Liquid level sensor assembly

Abstract

A level sensor assembly (10) is used to measure physical properties that indicate the quality of a urea solution (AdBlue / DEF), at least a portion of which is inserted into a tank (50). The level sensor assembly includes: a tube seat unit (12) installed in a hole in a tank; a heating tube (20) inserted in the tank for heating or thawing the urea solution in the tank and one or more suction tubes (22) for drawing urea solution from the tank, the heating tube and suction tubes being connected to the tube seat unit; a level sensor for measuring the level of urea solution in the tank; a removable UQS sensor (30) installed in the tube seat unit and at least partially immersed in a urea solution pool (32) in the tube seat unit; the pool including a compressible and / or expandable bottom (34); the UQS sensor and the pool being housed in a flushing chamber (60) with an eccentrically configured suction channel (62) for flushing with urea solution received from the tank, the suction channel extending between the pool and the suction side (66) of the level sensor assembly.

Description

Technical Field

[0001] This invention relates to a level sensor assembly for measuring physical properties representing the quality of a urea solution (AdBlue / DEF). At least a portion of the level sensor assembly is inserted into a tank. The level sensor assembly includes: a tube seat unit installed in a hole in the tank; a heating tube inserted into the tank for heating or thawing the urea solution in the tank; and one or more suction tubes for drawing urea solution from the tank, the heating tube and the suction tubes being connected to the tube seat unit; and a level sensor for measuring the level of the urea solution in the tank.

[0002] This invention relates to integrated urea concentration ( / AdBlue quality) sensors (UQS) and tank level sensors, which can preferably also be assembled from separate modules. The tank level sensor includes, for example, a level sensor for drawing liquid from an AdBlue tank and for returning liquid to the AdBlue tank. The UQS includes, for example, a sensor unit with integrated electronics. Background Art

[0003] The automotive industry imposes stricter emission requirements on diesel engines, typically requiring the use of SCR (Selective Catalytic Reduction) systems. The catalytic converter used is usually called AdBlue or Diesel Exhaust Fluid (DEF). Euro VI standards specify on-board monitoring of AdBlue / DEF quality in vehicles. Standard AdBlue tank sensors typically monitor tank level and can be combined with a urea quality sensor (UQS), usually fixed to the sensor's immersion section. In current versions, due to the high integration of the quality and level sensors, the combined unit must be completely replaced in the event of a failure in either the level or quality detection system. Secondly, development, integration, and procurement costs become expensive. Thirdly, the UQS installed in the tank is frequently affected by air bubbles in or near the sensor surface, or air bubbles forming in or near the sensor surface within the tank, causing reading distortion.

[0004] Publicly available technology content

[0005] Several devices for measuring the concentration of urea solutions are known in the art.

[0006] US 9297686 B1 discloses an apparatus for determining at least a first and a second property of a fluid associated with a tank, comprising a mounting head adapted to be connected to the tank, a housing extending from the mounting head, and an integral chamber formed therein. The chamber is in fluid communication between the tank and a downstream device of a vehicle or equipment associated with the tank. A sensor module may be mounted in the chamber to measure different parameters of the fluid. Other modules may be interchanged with the sensor module to perform different operations related to the apparatus and / or the fluid.

[0007] US 2016123929 A1 discloses an apparatus for measuring the quality of urea solution in a vehicle urea tank or for measuring the quality of urea solution from a tank, comprising a chamber, at least one ultrasonic transceiver configured to vertically emit ultrasonic waves within the chamber, and a deflector extending above the transceiver within the chamber. The chamber includes an inlet for filling the chamber with urea solution such that the urea solution level in the chamber at least reaches the deflector.

[0008] CN 204591423 U discloses a urea tank with integrated urea quality detection, including a main body and a liquid level sensor installed within it. The liquid level sensor's signal output is connected to a control system. A urea quality sensor is also installed within the main body, and its signal output is connected to the control system. This urea tank utilizes an integrated urea quality sensor, integrating the output signals from the quality sensor and the liquid level sensor. The signal output is then sent to the control system, enabling accurate judgment and control of the urea solution quality. It can strictly adhere to national standards for quality testing, implement relevant national policies, and allow for real-time monitoring and adjustment of the urea solution's purity. This effectively controls the SCR system's treatment of pollutants such as NOx, protecting environmental health.

[0009] US Patent 2013220467 A1 discloses an automotive selective catalytic reduction (SCR) system assembly, including a retainer for receiving an SCR system sensor. The retainer has a tube, a chamber, and a clamp. The tube receives inlet fluid from a first SCR line and directs outflow fluid to a second SCR line. A passage is located within the tube. The chamber has an interior for receiving the SCR system sensor and has an opening. The clamp has a portion that can be moved into and out of the chamber opening for holding and releasing the SCR system sensor inside the chamber.

