Anti-freezing urea pressure sensor with built-in heat conduction insert
The antifreeze urea pressure sensor with a built-in thermal conductive insert addresses the issue of uncontrolled freezing by managing the freezing order of the urea solution, enhancing heat dissipation and protecting the pressure-sensitive element from damage.
Patent Information
- Application Number
- CN202411136588.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-08-19
- Publication Date
- 2024-12-20
AI Technical Summary
Existing urea pressure sensors are prone to damage due to uncontrolled freezing of urea solution, which expands and exerts force on the pressure-sensitive element, as the freezing order of the solution affects the magnitude of the force acting on the element.
An antifreeze type urea pressure sensor with a built-in thermal conductive insert that includes an elastic member and a cold expansion component to manage the freezing order of the urea solution, enhancing heat dissipation and protecting the pressure-sensitive element by ensuring the solution near it freezes first.
The solution effectively reduces the expansion force on the pressure-sensitive element by prioritizing the freezing of urea solution near it, thereby minimizing damage and maintaining pressure measurement accuracy.
Smart Images
Figure CN119164546A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of urea pressure sensors, in particular to an antifreeze type urea pressure sensor with a built-in heat-conducting insert. Background Art
[0002] The urea pressure sensor is a component that measures the pressure of the urea solution in the vehicle. When the ambient temperature is low, the urea solution will freeze, causing the volume of the solution to expand and squeeze the pressure-sensitive element in the sensor. When freezing occurs, the freezing order of the urea solution, that is, whether the side close to the pressure-sensitive element freezes first or last, will be related to the magnitude of the force acting on the pressure-sensitive element, so the freezing order of the urea solution needs to be controlled. Summary of the invention
[0003] Purpose of the invention: In order to overcome the deficiencies in the prior art, the present invention provides an antifreeze type urea pressure sensor with a built-in thermal conductive insert, which is intended to control the freezing order of the urea solution in the sensor.
[0004] Technical solution: To achieve the above-mentioned purpose, the antifreeze type urea pressure sensor with built-in heat-conducting insert of the present invention comprises a sensor housing, a liquid inlet channel is provided in the sensor housing, a pressure-sensitive element is provided at the end of the liquid inlet channel, and the urea solution can flow to the pressure-sensitive element along the liquid inlet channel; the volume of the urea solution is related to the temperature, and an elastic part is provided in the liquid inlet channel, and the elastic part can deform and shrink to adapt to the volume change of the urea solution; an insert is also provided in the sensor housing, and the insert is made of heat-conducting material, and has an internal connection part and an external connection part, the internal connection part is connected to the pressure-sensitive element, and the external connection part is connected to the outside world, so that the pressure-sensitive element can conduct heat to the outside world through the insert.
[0005] Furthermore, the insert is arranged outside the pressure-sensitive element, the inner wall of the insert is the inner connection part, and the inner wall of the insert is connected to the side wall of the pressure-sensitive element.
[0006] Furthermore, the sensor housing is composed of a shell base and a shell cover, there is a slit between the shell base and the shell cover, the outer wall of the insert is the external connection part, and part of the outer wall of the insert is exposed to the outside through the slit.
[0007] Furthermore, the inner side of the lower edge of the shell cover has a bevel, the outer side of the upper edge of the shell base has a bevel, the lower edge of the shell cover and the upper edge of the shell base are separated by a gap to form an oblique slit; there is a cold expansion member between the insert and the shell cover, the cold expansion member can expand at low temperatures, push the shell cover outward and squeeze the insert inward, so that the slit between the shell cover and the shell base expands, and the insert is squeezed to fit tightly against the pressure-sensitive element.
[0008] Furthermore, an annular groove is provided on the outer wall of the insert, and an annular space for accommodating the cold expansion member is formed between the annular groove and the inner wall of the shell cover, and the cold expansion member is correspondingly placed in the annular groove.
[0009] Furthermore, the cold expansion member comprises an annular elastic sac, which is correspondingly placed in the annular groove; the elastic sac contains cold expansion liquid inside, which can freeze and expand at low temperature.
[0010] Furthermore, the melting point of the cooled expansion liquid is higher than the melting point of the urea solution.
[0011] Furthermore, an inner bracket is arranged in the sensor housing, the lower end of the insert is embedded in the shell base, the upper end of the insert hooks the inner bracket, the inner bracket presses the pressure sensing element in the shell base, and the shell cover covers the inner bracket and is fixedly connected to the inner bracket.
