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- Design and Fabrication of a small SI Two-Stroke Engine Murphy 1.0Publication . Rocha, José António Pacheco Nunes da; Brojo, Francisco Miguel Ribeiro ProençaInternal combustion engines (ICEs) perform an important role in today’s society and will keep doing so in the foreseeable future. Even with all the technological development regarding electric motors, there is still a long way to go before they can substitute ICEs, if they ever do. It is therefore important that the development of ICEs continues, otherwise, the potential further advantages that ICEs can offer will not be realized. This dissertation was done to assess the possibility of designing and fabricating a two-stroke engine cylinder and cylinder head in the university. This work will then consist of a conceptual project regarding the design and fabrication of a piston-ported two-stroke SI engine cylinder and cylinder head. As engines typically have some sort of name/reference, the prototype designed was named “Murphy 1.0”. Firstly, a theoretical study about internal combustion engines, more specifically two-strokes SI engines, was done and then with the information gathered, a prototype was drawn in CATIA V5. To fabricate the “Murphy 1.0” prototype it was established a fabrication process that can be achieved at the university to obtain cast-pieces with considerable accuracy and detail. All the practical components necessary for the fabrication and for the start up of the engine were also made at the university and will be presented throughout this document. Several adversities were faced in the experimental component and the major ones will be presented in this document. For instance, the design was made idealizing the usage of a carburetor and a CDI ignition system for small engines but due to experimental problems, both had to be changed. It was then done the wiring harness to an ECU (Microsquirt V2) and afterward, the required sensors/actuators were installed to both the ECU and to the engine to permit the electronical control of the ignition and fuel injection. Unfortunately, it was not possible to get “Murphy 1.0” to start up. The possible reasons for such will be presented and explained in the final chapters but the reason that was most likely impeding the prototype from working was the lack of compression in the cylinder. This lack of compression was prevenient from a leak in the cylinder head gasket. Due to the deadline set for this dissertation, it was not possible to find a solution to fix this in time. The attempts made to solve this problem in the available time will also be explained at the end of this document. Without first solving the problem regarding compression, the methodology followed to design the ports cannot be properly assessed. It was therefore not conclusive if the designed engine could or could not work. Throughout this document, all the choices and steps made will be explained, not only regarding the engine design but also the fabrication methods used so that a replication, or an adaption, of this work can be made.