Heat losses in internal combustion engines

 

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dc.contributor.advisor Priede, T en_ZA
dc.contributor.author Clarke, Ralph Henry en_ZA
dc.date.accessioned 2014-10-11T11:53:59Z
dc.date.available 2014-10-11T11:53:59Z
dc.date.issued 1989 en_ZA
dc.identifier.citation Clarke, R. 1989. Heat losses in internal combustion engines. University of Cape Town. en_ZA
dc.identifier.uri http://hdl.handle.net/11427/8290
dc.description Bibliography: leaves 119-121. en_ZA
dc.description.abstract This thesis deals with the effects of cooling and heat losses in internal combustion engines. The object of this work was to examine and research various cooling concepts and methods to reduce heat loss to engine coolant, improve thermal efficiency and to predict heat transfer values for these alternatives. The optimum system to be considered for possible application to small rural stationary engines. A literature survey was undertaken, covering work performed in the field of internal combustion engine cooling. Besides the conventional cooling system, two concepts emerged for consideration. These were the precision cooling system and the new heat pipe concept, the latter being relatively unknown for internal combustion cooling application. The precision cooling system, consists of a series of small bore tubes conducting coolant only to the critical areas of an engine. The theory being that in the conventional systems many regions are overcooled, resulting in excessive heat loss. The heat pipe is a device of very high thermal conductance and normally consists of a sealed tube containing a small quantity of fluid. Under operating conditions the tubular container becomes an evaporator region in the heat input area and a condenser region in the heat-out area. It is therefore basically a thermal flux transformer,attached to the object to be cooled. The heat pipe performance is also capable of being modulated by varying its system pressure. This is a positive feature for internal combustion engine application in controlling detonation and NOx emissions. Various facts were obtained from the literature survey and considered in the theoretical review. These facts were extended into models, predicting the heat transfer performance of each concept in terms of coolant heat outflow and heat transfer coefficients. The experimental apparatus was based on an automotive cylinder head with heated oil passing through the combustion chamber and exhaust port to simulate combustion gases. Experiments were conducted on this apparatus to validate the predicted theoretical performance of the three concepts. Tests were also made to observe the effect of heat pipe modulation and nucleate boiling in the precision system. Concept theory was validated as shown by the experimental and test results. The performance for each system approximated the predicted heat transfer and heat loss values. By comparison of the heat input, coolant heat outflow values and heat transfer coefficients it was found that the precision system was the most efficient, followed by the heat pipe and the conventional system being the least efficient. It was concluded that the heat loss tests provided a valuable insight into the heat transfer phenomenon as applied to the three systems investigated. This work also illustrated the effects of the variation of coolant flow, velocity and influence of nucleate boiling. This thesis has shown the potential of the systems tested, for controlling heat losses in internal combustion engines. The research work has created a data base for further in-depth evaluation and development of the heat pipe and the precision cooling system. Based on the findings of the experimental work done on this project, several commercial applications exist for the heat pipe and precision cooling systems. Further in-depth research is recommended to extend their potential in the automotive industry. en_ZA
dc.subject.other Energy and Development Studies en_ZA
dc.title Heat losses in internal combustion engines en_ZA
dc.type Thesis / Dissertation en_ZA
uct.type.publication Research en_ZA
uct.type.resource Thesis en_ZA
dc.publisher.institution University of Cape Town
dc.publisher.faculty Faculty of Engineering & the Built Environment en_ZA
dc.publisher.department Energy Research Centre en_ZA
dc.type.qualificationlevel Masters en_ZA
dc.type.qualificationname MSc en_ZA
uct.type.filetype Text
uct.type.filetype Image


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