Fuel efficient vehicle design

The shell eco marathon was the first long term project that I worked on during my bachelors in 2014 and 2015. The aim of the project was to design and build a fuel efficient vehicle with the goal of minimizing fuel consumption. As team leader and project manager, not only was I responsible for the technical execution of the project but also the overall project management. Through the project I learn’t what it meant to work with team members of different backgrounds, skills and motivations and to deliver a project on time. I was personally responsible for the design of the chassis, drivetrain, wheels, braking system, procurement and all manufacturing.

Chassis 1 - Welded aluminium frame with carbon fibre shell

For our first competition, I designed a welded aluminum chassis using hollow rectangular sections. Given the vehicle’s low speeds and consequently low dynamic loads, the primary design focus was on ensuring the chassis could resist static bending loads (due to weight) and dynamic twisting loads during cornering and braking. Rectangular aluminum profiles were selected for their high moment of inertia in the bending plane, as well as aluminum’s excellent strength-to-weight ratio, making them ideal for large frame structures. Additionally, the flat surfaces of the rectangular sections, compared to circular ones, simplified the mounting of other components onto the chassis.

Chassis 2 - Carbon fibre monocoque

With our constant drive to achieve a lightweight design, for the second year I designed a fully carbon fibre monocoque chassis. The sandwich sheets used for the monocoque structure were fabricated using a honeycomb (NOMEX) core sandwiched between layers of carbon fibre on both sides, to create a lightweight yet stiff structure.

Pottet inserts were embedded within the sandwich structure for attaching the front wheel suspensions, belt attachment points and the engine mounts.

The design and analysis of the chassis was also the topic of my bachelor thesis, which can be read here (Insert link).

Drivetrain

• For the drivetrain design, the key idea was the create a transmission from the engine output shaft to the wheels in such a way that the max constant speed of the car would make the engine run at its most efficient speed (seen in the power vs rpm curve from manufacturer)
• A Hatz diesel engine from locally available earth compactors was chosen

Project Management

Use of excel gannt charts and work packages to do the long term project management and Trello to carry out the daily project management in an agile manner with the other team mates

Challenges faced during the project

• Being our first large scale engineering project, it was a far from perfect run, filled with problems and time mismanagement