[0012] Furthermore, the insert is arranged on the inner bracket, and the inner wall of the insert is connected to the outer wall of the inner bracket; an inward-shrinking notch is provided on the inner bracket, and the inward-shrinking notch is opposite to the position of the cold expansion member, and the insert can be deformed towards the inward-shrinking notch when squeezed by the cold expansion member.
[0013] Furthermore, the elastic member is an antifreeze plug, which is fixed in the shell base. The antifreeze plug is made of elastic material, and the liquid inlet channel is formed inside the antifreeze plug.
[0014] Beneficial effects: The antifreeze type urea pressure sensor with built-in heat conductive insert of the present invention has the following beneficial effects:
[0015] 1) There is an insert in the urea pressure sensor, which can conduct heat and make the heat dissipation performance of the pressure-sensitive element stronger. When the urea solution freezes, the heat dissipation of the urea solution close to the pressure-sensitive element will also be stronger, so that the urea solution close to the pressure-sensitive element will freeze first. As a result, the expansion force acting on the pressure-sensitive element when freezing will be smaller;
[0016] 2) There is a cold expansion component between the insert and the shell cover. When the temperature is low, the cold expansion component will freeze and expand before the pressure-sensitive element, squeeze open the gap between the shell cover and the shell base, and squeeze the insert to fit tightly against the pressure-sensitive element, thereby improving the heat conduction effect of the insert; when the temperature is high, the volume of the cold expansion component becomes smaller, and the insert is no longer close to the pressure-sensitive element, avoiding affecting the pressure measurement accuracy of the pressure-sensitive element. BRIEF DESCRIPTION OF THE DRAWINGS
[0017] Attached Figure 1 It is a schematic diagram of the internal structure of the urea pressure sensor of the present invention;
[0018] Attached Figure 2 Schematic diagram of the pre-cooling expansion piece between the insert and the shell cover. DETAILED DESCRIPTION
[0019] The present invention will be further described below in conjunction with the accompanying drawings.
[0020] As attached Figures 1 to 2 The antifreeze type urea pressure sensor with built-in heat conductive insert comprises a sensor housing 1, a liquid inlet channel 2 is arranged in the sensor housing 1, one end of the liquid inlet channel 2 is connected to the outside of the sensor housing 1, and a pressure sensing element 3 is arranged at the other end of the liquid inlet channel 2. The urea solution can flow along the liquid inlet channel 2 to the pressure sensing element 3. The pressure sensing element 3 can measure the pressure of the urea solution and feed it back to the SCR system in the vehicle to determine the injection amount of urea.
[0021] The volume of the urea solution is related to the temperature. Generally, when the ambient temperature is lower than -11°C, the urea solution freezes, causing the volume of the urea solution to expand by about 10%. Therefore, an elastic member is provided in the liquid inlet channel 2, and the elastic member can deform and shrink to adapt to the volume change of the urea solution, absorb the expansion force of the urea solution, and protect the pressure-sensitive element 3.
[0022] In the freezing process of the urea solution, if the side close to the liquid inlet channel 2 freezes first and the side close to the pressure-sensitive element 3 freezes later, then after the urea solution in the liquid inlet channel 2 freezes, the elastic member in the liquid inlet channel 2 can no longer absorb the expansion force. Therefore, under this freezing order, the pressure-sensitive element 3 may still be damaged by the expansion of the urea solution. Therefore, an insert 4 is also provided in the sensor housing 1. The insert 4 is made of a heat-conducting material. The insert 4 has an internal connection part and an external connection part. The internal connection part is connected to the pressure-sensitive element 3, and the external connection part is connected to the outside world, so that the pressure-sensitive element 3 can conduct heat to the outside world through the insert 4, thereby improving the heat dissipation performance of the pressure-sensitive element 3. Accordingly, the heat dissipation performance of the urea solution close to the side of the pressure-sensitive element 3 will also be correspondingly enhanced, so that the urea solution close to the side of the pressure-sensitive element 3 can freeze first. In this way, the elastic member can play a role in absorbing the expansion force during the entire freezing process, and the pressure-sensitive element 3 is not easily damaged by extrusion.
[0023] As attached Figure 1 As shown in the figure, the insert 4 is an annular structure, and the insert 4 is arranged around the outer periphery of the pressure-sensitive element 3. The inner wall of the insert 4 is the inner connecting part, and the inner wall of the insert 4 is connected to the side wall of the pressure-sensitive element 3, so that the pressure-sensitive element 3 can conduct heat to the inner wall of the insert 4.
