A Review on Homogeneous Charge Compression Ignition and Low Temperature Combustion by Optical Diagnostics

Abstract

Optical diagnostics is an effective method to understand the physical and chemical reaction processes in homogeneous charge compression ignition (HCCI) and low temperature combustion (LTC) modes. Based on optical diagnostics, the true process on mixing, combustion, and emissions can be seen directly. In this paper, the mixing process by port-injection and direct-injection are reviewed firstly. Then, the combustion chemical reaction mechanism is reviewed based on chemiluminescence, natural-luminosity, and laser diagnostics. After, the evolution of pollutant emissions measured by different laser diagnostic methods is reviewed and the measured species including NO, soot, UHC, and CO. Finally, a summary and the future directions on HCCI and LTC used optical diagnostics are presented.

Influence of the number of injections on piston heat rejection under low temperature combustion conditions in an optical compression-ignition engine

“…The in-cylinder flow structure is also critical for PPC because of its influence on the fuel-air mixing process [21]. These patterns of incylinder gas movement can be studied by means of optically accessible engines [22] [23]. An outstanding technique to conduct this kind of research is particle image velocimetry (PIV) [24].…”

Overview of Clean Automotive Thermal Propulsion Options for India to 2030

“…This process reduces high flame fronts and maintains the in-cylinder temperatures at lower levels. In a study of HCCI and low temperature combustion with the aid of optics [40], it was demonstrated that near-zero NOx emissions were feasible due to low combustion temperature and high EGR attenuation. The overall homogenous lean air-fuel mixture also tends in avoiding the soot formation in emissions.…”