Self-learning algorithm for fluid level sensor diagnostics

Abstract

A fluid storage system includes a fluid tank with a fluid level sensor, and an injector for delivering fluid from the fluid tank in controlled amounts. A method for providing fluid level sensor diagnostics for a wide range of tank shapes, tank sizes, and fluid sensor types includes learning sensor resolution, fluid tank geometry, and fluid tank volume based on outputs from the fluid level sensor and estimated amounts of fluid delivered from the fluid tank.

Description

Attorney Docket No. CMI002-00102 / 23-0079-SRC SSELF-LEARNING ALGORITHM FOR FLUID LEVEL SENSOR DIAGNOSTICS Cross-reference to related application:

[0001] The present application claims the benefit of the filing date of, and priority to, U.S. Provisional Patent App. No. 63 / 535,807 filed on August 31, 2023, which is incorporated herein by reference. TECHNICAL FIELD

[0002] The present disclosure relates generally to fluid level sensors, and, more particularly, but not exclusively, to self-learning algorithms for fluid level sensor diagnostics for fluid storage systems used for internal combustion engines and vehicles. BACKGROUND

[0003] Fluid storage systems for engines and vehicles can be provided with a wide variety of fluid level sensor types, storage tank sizes, and storage tank geometries. Diagnostics required for engines and vehicles can involve determining whether the fluid level sensor is malfunctioning or otherwise providing improper readings. Existing techniques for fluid level sensor diagnostics may require limiting the type of fluid level sensor that can be used, limiting the fluid tank size, and / or limiting the fluid tank geometry. Existing fluid level sensor diagnostics may also generate false sensor fault determinations, allow for detection of only certain types of sensor faults, and / or may involve unique software and calibration builds for each unique fluid tank configuration. While offering some benefits, existing approaches suffer from a number of challenges, drawbacks, shortcomings, and unsolved problems. Therefore, there remains a significant need for the apparatuses, methods, and systems disclosed herein. Page 1 of 20 133769351v1Attorney Docket No. CMI002-00102 / 23-0079-SRC DISCLOSURE OF EXAMPLE EMBODIMENTS

[0004] For the purposes of clearly, concisely, and exactly describing example embodiments of the present disclosure, the manner, and process of making and using the same, and to enable the practice, making and use of the same, reference will now be made to certain example embodiments, including those illustrated in the figures, and specific language will be used to describe the same. It shall nevertheless be understood that no limitation of the scope of the invention is thereby created, and that the invention includes and protects such alterations, modifications, and further applications of the example embodiments as would occur to one skilled in the art. SUMMARY

[0005] A fluid storage system is disclosed that includes a fluid tank with a fluid level sensor, and an injector for delivering fluid from the fluid tank in controlled amounts. Fluid level sensor diagnostics are provided for a wide range of tank shapes, tank sizes, and fluid sensor types that include learning sensor resolution, fluid tank geometry, and fluid tank volume based on outputs from the fluid level sensor and estimated amounts of fluid delivered from the fluid tank.

[0006] One embodiment is a unique process or processes for fluid level sensor self-learning for sensor diagnostic purposes. In an embodiment, fluid level sensor rationality is determined by learning sensor resolution, fluid tank geometry, and fluid tank volume and making a sensor diagnostic determination based on the same. A further embodiment is a unique system for self- learning fluid level sensor rationality for a fluid storage tank.

[0007] Further embodiments, forms, objects, features, advantages, aspects, and benefits shall become apparent from the following description and drawings. Page 2 of 20 133769351v1Attorney Docket No. CMI002-00102 / 23-0079-SRC BRIEF DESCRIPTION OF THE DRAWINGS

[0008] FIG. 1 is a schematic illustration of certain aspects of an example fluid storage system.

[0009] FIG. 2 is a flow diagram depicting certain aspects of an example self-learning procedure for diagnostics of a fluid level sensor of a fluid storage system.

[0010] FIG. 3 is a flow diagram depicting certain aspects of a sensor resolution learning circuit of the self-learning procedure for fluid level sensor diagnostics of FIG.2.

[0011] FIG.4 is a flow diagram depicting certain aspects of a tank geometry learning circuit of the self-learning procedure for fluid level sensor diagnostics of FIG.2.

