PHEV Modeling:
Impact of Powertrain Configuration on Fuel Efficiency

To evaluate the fuel efficiency potential of plug-in hybrid electric vehicles, it is necessary to compare the advantages and drawbacks of several powertrain configurations, ranging from power split to parallel and series.

PSAT offers the unique ability to simulate and compare hundreds of powertrain configurations. The goal of the effort is to define the most promising configurations depending on the particular usage.

Component sizes, fuel efficiency and cost will be used to make appropriate decisions. The configurations currently being considered include, but are not limited to:

• Pre-transmission parallel HEV
• Post-transmission parallel HEV
• Power split HEV (including THS II and GM 2 Mode)
• Series

The figure below shows an example comparison of three powertrain configurations (parallel, series and power split).

For each configuration, several control strategies are being assessed using both global optimization and heuristic optimization.

May 2008