National Renewable Energy Laboratory

Vehicle Systems Analysis

Vehicle and Component Simulation

NREL's vehicle systems analysts use a tiered approach that encompasses our suite of analysis tools. By choosing the right tool for the job, we deliver exceptional value to our clients. Our modeling levels include:

• High-level modeling
• Exploratory modeling
• Detailed modeling
• Robust design

High-Level Modeling

We use a high-level model for quick vehicle design studies and cycle-related requirements analyses. This model uses basic vehicle parameters and duty cycle definition to calculate:

• Duty cycle statistics (average speeds, histograms, etc.)
• Time-step averaged power and energy requirements (road loads)
• First-pass fuel economy estimates.

The model's agility lends itself to preliminary design where assumptions and requirements can change quickly. Types of outputs include:

• Trade studies
• Traction power versus time
• Requirements analysis (fuel economy).

For high-level modeling, we use the following software tools:

• GREET
• VISION.

Exploratory Modeling

We use an exploratory model for investigating:

• Energy management strategies
• Component type and sizing interactions
• The performance and energy implications of several powertrain architecture designs.

Exploratory model characteristics include:

• A blend of speed with sufficient detail
• Easy configuration with the ability to work optimization codes
• Insufficient detail for HI.

We use the following software tools for exploratory modeling:

• ADVISOR
• AVL Cruise
• Technical Targets Tool.

Our applications of exploratory modeling include plug-in hybrids and heavy-duty hybrids.

Detailed Modeling

We use detailed modeling in anticipation of and during an actual vehicle build. With this model, we can:

• Implement actual controllers
• Offer support for hardware-in-the-loop
• Provide more in-depth analysis of events and transients.

We use the following software tools for detailed modeling:

• BOOST
• FIRE
• PSAT (Powertrain System Analysis Toolkit)
• SimDriveline.

Robust Design

Robust design integrates the latest computer-aided engineering (CAE) tools with advanced design techniques to solve key technical barriers and to accelerate the development process. It's based on optimization from the system's view.

We can apply robust design to:

• Topology optimization for conceptual design
• Parametric behavioral modeling with computer-aided design (CAD)
• Finite element modeling (implicit, explicit)
• Multi-physics applications (structural/thermal, fluid/thermal, electromagnetics, etc.)
• Optimization integrated with CAD and finite element analysis (FEA)
• Design for 6-sigma (DFSS) using CAE
• Probabilistic design methods (engineering quality into designs)
• Design of experiments techniques
• Vehicle systems analysis tools.

Learn More

See our vehicle and component simulation publications for more information.