Elongated Mounting Holes in Charge Air Cooler Headers
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Solution Overview
Problem
Conventional main headers in internal combustion engine charge air coolers suffer from poor brazing strength and leakage due to limited surface area contact between the main header and aluminum tubes, leading to issues like solder cracking and peeling, especially under bumpy road conditions.
Innovation Solution
The punctured type main header features elongated mounting holes formed through a die stretching process, with a first feature layer containing gas bubbles and a high-performance ceramic material layer produced from Y2O3, Al2O3, and ZrO2 ceramic powders, and a solder coating, providing enhanced brazing strength and sealing performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional main header structure is used, then manufacturing is simple, but brazing strength is poor and leakage occurs
Solution Approach 1:
The mounting holes are transformed from simple circular cross-sections to elongated shapes with increased surface area. This dimensional change in the hole geometry provides greater brazing area between the main header and aluminum tubes, directly improving brazing strength without fundamentally changing the manufacturing process flow.
Solution Approach 2:
The main header is designed with non-uniform mounting hole distributions in different regions. The elongated mounting holes are strategically positioned and sized to provide enhanced brazing strength specifically at locations where thermal and mechanical loads are highest, optimizing the local brazing quality where it is most needed.
2Reliability
If conventional main header structure is used, then manufacturing process is simple, but sealing performance is poor
Solution Approach 1:
The elongated mounting holes increase the contact surface area between the main header and aluminum tubes, creating a more extensive sealing interface. This dimensional change in hole geometry directly improves sealing performance by providing greater area for the solder coating to form reliable seals.
Solution Approach 2:
The main header incorporates a multi-layer coating structure including a first feature layer with gas bubbles and a second feature layer made of high-performance ceramic materials (Y2O3, Al2O3, ZrO2). This composite coating system enhances sealing performance by providing both adhesion and barrier properties at the brazing interface.
3Reliability
If conventional main header structure is used, then manufacturing is straightforward, but solder cracking and peeling occur under bumpy road conditions
Solution Approach 1:
The elongated mounting holes provide increased surface area for solder deposition, creating a more robust brazing joint that can withstand mechanical vibrations and thermal cycling from bumpy road conditions. The extended surface area distributes stress more evenly, reducing the likelihood of solder cracking and peeling.
Solution Approach 2:
The multi-layer coating system with gas bubbles in the first layer and ceramic materials in the second layer creates a graded structure that accommodates thermal expansion differences between the aluminum header and copper tubes. This composite structure prevents solder joint failure under thermal and mechanical stress from road vibrations.
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 improved design significantly increases the brazing area between the main header and aluminum tubes, reducing leakage and enhancing the reliability of the charge air cooler by providing superior brazing strength and minimizing solder peeling.
Implementation Method 1
stretching the plurality of mounting holes by a die stretching process to convert the sidewall into an elongated sidewall
Implementation Method 2
brazing each of the plurality of the mounting holes to an aluminum tube
Data Source
AI summary
The present disclosure generally provides an improved punctured type main header of an internal combustion engine CAC. In one embodiment, the punctured type main header includes a body having multiple mounting holes disposed in the length direction of the main header, wherein each mounting hole has a sidewall. The body includes an aluminum tube coupled to each mounting hole, a first feature layer formed on the sidewall of each mounting hole, wherein the first feature layer has gas bubbles formed therein, a second feature layer formed on the first feature layer, the second feature layer is a high performance material (HPM) produced from raw ceramic powders of Y2O3, Al2O3, and ZrO2, wherein Y2O3 is in a range between about 45 mol. % and about 100 mol. %, ZrO2 is in a range from about 0 mol. % and about 55 mol. %, and Al2O3 is in a range from about 0 mol. % to about 10 mol. %. The body further includes a solder coating formed on the second feature layer.