Study on dual fuel combustion in an optical research engine by infrared diagnostics varying methane quantity and engine speed

Dual fuel combustion represents a possible solution for decreasing the emission produced by diesel engine, while maintaining the efficiency rate at comparable values. In this activity, methane and diesel are used for dual fuel combustion. Methane is injected in the intake manifold, when the intake valves are closed; meanwhile the diesel is delivered directly into the cylinder. The aim of this work is to study the effect of increasing methane concentration at two engine speeds (1500 and 2000 rpm, respectively), on the start and evolution of dual fuel combustion in a compression ignition research engine using infrared diagnostics. Infrared diagnostic has the advantage of being not intrusive, it gives a high spatial and temporal resolution of combustion phenomenon and it is able to qualitatively identify the local concentration of chemical species. Infrared camera detects the energy that the target emits as electromagnetic