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VVC AUTO 85.5 - Smog Technician - Level 1 - Lambda

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VVC AUTO 85.5 - Smog Technician - Level 1 - Lambda

  1. 1. Determining how close the A/F ratio is to the stoichometric point using exhaust gas analysis. Presented to East Bay ATA, Hayward, CA May 5, 2004 By: Robert J. Schrader President, Bridge Analyzers, Inc.
  2. 2. point.ricstoichometperfectthe-balanceinare O2forDemandeCombustiblandO2when1.000toequalisLamdba oxidation.completeattaintoO2forDemandeCombustibl thevsProcessCombustionthetoavailableO2ofratiotheisLambda )( OxygenfordemandesCombustibl availableOxygen Lambda • Lambda is Oxygen Balance
  3. 3.  Lambda control is necessary for peak combustion efficiency in the Engine.  Lambda control is necessary for peak CAT efficiency.  Lambda Control Improves Reliability, Fuel Economy and Lowers Emissions.
  4. 4.  Engine out CE for Gasoline Fuel is no better than 95%.  Tailpipe-out CE for CAT equipped vehicles improves to 99.0-99.5%.  Factor of 10 improvement  Required for Current Emission Standards  CAT CE is very Lambda-Dependent
  5. 5. 0.00 0.50 1.00 1.50 2.00 2.50 3.00 3.50 4.00 0.90 0.91 0.92 0.93 0.94 0.95 0.96 0.97 0.98 0.99 1.00 1.01 1.02 1.03 1.04 1.05 1.06 1.07 1.08 1.09 1.10 Lambda %Concentration CO - Carbon Monoxide H2 - Hydrogen O2 - Oxygen 11.00 11.50 12.00 12.50 13.00 13.50 14.00 14.50 15.00 15.50 16.00 0.90 0.91 0.92 0.93 0.94 0.95 0.96 0.97 0.98 0.99 1.00 1.01 1.02 1.03 1.04 1.05 1.06 1.07 1.08 1.09 1.10 Lambda %Concentration CO2 - Carbon Dioxide
  6. 6. 0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% 0.950 0.960 0.970 0.980 0.990 1.000 1.010 1.020 1.030 1.040 1.050 Oxidation Efficiency Reduction Efficiency
  7. 7. 0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35 0.40 0.45 0.50 0.950 0.960 0.970 0.980 0.990 1.000 1.010 1.020 1.030 1.040 1.050 0 100 200 300 400 500 600 700 800 900 1000 H2 - Hydrogen NOx - Oxides of Nitrogen CO - Carbon Monoxide
  8. 8.  NOx Reduction Bed  Requires Lambda to be not greater than 1.020.  CO/HC Oxidation Bed  Requires Lambda to be not less than 0.980.  Modulation Depth  Cycles Rich and Lean Between the Limits Above.
  9. 9. point.ricstoichometperfectthe- balanceinaredemandeCombustiblandO2when1.000toequalisLambda oxidation.completeattaintoO2fordemandecombustibl thetoO2)(asavailableOxygenofratiotheascalculatedisLambda )( OxygenfordemandeCombustibl availableOxygen Lambda
  10. 10.  Lambda = 1.000 when the Oxygen available and Combustible Oxygen demands are in balance.  This is the point of perfect stoichometric balance.  At this point the A/F ratio is 14.71 to 1.00 for Gasoline.  Thus, A/F = 14.71 x Lambda
  11. 11.  Brettschneider Lambda uses all the oxygen- bearing and combustible-bearing gases.  Balance Equation - Calculation not affected by the degree of oxidation.  Method is insensitive to combustion efficiency.  Either Pre-CAT or Post-CAT gases may be used.
  12. 12.  = 1.000 when Oxygen available and Combustible demands are in balance.  ECM controls =1.000 at 0.5-1.0 Cycles/Sec using ‘lambda sensor’ input.  3-Way CAT operation requires 0.980 to 1.020  Lambda can be confirmed by exhaust gas measurement, either pre or post CAT.
  13. 13.  calculated from exhaust gas indicates air-fuel mixture independent of the engine controls.  calculated from exhaust gas indicates air-fuel mixture independent of combustion efficiency.  Cold (Open Loop) vs Hot (Closed Loop) vs CAT light-off operation can be evaluated.  can be used to tune systems which do not have closed-loop control.
  14. 14.  High Combustion Efficiency: Measure O2 post CAT - every 5% air leak adds 1.0% O2 to gases.  Low Combustion Efficiency: Add CO and CO2 - should equal 15% for Gasoline.  Compare both Methods. If O2 indicates air dilution - then confirm this with low CO and CO2 sum. They should agree.
  15. 15.  Created by iATN Tech Support staff, and available to iATN members on-line at http://members.iatn.net/tech/lambda.ht ml  Plug and Play either 4 or 5 gas values.  Can select either US or European gasoline constants.  Operates in Java - can be saved and run off-line by any Java-equipped net browser.
  16. 16.  Available as email attached Excel file by contacting: support@bridgeanalyzers.com  Plug and Play either 4 or 5 gas values.  Can select either US or European gasoline constants.  Operates on any PC with Excel - can be saved and run off-line using Microsoft Excel.
  17. 17.  Written by Miles Wada using the Brettschneider equation - a’la Bridge.  Available for download at: http://www.aeswave.com/
  18. 18.  Written by Greg Meyer using the Brettschneider equation - a’la Bridge.  Available from Greg via email at: gsmeyer@attbi.com  Operates on Microsoft PC in Excel.
  19. 19. A/F = 14.71 x Lambda
  20. 20.  September  1993 Mazda Protege  1.8L, Manual Trans, No EGR  Failed Smog Check for Timing (FA99), GP HC & NOx
  21. 21. ASM 5015 Result HC CO CO2 NO O2 RPM GP 247 0.49 13.8 2000 1.2 1624 Standards HC CO CO2 NO O2 Fail 92 0.55 716 GP 281 2.05 1,961 AVG 21 0.06 150
  22. 22.  November  1993 Mazda Protege  1.8L, Manual Trans, No EGR  Failed its Pre-repair Baseline Inspection at a CAP station for for Timing (FB48), HC & NOx
  23. 23. ASM 5015 Result HC CO CO2 NO O2 RPM Fail 186 0.43 16 1095 1 1683 Standards HC CO CO2 NO O2 Fail 92 0.55 716 GP 281 2.05 1,961 AVG 21 0.06 150
  24. 24.  December  1993 Mazda Protege  1.8L, Manual Trans, No EGR  Passed & Certified
  25. 25. ASM 5015 Result HC CO CO2 NO O2 RPM Pass 74 0.21 15.5 308 0.08 1590 Standards HC CO CO2 NO O2 Fail 92 0.55 716 GP 281 2.05 1,961 AVG 21 0.06 150

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