Convergent Science

Spark Ignited Gasoline Engines

CONVERGE™ is ideally suited for gasoline engine simulations, including Port Fuel Injection (PFI) and Gasoline Direct Injection (GDI) designs. Features such as easy inclusion of complex geometries, the SAGE detailed chemistry solver and adaptive mesh refinement allow for fast simulation setup and accurate results.

The example below illustrates the use of CONVERGE™ for simulating a GDI engine operating in homogeneous mode. Starting from the CAD geometry definition, the case was up and running in only 2-3 hours. This setup time was spent flagging the surfaces for boundary conditions and setting up the input files (injection specification, valve-lift profiles, etc.). Since the grid is created at runtime in CONVERGE™, no time was spent creating the computational mesh.

The image below shows velocity magnitude in a cut-plane through one of the intake valves. The mesh is also shown to illustrate the use of adaptive mesh refinement to accurately capture the flow structures.

si_converge_vel

 

 

Fuel is injected during the intake stroke, as shown in the image below. In this case a pressure-swirl atomizer is modeled using CONVERGE™’s suite of spray models.

 

si_converge_spray

 

After the fuel has vaporized and mixed with the air, the near-stoichiometric mixture is ignited. Detailed chemistry is used to model the combustion event, and adaptive mesh refinement is included to accurately model the flame propagation. The image below shows a cut-plane colored by temperature. Grid lines are included to illustrate the use of AMR to track the flame front.

 

si_converge_flame

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