Homogeneous charge compression ignition combustion - a new promising combustion technology for internal combustion engine

The Homogeneous Charge Compression Ignition (HCCI) combustion is a new and promising technology for the Internal Combustion Engine. In a HCCI engine, the fuel is premixed to create a homogeneous charge, similar to the Spark Ignition (SI) engine. During the compression stroke, the charge is heated to achieve auto-ignition throughout the cylinder, similar to the Compression Ignition (CI) engine. The HCCI engine has been described as a hybrid of a SI and CI engine. The HCCI engine is considered as a promising alternative to the existing SI engine and Cl engine due to its remarkable advantages. The major advantages with HCCI are extremely lower NOx emissions in combination with significantly less soot formation while maintaining higher fuel efficiency at part load conditions. In addition, no throttling or high-pressure fuel injection system is needed, which also results in better efficiency and low cost. In this paper, the main types of HCCI engines are described. The basic characteristics, including combustion and emission characteristics, are also analyzed. Some challenges associated with the successful operation of HCCI engines are presented and analyzed, meanwhile some solutions have been proposed to overcome these difficulties. The future development and application of HCCI are also described.