On the stimulator all seems to work well, but when TS hooked up in the car the gauge shows realy low value's which would be very nice if the figures are correct. That should mean i have a fuel economic car.
While driving around at a constant 80kph the gauge shows 4 liters/hour , which means "20km/l" or "5L/100k". My car could never be that economic, it has never done better as "10km/l" average in the old days when it was running on a 4 barrel carburettor. Its running Megasquirt MS 2 for a few weeks now.
After a 50km logged run, the log tells me the engine has consumed 2.83 liters of fuel, which means 5.66liter/100km or 17.6km/l. i know for shure it consumed more. (a lot more)
This is what i've added in my custom.ini in my project:
Code: Select all
[GaugeConfigurations]
gaugeCategory = "Custom"
FuelFlow = fuelFlow, "Fuel Consumption", "Ltr/Hour", 0, 50, -1, -1, 20, 30, 2, 2
[OutputChannels]
maxFuel = { (staged_pri_size/1000)*nCylinders*60} ,"L/H" ; FuelFlow @ 100% dutycycle (injector size(L/min) * Nr cylinders * 60 minutes)
fuelFlow = { (pulseWidth1 > 0) ? ((100.0*nSquirts1/altDiv1*(pulseWidth1-deadtime1)/cycleTime1)*(maxFuel/100)) : 0 }, "L/H" ; if pulsewith > o then calc netto duty cycle, actual time injectors are open,* maxFuel/100%
[Datalog]
entry = fuelFlow "Fuel Flow", float, "%.2f"
Then i've defined the 'fuelFlow' value, which is derived from the dutycycle, only taking the deadtime in account to. When changing the deadtime in TS, the Fuel consumtion stays unchanged, tested this on stim.
The 'fuelFlow' output value is also logged.
i've 6 HighZ Bosch 0-280-150-716 injectors on my car which have a fuelflow of 134cc/min@3bar, on the fuelrail is a 2.5Bar pressure regulator (checked the pressure), so real fuelflow should be 122cc/min.
In TS the injector size = 130cc/min (should be 122, but then i should get even lower fuel consumtion figures)
This means that maximum fuelflow (100% dutycycle) should be (130cc*6inj*60min)/1000=46.8L/H
I'm running semisequential injection with 3 injector drivers, this means each injector fires each engine revolution. (twice each engine cycle)
When running on the stim revving 6000RPM and MAP=100KPA i've a dutycycle 80% and the Fuel Consumtion gauge shows 33.7L/H, which seems OK !(pulsewidth = 8ms, deadtime = 0.832ms, 1 engine rev=10ms)
When running on the stim revving 3000RPM and MAP=50KPA i've a dutycycle 16.8% and the Fuel Consumtion gauge shows 5.9L/H, which seems OK too!(pulsewidth = 3.35ms, deadtime = 0.832ms, 1 engine rev=20ms)
Recalculations give the same figures. recalculating the last example:
- real injection time = 3.35 pulsewidth - 0.832 deadtime = 2.518mS
- all injectors are 6*2.518mS=15.108mS /revolution opened
- engine does 50 revs/second (3000RPM/60S)
- so all injectors together are 50RPS*15.108mS=755.4mS open per second
- so all injectors together are 60S*755.4mS/1000=45.324seconds/minute opened
- this means all injectors are squirting (45.324/60)*130cc=98.202cc/min
- this gives 98.202cc/min*60min/1000=5.89liter/hour fuel consumption. same as TS is showing.
I do not understand why tunerstudio gives low fuel consumption figures while driving aroud, as the car uses more fuel for shure
By the way, the car (BMW E12 with M20B20 engine) runs great on the MS2