Numerical and experimental studies of homogeneous charge compression ignition engine performance

During the recent decade, an alternative combustion technology, known as Homogeneous Charge Compression Ignition (HCCI), has shown the potential to decrease both emissions and fuel consumption. In spite of its high fuel efficiency and low NOx emission compared to diesel and SI engines, HCCI combusti...

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Main Author:	Najafabadi, Mohammad Izadi
Format:	Thesis
Language:	English
Published:	2014
Subjects:	Automobiles - Ignition Automobiles
Online Access:	http://psasir.upm.edu.my/id/eprint/48196/1/FK%202014%2055R.pdf
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id	my-upm-ir.48196
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spelling	my-upm-ir.481962017-02-07T08:42:01Z Numerical and experimental studies of homogeneous charge compression ignition engine performance 2014-02 Najafabadi, Mohammad Izadi During the recent decade, an alternative combustion technology, known as Homogeneous Charge Compression Ignition (HCCI), has shown the potential to decrease both emissions and fuel consumption. In spite of its high fuel efficiency and low NOx emission compared to diesel and SI engines, HCCI combustion has some critical difficulties. The main difficulty of HCCI engine is the absence of any external control of ignition timing. Finding the effects of different parameters on the ignition timing is vital to be able to control HCCI engines. The focus of this study was to carry out a detailed numerical and experimental investigation into the factors affecting HCCI ignition timing in a 2-stroke gasoline engine. As the primary objective of this study, a Computational Fluid Dynamic (CFD) model was developed coupled to a semi-detailed chemical mechanism for the 2-stroke engine to investigate the effects of different variables such as intake temperature, air to fuel ratio, scavenging efficiency, and compression ratio on the ignition timing and emissions. As the second objective, effects of different simulation parameters such as turbulence model, grid density, and time step size were investigated to find the best method for simulation of considered engine. As the final objective, validation of numerical results was carried out using experimental study on the 2-stroke engine that was modified to operate in HCCI mode. Results confirmed that k-ε RNG model was the best turbulence model for simulation of this case study coupled to the time step size of 0.25 crank angle degree and the grid size of around 50,000 cells. Results also demonstrated that decreasing the intake temperature,equivalence ratio, residual gasses, and compression ratio can significantly retard the combustion timing and experimental results confirmed that this ignition retarding can considerably increase the engine power and torque. Automobiles - Ignition Automobiles 2014-02 Thesis http://psasir.upm.edu.my/id/eprint/48196/ http://psasir.upm.edu.my/id/eprint/48196/1/FK%202014%2055R.pdf application/pdf en public masters Universiti Putra Malaysia Automobiles - Ignition Automobiles
institution	Universiti Putra Malaysia
collection	PSAS Institutional Repository
language	English
topic	Automobiles - Ignition Automobiles
spellingShingle	Automobiles - Ignition Automobiles Najafabadi, Mohammad Izadi Numerical and experimental studies of homogeneous charge compression ignition engine performance
description	During the recent decade, an alternative combustion technology, known as Homogeneous Charge Compression Ignition (HCCI), has shown the potential to decrease both emissions and fuel consumption. In spite of its high fuel efficiency and low NOx emission compared to diesel and SI engines, HCCI combustion has some critical difficulties. The main difficulty of HCCI engine is the absence of any external control of ignition timing. Finding the effects of different parameters on the ignition timing is vital to be able to control HCCI engines. The focus of this study was to carry out a detailed numerical and experimental investigation into the factors affecting HCCI ignition timing in a 2-stroke gasoline engine. As the primary objective of this study, a Computational Fluid Dynamic (CFD) model was developed coupled to a semi-detailed chemical mechanism for the 2-stroke engine to investigate the effects of different variables such as intake temperature, air to fuel ratio, scavenging efficiency, and compression ratio on the ignition timing and emissions. As the second objective, effects of different simulation parameters such as turbulence model, grid density, and time step size were investigated to find the best method for simulation of considered engine. As the final objective, validation of numerical results was carried out using experimental study on the 2-stroke engine that was modified to operate in HCCI mode. Results confirmed that k-ε RNG model was the best turbulence model for simulation of this case study coupled to the time step size of 0.25 crank angle degree and the grid size of around 50,000 cells. Results also demonstrated that decreasing the intake temperature,equivalence ratio, residual gasses, and compression ratio can significantly retard the combustion timing and experimental results confirmed that this ignition retarding can considerably increase the engine power and torque.
format	Thesis
qualification_level	Master's degree
author	Najafabadi, Mohammad Izadi
author_facet	Najafabadi, Mohammad Izadi
author_sort	Najafabadi, Mohammad Izadi
title	Numerical and experimental studies of homogeneous charge compression ignition engine performance
title_short	Numerical and experimental studies of homogeneous charge compression ignition engine performance
title_full	Numerical and experimental studies of homogeneous charge compression ignition engine performance
title_fullStr	Numerical and experimental studies of homogeneous charge compression ignition engine performance
title_full_unstemmed	Numerical and experimental studies of homogeneous charge compression ignition engine performance
title_sort	numerical and experimental studies of homogeneous charge compression ignition engine performance
granting_institution	Universiti Putra Malaysia
publishDate	2014
url	http://psasir.upm.edu.my/id/eprint/48196/1/FK%202014%2055R.pdf
_version_	1747811965209673728

Numerical and experimental studies of homogeneous charge compression ignition engine performance

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