[AT] Ram fuel mileage

[Steve W.]

Stephen Offiler wrote:
> 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
> 

Here's hoping that they have this one worked out better than most of the 
rest. Most of the DEF trucks I deal with are a PIA. Codes due to the DEF 
being "low quality" even when it's NEW factory stock. Regen shutting 
down the engine while driving. Low power mode due to a phantom issue. 
And my favorite, random engine shutdowns while going down the road...


-- 
Steve W.