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Delta O2 Table and Delta Lambda Table
The %O2 calculated by LambdaCAN and NOxCAN(g) modules is denoted as “O2R” and is
a wet (i.e. water taken into consideration in %O2 calculation), at chemical-equilibrium (i.e.
not frozen-equilibrium) %O2 measurement (see Appendix C). The Lambda (AFR, FAR,
PHI) calculated by the LambdaCAN and NOxCAN(g) modules is denoted as “LAMR” and
matches that calculated by mass flowrates of air and fuel entering the engine.
Sometimes users would like dry %O2 readings, or frozen-equilibrium %O2 readings, or dry
frozen-equilibrium readings, or readings that match another instrument. For this purpose, the
Delta O2 Table is used. The Delta O2 Table (found in the task “Open Delta Tables”) allows
the user to add a number (a “delta”) to the “O2R” calculated by the LambdaCAN and
NOxCAN(g) modules giving the “O2” parameter:
O2 = O2R + Delta O2 Table value
(interpolated from table)*
* except when O2R > 18 for which O2 = O2R, regardless of table data.
A Delta O2 Table can be created, edited, and saved as a text file (.txt) on your PC. The file
must be downloaded into the LambdaCAN or NOxCAN(g) module for it to be used. Unlike
the sensor calibration information (i.e. zero, span) which is stored in a memory chip in the
sensor’s connector, the Delta O2 Table is stored in the module.