Renault explains engine mappings
After a German Grand Prix stirred by controversy over the engine mappings used on the Red Bull RB8, Renault Sport F1, the engine supplier for the Austrian team, sought to explain itself through Rob White and clarify the situation.
On the Sunday morning of the German Grand Prix, the Red Bull team was under investigation by the FIA for allegedly illegal engine mappings but was later cleared. However, the FIA was not pleased and moved to legislate on the matter within the week. The few days between the German race and the Hungarian round were therefore eventful, especially for Renault Sport F1, as the supplier of the Austrian team had to quickly adapt to the regulatory change.
Now that the situation has settled, the French manufacturer takes the opportunity to provide an explanation through an internal interview with Rob White, Deputy General Manager. Before addressing the controversy, he focuses on explaining what these famous maps are, numbering two: « The torque map in relation to the driver represents the torque requested by the driver based on engine speed and throttle position, he explains. « The engine torque map represents the torque delivered by the engine based on its speed and the opening of the air intake throttles [a part that pivots to let more or less air into the engine, ed.]. In the standard ECU, the engine map is used to position the throttles according to the driver’s torque request. »
The English also details the rules governing how to control engine torque: « This is covered by articles 5.5 and 5.6 of the technical regulations. The main points are:
– a part quelques exceptions, le couple du moteur doit être contrôlé par le pilote. […]
– le pilote ne peut contrôler le couple qu’au moyen d’une seule pédale d’accélérateur.
– à la position 0% de la pédale (pas de pression), la demande de couple doit être égale […] à zéro ; à la position 100% (à fond), la demande doit correspondre ou excéder le couple maximal du moteur (article 5.5.3).
– il y a des limites sur le forme de la courbe qui décrit la demande de couple en fonction de la position de la pédale et du régime moteur (pour empêcher que les caractéristiques du moteur qui se transforment en aides au pilotage).
By adhering to these rules, the torque request is tracked based on the position of the butterflies and the engine speed to deliver the desired response for the driver and the car.
According to him, it is not uncommon for mappings to change from race to race: « The driver’s mapping can change depending on the characteristics of the circuit. For example, drivers might want more precision when initially applying the pedal in Monaco. […] Engine mappings are also adjusted to take into account atmospheric conditions. Engines will all produce more torque on a cool day at Silverstone than at Interlagos (low pressure) or in Malaysia (high humidity). This ensures that the driver feels the same response from the engine regardless of the weather. Mappings can also be modified following changes in the exhaust or air intake […]. This week’s new FIA directive requires us to submit a reference mapping derived from the first four races of the season, from which we can deviate by plus or minus 2%. »
For Rob White, the problem highlighted at Hockenheim was merely a question of the magnitude of changes: « The FIA questioned the extent of differences between the mappings from Silverstone and Hockenheim, where the maximum torque of the engine at mid-range (from 10,000 to 14,000 rpm) was lower. » And the Englishman detailed the advantages of lower torque while trying to put possible gains into perspective: « Reducing the engine’s maximum torque curve increases the amount of exhaust gas produced at low torque, but very, very slightly, and it does not change the flow of gases at full load. Furthermore, the ability to use the engine to generate exhaust gases is extremely limited by the restrictions on mappings introduced for 2012, and also by the performance trade-offs […]. »
These disadvantages are of three kinds: « The trade-off concerns flexibility (the engine’s response to the pilot’s torque demand), acceleration (less torque means less acceleration, except if grip is limited), and fuel consumption. Generally, reducing torque is done by igniting the fuel later in the engine cycle […]. This can improve engine flexibility by smoothing the torque curve, which can help the driver preserve their tires. This is by no means a prohibited driving aid or an attempt to replicate the behavior of a banned system (for example, traction control). »
In conclusion, Rob White wants to reassure about the level of Renault engines this weekend. Thus, when he is asked if this has introduced any differences, the Englishman replies: “Not significantly, but the workload of our track engineers has increased to ensure we maintain the same level of performance.”
