Can a seat be fuel efficient?

Did you know that it is not stated explicitly in the Shell Eco-Marathon rules that a seat is required? If you don’t trust us you can always read the rules for yourself here. Even if it is not stated in the rules that a car requires a seat, we all know that a seat is an important part of the car, with respect to both safety and comfort.

With a well-developed seat DNV GL Fuel Fighter will be closer to winning the technical innovation award, design award and most importantly the safety award. The technical innovation award is a possible award to win by showing ingenuity in the choice of materials for the seat. For the design award we are designing a seat that is comfortable, that fits the overall theme of the car, and with a design that is pleasant and aesthetic.

For the safety award it is important that the position of the driver allows for easy access and exit of the vehicle in case of fire. It is vital that the seat supports the driver in a way that reduces injuries in case of impact. It is also important that the driver has the best possible overview. This is further specified in the SEM rules article 28-33.

Here is a sneak peak of the Shell Eco-Marathon rules.

The Design Team had three main concerns while designing and manufacturing the seat. The seat had to be light to minimize the impact on fuel efficiency, it had to be beautiful and aesthetic and last but not least it had to bring safety and comfort to the driver. We also wanted to cut down on the manufacturing costs and decided to make the seat at the University, NTNU, instead of in Fredrikstad where the monocoque mold was created. This meant that they had to manufacture everything by them self. Everything from milling the molds for the seat to grinding the finished seat had to be done by the design group.

This is how the seat was made. The white layer is the gypsum, which is the first layer of the sandwich.

There are however some drawbacks to using such a cheap material. A major problem is that the surface of the foam was not suitable in it self as a base for the carbon fiber layup. In order to reduce the roughness, it was decided to create an entirely new surface made out of layers of gypsum, gelcoat and PU paint. With a new smooth surface we were able to lay up the carbon fiber sandwich with a really nice glossy finish. But most important of all was of course our secret ingredient, tons of love.

As with the monocoque, the combination of different kinds of materials, like foam and carbon fiber, gives the seat a lighter weight with the added benefit of a strong and flexible composite material. In addition, the extra volume from the foam core allows the group to create a more voluminous seat with more dimension.

The seat will be separated into two parts: one part that consist of the back and one part that consist of the actual seat/bottom. There are several reasons for this. Firstly, it makes it possible to adjust the back and bottom independently of each other. This is important if we are to use the seat for another year with a different driver. Secondly, it removes some excess weight from the seat. One of the challenges in creating the seat is that the driver has to be seated in a little bump underneath the car where the seat had to be super thin. Instead it was decided it was easier to just cut out that section of the seat. Third, but probably most important of all, it fits our design goal of a seat that “glides” seamlessly into to the driver’s compartment.

At the moment of writing the seat is in production. The “sandwich” that will become the seat is placed on top of the mold. When the molding process is done all we need to do is remove the newly made seat from the mold, grind away the epoxy and then install the seat into the car.

Here is the two separate parts of the seat.