A Review of Coating Methods and Their Applications in Compression and Spark-Ignition Engines for Enhanced Performance

Coating of metallic surfaces such as cylinder heads, cylinder liners, piston heads and exhaust-valves in Internal Combustion Engines (ICEs) has improved engine performance in areas of brake-thermal-efficiency including brake-specific-fuel consumption, etc. This review showed different methods of coating in compression and spark-ignition engines for improved performance using different coating thicknesses on the metallic surfaces. These coating thicknesses may be either minimum or maximum depending on the coating method used. The coating methods discussed in this paper were Thermal Spraying (TS), Physical-Vapour Deposition (PVD), Chemical-Vapour Deposition (CVD) and Ion Implantation methods. Minimum thicknesses were achieved using the PVD, CVD and Ion-Implantation methods. In addition, Sol-Gel and Slurry coatings were also discussed. Having considered these methods of coating, thermal-spraying method was recommended for compression and spark-ignition engines because it produces temperature ranging from 8000 K-14000 K on surfaces with thick coating thicknesses.