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mluckham · 07-27-2010, 01:43 AM

I've used the MPGuino for over a year. I've done nothing to the vehicle to add farings/etc but have realized almost 10% fuel efficiency improvement by running the tires at 35+ PSI rather than 25-28.

My vehicle has a characteristic 'best' fuel economy (6.2 L/100km) which is eventually reached given a long enough trip - on golden trips it has been 5.8 L/100km (!), but often it won't go below 6.5 L/100km - and these on the same trip and the same roads, just different days - why?

Watching the Instant readings fluctuate (and being a pilot) I've often thought about the wind resistance of the vehicle - which (besides the vehicle profile) is a function of air density (temperature, pressure, humidity) and headwind component. It would be interesting to be able to obtain a "current air resistance" reading from the MPGuino. Perhaps airspeed is sufficient, comparing that to ground speed from the VSS. Air density is easily calculated given the proper sensors, headwind component (airspeed) with more difficulty with some sort of aircraft-type pitot tube. I've was experimenting with pressure sensors a few months ago.

Does anyone have any comments about this idea?

07-27-2010, 01:43 AM	#1 (permalink)
mluckham EcoModding Lurker Join Date: Feb 2009 Location: Ontario, Canada Posts: 35 Thanks: 2 Thanked 14 Times in 7 Posts	Air Density I've used the MPGuino for over a year. I've done nothing to the vehicle to add farings/etc but have realized almost 10% fuel efficiency improvement by running the tires at 35+ PSI rather than 25-28. My vehicle has a characteristic 'best' fuel economy (6.2 L/100km) which is eventually reached given a long enough trip - on golden trips it has been 5.8 L/100km (!), but often it won't go below 6.5 L/100km - and these on the same trip and the same roads, just different days - why? Watching the Instant readings fluctuate (and being a pilot) I've often thought about the wind resistance of the vehicle - which (besides the vehicle profile) is a function of air density (temperature, pressure, humidity) and headwind component. It would be interesting to be able to obtain a "current air resistance" reading from the MPGuino. Perhaps airspeed is sufficient, comparing that to ground speed from the VSS. Air density is easily calculated given the proper sensors, headwind component (airspeed) with more difficulty with some sort of aircraft-type pitot tube. I've was experimenting with pressure sensors a few months ago. Does anyone have any comments about this idea?