An experimental investigation on the influence of piston bowl geometry on RCCI performance and emissions in a heavy-duty engine. (October 2015)

• Record Type: Journal Article
• Authors: Benajes, Jesús; Pastor, José V.; García, Antonio; Monsalve-Serrano, Javier
• Is Part Of: Energy conversion and management. Volume 103(2016)
• Page Start: 1019
• Page End: 1030
• Publication Date: 2015-10
• Subjects: aTDC After Top Dead Center -- BSFC Break Specific Fuel Consumption -- CAD Crank Angle Degree -- CA10 Crank angle at 10% mass fraction burned -- CA50 Crank angle at 50% mass fraction burned -- CA90 Crank angle at 90% mass fraction burned -- CDC Conventional Diesel Combustion -- CO Carbon Monoxide -- CR Compression Ratio -- DI Direct Injection -- EGR Exhaust Gas Recirculation -- EOI End of Injection -- EVC Exhaust Valve Close -- EVO Exhaust Valve Open -- FSN Filter Smoke Number -- GF Gasoline Fraction -- HC Hydro Carbons -- HCCI Homogeneous Charge Compression Ignition -- HD Heavy Duty -- IP Injection Pressure -- IVC Intake Valve Close -- IVO Intake Valve Open -- LTC Low Temperature Combustion -- ON Octane Number -- PM Particulate Matter -- 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 -- SOI Start of Injection -- VVA Variable Valve Actuation; Reactivity Controlled Compression Ignition -- EURO VI -- Efficiency -- Dual fuel -- Combustion; 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.2015.07.047
• Languages: English
• ISSNs: 0196-8904

Abstract

Highlights: Great influence of piston geometry at low load using single injection strategies. Enhanced combustion development at mid load through optimized piston surface area. Double injection allows ultra-low NOx and soot levels for the three piston geometries. Unacceptable soot emissions at high load using single injection and bathtub geometry. Stepped geometry leads to ultra-clean combustion with lower fuel consumption than CDC. Abstract: This experimental work investigates the effects of piston bowl geometry on RCCI performance and emissions at low, medium and high engine loads. For this purpose three different piston bowl geometries with compression ratio 14.4:1 have been evaluated using single and double injection strategies. The experiments were conducted in a heavy-duty single-cylinder engine adapted for dual fuel operation. All the tests were carried out at 1200 rev/min. Results suggest that piston geometry has great impact on combustion development at low load conditions, more so when single injection strategies are used. It terms of emissions, it was proved that the three geometries enables ultra-low NOx and soot emissions at low and medium load when using double injection strategies. By contrast, unacceptable emissions were measured at high load taking into account EURO VI limitations. Finally, the application of a mathematical function considering certain self-imposed constraints suggested that the more suitable piston geometry for RCCI operation is the stepped one, which has a modified transition from the center to the squish region and reduced piston surface area than the stock geometry.