CN207923238U - A kind of liquid level detection device of automobile cooling - Google Patents
A kind of liquid level detection device of automobile cooling Download PDFInfo
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- CN207923238U CN207923238U CN201820522663.3U CN201820522663U CN207923238U CN 207923238 U CN207923238 U CN 207923238U CN 201820522663 U CN201820522663 U CN 201820522663U CN 207923238 U CN207923238 U CN 207923238U
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Abstract
A kind of liquid level detection device of automobile cooling, belongs to technical field of automotive electronics, solves the problems, such as that the reliability of the testing result of the liquid level detection device of existing automobile cooling is relatively low.Liquid level detection device：The first end of resistance R1 is connected with PWM signal generator P, and the second end of resistance R1 is connected with the base stage B of the first end of resistance R2 and triode simultaneously.The second end of resistance R2 and the emitter E of triode are grounded.The first end of the collector C and capacitance C1 of triode are connected through resistance R3 with voltage source VCC.The second end of capacitance C1 is connected with the cathode of the first end of resistance R4 and diode D2 simultaneously, the second end of resistance R4 is connected with the anode of diode D1, the cathode of diode D1 and the anode of diode D2 are connected with level sensing unit LT, the second end of resistance R4 and the common end of the anode of diode D1 are liquid level feedback signal output end, and triode is NPN type triode.
Description
Technical field
The utility model is related to a kind of liquid level detection devices, belong to technical field of automotive electronics.
Background technology
In order to ensure automobile engine can operate at normal working temperature, need to the liquid level of automobile cooling into
Row detection in real time, leads to the water temperature over-high of automobile engine, automotive system machine to avoid because the liquid level of automobile cooling is too low
Part damages.
The liquid level detection device of existing automobile cooling is all made of liquid level sensor as detecting element.Liquid level sensor is close
It is seemingly equivalent to capacitance resistance ware, normal under too low two states in the liquid level of automobile cooling, impedance has apparent difference.
The liquid level detection device of existing automobile cooling is using detection circuit and liquid level sensor cooperating.Existing inspection
Slowdown monitoring circuit is usually made of divider resistance, RC low-pass filter circuits and clamping protective circuit etc..Under conditions of working long hours,
With the liquid level sensor of this detection circuit cooperating, the feelings that impedance parameter can be constant in the fluid level condition of automobile cooling
It changes under condition, and then influences the reliability of the testing result of the liquid level detection device of existing automobile cooling.
Utility model content
The utility model is that the reliability of the testing result for the liquid level detection device for solving existing automobile cooling is lower
A kind of problem, it is proposed that liquid level detection device of automobile cooling.
The liquid level detection device of automobile cooling described in the utility model includes detection circuit and level sensing unit LT；
Detection circuit includes PWM signal generator P, resistance R1, resistance R2, resistance R3, resistance R4, capacitance C1, diode
D1, diode D2, triode and voltage source VCC；
Triode is NPN type triode；
The pwm signal output end of PWM signal generator P is connected with the first end of resistance R1, and the second end of resistance R1 is simultaneously
It is connected with the base stage B of the first end of resistance R2 and triode, the second end of resistance R2 and the emitter E of triode are and power ground
Be connected, the collector C of triode is connected with the first end of the first end of resistance R3 and capacitance C1 simultaneously, the second end of resistance R3 and
Voltage source VCC is connected；
The second end of capacitance C1 is connected with the cathode of the first end of resistance R4 and diode D2 simultaneously, the second end of resistance R4
It is connected with the anode of diode D1, the cathode of diode D1 and the anode of diode D2 are connected with level sensing unit LT；
The common end of the second end of resistance R4 and the anode of diode D1 is liquid level feedback signal output end.
As preferably, level sensing unit LT is liquid level sensor.
As preferably, triode uses the triode of model MMBT5551.
The operation principle of the liquid level detection device of automobile cooling described in the utility model is：
PWM signal generator P, resistance R1, resistance R2, resistance R3, triode and voltage source VCC constitute square-wave signal and generate
Unit, for exporting direct current square-wave signal；
The direct current square-wave signal that square-wave signal generation unit is sent is converted to AC signal by capacitance C1, the AC signal according to
It is secondary to access level sensing unit LT through resistance R4 and diode D1；
When AC signal is in high level, level sensing unit LT obtains electric, and level sensing unit LT is to automobile cooling
Liquid level be detected；
When AC signal is in low level, level sensing unit LT completes level sensing, on level sensing unit LT
Pressure drop is released via diode D2, resistance R4 and diode the D1 series loop constituted；
The common end of the second end of resistance R4 and the anode of diode D1 is liquid level feedback signal output end, liquid level feedback letter
Number output end is connected with external detecting signal unit；
Detecting signal unit is used to detect the amplitude of liquid level feedback signal, when liquid level feedback signal is high level, shows
Automobile cooling is in low liquid level state；When liquid level feedback signal is low level, show that automobile cooling is in normal level
State.
