Clean and efficient dual-fuel combustion using OMEx as high reactivity fuel: Comparison to diesel-gasoline calibration. (15th July 2020)

• Record Type: Journal Article
• Authors: Benajes, Jesús; García, Antonio; Monsalve-Serrano, Javier; Sari, Rafael
• Is Part Of: Energy conversion and management. Volume 216(2020)
• Publication Date: 2020-07-15
• Subjects: Reactivity controlled compression ignition -- Dual-fuel combustion -- Oximethylene ether -- EURO VI emissions -- Synthetic fuels; ASTM American Society of Testing and Materials -- ATDC After Top Dead Center -- CAD Crank Angle Degree -- CA50 Crank angle at 50% mass fraction burned -- CDC Conventional Diesel Combustion -- CO Carbon Monoxide -- CR Compression Ratio -- DI Direct Injection -- DPF Diesel Particulate Filter -- ECU Electronic Control Unit -- EGR Exhaust Gas Recirculation -- EVO Exhaust Valve Open -- FSN Filter Smoke Number -- HC Hydro Carbons -- HCCI Homogeneous Charge Compression Ignition -- IMEP Indicated Mean Effective Pressure -- IVC Intake Valve Close -- IVO Intake Valve Open -- LTC Low Temperature Combustion -- MCE Multi Cylinder Engine -- OEM Original Equipment Manufacturer -- ON Octane Number -- PFI Port Fuel Injection -- PPC Partially Premixed Charge -- PRR Pressure Rise Rate -- RCCI Reactivity Controlled Compression Ignition -- RoHR Rate of Heat Release -- SOC Start of Combustion -- SCE Single Cylinder Engine -- SCR Selective Catalytic Reduction; Direct energy conversion -- Periodicals; Energy storage -- Periodicals; Energy transfer -- Periodicals; Énergie -- Conversion directe -- Périodiques; Direct energy conversion; Periodicals; 621.3105
• DOI: 10.1016/j.enconman.2020.112953
• Languages: English
• ISSNs: 0196-8904

Abstract

Highlights: Dual-fuel engine calibrated using diesel-gasoline and OMEx-gasoline pair of fuels. Soot values under the detection limit with OMEx-gasoline for all the engine map. NOx emissions reduced with OMEx by using higher EGR levels without soot penalty. Higher efficiency with OMEx due to lower pumping losses and better combustion control. Abstract: From previous results in a single-cylinder engine platform, it can be concluded that the dual-mode dual-fuel (DMDF) concept can be a potential solution to overcome the major constraints found with other single-fuel low temperature combustion modes. To extend these findings to a real application, this work evaluates the potential of the diesel-gasoline DMDF concept on a multi-cylinder 8L engine in terms of performance and emissions. To do this, a full engine calibration map was obtained following a specific methodology. The emissions results show that diesel-gasoline DMDF allows to achieve EURO VI NOx and soot emissions in a great portion of the engine map. Nonetheless, the levels of these pollutant at high load conditions exceed the EURO VI limits by far due to the need of implementing a diffusive combustion strategy with high EGR levels to avoid excessive in-cylinder pressure gradients. To mitigate this issue, the use of Oxymethylene ether (OMEx) instead of diesel fuel is proposed. A dedicated engine calibration was developed for the OMEx-gasoline DMDF concept following the same methodology. The results show that the oxygen content in the OMEx molecule allows to achieve a fully EUVI compliant engine calibration in terms of NOx with engine-out soot levels lower than 0.01 g/kWh. Moreover, due to the lower stoichiometric air–fuel ratio with this fuel, the air management system requirements are lower, reducing the pumping losses and increasing the brake thermal efficiency in most of the calibration map.