Audi designs its lightest-ever sports prototype

With the R18 e-tron Quattro, Audi has effected multiple optimisation of lightweight design for the 2014 Le Man Prototype (LMP) season.

Since Audi entered LMP racing in 1999, safety rules have never been as strict and a race car as complex as this year. At the same time, the car is allowed to be lighter than ever before.

                                The new rear crash absorbing structure.

The concept design of the new R18 e-tron quattro confronted design engineers at Audi Sport with a particularly challenging requirement. On the one hand, the racing weight of the LMP1 cars compared to last year is allowed to decrease from 915 to 870kg; 45 kilograms less weight make a significant difference in racing. At the same time, the new technical regulations contain various requirements that call for completely new solutions which lead to an increase in weight. For example, to protect the driver in the case of lateral impacts, the regulations prescribe Zylon side panels. The monocoque itself had to be redesigned as well to withstand the higher test loads specified starting in 2014.

The eight wheel tethers (two per wheel) which are to prevent the separation of the wheels from the car in case of a crash are new as well. Furthermore, the 2014 R18 e-tron quattro is equipped with a rear crash absorbing structure. This new component made of carbon fibre reinforced plastic (CFRP) absorbs the energy in a rear-end collision. And, last but not least, the regulations now allow transmissions with seven instead of the previous six forward gears. The new gear pair and its actuation make a difference on the scales as well. “The aggregate of all these measures corresponds to an additional weight of more than 20kg,” explains Dr Martin Mühlmeier, head of technology at Audi Sport. 

                           Not only is CFRP part of lightweight design, metal parts are optimised too

As a result, the engineers were tasked to make the newly designed race car even lighter than before – to compensate for this additional weight while achieving the lower minimum weight. “Thanks to our constant development work there are no measures left that would yield major weight savings in a single step. Instead, the art lies in achieving further improvements of all the details,” says Wolfgang Appel, head of vehicle technology at Audi Sport. Audi has consistently increased the CFRP content in the race car. In the 2014 season, the steering wheel column of the sports prototype is made from this material for the first time. However, this material continues to be prohibited in various areas. For instance, the wheel suspension elements still have to be made of metallic materials, according to the regulations. 

Due to these regulatory specifications and technical options the room for manoeuvre becomes increasingly constrained year after year. In spite of this, Audi achieved its target weight in the R18 e-tron quattro for the current season. The diesel hybrid sports car meets the limit of 870kg.

All in all, Audi says its new R18 e-tron quattro is safer, lighter and more efficient than any of its predecessors, with the company’s lightweight technology playing a key role in this advance.