ICE / BEV / Hybrid Scenarios for 8×8 Vehicle

Background

8×8 vehicles represent one of the largest fleets of combat vehicles in service today. A leading 8×8 supplier initiated an investigation into an eAxle variant aimed at improving overall operational flexibility. The goal was to enhance vehicle capabilities such as silent mobility, energy efficiency, and maneuverability while maintaining payload and performance standards. Because the electrification of heavy tactical platforms is still an emerging domain, Department of Defense requirements remain loosely defined.

Project Objective

To identify viable hybrid powertrain options that extend vehicle range whist maintaining vehicle load space. The project sought hybrid configurations capable of matching the range and performance of the legacy diesel Defender whilst maintaining compatibility with existing power requirements.

Approach

The study began with the detailed characterization of the legacy mechanical transmission and drive shafts. Using these baselines, ePOP engineers modeled potential electrified configurations, focusing exclusively on series hybrid topologies to maximize compatibility with eAxle technology. Multiple simulation steps were conducted:

1. Power Profiling: Power demand profiles for five representative 8×8 functions were derived from existing vehicle data.
2. System Modeling: Electrified powertrain variants were modeled, integrating eAxles for propulsion and an ePump for hydraulic systems. HVAC loads were supported by an electric compressor.
3. Optimization: Volume and mass sensitivity analyses were performed across different battery chemistries and configurations to identify the most efficient hybrid and BEV options.

Outcome

Results showed that hybrid architectures provided the most practical balance of performance and packaging efficiency.

• A hybrid powertrain using LFP batteries achieved comparable volume to the legacy ICE while maintaining manageable mass.
• A hybrid system using NMC batteries demonstrated clear advantages in both mass and volume, achieving a 44% reduction in powertrain volume with a 179 kWh configuration.
• In contrast, a full BEV solution would require two to three times the powertrain volume of the legacy system, depending on the selected battery chemistry.

Overall, the analysis highlighted that hybridization—particularly with NMC-based systems—offers a near-term, low-risk pathway to electrification for heavy defense platforms without compromising space or mission performance.

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