[0012] FIG.5 is a flow diagram depicting certain aspects of a tank volume learning circuit of the self-learning procedure for fluid level sensor diagnostics of FIG.2. Page 3 of 20 133769351v1Attorney Docket No. CMI002-00102 / 23-0079-SRC DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS

[0013] With reference to FIG.1, there is illustrated an example system 100 for operating and managing a fluid storage system 120 for a vehicle 102. In FIG. 1, system 100 includes an internal combustion engine 104 that operates with fuel to produce exhaust gases that are treated in aftertreatment system 106 of vehicle 102. Fluid storage system 120 includes at least one of a first tank 122, such as for storage of fuel, and a second tank 124, such as for storage of dosing fluid. A first fluid, such as fuel from first tank 122, can be supplied to engine 104 via a fuel injector 108. A second fluid, such as diesel exhaust fluid (DEF) or other dosing fluid from second tank 144, can be supplied to aftertreatment system via a doser injector 110. First and second tanks 122, 124 each include respective ones of a fluid level sensor 126, 128 that is operable to measure the fluid level therein.

[0014] In some embodiments, system 100 includes an electronic control unit (ECU) 130 connected to one or both of fluid level sensors 126, 128 and to one or both fuel injector 108 and doser injector 110. ECU 130 is also in operative communication with and configured to receive fluid level readings from one or both of fluid level sensors 126, 128. ECU 130 is further in operative communication with and configured to control operation of fuel injector(s) 108 to inject fuel into combustion cylinders of engine 104 from first tank 122 and / or to control operation of dosing injector 110 to dose fluid from second tank 124 into aftertreatment system 106. ECU 130 is further in operative communication with and configured to determine and store an amount of fluid injected by fuel injector(s) 108 from first tank 122 and / or an amount of dosing fluid injected by dosing injector 110 from second tank 124.

[0015] ECU 130 is an example of a component of an electronic control system (ECS) configured and operable to execute operating logic that defines various control, diagnostic, management, and / or regulation functions. For example, the non-transitory memory medium may be configured with instructions executable by the processor to perform a number of acts, evaluations, or operations including those described herein. The operating logic of ECU 130 or other ECS components may be in the form of dedicated hardware, such as a hardwired state machine, analog calculating machine, programming instructions, and / or a different form as would occur to those skilled in the art.

[0016] While ECU 130 is depicted as single unit in the illustrated example, it shall be appreciated that one or more processor, one or more non-transitory memory medium, and related Page 4 of 20 133769351v1Attorney Docket No. CMI002-00102 / 23-0079-SRC components may be provided as or distributed across or among multiple units or physical packages. For example, one or more processors, such as programmable microprocessors or microcontrollers of a solid-state, integrated circuit type which may be provided in one or more control units and can be implemented in any of a number of ways that combine or distribute the control function across one or more control units in various manners. Other components or subsystems of ECU 130 and / or its associated ECS may also be so configured or provided.

[0017] With reference to FIG. 2, there is illustrated an example procedure 200 which may be implemented and performed, in whole or in part, in connection with a system such as system 100 and / or ECU 130. Procedure 200 is one example of a method according to the present disclosure for performing a diagnostic, such as a rationality check or malfunction indication, for a fluid level sensor 202, such as one or both of fluid level sensors 126, 128 for a fluid tank 206, such as one or both of first and second fluid tanks 122, 124.

[0018] The schematic flow descriptions which follow provide an illustrative embodiment of performing procedures for diagnosing fluid level sensor 202. Operations illustrated are understood to be exemplary only, and operations may be combined or divided, and added or removed, as well as re-ordered in whole or part, unless stated explicitly to the contrary herein. Certain operations illustrated may be implemented by a computer, such as ECU 130, executing a computer program product on a non-transitory computer readable medium, where the computer program product comprises instructions causing the computer to execute one or more of the operations, or to issue commands to other devices to execute one or more of the operations.

[0019] Procedure 200 includes an operation 208 for receiving inputs that are used to learn attributes of the fluid tank 206 that are used for diagnostics of fluid level sensor 202. The inputs at operation 208 include fluid level measurements output from fluid level sensor 202 and an estimated fluid consumption from tracking the amount of fluid injected by an injector 204, such as fluid injector 108 or doser injector 110, from fluid tank 206.

