The FORTÉ CFD Package is the only CFD simulation package for combustion engines that incorporates proven CHEMKIN-PRO solver technology – the gold standard for modeling and simulating gas-phase and surface chemistry. Designers can now break through the historical chemistry model size limitation in CFD to investigate key design issues, such as soot formation and engine knock.

Today’s engine designers face challenges in the design of low-emissions, high-performance vehicles that can run on a wide variety of fuels. New engine design strategies for emissions control and performance improvement make fuel and pollutant chemistry critical factors that can determine overall engine performance. Combustion CFD simulation has the potential to help create better engine designs at reduced cost and in less time. However, that simulation must be able to account for real fuel effects using the appropriate amount of kinetics detail in order to be a trusted part of the engine design flow.

Conventional CFD simulation packages cannot handle the complexity of real fuel models, which handicaps their ability to predict quantitative outcomes, or even accurate trends. Significant time is spent in calibrating conventional CFD models to account for the lack of accuracy in the fuel chemistry model. What proved to be good enough for the design of yesterday's engines is insufficient for today's new engine designs. FORTÉ’s ability to calculate combustion with accurate chemistry reduces reliance on costly calibration, enabling superior Time-to-Solution metrics that fit in commercial-development timeframes.


Accuracy or Time-to-Solution?

Today’s engine designers are under pressure to speed up design time and lower the cost of developing more efficient engines that burn cleaner. Combustion CFD offers the promise of greatly reducing experimental testing costs and speeding development while improving design quality, but only if it helps accelerate the development timeline and can be trusted.

FORTÉ dramatically reduces the Time-to-Solution for combustion CFD through advances in every phase of the design flow.

  • Automatic mesh generation allows a fast transition from import of CAD files to solving your case
  • Industry’s most advanced spray models do not require dense mesh patterns or extensive calibration
  • Embedded  CHEMKIN-PRO solvers handle real fuel chemistry in the time it takes most others to converge with their inaccurate, simple chemistry models
  • Quick set-up of automated parameter studies to enable virtual design-of- experiments  
  • Visualization of results and comparison to experiments without third-party tools
FORTÉ delivers dramatic reductions in Time-to-Solution over conventional CFD approaches


Identifying the correct trends through simulation is critical to making good design decisions. Today’s engine designs are increasingly dependent on the ability to exploit fuel behavior and control combustion to improve performance and emissions. Accurately modeling real fuel behavior requires more chemistry than traditional CFD approaches can handle while delivering acceptable Time-to-Solution.

FORTÉ’s powerful chemistry solvers deliver the speed required to use accurate fuel chemistry without sacrificing Time-to-Solution.


Dramatically reduced chemistry calculation times enable the use  of more accurate chemistry for predictive results  without the need for extensive calibration


Employing industry-leading CHEMKIN-PRO solver technology, FORTÉ ensures you get the right answer, right on time. Now you can use more accurate chemistry in an order-of-magnitude less time than it takes to find a solution with commonly used reduced mechanisms in traditional CFD.

Modeling Fuel Effects is Key to Predictive Simulation

FORTÉ improves Time-to-Solution without sacrificing accuracy. Its embedded CHEMKIN-PRO solver technology enables the use of more accurate fuel models for more predictive simulation results. Reaction Design’s Model Fuels Consortium (MFC) spent seven years developing and validating the detailed chemical mechanisms needed to simulate real fuel behavior.

Most chemistry models in use today are slow and lack sufficient detail for accurate and predictive results. While it is widely accepted that the use of more detailed chemical mechanisms is required for accurate prediction of important characteristics of the combustion process, such as ignition, flame propagation and emissions production, many designers don’t believe they have the option of incorporating these mechanisms into their simulations without significant increases in compute time and solution instability. As a result, designers cannot rely on their combustion CFD to predict values or even accurate trends in these critical combustion behaviors.

Accurate, fast chemistry simulation is required for:

  • Predictive ignition calculations
  • Predictive engine knock simulations
  • Predictive emissions calculations

Detailed chemistry mechanisms for fuel required to accurately predict emissions in engines

Predict Soot Emissions

Soot (also known as Particulate Matter or PM) production is a major consideration for today’s advanced engine designers. Engine operating conditions such as pressure, temperature, fuel‐air equivalence ratio, quantity of EGR and boost level can all affect the formation of soot. Simple, two-step soot models used in legacy CFD packages assume soot is formed from a single chemical precursor and oxidation is represented by a single step. These models often fail to accurately predict soot emissions, or even trends, without substantial calibration. Soot formation involves complex chemical interactions with multiple precursor elements combined with the physical interactions that take place in an engine. The work completed by the Model Fuels Consortium validated that several chemical reactions control oxidation and once a soot particle is formed, it can grow and combine with other soot particles to form agglomerate, which can then, in turn, also oxidize. Real fuels are a blend of many different hydrocarbon species and some of these species contribute more to soot formation than others. Accurate soot modeling in CFD requires the use of a multi-component fuel model that can predict all of the precursors to particle formation as well as the oxidation reactions that occur while also accounting for particle agglomeration. 

FORTÉ was created specifically to enable the simulation of IC engine behavior using accurate multi-component fuel models without the extreme computational runtime penalties encountered when using other CFD packages. FORTÉ also has a particle tracking model that can calculate soot particle number density and average particle size, in addition to total mass emissions. FORTÉ allows investigations of how soot emissions are affected by factors such as operating conditions, EGR, injection timing and fuel composition.

