Microsoft PowerPoint - CCS potentiometeric2

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1 Oxygen Sensor 1957 : K.Kiukkola and C.Wagner oxygen sensor using zirconia- or thoria-base solid solution with CaO, MgO, or Y O 3 Applications 1. Automotive industry - lambda control for maximizing the efficiency of 3-way catalyst. Metallurgical Industry - steel manufacturing and copper refining (for optimal combinations of selective reduction and oxidation of impurities at high temperature.) 3. industry 4. Biotechnological industry

2 Atomic Structure: Stabilized Zirconia Y M. Chiang, Physical s

3 Ionic conduction in Stabilized Zirconia J.A.Kilner and B.C.H.Steele, Chapter 5 in Nonstoichiometric Oxide edited by O.T. Sørenesen (1981)

4 Ionic conduction in Stabilized Zirconia Y O Y V O ZrO ' Zr O O Sc O Sc V O ZrO ' Zr O O Yb O Yb V O ZrO ' Zr O O MgO Mg + V + O ZrO '' Zr O O CaO Ca + V + O ZrO '' Zr O O J.A.Kilner and B.C.H.Steele, Solid State Ionics, 8, 01 (1983)

5 The effect of stabilized concentration on the conductivity Y O Y V O ZrO ' Zr O O The maximum ionic conductivity is observed when the concentration of acceptor-type dopant is close to the minimum necessary to completely stabilized the cubic fluorite-type phase. Further addition of acceptor ' ' [ VO ] [ YZr VO YZr] Localization of oxygen vacancy σ J.A.Kilner and B.C.H.Steele, Chapter 5 in Nonstoichiometric Oxide edited by O.T. Sørenesen (1981)

6 Oxygen sensor for steel making In 1966 Continuous analysis of waste gas to find optimal amount of secondary air. (Matsushita system) Needle sensor for on-line use - invented by Janke and Schwerdfeger in commercialized by Yamarie Electronics Co. In plasma spray of Cr/Cr O 3 and MSZ layer K.S.Goto and M.Susa, Sensor Technology Vol.1, pp (1988)

7 Potentiometeric Oxygen Sensor (Lambda Sensor) λ= (A/F) (A/F) st.303rt Po (air) V max = log 4F Po eq (exh.) Engine Catalytic Converter

8 Example 1 1 CO( g) + O( g) = CO( g) o Δ G = RTln K = 8, T( J) CO CO exp 8, KCO = = 1/ T CO O = 0.03, =, T = 900K CO CO CO 8, KCO = = exp / = * CO O 3 O = 11 = ( input) =, ( input) = 0.04, T = 900K CO ( eq.) = 0.0, ( eq.) = 0.08 CO O CO 11

9 Example : Rich to Stoichiometric ( eq. ) = ( input) ( input) CO CO O co(input) o(input) co(eq.) co(eq.) o(eq.) E E E E E E E E E E E E E E E-09 Near the stoichoimetric point

10 Example 3: Lean to Stoichiometric 1 O ( eq.) = ( ) ( ) O input CO input CO ( eq.) = 1/ O CO co(input) o(input) co(eq.) o(eq.) co(eq.) E E E E E E E E E E E E E-11 Near the stoichoimetric point

11 emf at rich, stoichiometeric, and lean points Rich conditions Stoichiometric Points Lean conditions 1 CO( input) > O ( input) 1 CO( input) O ( input) 1 CO( input) < O ( input) O O O ( eq.) 10 ( eq.) 10 ( eq.) emf emf emf 800mV 450mV 100mV co(input), co (input), o (input) co(eq.), co (eq.), o (eq.) Yttria-Stabilized Zirconia(O - ionic conductor)

12 Incomplete combustion reaction 1 CO( g) + O( g) = CO( g) CO =, = 0.04 O After combustion (incomplete reaction) = 0.04, = 0.00, = CO O CO = 0.030, = 0.005, = CO O CO = 0.040, = 0.010, = CO O CO = 0.060, = 0.00, = CO O CO Non-equilibrium characteristics Depends on engine condition, firing condition, spark plug,. Pt CO ( eq.) = 0.0 ( eq.) = O CO ( eq.) = Equilibrium characteristics Uniquely determined by air/fuel(input)

13 Equilibrium and non-equilibrium exhaust

14 Lambda Sensor: Sensing Characteristics We should detect the equilibrium O concentration using Pt electrode thermodynamic equilibrium free oxygen E.M.Logothesis, Sensor Technology, Vol.3, pp (1991)

Calculation of Nernst emf at 500-800 o C F=96,487 C/mol R=8.3144J/deg.mol E=.15410-5 Tln(Po I /Po II ) [V] =4.

