Revving up with a clean-machine lineup for 2007
Operators get more powertrain options

By now, most motor coach operators know that diesel engines are changing for 2007 to reduce emissions and help contribute to a cleaner world. MCI has long embraced the idea of cleaner coaches, but with the 2007 models, MCI has taken the required engine changes and run with them, making improvements to its models, too.

MCI is so far the only coach manufacturer to have built eight prototype models to test components related to new clean-diesel technology, and to have subjected a clean-diesel coach to the Altoona test. "The Altoona test is an accelerated lifecycle test," says Paul Fazio, director of powertrain engineering. "It's the equivalent of putting 100,000 miles or more on a vehicle."

One of the most important elements of the '07 engine package is the Diesel Particulate Filter, or DPF, which replaces the muffler componentry, and helps reduce particulate matter (black smoke). A regeneration process occurs to keep the DPF operating effectively. Testing has shown that approximately 85% of the time the DPF will regenerate passively.

"Each engine manufacturer differs in its strategy on active regeneration," said Fazio. "However, MCI has incorporated multi-stage alerts for the manual filter regeneration to provide sufficient notification for service technicians or drivers to perform active regeneration, for minimal interruption to trips."

High marks for the low-placed DPF

MCI has taken the approach of placing the DPF low. The advantages are many. MCI engineers were thinking about the welfare of the mechanic when they placed the DPF close to the ground. DPF filters weigh nearly 150 pounds, and by placing them low, technicians can work more safely, without a ladder or man lift. The placement also ensures that passenger and baggage room isn't affected. Plus, a sturdy skid plate helps protects the DPF against bouncing stones and other hazards of the road. Secure installation helps guard against theft.

More engine/transmission options

Other changes, too

MCI engineers took the clean-diesel opportunity to fine-tune a few other coach systems as well. "We've used this EPA-mandated change to improve our coaches in some significant ways," said Bryan Couch, vice president of product planning. "For 2007, cooling systems will offer more capacity, and the coaches will run more quietly. To accommodate the DPF, onboard diagnostics have been refined to alert drivers to DPF status. But that's not all. Says Fazio, "We've simplified the wiring connections and further standardized the wiring to improve reliability."

MCI has even improved the serviceability of the number-one-selling J4500 model and flagship E4500 by introducing a flip-down radiator and adding an engine compartment access panel. The D-Series rear cap has been redesigned as well, giving an overall sleeker appearance to MCI's classic workhorse model.

Smooth road expected

MCI expects that customers' clean-diesel engines will last about as long as their predecessors. And while there's a bit of a learning curve in adjusting to new service intervals and processes, overall, the new coaches shouldn't be more difficult to care for than earlier models.

"Clean-diesel coaches aren't new to us," said Couch. "Since 2002, we've equipped over 1,000 coaches for the public sector with DPF filters. They're up and running on ULSD, and the result has been positive. These clean diesel coaches have shown no measurable decrease in fuel economy, durability or reliability."

"The MTA has been very proactive in the use of Ultra Low Sulfur Diesel fuel," said Joseph (Joe) Smith, Chief of Operations, MTA Bus Company. "We currently have ultra low diesel in all the buses in New York City."  The agency has 440 of MCI Commuter Coaches in service that also use ULSD fuel and are equipped with DPFs that are easy to maintain, according to Smith.

The rules

The EPA has mandated a 90 percent reduction in particulate matter (black soot) and a 90 percent reduction in Nitrogen Oxides (NOX), (a contributor to acid rain), by 2010. This year marks perhaps the greatest shift toward that goal within the motor coach industry, as manufacturers start installing the clean-diesel engines required by law in their vehicles.

At the same time, oil companies have been reducing the sulfur in their diesel from 500 parts per million to the EPA-mandated level of less than 15 ppm. This new clean diesel is called Ultra Low Sulfur Diesel (ULSD). Most modern diesel engines can already run on this fuel; however, all vehicles with 2007 and later model clean-diesel engines installed will require it. The new engines will also require a new oil with reduced ash, known as CJ-4. The new oil is expected to be compatible with older engines as well so that operators will only have to stock one engine oil.

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