Government Diesel Emissions Standards & RV's

I just returned from the Pennsylvania trade/public RV1) SCR gives you 5% to 8% better fuel economy.
show and while looking at a new motorhome on a2) More torque & horsepower compared to a similar
Freightliner Custom Chassis I noticed what looked to2007 engine with Exhaust Gas Recirculation (EGR)
be a small fuel tank located under one of the outsidetechnology.
storage compartment doors. The cap on the tank hadCons:
the letters (DEF) which I later discovered stands for1) The owner will need to keep the DEF tank topped
Diesel Exhaust Fluid. I had no idea what Diesel Exhaustoff. The word is that DEF will be abundantly available
Fluid was, so I headed over to the Freightliner displayat travel centers & auto parts stores.
to find out. The Freightliner representative was2) It is possible for the DEF solution, made up of
extremely knowledgeable and helpful in explaining whattwo-thirds part water, to freeze. The word is the DEF
DEF was, and after returning home I decided totank is insulated and the system uses heated lines to
research it a bit further.deliver the fluid to help avoid freezing.
It turns out DEF was a result from the latest rounds of3) DEF can degrade, but it would take 125 degrees of
EPA mandates on diesel engine emissions standards.direct heat over a period of time, which is unlikely to
These EPA mandates on diesel emissions have a longever happen.
history. For over 25 years the EPA has aggressively4) If for any reason you do not fill the DEF tank and
increased stringent diesel exhaust emissions standardsyou run out the engine will decrease speed to
on manufacturers, most notably in the areas ofapproximately 30 mph until more DEF is added to the
Particulate Matter (PM) and oxides of nitrogen (NOx).system again. There are gauges in the coach that will
These exhaust emissions are by-products of thealert you in plenty of time to refill the tank before it
combustion (or incomplete combustion) of diesel fuel.runs dry.
Think of the PM as the soot or smoke you see5) Increased cost. The new technology is sure to
emitted from the exhaust system. Oxides of nitrogenaffect pricing, but the jury is out on whether the
result from a bad reaction between nitrogen andprojected increased fuel economy will offset the
oxygen in the high temperatures created by theincrease in price over a period of time.
combustion process.So like it or not, this is the system of choice being used
In 2000 the EPA signed emissions standards aimed atby the majority of RV manufacturer's to meet or
PM emissions, designed to take full effect by theexceed the 2010 EPA diesel emissions standards.
release of 2007 model year vehicles. That brings usWhat's next?
back to DEF and the 2010 EPA mandates, designed toGet ready for the next round of EPA mandates. Now
reduce the amounts of nitrous oxide emissionsthat the exhaust coming out of the tailpipe is probably
released into the atmosphere.cleaner than what is going into the intake (in many
As far as the RV Industry goes all but one Originalareas of the country) we need to brace ourselves for
Equipment Manufacturer (OEM) chose a processwhat is next. It looks like the next government
called Selective Catalytic Reduction or (SCR) to meetapproved EPA and DOT mandates are aimed at
this new EPA standard. Simply put SCR adds a Dieselincreased fuel economy and Greenhouse Gas (GHG)
Exhaust Fluid and a catalyst that is designed toemissions. These new diesel emissions standards will
remove additional PM and emissions from the dieselbe phased in between 2014 and 2018.
combustion process.The new standards being imposed are sure to
Pros & Cons of SCRdramatically increase the cost of a diesel powered
So what does all of this mean to the new diesel RVmotorhome again, and the question begs will the ends
owner?justify the means?
Pros:You be the judge.