FORTÉ with accurate soot chemistry predicts soot emissions trends with increasing EGR


See where and when soot is formed with FORTÉ

Predict Knock Intensity

Knocking in engines is an undesired combustion phenomenon that limits how efficiently an engine can operate, produces noise and can result in severe engine damage. Knock results from auto ignition of the unburned gas in front of a spark-ignited flame front, disrupting normal flame propagation across the cylinder. For downsized and boosted SI engines, knock represents a constraint on performance and efficiency since it inhibits the uses of more advanced spark timings, higher compression ratios and/or higher boost pressures. As uncontrolled autoignition is the root cause of knock, accurate modeling of both autoignition and flame propagation in the cylinder is critical to successful prediction of knock.

IC engine CFD simulation approaches that require the use of severely reduced fuel chemistry models are unable to accurately emulate real autoignition behavior. It is possible to capture autoignition chemistry for a wide range of conditions yet it requires a larger fuel model containing hundreds of species. FORTÉ makes use of proven CHEMKIN-PRO solver technology allowing simulations with 100s of species and 1000s of reactions while maintaining practical Time-to-Solution. To predict knocking, autoignition events in the simulation are monitored by virtual sensors defined in the FORTÉ CFD user interface, and then analyzed with signal processing techniques that mimic experimental setups during solution Visualization. The results are used to calculate Knock Intensity.

Engineers can use FORTÉ to investigate the impacts of design features such as boost, compression ratio, spark timing and fuel variations on knocking tendency before an engine is built. This advancement in knock simulation enables an optimization of engine performance, fuel economy and emissions reduction to suit today’s market, regulatory and environmental objectives.

Knock intensity CFD simulations with FORTÉ

Optimized Spray Model for All Engine Types

The choice of spray models can have a significant impact on both Time-to-Solution and the accuracy of results. Many spray models are highly mesh dependent, requiring that valuable time be spent refining the mesh, or adding mesh complexity, to find an acceptable combination of model parameters and grid mesh. Even when a spray model is calibrated to a particular grid, it is unclear how accurate the model will be when attempting to predict the behavior of a different engine design.

FORTÉ’s multi-component spray model maintains consistency between the physical properties of the engine and the chemical model of the fuel to more accurately capture droplet evaporation and ignition. This allows for a more accurate spray model without the need to drastically increase mesh refinement. Less calibration means better portability to other designs. 

Spray-droplet visualization at the start of injection  for a Diesel sector-mesh simulation

From CAD to Accurate CFD Model Automatically

Conventional CFD gridding techniques require that valuable time be spent refining the mesh, or adding mesh complexity, to find an acceptable combination of spray model parameters and grid mesh.

From an accuracy point of view, however, the ideal mesh is one that is Cartesian, with perfectly orthogonal faces, and one in which the boundary conditions can be applied exactly on the physical surfaces of the real geometry. Both unstructured-mesh and cut-cell approaches require a very large degree of mesh refinement at the boundaries to approximate the real boundary surfaces for useful geometries (such as a cylinder). This translates to longer compute times, especially when chemistry calculations are needed in each cell.

Automatically generating a mesh at runtime enables grid refinement and geometric parameter studies and improves Time-to-Solution by removing the meshing "bottleneck." With virtually no intervention from the user, FORTÉ reads CAD files directly and imports the detailed geometry information it needs to automatically generate a high-quality, well-structured, Cartesian mesh. The advanced automatic mesh-generation technology in FORTÉ includes full valve motion and 3-D mesh capability.

FORTÉ Visualizer animation of automeshed engine model geometry

See and Analyze Results Without Exporting

FORTÉ’s built-in Visualizer generates quick graphical representations of simulation results. Visualizations are intuitive and interactive, with support for cut-planes, line probes, phi-T map generation and external data import, eliminating the need for 3rd-party post-processing tools.


FORTÉ's built-in Visualizer eliminates the need to export results


Drive the tools; don’t let the tools drive you. You don’t have to be an expert user of FORTÉ to get the results you need quickly and accurately.

Product Literature


Introduction to FORTÉ
Demonstration of how design engineers can use the new FORTÉ CFD Package to get quick and accurate predictions of engine behavior and emissions across the broadest range of fuels with scientifically proven fuel models.
Soot Modeling in IC Engines with FORTÉ
Demonstrates how to use FORTÉ to simulate diesel combustion with predictions of emissions such as NOx, CO and Unburned Hydrocarbons (UHC).
Emissions Modeling with FORTÉ
Demonstrates how engine developers can use the FORTÉ CFD Package to predict soot particle sizes and track their progress from formation through agglomeration and reduction in an engine.

Modeling Engine Knock with FORTÉ
Demonstrates how to use FORTÉ to investigate knocking by creating a set of automated parameter study simulations that vary spark timing, engine boost, and fuel additives and compositions.


ANSYS Forte - Follow the Chemistry

Accurate chemistry is crucial for predictive internal combustion CFD. See where real chemistry knowledge can take you with ANSYS Forte.

FORTÉ Meshing Demo

This demonstration reveals how ANSYS Workbench with DesignModeler and Meshing can be used to generate an ANSYS Fluent mesh file for use in FORTÉ .

FORTÉ Knock Demo

Learn how superior chemistry and fuel surrogates allow users to predict knocking in an SI engine using FORTÉ combustion simulation software.

Introduction to FORTÉ 

See an overview of the major components of the FORTÉ CFD Package. It also provides an overview of the FORTÉ software's User Interface, which is used to set up CFD simulations. 

Fixing Reversed Normals in FORTÉ 

Learn how to fix inverted, or reversed, normals for a surface in FORTÉ.

Full Cycle Refinement in FORTÉ 

Gain an understanding of various refinement strategies employed within FORTÉ. 

Sector Mesh in FORTÉ 

Learn how to build a sector mesh in FORTÉ.