Environmental standards concerning Suspended Particulate Matter (SPM) are continuously becoming stricter. The light-duty diesel passenger car market is rapidly increasing due to performance improvements and the economic advantages of the diesel engine. To meet EURO 4 diesel passenger car emission regulations, regeneration experiments of a catalyzed particulate filter (CPF) system have been performed with 2.0L common-rail diesel engine.
For effective regeneration of the CPF system, we investigated the effects of various regeneration conditions on the system. Conditions such as exhaust gas temperature, oxygen/hydrocarbon concentrations, gas compositions, etc. were investigated.
We found that the regeneration efficiency was improved when the exhaust gas temperature increased to more than 700°C during CPF regeneration using engine post injection. An additional amount of post injection increased the exhaust gas temperature and residual hydrocarbon content. The increase of residual hydrocarbon content closely affected the CPF internal temperatures. Furthermore, the oxygen content of the exhaust gas closely affected the control of CPF internal temperatures.
Depending on how these factors (temperature, hydrocarbon amount, oxygen content) were varied, the regeneration results were very different. We found that these factors were closely related to regeneration efficiency, regeneration duration, system durability, etc. Also, we evaluated the common-rail engine parameters such as fuel injection timing and quantity.
Throughout this study, we focused on establishing and optimizing the regeneration strategy for the catalyzed diesel particular filter system. Based on the evaluation results, we established the regeneration strategy and optimized the CPF system regeneration properties.