[0020] From operation 208, procedure 200 continues along parallel paths. A first path includes a default calibration circuit operation 210 that provides a default calibration for performance of the fluid level sensor diagnostics. In an embodiment, the default calibration is a worst case scenario for the fluid level sensor resolution, tank volume, and tank geometry combination. In an embodiment, about 10 to 20 shifts or cycles of operating vehicle 100 are Page 5 of 20 133769351v1Attorney Docket No. CMI002-00102 / 23-0079-SRC contemplated in order to provide sufficient learning to update the diagnostic based on learned conditions rather than default worst case conditions, as discussed further below.

[0021] The second path for procedure 200 that parallels the default calibration circuit operation 210 includes an operation 212 for processing the inputs from operation 208 and an operation 214 that involves an adaptation circuit. Operation 212 may include, for example, filtering readings from fluid level sensor 202 and / or estimates of fluid consumption from injections or doses provided by injector 204. Operation 212 may also include correcting readings from fluid level sensor 202 and / or estimates of fluid consumption from injections or doses provided by injector 204. Operation 212 may also include eliminating outliers from the inputs or readings from fluid level sensor 202 and / or estimates of fluid consumption from injections or doses provided by injector 204 received from operation 208.

[0022] Once the processing of the input data is complete at operation 212, procedure 200 continues operation using the input data at operation 214 which includes a data adaptation circuit. The adaptation circuit at operation 214 includes a learning circuit operation 216, a learning confidence estimator operation 218, and a diagnostic margin circuit operation 220. Learning circuit operation 216 includes a sensor resolution learning circuit operation 222, a fluid tank geometry learning circuit operation 224, and a fluid tank volume learning circuit operation 226, embodiments of which are discussed further below with reference to FIGs.3-5.

[0023] Operation 218 applies a learning confidence to quantify an uncertainty on the learned variables from learning circuit 216. In an embodiment, operation 218 applies bounds on the estimates of the learned sensor resolution, the learned tank geometry, and the learned tank volume. Operation 220 applied a diagnostic margin, such as a margin of error, to the learned variables based on the confidence estimate. In an embodiment, the margin for diagnosing a fault condition is lowered as learning about the geometry of the fuel tank 206 increases.

[0024] Outputs from default calibration circuit operation 210 and adaptation circuit operation 214 are processed at an output operation 228. Output operation 228 provides a diagnostic output for the fluid level sensor 202 based on the default calibration circuit operation 210 and the adaptation circuit operation 214. Output operation 228 may include applying a diagnostic fault threshold 230 and / or a diagnostic pass threshold 232 to the fluid level sensor diagnostic. The fluid level sensor diagnostic output may include, for example, a sensor rationality check, a sensor Page 6 of 20 133769351v1Attorney Docket No. CMI002-00102 / 23-0079-SRC stuck indication, a diagnosis of high and / or low fluid level readings for sensor high and low rationality checks, and / or a sensor malfunction indication.

[0025] Alternatively or additionally, the fluid level sensor diagnostic outputs at operation 228 may include performing a sensor failure verification operation, and determine the sensor is failed further in response to the sensor failure verification operation. In certain further embodiments, the sensor failure verification operation includes one or more operations such as averaging a number of sensor test results, incrementing a fault counter in response to a sensor test indicating a failed sensor, decrementing a fault counter in response to a sensor test indicating a passed sensor, integrating the fuel consumption estimate over a predetermined period of time of operation and comparing the integrated values to fluid level sensor rationality fault and / or pass thresholds, and modeling fluid storage in the fluid tank 206 and accounting for the storage in the sensor failure verification operation and / or rationality check operation.

[0026] Referring to FIG. 3 there is illustrated an example procedure 300 which may be implemented and performed, in whole or in part, in connection with procedure 200 and sensor resolution learning circuit operation 222. Procedure 300 begins at an operation 302 for receiving raw, pre-processed fluid level sensor readings from fluid level sensor 202.

[0027] From operation 302, procedure 300 continues at operation 304 to activate sensor resolution learning in response to one or more learning conditions being satisfied. For example, learning activation at operation 304 can require a tank fluid level based enable condition be satisfied to ensure a proper level of fluid is present in fluid tank 206 that will enable determination of sensor resolution. Learning activation at operation 304 may also require one or more abort conditions not being met. The abort conditions may include, for example, engine 102 being shut off, an existing sensor fault, a frozen tank condition, the presence or one or other fault conditions, etc.