[0024] The sensor housing 1 is composed of a shell base 5 at the bottom and a shell cover 6 at the top. There is a slit 12 between the shell base 5 and the shell cover 6. The outer wall of the insert 4 is the external connection part. Part of the outer wall of the insert 4 is exposed to the outside through the slit 12, so that the insert 4 can conduct heat to the outside through the slit 12.
[0025] As attached Figure 2As shown in , there is a bevel on the inner side of the lower edge of the shell cover 6, and there is also a bevel on the outer side of the upper edge of the shell base 5, and the lower edge of the shell cover 6 is separated from the upper edge of the shell base 5 by a gap, thereby forming an oblique slit 12 between the shell cover 6 and the shell base 5. There is a cold expansion member 8 between the insert 4 and the shell cover 6, and the cold expansion member 8 can expand at low temperatures. When the cold expansion member 8 expands, it will open the shell cover 6 outward, and because the slit 12 is oblique, the slit 12 between the shell cover 6 and the shell base 5 will expand, thereby increasing the heat exchange efficiency between the insert 4 and the outside world, and enhancing the ability of the insert 4 to conduct heat to the outside world. In addition, when the cold expansion member 8 expands, it will also squeeze the insert 4 inward. After the insert 4 is squeezed, the insert 4 will be closer to the pressure-sensitive element 3, so that the heat conduction capacity between the pressure-sensitive element 3 and the insert 4 is enhanced. In summary, after the expansion member 8 expands when exposed to cold, the ability of the insert 4 to conduct the heat of the pressure-sensitive element 3 to the outside is enhanced, so that the urea solution near the side of the pressure-sensitive element 3 freezes first.
[0026] When the temperature is high, the expansion member 8 does not expand when it is cold, and the volume of the expansion member 8 is small. At this time, the insert 4 does not squeeze the pressure-sensitive element 3, and the degree of close contact with the pressure-sensitive element 3 is low. When the pressure-sensitive element 3 measures the pressure of the urea solution, the insert 4 will not squeeze the pressure-sensitive element 3, which will cause an adverse effect, thereby reducing the pressure measurement accuracy of the pressure-sensitive element 3.
[0027] As attached Figure 2 As shown in the figure, an annular groove 7 is provided on the outer wall of the insert 4, and an annular space for accommodating the cold expansion member 8 is formed between the annular groove 7 and the inner wall of the shell cover 6, and the cold expansion member 8 is correspondingly placed in the annular groove 7. In one embodiment, the cold expansion member 8 includes an annular elastic capsule, and the elastic capsule is correspondingly placed in the annular groove 7. The elastic capsule has a cavity inside, and the cavity is filled with a cold expansion liquid, which can freeze and expand at low temperature. The elastic capsule is placed in the annular groove 7 in a compressed state. After the cold expansion liquid expands, the cold expansion liquid will open the elastic capsule, causing the elastic capsule to expand accordingly, and squeeze the shell cover 6 and the insert 4. The melting point of the cold expansion liquid is higher than the melting point of the urea solution, so that before the urea solution freezes, the cold expansion liquid has already frozen first, and opens the slit 12 and squeezes the insert 4. In a specific embodiment, the cold expansion liquid can be water.
[0028] As attached Figure 1As shown in , an inner bracket 9 is also provided in the sensor housing 1, and the lower end of the insert 4 is embedded in the shell base 5, so that the lower end of the insert 4 is fixedly connected to the shell base 5. The upper end of the insert 4 hooks the inner bracket 9, and the inner bracket 9 presses the pressure-sensitive element 3 into the shell base 5. The shell cover 6 covers the inner bracket 9 and is fixedly connected to the inner bracket 9. In one embodiment, the shell cover 6 is fixedly connected to the inner bracket 9 by locking screws. The insert 4 is arranged around the inner bracket 9, and the inner wall of the insert 4 is connected to the outer wall of the inner bracket 9. An inward-retracting notch 10 is provided on the inner bracket 9, and the inward-retracting notch 10 is opposite to the position of the cold expansion member 8. When the insert 4 is squeezed by the cold expansion member 8, the insert 4 can be deformed toward the inward-retracting notch 10, so that the insert 4 will not squeeze the pressure-sensitive element 3 too much, thereby protecting the pressure-sensitive element 3 from being damaged due to the squeezing of the insert 4.
[0029] The elastic member is an antifreeze plug 11 , which is fixed in the shell base 5 . The antifreeze plug 11 is made of elastic material. In one embodiment, the antifreeze plug 11 is made of EPDM, and the liquid inlet channel 2 is formed inside the antifreeze plug 11 .
