HTEBdyn Heavy Truck Energy Balance Dynamic Model
The Heavy Truck Energy Balance Dynamic (HTEBdyn) model estimates the impact of technology improvements and innovations on heavy truck fuel consumption for a variety of duty cycles. The model was specifically developed by TA Engineering, Inc., to support analysis of the benefits of U.S. Department of Energy Vehicle Technologies Office programs in terms of fleet level reductions in energy and petroleum consumption and associated emissions and it is designed to interface with the analytical tools used for that assessment.
HTEBdyn is flexible and may be easily modified to suit the users’ needs. The model is capable of analyzing waste heat recovery systems and hybrid drivetrains. HTEBdyn is not a full vehicle simulation model, but rather, a tool that provides quick analysis and rough estimation of fuel consumption benefits based on user input engine, drivetrain, and vehicle system characteristics. Power flows are itemized to allow allocation of fuel consumption benefits by vehicle functional area.
The HTEBdyn model estimates driving loads and losses at discrete time steps over a defined drive cycle. The power demands are then averaged over the cycle and idle power demand is added, resulting in an estimate of the vehicle's duty cycle fuel economy. The model is compatible for use with Class 3-6 and Class 7 and 8 trucks. Vehicle characteristics and use parameters in the model include the following:
- Truck class;
- Truck weight;
- Vehicle idle time;
- Aerodynamic drag coefficient and frontal area;
- Tire rolling resistance coefficient;
- Engine displacement;
- Engine gross indicated efficiency;
- Engine friction losses;
- Engine-driven accessory losses;
- Vehicle electrical demands/losses;
- Transmission gear ratios and efficiencies;
- Driveline efficiency;
- Waste heat recovery system efficiency;
- Hybrid electrical system sizing; and
- Drive cycle scheduled speed and grade.