Biocombustibili per applicazione su MCI

Two CFR (Cooperative Fuel Research) single cylinder engines (a spark ignition and a Diesel one) for the determination of fuel characteristics (octane or cetane number) are available among the Internal Combustion Engines Group test facilities.
Recently, CFR Diesel engine control system has been upgraded and expanded, while a data acquisition system has been set up in order to measure the main engine operating parameters and in-cylinder pressure diagrams. This engine is now used in order to characterise bio-fuels, focusing on the assessment of alternative fuels potential. Taking into account its technical characteristics, the engine is particularly suitable for basic investigations, focused on potential fields of application of these fuels such as energy generation in developing countries, aiming at the comparison of blends including high content of renewable fuels, neat biodiesels or untreated oils obtained from different feedstock. Therefore, the engine was deeply modified to enlarge its working field, enhancing speed and load control, and to make measurements of the main operating parameters on a grid of selected experimental conditions, giving extended information on fuels/blends considered, together with the standard evaluation of Cetane Number (CN) allowed by CFR engines. Taking into account the possibility of testing fuels with high values of viscosity at ambient temperature, a feeding line with an electrical heater is also available, in order to supply the engine with fuels at controlled levels of temperature.
As regards engine instrumentation, rotational speed is measured by a magnetic pick-up, properly installed in order to give the required reference and trigger signal phased with the top dead centre position, while torque is evaluated through a load cell. Main operating parameters affecting performance and emissions (air and fuel mass flow rate, intake and exhaust pressure and temperature levels, etc.) are also measured. In-cylinder pressure diagrams and injection pressure are recorded with water-cooled piezoelectric pressure transducers. The injector needle is equipped with a position sensor to assess injection advance and duration. Finally, sampling probes are properly located in the exhaust circuit in order to feed a CLA analyser and a smoke meter for NOX concentration and exhaust smoke evaluation. The whole measurement phase is managed by a compact data acquisition system (National Instrument cDAQ-9172) connected to a personal computer through an USB interface.
Among the most important engine parameters, brake thermal efficiency and brake specific NOX and soot emissions are defined through data processing, while the availability of in-cylinder pressure diagrams and related quantities allows the calculation of the experimental rate of heat release, giving an in-depth analysis of the influence of alternative fuels on combustion process.

Publications

1. Zamboni G., Marelli S., Marmorato G., Capobianco M. An experimental apparatus for testing biodiesels based on a CFR engine – Setup and validation with different methyl ester blends. International Journal of Green Energy, 2015, ISSN: 1543-5083, doi: 10.1080/15435075.2014.977439.
2. Zamboni G., Marelli S., Marmorato G., Capobianco M. Experimental comparison of different diesel-biodiesel blends in a CFR engine. Proceedings of the ASME 2012 International Mechanical Engineering Congress & Exposition (IMECE2012), Volume 6, Parts A & B-Energy, paper IMECE2012-86298, November 9-15, 2012, Houston, Texas, USA.
3. Zamboni G., Marelli S., Marmorato G., Capobianco M. Confronto sperimentale di diverse miscele diesel – biodiesel in un motore CFR.Memoria ATI1206109, 67° Congresso Nazionale ATI – Trieste, 11-14 Settembre 2012