Experimental and Numerical Assessment of Active Pre-chamber Ignition in Heavy Duty Natural Gas Stationary Engine

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

Abstract

Gas engines (fuelled with CNG, LNG or Biogas) for generation of power and heat are, to this date, taking up larger shares of the market with respect to diesel engines. In order to meet the limit imposed by the TA-Luft regulations on stationary engines, lean combustion represents a viable solution for achieving lower emissions as well as efficiency levels comparable with diesel engines. Leaner mixtures however affect the combustion stability as the flame propagation velocity and consequently heat release rate are slowed down. As a strategy to deliver higher ignition energy, an active pre-chamber may be used. This work focuses on assessing the performance of a pre-chamber combustion configuration in a stationary heavy-duty engine for power generation, operating at different loads, air-to-fuel ratios and spark timings. The engine was originally a 6-cylinder compression ignition engine which is here employed as a single cylinder engine and then suitably modified to host the pre-chamber (with its natural gas injection system and spark plug) with a new bowl piston to decrease compression ratio. A 0D model is built to make a thermodynamic analysis to characterize the local conditions in the pre-chamber before spark timing (temperature, pressure and composition), based on a compressible nozzle equation for the mass transfer between the chambers and a simplified Woschni model for the pre-chamber's heat transfer. A mathematical expression was found to describe the relationship between the local conditions and the early stage of the combustion. Experimental results showed the beneficial effect of spark delay and mixture leaning for the reduction of NOx emissions, while CO, unburned hydrocarbons and engine performance see improvement with lower air-to-fuel ratios and spark advance.

Details

Authors
  • Gessica Onofrio
  • Changle Li
  • Pablo Garcia Valladolid
  • Joaquin De La Morena
  • Antonio Garcia
  • Per Tunestal
  • Carlo Beatrice
Organisations
External organisations
  • CNR Istituto Motori (IM)
  • Polytechnic University of Valencia
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Energy Engineering
  • Vehicle Engineering
Original languageEnglish
Title of host publicationWCX SAE World Congress Experience
PublisherSociety of Automotive Engineers
Volume2020-April
Publication statusPublished - 2020 Apr 14
Publication categoryResearch
Peer-reviewedYes
EventSAE 2020 World Congress Experience, WCX 2020 - Detroit, United States
Duration: 2020 Apr 212020 Apr 23

Publication series

NameSAE Technical Papers
PublisherSociety of Automotive Engineers
ISSN (Print)0148-7191

Conference

ConferenceSAE 2020 World Congress Experience, WCX 2020
CountryUnited States
CityDetroit
Period2020/04/212020/04/23