Mack Trucks has announced that it has achieved a breakthrough in engine technology to meet the special demands for the vocational truck market in meeting the requirements of the Environmental Protection Agency’s emissions regulations going into effect in October 2002.

The foundation for Mack’s EPA ’02 solution is a new platform of diesel engines, known as the Application Specific Engine Technology (ACET) family, which are engines on exhaust gas recirculation technology as the basis for emission reductions. The company has actually developed two engines. One, C-EGR, is designed as highway specific, while I-EGR is aimed at the vocational market.

Mack said its I-EGR was created to meet harsh vocational operating conditions. The breakthrough came from studying the typical operation of a vocational vehicle that often performs in a stop-and-go manner over shorter distances, and where operational hours are a more important concern than miles traveled, said Steve Homcha, Mack’s vice-president of class 8 programs.

Like many of the other OE cooled EGR engines, C-EGR functions when a portion of gases leaving the engine are diverted from the exhaust through a cooling system, and then remixed with air entering the engine for combustion. An improved filtering medium was then added to the oil filtration system, along with a new oil pan that accommodates an additional eight quarts of oil.

I-EGR instead allows a percentage of exhaust gases to remain in the cylinders of the engine from one combustion cycle to another. This approach provides a consistent level of emissions benefits and performance in the varying and often harsh environments in which vocational trucks operate, according to the company.

The strategy, which aims at reducing emissions, centers on optimizing the flow of exhaust gases through the system, in order to make it possible to retain a precise amount of gases in the cylinders for further combustion. That was accomplished through a new camshaft, advancements to the valve system, and precision machining of the exhaust ports to maximize aerodynamic flow.

“Mack does not believe that one EPA ’02 solution is the answer for all trucking applications,” Homcha said. “Our vocational customers wanted a simplified approach, and one that is optimized for their operational environment, and that’s what we are going to give them.”

Mack vehicles that will feature I-EGR engines as of October 1, 2002, include the new Mack Granite Series, as well as Mack RD6, MR, LE, DM and RB models. Seven engines will be available with varying horsepower ratings, including three Maxidyne models (a 300-horsepower, and new 335 and 370 horsepower versions) and four Econodyne (350, 400, 427, and 460E horsepower) models.

Ramp-up production begins in June.