A theoretical assessment of fuel combustion attributes to enhance the operational envelope of HCCI engines

Master Thesis

2006

Permanent link to this Item
http://hdl.handle.net/11427/5517
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thesis_ebe_2006_londleni_sc (1).pdf (5.77 MB)
Authors
Londleni, Sibusiso C
Supervisors
Swarts, André
Yates, Andrew
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University of Cape Town

Department
Department of Mechanical Engineering
Faculty
Faculty of Engineering and the Built Environment
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Abstract
Homogeneous Charge Compression Ignition (HCCI) is an alternative internal combustion (IC) engine that can provide high efficiencies while producing ultra-low nitrous oxides (NOx) and particulate matter (PM) emissions compared to existing compression ignition (CI) and spark ignition (SI) engines. HCCI engines operate on the principle of having a dilute, premixed charge that reacts and burns volumetrically throughout the cylinder as it is compressed by the piston. The large amounts of charge dilution also dramatically reduce the peak burned gas temperatures resulting in low NOx emissions. Since there is no fuel-rich diffusion burning taking place, the PM emissions are at near zero levels. In theory, HCCI combustion can be achieved with any fuel that evaporates readily and autoignite under the conditions typically found in an internal combustion engine. In some regards, HCCI incorporates the best features of both SI and CI engine. As in a SI engine, the charge is well mixed, which minimises particulate emissions and as in a CI engine, the charge is compression ignited and has no throttling losses, which leads to high thermal efficiencies. However, unlike either of these conventional engines, the combustion occurs simultaneously throughout the combustion chamber without a flame front, eliminating the flammability limits associated with SI combustion. The HCCI engine can provide efficiencies as high as compression ignition engines while generating extremely low NOx emissions, as low as 1-5% tailpipe NOx of a conventional SI engine.
Description

Includes bibliographical references.

Keywords
Mechanical Engineering

Reference:

Londleni, S. 2006. A theoretical assessment of fuel combustion attributes to enhance the operational envelope of HCCI engines. University of Cape Town.

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