Experimental Research On The Exhaust Heat Management Strategy Of Diesel Engine To Meet Bei Beijing 5+ Emission Regulation

The Beijing 5+ diesel engine will used in public transportation and must meet the WHTC cycle emission requirement. But the engine speed and load been low in the actual utilization and test process, thus engine exhaust temperature is low. At present, the general technical routes of Beijing 5+ diesel engine are the interior purification, DOC, DPF and SCR after treatment systems. In order to reduce the engine fuel consumption, the passive regeneration of DOC+DPF after treatment system should be enhanced. And the direct method is improving the temperature of DOC+ DPF after treatment system.Relative to Chinese 4 emission regulation, The Beijing 5+ diesel engine SCR system needs to improve converter efficiency. But SCR catalyst is arranged after DPF. So there have some exhaust heat energy has los t. In order reach the high converter efficiency, not only improve SCR catalyst, but also take some measures to improve SCR catalyst temperature. So some exhaust thermal management measures should be taken because of the design factors of Beijing 5 +diesel engine for improving diesel engine exhaust temperature at low speed and load.In this paper, the experimental researches have been conducted on the Beijing 5+ diesel in order to increase exhaust temperature. The principle of some technologies, exhaust temperature improving capacity and the impacts on diesel engine performance have been introduced. And the treatment measures impacts on SCR and DPF improving efficiency have been also introduces. The main research work and innovation points as follows.(1) The technical routes of EGR+DOC+DPF and DOC+DPF+SCR have been studied, the results showed that the interior purification, DOC +DPF+SCR after treatment systems, and together with the exhaust thermal management technology can meet the requirements of Beijing 5+ diesel public transportation WHTC cycle emission.(2) According to the requirements of Beijing 5+ diesel public transportation WHTC cycle emission, the scheme of exhaust thermal management system has been designed to achieve the technical route. And verification tests have been developed, including experiment plan, condition, process and steps. These established a stable foundation for Beijing 5+ diesel public transportation WHTC cycle emission experiments.(3) The influence of interior purification, DOC+DPF+SCR after treatment systems Beijing 5+ diesel public transportation to postprocessor temperature has been studied. The influence rules of fuel injection advance angle, throttle valve, exhaust restrictor and exhaust pipe thermal insulation to engine power performance, fuel consumption and NOx emissions have been revealed.