In 2003, EPRI and DaimlerChrysler initiated a three-part collaborative effort to 1) develop and demonstrate a plug-in hybrid electric vehicle (PHEV) based on the Sprinter vehicle platform, 2) deliver prototype Sprinter PHEVs to fleets within the United States, and 3) explore these benefits in the context of commercial fleet use. As part of this effort, EPRI assumed the responsibility of managing data acquisition and analysis. This report focuses on evaluation of the PHEV Sprinter tested by the South Coast Air Quality Management District (SCAQMD).

Objective

The PHEV Sprinter data analysis objectives center around determining vehicle, component, and control system performance. The report, itself, focuses on performance results for the SCAQMD Sprinter as well as the implications of those results for Sprinter platform performance and future testing projects.

Approach

The project team developed data acquisition and analysis goals with DaimlerChrysler and the initial group of project participants. In response, a MATLAB®-based analysis toolkit has been developed to efficiently manage the data collected, translate the binary data into useful engineering data, produce graphical reports, and statistically summarize the engineering data.

Results

This report describes the PHEV Sprinter data analysis and specifically addresses the following: analysis objectives, data available through the existing acquisition system, data analysis results, and recommendations for enhancing the data analysis capabilities to better satisfy the analysis objectives. Areas evaluated include vehicle mode, vehicle performance, drive trace, component performance, and control strategy.

The vehicle mode operation evaluation contains time and distance as well as battery-energy-in-based and battery-energy-out-based mode distributions. These distributions are used to understand the conditions under which the report's data was acquired.

The vehicle performance evaluation involves analysis of vehicle drivability and overall system efficiency. Vehicle drivability is characterized by assessing driver response to vehicle operation. Vehicle efficiency is characterized by assessing electric and liquid fuel consumption in the vehicle's operation.

The drive trace analysis provides a detailed evaluation of the vehicle driving characteristics. The vehicle acceleration, speed, stopping frequency, and distance are used to characterize the driving pattern. While the full drive trace analysis method was not employed at the time of this report, the most critical analysis—a two-dimensional time-based histogram for vehicle acceleration versus speed—was completed. Results are presented for electric vehicle drive and hybrid vehicle drive operating modes.

The vehicle component performance evaluation focuses on each component's operation. The components listed for evaluation include vehicle accessories, transmission, torque converter, electric motor, battery pack, engine clutch, and engine.

The control strategy evaluation is concerned with how the vehicle components are used to satisfy driving demand and how the strategy impacts vehicle performance and efficiency. Control strategy decisions include vehicle operating mode selection, propulsion power commands from the motor and engine, transmission ratio, and torque converter slip speed.

Application, Value and Use

The goal behind the PHEV Sprinter data analysis is to evaluate PHEVs in the real world and to make recommendations for improving vehicle efficiency and performance. This report will be of value to PHEV fleet testing partners and participants in future data collection and analysis efforts.

EPRI Perspective

The work summarized in this report revisits the objectives set forth by the original Sprinter PHEV fleet testing scope-of-work. This report expands upon EPRI's Plug-in Hybrid Electric Vehicle (PHEV) Prototype Testing and Evaluation—Data Collection and Analysis report (1015875, December 2008), which documents the PHEV data analysis capabilities developed at EPRI. Other related EPRI reports include Plug-in Hybrid Electric Sprinter Van—Final System Design Specification: Phase 1 Prototype Vehicles (1008761, March 2005) and Plug-in Hybrid Electric Vehicle Data Collection and Analysis Plan (1012462, February 2007).