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Diesel Dual Fuel (DDF) operation is a promising alternative engine operating mode. Previous research studies have reported a DDF engine operating under low load conditions suffers from high HC emissions, mostly Methane. The current study investigated the use of a multiple direct injection strategy for improvement of low-load DDF operation in a commonrail direct injection single-cylinder diesel engine. Natural gas was supplied at 70% of energy replacement ratio. Results indicated that depending on engine conditions, a double-pulse injection had potential for combustion control and provided an effective way to reduce NOx and methane emissions. Moreover, the double-pulse injection helped improve the combustion stability, reduce the pressure rise rate, and decrease the maximum cylinder pressure, compared to DDF operation with a single pulse injection.

Particulate Matter (PM) is one of the world’s most problematic pollutants in terms of harm to environment and human health. It has been found out that PM emission levels are very high during traffic congestion and thus, PM is considered as the primary pollutants in city areas. Many literatures suggested that PM emitted during braking sequence from both internal combustion engines and electrified vehicles are considered high and could be the major cause of this issue. Many studies regarding to PM from brake wear were done in the pin disc laboratory setup with a brake dynamometer that might not represent real-world driving scenarios. Various studies of on road non-exhaust PM measurement were mostly focused on driving cycles. Parametric studies to identifying factors that affect brake wear during real-world driving scenarios are still needed for more investigations.

The diesel/natural gas engine configuration provides a potential alternative solution for PM and NOx emissions reduction from typical diesel engine operations. However, their engine operations suffer from high NMHC/methane emissions and poor engine performance, especially at light loads. By increasing the diesel pilot quantity, the performance and reduction of NMHC/methane emissions can be improved but the emission levels are still very high. Clearly, a typical DOC is not good enough to treat NMHC/methane emissions. Methane has been known as one of most stable species that is difficult to catalytically oxidize in lean burn environment and low exhaust temperatures. An aftertreatment system exclusively designed for treating methane emissions from DDF operations is therefore necessary. The current work is aimed to establish an effective computational tool in order to study the newly proposed catalytic converter system concept on treating methane from DDF operations.