Crevice model
 

Hi,
I have a question regarding use of the crevice model for IC application: does it influence the compression ratio?
Example: if my engine CR is 18 (with the real geometry), but to simplify geometry for simulation I remove geometrical crevices, certainly CR increases, as the clearance volume decreases. In that case, I usually modify (increase) the squish height to obtain correct CR for simulation. However, increasing the squish height can influence the results, as spray targeting changes, etc. So, if I don't change the squish height, but instead use the crevice model, will it decrease CR?
Thank you in advance, I hope I made myself clear.

Hi,

When using the crevice model, it will not show any difference in CR in the studio since it is calculated based on the geometry. However, when the simulation is running, there will be a mass exchange between the cylinder region and modeled-crevice region that will account for the change in pressure/compression to simulate the presence of the crevice region. CONVERGE will output a file crevice.out which contains the mass in the crevice region.

Thanks,

Thank you for the answer!