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Old 08-12-2011, 06:35 PM   #9
Geek OP
oot & aboot
 
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Joined: Jun 2003
Location: 8000ft, Twin Spruce Gap, Colorado
Oddometer: 29,667
Bluetec

"Dude! Yer van runs on PeePee!" -Wolfman (yeah.. the owner of Wolfman luggage)

Bluetec is an "interesting" technology.

Executive summary: I have to keep the PeePee tank full or the van won't run

The good:
-It allows them to up the compression on the diesel engine and get better performance/gas mileage.
-ULEV status (ultra low emmissions)

The bad:
-complexity
-You have to fill up the AdBlue tank (which isn't cheap ).
-AdBlue is 33% urea (urine) so it allows your buddies, like Eric, to tease you

paraphrasing wikipedia:

The BlueTec system was created because the processes that give diesel engines efficient fuel economy also creates extra emissions of certain pollutants. High compression ratios and lean air-fuel mixtures make high combustion temperatures, which results in more nitrogen oxides being released into the atmosphere. While the particulate matter can be controlled with higher injection pressures and particulate filters, the big challenge is limiting NOx

Consisting of many different elements, BlueTec most notably relies upon particulate traps to eliminate soot/smoke throughout the engine's operating range, and upon urea injection from a stored canister (Mercedes calls this AdBlue) into the exhaust stream. AdBlue injection begins a chemical chain reaction which, in conjunction with an additional catalytic converter, converts nearly all remaining NOx into water vapor and nitrogen.

What it means from an owner's point of view:

The van carries 5 gallons of AdBlue on board. This is good for somewhere around 8000 miles.
When it gets down to 2 gallons left it'll warn you.
When it gets down to 1/2 gallon of AdBlue it will let you start the engine something like 20 more times before it disables the vehicle.

Moral: keep some adblue with you.
I already went and bought a couple of cases.

It has all kinds of sensors to keep track of the system.. (you can't dilute it with water.. or pee in the tank.. I asked ).
The van can get upto 1800 miles per gallon of Adblue.

The cheapest I've seen Adblue is $9 per half gallon (i.e. $90 per 5 gallons).

You have to be very, very careful when filling the adblue.. if you spill it it will crystallize and eat things like wiring, etc

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