AEM 30-71XX Infinity Stand-Alone Programmable Engine Mangement System Full Manual - Manual (Page 130)

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© 2014 AEM Performance Electronics
Infinity User Manual
VE & Airflow Based Tuning
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.