Negative pressure sensor for monitoring blockage condition of air filter

Abstract

The utility model provides a negative pressure sensor for monitoring the blocking condition of an air filter, and aims to improve the performance and reliability of an engine. The sensor adopts a diffused silicon chip as a pressure acquisition chip, has high measurement precision and micro-pressure measurement capability, and can monitor negative pressure change in the filter in real time. The measurement range of the sensor is-100 mbar to 0 mbar, an output voltage signal and the negative pressure of the air filter change linearly, and the voltage range is 4.875 V to 0.5 V. And through the high-precision amplification chip, the sensor amplifies a millivolt-level signal into a standard signal and outputs the standard signal, so that the anti-interference capability of signal transmission is enhanced. The vehicle-mounted ECU can detect the blocking condition of the filter in real time and detect whether the sensor is damaged or not. The sensor is simple in structure and convenient to install, can timely inform a driver to replace the filter, prevents an engine from being damaged, and has important practical value.

Description

Technical Field

[0001] The utility model relates to the technical field of sensors, in particular to a negative pressure sensor for monitoring the clogging condition of an air filter. Background Technique

[0002] The air filter is a key component in the engine system, and its main function is to filter the air entering the engine to prevent impurities and moisture from entering. During use, the air filter will gradually become clogged due to the accumulation of impurities, which affects the engine performance and may even cause engine damage in severe cases. In order to monitor the clogging condition of the filter and replace the filter in time to avoid engine damage caused by complete clogging of the filter, it is particularly necessary to monitor the clogging condition of the filter.

[0003] Such as Figure 1 shown (the key numbers in the figure are: 1 - negative pressure pipeline with the cavity communicating with the filter, 2 - installation thread, 3 - adjusting nut, 4 - spring, 5 - silicone diaphragm, 6 - metal top cap, 7 - microswitch contact, 8 - microswitch, 9 - pin, 10 - cubic cushion block, 11 - connector), the prior art usually adopts a mechanical negative pressure sensor. The tail of this negative pressure sensor makes its 1 inner cavity communicate with the filter negative pressure pipeline through 2 threaded interfaces. The spring 4 is compressed by the adjusting nut 3 and presses against the silicone diaphragm 5. The metal top cap 6 riveted on the diaphragm presses the microswitch contact 7 into the microswitch 8, making the originally normally closed switch open; the set alarm pressure value is generally set to about -62 mbar. When the negative pressure in the filter reaches this value and offsets the pressure value of the spring on the diaphragm, the contact on the diaphragm disengages from the contact of the microswitch, and the microswitch resets, and the switch returns to the normally closed state. The two normally closed pins of the microswitch are respectively welded to the pins 9 of the connector. The connector 11 is inserted into the external mating connector to connect it to the external circuit, thereby turning on the external alarm circuit.

[0004] However, the above negative pressure alarm sensor cannot directly detect the real-time change process of the filter negative pressure. The vehicle-mounted ECU cannot detect the real-time clogging condition of the filter, and it cannot be detected if the negative pressure alarm is damaged. After long-term use, the filter will be severely clogged, resulting in the engine being unable to start or even engine damage. Content of the Utility Model

[0005] The purpose of the utility model is to provide a negative pressure sensor for monitoring the clogging condition of an air filter to solve the problems raised in the above background technique:

[0006] (1) How to be able to monitor the clogging condition of the air filter in real time to improve the reliability and safety of the engine.

[0007] To achieve the above purpose, the utility model provides the following technical solutions:

[0008] A negative pressure sensor for monitoring the clogging condition of an air filter;

[0009] It at least includes a chip component. The chip component includes a PCB circuit board and an output interface. A diffused silicon chip and an amplification circuit are provided on the PCB circuit board. The diffused silicon chip is used to collect the pressure change inside the filter, and the amplification circuit is used to amplify the millivolt-level signal collected by the diffused silicon chip into a standard signal. The output interface is used to output the amplified signal to the vehicle-mounted ECU.

[0010] Based on the above technical solution, the present utility model can also be improved as follows.

[0011] Further, the output interface adopts a plurality of connector electrodes.

