CN201508209U - Capacitance electronic fuel sensor - Google Patents
Capacitance electronic fuel sensor Download PDFInfo
- Publication number
- CN201508209U CN201508209U CN2009201515207U CN200920151520U CN201508209U CN 201508209 U CN201508209 U CN 201508209U CN 2009201515207 U CN2009201515207 U CN 2009201515207U CN 200920151520 U CN200920151520 U CN 200920151520U CN 201508209 U CN201508209 U CN 201508209U
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- CN
- China
- Prior art keywords
- capacitance
- unit
- liquid level
- sensor
- control module
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
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- 239000000446 fuel Substances 0.000 title claims abstract description 51
- 239000007788 liquid Substances 0.000 claims abstract description 29
- 238000005259 measurement Methods 0.000 claims abstract description 27
- 229910052751 metal Inorganic materials 0.000 claims abstract description 24
- 239000002184 metal Substances 0.000 claims abstract description 24
- 239000003990 capacitor Substances 0.000 claims abstract description 19
- 238000012545 processing Methods 0.000 claims description 19
- 238000004891 communication Methods 0.000 claims description 11
- 238000006243 chemical reaction Methods 0.000 abstract description 4
- 238000004519 manufacturing process Methods 0.000 abstract 1
- 239000000295 fuel oil Substances 0.000 description 5
- 238000000034 method Methods 0.000 description 3
- 229910052782 aluminium Inorganic materials 0.000 description 2
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 2
- 230000008901 benefit Effects 0.000 description 2
- 230000008859 change Effects 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 239000002828 fuel tank Substances 0.000 description 2
- 230000001939 inductive effect Effects 0.000 description 2
- 238000009434 installation Methods 0.000 description 2
- 239000011810 insulating material Substances 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 238000005192 partition Methods 0.000 description 2
- 230000008569 process Effects 0.000 description 2
- 230000009466 transformation Effects 0.000 description 2
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- 239000004809 Teflon Substances 0.000 description 1
- 229920006362 Teflon® Polymers 0.000 description 1
- 230000032683 aging Effects 0.000 description 1
- 239000004411 aluminium Substances 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 238000004364 calculation method Methods 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 239000010949 copper Substances 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 238000009413 insulation Methods 0.000 description 1
- 238000002955 isolation Methods 0.000 description 1
- 230000007774 longterm Effects 0.000 description 1
- 239000007769 metal material Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 239000003921 oil Substances 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 229920001343 polytetrafluoroethylene Polymers 0.000 description 1
- 239000004810 polytetrafluoroethylene Substances 0.000 description 1
- 238000005507 spraying Methods 0.000 description 1
- 239000010935 stainless steel Substances 0.000 description 1
- 229910001220 stainless steel Inorganic materials 0.000 description 1
- 230000001360 synchronised effect Effects 0.000 description 1
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- Measurement Of Levels Of Liquids Or Fluent Solid Materials (AREA)
Abstract
The utility model discloses a capacitance electronic fuel sensor, comprising a capacitance sensor unit, a capacitance measuring unit and a capacitance/liquid level conversion unit, wherein the capacitance sensor unit is a combination tubular capacitance element which comprises a metal outer tube and a metal inner tube; the metal outer tube and the metal inner tube form a fuel liquid level sensor capacitor; the capacitance sensor unit is used for converting the fuel liquid level to a corresponding capacitance value; the metal outer tube and the metal inner tube of the capacitance sensor unit are connected with the input end of the capacitance measuring unit respectively through lead wires; the capacitance measuring unit is used for measuring the capacitance value of the capacitance sensor unit; and the capacitance/liquid level conversion unit is electrically connected with the capacitance measuring unit and used for converting the capacitance value from the capacitance measuring unit to the liquid level. The capacitance electronic fuel sensor has simple structure and easy manufacturing, and solves the common problems of excessive distributed parameters and difficult accurate measurement of capacitance parameters in the capacitance fuel sensor.
Description
Technical field
The utility model relates to a kind of fuel sensor, relates in particular to a kind of capacitance electronic type fuel sensor.
Background technology
In vehicle fuel sensor market, fuel sensor mainly contains magnetic red rheostat fuel sensor, the sliding rheostat fuel sensor, four kinds of condenser type fuel sensor and pressure type fuel sensors, what the home market occupation rate was the highest is swing arm and tongue tube fuel sensor.The condenser type fuel sensor has caused widely with its precision height, good temp characteristic, the advantage that is easy to make to be paid close attention to, and in the condenser type fuel sensor, using maximum is to become medium type capacitance type sensor, and its product realization at present mainly contains following difficult point:
1, be subject to distribution parameter influence, capacitance type sensor be measured as capacitance, so product is subjected to effects of distribution parameters easily, thereby cause the error of measurement;
2, capacitance parameter is difficult for accurately measuring.
