The Cummins product line for 2007 features an emissions approach that’s little changed from 2002/04. It will continue to use its proven cooled EGR technology and variable-geometry turbocharger, the only additions being exhaust aftertreatment by way of a Fleetguard particulate filter and a crankcase ventilation system with its own filter. This is consistent on all Cummins on-highway diesel engines for
North America, including the heavy-duty ISX and ISM as well as the mid-range ISL, ISC and ISB engines. Ratings will be essentially
the same, with none removed for ’07.

A small change, though an important one, is the replacement and relocation of the existing EGR valve. As with all other engine makers, these valves proved to be the single most troublesome component in EGR systems. Now moved out of heat’s way, with a new design and manufacturer, that problem should be solved.

Cummins has some 300,000 EGR engines on the road, and they’ve racked up more than 30 billion miles of experience. Its 2007 field
testing is said to be well ahead of schedule, having started last May, and that even includes having ’07 engines installed in customer trucks on a normal assembly-line basis. Field testing has been extensive, and limited production is slated to begin in thje fourth quarter of this year.

The entire line features a single electronic control module that controls both engine and aftertreatment. All engines will use the patented Holset variable-geometry turbocharger, which features an electric actuator for 2007 with faster response and improved precision in adjusting air flow to the engine.

The particulate filter burns off soot automatically, invisible to the driver, though a manual ‘regeneration’ can also be done by simply
idling the engine for 15 to 40 minutes, depending on ambient temperature. The filter will have to be removed and cleaned of ash – by a special machine – every 200,000 miles or so, a process that will take about half an hour. Oil-drain intervals will not change for 2007, and fuel economy should stay the same too.