September 26, 2007 Vol. 3, No. 20

After a few weeks with not so much happening out there in product land, the last couple have been full of interesting developments, not least of which was a very big one from
Cummins. The engine maker finally announced what I’d been expecting, that its 2010 heavy-duty engines won’t need a little tank of urea to feed a selective catalytic reduction
(SCR) system. In fact, meeting the stringent 2010 nitrous-oxide emissions limits won’t demand any other form of NOx aftertreatment either. Many truck operators will consider this a big advantage, not having to keep a urea tank full.

Dr. Steve Charlton, Cummins executive director of heavy-duty engineering, says the ’10 engine will be an evolution of the existing ’07 product, employing “next generation” cooled
exhaust gas recirculation (EGR), a variable-geometry turbocharger, advanced electronics, and a diesel particulate filter (DPF). Not the same engine in every respect,

but a variation on existing themes, so there’s no added complexity. Cummins says power, torque, fuel economy and maintenance intervals will stay the same.

“We’re confident that we can hold the line on fuel economy,” Charlton said.

It’s long been assumed that SCR would be needed to meet stringent 2010 NOx limits, though Cummins has been hinting more and more obviously in the last year or so that
in-cylinder means could possibly be employed. It has also said repeatedly that its 2010 solution would be devised with customer needs at the top of the priority list, that it would devise the right technology to fit.

Speaking at a press conference in Nashville prior to the fall meeting of the Technology and Maintenance Council, Charlton also said the company will introduce two new
displacements, at 11.9 and 16.0 liters, to complement the existing 15-liter ISX engine.

The three will be referred to as the ‘X’ range and will share common architecture, though the new 11.9 will actually be derived from an all-new 13-litre diesel being developed for the Chinese market. The present ISM engine will be phased out in 2010 for North American on-highway markets but will continue to be sold elsewhere. The 16-liter size will
provide the displacement required to make EGR work at higher horsepower ratings.

Cummins medium-duty engines, unlike their big brothers, will use SCR as their NOx-reduction system for 2010, on top of cooled EGR and a DPF. It’s not new technology to the Indiana company, which launched its European mid-range engines certified to the Euro 4 standard using SCR in 2006. It’s the right technology for mid-range engines, Charlton says, in part because of the widely diverse applications in that world.

Both Detroit Diesel and Volvo/Mack have long since committed to SCR in 2010, while Caterpillar and others have yet to announce their plans for mid-range or heavy-duty motors two years from now.