[0028] Procedure 300 continues from operation 304 in response to enable conditions being met and abort conditions not being met at operation 308. Operation 308 includes performing multiple measurement functions based on the fluid level sensor readings received at operation 302. The measurement functions include an operation 310 to detect a sensor reading change, an operation 312 to record the sensor reading change, or delta, and the associated fluid level or fluid levels in tank 206. The measurement functions also include an operation 314 to compare the Page 7 of 20 133769351v1Attorney Docket No. CMI002-00102 / 23-0079-SRC sensor reading change and fluid level to a minimum number of counts of required measurements that are needed or desired to determine sensor resolution.

[0029] Procedure 300 continues at operation 316 to process the measurements determined from operation 308. Operation 316 includes a first processing operation 318 to calculate the average and the maximum of the measurements from operation 308. Operation 316 includes a second processing operation 320 to refer to a look-up table that cross-references sensor resolution numbers with the average sensor reading changes and associated changes in fluid level. Procedure 300 continues at operation 322 to output a single sensor resolution number obtained from the look-up table based on the calculated average and maximum of the sensor reading changes and associated changes in fluid level.

[0030] Referring to FIG. 4 there is illustrated an example procedure 400 which may be implemented and performed, in whole or in part, in connection with procedure 200 and tank geometry learning circuit operation 224. Procedure 400 includes an operation 402 for receiving multiple inputs. A first input 404 includes the sensor resolution number from output operation 322 of procedure 300 of the sensor resolution learning circuit operation 222. A second input 406 includes receiving the processed level sensor readings from input processing operation 212 of procedure 200. A third input 408 includes processed fluid consumption estimates from input processing operation 212 of procedure 200.

[0031] Procedure 400 continues at operation 410 to activate tank geometry learning in response to learning conditions being satisfied. For example, learning activation at operation 412 can require a tank fluid level based enable condition be satisfied to ensure a proper level of fluid is present in fluid tank 206. Learning activation at operation 414 may also require one or more abort conditions not being met. In an embodiment, operation 410 to activate learning can include the same or similar enable conditions and abort conditions as operation 304 of procedure 300.

[0032] Procedure 400 continues at operation 416 in response to the enable conditions being satisfied and one or more abort conditions not being met at operation 410. Operation 416 includes creating buckets for containing input data from operation 410. In an embodiment, buckets for input data are created for different fluid levels within the fluid tank 206. For example, operation 416 includes an operation 418 to look-up a reference for the bucket size to be used. Operation 416 also includes an operation 420 to create non-volatile memory store for the Page 8 of 20 133769351v1Attorney Docket No. CMI002-00102 / 23-0079-SRC input data in each bucket having a predetermined length. In an example embodiment, the memory store includes 5 arrays where each array is 100 elements long with the capability to support 100 buckets.

[0033] Procedure 400 continues at operation 422 to initiate learning the geometry of fuel tank 206 using the input data stored in the various fluid level buckets. Operation 422 includes an operation 424 to trigger a bucket that corresponds to the active fluid level in fluid tank 206. Fluid level readings from fluid level sensor 202 and associated fluid consumption estimates are accumulated in the corresponding active level buckets during operation of engine 104 at operation 426.

[0034] Operation 422 further includes an operation 428 to repeat filling of each active level bucket with input data including the fluid level readings from fluid level sensor 202 and associated fluid consumption estimates. In an embodiment, each active level bucket is filled a maximum number of times. In an embodiment, the maximum number of time is 5. Operation 422 also includes an operation 430 to provide a statistical consolidation of the learned volume for the fluid consumption amounts at each of the active fluid levels in fluid tank 206 for each bucket.

[0035] Procedure 400 continues at operation 432 to create a relationship between fluid consumption and the fluid level readings to learn fluid consumption amounts of the fluid tank at or between the various fluid levels. The relationship can be, for example, an estimate of the cross-sectional area of the fluid tank at each active fluid level, an estimate of the volume of the fluid tank at or between each active fluid level, a rate of change or area or volume of the fluid tank at and / or between active fluid levels, etc.

[0036] Referring to FIG. 5 there is illustrated an example procedure 500 which may be implemented and performed, in whole or in part, in connection with procedure 200 and tank volume learning circuit operation 226. Procedure 500 includes an operation 502 for the receiving relationship between fluid consumption and the fluid level reading created at operation 432 of procedure 400 during the tank geometry learning circuit operation 224.