15 Calculation of Nernst emf at o C F=96,487 C/mol R=8.3144J/deg.mol E= Tln(Po I /Po II ) [V] = Tlog(Po I /Po II ) [V] = Tlog(Po I /Po II ) [mv].303rt Po (air) V max = log 4F Po eq (exh.) Joule/Coulomb=Volt

16 Lambda Sensor: Lean Shift 1

17 Lambda Sensor: Lean Shift Assume stoichiometeric exhaust gas * DH J H = [ C H (0) C ( )] H l l * DO JO = [ C (0) ( )] O C O l l stoichiometeric at the surface of protective layer J C H H = J O (0) = C (0) O H O N( CH (0): CO (0) = :1) * * DH D O [ CH (0) C ( )] [ (0) ( )] H l C O C O l l = l * * DH D O [ CO (0) C ( )] [ (0) ( )] H l C O C O l l = l * D C () l C () l H 1 H 1 O * = DO C (0) (0) O C O CH () l C () O l > 1 1 < 1 C (0) C (0) O O C () l > C () l H O Fuel-rich at the electrode surface Porous enough to prevent lean shift Dense enough to prevent catalyst poisoning

18 Lambda Sensor: Lean Shift 3 K.Saji et al., J.Electrochem.Soc., 135(7), 1686 (1988)

19 Lambda Sensor: structure Nippon Denso Delphi Why only 4 makers? 1. Large scale of investment. High level of reliability (quality, reproducibility) 3. Should persuade conservative Automakers

20 Let s discuss design factor!

21 Example

22 Example

23 Terminology The other names of potentiometric oxygen sensor for gasoline engine 1) Zirconia EGO(Exhaust Gas Oxygen) sensor ) Zirconia HEGO(Heated Exhaust Gas Oxygen) sensor 3) Lambda Sensor 4) Oxygen sensor The wire number of the sensors 1 wire : (+), earth on the car body wires : 1 line for (+), 1 line for (-) 3 wires : lines for heater, 1 lines (+) signal, earth on the car body 4 wires : lines for heater, 1 line for (+), 1 line for (-)

24 Pollutant emission concentrated at the early stage of driving Engine Output Catalytic Converter Tail Pipe Concentration of emission at the cold start FTP LA4

25 Evolution of Lambda Sensor Thimble Type Heated Thimble Type Planar Type with ref. Schematic Structure Air reference Total part # Response Warm-up State of art Yes ~0 Slow Long (3min.) Mass Production Yes ~3 Moderate Short (30-40 sec.) Mass Production Yes ~3 Fast Very short (10-1 sec.) 1%

emission Air reference Water proof Heated Thimble Type

26 Planar Type Lambda Sensor with air reference Small Thermal Mass Quick Warm-up of sensor Less pollutant emission Air reference Water proof Heated Thimble Type Planar Type with ref. H.Neumann et al., SAE paper No (1997)

27 Planar Type Lambda Sensor with air reference Fast light-off sensor Pollutant emission concentrated at the cold start period. (about 50% of pollutant emission during 30-minutes driving is emitted at the first 1- minutes of cold start.) requires the fast activation of 3-way catalyst and oxygen sensor H.Neumann et al., SAE paper No (1997)

28 Evolution of Lambda Sensor Schematic Structure Thimble Type Heated Thimble Type Planar Type with ref. Planar Type without ref. Air reference Total part # Response Warm-up State of art Yes ~0 Slow Long (3min.) Mass Production Yes ~3 Moderate Short (30-40 sec.) Mass Production Yes ~3 Fast Very short (10-1 sec.) 1% No 14 Fast Very short (10-1 sec.) Proto-type Since 1999 (SAIT, BOSCH)

