Medium and high load performance of partially premixed combustion in a wave-piston multi-cylinder engine with diesel and PRF70 fuel

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title = "Medium and high load performance of partially premixed combustion in a wave-piston multi-cylinder engine with diesel and PRF70 fuel",
abstract = "European and US emission legislation on diesel compression ignition engines has pushed for the development of new types of combustion concepts to reduce hazardous pollutants and increase fuel e ciency. Partially premixed combustion (PPC) has been proposed as one solution to future restrictions on emissions while providing high gross indicated e ciency. The conceptual idea is that the time for the mixing between fuel and air will be longer when ignition delay is increased by addition of high amounts of exhaust gas recirculation (EGR). Increased air-fuel mixing time will lead to lower soot emissions and the high EGR rates will reduce both NOx emissions and combustion flame temperature, which decreases the overall heat transfer. Previous research in heavy-duty gasoline PPC has mostly focused on emissions and e ciency at low and medium load in single-cylinder engines. In this paper a Volvo D13 heavy-duty single-stage VGT engine with a newly developed Wave piston was run at medium and high engine load with a variation in fuel injection pressure. The Wave piston was specifically designed to enhance air-fuel mixing and increase combustion velocity. Two fuels were used in the experiments, PRF70 and Swedish MK1 diesel. Soot-NOx trade-o, combustion characteristics and e ciency were compared for both fuels at 1000 and 2000 Nm engine torque. The results show that at high load the combustion behavior with respect to rate of heat release and heat transfer is very similar between the fuels and no major di erence in indicated e ciency could be observed. Peak gross indicated e ciencies were reported to be around 49 % for both fuels at 1000 Nm and slightly above 50 % at 2000 Nm. The new Wave piston made it possible to obtain 1 g/kWh engine-out NOx emissions while still complying with Euro VI legislation for particulate emissions. Soot emissions were generally lower for PRF70 compared to MK1 diesel. We could also conclude that gas exchange performance is a major issue when running high load PPC where high λ and EGR is required. The single-stage VGT turbocharger could not provide su cient boost to keep λ above 1.3 at high EGR rates. This penalized combustion e ciency and soot emissions when reaching Euro VI NOx emission levels (0.3-0.5 g/kWh).",
author = "Kenan Muric and Per Tunestal and Ingemar Magnusson",
year = "2018",
doi = "10.1115/ICEF2018-9568",
language = "English",
volume = "1",
booktitle = "Large Bore Engines; Fuels; Advanced Combustion",
publisher = "American Society Of Mechanical Engineers (ASME)",
address = "United States",
note = "ASME 2018 Internal Combustion Engine Division Fall Technical Conference, ICEF 2018 ; Conference date: 04-11-2018 Through 07-11-2018",