[0012] Further, the chip component further includes a chip housing. A monitoring notch is opened on the upper end face of the chip housing. The PCB circuit board is fixed between the upper end face of the chip housing. A first through hole communicating with the monitoring notch is opened on the lower end face of the chip housing.

[0013] Further, it also includes a socket and a lower housing. A plugging notch is opened on the upper side end face of the socket. The output interface of the chip component is installed in the plugging notch of the socket. The socket and the lower housing are matched and the socket and the lower housing form a stepped assembly chamber. The chip component is fixedly installed in the assembly chamber;

[0014] A second through hole communicating with the assembly chamber is opened at the bottom of the plugging notch of the socket, and a third through hole communicating with the assembly chamber is also opened on the lower end face of the lower housing.

[0015] Further, a waterproof and breathable film completely covering the second through hole is attached to the side wall of the assembly chamber; similarly, a waterproof and breathable film completely covering the first through hole is also attached to the bottom wall of the monitoring notch.

[0016] Further, a first sealing ring is provided on the mating end face between the socket and the lower housing; a second sealing ring is provided between the chip housing of the chip component and the socket; a third sealing ring is also provided between the chip housing of the chip component and the PCB circuit board.

[0017] Further, the voltage signal output by the sensor changes linearly with the negative pressure of the air filter, and the voltage range is from 4.875V to 0.5V.

[0018] Further, the measurement range of the diffused silicon chip is from -100 mbar to 0 mbar.

[0019] After adopting such a structure, the negative pressure sensor for monitoring the clogging condition of the air filter is connected to the air filter through a threaded interface. When the inside of the filter is clogged, causing the negative pressure inside it to increase and reach the set value, the in-vehicle ECU determines that the filter is severely clogged through this signal and sends a signal to notify the driver to replace the filter.

[0020] The beneficial technical effects of the negative pressure sensor for monitoring the clogging condition of the air filter are as follows:

[0021] (1). The pressure sensor of the present utility model uses a diffused silicon chip as the chip for collecting the pressure of the filter. By using diffused silicon lithography, silicon with the same resistance value is formed into a Wheatstone bridge to detect the change in the resistance value of the silicon strip in the bridge circuit caused by the pressure on the silicon bridge substrate, which causes the bridge circuit to lose balance and thus outputs a tiny voltage value. This voltage value is then amplified by the post-stage circuit and amplified into a standard signal for output. The clogging condition of the filter can be detected through this micro-strain, and the clogging condition of the filter can be monitored in real time.

[0022] (2). High measurement accuracy, capable of measuring micro-pressure: pressures from -100 mbar to 0 mbar.

[0023] (3). The output voltage value of the pressure signal changes with the clogging degree, and the pressure signal reflected by the sensor changes linearly. The in-vehicle ECU can detect the clogging condition inside the filter in real time, and at the same time, the in-vehicle ECU can also detect whether the sensor is damaged. Description of the Drawings

[0024] Figure 1 is a cross-sectional view of the structural schematic diagram of a mechanical negative pressure sensor in the prior art.

[0025] Figure 2 is a top view of an embodiment of the negative pressure sensor for monitoring the clogging condition of the air filter.

[0026] Figure 3 is Figure 2 a cross-sectional view along the A-A direction.

[0027] Figure 4 is one of the perspective views of an embodiment of the negative pressure sensor for monitoring the clogging condition of the air filter.

[0028] Figure 5 is one of the perspective views of an embodiment of the negative pressure sensor for monitoring the clogging condition of the air filter.

[0029] Figure 6 is a cross-sectional view of the schematic diagram of the chip assembly in an embodiment of the negative pressure sensor for monitoring the clogging condition of the air filter.

