Composite Piston Pin Surface Treatment for Friction Reduction
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Solution Overview
Problem
Existing steel piston pins are heavy, lack flexural strength, and do not improve fuel efficiency, necessitating a lightweight composite piston pin with enhanced surface roughness and coating treatment to reduce friction.
Innovation Solution
A method involving a composite piston pin with a surface layer of reinforcing fibers and resin, processed to improve roughness through grinding and polishing, followed by a coating layer comprising a bonding layer of Cr or Ti, a support layer of CrN or WC, and a functional layer of (SiO)-diamond like carbon (DLC), applied at 100 to 240° C to reduce friction coefficient.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a steel piston pin is used, then the piston pin has high strength, but the weight is heavy and fuel efficiency is not improved
Solution Approach 1:
The piston pin is constructed using composite materials consisting of a base material (aluminum alloy or magnesium alloy) and reinforcing fibers (carbon fibers, glass fibers, or aramid fibers). This composite structure provides high strength-to-weight ratio, achieving both the required flexural strength and reduced weight for improved fuel efficiency.
2Object-affected harmful factors
If the surface roughness is improved through grinding and polishing, then the friction is reduced, but the manufacturing complexity increases
Solution Approach 1:
Surface preparation steps including grinding and polishing are performed before coating application to ensure proper adhesion of the low-friction coating. The surface is ground to remove defects and polished to achieve a specific roughness range (Ra 0.1-0.8 μm) that optimizes coating bonding and subsequent friction reduction.
Solution Approach 2:
The surface roughness parameter is precisely controlled within a specific range (Ra 0.1-0.8 μm) through standardized grinding and polishing processes. This parameter optimization ensures both adequate coating adhesion and minimized friction, balancing manufacturing feasibility with performance requirements.
3Reliability
If a coating layer is applied to reduce friction, then the wear resistance is improved, but the manufacturing time and complexity increase
Solution Approach 1:
A multi-layer coating system is applied where each layer serves a specific function: the first layer (Cr or Ti, 0.5-2.0 μm) provides adhesion to the substrate, the second layer (CrN or WC, 1.0-3.0 μm) provides structural support and hardness, and the third layer ((SiO)2-DLC, 0.5-2.0 μm) provides low friction and wear resistance. This localized functional distribution optimizes wear protection while maintaining manufacturing efficiency.
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 method significantly reduces friction, enhancing fuel efficiency and flexural strength, while improving wear resistance and heat resistance, as demonstrated by reduced friction coefficients and wear occurrence in vehicle engine applications.
Implementation Method 1
a first coating step of depositing a bonding layer made of Cr or Ti on the surface layer
Implementation Method 2
a second coating step of depositing a support layer made of CrN or WC on the bonding layer
Implementation Method 3
a third coating step of depositing a functional layer made of (SiO)-diamond like carbon (DLC) on the support layer
Data Source
AI summary
Disclosed herein is a method of treating a composite piston pin, including: preparing the piston pin of which at least surface layer includes a composite material including a reinforcing fiber and a resin; improving roughness by processing the surface layer of the piston pin; and forming a coating layer on the surface layer processed to reduce a friction coefficient of the piston pin.