In order to resolve global atmospheric environmental issues, latest diesel engines for industrial machinery are required to reduce the emission of harmful gases such as carbon monoxide (CO), hydrocarbon (HC) and nitrogen oxide (NOx), and particulate matter (PM). For this reason, it is essential to mount exhaust gas after treatment devices such as diesel particulate filter (DPF) and diesel oxidation catalyst (DOC) on diesel engine. Engines mounted DPF must carry out DPF regeneration that burns and removes PM. Generator engine has characteristic of being operated for a long time under light load condition with low exhaust temperature which is difficult for DPF regeneration. In addition, generating white smoke and inlet face clogging of DOC are caused by accumulated soot containing HC at the DOC when operating engine continuously under light load condition.
In this study, DPF regeneration system suitable for generator engine and method for preventing white smoke and inlet face clogging of DOC is proposed by installing Pre-heating catalyst and exhaust throttle valve on upstream of DOC. Exhaust heating control using Pre-heating catalyst and exhaust throttle valve enables DPF regeneration in all cases of operating conditions including operation without load. In addition, HC accumulation that causes white smoke is prevented by periodically raising temperature of DOC by exhaust heating control. Furthermore, method for burning and removing clogging matter on DOC inlet face caused by light load operation is developed, making it possible to prevent inlet face clogging of DOC.
