Massflow are caulucation for fuel(Diesel)

[AutoEngineer]

Hello ,
I need to calculate the the mass flow rate of fuel (diesel) with respect to certain valve actuations.

As shown in picture, the fuel is injecting into the exhaust path , with the help of one electronically controlled valve and one mechanical valve. I know the pressure (P1) before the electronically controlled valve. and i know the mass flow rate of fuel after the electronically controlled valve. I want to calculate the pressure P2 after the electronically controlled valve and mass flow rate of the fuel after mechanical valve. Mechanical valve opens if the pressure P2 reaches certain threshold and closes with certain pressure.I have an mass flow balance equation to calculate the pressure P2 . (But to make this equation to work i should know the mass flow after mechanical valve ).

Can anyone help me how to calculate the mass flow after mechanical valve with an equation?

 

[billy_joule]

Hello ,
and i know the mass flow rate of fuel after the electronically controlled valve.

If you know that, then by conservation of mass you also know the answer to this question:

Can anyone help me how to calculate the mass flow after mechanical valve with an equation?

So it's unclear what you do and don't know, what measuring devices are actually in the system? Flow meters? pressure transducers/gauges etc?
How are the valves controlled? Do you have a valve position output? Why is there two valves at all? Do you know the flow factor of your valves?
https://en.wikipedia.org/wiki/Kv_(flow_factor)

EDIT:
Is this the same system you asked about in this thread?
https://www.physicsforums.com/threads/liquid-mass-flow-equation.824696/

gmax137's questions are on the right path, can you answer them?