H11/H13 Piston Crown Cladding for High-Temperature Oxidation Resistance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Pistons for higher power density applications face challenges with insufficient high temperature strength and oxidation resistance, leading to oil deposits in cooling galleries that reduce cooling effectiveness and risk thermal failure.
Innovation Solution
The use of steel H11 and/or H13 alloys for the piston crown and/or skirt, applied through coatings, overlays, or cladding, provides enhanced high temperature oxidation resistance and durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If low alloy steel such as 4140 alloy is used for piston crown, then manufacturing cost is reduced, but high temperature strength and oxidation resistance are insufficient
Solution Approach 1:
The patent applies a steel H11 or H13 alloy coating on top of a low alloy steel substrate (such as 4140 alloy). This composite structure combines the cost advantage of low alloy steel with the high temperature strength and oxidation resistance of H11/H13 alloys, resolving the contradiction between manufacturing cost and high temperature performance.
2Temperature
If cooling oil is circulated in piston cooling gallery, then piston crown temperature is reduced, but oil deposits accumulate and cooling effectiveness diminishes
Solution Approach 1:
The patent changes the chemical composition parameters of the piston crown material by applying H11 or H13 alloy coating, which has different chemical properties than the substrate. This material parameter change reduces oil deposit accumulation and maintains cooling effectiveness over time, while still achieving the desired temperature reduction.
3Reliability
If steel H11 or H13 alloy is used for piston crown, then high temperature oxidation resistance is improved, but material cost increases
Solution Approach 1:
The patent applies H11 or H13 alloy coating only to the piston crown surface where high temperature oxidation resistance is most needed, rather than making the entire piston from expensive H11/H13 alloy. This local application provides the necessary protection at the critical location while minimizing overall material cost.
4Adaptability or versatility
If low alloy steel crown is assembled with micro alloy steel skirt, then manufacturing flexibility is improved, but high temperature strength is insufficient
Solution Approach 1:
The patent creates a composite structure by applying H11 or H13 alloy coating on the low alloy steel crown, maintaining the assembled construction flexibility while upgrading the high temperature strength characteristics through the superior coating material.
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 steel H11 and/or H13 materials enhance piston performance in high power density engines by improving thermal resistance and reducing oil coking, ensuring durability and effective cooling.
Implementation Method 1
The steel H11 alloy includes chromium, molybdenum, vanadium, and iron. The steel H13 alloy includes carbon, chromium, molybdenum, vanadium, iron, and smaller amounts of other alloying elements such as silicon and manganese
Implementation Method 2
Pistons for higher power density applications are often designed with a piston cooling gallery to reduce the piston crown temperatures through forced convection cooling. During operation, cooling oil is contained in or sprayed into the piston cooling gallery to reduce the temperature of the surrounding metal body.
Data Source
Figure 1
Figure 2
AI summary
A piston for an internal combustion engine comprising a piston body having a crown adjacent a skirt. Any of an outer crown surface of the crown, piston ring grooves in the crown, and/or the crown include a steel H11 alloy and/or a steel H13 alloy. The steel H11 or H13 material is applied in any technique such as a piston crown coating/cladding, fused overlay, powder cladding, welded on an outer crown surface of the crown, and/or included in the crown and/or skirt of a monolithic piston. The steel H11 or H13 material is applied with an additive manufacturing item, applied with a coating, buttering, or other surface modification to facilitate joining to the piston body. The application of the steel H11 or H13 material with a heat treatment to at least the piston crown creates an elevated temperature oxidation resistant high performance piston.