Coated Piston Ring Thermal Resistance for Blow-By Reduction
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Solution Overview
Problem
Piston rings made of chromium-based stainless steel can experience an increase in blow-by gas even without heat deformation, posing a challenge in reducing emissions and improving fuel efficiency.
Innovation Solution
A piston ring with a coating having a thermal resistance value of 2.0×10−6 to 12.0×10−6 m2·K/W, which effectively reduces blow-by gas by controlling thermal expansion and preventing heat deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If chromium-based stainless steel is used for the piston ring, then heat resistance is improved, but blow-by gas increases
Solution Approach 1:
The patent applies composite materials by combining chromium-based stainless steel base material with a specifically designed coating layer. The coating has controlled thickness (0.5-5.0 μm) and composition to achieve optimal thermal resistance, creating a composite structure that resolves the contradiction between heat resistance and blow-by gas reduction.
Solution Approach 2:
The patent changes physical parameters by precisely controlling the coating thickness within 0.5-5.0 μm and adjusting the thermal resistance value to 0.5×10−6 to 5.0×10−6 m2·K/W. These parameter optimizations enable the piston ring to maintain appropriate temperature for sealing while preventing excessive heat accumulation that causes blow-by gas.
2Temperature
If coating thickness is increased, then thermal resistance is improved, but heat deformation is suppressed
Solution Approach 1:
The patent optimizes the coating thickness parameter within the range of 0.5-5.0 μm and thermal resistance within 0.5×10−6 to 5.0×10−6 m2·K/W. This precise parameter control achieves the balance between providing sufficient thermal resistance to reduce blow-by gas and preventing excessive heat accumulation that would cause heat deformation.
Solution Approach 2:
The coating is applied specifically to the outer peripheral surface of the piston ring where thermal management is most critical. This localized treatment provides the necessary thermal resistance at the contact surface with the cylinder liner while maintaining the overall structural integrity and heat dissipation pathways of the piston ring.
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
The piston ring design significantly reduces blow-by gas emissions and improves fuel consumption by optimizing thermal resistance and adhesion properties of the coating.
Implementation Method 1
the thermal resistance value of the coating correlates with the fuel consumption and the blow-by gas... the thermal resistance value is a value represented by the following Formula 1
Implementation Method 2
the temperature of the piston ring rises with the operation of an engine, and accordingly, the piston ring moderately expands to narrow a gap at the joint portion of the piston ring
Data Source
AI summary
A piston ring including: a piston ring base material having a joint portion; and a coating covering at least an outer peripheral surface of the piston ring base material, the coating having a thermal resistance value of 2.0×10−6 to 12.0×10−6 m2·K/W.