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

Research output: Chapter in Book/Report/Conference proceedingPaper in conference proceeding

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).

Details

Authors
Organisations
External organisations
  • Volvo Technology AB
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Vehicle Engineering
Original languageEnglish
Title of host publicationLarge Bore Engines; Fuels; Advanced Combustion
PublisherAmerican Society Of Mechanical Engineers (ASME)
Volume1
ISBN (Electronic)9780791851982
Publication statusPublished - 2018
Publication categoryResearch
Peer-reviewedYes
EventASME 2018 Internal Combustion Engine Division Fall Technical Conference, ICEF 2018 - San Diego, United States
Duration: 2018 Nov 42018 Nov 7

Conference

ConferenceASME 2018 Internal Combustion Engine Division Fall Technical Conference, ICEF 2018
CountryUnited States
CitySan Diego
Period2018/11/042018/11/07