The 2011 Formula 1 season saw engines become one of the talking points of the campaign, as the use of exhaust blown diffusers made headlines at the mid-season point of the championship. Outlawed for 2012, Renault Sport F1 deputy managing director Rob White explained why it was a key issue for Renault as an engine supplier.
Why have these changes come about and what are they?
The changes are intended to clear up some difficult points in the interpretation of the Technical Regulations. The subject kicked off in Barcelona last year, and reached the peak of its intensity at Silverstone. At the heart of the subject is the use of the energy in the exhaust gas stream to influence the aerodynamic performance of the car. Needless to say, the purpose was to make the car quicker, and exhausts became an important performance factor in the design and development of the 2011 cars and the collaboration between engine and chassis engineering teams was a performance differentiator.
Once the potential rules issue was identified (ie during the season last year), some restrictions were introduced with immediate effect to restrict the engine mapping used in the Standard ECU, which uses the same hardware, software, and restrictions for all teams. However the teams, along with the FIA, agreed to change the Technical Regulations concerning the position and orientation of the exhaust outlets on the bodywork for 2012.
The changes to the bodywork regulations for 2012 are intended to greatly reduce or even eliminate the effect of exhaust gases harnessed in this way. In addition, the engine mapping restrictions have been extended to further reduce the scope to generate exhaust gases that may be exploited.
In simple terms, the exhausts must now exit the car in a position limited by the Technical Regulations (typically high up rearward facing towards rear of the side-pod).
To combat the use of exhaust gases to give aerodynamic gain, the FIA has also imposed a set of limitations on the standard ECU. What does this mean?
As well as the Standard ECU (SECU) hardware, it is important to remember that the teams all use the same ECU software and only the calibration (mapping) may be used to adapt the SECU to the specificities of each engine and car. The further limitations concern therefore the way in which the teams may calibrate the control system to adapt it to the requirements of each combination of engine, car and driver. The restrictions apply mainly to the way in which the fuel and spark may be handled in the overrun phase and in the transition from closed to open throttle. Using engine mapping to generate higher energy than the exhaust stream would naturally have has now been limited.
Can you give us an example of what this involves?
A good example concerns when the driver lifts off the throttle pedal: he expects the car to slow down, ie for the engine to brake the car. The extent to which we may control the engine throttles, the spark and fuel is strictly limited. The closed throttle position is chosen to give the correct braking effect, we turn off the fuel to the injectors (for fuel consumption) but anticipate reinstating the fuel to re-wet the inlet tract, and we need to fire the ignition to avoid airbox fires. In a nutshell, there are many things that have nothing at all to do with the car’s aero performance that require us to fuel and spark the engine in ways which might not be immediately intuitive.
One often hears that Formula 1 is under a current engine freeze, whereby the design of the power units has been homologated for some time. How then is it possible to improve the performance of an engine, or for us to have witnessed such an engine-related controversy, in the middle of a freeze?
It’s important to remember that the words engine freeze appear nowhere in the rules. What is in the rules is a set of requirements that we have to comply with. The specification of the engine is not allowed to change and a further requirement is that we use the standard ECU. Every engine manufacturer would like to bring more performance to the car but that cannot do this by changing the spec of an engine that has already been homologated. So we can only operate on things that are outside the homologated perimeter, such as exhausts, or on parameters such as how the engine is operated in the car.
The debate wasn’t with the homologation of the engines or any changes to the specification; the subject that became controversial was the interpretation of Article 3.15 about the aerodynamic effect of exhaust gases, and it is very subtle.
The effect of this particular regulation has been tightened up this year, with additional regulations (for example concerning the ECU and exhaust locations).
With new regulations in place, the first challenge for the winter was to ensure that Renault’s plans were in line with the manner in which the FIA would apply the regulations. How has this effected your normal schedule of work?
The way the ECU and engines are operated affects quite a lot of the preparatory work going to the track. It is quite disruptive trying to turn that on its head from one day to the next, which is what caused trouble at Silverstone last year, but once you know what you are trying to achieve, you can set a plan that can be implemented without any real impact on the operations.
The target for the optimisation becomes a little bit different and the restrictions and constrictions of what you are allowed to do become different, then it becomes manageable.
We discussed in detail with the FIA how we would operate our engines to comply with the most recent instructions, agreed explicitly with them which control strategy within the standard software we needed to use for the purposes which have nothing to do with exhaust or aerodynamic reasons, and once we felt we had an understanding with Charlie Whiting and his team, we validated and calibrated the engine within the operating window that is allowed.
But with these new regulations in place, will be any knock on effect to engine reliability over the course of the 20 race season?
We’ve got the same durability requirement for this year and there’s no reason why any of these subtle changes should allow us to soften our ambition to maintain reliability. Performance is the headline subject but it goes hand in hand with reliability if you want to win races and championships. We try to take into account everything that moves in the environment, but in general, a quicker car is a car in which the driver has his foot on the gas for a longer period of time, so the engine is worked harder. Our job is to adapt to these changes and keep the engine performing to its best in each of the cars in which it is used.
There have been whispers that you’ve found other ways to get round the rules. Is this the case?
There were rumours that the Renault engine was producing noises on track that were similar to when running with the ‘blown diffuser’ exhausts and therefore we must be doing something carried over from last year. We all have the same mapping restrictions, and similar problems to solve, within the permitted limits.
Those limits exist to limit the scope to blow gas into the exhaust while permitting other normal operation of the engine. These are highly sophisticated, high performance engines and there are many other things going on within the power unit other than energising the exhaust gases. In over-run conditions, in the low speed conditions, in the conditions when we are changing from shut throttle to open throttle, there is a lot going on to keep these engines alive and to make the engines do what the drivers require us to do. Doing that means you have to do some stuff that is sometimes counter intuitive, and the side effects of that are maybe some popping and farting.
With winter testing at an end, and the 12 days of on track data now back at Viry, the countdown has begun to the first race in Melbourne. But with a championship to defend, how confident are you moving into this new season?
We have validated much of what we prepared on the dyno and, of course, it has been very useful to fine tune all of our human working relationships, especially as we have a new team this year in Williams which means we also have new people at the track. It’s not just the engines that get exercised in pre-season testing, it is the human part as well, and of course it is equally important to remember it’s not just what happens at the track that is important, but in parallel there’s a huge support network at the factory. I guess we are never completely satisfied, but we have been able to benefit from the ability to cross the t’s and dot the i’s in winter testing in terms of the engine spec and we can go to Melbourne pretty happy with our starting position.