This project investigates design optimization of plug-in hybrid electric vehicle (PHEV) and extended range electric vehicle (EREV) powertrain architectures in terms of performance and efficiency. The motivation behind this initial effort is to develop a comparative method for assessing design choices for a given vehicle class that can be used to test those design choices through sensitivity analysis in later investigations.

Objective

This report describes a method for evaluating vehicle design decisions using computer simulations facilitated by Argonne National Laboratory’s (ANL) Powertrain Systems Analysis Toolkit (PSAT). The report’s objective is to describe an initial formulation of the evaluative method.

Approach

The project team evaluated conventional, power-split, and series vehicle architectures and proposed to test them in a future investigation through sensitivity analysis. The team identified several key areas for sensitivity analysis. These areas include drive trace, battery degradation, component sizing, and control strategy sensitivities.

The team focused on two vehicle classes and three different vehicle architectures. The vehicle classes investigated include a small sports utility vehicle and a midsize sedan.

The team will investigate the performance of each vehicle architecture and vehicle class. These vehicles will be subjected to standard EPA driving cycles: the EPA Urban Dynamometer Driving Schedule (UDDS) and the Highway Fuel Economy Test (HWFET) schedule. Each cycle will be repeated multiple times, and the vehicle energy economy will be tabulated for each cycle lap. The per-lap energy economy will then be plotted against total distance traveled. This plot will allow for a straightforward evaluation of the vehicle’s efficiency over a broad range of operating conditions.

PSAT v6.1 was selected as the software tool for this investigation.

Results

The report describes the vehicle specifications used for developing an initial methodology to assess design choices for small sports utility vehicles (SUVs) (conventional, power-split HEV, power-split PHEV) and midsize vehicles (conventional, series PHEV). Software and drive-cycle selections for the evaluative analysis are discussed as are initial test results.

Application, Value and Use

Once sufficient vehicle models have been developed, the models can be subjected to sensitivity analyses. Included in the sensitivity analyses are drive cycle, battery degradation, component selection, and control strategy sensitivities.

EPRI Perspective

The model design of the vehicles investigated was performed with limited input from industrial partners. Feedback from this report will be used to help improve the study’s design criteria and component assumptions. Testing partners also will provide data from prototype vehicles to validate the vehicle models.