Q&A with Rob White - Renault F1 Chief Technical Officer

What are the challenges going into the second year of the power units?

Year two of a new engine is always difficult. The 2015 power unit project was started six months before the 2014 units took to the track, ie. before we had any significant experience of the technology. Then we also need to consider the issues arising during the season. It creates a need to be both forward thinking and reactive.

Splitting resources between projects is a delicate balancing act, in the short, mid and long term. While certain decisions can be taken upstream, a number of design decisions were taken quite late in the day, in order to benefit from the experience of the 2014 power unit. The result is a power unit that is very different to its predecessor.

What are the principal changes to the Renault Energy F1 for the 2015 season?

We have made some fundamental changes to gain performance and reliability. We have upgraded every system and subsystem, with items that will give the most performance prioritized. The principal changes involve the internal combustion engine, turbocharger and battery. The ICE will have a new combustion chamber, exhaust system concept and variable trumpets, as permitted by the 2015 regulations. The compressor is more efficient, while the energy recovery systems are able to deal with more severe usage.

The 2014 unit was already well placed in its centre of gravity, however we have tidied up the packaging to give greater ease of integration into the chassis. Additionally many systems and functions have been rationalized and simplified to further ease the task. In short, there are very few carry over pieces between the 2014 and 2015 power units.

This year the power unit is broken down into ‘tokens’. How does this system work?

This year there are regulatory limits to do with ‘token’ spend that determine the number of changes we can make. The power unit is divided into sections and then subassemblies associated to it. The total number of tokens within the power unit is equal to 66. Five out of the 66 tokens are not available for change as they are frozen. An engine manufacturer is able to select 32 token areas, or 48% of the engine, which he would like to change. As the technology gets more mature next year and beyond there will be fewer and fewer tokens available to spend. Clearly the juggling act we need to perform is which areas of the power unit are the most worthwhile to attack for performance reasons.

How has Renault decided to allocate its tokens?

We have used the majority of the tokens for the first race and our use of tokens during the course of the season will be relatively modest. It then becomes a matter of strategy about when you introduce the remaining tokens; whether to introduce at the start of the season when the technology is relatively immature but could give greater relative performance, or later in the season when the part has had more testing miles but the impact on performance will be potentially less. We can still make changes for reliability under the sporting regulations. We have therefore prioritized token spend to make as much headway as possible with performance.

What are your aims for 2015?

First and foremost we need to run reliably, be quick and closer to front. Our honest expectation is that we will make a decent improvement but it is difficult to quantify the gain relative to our competitors who will also progress. What we can say is that we are on course to make a significant performance step and resolve the principal reliability weaknesses by the time we get to the first race.