Class-8 Heavy Truck Duty Cycle Project Final Report - Center for ...

Fig. 4. Modified HHDDT Cruise Module for Highway Line Haul Operations
Another version of a highway line haul cycle that EPA indicates is suitable for use only on a chassis
dynamometer, was created by Southwest Research Institute (SRI), using input from a group of
stakeholders, including EPA, Northeastern States for Coordinated Air Use Management
(NESCAUM), several truck and engine manufacturers, state organizations, and others, for a
NESCAUM heavy truck fuel efficiency modeling and simulation project. It is similar to the option in
Fig. 4, although the top and average speeds are increased, there are grade impacts, there is less
transient operation, and idling is handled in a separate cycle. A graphic of this version of the
highway line haul drive cycle is provided in Fig. 5.
Fig. 5. Southwest Research Institute Modified HHDDT Cruise Module for Highway Line Haul
Operations
EPA indicated that each of these cycles may be considered, with the potential to combine features of
each into a final Highway Line Haul cycle. Furthermore, EPA indicated that data and input on
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