Benchmarking and Modeling of a Conventional Mid-Size Car Using ALPHA 2015-01-1140

The Advanced Light-Duty Powertrain and Hybrid Analysis (ALPHA) tool was created by EPA to evaluate the Greenhouse Gas (GHG) emissions of Light-Duty (LD) vehicles [1]. ALPHA is a physics-based, forward-looking, full vehicle computer simulation capable of analyzing various vehicle types combined with different powertrain technologies. The software tool is a MATLAB/Simulink based desktop application. The ALPHA model has been updated from the previous version to include more realistic vehicle behavior and now includes internal auditing of all energy flows in the model. As a result of the model refinements and in preparation for the mid-term evaluation of the 2017-2025 LD GHG rule, we are revalidating the model with newly acquired vehicle data.

This paper presents the benchmarking, modeling and continued testing of a 2013 Chevy Malibu 1LS. During the initial benchmarking phase, the engine and transmission were removed from the vehicle and tested and evaluated on separate test stands. Data from the benchmarking was provided to the ALPHA model to perform full vehicle simulations over several drive cycles and vehicle road loads. Subsequently, the vehicle was reassembled and underwent further evaluation and testing to refine the inputs to the model. This paper presents the collected data, the methods for developing the model inputs from the data, the results of running the ALPHA model, and the lessons learned during the modeling and assessment activity.