CN202814903U - Oxygen pump limited current measurement circuit of nitrogen oxygen sensor - Google Patents
Oxygen pump limited current measurement circuit of nitrogen oxygen sensor Download PDFInfo
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- CN202814903U CN202814903U CN201220455398.4U CN201220455398U CN202814903U CN 202814903 U CN202814903 U CN 202814903U CN 201220455398 U CN201220455398 U CN 201220455398U CN 202814903 U CN202814903 U CN 202814903U
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Abstract
The utility model discloses an oxygen pump limited current measurement circuit of a nitrogen oxygen sensor. The circuit comprises a controller, wherein the two ends of a main pump, an auxiliary pump, and of a measurement pump are respectively connected with a measurement branch circuit in parallel; each measurement branch circuit comprises a precision resistor and a diode, which are connected in series; and voltage sampling signal ends at two ends of the precision resistor are connected with an input end of the controller. The circuit is for use in the nitrogen oxygen sensor and used to measure the limited current of the oxygen pump; and, no matter how high the working voltage of the oxygen pump is, the limited current flowing through the oxygen pump can be precisely measured, so that the controller can accurately provide working voltage to the oxygen pump to further ensure the measurement precision of the nitrogen oxygen sensor.
Description
Technical field
The utility model relates to current measurement circuit, particularly the metering circuit of oxygen pump limit electric current in a kind of nitrogen oxide sensor.
Background technology
Energy-saving and emission-reduction have become the common issue with that society faces, and various countries are also more and more higher to the requirement of air quality, and automotive emission has become main atmosphere pollution.At present, usually select nitrogen oxide sensor to measure the concentration that contains NOx in the tail gas that discharges in the motor car engine after-treatment system, and the NOx concentration value of measuring according to nitrogen oxide sensor takes appropriate measures, reduce the NOx gas purging, thereby make the tail gas of discharging meet the requirement of national standard.
The nitrogen oxide sensor chip as shown in Figure 2, formed by several layers of zirconia ceramics compacting, in second layer zirconia pressure layer, be provided with two cavitys---the first cavity and the second cavity, be provided with main pump in the first cavity, be provided with service pump in the second cavity and measure pump, main pump, service pump and measurement pump are used for removing the O of tail gas
2, HC, CO, CO
2Deng to the influential gas of final NOx test result.The nitrogen oxide sensor ceramic chip adopts two many battery structures of cavity, by the measurement gas in the cavity is carried out locellus, step control, realizes the measurement to NOx, and principle is as follows:
Gas enters the first plenum chamber 5 by the first diffusion barrier 7, and the main pump that is comprised of main pump anodal 1 and main pump negative pole 2 in this chamber can pump into or pump the O in the first plenum chamber 5
2, and will not have composition (HC, CO and the H of complete oxidation in the exhaust
2) carry out oxidation.Like this, exhaust in the first plenum chamber 5 remaining not have the NOx of decomposition and an O of concentration very low (several ppm)
2Residual gas enters the second plenum chamber 6 through the second diffusion barrier 8, at this moment, the service pump that is comprised of main pump anodal 1 and service pump negative pole 3 further pumps remaining oxonium ion, so that only be left not have the NOx of decomposition in the gas, at this moment, the measurement pump that is comprised of main pump anodal 1 and measurement pump negative pole 4 can be reduced into N with NOx
2And O
2The O that NOx is decomposed out on potential electrode
2Measured pump is constantly taken away, produces the pump electric current, and the O that is pumped
2With the NOx that is decomposed certain relation is arranged, this moment is because taking O away
2And the pump electric current that produces has namely represented the NOx content in the gas, has namely finished the measurement of NOx nitrogen oxide sensor to NOx gas.
In the course of work of main pump, service pump, measurement pump, VP0, the VP1, the VP2 voltage that each oxygen pump are applied by controller, with the ability of control main pump, service pump, measurement pump pump oxygen, controller by the current value of reading current Table I P0, IP1, IP2 determine each loop the limiting current value.But applying in the process of voltage; because the requirement of control strategy; the voltage that often can occur applying is greater than the oxygen pump required voltage of electric current that reaches capacity; when voltage is far longer than the required limiting current voltage of oxygen pump; limiting current can be undergone mutation; the electric current that read by IP0, IP1, IP2 this moment also is not equal to limiting current, therefore can produce larger error, affects the measuring accuracy of nitrogen oxide sensor.
