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

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.

Grantor dc:publisher.institution

Department of Mechanical Engineering

Year dc:date.issued

2006

Author dc:creator

• Londleni, Sibusiso C

Advisors dc:contributor.advisor

• Swarts, André
• Yates, Andrew

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/11427/5517

OAI identifier oai:identifier

oai:open.uct.ac.za:11427/5517