Summary of the invention
The purpose of this utility model is to provide a kind of simple and capacitance electronic type fuel sensor of being easy to make, it is excessive to solve distribution parameter common in the condenser type fuel sensor, capacitance parameter is difficult for the accurately problem of measurement, and capacitance measurement circuit and algorithm that capacitance electronic type fuel sensor described in the utility model adopts can effectively reduce the error of measured capacitance value.
In order to achieve the above object, the utility model provides a kind of capacitance electronic type fuel sensor, and it comprises capacitance sensing unit and capacitance measurement unit and electric capacity/liquid level converting unit, wherein,
Described capacitance sensing unit is the assembled tube type capacity cell, comprises metal outer pipe and metal inner pipe, and described metal outer pipe and described metal inner pipe constitute the fuel liquid level sensor capacitor; Described capacitance sensing unit is used for fuel liquid level is converted to relevant capacitance value;
The metal outer pipe of described capacitance sensing unit and metal inner pipe are connected to the input end of described capacitance measurement unit respectively by lead-in wire;
Described capacitance measurement unit is used to measure the capacitance of described capacitance sensor unit;
Described electric capacity/liquid level converting unit is electrically connected with described capacitance measurement unit, is used for the capacitance from described capacitance measurement unit is converted to liquid level.
Preferably, described capacitance measurement unit comprises processing module, control module and power module, wherein,
Described power module is electrically connected with described processing module and described control module respectively, for the charging of described processing module and electric capacity provides power supply;
Described processing module is electrically connected with described control module, and described control module is electrically connected with described capacitance sensing unit;
Described processing module is used for sending drive signal to described control module, controls described capacitance sensing unit and discharges and recharges to drive described control module, and described processing module is tried to achieve capacitance by the duration of charging that measures described capacitance sensing unit.
Preferably, capacitance electronic type fuel sensor described in the utility model also comprises communication unit, and described communication unit is electrically connected with described electric capacity/liquid level converting unit, is used to realize the communication with external unit.
Compared with prior art, capacitance electronic type fuel sensor described in the utility model, simple and be easy to make, it is excessive to have solved distribution parameter common in the condenser type fuel sensor, capacitance parameter is difficult for the accurately problem of measurement, and capacitance measurement circuit and algorithm that capacitance electronic type fuel sensor described in the utility model adopts can effectively reduce the error of measured capacitance value.
Description of drawings
Fig. 1 is the structured flowchart of capacitance electronic type fuel sensor described in the utility model;
Fig. 2 is the structural drawing of a kind of concrete enforcement of capacitance electronic type fuel sensor described in the utility model;
Fig. 3 is the capacitator charging circuit figure of a kind of concrete enforcement of capacitance electronic type fuel sensor described in the utility model;
Fig. 4 is the circuit diagram of capacitance measurement unit of a kind of concrete enforcement of capacitance electronic type fuel sensor described in the utility model;
Fig. 5 is a kind of circuit diagram of concrete enforcement of the communication unit of capacitance electronic type fuel sensor described in the utility model.
Embodiment
As shown in Figure 1, the utility model provides a kind of capacitance electronic type fuel sensor, and it comprises capacitance sensing unit 11 and capacitance measurement unit 12, electric capacity/liquid level converting unit 13 and communication unit 14, wherein,
Described capacitance sensing unit 11 is assembled tube type capacity cells, comprises metal outer pipe and metal inner pipe, and described metal outer pipe and described metal inner pipe constitute the fuel liquid level sensor capacitor; Described capacitance sensing unit 11 is used for fuel liquid level is converted to relevant capacitance value;
The metal outer pipe of described capacitance sensing unit 11 and metal inner pipe are connected to the input end of described capacitance measurement unit 12 respectively by lead-in wire;
Described capacitance measurement unit 12 is used to measure the capacitance of described capacitance sensor unit 11;
Described electric capacity/liquid level converting unit 13 is electrically connected with described capacitance measurement unit 11, is used for the capacitance from described capacitance measurement unit 11 is converted to liquid level;
Described communication unit 14 is electrically connected with described electric capacity/liquid level converting unit, is used to realize the communication with external unit.
