Gasoline and E85 Combustion Visualization and Particulate Matter Emission in a Production SIDI Engine With Optical Access

The present study analyzes the relationship of diffusion flame and PM emission of pure gasoline (E0) and E85 in a spark-ignited direct injection engine at low coolant temperature with optical access on one side of combustion chamber for high speed visualization. Different operating conditions including injection timing, ignition timing, and air-fuel ratio (lambda) with two throttle positions (high and low load) are experimented with a high speed FTIR and an Engine Exhaust Particle Sizer (EEPS) to measure the engine-out emissions. The results show that fuel types and injection timing strongly impact particle size distribution, total concentration, and total mass of PM emission due to piston or cylinder liner wall-wetting. It is concluded that both E0 and E85 present diffusion flame with early injection timing, and the existence of diffusion flame seen in the images corresponds to higher particle mass; however, it does not necessarily represent higher particle number, which is also fuel dependent. In certain conditions, PM emission of E85 could be higher in terms of particle number.© 2013 ASME