[0030] Explanation of the reference numerals in the figures:

[0031] Chip housing - 110; Monitoring notch - 111; First perforation - 112; First waterproof and breathable membrane - 113; Connector electrode - 120; PCB circuit board - 130; Socket - 200; Threaded interface tube body - 210; Plug housing - 220; Plugging slot - 211; Second perforation - 221; Second waterproof and breathable membrane - 222; Lower housing - 300; Third perforation - 310; Assembly chamber - 400; First sealing ring - 510; Second sealing ring - 520; Third sealing ring - 530. Detailed implementation mode

[0032] To make the above - mentioned objects, features and advantages of the present utility model more obvious and understandable, the following detailed description of the specific implementation mode of the present utility model will be given in conjunction with the accompanying drawings. Many specific details are set forth in the following description in order to fully understand the present utility model. However, the present utility model can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without departing from the connotation of the present utility model. Therefore, the present utility model is not limited by the specific implementations disclosed below.

[0033] The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are for illustrative purposes only and do not represent the only implementation mode.

[0034] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which the present utility model belongs. The terms used herein in the specification of the present utility model are only for the purpose of describing specific embodiments and are not intended to limit the present utility model. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0035] Please refer to Figures 2 to 6 。

[0036] The negative - pressure sensor for monitoring the clogging condition of the air filter includes a chip assembly, a socket 200 and a lower housing 300.

[0037] The chip assembly is located at the central part of the negative - pressure sensor. The chip assembly includes a chip housing 110, a PCB circuit board 130 and an output interface. A diffused - silicon chip and an amplification circuit are provided on the PCB circuit board 130. The diffused - silicon chip is used to collect the pressure change in the filter, and the amplification circuit is used to amplify the millivolt - level signal collected by the diffused - silicon chip into a standard signal. The output interface is used to output the amplified signal to the vehicle - mounted ECU, and the output interface uses a number of connector electrodes 120.

[0038] A diffused silicon chip is used as the chip for collecting the pressure of the filter. By using diffused silicon lithography, silicon with the same resistance value is formed into a Wheatstone bridge to detect the change in the resistance value of the silicon strip in the bridge circuit caused by the pressure on the silicon bridge substrate, which makes the bridge circuit lose balance and thus outputs a tiny voltage value. This voltage value is then amplified by the subsequent circuit and amplified into a standard signal for output. The clogging situation of the filter can be detected through this microstrain, and the clogging situation of the filter can be monitored in real time. The amplification circuit amplifies the millivolt-level signal into a standard signal for output, enhancing the anti-interference ability of signal transmission. The voltage signal output by the sensor changes with the change of the negative pressure in the filter, and the clogging situation of the filter is monitored in real time.

[0039] Due to the high measurement accuracy and micro-pressure measurement ability of the diffused silicon chip, the measurement range is from -100 mbar to 0 mbar. The voltage signal output by the sensor changes linearly with the negative pressure of the air filter, and the voltage range is from 4.875 V to 0.5 V, and the accuracy in the full temperature range can reach ±0.1 V.

[0040] A monitoring notch 111 is opened on the upper end surface of the chip housing 110. The PCB circuit board 130 is fixed between the upper end surface of the chip housing 110. The diffused silicon chip on the PCB circuit board 130 is aligned with the monitoring notch 111 of the chip housing 110. A first through hole 112 communicating with the monitoring notch 111 is opened on the lower end surface of the chip housing 110. A first waterproof and breathable membrane 113 that completely covers the first through hole 112 is attached to the bottom wall of the monitoring notch 111.

[0041] The socket 200 includes a threaded interface tube body 210 on the upper side and a plug-in housing 220 on the lower side. An insertion slot 211 is formed in the inner hole of the threaded interface tube body 210 of the socket 200. The plug-in electrode 120 of the chip assembly is installed in the insertion slot 211 of the socket 200. The socket 200 and the lower housing 300 are fixed together by a self-tapping screw 3 of M5*12, and the socket 200 and the lower housing 300 form a stepped assembly chamber 400. The chip housing 110 of the chip assembly is fixedly installed in the assembly chamber 400 by bolts. A second through hole 221 communicating with the assembly chamber 400 is opened at the bottom of the insertion slot 211 of the socket 200. A second waterproof and breathable membrane 222 that completely covers the second through hole 221 is attached to the side wall of the assembly chamber 400. A third through hole 310 communicating with the assembly chamber 400 is also opened on the lower end surface of the lower housing 300. The third through hole 310 of the lower housing 300 communicates with the first through hole 112 of the chip housing 110.

