Experimental study of knocking phenomenon in different gasoline–natural gas combinations with gasoline as the predominant fuel in a SI engine

Autor: Ebrahim Abdi Aghdam, Reza Behrad, Hadi Ghaebi
Rok vydání: 2019
Předmět:
Zdroj: Journal of Thermal Analysis and Calorimetry. 139:2489-2497
ISSN: 1588-2926
1388-6150
DOI: 10.1007/s10973-019-08579-w
Popis: The disadvantages of the separate use of gasoline and CNG pose great challenges to the development of spark ignition (SI) engines. One of the major obstacles to achieving higher thermal efficiency in gasoline engines is the knocking phenomenon. One solution to tackle this problem is the use of a combination of gasoline and CNG. Gasoline can be used as the predominant fuel due to having higher burning velocity. In the current study, different fuel mixtures containing 100%, 90%, 80%, and 70% gasoline and the rest NG (G100, G90, G80, and G70, respectively) were investigated in a single-cylinder SI research engine. The aim was to investigate the knocking features of the mixtures at the stoichiometric equivalence ratio, the compression ratio of 11, and the engine speed of 1800 rpm. After capturing data for each mixture at every spark advance and analyzing 400 subsequent cycles, the required processes were performed to determine the knocking features of the combinations at Optimum Spark Advances (OSA). At the OSA of G100, the average maximum amplitude of pressure oscillation $$(\overline{\text{MAPO}}_{\text{Tot}} )$$ and the knocking cycle percentage (%KC) were found to be 0.289 bar and 5.3%, respectively, and the distance between OSA and the impending knock limit advance (Δθ) was found to be less than 1 °CA. With the increase in NG proportion in the fuel mixture, $$\overline{\text{MAPO}}_{\text{Tot}}$$ and %KC decreased significantly, as their values in G80 reached 0.156 bar and 0.5%, respectively. Furthermore, as NG fraction increased, Δθ also increased significantly as its value reached 4.5 °CA in G70.
Databáze: OpenAIRE
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