At the Mid-America Trucking Show, Mack Trucks announced plans to offer two exhaust-gas recirculation (EGR) engines to meet this fall's emissions reduction deadline — one for highway fleets and the other for vocational applications. Both are part of the company's ASET engine group, for Application Specific Engine Technology.

Mack said the engines for on-highway fleets will use cooled EGR (C-EGR) technology, while vocational fleet engines will be equipped with internal EGR (I-EGR) technology. C-EGR recirculates exhaust back into the engine's combustion chamber to burn off emissions, while I-EGR keeps the exhaust in the engine's cylinders from one combustion cycle to the next to reduce emissions.

Mack explained that I-EGR technology wouldn't be used for its on-highway engines because the fuel penalty would be too severe. When used in vocational operations, however, I-EGR does not result in the same degree of fuel penalty. The OEM said that C-EGR engines would have a fuel penalty of about 3% and cost an additional $3,000 per vehicle.

Also new from Mack is the Vision day cab tractor, which is built around a 113-in.-BBC chassis to save weight and provide more maneuverability. The Vision day cab is available in Class 8 tractor and straight truck configurations, in either single rear or twin rear axle combinations; GVW ratings range from 35,000 to 60,000 lb. The Vision day cab will go into limited production in June, with full production slated for October.

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