Mechanism of hydrocarbon reduction using multiple injection in a natural gas fuelled/micro-pilot diesel ignition engine

Abstract

Research has shown that a large amount of natural gas (NG) is unburned at light loads in an NG fuelled/micro-pilot diesel compression ignition engine. A mechanism of unburned hydrocarbon (HC) reduction using multiple injections of micro-pilot diesel has been proposed in this paper. Multidimensional computations were carried out for a dual-fuel engine based on a modified CAT3401 engine configuration. The computations show that a split injection with a small percentage (e.g. 30 per cent of diesel in the second injection pulse) can significantly reduce HC, CO and NO_x emissions. Based on parametric studies to optimize the timing of both of the injection pulses, HC emissions could be reduced by 90 per cent, with a reduction in CO emissions of 50 per cent and NO_x emissions of 70 per cent in comparison to a single-injection pulse-base case configuration.