[0037] Procedure 500 continues from operation 502 at operation 504 to activate tank volume learning in response to learning conditions being satisfied. For example, learning activation at operation 506 can require a tank fluid level based enable condition be satisfied to ensure a proper level of fluid is present in fluid tank 206. Learning activation at operation 508 may also require Page 9 of 20 133769351v1Attorney Docket No. CMI002-00102 / 23-0079-SRC one or more abort conditions not being met. In an embodiment, operation 504 to activate learning can include the same or similar enable conditions and abort conditions as operation 304 of procedure 300.

[0038] Procedure 500 continues from operation 504 at operation 510 to evaluate one or more conditions to be satisfied to calculate the volume of fluid tank 206. A first condition 512 includes a total number of learned fluid consumption amounts for fluid tank 206 being greater than a threshold value. A second condition 514 is that the total number of active level buckets with at least a minimum number of learned consumption values is greater than a minimum threshold number of buckets. In an embodiment, the minimum number of buckets is at least three buckets that possess the minimum number of required learned fluid consumption values.

[0039] A third condition 516 is the difference between the highest fluid level bucket with at least the minimum number of learned fluid consumption values and the lowest fluid level bucket with at least the minimum number of learned consumption values is greater than a threshold. For example, in order to learn the tank volume, the learned fluid consumption values should not be only from adjacent active levels of the fluid tank 206, but rather include at least one active level at or near the top of the fuel tank 206 (filled or nearly full condition) and at least one active level at or near the bottom of fuel tank 206 (empty or nearing empty condition.)

[0040] Procedure 500 continues from operation 510 at operation 518 in response to the conditions at operation 510 being satisfied. Operation 518 includes providing an output that corresponds to a calculation of the total volume of fluid tank 206 based on the learned fluid consumption values at various levels of fluid tank 206.

[0041] Based on the output of the diagnosis when a malfunction of the sensor is detected successfully, one or more of the following actions can be taken, among others. One action can include turning off fluid injection at the extreme case upon determining safe-harbor conditions. Another action includes turning down the fluid injection quantity using an instantaneous maximum limit or a percent based derate. Another action includes setting the fluid level value to a default. Another action include illuminating a malfunction lamp on the vehicle dashboard. Another action includes sending a message over the air to the operator or fleet management services. Another action includes changing engine operation calibrations to produce less NOx emissions. Page 10 of 20 133769351v1Attorney Docket No. CMI002-00102 / 23-0079-SRC

[0042] The systems and procedures disclosed herein may be employed with any variety of fluid level sensor and fluid tank size / geometry. Software re-design and / or calibration changes are not required for different fluid tank builds or applications is not required since sensor resolution, fluid tank geometry, and fluid tank volume are learned and are able to be adapted to any fluid tank build or geometry. In addition, since the diagnostic procedure is based on fluid consumption, diagnostics for high sensor output rationality (readings too high for active fluid level) and low sensor output rationality (readings too low for active fluid level) are also possible in addition to diagnosing a “stuck” or malfunctioning sensor.

[0043] It shall be appreciated that terms such as “a non-transitory memory,” “a non- transitory memory medium or media,” and “a non-transitory memory device” refer to a number of types of devices and storage mediums which may be configured to store information, such as data or instructions, readable or executable by a processor or other components of a computer system and that such terms include and encompass a single or unitary device or medium storing such information, multiple devices or media across or among which respective portions of such information are stored, and multiple devices or media across or among which multiple copies of such information are stored.

[0044] It shall be appreciated that terms such as “determine,” “determined,” “determining” and the like when utilized in connection with a control method or process, an electronic control system or controller, electronic controls, or components or operations of the foregoing refer inclusively to a number of acts, configurations, devices, operations, and techniques including, without limitation, calculation or computation of a parameter or value, obtaining a parameter or value from a lookup table or using a lookup operation, receiving parameters or values from a datalink or network communication, receiving an electronic signal (e.g., a voltage, frequency, current, or pulse-width modulation (PWM) signal) indicative of the parameter or value, receiving output of a sensor indicative of the parameter or value, receiving other outputs or inputs indicative of the parameter or value, reading the parameter or value from a memory location on a computer-readable medium, receiving the parameter or value as a run-time parameter, and / or by receiving a parameter or value by which the interpreted parameter can be calculated, and / or by referencing a default value that is interpreted to be the parameter value.

