Cylinder Surface Roughening for Thermal Coating Porosity
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing thermal coating methods for cylinder running surfaces in internal combustion engines struggle to maintain consistent oil retention volume due to varying porosities, which can lead to a collapsing oil film at high thermal and mechanical loads, especially at piston reversal points.
Innovation Solution
Introducing different roughening profiles during the surface preparation process allows for varying coating properties, such as porosity, to be achieved with constant spraying parameters, by modifying the microstructure of the surface without altering the spraying parameters, thereby ensuring higher oil retention volumes at specific locations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If different porosities are created by varying spraying parameters during thermal spraying, then oil retention volume is improved at different cylinder locations, but device complexity increases due to dynamic parameter adjustment requirements
Solution Approach 1:
The patent applies local quality by creating different roughening profiles (first and second profiles with different arithmetic mean roughness values) at different locations along the cylinder running surface. This allows the surface to have location-specific properties that dictate coating porosity and oil retention characteristics, eliminating the need for dynamic spraying parameter adjustments while achieving the same functional result.
Solution Approach 2:
The patent implements preliminary action by pre-roughening the cylinder running surface with specific profiles before applying the thermal coating. The roughening process creates predetermined surface structures that will subsequently influence coating formation and porosity distribution, allowing the coating process to proceed with constant parameters while still achieving variable porosity outcomes.
2Reliability
If spraying parameters are dynamically adjusted during thermal spraying, then coating porosity is optimized at different positions, but manufacturing precision decreases due to parameter variation
Solution Approach 1:
The patent performs the roughening operation before coating application, creating predetermined surface profiles that will control coating porosity. This preliminary action allows the subsequent coating process to use constant, precise spraying parameters while still achieving variable porosity through the interaction between the thermal spray material and the pre-formed roughening profiles.
Solution Approach 2:
By creating location-specific roughening profiles with different arithmetic mean roughness values, the patent ensures that each region of the cylinder surface has the precise surface characteristics needed for its specific operational requirements, while the coating process itself maintains consistent, high-precision parameters throughout.
3Device complexity
If constant spraying parameters are used during thermal coating, then device complexity is reduced, but coating porosity uniformity worsens across the cylinder surface
Solution Approach 1:
The patent resolves this contradiction by making the substrate (cylinder running surface) non-uniform through different roughening profiles rather than making the coating process non-uniform. The first and second roughening profiles with different arithmetic mean roughness values interact with the constant-parameter thermal spray to produce location-specific coating porosity, achieving functional variation without process complexity.
Solution Approach 2:
The roughening profile acts as an intermediary between the constant-parameter coating process and the desired variable porosity outcome. The pre-formed surface structures mediate the coating formation process, causing the thermal spray material to deposit with different porosity characteristics in different regions despite uniform spraying parameters.
4Reliability
If the roughening profile is modified with peaks or deformations, then layer porosity and oil retention volume increase, but manufacturing complexity of the roughening process increases
Solution Approach 1:
The patent applies local quality by introducing peaks or deformations only in specific regions of the roughening profile where higher oil retention is needed, rather than uniformly across the entire surface. This allows targeted modification of the roughening process to create local variations in arithmetic mean roughness that drive coating porosity and oil retention characteristics.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method enables the production of desired porosity distributions along the cylinder running surface without changing the coating process, enhancing oil retention and tribological properties, particularly at critical piston positions, while maintaining consistent spraying parameters.
Implementation Method 1
a coating is applied by means of a thermal spraying process
Implementation Method 2
Points and/or deformations are used to introduce targeted points at which oxides, for example, grow preferentially
Data Source
Figure 1~2d
Figure 3~4d
AI summary
The invention relates to a method for roughening and thermally coating a surface (1), especially a cylinder running surface of an internal combustion engine, the roughening being the preparation of the surface (1) for thermally coating the surface (1) with a coating (9). The method is characterised in that, during the roughening process, different roughening profiles are created on the surface (1), and the coating (9) has different properties distributed over the surface (1). In this way, in subsequent thermal coating processes, the coating or spray method can be carried out with essentially constant spray parameters. The different properties of the coating (9), such as hardness, porosity, machinability, chemical composition, oxidation and adhesion are generated just by each different roughening of the surface (1).