Staged Injection Staged Flow Ratio & Staged Flow 2 exp Calulator Spreadsheet

[MP]

With all the questions people have about calculating the "Staged Flow Ratio" and "Staged Flow 2 exp" options when setting up staged injection, I have made up a spreadsheet that will do the majority of the calculation for you.

You just need to input the following:

No. of Primary Injectors
Flow Rate of Primary Injectors (cc/min or lb/hr)
Stoichiometric AFR of fuel used in Primary Injectors.
No. of Secondary Injectors
Flow Rate of Secondary Injectors (cc/min or lb/hr)
Stoichiometric AFR of fuel used in Secondary Injectors.

The following gets spit out:

Staged Flow Ratio
Staged Flow 2 exp

Make sure that you enter the injector flow rates in the same units - cc/min, lb/hr, etc...

Please note that this does not take into account fuel pressure differences between a dual fuel system setup, if so equipped, so you will probably have to adjust the Staged Flow Ratio slightly to get the primaries and secondaries balanced correctly.

The example values in the speadsheet are for 6, 1000cc/min primaries on gasoline and 2, 1600 cc/min secondaries on methanol using a dual fuel system - seperate tanks, pumps, regulators, etc... In dyno testing, it was found that the Staged Flow Ratio had to be tweeked to 8.71 rather than the calculated 6.14 due to differences in fuel pressure between the two fuel systems.