A study on pre-combustion conditions in the cooperative fuel research (CFR) engine

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Journal Title

Journal ISSN

Volume Title

Insinööritieteiden korkeakoulu | Master's thesis

Date

2020-12-14

Department

Major/Subject

Mcode

Degree programme

Nordic Master Programme in Innovative and Sustainable Energy Engineering (ISEE)

Language

en

Pages

80+7

Series

Abstract

Knocking can produce adverse effect on engine performance. When knocking combustion occurs inside the cylinder, fuel combustion efficiency decreases, fuels do not combust fully, resulting in the improvement of exhaust gas emissions. In addition, knocking causes irreversible damage to the cylinder. Therefore, it is important to understand the physical phenomena in different parts of the engine during a combustion process under different engine operation conditions. It is also important to understand fuels’ physical properties’ effects on the physical phenomena inside an engine under various operation conditions. In this study, cooperative fuels research (CFR) engine modellings under research octane number testing conditions and motor octane number testing conditions are built by using Gt-Power software. Those two modelling are employed in order to observe the pre-combustion conditions of spark ignition (SI) engine. The temperature, pressure and gaseous mass fraction variations in the intake system are simulated with the surrogate of gasoline, indolene. Variations on temperature, pressure and burnt mass fraction in the engine cylinder are simulated based on 19 kinds of fuels with different octane numbers. Density and heat of evaporation (HoV) are main parameters. Density and evaporative heat are mainly parameters for investigating the impact of fuels physical properties on the physical phenomena. The simulation results show the variation trend of pressure, temperature and gaseous mass fraction in the intake system. Besides, it is revealed by simulations that in-cylinder pre-combustion conditions are more severe with higher pressure and higher temperature when the octane number of fuels increase. Density of fuel has no significant effect on the in-cylinder pre-combustion conditions, while heat of vaporization (HoV) of a fuel can manipulate in-cylinder temperature to some extent based on simulation results.

Description

Supervisor

Larmi, Martti

Thesis advisor

Kaario, Ossi

Keywords

octane numbers, octane numbers rating, knocking, CFR engine, pre-combustion conditions, gasoline surrogates

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