Robust EGR control for counteracting exhaust back-pressure fluctuation attributable to soot accumulation in a diesel particulate filter

A diesel engine comprising:

• an exhaust system comprising a diesel particulate filter (DPF) for trapping diesel particulate matter (DPM) in exhaust gas passing through the exhaust system;
• an EGR system for recirculating some exhaust gas through the engine;
• and a control system for controlling flow of exhaust gas through the EGR system in consequence of the processing of data by the control system wherein the control system
• a) processes certain data to select a data value for present EGR volumetric efficiency that is based on a predetermined relationship between certain parameters associated with operation of the engine,
• b) processes the selected data value for present EGR volumetric efficiency and certain other data, including data that accounts for present soot accumulation in the DPF, to develop a data value indicative of present total mass flow through the engine during engine operation, and
• c) processes the data value indicative of present total mass flow through the engine and still other data to develop flow control data for controlling flow of exhaust gas through the EGR system, and
• d) controls the flow of exhaust gas through EGR system in accordance with the flow control data.

A system for counteracting the effect of soot accumulation in a diesel particulate filter (DPF) in an exhaust system of a diesel engine on the control of exhaust gas recirculation (EGR) through an EGR system of the engine, the system comprising:

• a processor for processing data and performing a control function based on a result of data processing, wherein the processor
• a) processes certain data to select a data value for present EGR volumetric efficiency that is based on a predetermined relationship between certain parameters associated with operation of the engine,
• b) processes the selected data value for present EGR volumetric efficiency and certain other data, including data that accounts for present soot accumulation in the DPF, to develop a data value indicative of present total mass flow through the engine during engine operation, and
• c) processes the data value indicative of present total mass flow through the engine and still other data to develop flow control data for controlling flow of exhaust gas through the EGR system, and
• d) controls flow of exhaust gas through the EGR system based on the flow control data.