[AT] Ram fuel mileage

Stephen Offiler soffiler at gmail.com
Fri Jun 13 07:36:58 PDT 2014


Most of the diesels available new in the USA are using DEF (that is Diesel
Exhaust Fluid and is the common name for the urea that Spencer mentioned).
 There are some exceptions in the VW TDI lineup.  It's all a matter of
meeting the US emissions specifications.  If they can tune (or detune) the
engine to meet emissions without DEF, then they might choose that route.
 For example, VW detunes the Jetta TDI and omits DEF, resulting in slightly
lower fuel economy versus the Passat TDI which does use DEF.

DEF controls oxides of nitrogen, not particulates.
http://en.wikipedia.org/wiki/Diesel_exhaust_fluid

Yes, the new Ram Ecodiesel engine requires DEF.  Ram claims 11 gallons per
10,000 miles which is 909 miles per gallon DEF. Some Internet forum
discussion reports actual consumption rates slightly above 1000 miles per
gallon DEF.  1000 is a nice round number.  NAPA sells 2.5 gallon jugs for
$14 (= $5.60 per gallon DEF) but it is starting to show up at gas stations
for reportedly as little as $3 per gallon DEF. Let's just call it a nice
round $5 per gallon.  That's an additional expense of $5 per 1000 miles on
top of fuel cost.  At 25 MPG and $4 per gallon for fuel, it costs $160 for
fuel to drive 1000 miles, so just make that $165.  If you were to think of
DEF like some sort of fuel surcharge, it works out to 3%.

As a side-note, particulates are controlled with a Diesel Particulate
Filter (DPF) which is built sort of like a catalytic converter but it
doesn't do any catalyzing.  It traps the particles and then periodically
heats WAY up (650C plus, which is 1200F plus) to burn the collected
particles down to ash.  This is called DPF Regeneration.  It will happen
naturally if you drive hard enough to get it that hot; otherwise it will be
forced to happen periodically (about every 500-1000 miles) by injection of
extra fuel.

SO





On Fri, Jun 13, 2014 at 9:08 AM, Spencer Yost <yostsw at atis.net> wrote:

> One side note.  The diesel they build for the Chevy Cruz American market
> uses urea injection for particulate control.    The urea tank is just
> another tank to fill and eliminates the spare tire.   They give you a can
> of fix-a-flat instead!
>
> Not sure about about the larger engines.   I was only looking at cars.
> In the end my wife decided to keep her VW diesel jetta (fuel is used for
> particulate control) and run it into the ground.  Which is proving hard to
> do (-:
>
> Spencer
>
>
>
> Sent from my iPhone
>
> > On Jun 13, 2014, at 0:55, "Sewell, Steven" <sewell at ohio.edu> wrote:
> >
> > Dennis keep us updated on the truck. The same diesel is an option in the
> Jeep Grand Cherokee.  I've been looking at the Jeep for our "car"
> replacement in the next year.
> >
> > Steve Sewell
> > Albany, Ohio USA
> > sewell at ohio.edu
> > sewell at atis.net
> > ________________________________________
> > From: at-bounces at lists.antique-tractor.com [
> at-bounces at lists.antique-tractor.com] On Behalf Of Dennis Johnson [
> moscowengnr at yahoo.com]
> > Sent: Thursday, June 12, 2014 12:56 PM
> > To: at at lists.antique-tractor.com
> > Subject: [AT] Ram fuel mileage
> >
> > All,
> > The mileage numbers were calculated after entering gallons and miles
> into a spreadsheet. I also did trip average for the long trips via
> spreadsheet. I also do a running 3 tank average to check for incomplete
> fill ups, etc.
> > I do not have a good way to account for idle time, etc. truck records
> idle vs drive time, but not sure exactly what to do with this other than
> keep for general information.
> > I am guessing the screen numbers on the dash are a little bit high, but
> still impressed with the truck.
> > Thanks
> > Dennis
> >
> >
> > Sent from my iPad
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