CAE - Dinex Emission Technology

Computer Aided Engineering

The CAE (Computer Aided Engineering) process at Dinex is divided into three main steps;
1) The first step is a 1D system simulation of emission performance.
2) The second is a system design and the third is a system performance evaluation.

The system layout is evaluated using a 1D tool. The system is designed using a CAD (computer aided design) tool, and the system performance is evaluated using FEA (finite element analysis) NVH (noise, vibration and harshness) and CFD (computational fluid dynamics) tools.
The FEA tools predict the dynamics and fatigue of the system in order to increase the strength and lifetime of the exhaust system.
The NVH tools predict the acoustic performance of the system in order to increase the attenuation of the system.
The CFD tools predict the fluid and chemical performance of the system in order to increase the uniformity indices and efficiency while reducing backpressure.

Computer Aided Design – CAD:

The design is created using the 3D CAD tool SolidWorks which enables the designers to make 3D models of parts and complete system assemblies. The input to the design from customer’s side are:

  • Requirements;
    • Performance, durability, materials, serviceability etc.
  • Vehicle information;
    • Layout, space envelope, parts attached, road load data, engine & emission data
  • Dosing & substrates;
    • Injector details, requirement to substrates sizes/coating

The output from the design phase are:

  • A-sample flexible concept emission testing
  • B-sample on prototype tooling for DV testin
  • C- & D-samples on serial tooling for PV tests

 Simulation mesh of an off-road exaust after treatment system

Simulation mesh of an off-road exhaust

after treatment system

Finite Element Analysis - FEA:
The structural strength, thermal and vibration performance, along with fatigue and life time prediction of the exhaust after treatment system is evaluated using Ansys Mechanical. Ansys is a 3D FEM based tool, where inputs are material fatigue data and customer vibration load data.

Main outputs from the FEA simulation are:

  • Stress level & displacement amplitudes
  • Natural frequencies and mode shapes
  • Life time and fatigue prediction

The FEA simulations are validated with the vibration test & surface temperature tests.


Deformation of forced response

Noise, Vibration & Harshness - NVH:

The acoustic performance of the exhaust after treatment is evaluated using Comsol Multiphysics. Comsol is a 3D FEM tool with linear pressure acoustic capabilities.

Main outputs are:

  • Transfer matrix
  • Transmission loss

The NVH simulations are validated with the flow acoustic test rig.

Sound pressure level distribution

Computational Fluid Dynamics - CFD:

The fluid dynamic performance of the complete exhaust system is evaluated using AVL Fire which has special capabilities within engine and aftertreatment systems.

Main output from the 3D CFD simulations are:

  • Flow uniformity index & Flow distribution
  • Backpressure
  • Heat loss and surface temperature
  • Ammonia (NH3) uniformity index

The CFD simulations are validated with engine dyno tests.


Urea droplet & NH3 distribution

Exhaust After treatment simulation – 1D CFD:

The fluid dynamic & emission performance of the complete exhaust system is evaluated using AVL Boost which has special capabilities within engine and after treatment systems. AVL Boost is a 1D CFD & reaction kinetics tool.

Main output from the simulations are:

  • Heat-up time
  • Tail pipe NOx emissions
  • DOC & SCR Light off
    • DPF soot loading & regeneration

The 1D simulations are validated with SGB & engine dyno tests.



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