Pressure drop model development in Gasoline Particulate Filters for model based calibration
2022-01-0674
03/29/2022
- Event
- Content
- Gasoline Particulate Filters (GPF) are widely employed in exhaust aftertreatment systems of gasoline engines to meet the stringent particulate emissions requirements of Euro6 and China6 standard. While providing an effective filtration of particles, the GPF increases the engine backpressure as a penalty. The pressure drop across GPF is an important performance characteristic which drives design decisions and lot of effort is spent on calibrating the same on dyno and vehicle level. A physics based back pressure predictive tool can help in reducing the hardware testing. In the present work, the development of a pressure drop model across the GPF using GT-Power for various conditions like clean, soot loaded and ash filled is described. Firstly, clean filter brick parameters like wall permeability and Forchheimer constant are fitted using bench data and then validated with dyno conditions. To fit soot parameters like soot permeability and soot density, pressure drop data under dyno conditions with different soot loads is used. The parameters are calibrated for average soot loads and validated for low and high soot conditions. Soot density is specified as a function of soot load and flow Peclet number to consider the effect of soot compression. Effect of break-in or filter aging is included in the model for accurate pressure drop prediction under real driving conditions. The pressure drop predictions under various soot loaded conditions are found to be in good agreement with test data obtained from vehicle conditions. Finally, the model parameters are fitted for ash loaded conditions. Ash parameters like permeability, ash layer density and ash mass proportion in cake and plug are validated against test data from dynamometer. With the validated pressure drop model, a parametric study has been performed to study the effect of ash parameters and the results follow the trends observed in literature. The model is applied to filters with same brick and different cone designs by modifying cone parameters in GT-Power. The model has been validated for different engine programs over a wide range of test conditions on engine dynamometer and vehicle. The model is applied for making design decisions like selection of after-treatment architecture and GPF sizing for the specified engine program and also for populating the required pressure drop calibration tables
- Citation
- Kannan, R., Ramappan, V., Mehta, Z., Govindula, S. et al., "Pressure drop model development in Gasoline Particulate Filters for model based calibration ," SAE Technical Paper 2022-01-0674, 2022, .