[0045] As illustrated by this detailed description, the present disclosure contemplates numerous embodiments, several examples of which shall now be further elucidated. A first Page 11 of 20 133769351v1Attorney Docket No. CMI002-00102 / 23-0079-SRC example embodiment is a diagnostic method for a fluid level sensor in a fluid tank of a vehicle includes: measuring a plurality of fluid levels in the fluid tank with the fluid level sensor; determining fluid consumption amounts associated with the measurements of the plurality of fluid levels; learning a sensor resolution of the fluid level sensor, a geometry of the fluid tank, and a volume of the fluid tank based on the plurality of fluid level measurements and the fluid consumption amounts; and outputting a diagnostic for the fluid level sensor based on the learned sensor resolution, the learned geometry of the fluid tank, and the learned volume of the fluid tank.

[0046] In an embodiment, the method includes outputting the diagnostic for the fluid level sensor based on assumed values for the sensor resolution, the geometry of the fluid tank, and the volume of the fluid tank while learning the sensor resolution of the fluid level sensor, the geometry of the fluid tank, and the volume of the fluid tank.

[0047] In an embodiment, the learning includes first learning the sensor resolution of the fluid level sensor, then learning the geometry of the fluid tank, and then learning the volume of the fluid tank.

[0048] In an embodiment, the method includes estimating a confidence metric for the fluid level sensor diagnostic based on the learning of the sensor resolution, the geometry of the fluid tank, and the volume of the fluid tank.

[0049] In a further embodiment, the method includes assigning a diagnostic margin based on the confidence metric; and determining thresholds for passing and failing the fluid level sensor diagnostic based on the diagnostic margin.

[0050] In an embodiment, the fluid tank contains diesel exhaust fluid for dosing into an aftertreatment system.

[0051] In an embodiment, learning the sensor resolution includes: detecting changes in output from the fluid level sensor; recording the changes in output from the fluid level sensor and changes in fluid levels in the fluid tank associated with the changes in output from the fluid level sensor; and determining the sensor resolution based on changes in output from the fluid level sensor and changes in the fluid levels in the fluid tank associated with the changes in output from the fluid level sensor.

[0052] In a further embodiment, the sensor resolution is determined based on an average of the changes in output from the fluid level sensor and associated changes in fluid levels in the Page 12 of 20 133769351v1Attorney Docket No. CMI002-00102 / 23-0079-SRC fluid tank and a maximum change in output from the fluid level sensor and associated change in fluid level in the fluid tank.

[0053] In a further embodiment, learning the tank geometry is based on the sensor resolution number, the measured fluid levels in the fluid tank, and the fluid consumption amounts, and determining a relationship between the fluid levels in the fluid tank and fluid consumption amounts associated with the fluid levels in the fluid tank.

[0054] In yet a further embodiment, learning the tank geometry act including learning a relationship for fluid consumption amounts at each of a plurality of fluid levels in the fluid tank.

[0055] In yet a further embodiment, learning the tank volume is based on determining the relationship between the fluid consumption amounts and the plurality of fluid levels in the fluid tank a plurality of times for each of a plurality of fluid levels in the fluid tank.

[0056] In yet a further embodiment, learning the tank volume requires a difference between a highest fluid level having a plurality of learned relationships between fluid consumption and the fluid level in the fluid tank and a lowest fluid level having a plurality of learned relationships between fluid consumption and the fluid level in the fluid tank being greater than a threshold.

[0057] According to another aspect of the disclosure, a system for diagnosing a fluid level sensor in a fluid tank of a vehicle is provided. The system includes an electronic control system including at least one electronic control unit configured to execute instructions stored one or more non-transitory memory media to: measure a plurality of fluid levels in the fluid tank with the fluid sensor; determine fluid consumption amounts associated with the measurements of the plurality of fluid levels in the fluid tank; learn a sensor resolution of the fluid level sensor, learn a geometry of the fluid tank, and learn a volume of the fluid tank based on the plurality of fluid level measurements and the fluid consumption amounts; and output a diagnostic for the fluid level sensor based on the learned sensor resolution, the learned geometry of the fluid tank, and the learned volume of the fluid tank.

[0058] In an embodiment, the electronic control system is configured to: output the diagnostic for the fluid level sensor based on assumed values for the sensor resolution, the geometry of the fluid tank, and the volume of the fluid tank while learning the sensor resolution of the fluid level sensor, the geometry of the fluid tank, and the volume of the fluid tank. Page 13 of 20 133769351v1Attorney Docket No. CMI002-00102 / 23-0079-SRC

[0059] In a further embodiment, the electronic control system is configured to first learn the sensor resolution of the fluid level sensor, then learn the geometry of the fluid tank, and then learn the volume of the fluid tank.

