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Fuel calculation model

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All fuel calculations in MaxxECU is based on % of the theoretic fuel amount required for an optimal engine.

The calculation is basically (VE table * MAP * Corrections) / Lambda table= Total fuel load % (simplified).


What we call the "Fuel load" can be well above 300% for some turbo engines.

The "fuel load" is the fuel amount required by the engine at any given time.


"Fuel load" is converted to a pulse needed to inject correct amount of fuel.

The "Fuel load" to "pulse width calculation" uses many factors like engine displacement, fuel type and injector flow.

The injector dead time is also added to the pulse width calculation.


All of these are pretty much constants so the "fuel load" to "pulse width" relationship is almost linear.


The value Injector duty is calculated from the amount of time the injector is open of the total available cycle time. 100% indicates that the injector is open the entire time and cant deliver any more fuel.

The fuel duty is very dependent on RPM as the cycle times get shorter at high rpm, the dead time also affects more at high RPM.

Injector duty is simply meant to indicate the usage % of the injectors. At 75-90% the injector looses linearly due to open / dead time.