Piston Fire Land Coating for Self-Adjusting Flame Ring Clearance

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Solution Overview

Problem

The existing piston designs in internal combustion engines suffer from a harmful volume between the piston and the flame ring, where fuel mixture collection occurs ineffectively, requiring tight manufacturing tolerances to minimize this volume and enhance engine efficiency.

Innovation Solution

A non-abrasion-resistant coating, preferably made of resin-bonded graphite, is applied to the top land of the piston, allowing for local adjustment of the operational clearance between the piston and the flame ring during engine operation by controlled abrasion, reducing the damage volume and increasing efficiency without high manufacturing tolerances.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If the clearance between the piston and flame ring is reduced to minimize dead volume, then engine efficiency is improved, but manufacturing precision requirements increase significantly

Engineering Contradiction:
Improvedead volumeVSAvoidclearance tolerance
Core Design Contradiction:
Loss of energyVSManufacturing precision

Solution Approach 1:

The invention changes the material parameter of the piston top land by applying a soft coating layer, transforming it from a hard, non-compliant surface to a compliant surface that can adapt during operation. This parameter change allows the system to achieve small clearances without requiring extremely tight manufacturing tolerances, as the soft coating compensates for dimensional variations through controlled deformation and wear.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention introduces dynamic adaptability to the clearance system. The soft coating on the piston top land is designed to deform and wear during engine operation, allowing the clearance to self-adjust from an initially larger value to a optimized small value. This dynamic process eliminates the need for static, ultra-precise manufacturing tolerances while achieving the desired minimal dead volume.

Inventive Principle:
Principle #15Dynamics

2Strength

If a hard coating is applied to the top land for durability, then wear resistance is improved, but the ability to adjust clearance through controlled wear is reduced

Engineering Contradiction:
Improvewear resistanceVSAvoidclearance adjustment capability
Core Design Contradiction:
StrengthVSAdaptability or versatility

Solution Approach 1:

The invention applies local quality differentiation by using a soft coating specifically on the piston top land area that contacts the flame ring, while the rest of the piston maintains its original material properties. This localized soft coating provides the necessary compliance for clearance adjustment in the critical contact zone without compromising the overall structural integrity and wear resistance of the piston.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The invention converts the typically harmful effect of wear into a beneficial process. The soft coating is designed to wear controllably during engine operation, and this wear is harnessed to achieve the desired clearance reduction. What would normally be considered damage (wear) is actually the intended mechanism for optimizing the clearance and minimizing dead volume.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

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 non-abrasion-resistant coating effectively minimizes the damage volume and enhances engine efficiency by allowing precise adjustment of the operational clearance between the piston and the flame ring, improving fuel combustion efficiency.

Implementation Method 1

the non-abrasion-resistant coating can be locally removed to precisely adjust the necessary clearance between the piston and flame ring, without requiring high manufacturing tolerances

Methodology Applied
Scientific EffectAbrasion: Abrasion

Data Source

PatentEP3786437B1Combustion engine and piston and cylinder of a combustion engine
Publication Date: 2024.03.13 MAN ENERGY SOLUTION SE
  • EP3786437B1 patent drawingFigure 1
  • EP3786437B1 patent drawingFigure 2

AI summary

Piston (12) of a cylinder (10) of an internal combustion engine, with an upper or front piston head (14) and with a radially outer surface (13), wherein grooves (16a, 16b, 16c) are formed on the radially outer surface (13) in which piston rings (17a, 17b, 17c) are positioned, wherein the radially outer surface (13) forms a fire land (18) between the piston head (14) and the uppermost or foremost groove (16a) of the piston (12), and wherein the fire land (18) bears a non-abrasion-resistant coating (22).