[Eric H]

Hi,
For our race car it would be nice to have the total seconds of injector open time since the last ECU boot.
Knowing how much fuel we've burned is essential so we don't run out on track. The in-tank fuel gauge is useless on track due to fuel slosh.
Knowing the total injector open time to the second is fine, that's plenty of precision for a fuel burn gauge.
I was planning to add a microsecond accumulator in the injectorNOpen() functions to add the PW - inj_open time, and in the main loop check to see if it's over a million and increment the seconds counter, then subtract a million from the us counter.
It'll be up to the user to convert injector open time to units of their choice.

Does anyone have any comments or requests before I implement this?

Also, there's some latent bugs in the main loop regarding the pulsewidth calcs.
Inside the PW() function there are clamps to limit pulse length for the hardware, then in the main loop it then adjusts them with no overflow checks before clamping it to the duty cycle limit. This could lead to some lean conditions at very low RPMs.

[PSIG]

TunerStudio can have a fuel consumption gauge set-up, but it's not cumulative. Not sure if you could do that. You concept is OK, though we fixed a similar fuel gauge issue when upgrading to stepper gauges by controlling signal cumulative averaging. Not that you couldn't use Speeduino, but installing an Arduino (we used ATTiny) inline to your gauge and averaging thousands of readings over seconds to minutes could give you are reasonably reliable fuel gauge reading in many applications. Just an idea to improve the vehicle's gauge readings to a useful level.

David

[Eric H]

David,
Unfortunately not.
Our dashboard has been a ST407 based LCD unit for over five years.
I've tried many different filtering algorithms and none of them are any use when the car is moving.
I've gone all the way to an eighth order .033Hz filter and the output was still garbage.

The rules we race under do not allow us to modify the stock tank. Due to fuel slosh in the stock unbaffled tank, the sensor goes between 0% and 100% almost randomly. I've got the logs somewhere.

The only solutions are put flow sensors on the pump output and rail return lines and subtract them ($$$$), or get the ECU to tell me how much fuel has been injected. Since I'm a software guy getting the ECU to tell me what I need seemed like the logical choice. It's also free.

If I could upload a picture I'd show you what the dash looks like.