Piston Top-Land Coating for Minimal Flame-Ring Clearance
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Solution Overview
Problem
The existing piston designs in internal combustion engines suffer from a waste volume between the piston and the flame ring, which reduces engine efficiency due to high manufacturing tolerances required to minimize this clearance, leading to inefficient combustion of fuel mixture.
Innovation Solution
A piston with a soft, non-abrasion-proof coating, preferably resin-bonded graphite, is applied to the top land, allowing local removal during operation to set the necessary clearance between the piston and the flame ring, minimizing waste volume without demanding high manufacturing tolerances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the clearance between piston and flame ring is minimized to reduce waste volume, then engine efficiency is improved, but manufacturing tolerances must be extremely high which increases manufacturing difficulty
Solution Approach 1:
A soft coating is applied to the piston top land before assembly, which will be gradually worn away during initial operation to achieve the target clearance. This preliminary action allows the clearance to be set more loosely during manufacturing, while still achieving the tight final clearance needed for efficiency.
Solution Approach 2:
The soft coating on the piston automatically wears down through normal operation and contact with the flame ring, self-adjusting the clearance to the optimal value without requiring precision manufacturing or external intervention. The system uses its own operating conditions to achieve the desired clearance.
2Loss of energy
If the piston crown is pulled back axially to reduce waste volume, then engine efficiency is improved, but the structural design becomes more complex
Solution Approach 1:
Instead of modifying the entire piston structure by pulling back the crown, only the top land region is coated with a soft material. This localized treatment achieves the waste volume reduction goal while maintaining the standard piston structural design, avoiding increased complexity.
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 solution effectively reduces the waste volume between the piston and the flame ring, enhancing engine efficiency by allowing dynamic adjustment of the clearance during operation, thereby improving combustion efficiency.
Implementation Method 1
the non-abrasion-proof coating consists of resin-bonded graphite... During a local contact of the top land of the piston with the flame ring developing during the operation, the coating can be locally removed
Data Source
AI summary
A piston of a cylinder of an internal combustion engine includes: an upper piston crown; a radially outer surface; a plurality grooves arranged on the radially outer surface; and a plurality of piston rings each positioned in a respective one of the grooves. The radially outer surface forms a top land arranged between the upper piston crown and an uppermost one of the grooves of the piston, and the top land has an axial length and a non-abrasion-proof coating.