Compared with the liquid level detection device of existing automobile cooling, the liquid level of automobile cooling described in the utility model is examined
The detection circuit for surveying device carries out noncontinuity power supply to level sensing unit LT.The common end of triode and resistance R3 are direct current
Direct current square-wave signal is converted to AC signal by square-wave signal output end, capacitance C1, and using the AC signal as level sensing
The detection signal of unit LT.Level sensing unit LT is detected the liquid level of automobile cooling according to the detection signal.Complete
After one-time detection, the bleed-off circuit of diode D2, resistance R4 and the pressure drop on diode D1 composition level sensing units LT, with
Ensure that the working condition of level sensing unit LT is synchronous with detection signal.This design concept not only increases existing automobile cooling
The accuracy and reliability of the testing result of the liquid level detection device of liquid, and extend the use longevity of level sensing unit LT
Life.
Description of the drawings
The liquid level inspection to automobile cooling described in the utility model will hereinafter be carried out based on the embodiments and with reference to the accompanying drawings
Device is surveyed to be described in more detail, wherein：
Fig. 1 is the circuit diagram of the liquid level detection device of the automobile cooling described in embodiment；
When Fig. 2 is that the automobile cooling that embodiment refers to is changed into low liquid level state from normal level state, recovery time
With the corresponding data figure of 3 voltage value of node.
Specific implementation mode
The liquid level detection device of automobile cooling described in the utility model is further illustrated below in conjunction with attached drawing.
Embodiment：The present embodiment is explained in detail with reference to Fig. 1 and Fig. 2.
The liquid level detection device of automobile cooling described in the present embodiment includes detection circuit and level sensing unit LT；
Detection circuit includes PWM signal generator P, resistance R1, resistance R2, resistance R3, resistance R4, capacitance C1, diode
D1, diode D2, triode and voltage source VCC；
Triode is NPN type triode；
The pwm signal output end of PWM signal generator P is connected with the first end of resistance R1, and the second end of resistance R1 is simultaneously
It is connected with the base stage B of the first end of resistance R2 and triode, the second end of resistance R2 and the emitter E of triode are and power ground
Be connected, the collector C of triode is connected with the first end of the first end of resistance R3 and capacitance C1 simultaneously, the second end of resistance R3 and
Voltage source VCC is connected；
The second end of capacitance C1 is connected with the cathode of the first end of resistance R4 and diode D2 simultaneously, the second end of resistance R4
It is connected with the anode of diode D1, the cathode of diode D1 and the anode of diode D2 are connected with level sensing unit LT；
The common end of the second end of resistance R4 and the anode of diode D1 is liquid level feedback signal output end.
The level sensing unit LT of the present embodiment is realized using liquid level sensor.In Fig. 1, liquid level sensor is equivalent to
Resistance C2 and resistance R5 in parallel.
The capacitance C1 of the present embodiment filters out the DC component in direct current square-wave signal using capacity coupled mode, is allowed into
For AC signal.The AC signal is successively through resistance R4 and diode D1 access level sensing units LT.Resistance R4 and diode
Detecting signal unit is accessed in the common end of D1, i.e. node 3.
The voltage drainage function of the liquid level detection device of automobile cooling described in the present embodiment mainly by diode D2 Lai
It realizes, when level sensing unit LT completes one-time detection, diode D2 conductings, and then realize releasing for pressure drop.
The resistance R4, diode D1 and diode D2 of the present embodiment can also constitute circuit protection unit.Work as external voltage
When excessively high, diode D1 cut-offs, place branch disconnects, and diode D2 conductings, place branch conducting, electric current is successively through two poles
Pipe D2 and resistance R4 flow into detecting signal unit.As long as the electric current of branch where ensureing diode D2 is less than 5mA and can reach guarantor
The purpose of shield.
The parameter or model of the electrical equipment of the liquid level detection device of automobile cooling described in the present embodiment are as follows：
The model of R1=4K7, R2=4K7, R3=2K, R4=75K, C1=0.47uF, D1 and D2 are M7, triode
The rated output voltage of model MMBT5551, VCC are 12V.
Illustrate the inspection of the liquid level detection device of the automobile cooling described in the present embodiment with reference to specific experiment data
Survey process：
The detection process when liquid level of automobile cooling is normal：PWM signal generator P drives triode, obtains high level
The direct current square-wave signal for being 0V for 12V, low level, the i.e. signal of node 1, detection time 4ms, detection cycle 43ms.Directly
It flows square-wave signal to couple through capacitance C1, obtains ac square wave signal, the i.e. signal of node 2, compared with direct current square-wave signal, exchange
The amplitude of square-wave signal translates downwards 1V.Ac square wave signal accesses level sensing unit LT through resistance R4 and diode D1, obtains
To node 3 signal of liquid level when normal.When detecting, the amplitude of 3 signal of node is 0.8V, when stopping detection, 3 signal of node
Amplitude is -0.4V.Due to the effect of diode D1, the detection voltage of node 4 is 0.4V (low level is effective), stops detection voltage
For 0V.Detect complete when, diode D2 starts to work, since the current potential of node 2 at this time is negative value, on level sensing unit LT
Pressure drop can release to 0V.
