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2021
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Three major processes of plasma thermal spraying of cylinder bores
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As governments around the world continue to raise regulations on vehicle emissions and fuel consumption, new requirements have been put forward for engine weight reduction and friction reduction.
As governments around the world continue to raise regulations on vehicle emissions and fuel consumption, new requirements have been put forward for engine weight reduction and friction reduction.
In order to meet the new requirements for emissions and fuel consumption of fuel vehicles, the powertrain needs to improve driving efficiency, reduce friction, reduce weight, and reduce oil consumption. More and more automobile OEMs are researching and developing the process of spraying coating on the inner wall of the cylinder bore of aluminum alloy cylinder block to replace the traditional cast iron cylinder liner.
By adopting the plasma spraying process for the cylinder bore wall, an all-aluminum alloy cylinder block without a cylinder liner is manufactured to achieve engine lightweighting, reduce engine friction loss, improve engine efficiency, optimize the thermodynamic characteristics of the cylinder bore, etc., and it has become the choice of major foreign automobile companies.
Atmospheric plasma thermal spraying process principle
The cylinder bore coating is honed to form an open and dispersed porous surface. It is these gentle, rounded holes that reduce the exposed area of the fuel in the combustion chamber and piston rings; at the same time, they reduce the tangential force of the oil scraper ring, allowing the piston ring to enter the fluid dynamics state more smoothly, significantly reducing friction. resistance and wear, thereby further reducing fuel consumption and the possibility of blow-by.
The special porous surface oil storage structure will not be worn away during the honing process like the mesh structure of the flat top honing process. As the coating thickness gradually decreases with wear, new lubrication holes will appear on the coating surface, ensuring the sustainability of performance.
In addition, the coating thickness after honing is between 120-150 microns. Compared with cast iron cylinder liners, the thin-wall coating greatly improves the heat conduction between the cylinder bore and the cylinder block.
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