NH-DLC Coating for Ethanol Fuel Injector Corrosion

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Solution Overview

Problem

Vehicle components that contact ethanol-blended fuels are prone to thermal and corrosive damage due to the corrosive properties of ethanol and elevated temperatures, leading to issues such as corrosion and wear, which affect the efficiency and reliability of fuel delivery systems.

Innovation Solution

A layer of non-hydrogenated diamond-like carbon (NH-DLC) material with a high carbon content and specific sp3 and sp2 hybrid bond ratios is applied to vehicle components, providing a protective coating that is inert to thermal and corrosive damage, and is deposited using methods like filtered cathodic vacuum arc or plasma enhanced chemical vapor deposition.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional fuel delivery components are used, then the system is simple and cost-effective, but the components suffer from corrosion and thermal damage when exposed to ethanol-blended fuels

Engineering Contradiction:

Improvecorrosion resistanceVSAvoidcoating application complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies a composite coating system consisting of multiple layers: an etch primer layer for surface preparation, a corrosion inhibitor layer containing phosphates and silicates, and a topcoat layer providing thermal and chemical resistance. This multi-layer composite structure addresses the corrosion and thermal damage issues while maintaining system reliability.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent modifies the chemical composition parameters of the coating layers to achieve optimal protection. Specifically, the corrosion inhibitor layer contains 5-20 weight% phosphates and 5-20 weight% silicates, while the topcoat layer has specific ratios of silica, alumina, and zirconia. These parameter adjustments enable the coating to resist ethanol-blended fuel corrosion effectively.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If the NH-DLC coating is applied, then corrosion and wear protection is improved, but the manufacturing process becomes more complex

Engineering Contradiction:

ImprovedurabilityVSAvoidcoating deposition ease

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent replaces conventional mechanical coating methods with physical vapor deposition (PVD) techniques, specifically filtered cathodic vacuum arc (FCVA) or plasma-enhanced chemical vapor deposition (PECVD). This substitution enables precise control of coating composition and structure, achieving high sp3 carbon content (60-100%) and controlled sp2 content (0-40%), which provides superior durability while managing manufacturing complexity through automated deposition processes.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 NH-DLC coating effectively protects vehicle components from corrosion and wear, improving their durability and reducing emissions by preventing fuel leaks, while maintaining thermal stability and chemical inertness against ethanol-blended fuels and additives.

Implementation Method 1

The NH-DLC material has a carbon content of greater than or equal to about 90 atomic % (at. %), a carbon-carbon sp3 hybrid bond content of from greater than or equal to about 60% to less than or equal to about 100%, and a carbon-carbon sp2 hybrid bond content of from greater than or equal to about 0 to less than or equal to about 40%.

Methodology Applied

Scientific EffectChemical inertness:

Implementation Method 2

Methodology Applied

Scientific EffectThermal stability:

Implementation Method 3

deposited using methods like filtered cathodic vacuum arc or plasma enhanced chemical vapor deposition

Methodology Applied

Scientific EffectVacuum arc deposition: Cathodic Arc Deposition

Implementation Method 4

deposited using methods like filtered cathodic vacuum arc or plasma enhanced chemical vapor deposition

Methodology Applied

Scientific EffectPlasma enhanced chemical vapor deposition: Plasma Enhanced Chemical Vapour Deposition

Data Source

PatentUS10247157B2Diamond like carbon (DLC) coating for ethanol-blended fuel injector applications

Publication Date: 2019.04.02 GM GLOBAL TECHNOLOGY OPERATIONS LLC

AI summary

A vehicle part or component includes a surface that is configured to contact a fuel containing ethanol. The surface has a layer of non-hydrogenated diamond like carbon (NH-DLC) material disposed on the surface. The layer of NH-DLC has a thickness of from greater than or equal to about 100 nm to less than or equal to about 100 μm. The NH-DLC material has a carbon content of greater than or equal to about 90 atomic % (at. %), a carbon-carbon sp3 hybrid bond content of from greater than or equal to about 60% to less than or equal to about 100%, and a carbon-carbon sp2 hybrid bond content of from greater than or equal to about 0 to less than or equal to about 40%. The NH-DLC material is substantially free of hydrogen atoms. Methods for manufacturing the vehicle part or component are also provided.