A RCCI operational limits assessment in a medium duty compression ignition engine using an adapted compression ratio. (15th October 2016)

• Record Type: Journal Article
• Authors: Benajes, Jesús; Pastor, José V.; García, Antonio; Boronat, Vicente
• Is Part Of: Energy conversion and management. Volume 126(2016)
• Page Start: 497
• Page End: 508
• Publication Date: 2016-10-15
• Subjects: ASTM American Society of Testing and Materials -- ATDC after top dead center -- CAD crank angle degree -- CA10 crank angle at 10% mass fraction burned -- CA50 crank angle at 50% mass fraction burned -- CDC conventional diesel combustion -- CI compression ignition -- CO carbon monoxide -- CR compression ratio -- DI direct injection -- DPF diesel particulate filter -- ECU engine control unit -- EGR exhaust gas recirculation -- EOI end of injection -- EU European union -- EVO exhaust valve open -- FPGA field-programmable gate array -- FSN Filter Smoke Number -- HC hydro carbons -- HD heavy-duty -- HCCI homogeneous charge compression ignition -- MCE multi cylinder engine -- MPRR maximum pressure rise rate -- IMEP indicated mean effective pressure -- ISFC indicated specific fuel consumption -- IVC intake valve close -- IVO intake valve open -- LHV lower heating value -- LTC low temperature combustion -- MON motor octane number -- OEM original equipment manufacturer -- ON octane number -- PCI peripheral component interconnect -- PER premixed energy ratio -- PFI port fuel injection -- PPC partially premixed charge -- PRR pressure rise rate -- PXI PCI eXtensions for Instrumentation -- RCCI reactivity controlled compression ignition -- RoHR rate of heat release -- RON research octane number -- SC screw compressor -- SCE single cylinder engine -- SCR selective catalytic reduction -- SOC start of combustion -- SOI start of injection -- TDC top dead center; RCCI (Reactivity controlled compression ignition) -- Euro VI limits -- CDC (Conventional Diesel Combustion) -- Commercial fuels -- Compression ratio; 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.2016.08.023
• Languages: English
• ISSNs: 0196-8904

Abstract

Highlights: RCCI with CR 12.75 reaches up to 80% load fulfilling mechanical limits. Ultra-low levels in NOx and soot emissions are obtained in the whole engine map. Ultra-high levels of CO and uHC have been measured overall at low load. RCCI improves fuel consumption from 25% to 80% engine loads comparing with CDC. Abstract: Reactivity Controlled Compression Ignition concept offers an ultra-low nitrogen oxide and soot emissions with a high thermal efficiency. This work investigates the capabilities of this low temperature combustion concept to work on the whole map of a medium duty engine proposing strategies to solve its main challenges. In this sense, an extension to high loads of the concept without exceeding mechanical stress as well as a mitigation of carbon oxide and unburned hydrocarbons emissions at low load together with a fuel consumption penalty have been identified as main Reactivity Controlled Compression Ignition drawbacks. For this purpose, a single cylinder engine derived from commercial four cylinders medium-duty engine with an adapted compression ratio of 12.75 is used. Commercial 95 octane gasoline was used as a low reactivity fuel and commercial diesel as a high reactivity fuel. Thus, the study consists of two different parts. Firstly, the work is focused on the development and evaluation of an engine map trying to achieve the maximum possible load without exceeding a pressure rise rate of 15 bar/CAD. The second part holds on improving fuel consumption and carbon oxide and unburned hydrocarbons emissions at low load. Results suggest that it is possible to achieve up to 80% of nominal conventional diesel combustion engine load without overpassing the constraints of pressure rise rate (below 15 bar/CAD) and maximum pressure peak (below 190 bar) while obtaining ultra-low levels of nitrogen oxide and soot emissions. Regarding low load challenges, it has developed a particular methodology sweeping the gasoline-diesel blend together with intake temperature or exhaust gas recirculation maintaining constant the combustion phasing and ultra-low nitrogen oxide and soot emissions. As a result a drastic decrease carbon oxide and unburned hydrocarbons emissions is obtained with a slight fuel consumption improvement.