[0010] Also referenced is WO2019 / 070130 A1, which forms the basis of this invention.

[0011] Purpose of the invention

[0012] A UQS device is disclosed, which can be positioned externally to a DEF / AdBlue tank, preferably integrated as a detachable unit within a level sensor head. The modular design allows for the use of near-standard, mass-produced UQS, but minor modifications are also possible. The urea level sensor head design can be configured to fully integrate the detachable UQS unit. The sensor continuously detects the quality of the DEF / AdBlue liquid guided to the quality sensor. The DEF / AdBlue liquid can be all or part of the circulating liquid returned from (or supplied to) an SCR system.

[0013] The sensor can be positioned in the sensor head to measure the urea concentration in the liquid in conjunction with the return / feed flow of DEF / AdBlue. The sensor is partially or completely immersed in a chamber / liquid pool containing DEF / AdBlue, which is designed to accommodate liquid / solid expansion caused by icing scenarios.

[0014] The chamber or chamber portion containing the liquid (DEF / AdBlue) may have a geometry that allows for liquid expansion, or it may be constructed of a flexible material that allows for expansion / compression, and a spring device may be mounted on the outside or inside of the flexible material to ensure that the elastic material fully retracts or collapses. The chamber is part of a closed loop for the return or supply of DEF / AdBlue to the tank or SCR system.

[0015] Apart from the liquid outlet, the chamber or chamber portion containing the liquid (DEF / AdBlue) may have a geometry that allows for liquid expansion, wherein a small vent hole may be provided at the bottom, allowing the liquid (DEF / AdBlue) to be completely drained into the tank after the system is shut down. The drain volume will be significantly less than the minimum amount of liquid (DEF / AdBlue) normally guided into the chamber.

[0016] The chamber or chamber portion containing the liquid (DEF / AdBlue) may have a geometry that allows the liquid to expand, or may be made of a flexible material that allows expansion / compression, and may have a small vent hole that allows the liquid (DEF / AdBlue) to be completely drained into the tank after the system is shut down.

[0017] A known problem associated with measuring AdBlue concentration is that air bubbles in the urea solution can cause issues with accurate and stable readings. Bubbles form during filling, settling, or splashing caused by movement, and are primarily present in the can or on the suction side. In some cases, bubbles form within the dosing unit and are expelled on the reflux side.

[0018] Therefore, the object of the present invention is to provide a device capable of removing such bubbles, so that bubbles do not accumulate in the measurement area of ​​the UQS sensor.

[0019] The key advantage is that the UQS sensor is easy to install and subsequently replace or repair, without having to remove the entire DEF / AdBlue sensor assembly from the tank.

[0020] The advantages of the technology disclosed in this application can be summarized as follows:

[0021] a) This work can be performed by combining parts that are close to the "standard" for mass production.

[0022] b) Easy to install; and there are no strict specifications for electronic components that are immersed in corrosive fluids.

[0023] c) Significantly reduced bubble formation on the sensor surface or in the liquid.

[0024] d) The quality sensor unit is easy to replace in case of failure.

[0025] e) Compared to in-can UQS solutions, it allows for earlier detection / sensing of AdBlue / DEF quality in the case of frozen cans.

[0026] f) An expandable / compressible chamber / liquid pool or chamber design (which may include a vent) will ensure that the UQS unit or sensor head is not damaged by icing. Adding a venting function will eliminate the need to thaw frozen AdBlue / DEF around the UQS sensor. Summary of the Invention

[0027] At least some of these objectives are achieved by integrating the UQS into the level sensor's socket using a modular design. The sensor comprises the UQS and a level sensor based on reed switches or AMR technology activated by a magnetic float. Data collected by the sensor is transmitted to the vehicle's OBD system. The level sensor also includes a socket unit and stainless steel tubing for heating / thawing AdBlue / DEF, suction, and reflux. Typical data provided by the sensor includes the percentage of urea in the solution, the temperature of the DEF / AdBlue, and measurements of the level in the tank.

[0028] The UQS module can be combined with AdBlue sensors in various implementations adopted by different OEMs and includes a socket made of PA66-GF33, or rubber, or variations / alternatives of these materials, and / or combined with a metal structure. The modular design allows for easy installation and replacement of the UQS.

