Thomas new first Saf-T-Liner HDX school bus equipped with Detroit DD8 engine. The first Saf-T-Liner HDX school bus equipped with the new Detroit™ DD8™ engine at the STN Expo in Reno, Nevada on July 17. A 7.7L in-line 6-cylinder medium-duty engine with specific development for the Thomas Built Buses Saf-T-Liner HDX, the DD8 boasts a horsepower range of 260-350HP and a torque range of 660-860 lb.-ft.
The DD8 engine, which is the latest in engine technology, will deliver proven power, performance and best-in-class fuel economy and reliability, in addition to easier serviceability and a low total cost of ownership. It features top-load oil and fuel filters and the longest service intervals in its class, with up to 45,000-mile change intervals. Plus, the oil and fuel filters are positioned above the frame rails for easier, faster and cleaner filter changes.
Manufactured from the ground up, the engine features a simple fixed-geometry turbo design that provides performance and reliability along with an integrated engine brake option for superior braking horsepower to extend service brake life. Plus, smart, fuel-efficient design makes the most of every gallon as the advanced common rail fuel system optimizes each injection event to minimize fuel consumption. The result is at least a three percent increase in fuel efficiency compared to other diesel engines in this category.
The DD8, which was specifically designed to produce low emissions, meets 2017 greenhouse gas (GHG17) standards and will continue to meet emissions requirements through 2020. In addition, the DD8 utilizes innovative technology such as variable cam exhaust phasing, which allows additional heat to the exhaust stream. This innovative technology enables efficient operation of the aftertreatment system in school buses in low speed stop-and-go operations.