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In this study, the injection spray of the IQT™ is characterized under atmospheric back pressure using phase doppler anemometry (PDA). Viscor calibration fluid, which has diesel-like fluid properties, is injected using the complete injection system of the IQT™. The high temporal resolution of the PDA method allowed precise time-resolved analysis of droplet size and velocity. The AMD and SMD of fuel droplets are found to be 9.3 and 29.3 μm, respectively. The velocity is analyzed as a function of radial position from the nozzle axis. The droplet velocity varies between 130 m/s and 10 m/s depending on spatial position and time after the start of injection. Average velocities on the axis were found to be approximately 78 m/s, decreasing to 15 m/s moving towards the outer spray periphery. The droplet count as a function of radial position suggests that most droplets form a cone angle of 12.6°, which is in agreement with a series of high speed images captured using front light photography.

This paper reports on the third part of a continued study (SAE Papers 961182, 971636) to develop the Ignition Quality Tester (IQT™). Past research has shown that this automated laboratory/refinery apparatus can be used to accurately predict the cetane number of middle distillates and alternative fuels using small sample volumes (< 50 mL). The paper reports on the main objective of a study performed by Advanced Engine Technology Ltd. (AET), in co-operation with its research partners. The primary research objective of this work is to further the understanding of fuel preparation (fuel air mixing) and start of combustion processes in the IQT™. Key to this understanding is the manner in which single molecule compounds and full boiling-range diesel fuels behave during these processes. Insights are provided into the manner in which the American Society for Testing and Materials (ASTM) D-613 primary reference fuels (PRFs) undergo fuel preparation and start of combustion in the IQT™.