MELROSE PARK, IL – Patrick Charbonneau will tell you that the key to future medium-size diesel engine designs is something of a paradox – improving horsepower, torque and fuel economy, while reducing the engine's size and weight. That's been the driving force behind International Truck & Engine Corp.'s development of the new 6.0-liter version of its Power Stroke diesel engine.

The evolution of this engine, Charbonneau told Fleet Owner, started around 1997, when International recognized the customer's desire for horsepower and torque also included better fuel economy. As vp-engineering for the engine division, it fell to Charbonneau and his team to not only figure out how to meet those somewhat conflicting needs, but make the engine emissions-compliant as well.

Another issue revolved around production, as International wanted to stick with conventional materials so the cost of building these engines, and the retail price, didn't go through the roof.

The 6.0-liter Power Stroke is a V-8 direct-injection 32-valve diesel engine, built around a newly designed cast-iron block, new cylinder heads and conventional aluminum pistons. A critical new component is the EVRT turbocharger, designed to improve acceleration, grade climbing capability, high altitude performance, and towing power over a wider range of engine speeds. In essence, the EVRT acts as a small turbo for faster response at low speeds and also like a larger turbo when more airflow is needed at full engine power, Charbonneau said.

Power Stroke produces 325 hp. and 550 ft.-lbs. of torque yet provides 10% better fuel economy and 20% lower exhaust emissions, plus far lower noise output, than its 7.3-liter big brother. It will be available in mid-2003 on Ford Motor Co.'s line of medium-duty trucks, heavy-duty pickups and SUVs.

The new engine also comes equipped with a cooled EGR system for emissions control, reducing NOx emissions to comply with more stringent EPA rules that go into effect October 1. Power Stroke also contains a second-generation G2 electro-hydraulic low-pressure common rail fuel system, using precision digital controls to more completely mix fuel and air in the combustion chamber, thereby simultaneously reducing both emissions and fuel consumption.

"The EGR system provides us with a platform to take us into 2007, but there are still a lot of unknowns ahead," Charbonneau added. "As we get into 2007, the characteristics of the G2 fuel system and engine control system will evolve to help meet the lower emission standards of 2007."