This Master’s thesis discusses the investigation of autoignition (knock) of air-fuel mixtures in internal combustion engines (type EA 827; 1.6 and 1.4 l) under hot start conditions. Chapter Three comprehensively reviews literature on fuel characteristics; specifically boiling point, chemistry and the difference between the Research and Motor Octane Number (RON and MON). Furthermore different types of autoignition are discussed with regards to their detection and assessment in the chapter. The subsection on engine management looks at possible methods of altering and eliminating autoignition. Chapter Four details the equipment used to obtain data and measurements, as well as the signal conditioning of the spark and injector signal. Chapter Five discusses the actual results obtained during summer testing of the different methods of altering and eliminating autoignition in an internal combustion engine, as derived from the theories presented in Chapter Three. The summer tests finally verified the new application level and showed that only a reduction in the quantity of fuel injected can eliminate autoignition. However, a slight decrease in heat release does cause an increase in start time. In Chapter Six, based on the test results, a simulation model which calculates the probability of autoignition in a 1.4 l (Econo) engine during hot start conditions in Matlab/Simulink was developed. This simulation model satisfactorily verified test results.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:nmmu/vital:9621 |
| Date | January 2009 |
| Creators | Wodausch, Jens |
| Publisher | Nelson Mandela Metropolitan University, Faculty of Engineering, the Built Environment and Information Technology |
| Source Sets | South African National ETD Portal |
| Language | English |
| Detected Language | English |
| Type | Thesis, Masters, MTech |
| Format | xvi, 158 leaves, pdf |
| Rights | Nelson Mandela Metropolitan University |
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