[0029] The above objective is achieved using a level sensor assembly for measuring physical properties representing the quality of a urea solution (AdBlue / DEF). At least a portion of the level sensor assembly is inserted into a tank. The level sensor assembly includes: a tube seat unit mounted in an orifice of the tank; a heating tube inserted into the tank for heating or thawing the urea solution in the tank; and one or more suction tubes for drawing urea solution from the tank, the heating tube and suction tubes being connected to the tube seat unit; and a level sensor for measuring the level of the urea solution in the tank. A removable UQS sensor is mounted in the tube seat unit, the UQS sensor being at least partially immersed in a urea solution pool within the tube seat unit, wherein the pool in the tube seat unit includes a compressible and / or expandable bottom. The invention is characterized in that the UQS sensor and the pool are housed in a flushing chamber having an eccentrically arranged suction channel for flushing with urea solution received from the tank, and wherein the at least one suction channel extends between the pool and the suction side of the level sensor assembly.

[0030] The bottom of the liquid pool may include a centrally located hole for receiving urea solution, wherein a suction channel is eccentrically positioned relative to the hole.

[0031] In one embodiment, the bottom of the flushing chamber may include a centrally located inlet hole for receiving urea solution from the tank, with a suction channel eccentrically positioned relative to the hole.

[0032] The bottom of the flushing chamber may also include a resilient pad having an opening aligned with the flushing chamber inlet, wherein the inlet is connected to at least one suction tube for drawing urea solution from the tank.

[0033] The inlet of the suction channel is located on the inner wall of the flushing chamber.

[0034] Additionally, the liquid pool in the pipe unit can be connected to an inlet for urea solution reflux and an overflow outlet for urea solution to be discharged from the liquid pool into the tank.

[0035] The bottom may include one or more elastic cups made of elastic material, which can expand during freezing in the liquid pool and retract when the ice melts.

[0036] Alternatively, the bottom may include one or more elastic cups made of a compressible material that are compressible during freezing in the liquid pool and expandable as the ice melts.

[0037] The liquid pool in the tube holder unit may also include a drain hole for draining urea solution into the AdBlue tank when not in use.

[0038] The liquid pool in the tube seat unit can also be the liquid pool for the urea solution to be sent to the SCR system.

[0039] The level sensor may include a tube with a reed switch or AMR technology, activated by a magnetic float. Attached Figure Description

[0040] Embodiments of the invention will now be described by way of example only with reference to the following figures, wherein:

[0041] Figure 1 The upper part of the liquid level sensor assembly and the tube seat unit are shown in cross-sectional view.

[0042] Figure 2 A top perspective view of the tube seat unit with the liquid level sensor assembly is shown.

[0043] Figure 3 An example of the entire level sensor assembly installed in the tank is shown.

[0044] Figure 4 A tube seat unit according to the present invention is shown.

[0045] Figure 5 Shown in sectional view Figure 4 It is part of the tube socket unit and has a UQS sensor.

[0046] Figure 6 Shown in sectional view Figure 4 It is part of the tube socket unit and does not have a UQS sensor.

[0047] Figure 7 It shows along Figure 4 The middle dashed line cuts off Figure 4 A partial sectional view of the pipe seat unit.

[0048] Figure 8 It shows Figure 4 Top view of the tube socket unit. Detailed Implementation

[0049] Figure 3 A typical AdBlue tank 50 equipped with a level sensor assembly 10 is shown, wherein the level sensor assembly 10 measures physical properties indicating the quality of a urea solution (AdBlue / DEF). The tank 50 also includes an inlet or opening 52 for filling with the urea solution. At least a portion of the level sensor assembly 10 is inserted into the tank 50, and a socket unit 12 of the level sensor assembly 10 is mounted in a hole at the top of the tank 50 and extends out of the hole. The socket unit 12 is equipped with a connector 40 for relaying the level measurement signal and a connector 42 for relaying the AdBlue quality measurement signal. The level sensor assembly 10 is also connected to the vehicle's SCR (Selective Catalytic Reduction) system.

[0050] The design and material composition of the tube socket structure can vary depending on the OEM.

[0051] The level sensor assembly 10 also includes a heating tube 20 inserted in the tank 50 for heating or thawing the urea solution in the tank 50 and one or more suction tubes 22 for drawing urea solution from the tank 50, the heating tube 20 and the suction tubes 22 being connected to the tube seat unit 12. Figure 2 An example of a heating tube 20 with a coil is shown, but many other designs are also possible.

