Clearing the air on new particulate filters

You may not own a coach with a diesel particulate filter, or DPF, yet, but if you're an operator, you will. And chances are, you'll come to appreciate this technology not only for its major benefits to the environment, but also for its minimal impact on your operation.

Effective late July, all coaches rolling off the MCI production line have new, EPA-compliant engines that exclusively use Ultra Low Sulfur Diesel and depend on DPFs to all but eliminate "black soot" emissions. With almost any new technology comes a bit of a learning curve, but the DPF is a relatively quick study.

Each of MCI's three engines is a little different. Your owner's manual will be your best guide for detailed information (and look for additional training materials and seminars from MCI) about your DPF, which replaces a more familiar exhaust system, but there are a few things all operators should know:

The MCI difference is in the details
There's been a lot of talk about how different manufacturers have chosen to mount and incorporate their DPF filters, and why. MCI chose to mount its DPFs low on the coach, in a manner that doesn't intrude on revenue-generating space. MCI also believes that the low placement makes the DPF easier to service; shields should effectively protect it from normal road debris, and any additional heat generated is directed away from vital systems with thermal blankets.

DPFs are proven technology
Some transit fleets have already been using DPFs for several years now, and the reviews have generally been positive. As to MCI coaches with DPFs: "People have been a little apprehensive of the new technology, but it's being well accepted, and I haven't heard anyone complain about the DPFs," says Aaron Woods, MCI fleet support engineer.

Performance does not seem to have suffered much, if at all; MCI's own tests have shown that fuel economy has been the same or better on the new coaches compared to a 2006 benchmark coach, and may actually improve with some EPA-compliant powertrains. Maintenance is fairly easy, once you get used to a few minor changes.

Some things stay the same
There's no need to alter your pre-trip inspection ritual for the DPF — just make sure fluids are topped off as usual. Most of the oil- and filter-change intervals are the same as well. Again, see your Owner's Manual for details.

Fuel your green ambitions
ULSD fuel is absolutely required with the new '07 engines, and it's becoming increasingly accessible in both Canada and in the U.S. Check your engine manufacturer's specifications and the latest MCI Service Bulletins before using bio-diesel blends. Current specifications are that you use a maximum B5 (five percent bio, 95 percent ULSD) blend in the new Detroit Diesel engines and a maximum B20 blend in Cummins ISM engines. Bio-diesel blends have not yet been approved for the 2007 CAT engines.

Talking about my regeneration
One of the biggest differences in dealing with the DPF is the need for regeneration, the process by which most collected soot is processed. About 85 percent of the time, regeneration will be passive — in other words, it just "happens" as your driver drives. At other times, your driver will be prompted by new telltale lights (see accompanying "Maintenance Matters" story for details) to activate DPF regeneration while driving; he or she will need to maintain a speed of over 5 MPH for this to be successful. Finally, it may occasionally be necessary to conduct stationary (parked) regeneration, which takes about 20 to 40 minutes; because of the heat involved, the operator should heed all instructions about maintaining a safe distance, but should also stay with the coach during this time.

Some soot will remain anyhow. DPFs will need to be serviced every so often — for heavy duty applications, the average mileage service interval is estimated to be 150,000 miles.

Get a lift
Weighing in at approximately 150 pounds, DPFs are heavy! If you will be removing the DPF for service or replacement, your technicians should take extra care. Another key component in the system is the insulation blanket, which guards the rest of the coach against temperatures that can reach 1200° Fahrenheit during regeneration. Make sure your technicians familiarize themselves with its proper placement.

Enjoy
Finally, don't look at the DPF as a burden. Embrace it as your opportunity to contribute to a better, cleaner world. As we say: Go Green. Go Coach. Go MCI.

The FYI from MCI editorial staff values your feedback. Please e-mail any suggestions, comments, or ideas for future articles to fyi@mcicoach.com.