Serial Hybrid for a Tracked Vehicle

Background

The Department of Defense is pursuing next-generation main battle tank (MBT) powertrain upgrades. Defense suppliers were invited to propose configurations that meet or exceed the performance of existing legacy systems while introducing an additional 100 kW of peak electric power. The modernization effort aims to improve vehicle mobility, power density, and system integration while maintaining or reducing overall volume and mass.

Project Objective

To evaluate both series and parallel hybrid configurations against the legacy internal combustion engine (ICE) powertrain. The analysis focused on system-level volume trade-offs and SWAPC (size, weight, power, and cooling) considerations to determine which hybrid architecture offers the best packaging efficiency and allows space for additional onboard systems such as weapon or auxiliary power modules.

Approach

The study began with the characterization of the existing engine and transmission based on available legacy vehicle data. Using this baseline, ePOP engineers modeled hybrid alternatives incorporating modern electric motors and power electronics technologies from qualified suppliers. Both series and parallel non-plug-in hybrid architectures were simulated to assess efficiency and spatial impact.

Simulation and analysis proceeded through several key steps:

System Configuration: Series and parallel hybrid layouts were defined, including electric drive paths, transmission arrangements, and auxiliary power distribution.

Volume Assessment: Stepwise waterfall analyses were conducted to compare volume contributions from each major component in the legacy and hybrid configurations.

Component Optimization: The impact of battery technology and powertrain downsizing was studied to achieve volume reductions without compromising performance or mechanical efficiency.

Outcome

Results indicated that both hybrid configurations using LFP battery technology achieved modest powertrain volume reductions compared with the ICE baseline. For the series hybrid, gains in ICE efficiency and potential downsizing were partly offset by mechanical losses inherent to the architecture.

When applying NMC battery technology, the hybrid configuration demonstrated significant improvement—achieving over 500 L reduction in total powertrain volume relative to the legacy setup.

The findings confirmed that NMC-based hybridization provides a practical route to electrification for tracked vehicles, delivering enhanced power capability and space optimization while preserving reliability and mission readiness.

{{result}}