Phillip Sharer

Integrating Data, Performing Quality Assurance, and Validating the Vehicle Model for the 2004 Prius Using PSAT

Argonne National Laboratory (ANL), working with the FreedomCAR Partnership, maintains the hybrid vehicle simulation software, Powertrain System Analysis Toolkit (PSAT). The importance of component models and the complexity involved in setting up optimized control laws require validation of the models and control strategies. Using its Advanced Powertrain Research Facilities (APRF), ANL thoroughly tested the 2004 Toyota Prius to validate the PSAT drivetrain. In this paper, we will first describe the methodology used to quality check test data. Then, we will explain the validation process leading to the simulated vehicle control strategy tuning, which is based on the analysis of the differences between test and simulation. Finally, we will demonstrate the validation of PSAT Prius component models and control strategy, using APRF vehicle test data.

Fuel Economy Sensitivity to Vehicle Mass for Advanced Vehicle Powertrains

In 2002, the U.S. Department of Energy (DOE) launched FreedomCAR, which is a partnership with automakers to advance high-technology research needed to produce practical, affordable advanced vehicles that have the potential to significantly improve fuel economy in the near-term. Advanced materials (including metals, polymers, composites, and intermetallic compounds) can play an important role in improving the efficiency of transportation vehicles. Weight reduction is one of the most practical ways of increasing vehicle fuel economy while reducing exhaust emissions. In this paper, we evaluate the impact of vehicle mass reduction for several vehicle platforms and advanced powertrain technologies, including Internal Combustion Engine (ICE) Hybrid Electric Vehicles (HEVs) and fuel cell HEVs, in comparison with conventional vehicles. We also explain the main factors influencing the fuel economy sensitivity.

Model Architecture, Methods, and Interfaces for Efficient Math-Based Design and Simulation of Automotive Control Systems

Many of today’s automotive control system simulation tools are suitable for simulation, but they provide rather limited support for model building and management. Setting up a simulation model requires more than writing down state equations and running them on a computer. The role of a model library is to manage the models of physical components of the system and allow users to share and easily reuse them. In this paper, we describe how modern software techniques can be used to support modeling and design activities; the objective is to provide better system models in less time by assembling these system models in a “plug-and-play” architecture. With the introduction of hybrid electric vehicles, the number of components that can populate a model has increased considerably, and more components translate into more possible drivetrain configurations. To address these needs, we explain how users can simulate a large number of drivetrain configurations. The proposed approach could be used to establish standards within the automotive modeling community.

Midsize and SUV Vehicle Simulation Results for Plug-In HEV Component Requirements

Because Plug-in Hybrid Electric Vehicles (PHEVs) substitute electrical power from the utility grid for fuel, they have the potential to reduce petroleum use significantly. However, adoption of PHEVs has been hindered by expensive, low-energy batteries. Recent improvements in Li-ion batteries and hybrid control have addressed battery-related issues and have brought PHEVs within reach. The FreedomCAR Office of Vehicle Technology has a program that studies the potential benefit of PHEVs. This program also attempts to clarify and refine the requirements for PHEV components. Because the battery appears to be the main technical barrier, both from a performance and cost perspective, the main efforts have been focused on that component. Working with FreedomCAR energy storage and vehicle experts, Argonne National Laboratory (Argonne) researchers have developed a process to define the requirements of energy storage systems for plug-in applications. This paper describes the impact of All Electric Range (AER), drive cycle, and control strategy on battery requirements for both the midsize and SUV classes of vehicles.

Well-to-Wheels Results of Energy Use, Greenhouse Gas Emissions, and Criteria Air Pollutant Emissions of Selected Vehicle/Fuel Systems

A fuel-cycle model—called the Greenhouse gases, Regulated Emissions, and Energy use in Transportation (GREET) model—has been developed at Argonne National Laboratory to evaluate well-to-wheels (WTW) energy and emission impacts of motor vehicle technologies fueled with various transportation fuels. The new GREET version has up-to-date information regarding energy use and emissions for fuel production activities and vehicle operations. In this study, a complete WTW evaluation targeting energy use, greenhouse gases (CO2, CH4, and N2O), and typical criteria air pollutants (VOC, NOX and PM10) includes the following fuel options – gasoline, diesel and hydrogen; and the following vehicle technologies – spark-ignition engines with or without hybrid configurations, compression-ignition engines with hybrid configurations, and hydrogen fuel cells with hybrid configurations. Based on the detailed up-to-date data, probability-based distribution functions for key input parameters regarding WTP activities and vehicle operations were built into GREET to address the uncertainties of energy use and emissions. The WTW analysis shows that advanced vehicle/fuel systems achieve reductions in energy use, GHG emissions and criteria pollutant emissions compared to baseline gasoline vehicles by 1) improved vehicle fuel economy, 2) declined tailpipe/evaporative vehicle emissions, and/or 3) differences in fuel production pathways.

Analyzing the Uncertainty in the Fuel Economy Prediction for the EPA MOVES Binning Methodology

Developed by the U.S. Environmental Protection Agency (EPA), the Multi-scale mOtor Vehicle Emission Simulator (MOVES) is used to estimate inventories and projections through 2050 at the county or national level for energy consumption, nitrous oxide (N2O), and methane (CH4) from highway vehicles. To simulate a large number of vehicles and fleets on numerous driving cycles, EPA developed a binning technique characterizing the energy rate for varying Vehicle Specific Power (VSP) under predefined vehicle speed ranges. The methodology is based upon the assumption that the vehicle behaves the same way for a predefined vehicle speed and power demand. When this has been validated for conventional vehicles, it has not been for advanced vehicle powertrains, including hybrid electric vehicles (HEVs) where the engine can be ON or OFF depending upon the battery State-of-Charge (SOC). The Powertrain System Analysis Toolkit (PSAT), a vehicle simulation software developed by Argonne National Laboratory, will be used to generate the MOVES bins as well as evaluate the errors. This paper will quantify and explain the fuel economy uncertainties introduced by the “average” vehicle in the representative source bins for several powertrain configurations, control strategies, and drive cycles defined in MOVES.

Impact of FreedomCAR Goals on Well-to-Wheel Analysis

Because of their high efficiency and low emissions, fuel-cell vehicles are undergoing extensive research and development. When considering the introduction of advanced vehicles, engineers must perform a well-to-wheel (WTW) evaluation to determine the potential impact of a technology on carbon dioxide and Greenhouse Gas (GHG) emissions and to establish a basis that can be used to compare other propulsion technology and fuel choices. Several modeling tools developed by Argonne National Laboratory (ANL) were used to evaluate the overall environmental and fuel-saving impacts associated with an advanced powertrain configuration. The Powertrain System Analysis Toolkit (PSAT) transient vehicle simulation software was used for pump-to-wheel (PTW) analysis, and GREET (Greenhouse gases, Regulated Emissions and Energy use in Transportation) was used for well-to-pump (WTP) analysis. This paper assesses the impact of FreedomCAR vehicle goals on a WTW energy basis. We will demonstrate that, on the basis of near-term (2010) advanced propulsion technologies, fuel cell hybrid vehicles achieve higher fuel economy than their Internal Combustion Engine (ICE) counterparts. However, when the North American natural gas hydrogen pathway is used to produce hydrogen (the most likely lowest-cost source of hydrogen in the near term), diesel hybrids perform the best. To gain the full benefits of hydrogen technology, a more efficient pathway to produce hydrogen, such as renewable energy, should be considered.