By Dave Millhouser

It was nearing dawn and Bill was flopping around in the drivers seat, trying to keep awake. It was ye olden days and we didnt count "hours of service" -- it was DAYS of service. He glanced at the interior mirror ... and screamed.

Apparently, sneaking up behind him was an unkempt, unshaven man.

The bus swerved and there was a slight indication Bill may have dampened his seat before realizing the ugly apparition was himself. The mirror had slipped down and he was looking at his own mug.

History does not record his passengers thoughts.

Sometimes "preventative worrying" works, but too often we get stressed about things that never were a danger.

2010 is coming, and were girding for another round of engine changes.

Heck folks, if youre reading this, you survived 2002, 2007 and all the others. Youre gonna survive this one, too. Yogi Berra said it best: "This is like déjà vu all over again."

Most of the engine builders are using a new technology this time around. Selective Catalytic Reduction (SCR) will add new "stuff," weight and operational concerns. SCR chemically treats exhaust gases after their confused journey inside and about the engine.

Adding this step allows engine manufacturers to lower pressure and stresses inside the engine, as well as reduce the amount of cooling necessary.

Proponents point to better reliability, longer life and measurably better fuel mileage. Particulate filters will still regenerate, but less often. They hope to return engines to 1999 performance levels.

Detractors point out that SCR introduces a new system that adds weight, requires attention, and can break.

One engine builder is meeting 2010 requirements by tweaking its current EGR system.

Bus manufacturers, as in the past, have stocked up on as many 2009 engines as the current market conditions allow. Depending on what you buy, it may be months before youre forced into a decision.

SCR does add some operational steps. It works by spraying a minute amount of a urea-based liquid into the exhaust stream. Coaches will carry this "diesel exhaust fluid" (DEF) in a tank, along with a mechanism to spray it into a special chamber where it mixes with exhaust gases. Most of the tanks will be approximately 20 gallons, and a fill may last up to 7,000 miles.

In addition to filling the tank periodically, theres a filter to change. The DEF has some temperature constraints. Too cold and it freezes, too hot (for a long period of time) and it slowly turns to ammonia. Its an organic compound that a demented bus salesman once told me is a chemical cousin to pig urine.

This may sound complicated but it has been working successfully in Europe for years. Most diesel trucks in this country will use SCR/DEF (WAY too many acronyms), so infrastructure is on the way. If you send a coach on an extended trip there will be thousands of fuel stops and dealers that will sell DEF in bulk or jugs for an estimated $2.75-$2.80 per gallon.

Coaches will have DEF gauges or lights. There is clever programming that will not allow the engine to start once the DEF tank empties but wont normally shut down while under way.

A couple of things to consider while considering future coach purchases:

Aside from the normal startup hiccups, this stuff is likely to work fine, so its not worthwhile to buy extra buses now just to avoid it. (As if anyone can afford to do that right now.)

The best engine is STILL the one with the best local dealer. Talk to your engine folks now and see what they think. As in the past, all of these engines will be good but none will be perfect.

Service trumps almost everything. The engine builders all have websites that explain their systems.

Take a look at how the bus builders wedge the new stuff into their coaches; look for potential problems with the installation. Ask questions.

Driver training shouldnt be a big issue but they will have to know what the DEF gauge/lights mean, or youll get a call at midnight, asking why the bus wont start.

Look into your duty cycle. 2010 technology is going to add thousands of dollars to the cost of a coach, which may be recouped in fuel savings. If you are a high-mileage carrier, SCR technology might make sense sooner than for an operator that does more hours than miles.

FDR once said "We have nothing to fear but fear itself."

Probably appropriate here, but on this topic baseball immortal Satchel Paige may have been more on target: "Don't look back. Something might be gaining on you."

Dave Millhouser is a bus industry marketing consultant and freelance writer. Contact him at: dave_millhouser@hotmail.com.