How engine builders cope with the year's fastest race
The home of the Italian Grand Prix is arguably the toughest of all tracks for a Formula One engine. With well over two thirds of the lap spent at full throttle, and no low-speed corner sequences, there is simply no let-up for the engine during the punishing 53-lap event.
Though it doesnt feature the longest single period of full throttle (that honour goes to Indianapolis), the circuit does produce the highest average speed of the year at around 260 kph. This compares to just 160 at Monaco, and to an average of 220 across the season. Renaults Head of Engine Operations, Denis Chevrier, explains more:
This is the circuit where pure engine power has the biggest influence. The engine's maximum power is required for the longest period of any track we visit, with the driver demanding this level of performance from the engine for nearly 71% of the lap, as mentioned above. This high percentage of the lap spent at full throttle means that power has a proportionately greater role to play than on a circuit such as Monaco where the drivers use full throttle for just 40% of the lap. Conversely, though, this same nature of the circuit layout also means that the fuel effect here is relatively low, at 0.31s per ten kilos of fuel in the car.
However, Monza is not a completely one-dimensional challenge for the engine builder. The low-speed chicanes demand good driveability from the engine, and the ability to control power delivery as well as possible in order to let the drivers take the optimum line through the tight corners at Retifilo and Roggia.
Equally, the chicanes pose reliability risks in the form of the cars' passage over the severe kerbs. This subjects the entire car to sudden spikes in vertical acceleration and often sees the rear wheels lose contact with the ground. This has potential implications for engine over-revving, or hitting the limiter, and also transmission reliability. Equally, the suspension is highly loaded, and accessory components to the engine may undergo movement that can be harmful to their performance (the oil and water pumps, or the alternator, for example).
Like all the teams, Renault tested at Monza last week in preparation for the Italian Grand Prix, with Fernando Alonso topping the times on the final day.