Preferably, described capacitance measurement unit 12 comprises processing module, control module and power module, wherein,
Described power module is electrically connected with described processing module and described control module respectively, for the charging of described processing module and electric capacity provides power supply;
Described processing module is electrically connected with described control module, and described control module is electrically connected with described capacitance sensing unit;
Described processing module is used for sending drive signal to described control module, controls described capacitance sensing unit and discharges and recharges to drive described control module, and described processing module is tried to achieve capacitance by the duration of charging that measures described capacitance sensing unit.
Preferably, described processing module sends drive signal with a predetermined period to described control module, controls described capacitance sensing unit with equifrequent and discharges and recharges to drive described control module.
As shown in Figure 2, capacitance sensing of the present utility model unit 11 adopts two concentric aluminium tubes respectively as two pole plates of capacitor, filled media when the fuel liquid level in the fuel tank is lower than the aluminum pipe bottom in the two-plate is an air, the equivalent capacitance value minimum of the capacitor that be made of two-plate this moment, after liquid level raises, liquid level cover part length increases, and the equivalent capacity of appropriate section increases.Can get by the electric capacity computing formula:
C＝C1+C2；
Wherein, C is a total capacitance, and C1 is filled media partition capacitance not, and C2 is the filled media partition capacitance;
C1＝ξ
1S
1/d，C2＝ξ
2S
2/d；
S
1=do not fill fuel oil part equivalent capacity pole plate area;
S
2=filling fuel oil part equivalent capacity pole plate area;
ξ
1=air dielectric specific inductive capacity; ξ
2=fuel oil medium specific inductive capacity;
From the above, C=ξ
1S/d+ (ξ
2-ξ
1) S
2/ d, wherein, S=S
1+ S
2
Along with the increase of fuel liquid level height, equivalent capacity is linear growth, thereby can realize the conversion of liquid level/capacitance signal.
When practical operation, also can use the pole plate of the pole plate of other shapes and material as capacitor, as stainless steel, metal materials such as copper need to use anode oxidation process to improve the class of insulation on the capacitor plate surface or spraying PTFE (teflon) improves product corrosion resistance and stability.
After inside and outside tubular pole plate is converted to capacitance with liquid level signal, the electric capacity two-plate is connected to the input end of signal transformation wiring board by lead-in wire, capacitor is discharged and recharged with equifrequent by charge-discharge circuit, the electric capacity both end voltage realizes that by the comparator circuit of back level the electric capacity both end voltage reaches preset voltage upset constantly, thereby the generation external interrupt signal is by Measurement of capacitor duration of charging measurement capacitance.
Capacitor charging circuit adopts constant-current source circuit, circuit theory as shown in Figure 3, when discharge circuit and capacitor disconnection, capacitor enters charged state, and circuit shown in Figure 3 is a Source type current source, its charging current size is by in-phase end preset voltage and feedback resistance decision, constant current source output current I=U1/R2, because the effect of constant current source, the capacitor charging process is a constant-current charge, duration of charging is directly proportional with capacitor voltage at both ends, satisfies:
Thereby can try to achieve capacitance by measuring capacitor charge time.
When practical operation, also can adopt as commonly used in the multimeter to apply ac-excited mode and measure the mode of capacitor plate two ends ac voltage and measure capacitance.But with present experience, the mode of measuring the duration of charging is more accurate under identical scale and cost condition.
Below in conjunction with Fig. 4, Fig. 5 the measuring principle of electric capacity is further explained:
1, power unit:
Power unit adopts integrated regulator to carry out voltage transformation, for MCU provides stable supply voltage.The sensor capacitance charge-discharge circuit adopts Source type current source that operational amplifier constitutes as constant current source as shown in Figure 4, produces drive triode V4 control measured capacitance device by MCU and discharges and recharges.
2, RS232 serial ports output circuit
RS232 serial ports output circuit adopts V6 and V7 to constitute the two poles of the earth amplifying circuit as shown in Figure 5, realizes level conversion and electric the isolation.
The capacitance of capacitor is converted to by calculation procedure after the remaining oil value, pass through communication program, asynchronous/synchronous serial communication the mouth built-in by MCU sends in instrument or the bus module through the signal end of level shifting circuit by fuel-quantity transducer, realizes the collection and the transmission of fuel oil signal.
The advantage that capacitance electronic type fuel sensor has is simple in structure, precision is high, the fuel oil measure of the change is accurate and cost is low, with a rectangular parallelepiped 300L volume, 600 millimeters high fuel tanks are example, when using swing arm fuel sensor or tongue tube fuel sensor, precision can only reach ± 10L～± 20L, and the precision of using capacitance electronic type fuel sensor can reach ± 0.5L in, be convenient to driver and supvr and grasp accurate more fuel consume information.Capacitance electronic type fuel sensor is simple in structure, and cost is low, and than the tongue tube fuel sensor with same precision, its cost is the latter's 30%～50% only, is a kind of fuel sensor with practical value.
