%0 Journal Article %T Homogeneous Charge Compression Ignition Combustion: Challenges and Proposed Solutions %A Mohammad Izadi Najafabadi %A Nuraini Abdul Aziz %J Journal of Combustion %D 2013 %I Hindawi Publishing Corporation %R 10.1155/2013/783789 %X Engine and car manufacturers are experiencing the demand concerning fuel efficiency and low emissions from both consumers and governments. Homogeneous charge compression ignition (HCCI) is an alternative combustion technology that is cleaner and more efficient than the other types of combustion. Although the thermal efficiency and emission of HCCI engine are greater in comparison with traditional engines, HCCI combustion has several main difficulties such as controlling of ignition timing, limited power output, and weak cold-start capability. In this study a literature review on HCCI engine has been performed and HCCI challenges and proposed solutions have been investigated from the point view of Ignition Timing that is the main problem of this engine. HCCI challenges are investigated by many IC engine researchers during the last decade, but practical solutions have not been presented for a fully HCCI engine. Some of the solutions are slow response time and some of them are technically difficult to implement. So it seems that fully HCCI engine needs more investigation to meet its mass-production and the future research and application should be considered as part of an effort to achieve low-temperature combustion in a wide range of operating conditions in an IC engine. 1. Introduction Although electric and hybrid vehicles (EVs and PHEVs) have emerged on the market, still the internal combustion engines are the most popular automotive power plant. However, in recent decades, serious concerns have piled up considering the environmental impact of the gaseous and particulate emissions arising from operation of these engines. As a result, ever tightening legislation, that restricts the levels of pollutants that may be emitted from vehicles, has been introduced by governments around the world. In addition, concerns about the worldĄŻs finite oil reserves and emissions have led to heavy taxation of road transport, mainly via on duty on fuel. These factors have led to massive pressure on vehicle manufacturers to research, develop, and produce ever cleaner and more fuel-efficient vehicles [1]. Over the last decade, an alternative combustion technology, commonly known as homogeneous charge compression ignition (HCCI), has emerged and it has the potential to decrease emissions and fuel consumption in transportation [2, 3]. HCCI is a clean and high efficiency technology for combustion engines that can be scaled to any size-class of transportation engines as well as used for stationary applications [4]. These benefits of HCCI (especially relative to spark ignition %U http://www.hindawi.com/journals/jc/2013/783789/