Summary of the invention
The technical matters that the utility model solves provides a kind of metering circuit of nitrogen oxide sensor oxygen pump limit electric current, and limiting current value that can Measurement accuracy oxygen pump further guarantees the measuring accuracy of nitrogen oxide sensor.
For solving the problems of the technologies described above, technical solution adopted in the utility model is as follows.
Nitrogen oxide sensor oxygen pump limit current measurement circuit, comprise controller, branch road in parallel one is measured respectively in the main pump of described nitrogen oxide sensor, service pump and measurement pump two ends, described measurement branch road comprises precision resistance and the diode that is connected in series, and the voltage sampling signal end at described precision resistance two ends connects the input end of controller.
Owing to adopted above technical scheme, the obtained technical progress of the utility model is as follows.
The utility model is applied in the nitrogen oxide sensor, be used for measuring the limiting current of oxygen pump, no matter how high the operating voltage of oxygen pump is, all can accurately measure the limiting current that flows through the oxygen pump, thereby make the controller can be exactly for the oxygen pump provides operating voltage, with the measuring accuracy of further assurance nitrogen oxide sensor.
Description of drawings
Fig. 1 is circuit diagram of the present utility model.
Fig. 2 is the structural representation of the utility model in the nitrogen oxide sensor chip.
Embodiment
Below in conjunction with concrete accompanying drawing the utility model is further elaborated.
Nitrogen oxide sensor oxygen pump holding circuit, its circuit diagram comprise controller M and three measurement branch roads shown in 1, measure branch road and comprise precision resistance and the diode that is connected in series, and the voltage sampling signal end at described precision resistance two ends connects the input end of controller M.
Wherein measure the branch road I and comprise precision resistance R1 and the diode D1 that is connected in series, the end of precision resistance R1 connects the A1 output terminal of controller, and the other end of precision resistance R1 connects the positive pole of diode D1, and the negative pole of diode D1 connects the A2 output terminal of controller.The voltage sampling signal end at precision resistance R1 two ends connects input end AD1 and the AD2 of controller M, and controller M is used for the signal according to AD1 and the collection of AD2 end, calculates the terminal voltage of precision resistance R1.
Measure the branch road II and comprise precision resistance R2 and the diode D2 that is connected in series, the end of precision resistance R2 connects the A1 output terminal of controller, and the other end of precision resistance R2 connects the positive pole of diode D2, and the negative pole of diode D2 connects the A3 output terminal of controller.The voltage sampling signal end at precision resistance R2 two ends connects input end AD3 and the AD4 of controller M, and controller M is used for the signal according to AD3 and the collection of AD4 end, calculates the terminal voltage of precision resistance R2.
Measure the branch road III and comprise precision resistance R3 and the diode D3 that is connected in series, the end of precision resistance R3 connects the A1 output terminal of controller, and the other end of precision resistance R3 connects the positive pole of diode D3, and the negative pole of diode D3 connects the A4 output terminal of controller.The voltage sampling signal end at precision resistance R3 two ends connects input end AD5 and the AD6 of controller M, and controller M is used for the signal according to AD5 and the collection of AD6 end, calculates the terminal voltage of precision resistance R3.
The limiting current metering circuit be applied in the nitrogen oxide sensor chip structural representation as shown in Figure 2.A1 termination main pump positive pole 1, A2 termination main pump negative pole 2, A3 termination service pump negative pole 3, the A4 termination is measured pump negative pole 4.Main pump positive pole 1, main pump negative pole 2 form main pump oxygen pump, and main pump positive pole 1, service pump negative pole 3 form service pump oxygen pump, main pump positive pole 1, measure pump negative pole 4 composition measurement pump oxygen pumps.
Controller M holds to each oxygen pump and applies voltage by A1A2 end, A1A3 end, A1A4 respectively, and the voltage that applies can guarantee the normal pump oxygen work of each oxygen pump in very little scope.Wherein the voltage of A1 end is fixed and voltage is higher than A2 end, A3 end, A4 terminal voltage, and controller M is by the size of feedback signal control A2 end, A3 end, A4 end output control voltage.
During test, the voltage that applies voltage VP0, VP1, VP2 when each oxygen pump is during less than the dead band voltage of diode, and the bypass electric current I 2, I5, the I8 that measure branch road equal 0, IP0=I1=I3, IP1=I4=I6, the IP2=I7=I9 that measure this moment.That is to say that the current value that reometer IP0, IP1, IP2 measure is the limiting current of oxygen pump.