[0060] In a further embodiment, the electronic control system is configured to estimate a confidence metric for the fluid level sensor diagnostic based on the learning of the sensor resolution, the geometry of the fluid tank, and the volume of the fluid tank.

[0061] In yet a further embodiment, the electronic control system is configured to: assign a diagnostic margin based on the confidence metric; and determine thresholds for passing and failing the fluid level sensor diagnostic based on the diagnostic margin.

[0062] In an embodiment, the electronic control system is configured to learn the sensor resolution by: detecting changes in output from the fluid level sensor; recording the changes in output from the fluid level sensor and changes in fluid levels in the fluid tank associated with the changes in output from the fluid level sensor; and determining the sensor resolution based on changes in output from the fluid level sensor and changes in the fluid levels in the fluid tank associated with the changes in output from the fluid level sensor.

[0063] In a further embodiment, the electronic control system is configured to learn the tank geometry based on the sensor resolution number, the measured fluid levels in the fluid tank, and the fluid consumption amounts, and determining a relationship between the fluid levels in the fluid tank and the fluid consumption amounts associated with the fluid levels in the fluid tank.

[0064] In yet a further embodiment, the electronic control system is configured to learn the tank volume based on the determining the relationship between the fluid consumption amounts and the plurality of fluid levels in the fluid tank a plurality of times for each of a plurality of fluid levels in the fluid tank.

[0065] While example embodiments of the disclosure have been illustrated and described in detail in the drawings and foregoing description, the same is to be considered as illustrative and not restrictive in character, it being understood that only certain example embodiments have been shown and described and that all changes and modifications that come within the spirit of the claimed inventions are desired to be protected. It should be understood that while the use of words such as preferable, preferably, preferred or more preferred utilized in the description above indicates that the feature so described may be more desirable, it nonetheless may not be Page 14 of 20 133769351v1Attorney Docket No. CMI002-00102 / 23-0079-SRC necessary and embodiments lacking the same may be contemplated as within the scope of the invention, the scope being defined by the claims that follow. In reading the claims, it is intended that when words such as “a,” “an,” “at least one,” or “at least one portion” are used there is no intention to limit the claim to only one item unless specifically stated to the contrary in the claim. When the language “at least a portion” and / or “a portion” is used the item can include a portion and / or the entire item unless specifically stated to the contrary. Page 15 of 20 133769351v1

Claims

Attorney Docket No. CMI002-00102 / 23-0079-SRC WHAT IS CLAIMED IS:

1. A diagnostic method for a fluid level sensor in a fluid tank of a vehicle, the method comprising: measuring a plurality of fluid levels in the fluid tank with the fluid level sensor; determining fluid consumption amounts associated with the measurements of the plurality of fluid levels; learning a sensor resolution of the fluid level sensor, a geometry of the fluid tank, and a volume of the fluid tank based on the plurality of fluid level measurements and the fluid consumption amounts; and outputting a diagnostic for the fluid level sensor based on the learned sensor resolution, the learned geometry of the fluid tank, and the learned volume of the fluid tank.

2. The method of claim 1, further comprising outputting the diagnostic for the fluid level sensor based on assumed values for the sensor resolution, the geometry of the fluid tank, and the volume of the fluid tank while learning the sensor resolution of the fluid level sensor, the geometry of the fluid tank, and the volume of the fluid tank.

3. The method of claim 1, wherein the learning includes first learning the sensor resolution of the fluid level sensor, then learning the geometry of the fluid tank, and then learning the volume of the fluid tank.

4. The method of claim 1, further comprising estimating a confidence metric for the fluid level sensor diagnostic based on the learning of the sensor resolution, the geometry of the fluid tank, and the volume of the fluid tank.

5. The method of claim 4, further comprising; assigning a diagnostic margin based on the confidence metric; and determining thresholds for passing and failing the fluid level sensor diagnostic based on the diagnostic margin. Page 16 of 20 133769351v1Attorney Docket No. CMI002-00102 / 23-0079-SRC 6. The method of claim 1, wherein the fluid tank contains diesel exhaust fluid for dosing into an aftertreatment system.

