Mack Trucks Inc has achieved a breakthrough in engine technology for the vocational truck market to meet requirements of Environmental Protection Agency (EPA) emissions regulations taking effect in October 2002.
The foundation for Mack's EPA '02 solution is a platform of diesel engines known as the ASET (Application-Specific Engine Technology) family. All ASET engines rely on exhaust gas recirculation technology as the basis for emission reductions.
The main component of the ASET emissions breakthrough is use of internal exhaust gas recirculation (I-EGR), a technology that 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 performance in the environments in which vocational trucks operate.
Mack said its I-EGR 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. These vehicles also travel in harsher environments than over-the-road highway vehicles. Consequently, Mack decided to develop the I-EGR engine to provide an optimized solution to vocational operating conditions.
For ASET engines ticketed for vocational applications, the Mack I-EGR approach to reducing emissions centers on optimizing flow of exhaust gases through the system, in order to retain a precise amount of gases in the cylinders for further combustion. That was accomplished through a new camshaft, improvements to the valve system, and precision machining of the exhaust ports to maximize aerodynamic flow.
Mack vehicles that will feature I-EGR engines as of Oct 1, 2002, include the new Granite Series, as well as Mack RD6, MR, LE, DM and RB models. Seven engines will be available with varying horsepower ratings. These include three Maxidyne models (a 300-horsepower, and new 335- and 370-hp versions) and four Econodyne (350-, 400-, 427-, and 460E-hp) models. Ramp-up production begins in June 2002.