The voltage of the voltage VP0 that main pump is applied as controller M is during greater than the dead band voltage of diode D1, diode D1 conducting, at this moment, controller M is by the voltage signal AD1 that gathers precision resistance R1 two ends, the value of AD2, calculate the terminal voltage of precision resistance R1, then go out to flow through the electric current of precision resistance R1 according to the computing the resistor value of precision resistance R1, namely obtain the size of the bypass electric current I 2 of diode D1.Pass through at last the limiting current value I3 that formula: I3=IP0-I2 calculates main pump.
In like manner, the voltage VP1 that service pump is applied as controller M is diode D2 conducting during greater than the dead band voltage of diode D2, at this moment, controller M is by the voltage signal AD3 that gathers precision resistance R2 two ends, the value of AD4, calculate the terminal voltage of precision resistance R2, then go out to flow through the electric current of precision resistance R2 according to the computing the resistor value of precision resistance R2, namely obtain the size of the bypass electric current I 5 of diode D2.Pass through at last the limiting current value I6 that formula: I6=IP1-I5 calculates service pump.
When controller M diode D3 conducting during greater than the dead band voltage of diode D3 to the voltage VP2 that measures pump and apply, at this moment, controller M is by the voltage signal AD5 that gathers precision resistance R3 two ends, the value of AD6, calculate the terminal voltage of precision resistance R3, then go out to flow through the electric current of precision resistance R3 according to the computing the resistor value of precision resistance R3, namely obtain the size of the bypass electric current I 8 of diode D3.Pass through at last formula: I9=IP2-I8 and calculate the limiting current value I9 that measures pump.
Claims (1)
1. nitrogen oxide sensor oxygen pump limit current measurement circuit, comprise controller, it is characterized in that: branch road in parallel one is measured respectively in the main pump of described nitrogen oxide sensor, service pump and measurement pump two ends, described measurement branch road comprises precision resistance and the diode that is connected in series, and the voltage sampling signal end at described precision resistance two ends connects the input end of controller.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201220455398.4U CN202814903U (en) | 2012-09-08 | 2012-09-08 | Oxygen pump limited current measurement circuit of nitrogen oxygen sensor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201220455398.4U CN202814903U (en) | 2012-09-08 | 2012-09-08 | Oxygen pump limited current measurement circuit of nitrogen oxygen sensor |
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| Publication Number | Publication Date |
|---|---|
| CN202814903U true CN202814903U (en) | 2013-03-20 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201220455398.4U Expired - Lifetime CN202814903U (en) | 2012-09-08 | 2012-09-08 | Oxygen pump limited current measurement circuit of nitrogen oxygen sensor |
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| Country | Link |
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| CN (1) | CN202814903U (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102841113A (en) * | 2012-09-08 | 2012-12-26 | 无锡隆盛科技股份有限公司 | Measuring circuit for oxygen pump limiting current in nitrogen-oxygen sensor |
| CN107764885A (en) * | 2017-12-04 | 2018-03-06 | 深圳市森世泰科技有限公司 | The apparatus and method for measuring gas concentration |
| CN108872349A (en) * | 2018-06-21 | 2018-11-23 | 西安创联电气科技（集团）有限责任公司 | The test method and device of nitrogen oxide sensor ceramic chip gas sensing property |
-
2012
- 2012-09-08 CN CN201220455398.4U patent/CN202814903U/en not_active Expired - Lifetime
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102841113A (en) * | 2012-09-08 | 2012-12-26 | 无锡隆盛科技股份有限公司 | Measuring circuit for oxygen pump limiting current in nitrogen-oxygen sensor |
| CN107764885A (en) * | 2017-12-04 | 2018-03-06 | 深圳市森世泰科技有限公司 | The apparatus and method for measuring gas concentration |
| WO2019109782A1 (en) * | 2017-12-04 | 2019-06-13 | 深圳市森世泰科技有限公司 | Device and method for measuring gas concentration |
| CN108872349A (en) * | 2018-06-21 | 2018-11-23 | 西安创联电气科技（集团）有限责任公司 | The test method and device of nitrogen oxide sensor ceramic chip gas sensing property |
| CN108872349B (en) * | 2018-06-21 | 2020-08-11 | 西安创研电子科技有限公司 | Method and device for testing gas sensitivity of nitrogen-oxygen sensor ceramic chip |
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| Date | Code | Title | Description |
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| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CX01 | Expiry of patent term | ||
| CX01 | Expiry of patent term |
Granted publication date: 20130320 |