[0042] A first sealing ring 510 is provided on the mating end face between the receptacle 200 and the lower housing 300, and the first sealing ring 510 is an "O" - shaped sealing ring with a D20*1 specification; a second sealing ring 520 is provided between the chip housing 110 of the chip assembly and the receptacle 200; a third sealing ring 530 is further provided between the chip housing 110 of the chip assembly and the PCB circuit board 130, and both the second sealing ring 520 and the third sealing ring 530 are "O" - shaped sealing rings with a D21*1 specification.

[0043] During use, this negative - pressure sensor is connected to the screw on the air filter through the NPT1 / 8 thread inside the lower housing 300. The third perforation 310 of the lower housing 300 communicates with the pipeline at the rear end of the filter. When the inside of the filter is blocked, resulting in an increase in the negative pressure inside it and reaching the set value, the vehicle - mounted ECU determines that the filter is severely blocked through this signal and sends a signal to notify the driver to replace the filter.

[0044] The above - mentioned is only one implementation manner of the present utility model. It should be pointed out that for those of ordinary skill in the art, without departing from the principle of the present utility model, several variations and improvements can be made, and these should also be regarded as belonging to the protection scope of the present utility model.

Claims

1. A negative pressure sensor for monitoring the clogging condition of an air filter, characterized in that: It at least includes a chip component, and the chip component includes a PCB circuit board (130) and an output interface. A diffused silicon chip and an amplification circuit are provided on the PCB circuit board (130). The diffused silicon chip is used to collect the pressure change in the filter, and the amplification circuit is used to amplify the millivolt-level signal collected by the diffused silicon chip into a standard signal. The output interface is used to output the amplified signal to the vehicle-mounted ECU.

2. The negative pressure sensor for monitoring the clogging condition of the air filter according to claim 1, wherein: The output interface adopts a plurality of connector electrodes (120).

3. The negative pressure sensor for monitoring the clogging condition of an air filter according to claim 1, characterized in that: The chip component further includes a chip housing (110). A monitoring notch (111) is opened on the upper end face of the chip housing (110). The PCB circuit board (130) is fixed to the upper end face of the chip housing (110). A first through hole (112) communicating with the monitoring notch (111) is opened on the lower end face of the chip housing (110).

4. The negative pressure sensor for monitoring the clogging condition of an air filter according to claim 3, characterized in that: It further includes a socket (200) and a lower housing (300). A plugging slot (211) is opened on the upper side end face of the socket (200). The output interface of the chip component is installed in the plugging slot (211) of the socket (200). The socket (200) and the lower housing (300) are matched and the socket (200) and the lower housing (300) form a stepped assembly chamber (400). The chip component is fixedly installed in the assembly chamber (400); A second through hole (221) communicating with the assembly chamber (400) is opened at the bottom of the plugging slot (211) of the socket (200), and a third through hole (310) communicating with the assembly chamber (400) is also opened on the lower end face of the lower housing (300).

5. The negative pressure sensor for monitoring the clogging condition of an air filter according to claim 4, characterized in that: A waterproof and breathable film completely covering the second through hole (221) is attached to the side wall of the assembly chamber (400); similarly, a waterproof and breathable film completely covering the first through hole (112) is also attached to the bottom wall of the monitoring notch (111).

6. The negative pressure sensor for monitoring the clogging condition of an air filter according to claim 5, characterized in that: Connect A first sealing ring (510) is provided on the mating end face between the socket (200) and the lower housing (300); a second sealing ring (520) is provided between the chip housing (110) of the chip component and the socket (200); a third sealing ring (530) is further provided between the chip housing (110) of the chip component and the PCB circuit board (130).

7. The negative pressure sensor for monitoring the clogging condition of an air filter according to claim 1, characterized in that: The voltage signal output by the sensor changes linearly with the negative pressure of the air filter, and the voltage range is from 4.875V to 0.5V.

8. The negative pressure sensor for monitoring the clogging condition of an air filter according to claim 1, characterized in that: The measurement range of the diffused silicon chip is from -100 mbar to 0 mbar.

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