Turbo Car Auto Reserve Function

[Merlin]

Hi All

I have an Endurance race car that is Turbo Charged Rotary Engine
Setup is M130 2x PDM15 C127 Keypad LTC
Fuel System has a Reserve pot of 5 lts and its own pump
Main Pump is separate

Q is how would you create the reserve Auto function with the rising rate fuel pressure ?

Am i over thinking this by using a 3D table in the C127 and a User condition ?

I do have other non turbo cars with Auto reserve function that is fuel Pressure based , IE Enable reserve pump if FP below XXX Kpa
But on a turbo car this could be very dangerous, especially for a Rotary

All options considered, so Please share your thoughts

John P

[Stephen Dean]

Are you wanting this to act as a fail safe if the Primary pump fails, or to add extra fuel volume to cope with a higher fuel demand than the primary pump can supply?

The GP Packages have Fuel Pump 2 and Fuel Pump 3 available in them, these Pumps are switched based on Fuel Flow so you could have the primary supplying fuel to a set flow rate, and then when this is exceeded, Pump 2 turns on.

[Merlin]

Hi Stephen

The intention is to swap to reserve 5lt pot and pump when the fuel level in the Main tank area is exhausted

I will look at the Pump 2 and 3 functionality and see if it fits the purpose


The other car i have with a Auto reserve system just turns on the reserve pump with nominated pressure drop
IE logic of -normal fuel pressure is 300 kpa if rpm above 3000 and fuel press below 275 Kpa then turn on reserve pump

My thoughts are as the fuel pressure rises with boost i need to allow for this change

JP

[Stephen Dean]

Unless you have a rising rate fuel regulator, the differential fuel pressure (the pressure across the injector) should remain the same, I would be basing any operations on this pressure, rather than the rail pressure.

[Merlin]

Hi Stephen

Yes, the car has a rising rate Fuel Reg and it manifold referenced

This is just about tank fuel Level ...When the main tank runs low switch to reserve tank
As i have said normally i would use fuel pressure as my reference
but given its a turbo car with rising fuel pressure to match boost i was asking what others had done

I was hoping for a simple solution