Ett designprojekt för cylinder, vevhus och vevparti till en förbänningsmotor för EcoMarathonfordon Vera III

Abstract

This report describes a bachelor thesis written by three students from the department of Mechanical Engineering at Chalmers University of Technology. The focus of the work has been on developing a complete bottom end consisting of crankset and crankcase for a single-cylinder four-stroke engine operating on otto principle. The study has been conducted in collaboration with another group writing their bachelor thesis on the cylinder head of the same engine. The common goal has been to provide drawing and design documentation for a fuel efficient engine. The work was initiated with a extensive pilot study in which information on commercially available engines, various engine designs and previous engines designed for Chalmers Vera Team was compiled and analyzed. This, along with the regulations for the Eco-Marathon competition, became the basis on which the rest of the work was based on. The work resulted in a 51cc engine with a long stroke and small cylinder diameter. This is because the engine has been optimized against fuel efficiency. The newly designed bottom end includes crankcase and cylinder with connecting rod and crankshaft. Due to the time limit set for the project of 15 credits, 400 hours per group member, the work was limited to a design phase and a 3D printed model of the bottom end and together with the cylinder head designed by the other group, would be assembled together into a complete model of the engine. After the completion of the project, the drawings of the engine mk VIII will be submitted to Chalmers Vera Team for manufacturing.