Maths question: Calculating Fuel flow from engine data

[Frozennova]

I'm currently making a small Pi based Python script to pull engine data from an aftermarket ECU in car and cannot for the life of me anywhere find how I would calculate fuel flow

I have all of the sensor and hardware data (Engine speed, Injector pulse width in milliseconds, injector flow rate, injector dead time) I think I need but im having trouble working out how to get the end result I'm looking for

 

[Frozennova]

Fuel flow between what two points?

Maybe I should have worded it a little differently.

I want to calculate the volume of fuel injected

 

[Frozennova]

Think I have it, or at least something that spits out some sane values anyway

lph = (RPM * ((injectorFlow / 60000 ) * (PW - DeadTime)) * 4) * 60 / 1000

Plugging some values taken from a data log at part throttle and 31mpg

lph = (1845 * ((650 / 60000 ) * (2.2 - 1)) * 4) * 60 / 1000 = 5.75

Not really that simple because rail pressure is directly linked to manifold pressure which is going to make your flow rate all over the place in practice. You would need to factor that in.

If it works out to be a problem I have the MAP sensor value available to offset the injector flow rate

Edit: forgot to account for the fact that all injectors are fired per engine cycle which is 2 revolutions

So the correct formula should be

lph = (RPM/2 * ((injectorFlow / 60000 ) * (PW - DeadTime)) * 4) * 60 / 1000