Chevrier talks about the engine for Brazil!

By role
October 19 2004

Denis Chevrier talks to Renault about the requirements for the engine at Interlagos in the upcoming Brazilian Grand Prix. After a series of less than good results renault F1 is looking forward to get back to the podium and finish the season on a high.

Chevrier talks about the requirements of the engine:

For the engine-builder, the first singular characteristic of Interlagos is that the circuit is located approximately 700m above sea-level. The atmospheric pressure, which is usually situated at around 1000 millibars, is therefore reduced to around 920. For any atmospheric engine, this reduction in air pressure brings with it an inevitable loss in power, as for a given volume of air, the percentage of oxygen - and therefore the potential for effective combustion - is lower. At Interlagos, the engine loses approximately 8% of its total power from the basic atmospheric pressure and the humid conditions which we often encounter at this circuit can also have an additional negative impact on performance.

In terms of layout, the circuit includes no very slow corners - the slowest of them, Turn 10, is taken at around 80kph. This means that the engine is not used at very low revs and that good levels of torque between 80 kph and 220 kph are important to launch the cars out of the many corners in the twisty second sector. Equally, the cars need to be able to change direction quickly and effectively while accelerating in this sector. As such, an engine which responds quickly and predictably to the driver's throttle inputs is an important advantage, as is smooth power delivery in order to maintain car balance.

In order to perform effectively, a strong torque curve must be combined with good levels of traction, particularly on the exit of Turn 12. Obtaining this good traction is complicated by the notoriously bumpy track surface in Brazil. As well as making life difficult for the drivers under braking by de-stabilising the car, the bumps can cause the rear wheels to lose contact with the track, thus potentially inducing over-revs while the car is under hard acceleration. This means that the safeguards implemented to prevent over-revs are particularly important at this circuit in order to ensure good engine reliability.

Finally, the small number of high-speed corners, coupled with the reduced engine power caused by the atmospheric conditions and the relatively short lap, means that both fuel consumption (2.4kg per lap) and the time penalty for carrying extra fuel (0.27s) are both comparatively low - both values are located below the season averages (3.0kg and 0.37s respectively).