Influence of Diesel Engine Intake Throttle and Late Post Injection Process on the Rise of Temperature in the Diesel Oxidation Catalyst

In order to effectively implement DPF (Diesel Particulate Filters) regeneration control, thermal management of exhaust products before and inside Diesel Oxidation Catalyst (DOC) is necessary. In the present study, the Influence of the intake throttle valve and late post injection process on temperature rise inside DOC is analyzed through engine bench tests. The steady experiment results show that adjustment of the intake throttle valve can effectively increase exhaust temperature before DOC; in particular, with intake throttle valve opening at 20%, temperature before DOC can be increased by about 170 degrees C with respect to the full opening. An increase in the late post injection quantity can produce a significant rise of the temperature inside DOC, however its impact on the exhaust temperature before DOC is relatively limited. As the late post injection quantity increases, Hydrocarbon (HC) emissions also grow; in the present work it is shown that with a proper injection quantity, a considerable temperature increase inside the DOC can be obtained with relatively low HC emission. More specifically, with the intake throttle valve at 30% and DOC reaching ignition temperature as the late post injection quantity is increased, the exhaust temperature after DOC can be made larger than 550 degrees C, adequate for DPF active regeneration.