The detection process when liquid level of automobile cooling is too low：PWM signal generator P drives triode, obtains high level
The direct current square-wave signal for being 0V for 12V, low level, the i.e. signal of node 1, detection time 4ms, detection cycle 43ms.Directly
It flows square-wave signal to couple through capacitance C1, obtains ac square wave signal, the i.e. signal of node 2, compared with direct current square-wave signal, exchange
The amplitude of square-wave signal translates downwards 1V.Ac square wave signal accesses level sensing unit LT through resistance R4 and diode D1, obtains
To node 3 signal of liquid level when too low.When detecting, the amplitude of 3 signal of node is 8.2V, when stopping detection, 3 signal of node
Amplitude is -0.4V.Due to the effect of diode D1, the detection voltage of node 4 is 7.8V (high level is effective), stops detection voltage
For 0V.Detect complete when, diode D2 starts to work, since the current potential of node 2 at this time is negative value, on level sensing unit LT
Pressure drop can release to 0V.
Detection time when fluid level condition is converted：When automobile cooling is changed into low liquid level state from normal level state
When, detection time is 5s or so.When Back Up, required time is shorter, and moment can be completed.Fig. 2 is automobile cooling from just
When normal fluid level condition is changed into low liquid level state, the corresponding data figure of recovery time and 3 voltage value of node.In Fig. 2, at one group pair
In the data answered, the former is recovery time, and the latter is 3 voltage value of node.As shown in Fig. 2, the automobile cooling described in the present embodiment
The response speed of the liquid level detection device of liquid is very fast, and testing result is guaranteed.
The control principle of the liquid level detection device of automobile cooling described in the present embodiment, detection circuit is simple, response
Speed is fast, can not only extend the service life of level sensing unit LT, and can improve the stability of application system.
Although describing the utility model herein with reference to specific embodiment, it should be understood that, this
A little embodiments are only the principles of the present invention and the example of application.It should therefore be understood that can be to illustratively implementing
Example carries out many modifications, and can be designed that other arrangements, without departing from this practicality as defined in the appended claims
Novel spirit and scope.It should be understood that can be combined not by being different from mode described in original claim
Same dependent claims and feature described herein.It will also be appreciated that the feature in conjunction with described in separate embodiments
It can use in other embodiments.
Claims (3)
1. a kind of liquid level detection device of automobile cooling, which is characterized in that the liquid level detection device include detection circuit and
Level sensing unit LT；
Detection circuit includes PWM signal generator P, resistance R1, resistance R2, resistance R3, resistance R4, capacitance C1, diode D1, two
Pole pipe D2, triode and voltage source VCC；
Triode is NPN type triode；
The pwm signal output end of PWM signal generator P is connected with the first end of resistance R1, the second end of resistance R1 simultaneously with electricity
The first end of resistance R2 is connected with the base stage B of triode, the second end of resistance R2 and the emitter E of triode with power ground phase
Even, the collector C of triode is connected with the first end of the first end of resistance R3 and capacitance C1 simultaneously, second end and the electricity of resistance R3
Potential source VCC is connected；
The second end of capacitance C1 is connected with the cathode of the first end of resistance R4 and diode D2 simultaneously, the second end of resistance R4 and two
The anode of pole pipe D1 is connected, and the cathode of diode D1 and the anode of diode D2 are connected with level sensing unit LT；
The common end of the second end of resistance R4 and the anode of diode D1 is liquid level feedback signal output end.
2. the liquid level detection device of automobile cooling as described in claim 1, which is characterized in that level sensing unit LT is liquid
Level sensor.
3. the liquid level detection device of automobile cooling as claimed in claim 2, which is characterized in that triode uses model
The triode of MMBT5551.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201820522663.3U CN207923238U (en) | 2018-04-11 | 2018-04-11 | A kind of liquid level detection device of automobile cooling |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201820522663.3U CN207923238U (en) | 2018-04-11 | 2018-04-11 | A kind of liquid level detection device of automobile cooling |
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| CN207923238U true CN207923238U (en) | 2018-09-28 |
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| CN201820522663.3U Active CN207923238U (en) | 2018-04-11 | 2018-04-11 | A kind of liquid level detection device of automobile cooling |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108489573A (en) * | 2018-04-11 | 2018-09-04 | 航天科技控股集团股份有限公司 | A kind of liquid level detection device of automobile cooling |
| CN110346015A (en) * | 2019-08-05 | 2019-10-18 | 杭州微联智控科技有限公司 | Electric pole type water logging detection circuit and water sensor |
-
2018
- 2018-04-11 CN CN201820522663.3U patent/CN207923238U/en active Active
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108489573A (en) * | 2018-04-11 | 2018-09-04 | 航天科技控股集团股份有限公司 | A kind of liquid level detection device of automobile cooling |
| CN110346015A (en) * | 2019-08-05 | 2019-10-18 | 杭州微联智控科技有限公司 | Electric pole type water logging detection circuit and water sensor |
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