International Says New Diesels Can be 'Green'

MELROSE PARK, Illinois - International Truck and Engine Corp. (Navistar) displays its future "green diesel" technologies for financial analysts and the trade media here in the effort to change perceptions about diesel engines.

Internationl says it is confident its high-volume line of diesels for sport/utility vehicles (SUVs), pickups and medium-duty trucks will be able to meet the low federal oxides of nitrogen (NOx) levels proposed for 2007 - and also by then meet the particulate emissions levels proposed by the Environmental Protection Agency (EPA) and the California Air Resources Board (CARB) for 2010.

The company says this will be achieved with digitally controlled, hydraulically actuated rate-shaped direct fuel injection, hydraulically actuated engine valves, a deNOx catalyst and continuously regenerated particulate trap systems.

This "systems" approach is demon-strated with a medium-duty truck, fitted with the new combination of technologies, by placing a white cloth over the exhaust outlet as the engine runs. Nothing is visible on the cloth and there is no odor typical of conventional diesels.

But there is one additional requirement: diesel fuel must contain no more than five parts per million (ppm) sulfur, although one executive tells WAW that a minor deviation from this might be possible.

International explains that its hyraulically operated valves are actuated by roughly the same 3,000-psi oil pressure employed by the company's hydraulic unit fuel injectors (injection pressure is seven times higher at 21,000 psi). Engine oil is employed, not a separate hydraulic oil.

International says its hydraulic valves have 20 times more actuation force than electromagnetic systems. The high force is needed for diesels and provides even more precise control - including zero landing speed.

Advantages of the hydraulic valves include: variable timing, variable lift, variable compression ratio, multiple valve events and valve and cylinder deactivation.

The remarkably low noise of the new diesels is attributed to the digital hydraulic fuel injectors, which are able to provide five separate injections per cylinder during each combustion cycle.

International's diesel engine and parts sales have increased from $743 million in 1991 to $2.6 billion in 1999. It sold 384,000 diesel engines in the 160-hp to 300-hp class in 1999, better than 50% more than its nearest competitor.

Although International says its volume diesels will employ all the new technology elements by 2007, it indicates that elements of the system will begin to phase in sooner, but does not provide initial launch dates.