Multinomial waterproof and the corrosion-resistance treatment of the utility model by capacitor is carried out, guaranteed that sensor has the ability of long-term continuous working, product has the range designation function simultaneously, product can be realized the demarcation of parameter by wiring board before installation, eliminated the precise decreasing that different integrated regulator output voltage errors and resistive element resistance error cause, different sensors has equal measuring accuracy in having guaranteed to produce in batches.
The utility model selects for use the polytetrafluoroethylmaterial material with low-k and temperature coefficient of permittivity as insulating material in the product installation and design, has eliminated the measuring error that capacitance variation that high distributed capacitance that common insulating material brings and distributed capacitance thereof cause with temperature, humidity and environmental factor such as aging is brought.
This product section parameter is as follows:
Measuring accuracy:＜0.5%F.S.;
Operating voltage: 20-30VDC;
Working temperature :-20 ℃～80 ℃.
More than explanation is just illustrative for the utility model; and it is nonrestrictive; those of ordinary skills understand; under the situation that does not break away from the spirit and scope that the utility model claim limited; can make many modifications; change, or equivalence, but all will fall in the protection domain of the present utility model.
Claims (3)
1. a capacitance electronic type fuel sensor is characterized in that, it comprises capacitance sensing unit and capacitance measurement unit and electric capacity/liquid level converting unit, wherein,
Described capacitance sensing unit is the assembled tube type capacity cell, comprises metal outer pipe and metal inner pipe, and described metal outer pipe and described metal inner pipe constitute the fuel liquid level sensor capacitor; Described capacitance sensing unit is used for fuel liquid level is converted to relevant capacitance value;
The metal outer pipe of described capacitance sensing unit and metal inner pipe are connected to the input end of described capacitance measurement unit respectively by lead-in wire;
Described capacitance measurement unit is used to measure the capacitance of described capacitance sensor unit;
Described electric capacity/liquid level converting unit is electrically connected with described capacitance measurement unit, is used for the capacitance from described capacitance measurement unit is converted to liquid level.
2. capacitance electronic type fuel sensor as claimed in claim 1 is characterized in that,
Described capacitance measurement unit comprises processing module, control module and power module, wherein,
Described power module is electrically connected with described processing module and described control module respectively, for the charging of described processing module and electric capacity provides power supply;
Described processing module is electrically connected with described control module, and described control module is electrically connected with described capacitance sensing unit;
Described processing module is used for sending drive signal to described control module, controls described capacitance sensing unit and discharges and recharges to drive described control module, and described processing module is tried to achieve capacitance by the duration of charging that measures described capacitance sensing unit.
3. capacitance electronic type fuel sensor as claimed in claim 2 is characterized in that it also comprises communication unit, and described communication unit is electrically connected with described electric capacity/liquid level converting unit, is used to realize the communication with external unit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2009201515207U CN201508209U (en) | 2009-04-28 | 2009-04-28 | Capacitance electronic fuel sensor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2009201515207U CN201508209U (en) | 2009-04-28 | 2009-04-28 | Capacitance electronic fuel sensor |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN201508209U true CN201508209U (en) | 2010-06-16 |
Family
ID=42469336
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN2009201515207U Expired - Lifetime CN201508209U (en) | 2009-04-28 | 2009-04-28 | Capacitance electronic fuel sensor |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN201508209U (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102589648A (en) * | 2012-03-15 | 2012-07-18 | 济南中森机械制造有限公司 | LNG (liquefied natural gas) liquid level gauge and method for measuring liquid level |
| CN108533613A (en) * | 2018-04-23 | 2018-09-14 | 佛山市梅雨科技有限公司 | A kind of intelligent electro-hydraulic servo bearing of automatic oiling |
-
2009
- 2009-04-28 CN CN2009201515207U patent/CN201508209U/en not_active Expired - Lifetime
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102589648A (en) * | 2012-03-15 | 2012-07-18 | 济南中森机械制造有限公司 | LNG (liquefied natural gas) liquid level gauge and method for measuring liquid level |
| CN108533613A (en) * | 2018-04-23 | 2018-09-14 | 佛山市梅雨科技有限公司 | A kind of intelligent electro-hydraulic servo bearing of automatic oiling |
| CN108533613B (en) * | 2018-04-23 | 2020-10-02 | 台州市黄岩巨科工贸有限公司 | An intelligent electro-hydraulic servo bearing with automatic oil filling |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| AV01 | Patent right actively abandoned |
Granted publication date: 20100616 Effective date of abandoning: 20090428 |