Životnost tepelných výměníků z Al slitin v prostředí kondenzátů spalin výfukových plynů

Abstract

This dissertation entitled The Durability of Aluminum Heat Exchangers Exposed to Exhaust Gas Condensates provides a comprehensive analysis of the issues encountered by aluminum alloys exposed to exhaust gasses containing corrosive constituents. The introduction addresses the challenges encountered in developing modern forced induction (turbocharged and supercharged) internal combustion engines required to meet stringent vehicle emission requirements. These emission standards have led to the need to introduce exhaust gasses into the air intake to improve efficiency of forced induction systems. These exhaust gasses can form acidic substances that contact components, such as charge air coolers, which have not previously seen this type of corrosive environment. A subsequent portion of the dissertation is devoted to a detailed description of automotive charge air cooler heat exchangers and their production which can significantly affect the corrosion resistance of the aluminum materials used in their fabrication. This dissertation contains a principled description of corrosion followed by a focused study of internal corrosion experienced in heat exchangers. The challenges presented by this this issue require a unique approach when evaluating the corrosion resistance of the aluminum materials used to manufacture heat exchangers. The experimental portion of this work describes a method suitable for the basic selection of materials resistant to the corrosive environment experienced on the inside surface of a charge air cooler due to the presence of condensing exhaust gasses introduced during exhaust gas recirculation. The experimental phase of this work includes: the selection of a model test media (simulated condensate product), the development of a corrosion test procedure, and the generation of aluminum corrosion test results. Conclusion based on the interpretation of the corrosion test results as well as recommendations for future actions are also presented.