measuring fuel efficiency
in [Design]
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From: Joel Koltner on 12 Aug 2010 00:25 "Jim Thompson" <To-Email-Use-The-Envelope-Icon(a)On-My-Web-Site.com> wrote in message news:s2r666tikq13rei7psmgrmsslgakidgidm(a)4ax.com... > I think station pumps are quite accurate, at least in those states > that penalize heavily for inaccurate delivery... like AZ :-) Oh yeah, certainly the "gallons delievered" read-out is accurate... but if you're doing as Rich says (and this is what my parents taught me to do decades back), it relies on your filling your tank up to the same level as it previously was, and hence the question is how consistent are the auto-shut-off detection devices from pump to pump? (...this is why Rich says to use the same pump at the same station, to avoid this variation...)
From: Nial Stewart on 12 Aug 2010 06:01 > it takes time to stabilize because its needs a resonable amount of > data to average, > the instantaneous mpg is all over the place depending on wheter you > accelerate hard, > cruise at constant speed, go downhill in cut off etc. > you wouldn't want the average to show 10mpg just because you floored > it going on to the > freeway, same for the miles-to-go I can get average or instand MPG (Volvo V70) , the instant does go all over the place when you floor it. Nial.
From: Nial Stewart on 12 Aug 2010 06:03 > Oh yeah, certainly the "gallons delievered" read-out is accurate... but if you're doing as Rich > says (and this is what my parents taught me to do decades back), it relies on your filling your > tank up to the same level as it previously was, and hence the question is how consistent are the > auto-shut-off detection devices from pump to pump? (...this is why Rich says to use the same pump > at the same station, to avoid this variation...) This doesn't really matter as long as you finish at the same pump you started at! Nial.
From: Nial Stewart on 12 Aug 2010 06:06 > We have a tachometer, so would it follow that "squirts" are > proportional > to rpm, assuming 1 squirt for every two revolutions in a 4 cycle > motor. > Not sure though. > Ken It's not just the number of squirts but the squirt duration which is how the air/fuel ratio is controlled depending on engine speed, throttle position etc. It should be simple enough for the ecu to maintain a running total of injector on duration -> fuel used. Nial.
From: Michael Kellett on 12 Aug 2010 11:24
"Nial Stewart" <nial*REMOVE_THIS*@nialstewartdevelopments.co.uk> wrote in message news:8chv95Fto3U1(a)mid.individual.net... >> Oh yeah, certainly the "gallons delievered" read-out is accurate... but >> if you're doing as Rich says (and this is what my parents taught me to do >> decades back), it relies on your filling your tank up to the same level >> as it previously was, and hence the question is how consistent are the >> auto-shut-off detection devices from pump to pump? (...this is why Rich >> says to use the same pump at the same station, to avoid this >> variation...) > > > This doesn't really matter as long as you finish at the same pump you > started at! > > > Nial. > But if you finish where you started the mpg = 0/gallons :-) Michael Kellett |