Romax Energy

Part of the Romax toolset, Romax Energy offers robust methods for transmission efficiency simulation and optimisation. Leveraging advanced tribological models, Romax Energy calculates power loss, fuel consumption and emissions, and enables understanding of the impact of bearing and gear designs, as well as oil specification, on system efficiency.

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Romax: Integrated powertrain simulation

Romax Energy is part of the Romax portfolio, an integrated toolset for ePowertrain engineering from concept exploration to virtual product sign-off.

Looking out of left hand window of car driving along road, sun setting

The challenge

Modern transmissions must balance multiple conflicting criteria. With the introduction of strict legislation aiming to reduce global emissions and environmental impact, increasing efficiency is usually a high priority for transmission designers. The right simulation tools can help engineers to design more efficient transmissions, to reduce fuel consumption (ICE) and/or extend range (EV).

ROMAX Energy simulation software shown on a desktop monitor

The solution

Romax Energy predicts transmission power losses for a vast range of applications (from automotive to aerospace and beyond). Its simulation methods have been used and validated in numerous projects and are proven to improve driveline efficiency. Simulations are accurate, but also quick to run, so that engineers can meet efficiency targets while satisfying the need for shorter development cycles.


Romax Energy enables transmission design engineers to predict efficiency of electro-mechanical systems, and ultimately to design more efficient products while balancing other conflicting performance criteria. 

Rapid design

Build parametric models of any full drive system rapidly (in minutes), with an easy-to-use drag-and-drop 2D modelling interface and a live reflection of the model in 3D visualisation. Models (starting with basic shaft, gear, bearing arrangements) can be created from scratch, imported from other Romax products, from CAD geometry, or via a number of other interfaces such as REXS.

Romax offers multi-fidelity component models across the full system:

  • Model helical, spur and planetary gears as loading (ratio only), concept (teeth/module defined), detailed (macro/micro geometry)
  • Model bearings initially as linear stiffnesses, then select from comprehensive bearing catalogs or design a custom bearing
  • Import/create and condense FE components (or import from FEA), and model flexible FE bearings and gear blanks

Models can then be converted to MBD, CAD, CFD and other formats to save time on data re-entry.

Combining state-of-the-art gear and bearing contact models with the latest standards and stress-based life calculations, Romax offers fast, proven prediction of component performance and full-system structural deformations. Romax’s holistic approach to system simulation considers the cumulative effect of the complex interactions between all components:

  • Shaft deflections
  • Gear misalignments and shifting contacts
  • Housing flexibility
  • Non-linear, load-dependent bearing stiffness
  • Component stresses and loads

Analyses are appropriate to model fidelity, ranging from fast approximations when evaluating design concepts to more detailed analyses during virtual testing and design for manufacture. Thanks to its hybrid approach of FE, analytical and empirical methods, Romax is able to provide this analysis very quickly. The most computationally-efficient and accurate method is used for each part, and combined into a fully-coupled system simulation that provides the optimal blend of speed and accuracy, specifically designed for powertrain simulation.

Romax full system gearbox simulation model, with annotations to show various ways of modelling components with varying fidelity

Comprehensive efficiency models calculate transmission efficiency and emissions so you can design highly efficient transmissions. Romax Energy allows you to:

  • Create system efficiency maps and calculate energy losses, equivalent fuel consumption and CO2 emissions, or EV energy consumption
  • Conduct advanced efficiency analysis using standard methods and industry-leading proprietary loss models that account for detailed bearing, gear and lubricant parameters
  • Analyse losses at a component level to find the most lossy components and redesign the system to optimise for efficiency
  • Perform quick parametric studies to investigate the impact of different gear, bearing and lubricant designs on system efficiency
  • Select from a built-in lubricant database, customise lubricants, or create your own and specify individual component lubricant properties

Romax Energy

A quick and easy-to-use interface from Romax Energy to Particleworks helps you conduct CFD simulations early in your design process. Optimise for sustainability, promote CAE-led design and enable informed engineering decisions to be made earlier, shortening development timescales and reducing the need for testing.

  • Export a fully valid model from Romax that will run on Particleworks with little CFD expertise required, using the default parameters set through best engineering practises
  • Study variations of different parameters such as fill height, temperature and speed and the resulting impact on fluid distribution and churning loss
  • Understand system lubrication performance under extreme conditions (hill starts, cornering, etc.)
  • Obtain more accurate, high-fidelity churning loss for critical operating conditions to understand and improve system efficiency
  • Use results to redesign the system to ensure proper lubrication while minimising churning loss

A quick and easy-to-use interface from Romax Energy to Particleworks helps you conduct CFD simulations early in your design process

Integrated ePowertrain design 

Romax Energy is part of the Romax portfolio, which means you can use the same model in common file formats for multi-attribute, multi-fidelity, full system design, simulation and optimisation. Our product range starts with Romax Concept, the perfect platform for early-stage investigation and design space exploration, and extends through Romax Enduro, Romax Spectrum and Romax Energy, for analysis and optimisation of durability, NVH and efficiency within a single model. Romax Spin adds world-leading bearing design and analysis capabilities, while Romax Evolve provides the perfect tool for electric machine designers looking to investigate the structural and NVH performance of their motor.

Beyond Romax, we have interfaces with dozens of other tools in the Hexagon portfolio and beyond. So, whether you are wanting to take your Romax powertrain into a full vehicle MBD model in Adams, or import electromagnetic loss data to be considered in the efficiency prediction of your electric machine, Romax will sit at the heart of your workflow.

“Efficiency maps of transmissions can be very hard to calculate, so we needed Romax to provide this information.”
Technische Universität Darmstadt
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