Laser cleaning of carbonaceous deposits on combustion engine components

Stubborn carbonaceous deposits on combustion engine components are known to reduce engine durability and performance. The deposits are extremely hard and difficult to remove. Laser cleaning technique may potentially be used to remove these deposits during engine remanufacturing but is rarely reported. In the present work, we demon-strated the feasibility of using a nano-second pulse width and high peak power laser with homogenised beam profile at 1064 nm wavelength to completely remove carbon deposits from steel and aluminium pistons. This one-step process without use of chemicals or any other additives is environmentally friendly and may be carried out with high efficiency in open air. Surfaces before and after laser cleaning were examined using FTIR, XPS, and SEM/EDS to identify changes in chemical analysis, morphology as well as microstructure. Cross-sectional examination of the laser cleaned regions was further investigated to reveal any heat affected zone. Some thermal melting and removal of base materials were found to occur but could be minimized with optimized process parameters. Numerical analysis of thermal effect involved in laser cleaning was further carried out by finite element analysis (FEA) using ANSYS.