t vago's MPGuino workspace thread, continued

[t vago]

Originally Posted by Ardent

The issue I've seen is parasitic drain during prolonged non-use. I thought perhaps there was a deeper sleep mode.

I try to remember to unplug it after the EEPROM write.

This idle mode may yet provide some savings. Current, when MPGuino goes to sleep, all it really does is display the system time and turns off the backlighting, also also stops transmitting serial logging /JSON data. Other than that, it still sits there and "spins its wheels" when it's not actually displaying or calculating things. Idle mode is intended to stop the CPU when MPGuino isn't required to do anything that resembles calculation, which is a surprisingly large fraction of the time it's powered up.

I am considering how to implement deep sleep mode, but you would lose the ability to wake up the MPGuino if you have 5-button analog switches or the Parallax switch assembly or buffered LCD. I might could work around buffered LCD, but analog/Parallax switch support is a show stopper.

I will likely end up making deep sleep incompatible with analog/Parallax switches. That is, you can have either one or the other, but not both.

Oh, and deep sleep would also be incompatible with the built-in clock display - the onboard clock would simply stop once MPGuino entered deep sleep.

Originally Posted by josemapiro

Hi t vago
Thanks for the correction, now you can make the change.
But in the settings when switching to the metric system, it does not change to Microsec/L.
The previous version also had the problem, but when I informed it, I checked that I already had a new version, I thought the new version would correct the problem, but no.

I actually gave up on autoconverting and storing that microseconds/gallon figure as a parameter, seeing as how all of the listed vehicles on the MPGuino Wiki listed their numbers as microseconds/gallon, and it would have led to more confusion once people started using Imperial gallons vs US gallons.

Besides, the number is already autoconverted inside the code itself. It just isn't stored as a parameter.

[josemapiro]

Hi t vago
When I speak in the metric system I am not referring to the imperial gallon, but to liters, which is the international norm "SI".
The MPGuino used to do the conversion before and it was all in liters when switching to the metric system, now it does not, it changes all the others to liters less microseconds/L, I think how it worked before, because it avoids converting liters to US Gallon.

Thanks
José Rodrigues

[t vago]

Originally Posted by josemapiro

Hi t vago
When I speak in the metric system I am not referring to the imperial gallon, but to liters, which is the international norm "SI".
The MPGuino used to do the conversion before and it was all in liters when switching to the metric system, now it does not, it changes all the others to liters less microseconds/L, I think how it worked before, because it avoids converting liters to US Gallon.

The code still correctly displays fuel consumption in liters, when metric mode is selected.

I took out the storing of microseconds/liter, because this unit is not used on the MPGuino Wiki page.

I did this because it would be confusing for people to list microseconds per US gallon, microsecond per liter, and microsecond per Imperial gallon. I decided that only one unit should ever be used, and since the MPGuino Wiki already uses only microseconds per US gallon, that is what I would also use.

I do not understand why this should even be a problem, since MPGuino can now calculate this figure directly from injector size and the number of injectors.

[josemapiro]

Hi t vago

Originally Posted by t vago

I do not understand why this should even be a problem, since MPGuino can now calculate this figure directly from injector size and the number of injectors.

What are the values that he uses to do this calculation.

Thanks
José Rodrigues

[Ardent]

Regarding deep sleep: like the positives, unaffected by the negatives.

[t vago]

Originally Posted by josemapiro

What are the values that he uses to do this calculation.

value = (number of fuel injectors) * (fuel flow rate of each injector, in cc/min)

value = value * sqrt( (vehicle fuel pressure) / (injector test flow fuel pressure) )

value = 1 / value

value = value * 3785 cc/gallon

value = value * 60 sec/min

value = value * 1000000 microseconds/sec

Originally Posted by Ardent

Regarding deep sleep: like the positives, unaffected by the negatives.

Yah, I kind of figured the same. Once I debug the accel test module, I'll work on adding deep sleep to the code.

[josemapiro]

Hi t vago

Originally Posted by t vago

value = value * sqrt( (vehicle fuel pressure) / (injector test flow fuel pressure) )

Knowing the first value, this value is not necessary correct.
If I need to, how do I get it?

Thanks
José Rodrigues

[t vago]

Originally Posted by josemapiro

Knowing the first value, this value is not necessary correct.
If I need to, how do I get it?

There are two stored parameters before the "# of cylinders" parameter.

The first is "P(Fuel)" and it can be in either psig *1000 or in Pa. The second is "P(Ref)" and it can also be in either psig *1000 or in Pa.

In the code I have attached at the beginning of this thread, I have both of those values set to 43500 psig * 1000, so that square root portion will evaluate to 1.

P(ref) should remain at 43500 psig * 1000, because that is the pressure that fuel injectors are normally flow-tested at, to get their flow ratings.

P(Fuel) is the fuel pressure of your vehicle, and should be set accordingly.

[josemapiro]

Hi t vago
It's great I had no idea it worked like that.
One change that I believe takes some confusion is in InjSize mL/min which could have an InjFlow text and use cc/min which seems to be more common in the specs of the injectors, what do you think.
Another question, the InjSize mL/min does not allow a decimal number in my case, the injector has a value of 191.8 cc/min, I have to put "192" correct.

Originally Posted by t vago

value = value * 1000000 microseconds/sec

I think you mean microseconds/USGal

Thanks
José Rodrigues

[t vago]

Worked over the timer scheduler a bit, toward the goal of enabling deep sleep mode. I estimate that I reduced the code's power consumption by anywhere between 20% and 40%, with a given configuration.

Originally Posted by josemapiro

Hi t vago
It's great I had no idea it worked like that.

I figured this would be a useful addition to MPGuino. That, along with some sort of calibration mode for both distance and fuel, would go far in making MPGuino more user-friendly.

Originally Posted by josemapiro

One change that I believe takes some confusion is in InjSize mL/min which could have an InjFlow text and use cc/min which seems to be more common in the specs of the injectors, what do you think.

Good idea. Done.

Originally Posted by josemapiro

Another question, the InjSize mL/min does not allow a decimal number in my case, the injector has a value of 191.8 cc/min, I have to put "192" correct.

Yes, that is correct. With the number you gave, and assuming 4 cylinders, the two values differed by about 3 million microseconds/USgal.

I may have to increase the precision of this injSize parameter, such as making the units cc/min * 1000.

Originally Posted by josemapiro

I think you mean microseconds/USGal

Nope.

step 1: value is in cc/min

step 2: value is in cc/min

step 3: value is in min/cc

step 4: value is in min/gal

step 5: value is in sec/gal

step 6: value is in microseconds/gal (value = value * 1000000 microseconds/sec)