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Intake Port Isolation for Direct Injected Turbo Charged Gasoline Engines

Emil Håkansson
Göteborg : Chalmers tekniska högskola, 2011. Diploma work - Department of Applied Mechanics, Chalmers University of Technology, Göteborg, Sweden, ISSN 1652-8557; 2011:16 , 2011.
[Examensarbete på avancerad nivå]

This thesis work relates to an intended improvement of volumetric efficiency, particularly on lower engine speeds, in a direct injection turbo charged gasoline engine. It has been known for a long period of time that heat transfer rate in flow components, such as intake system can have considerable effects on mass flow and consequently volumetric efficiency. There are several ways to enhance the amount of air flowing thru an engine, such as increasing size of intake and exhaust geometries. The modification that will be implemented in this project is not supposed to increase the volume of air that will flow thru the engine, but to a certain extent increase the mass flow of it. This is achieved by decreased intake air temperature which results in increased density and hence increased mass flow of the incoming intake air charge. The area of investigation in this thesis project relates to the fact that heat builds up in the cylinder head and transfers to the intake ports surfaces making them very hot. The main objective is to study how a decreased temperature of the intake ports surfaces influences the temperature of the incoming intake air. To efficiently accomplish such a study, a technical solution which intends to reduce heat transfer to the intake ports surfaces must be developed and isolated intake ports are one example of such a solution. The expected outcome of this solution is that the surface temperatures in the intake ports will be reduced and consequently heat transfer to the incoming intake air charge is reduced to a certain extent. The primary aim of the thesis project is to develop a technical solution that with a great amount prevent heat from transferring to the intake ports surfaces. The secondary aim of this study is to investigate how decreased surface temperature in the intake ports influences the incoming intake air charge temperature. Finally, the results will be compared against measured data, obtained from an identical standard single cylinder head. The intention of reducing the surface temperature in the intake ports is to hopefully answer some questions such as were the highest amount of heat transfer occurs in the intake port, if it mostly occurs over the entire intake port or predominantly near the hot intake valves. The results from the GT-Power engine simulations showed that isolated intake ports obtained a reduced surface temperature in the intake ports. That substantially led to a decreased temperature of the incoming intake air, particularly on lower engine speeds. In the single cylinder experiments it was found that the isolated intake ports were a possible method to reduce the temperature of the incoming intake air. Thus, the result did not become as positive as was indicated from the results of the theoretical simulations. To conclude, the major drawback was experienced during experiment testing, there it was noticed that the standard intake ports did not heat the incoming intake air as much as was expected. This consequently resulted that the initial improvement potential of isolated intake ports influence on intake air was not as great as what is expected from the beginning of the thesis.



Publikationen registrerades 2012-01-13. Den ändrades senast 2013-04-04

CPL ID: 152880

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