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Input variables where Inj_out is dependant of...
As my car will be running on Vapourised LPG injection my Inj_output timing will be dependant of Fuelpressure and Fueltemperature. I already have a sensor mounted that's able to collect these values.
Connect the signal to free ADC inputs - mcp3208. Check the shop text for free inputs. Apparently
- EC18pin12 available ADC because secondary_trigger: HALL
- EC18pin6 available ADC because onboard MAP
- injection pulsewidth calculation
- do some research for the formulas. Make tables and examples (octave,matlab, spreadsheet?). You can try to make final functions using +,*,table_lookup operations. Division only with power of 2 (/2, /4, /8... /256, /512 ...)
- I guess the fuel pulsewidth needs a *1/sqrt(fuel_pressure) multiplier (we'll likely use a table for sqrt() for speed.
- I have no idea how the fuel temperature will be used. Most likely another table_lookup for viscosity ? ( --- I don't think viscosity of a gas varies much with temperature. Density does , by universal gas laws ; multiply calculated fuel amount by T/Tref - both in degrees K - to correct for that.)
When the plan is ready, we'll add to the firmware and make it possible to enable it in config.
LPG needs some extra analog inputs to work
I want to run fully sequential injection and ignition with and Hall sensor as secondary trigger.
- secondary trigger is HALL => EC18pin12 available analog input
- onboard MAP sensor => EC18pin6 available analog input channel
- no 1-wire => EC18pin16 might be available analog input channel (added recently)
It seems no need to alter the hardware of my genboard to use it with Vapourised Sequential LPG Injection.
Fully sequential is configured in config (the EC36pin13 is only used for cam-HALL, not normally reused for other tasks anyway).
software:
From what I understand you need 4 look-up tables:
- Fuel_temp : Vsens_out
- Fuel_pressure : Vsens_out
- Fuel_temp : Density
- Fuel_pressure : Density
What is Vsens_out for ?
- I can configure these tables in excel if you want. The values will be between: 0.25V and 4.85V.
- sounds like a good start. I recommend 1/density (not density), try to make a linear formula to have table values in 0..255 range.
For the Fuel_pressure Vsens_out can be calculated: as Vout=(c1*Pabs+C0)*Us. This need no table, if the required variables are available.
Vout = signal output voltage in V
Vs = supply voltage in V
Pabs = absolute pressure in kPa
C0 = -5/350
C1 = 0.8/350 kPa ^-1
- I'll get you an excel sheet asap. Have you got an email adres I can send them to?
- What does the original code looks like to calculate Injector pulsewidth ?
- Can you explain the devisions a bit more? As i'm not a software engineer I don't understand these terms.