Pre-chamber combustion system for heavy-duty engines for operating dual fuel and diesel modes

Abstract

With the increase in heavy-duty engines, an enhanced combustion concept is necessary to meet stringent environmental regulations. Pre-chamber combustion systems can be used to improve combustion stability and emissions, and their design parameters are important because they affect the jet properties and engine performance. Therefore, this study investigates the combustion and emission characteristics of a pre-chamber combustion system for heavy-duty engines using a CFD program to determine the optimal design for engine performance. The simulation was conducted with an engine speed of 720 rpm and a 100% load condition for both dual fuel and diesel-only operation modes. Results indicate that the optimal pre-chamber nozzle design parameters include a hole diameter of 2.4 cm, 4 holes, and a direction angle of 60 deg. Compared with a conventional engine, the gross IMEP for an engine with a pre-chamber combustion system increased up to 0.8%, and the THC emissions was significantly reduced by preventing methane slip in dual-fuel mode. Additionally, NOx production was reduced by 50% in diesel mode. However, the NOx in dual-fuel mode and the soot in diesel mode were deteriorated. Therefore, engine operating strategies for pre-chamber combustion systems should be investigated as future work.