Urea injector (inside exhaust pipe) and injection control slave mounted on Mercedes-Benz engine.

Editor’s note: This is the third in a series of articles on what to expect from 2007/2010 engines, in terms of maintenance, durability, fuel economy and overall cost.

With a little more than a year to go before the next round of emissions regulations kick in, the technology and engineering path for 2007 heavy-duty diesel engines is becoming clear. That doesn’t mean, however, that everyone is happy and comfortable. As we have been reporting, fleet managers are concerned that:

• The new engines will use a diesel particulate filter (DPF), which won’t be cheap and will require periodic maintenance to prevent performance and fuel economy losses due to exhaust backpressure. Another worry lies ahead for operations requiring active regeneration (see “Trapped!” page 54).

• ’07 engines will use higher levels of exhaust gas recirculation (EGR), except for Caterpillar’s, which will use a second-generation of its Advanced Combustion Emissions Reduction Technology (ACERT) with Clean Gas Induction (CGI) – a lower-volume EGR system in which the exhaust gas is drawn aft of the DPF. This likely will mean even higher underhood temperatures in most cases.
• Ultra-low-sulfur diesel (ULSD) fuel must be used, since combustion of sulfur creates particulate matter, which can poison DPFs. The new fuel will cost more and likely will have fewer BTUs than current fuel, thus causing increased consumption at a time when fuel prices already are at record levels. Moreover, depending on geographic area, the fuel still may not be available for some fleets who would like time to test the engines.
• A new engine oil, code-named PC-10, must be used, since the ash found in today’s oils can plug DPFs. And it will have to be more resistant to thermal breakdown, since ’07 engines will run hotter. However, the new oil isn’t scheduled to be available until mid-2006.
• And, finally, there aren’t many ’07 test engines to go around, and many fleets will have to wait until sometime in ’06. And some of those with engines don’t have the right fuel (see “Testing slowly gears up,” page 56).

With the exception of the ULSD fuel, which everyone will be using regardless of engine, carriers could postpone many of these worries with a pre-buy, although most agree that for the industry as a whole, a pre-buy is harmful (see “Mulling over a pre-buy,” below.) But even as questions remain about 2007, an announcement by one major engine manufacturer concerning the 2010 round of emissions and technology changes has many in the trucking industry already talking.

SCR for 2010?
EGR, ACERT and DPFs will be used to meet ’07 emissions regs. But another technology once considered as a possible solution for ’07 may become a key method of meeting even more stringent 2010 regs.