Presentation on theme: "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."— Presentation transcript:
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.
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.
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
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
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.
= 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.
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.
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.
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.
Available as email attached Excel file by contacting: firstname.lastname@example.org 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.
Written by Miles Wada using the Brettschneider equation - ala Bridge. Available for download at: http://www.aeswave.com/
Written by Greg Meyer using the Brettschneider equation - ala Bridge. Available from Greg via email at: email@example.com Operates on Microsoft PC in Excel.