[0052] The level sensor assembly 10 also includes a level sensor for measuring the level of urea solution in tank 50, which is connected to a connector 40 for relaying the level measurement signal. The level sensor may include a tube 24 with reed switch or AMR technology, which is activated by a magnetic float 26. Figure 2 This example of a liquid level sensor is shown, but many other designs are also possible.

[0053] A removable urea quality sensor 30 (hereinafter referred to as the UQS sensor) is installed in the pipe socket unit 12, wherein the UQS sensor 30 is at least partially immersed in the chamber or reservoir 32 of the urea solution in the pipe socket unit 12. The UQS sensor 30 is inserted into the opening in the pipe socket unit 12 by screwing or otherwise securing it so that it is directly above and in contact with the urea solution reservoir 32.

[0054] The UQS sensor 30 can be a sensor that uses special optical technology to detect changes in urea concentration (e.g., as small as + / - 2%) and can operate at temperatures ranging from, for example, -10°C to +85°C. The optical measurement principle is robustly resistant to dirt and moving fluids (including gasoline, diesel, or coolant). The sensor is capable of continuously measuring AdBlue / DEF quality (the proportion of urea in a solution or erroneous medium).

[0055] The liquid pool 32 in the pipe seat unit 12 may be a urea solution return pool for returning urea solution (from the SCR system) to tank 50, and has or is connected to a urea solution return inlet 36 and an overflow outlet 38 for discharging urea solution from the liquid pool 32 into AdBlue tank 50.

[0056] A typical AdBlue tank 50 is mounted externally to the vehicle, usually next to the fuel tank, making the urea solution prone to freezing and / or thawing. Therefore, in the event of freezing of the urea solution, it is preferable to equip the liquid pool 32 in the pipe seat unit 12 with a compressible and / or expandable bottom 34 to allow the liquid to expand.

[0057] The bottom 34 may also be made of a flexible material that allows expansion or compression; alternatively, a spring or similar element may be mounted on the outside or inside of the flexible material to ensure that the elastic material fully retracts or collapses. Therefore, the bottom 34 may include one or more elastic cups 34a, 34b. The elastic cups 34a, 34b are preferably made of an elastic or compressible material that returns to its original shape when unaffected. A spring may be used as an additional means to ensure that the elastic cups 34a, 34b retract or collapse back to their original shape.

[0058] like Figure 1 As shown, the elastic cups 34a and 34b are inverted, that is, with the bottom facing up.

[0059] In one embodiment, the elastic cups 34a, 34b are made of a compressible material and are arranged to compress when frozen in the liquid pool 32 and expand when the ice melts.

[0060] However, in the second embodiment, the elastic cups 34a and 34b are made of elastic material and are arranged to expand in the event of freezing in the liquid pool 32 and retract when the ice melts.

[0061] The elastic material allows the flexible bottom 34 to expand to accommodate the increased volume of ice. If the material is compressed during freezing, the wall thickness or compressible material in the liquid pool 32 will be compressed to provide additional space during freezing.

[0062] In addition to the overflow drain 38, the liquid reservoir 32 in the pipe seat unit 12 may also include a drain hole (not shown) for draining urea solution into the AdBlue tank 50 when not in use. The overflow drain 38 and the drain hole may be combined with each other or integrated into one unit.

[0063] In an alternative embodiment (not shown) and if sufficient liquid flow can be maintained, the liquid pool 32 in the socket unit 12 may be a liquid pool for filling the tank with urea solution, i.e., the inlet 52 of the tank 50 is connected to the socket unit 12 or the urea solution is injected into the tank through the socket unit 12.

[0064] The liquid reservoir 32 in the pipe seat unit 12 can be a liquid reservoir for the urea solution to be fed to the SCR system, thereby ensuring the quality of the urea solution delivered to the SCR system.

[0065] Figures 4 to 8 An embodiment of the tube seat unit 12 according to the present invention is shown, the tube seat unit being equipped with a flushing chamber 60. Figure 4 An overview of the tube seat unit 12 is shown, wherein the flushing chamber is indicated by reference numeral 60, and reference numeral 66 indicates the suction side or at least the direction of the urea solution toward the suction side.

[0066] Especially for reference Figure 5 and Figure 6In this embodiment, the flushing chamber 60 includes an inlet port 64a in its lower portion, which connects to the at least one suction pipe 22 for drawing urea solution from the tank 50. A connection portion 70 for the level measurement signal forwarding connector 40 and the AdBlue quality measurement signal forwarding connector 42 is disposed above the upper portion of the flushing chamber 60. The upper portion may be a cap threaded onto the lower portion. The level sensor assembly 10 may be connected to the vehicle's SCR (Selective Catalytic Reduction) system as mentioned above.

