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How to Minimize Particle Emissions Caused by Nozzle Tip Wetting

News from AVL’s Virtual ICE Development

There can be no doubt that emission legislation has a major impact on engine development strategies. Engineers investigate every detail of the emission formation process in order to find potential for improvement. Recently, the focus of engine developers has moved towards nozzle tip wetting as a source for GDI engine particle emissions.

To minimize nozzle tip wetting and soot layer formation, and to avoid clogging, AVL offers its 3D CFD Software FIRE™. Our simulation solution allows you to determine the impact of design parameters, operating conditions and fuel properties on tip wetting. OEMs can now counter tip wetting early in the design process.

In an initial step, engineers simulate the transient flow in the injection nozzle, deploying the FIRE eulerian multiphase module. Besides insights about the flow in the nozzle itself, this gives them information about the break-up of the injected fuel and the interaction of the fuel droplets with the air in the combustion chamber. Most importantly, they also learn about the amount and exact location of the fuel droplets that attach to the nozzle tip.

Next is simulating the combustion event itself. For this, the software deploys a computational model representing intake and exhaust ports, valves, combustion chamber, piston, spark plug and of course the tip of the injection nozzle.

With the help of FIRE, simulation engineers now get a clear picture about the number, size and mass of the particles generated during combustion. This gives them the opportunity to see which design or operating parameters impact nozzle tip wetting and particle generation, and to take measures to minimize or avoid these undesired phenomena.

This is how AVL FIRE effectively contributes to meeting emission and performance targets for new “greener” engines, bringing us closer to providing combustion engines with zero impact emissions.