Hi, I'd like to add instantaneous fuel efficiency (MPG - miles per gallon) to OBD Gauge for Palm. I've only been able to find a single mention of how to calculate this from an article at Circuit Cellar http://www.circuitcellar.com/adverti...ghtner-183.pdf .

There, Bruce Lightner gives the formula:

MPG = (14.7 * 6.17 * 4.54 * VSS * 0.621371) / (3600 * MAF / 100)

= 710.7 * VSS / MAF

MPG - miles per gallon

14.7 grams of air to 1 gram of gasoline - ideal air/fuel ratio

6.17 pounds per gallon - density of gasoline

4.54 grams per pound - conversion

VSS - vehicle speed in kilometers per hour

0.621371 miles per hour/kilometers per hour - conversion

3600 seconds per hour - conversion

MAF - mass air flow rate in 100 grams per second

100 - to correct MAF to give grams per second

Is this what other software uses to calculate MPG? Are there other methods?

I just got my OBD2 All-In-One yesterday, and have just started playing around with it and OBD Gauge. I'm going to try and add the above formula to OBD Gauge and see what it gives. I'd really appreciate any info. Thanks

There, Bruce Lightner gives the formula:

MPG = (14.7 * 6.17 * 4.54 * VSS * 0.621371) / (3600 * MAF / 100)

= 710.7 * VSS / MAF

MPG - miles per gallon

14.7 grams of air to 1 gram of gasoline - ideal air/fuel ratio

6.17 pounds per gallon - density of gasoline

4.54 grams per pound - conversion

VSS - vehicle speed in kilometers per hour

0.621371 miles per hour/kilometers per hour - conversion

3600 seconds per hour - conversion

MAF - mass air flow rate in 100 grams per second

100 - to correct MAF to give grams per second

Is this what other software uses to calculate MPG? Are there other methods?

I just got my OBD2 All-In-One yesterday, and have just started playing around with it and OBD Gauge. I'm going to try and add the above formula to OBD Gauge and see what it gives. I'd really appreciate any info. Thanks

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