Pilot study describing the design process of an oil sump for a competition vehicle by combining additive manufacturing and carbon fibre layers

Abstract

Formula Student is an international competition governed by the Society of Automotive Engineers (SAE) which challenges university students to design and build a racing car that will subsequently be compared against other cars from universities around the world on homologated racing circuits by non-professional drivers. This study focuses on the design, analysis and manufacturing process of a new oil sump for a Formula Student car - which involves combining a main ABS-plastic core created by an additive manufacturing (AM) printing process and a manual lay-up process with carbon fibre - in order to reduce the sloshing effect due to the movement of the oil during racing. The new oil sump and the original sump were modelled with computer-aided design (CAD) software and five computational fluid dynamics (CFD) simulations were performed to compare the sloshing effect in both designs in three driving scenarios: acceleration, braking and changing direction. The simulations showed that acceleration is not a critical situation since the new internal design of the sump was capable of delaying the immersion time of the oil pick-up pipe from 0.75 seconds to 2 seconds during braking and from 0.4 seconds to 0.8 seconds during lateral acceleration. The new design was physically manufactured and subsequently integrated into an internal combustion engine for testing for 45 minutes. During this test, the engine was started and put at 9600 RPM, so the oil worked under realistic temperature conditions (80 degrees C). It did not present any oil leak. After testing, it was disassembled and visually inspected. No failure in the inner surfaces of the oil sump was observed due to temperature. According to these results, the present research argues that the combination of AM technology (i.e., fused deposition modelling) and layers of carbon fibre is a real alternative to conventional manufacturing processes in order to create geometrically complex oil sumps that minimise the sloshing effect in competition automobiles.