Abstract
This paper describes the methodological development of a modular system for rigid lightweight frames for race-cars which can alternatively be driven by a combustion engine, by a combination of a combustion engine and an electrical engine and by a combination of a battery and an electrical engine. This challenge is primarily resulting from the situation that a rather small team cannot develop individual race-car-frames for different applications. However, a similar situation can be observed in car industry where one car concept is intended to be used in combustion, hybrid and electrical applications in order to save development cost and to increase the production volume of many components including a large share of the car body.
The main assumption was that identical suspension systems, steering systems and braking systems and one general driver set-up (seat, steering wheel, pedals, cockpit) should be used for all set-ups, always allowing a lightweight, well-balanced (distribution between front and back axle and height of the centre of gravity) race-car. The race-car has to obey the rules for the formula student race competition. Especially the multitude of possible set-ups made the chosen task extremely difficult. If a combustion engine is used, only one general set-up with ONE central engine and a gear system can be observed. A considerably higher number can be observed if electrical set-ups are in the focus. Possible are central motors, motors for each axle, motors connected to each wheels e. g. by means of tie rods and finally rim motors. The placement of the battery is nearly free but largely determines the weight distribution. Furthermore, it is rather easily possible to create different battery shapes and to split the battery in several modules. Generally a low placement close to the centre of the race-car is desirable for excellent dynamic characteristics.
All possible drive-train set-ups were collected systematically by means of a morphological matrix and the resulting characteristics were determined. The driving capabilities were determined by means of straight-forward analysis and simulation. The most promising possibilities were designed in 3D-CAD and important characteristics were determined.
Keywords: race car frames, electrical vehicles, hybrid cars