tail-cut mean of the stable series. ​ k-n , ​ k-n and ​ k-n , ​ k-n Therefore, the actual liquid level height can be calculated. h 0 = ( ​ k-n + ​ k-n ) / 2 – (4 + n ) *[( ​ k-n + ​ k-n ) / 2).

[0007] Preferably, the urea tank liquid level monitoring system and testing method can determine the liquid addition status: if D( ​ k )<1 and the difference ​ k If the value is less than 0, it is considered to be in a stable liquid addition state.

[0008] Preferably, the urea tank liquid level monitoring system and testing method can determine the normal operating state: if D( ​ k )<1 and 0< ​ k If the value is less than 2, it is considered to be in normal working condition.

[0009] Preferably, the urea tank liquid level monitoring system and testing method are characterized in that they can determine abnormal leakage conditions: if D( ​ k )<1 and the difference ​ k If the value is greater than 2, it is considered to be in an abnormal leakage state, and an alarm will be triggered.

[0010] Preferably, the urea tank liquid level monitoring system and testing method are characterized in that they can determine the swaying state: if 1 <D(​ k If D( ) < 5, then the urea tank is considered to be in a shaking state; when D( ​ k When the value exceeds 5, it is considered that the urea tank is in a state of violent shaking, and an orange warning signal is sent to the vehicle control platform to remind the user to drive smoothly.

[0011] Preferably, the urea tank liquid level monitoring system and testing method are characterized in that all judgment criteria are set based on laboratory measurement results.

[0012] The technical solution provided in this invention application has the following advantages compared with the prior art: Using two sets of liquid level sensors allows for more accurate measurement of the liquid level. Even when the urea tank is swaying, relatively accurate liquid level results can still be obtained through data extraction and processing. By analyzing the liquid level data, the current state of the urea tank can be determined, and alarm processing will only be triggered in case of abnormal leakage, reducing the triggering of alarm signals under conditions such as uphill and downhill driving, and avoiding interference with the normal operation of the vehicle. Attached Figure Description

[0013] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0014] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0015] ​ This is a schematic diagram of a urea tank liquid level monitoring system and testing method according to an embodiment of the present invention; ​ This is a flowchart of a urea tank liquid level monitoring system and testing method according to an embodiment of the present invention; Reference numerals: 1-Urea tank, 2-Level sensor, 3-Sliding rod, 4-Float. Detailed Implementation

[0016] To provide a clearer understanding of the technical features, objectives, and effects of the present invention, specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0017] To implement the urea tank liquid level monitoring system and testing method described in this invention, a liquid level sensor 2, a slide bar 3, and a float 4 are installed on both the left and right sides of the urea tank 1.

[0018] In one embodiment, the urea tank liquid level monitoring system and testing method calculate the liquid level height based on the resistance signals from the left and right sensors. ​ k and ​ k The liquid level data is stored every 30 seconds.

[0019] Each time data is stored, five more liquid level data points are read from the previous sequence to form a number, i.e.: Left side liquid level column S6 ( ​ k )Include ​ k-5 , ​ k-4 , ​ k-3 , ​ k-2 , ​ k-1 and ​ k ; Right side liquid level column S6 ( ​ k )Include ​ k-5 , ​ k-4 , ​ k-3 , ​ k-2 , ​ k-1 and ​ k .

[0020] Calculate the absolute value of the difference in liquid level between the two sides. ∆h k = | ​ k - ​ k | and determine ∆h k Size.

[0021] if ∆h k If the value is less than 2, then the average of the liquid levels on both sides is taken as the actual liquid level height. h 0 = ( ​ k + ​ k ) / 2.

[0022] if ∆h k >2, then calculate the sequence S6( ​k The forward difference between adjacent data in ) ​ k = ​ k-1 - ​ k ; 5 differences ​ k-4 , ​ k-3 , ​ k-2 , ​ k-1 , ​ k Form a sequence S5 ( ​ k ), calculate the difference sequence S5( ​ k The variance D( ​ k ); For the liquid level height sequence S6 on the right side ( ​ k The same process is applied to obtain the liquid level difference sequence S5 on the right. ​ k The variance D( ​ k ); Calculate D( ​ k ) and D( ​ k The mean of ), i.e., D( ​ k ) = [D( ​ k )+D( ​ k )] / 2, and determine D( ​ k The size of ).

[0023] If D( ​ k If ) < 5, then in the left-side liquid level height sequence S6 ( ​ k ) and difference sequence S5 ( ​ k In the original text, the maximum and minimum values ​​are removed, and the average of the remaining data is calculated to obtain the tail-cut mean. ​ k and ​ k ; Calculate the sequence S6 using the same method. ​ k ) and S5 (​ k The tail-cutting mean ​ k and ​ k ; The actual liquid level height is calculated based on the average of several cut-off values, i.e. h 0 = ( ​ k + ​ k ) / twenty four * [( ​ k + ​ k ) / 2).

