Large eddy simulation and experiments of the auto-ignition process of lean ethanol/air mixture in HCCI engines

T. Joelsson*, R. Yu, X. S. Bai, A. Vressner, Bengt Johansson

*Corresponding author for this work

Research output: Contribution to conferencePaperpeer-review

2 Scopus citations

Abstract

Recent experiments and numerical studies have showed that piston geometry has a significant effect on the homogeneous charge compression ignition (HCCI) process. There are two effects generated by the combustor geometry: the geometry affects the flow/turbulence in the cylinder; the geometry also affects the temperature stratification. The temperature stratification is more directly responsible for the observed alteration of the auto-ignition process. To clarify this issue further we present in this paper a study of two engines with the same geometry but difference ways of cooling. Measurement of the two engines-a metal engine and quartz piston engine, both with the same piston bowl geometry-is carried out. Large eddy simulation (LES) is used to simulate the flow, the temperature field and the auto-ignition process in the two engines. The fuel is ethanol with a relative air/fuel ratio of 3.3. It is found that lower temperature stratification is established in the metal engine under similar conditions as the optical quartz engine due to the more effective cooling of the piston in the metal engine configuration. The combustion phasing in the two engines is the same by controlling the intake temperature. Both measurements and LES show a more rapid auto-ignition in the metal engine than in the optical engine with the same piston geometry. This confirms the conclusion that large temperature stratification can decrease the pressure-rise-rate and thereby increase the load of HCCI engines. The dependence of temperature stratification on the wall temperature and intake temperature is systematically studied using LES.

Original languageEnglish (US)
DOIs
StatePublished - Dec 1 2008
Event2008 SAE International Powertrains, Fuels and Lubricants Congress - Shanghai, China
Duration: Jun 23 2008Jun 25 2008

Other

Other2008 SAE International Powertrains, Fuels and Lubricants Congress
CountryChina
CityShanghai
Period06/23/0806/25/08

ASJC Scopus subject areas

  • Automotive Engineering
  • Safety, Risk, Reliability and Quality
  • Pollution
  • Industrial and Manufacturing Engineering

Fingerprint

Dive into the research topics of 'Large eddy simulation and experiments of the auto-ignition process of lean ethanol/air mixture in HCCI engines'. Together they form a unique fingerprint.

Cite this