Investigation into Different DPF Regeneration Strategies Based on Fuel Economy Using Integrated System Simulation

摘要

An integrated system model containing sub-models for a multi-cylinder diesel engine, NO_x and soot (PM) emissions, diesel oxidation catalyst (DOC) and diesel particulate filter (DPF) has been developed to simulate the engine and aftertreatment systems at transient engine operating conditions. The objective of this work is two-fold; ensure correct implementation of the integrated system-level model and apply the integrated model to understand the fuel economy trade-off for various DPF regeneration strategies. The current study focuses on a 1.9L turbocharged diesel engine and its exhaust system. The engine model was built in GT-Power and validated against experimental data at full-load conditions. The DPF model is calibrated for the current engine application by matching the clean DPF pressure drop for different mass flow rates. Load, boost pressure, speed and EGR controllers are tuned and linked with the current engine model. DPF soot loading and the impact of backpressure on engine performance is captured. DPF regeneration studies are carried out by using fuel injection ahead of the DOC and various regeneration strategies are explored. Delaying regeneration and increased loading of PM in DPF is of particular interest, as it causes an increase in back pressure and subsequently higher fuel penalty. During regeneration there is an extra penalty on fuel economy due to fuel injection ahead of the DOC. This study shows the effect of various DPF loading and regeneration strategies based on fuel economy. For a sample case study considered, fuel penalty associated with regeneration is reduced with delayed regeneration and higher PM loadings of the DPF. An energy budget analysis shows that this is due to the energy required to heat the substrate to soot regeneration temperature.