Clearing The Air In 2010 With EGR Diesels Versus SCR - Or Not

Implications: The referenced article explains better than most on how Exhaust Gas Recirculation (EGR) can work in 2010 through emissions’ credit averaging, banking and trading. Several of us in the past in these missives have addressed this. One can’t technically get to 2010 levels on individual engines with EGR alone therefore requiring things such as Selective Catalyst Reduction (SCR), NOx absorbers or other approaches. The messages from the manufacturers will be fuel mileage v. heat v. how green v. ????

Analysis: With the Caterpillar / Navistar joint venture announcement effectively taking Cat out of the 2010 lineup, another hot topic has to do with Class 8 SCR versus EGR. Navistar’s complete line is EGR, while everyone else is going with SCR. Cummins is offering both.

EGR is being offered through the perfectly legal averaging, banking and trading scheme. It is similar to the auto industry CAFÉ (Corporate Average Fuel Economy) standards where some are worse than others - in this case dirtier than others - but it all comes out in the wash. And NO - carbon credits are a seperate issue. We will leave the moral / green questions out of this article for those who are already asking.

The main questions we are assessing include system costs, urea (ammonia) availability, fuel mileage and the heat-related issues. The questions include comparing 2007 compliance costs versus that for 2010 (with SCR). Discussions with OEM’s to date have shown that the major challenges / costs were incurred in 2007 with catalytic converters, filters, sensors and wiring. That additionally needed for 2010 SCR (tank, sensor, etc.) are small in comparison. As manufacturers move to more vertical integration and volumes, those costs are expected to be lower.

Urea availability is being discussed, but the largest US truck manufacturer (Daimler Trucks North America) has the partnership with Travel Centers of America and Petro Truck Stops for service outlets already in place to assist with the over-the-road segment. Flying J, Love’s, Pilot, etc. are also assessing their approaches. This will complement that being laid out through dealerships, etc. The expected Ultra Low Sulfur Diesel (ULSD) introduction problems (tanks, lines, etc.) never materialized - and the same is anticipated here.
 
The debate to come is when we see real numbers on fuel mileage on SCR versus EGR. Volvo and Daimler (Detroit Diesel) have said they expect to see better fuel mileage (up to 7%) with SCR. At $5 / gallon diesel, that is around a nickel a mile savings - and we will die for a couple cents. Confusing the issue will be the 13 versus 15 Liter engine issues, but 13 Liter SCR engines are the winners on paper today.

The other real point of contention is that regarding heat with costs estimated to add several cents per mile at today’s heat levels. Truck manufacturers continue to have a tough time in dealing with the underhood heat and see an opportunity to reduce that notably with SCR. EGR has benefits under certain conditions like light loads where heat rejection is also relatively low, so an EGR / SCR mix will be part of the solution - although with overall reduced EGR levels.

Which ever way one goes in 2010, it looks like the SCR direction (or something like it) will be more the answer longer-term - and once the emission credits run out. Regardless, the marketing, sales and service debate has also already started in earnest.