Powertrain & Energy - April 27, 2012 - 24

Alternative fuels tested
altitude

Shown are CO2 emissions of the baseline fuel (Jet A-1) as a function of engine speed at various altitudes. The FT fuel was derived from coal. Both the FT fuel and the camelina-based hydro-processed jet fuel met all the requirements of the ASTM D7566 specification for aviation turbine fuel containing synthesized hydrocarbons. The major differences between the Jet A-1 fuel and the other three fuels are that the Jet A-1 has much higher aromatic content and has a lower cetane number. The Jet A-1 fuel also has a much lower H:C mass ratio. The microturbo TRS-18 was housed inside the altitude chamber at the National Research Council Canada (NRC) research altitude test facility. The chamber is capable of simulating altitudes up to 14 km (the typical cruise altitude of many regional aircraft) and forward Mach number typical of commercial aircraft. The maximum conditioned airflow rate was 3 kg/s-1. Raw engine exhaust was extracted from the altitude chamber through stainless steel lines and was assisted with a rotary vane pump. A fraction of the exhaust was immediately diluted using an Air-Vac ejector diluter (AVR093H) to prevent condensation and to reduce particle and gaseous concentrations to appropriate levels for the analyzers to measure with good accuracy. The typical dilution ratio used during the test was about 1.9. The diluted exhaust was split and fed to different instruments. About 10 L min-1 flow was introduced through a 1-µm size cut cyclone before entering a TSI engine exhaust particle sizer (EEPS) to measure particle number size distributions. Inside the EEPS, particles were first electrically charged by a corona and then exposed to a uniform electric field, where positively charged particles were expelled toward different electrometers depending on their electrical mobility. Charges on the particles were transferred and measured by the electrometers. The current measured at various
SAE Powertrain & Energy

April 27, 2012

Powertrain & Energy - April 27, 2012

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