29 Planar Lambda Sensor without air reference O +4e - O - Protective layer YSZ electrolyte e.m.f. O - Load resistance DC 14V O O +4e - Heater voltage(dc 14V) - Just after cold start: cell resistance > load resistance: e.m.f.=14v - After warm-up: cell resistance << load resistance: e.m.f.=0~1v RT Po (ref.) V= I p R cell + ln 4F Po (exh.) -I p as small as possible V becomes almost same to Nernst e.m.f. - Simple housing (No need to make air reference) Quick warm-up, Simple housing, Convenient fabrication

30 Example 삼성종기원, 자동차용산소센서개발 삼성종합기술원 ( 원장임관 ) 은삼성전기 ( 대표이형도 ) 와공동으로탄화수소 일산화탄소 질소산화물등유해배기가스의배출을줄이는데사용되는가솔린자동차용산소센서를개발했다고 5 일밝혔다. 삼성종기원이 년간 8 억원을들여개발한이제품은센서의작동시간이 30 초에서 3 분이소요되는기존의튜브형산소센서와달리센서의작동개시시간이 1 초에불과한공기기준극이없는소형평판형산소센서로엔진시동초기의유해배기가스를현저히줄일수있다. 이제품은또공기기준극을없애센서제조및하우징이용이할뿐만아니라센서하우징부품수를 30% 줄여가격경쟁력을크게높인점이특징이다. [ 전자신문 1998 년 11 월 6 일자 ]

31 Lambda sensor: poisoning by lead or lubricant phosphorous content P.S.Brett et al., SAE paper No

32 Air/Fuel Sensor for Catalyst Monitoring 운전자가자신의승용차에장착되어있는배기가스정화용 3원촉매의열화및고장을신속히검지, 유해자동차배기가스를저감. Air HC, 3-way H O Air flow Engine CO, Catalytic CO Exhaust Sensor NOx Converter N Fuel ECU 신호비교 촉매고장 OBD(On Board Diagnosis) 규정 OBD I, 1994 in USA: 촉매의고장판단 OBD II, 1998 in USA: 촉매열화의정량화 EURO III, 000 in USA: 촉매의고장판단

33 OBD (On-Board Diagnostics) I and II Aims 1. Reduce high in-use emission caused by emission-related malfunction. Reduce time between occurrence of a malfunction and its detection and repair 3. Assist in the diagnostics and repair of emission-related problems Methodology - MIL ( Malfunction Indicator Light) Criterion - Malfunction must be detected before emissions exceeds standards by a specified threshold (generally 1.5 emission standard) - In most cases, malfunction must be detected within driving cycles History - OBD I adopted in 1985 for OBD II adopted in 1989 for 1994

34 OBD (On-Board Diagnostics) I and II OBD I OBD II Oxygen Sensor Oxygen Sensor (Enhanced) EGR System EGR System (Enhanced) Fuel System Fuel System (Enhanced) Electronic Input Component Electronic Input Components Diagnostic Information Electronic Output Components - Fault Codes Catalyst Efficiency Catalyst Heating Engine Misfire Evaporative System (leak check/function) Secondary Air System Diagnostic Information - Fault Codes - Engine parameter Data - Freeze Frame Engine Parameters - Standardization

35 OBD (On-Board Diagnostics) I and II Monitoring Items 1. Output voltage. response rate 3. shift in switch point 4. internal heater performance 5. and other parameter which can affect emissions Malfunction criterion Malfunctions are to be detected before emissions exceed 1.5 times the standard Other OBD II items that can be detected by the oxygen or A/F sensor 1. Misfire Detection (to prevent excessive emission and catalyst damage). Catalyst monitoring

Microsoft PowerPoint - ch03ysk2012.ppt [호환 모드]

Microsoft PowerPoint - ch03ysk2012.ppt [호환 모드] 전자회로 Ch3 iode Models and Circuits 김영석 충북대학교전자정보대학 2012.3.1 Email: kimys@cbu.ac.kr k Ch3-1 Ch3 iode Models and Circuits 3.1 Ideal iode 3.2 PN Junction as a iode 3.4 Large Signal and Small-Signal Operation