Validation of Hybrid and Electric Vehicle Models for ALPHA v3.0

The Environmental Protection Agency’s Advanced Light-Duty Powertrain and Hybrid Analysis (ALPHA) modeling tool was initially created to simulate the Greenhouse Gas emissions from light-duty vehicles. ALPHA is used to predict tailpipe CO2 emissions and energy consumption from advanced automotive technologies. ALPHA is a physics-based, forward-looking vehicle computer simulation tool capable of analyzing various vehicle types with different powertrain technologies while replicating realistic vehicle behavior. ALPHA version 3.0 is the current version of the MATLAB/Simulink based software. Key changes made for ALPHA v3.0 include the addition of new light- and medium-duty vehicle models to support simulation of electrified vehicle architectures (hybrid, plug-in hybrid, and battery electric vehicles) aligning with the automotive industry transition towards electrified fleets. Each electrified vehicle model was tuned to replicate operational behavior of components (such as engine, transmission, electric motor, and propulsion battery, if available) as observed in actual vehicle test data over EPA city, highway and US06 regulatory drive cycles. This paper focuses on the new electrified vehicle architectures and models, the input data used to represent these new technologies, and the comparisons of ALPHA’s simulation results to the corresponding vehicle chassis tests and EPA certification data. As a final comparison, the new models are used to simulate variant vehicles that are similar, but not identical, to the base vehicle used to validate each model. The validation of these new models enables EPA to use ALPHA v3.0 to estimate fleet-wide CO2 emissions and energy consumption for different types of new and emerging light- and medium-duty vehicles.