Experimental Investigation of Cyclic Variability on Combustion and Emissions of a High-Speed SI Engine

Apostolos Karvountzis-Kontakiotis, Leonidas Ntziachristos, Zissis Samaras, Athanasios Dimaratos, Mark Peckham

    Research output: Chapter in Book/Report/Conference proceedingConference contributionScientificpeer-review

    15 Citations (Scopus)

    Abstract

    Cyclic combustion variability (CCV) is an undesirable characteristic of spark ignition (SI) engines, and originates from variations in gas motion and turbulence, as well as from differences in mixture composition and homogeneity in each cycle. In this work, the cycle to cycle variability on combustion and emissions is experimentally investigated on a high-speed, port fuel injected, spark ignition engine. Fast response analyzers were placed at the exhaust manifold, directly downstream of the exhaust valve of one cylinder, for the determination of the cycle-resolved carbon monoxide (CO) and nitric oxide (NO) emissions. A piezoelectric transducer, integrated in the spark-plug, was also used for cylinder pressure measurement. The impact of engine operating parameters, namely engine speed, load, equivalence ratio and ignition timing on combustion and emissions variability, was evaluated. The variations in mixture stoichiometry were found to have a strong effect on engine combustion variability. Rich cyclic mixture compositions exhibit lower coefficient of variation (COV) for the indicated mean effective pressure (IMEP) and NO emissions (COVNO) compared with lean mixtures. The mean value of CO emission was found to be mainly affected by stoichiometry while COVCO is affected by lambda fluctuations. At higher engine loads, maximum cylinder pressure and IMEP are increased, while COVIMEP decreased. Furthermore, ignition timing was found to strongly affect combustion and NO emissions, as it is related with early flame kernel development and thereby with flame propagation. Maximum braking torque (MBT) operation exhibits maximum IMEP and minimum COVIMEP. Compared to MBT operating conditions, advanced ignition timing leads to higher maximum cylinder pressure, higher NO and COVNO, while retarded ignition timings lead to lower maximum cylinder pressure, lower NO concentration and higher NO variability (COVNO).

    Original languageEnglish
    Title of host publicationSAE 2015 World Congress and Exhibition
    PublisherSAE International
    Volume2015-April
    EditionApril
    DOIs
    Publication statusPublished - 14 Apr 2015
    Publication typeA4 Article in conference proceedings
    EventSAE 2015 World Congress and Exhibition - Detroit, United States
    Duration: 21 Apr 201523 Apr 2015

    Conference

    ConferenceSAE 2015 World Congress and Exhibition
    Country/TerritoryUnited States
    CityDetroit
    Period21/04/1523/04/15

    ASJC Scopus subject areas

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

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