[0067] The liquid pool 32 includes a bottom 34 with an elastic seat 34c, an elastic pad or an elastic membrane, having similar compressible and / or expandable features as disclosed above. Figure 5 and Figure 6 An embodiment of the resilient pad 34c is specifically shown. The resilient pad 34c has an orifice 64b aligned with the inlet orifice 64a of the flushing chamber 60, thereby allowing urea solution to flow from the suction tube 22 into the liquid pool 32.

[0068] like Figure 5 As shown, the flushing chamber 60 houses the UQS sensor 30, and the UQS sensor can be connected to the upper part of the flushing chamber 60. The flushing chamber 60 also houses a liquid pool 32 in its lower part.

[0069] The flushing chamber 60 has an eccentrically positioned suction channel 62 extending between the liquid pool 32 and the external suction side 66. The suction side 66 may be located outside the tube seat unit 12 of the level sensor assembly. Urea solution received from tank 50 is drawn from the liquid pool 32 into the inlet 62a on the inner chamber wall 60a of the flushing chamber 60, passes through the suction channel 62, and then flows out from the outlet to the external suction side 66. Figure 6 As shown, the inlet 62a on the inner wall 60a of the flushing chamber 60 can be an inlet with an elongated slit. The suction of urea solution through the suction channel 62 provides a combination of flushing and swirling, which removes air bubbles from the measuring area of ​​the UQS sensor 30 (i.e., from the liquid pool 32).

[0070] The flushing chamber 60 may be installed into the pipe socket unit 12, or the flushing chamber 60 may be an integral part of the pipe socket unit 12.

Claims

1. A level sensor assembly (10) for measuring physical properties representing the quality of a urea solution (AdBlue / DEF), at least a portion of the level sensor assembly (10) being inserted into a tank (50), the level sensor assembly (10) comprising: The pipe seat unit (12) is installed in the hole of the tank (50). A heating tube (20) is inserted into the tank (50) for heating or thawing the urea solution, and one or more suction tubes (22) are used to draw urea solution from the tank (50). The heating tube (20) and the suction tubes (22) are connected to the tube seat unit (12). Level sensors (24, 26) are used to measure the level of urea solution in tank (50). A detachable UQS sensor (30) is installed in the tube socket unit (12), and the UQS sensor (30) is at least partially immersed in a pool (32) of urea solution in the tube socket unit (12). The liquid pool (32) in the pipe seat unit (12) includes a compressible and / or expandable bottom (34), wherein, The UQS sensor (30) and the liquid pool (32) are housed in a flushing chamber (60) having an eccentrically positioned suction channel (62) for flushing with urea solution received from the tank (50), the at least one suction channel (62) extending between the liquid pool (32) and the suction side (66) of the liquid level sensor assembly.

2. The liquid level sensor assembly (10) according to claim 1, wherein, The bottom (34) of the flushing chamber (60) includes a centrally located inlet hole (64a) for receiving urea solution from the tank (50), and a suction channel (62) is eccentrically positioned relative to the inlet hole (64).

3. The liquid level sensor assembly (10) according to claim 2, wherein, The bottom (34) of the flushing chamber (60) includes an elastic pad (34c) having a hole (64b) aligned with the inlet hole (64a) of the flushing chamber (60), and the inlet hole (64a) is connected to at least one suction tube (22) for drawing urea solution from the tank (50).

4. The liquid level sensor assembly (10) according to claim 1, wherein, The inlet (62a) of the suction channel (62) is located on the inner wall (60a) of the flushing chamber (60).

5. The liquid level sensor assembly (10) according to claim 1, wherein, The liquid pool (32) in the pipe seat unit (12) is connected to an inlet (36) for reflux of urea solution and an overflow outlet (38) for urea solution to be discharged from the liquid pool (32) into the tank (50).

6. The liquid level sensor assembly (10) according to claim 1, wherein, The bottom (34) includes one or more elastic cups (34a, 34b) made of elastic or compressible material, which can expand or compress during freezing in the liquid pool (32) and retract when the ice melts.

7. The liquid level sensor assembly (10) according to claim 1, wherein, The liquid pool (32) in the pipe seat unit (12) includes a drain hole for draining urea solution into the AdBlue tank when not in use.

8. The liquid level sensor assembly (10) according to claim 1, wherein, The liquid pool (32) in the pipe seat unit (12) is the liquid pool for the urea solution to be sent to the SCR system.

9. The liquid level sensor assembly (10) according to claim 1, wherein, The level sensor includes a tube with a reed switch or AMR technology and activated by a magnetic float.

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