[0030] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.
Claims
1. Antifreeze type urea pressure sensor with built-in thermal conductive insert, characterized in that: The sensor housing (1) comprises a liquid inlet channel (2) in the sensor housing (1), a pressure-sensitive element (3) at the end of the liquid inlet channel (2), and urea solution can flow along the liquid inlet channel (2) to the pressure-sensitive element (3); the volume of the urea solution is related to the temperature, an elastic member is arranged in the liquid inlet channel (2), and the elastic member can deform and shrink to adapt to the volume change of the urea solution; an insert (4) is also arranged in the sensor housing (1), the insert (4) is made of a heat-conducting material, and the insert (4) has an internal connection part and an external connection part, the internal connection part is connected to the pressure-sensitive element (3), and the external connection part is connected to the outside, so that the pressure-sensitive element (3) can transfer heat to the outside through the insert (4).
2. The antifreeze type urea pressure sensor with built-in thermal conductive insert according to claim 1, characterized in that: The insert (4) is arranged outside the pressure-sensitive element (3), the inner wall of the insert (4) is the inner connection part, and the inner wall of the insert (4) is connected to the side wall of the pressure-sensitive element (3).
3. The antifreeze type urea pressure sensor with built-in thermal conductive insert according to claim 2, characterized in that: The sensor housing (1) is composed of a housing base (5) and a housing cover (6); a slit (12) is provided between the housing base (5) and the housing cover (6); the outer wall of the insert (4) is the external connection portion; and a portion of the outer wall of the insert (4) is exposed to the outside through the slit (12).
4. The antifreeze type urea pressure sensor with built-in thermal conductive insert according to claim 3, characterized in that: The lower edge of the shell cover (6) has an inner bevel, and the upper edge of the shell base (5) has an outer bevel. The lower edge of the shell cover (6) and the upper edge of the shell base (5) are separated by a gap to form an oblique slit (12). A cold expansion member (8) is provided between the insert (4) and the shell cover (6). The cold expansion member (8) can expand at low temperatures, push the shell cover (6) outwards and press the insert (4) inwards, so that the slit (12) between the shell cover (6) and the shell base (5) expands, and the insert (4) is pressed and pressed against the pressure-sensitive element (3).
5. The antifreeze type urea pressure sensor with built-in thermal conductive insert according to claim 4, characterized in that: An annular groove (7) is provided on the outer wall of the insert (4), and an annular space for accommodating a cold expansion member (8) is formed between the annular groove (7) and the inner wall of the shell cover (6), and the cold expansion member (8) is correspondingly placed in the annular groove (7).
6. The antifreeze type urea pressure sensor with built-in thermal conductive insert according to claim 5, characterized in that: The cold expansion member (8) comprises an annular elastic sac, which is correspondingly placed in the annular groove (7); the elastic sac contains cold expansion liquid inside, and the cold expansion liquid can freeze and expand at low temperature.
7. The antifreeze type urea pressure sensor with built-in thermal conductive insert according to claim 6, characterized in that: The melting point of the cooled expansion liquid is higher than the melting point of the urea solution.
8. The antifreeze type urea pressure sensor with built-in thermal conductive insert according to claim 4, characterized in that: An inner bracket (9) is arranged in the sensor housing (1); the lower end of the insert (4) is embedded in the housing base (5); the upper end of the insert (4) hooks the inner bracket (9); the inner bracket (9) presses the pressure-sensitive element (3) into the housing base (5); and the housing cover (6) covers the inner bracket (9) and is fixedly connected to the inner bracket (9).
9. The antifreeze type urea pressure sensor with built-in thermal conductive insert according to claim 8, characterized in that: The insert (4) is arranged on the inner bracket (9), and the inner wall of the insert (4) is connected to the outer wall of the inner bracket (9); an inward-retracted notch (10) is provided on the inner bracket (9), and the inward-retracted notch (10) is opposite to the position of the cold expansion member (8), and the insert (4) can be deformed towards the inward-retracted notch (10) when squeezed by the cold expansion member (8).
10. The antifreeze type urea pressure sensor with built-in thermal conductive insert according to any one of claims 3 to 9, characterized in that: The elastic member is an antifreeze plug (11), the antifreeze plug (11) is fixed in the shell base (5), the antifreeze plug (11) is made of elastic material, and the interior of the antifreeze plug (11) forms the liquid inlet channel (2).