Determining post-injection quantities in an engine with a diesel oxidation catalyst (DOC), eg for diesel particulate filter (DPF) regeneration

摘要

The invention provides a method of operating an engine having a diesel oxidation catalyst (DOC) and configured to post-inject a quantity of fuel into a combustion chamber, eg to perform diesel particulate filter (DPF) regeneration. The method comprises the steps of: (i) determining an open loop post-injection quantity qpost_OLof fuel as a function of a target temperature TOtargetfor the DOC outlet; (ii) determining the current temperature To at the DOC outlet and (iii) determining, for the temperature TO, a closed loop post-injection quantity qpost_cL, of fuel needed for correcting the open loop post-injection quantity qpost_OLfor determining a correct post-injection fuel quantity qpostneeded to match the desired DOC heat release related to the target temperature TOtargetwhen operating the engine system.