[0024] If D( ​ k If the result is greater than 5, continue reading forward several sets of numbers, and record the number of forward reads. n It should be noted that the difference between each set of numbers is only one value, namely, the difference between set S6 and S7. ​ k-1 The data contained is ​ k-6 , ​ k-5 , ​ k-4 , ​ k-3 , ​ k-2 and ​ k-1 Sequence S6( ​ k-2 The data contained is ​ k-7 , ​ k-6 , ​ k-5 , ​ k-4 , ​ k-3 and ​ k-2 ; While reading the sequence forward, calculate the corresponding difference sequence and its variance until D( ​ k-n If the value is less than 5, stop reading and consider the resulting sequence S6( ​ k-n ) and S6 ( ​ k-n It is in a relatively stable state; Calculate the tail-cut mean of the steady-state series of liquid levels. ​ k-n , ​k-n Sum and difference tail-cutting mean ​ k-n , ​ k-n ; The actual liquid level height is calculated based on the average value of the cut-off tail and the number of reads. h 0 = ( ​ k-n + ​ k-n ) / 2 – (4+ n ) * [( ​ k-n + ​ k-n ) / 2).

[0025] In one embodiment, if D( ​ k )<1 and the difference ​ k If D( < 0, the urea tank is considered to be in a stable liquid addition state; if D( ​ k )<1 and 0< ​ k If the value is less than 2, the urea tank is considered to be in normal working condition; in this case, no signal is sent to the vehicle control platform.

[0026] In one embodiment, if D( ​ k )<1 and the difference ​ k If the value is >2, it is considered that the urea tank is in an abnormal leakage state, and a red alarm signal is sent to the vehicle control platform to remind the user to stop and check the urea tank.

[0027] In one embodiment, if 1 <D( ​ k If D( ) < 5, then the urea tank is considered to be in a shaking state, and no signal is sent to the vehicle control platform. ​ k When the value exceeds 5, it is considered that the urea tank is in a state of violent shaking, and an orange warning signal is sent to the vehicle control platform to remind the user to drive smoothly.

[0028] It is understood that the above embodiments only illustrate preferred embodiments of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can freely combine the above technical features without departing from the concept of the present invention, and can also make several modifications and improvements, all of which fall within the protection scope of the present invention. Therefore, all equivalent transformations and modifications made with respect to the scope of the claims of the present invention should fall within the scope of the claims of the present invention.

Claims

1. A method for monitoring the liquid level in a urea tank, characterized in that, A liquid level sensor (2), a slide bar (3), and a float (4) are installed on both the left and right sides of the urea tank (1); the method includes the following steps: 1) Calculate the liquid level height based on the resistance signals from the left and right sensors respectively. and The liquid level data is stored every 30 seconds. 2) Each time data is stored, read back 5 liquid level data points to form the liquid level column on the left. and the liquid level column on the right ; 3) Calculate the absolute value of the difference in liquid level height on both sides. and determine Size; 4) If Then the average of the liquid levels on the left and right sides is taken as the actual liquid level height. ; 5) If Then calculate the sequence respectively. , The forward differences between adjacent data points form a difference sequence. and Calculate the variance of the two difference series respectively. and Calculate the mean of the two. And determine its size; 6) If Then calculate the sequence of liquid level heights on the left. Sum and difference sequence tail cutting mean and And calculate the sequence of liquid level heights on the right. and tail cutting mean and Therefore, the actual liquid level height can be calculated. ; 7) If Then continue reading several sets of data forward, recording the number of forward reads n, until the variance of the sequence is less than 5, thus obtaining a stable sequence. and And calculate the tail-cut mean of the stable series. , and , Therefore, the actual liquid level height can be calculated. .

2. The method for monitoring the liquid level in a urea tank according to claim 1, characterized in that, Determine the liquid addition status: If And the difference If the liquid is added, it is considered to be in a stable liquid addition state.

3. The method for monitoring the liquid level in a urea tank according to claim 1, characterized in that, Determining normal usage status: If and If so, it is considered to be in normal use condition.

4. The method for monitoring the liquid level in a urea tank according to claim 1, characterized in that, Determine abnormal leakage status: If And the difference If the leakage is detected, it is considered to be in an abnormal leakage state, and an alarm will be triggered.

5. The method for monitoring the liquid level in a urea tank according to claim 1, characterized in that, Determine the fluctuation state: If If the urea tank is shaking, it is considered to be in a shaking state; when At that time, it is assumed that the urea tank is in a state of violent shaking, and an orange warning signal is sent to the vehicle control platform to remind the user to drive smoothly.

6. The method for monitoring the liquid level in a urea tank according to claim 1, characterized in that, All judgment criteria were set based on laboratory measurement results.

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