7. The method of claim 1, wherein learning the sensor resolution includes: detecting changes in output from the fluid level sensor; recording the changes in output from the fluid level sensor and changes in fluid levels in the fluid tank associated with the changes in output from the fluid level sensor; and determining the sensor resolution based on changes in output from the fluid level sensor and changes in the fluid levels in the fluid tank associated with the changes in output from the fluid level sensor.

8. The method of claim 7, wherein the sensor resolution is determined based on an average of the changes in output from the fluid level sensor and associated changes in fluid levels in the fluid tank and a maximum change in output from the fluid level sensor and associated change in fluid level in the fluid tank.

9. The method of claim 7, wherein learning the tank geometry is based on the sensor resolution number, the measured fluid levels in the fluid tank, and the fluid consumption amounts, and determining a relationship between the fluid levels in the fluid tank and fluid consumption amounts associated with the fluid levels in the fluid tank.

10. The method of claim 9, wherein learning the tank geometry act including learning a relationship for fluid consumption amounts at each of a plurality of fluid levels in the fluid tank.

11. The method of claim 9, wherein learning the tank volume is based on determining the relationship between the fluid consumption amounts and the plurality of fluid levels in the fluid tank a plurality of times for each of a plurality of fluid levels in the fluid tank.

12. The method of claim 11, wherein learning the tank volume requires a difference between a highest fluid level having a plurality of learned relationships between fluid consumption and Page 17 of 20 133769351v1Attorney Docket No. CMI002-00102 / 23-0079-SRC the fluid level in the fluid tank and a lowest fluid level having a plurality of learned relationships between fluid consumption and the fluid level in the fluid tank being greater than a threshold.

13. A system for diagnosing a fluid level sensor in a fluid tank of a vehicle, the system comprising: an electronic control system including at least one electronic control unit configured to execute instructions stored one or more non-transitory memory media to: measure a plurality of fluid levels in the fluid tank with the fluid sensor; determine fluid consumption amounts associated with the measurements of the plurality of fluid levels in the fluid tank; learn a sensor resolution of the fluid level sensor, learn a geometry of the fluid tank, and learn a volume of the fluid tank based on the plurality of fluid level measurements and the fluid consumption amounts; and output a diagnostic for the fluid level sensor based on the learned sensor resolution, the learned geometry of the fluid tank, and the learned volume of the fluid tank.

14. The system of claim 13, wherein the electronic control system is configured to: output the diagnostic for the fluid level sensor based on assumed values for the sensor resolution, the geometry of the fluid tank, and the volume of the fluid tank while learning the sensor resolution of the fluid level sensor, the geometry of the fluid tank, and the volume of the fluid tank.

15. The system of claim 14, wherein the electronic control system is configured to first learn the sensor resolution of the fluid level sensor, then learn the geometry of the fluid tank, and then learn the volume of the fluid tank.

16. The system of claim 14, wherein the electronic control system is configured to estimate a confidence metric for the fluid level sensor diagnostic based on the learning of the sensor resolution, the geometry of the fluid tank, and the volume of the fluid tank. Page 18 of 20 133769351v1Attorney Docket No. CMI002-00102 / 23-0079-SRC 17. The system of claim 16, wherein the electronic control system is configured to: assign a diagnostic margin based on the confidence metric; and determine thresholds for passing and failing the fluid level sensor diagnostic based on the diagnostic margin.

18. The system of claim 13, wherein the electronic control system is configured to learn the sensor resolution by: detecting changes in output from the fluid level sensor; recording the changes in output from the fluid level sensor and changes in fluid levels in the fluid tank associated with the changes in output from the fluid level sensor; and determining the sensor resolution based on changes in output from the fluid level sensor and changes in the fluid levels in the fluid tank associated with the changes in output from the fluid level sensor.

19. The system of claim 18, wherein the electronic control system is configured to learn the tank geometry based on the sensor resolution number, the measured fluid levels in the fluid tank, and the fluid consumption amounts, and determining a relationship between the fluid levels in the fluid tank and the fluid consumption amounts associated with the fluid levels in the fluid tank.

20. The system of claim 19, wherein the electronic control system is configured to learn the tank volume based on the determining the relationship between the fluid consumption amounts and the plurality of fluid levels in the fluid tank a plurality of times for each of a plurality of fluid levels in the fluid tank. Page 19 of 20 133769351v1

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