RevC 07/15/13 Page 29
7) Right click on the upper frame of the LamdaTargetTable and select “Table
Conversion” from the list.
8) A window called “Channels” pops up; select AFR Target Table and hit OK.
Infinity: Air and Fuel
The Infinity ECU uses significantly different methods of calculating the fuel delivery
requirements and outputs than previous AEM products.
Measured data from sensors, i.e. Manifold Absolute Pressure (MAP [kPa]), Air
Temperature, Coolant Temperature, and Engine RPM are acquired. The ECU uses this
sensor data in combination with Volumetric Efficiency (VE%) to estimate airflow.
The Volumetric Efficiency is a percentage of air and fuel that actually enters the cylinder
during induction relative to the volumetric capacity (rated displacement) of the cylinder
under static conditions. The VE lookup table is a 2-axis lookup table, with load values
(typically MAP [kPa]) versus Engine RPM. In each table cell, the Engine RPM
corresponds with a specific MAP [kPa], and a Volumetric Efficiency is defined for that
cell.
The Volumetric Efficiency is combined with temperature sensor data to estimate a
compensated Mass Airflow. The ChargeTempBlend table dictates what ratio of air
temperature to coolant temperature is used at specific Engine RPM to adjust the density
of the inducted air. A higher number gives priority to Coolant Temperature, and is seen
at lower Engine RPM.
Once Mass Airflow has been calculated using the tables above, the Infinity ECU will
look up the Target Lambda (AFR) and then calculate the fuel requirements. Target AFR
will be used as a main parameter in determining fuel injector flow rate. The
LambdaTargetTable (below Left) and AFR Target Table conversion table (below Right)
will have default values. Based on the calculated Mass Airflow, the Infinity ECU will
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