Chassis: – Class: LMP1 Engine: V6 electro turbo compound, front mounted MGU Fuel: Diesel Electric Transmission: – Brakes: 0 Weight: – Fuel Tank: – Year introduced: 2013 (testing only)
Audi Sport has revealed its all new car built to the new 2014 LMP1 regulations in December 2013. The development of the car started in 2012. The roll-out took place in the early autumn of 2013 and a number of secret tests were conducted ahead of a private test at Sebring and its formal launch in Germany.
Audi claims that the 2014 car is the most complex race car it has ever built. The basic elements of the Audi R18 e-tron quattro’s new configuration were defined back in 2012 and the design of all the single components started at the end of 2012. The new car was rolled out in the early autumn of 2013, followed by track testing.
Audi has taken a brave decision not to compete with two Energy Recovery Systems and instead to run a single system, linked to the front axle, from which to charge up the flywheel storage system.
It is a strange choice given that Audi has worked hard to get to the full 0.5MJ release permitted by the regulations in 2012/2013, which equates to 4MJ/lap at Le Mans. Now, the limit is 8MJ and it seems likely that Toyota and Porsche will take the penalty applied to fuel consumption and run in the top class.
For Audi, to run in a lower release category means that it will play it safe, running with established systems after problems in testing. From the moment the cars started to test, there were rumours that only one system was capable of being used in the third generation R18, and it seems that Audi was never able to overcome the issue.
Audi has switched from Dallara to YCOM with its chassis supplier, as the team seeks to reduce weight and meet the new limit of 870kg for a hybrid car. ‘The next generation Audi R18 e-tron quattro represents a completely new generation of Le Mans prototypes,’ says Dr Wolfgang Ullrich, head of Audi Motorsport. ‘The principles of the LMP1 regulations have fundamentally changed. The idea behind this is to achieve similarly fast lap times as in the past with considerably less energy.’
Far from being an evolution, the V6 engine is completely new. ‘It is a brand new rulebook; the conception is completely new,’ says Ulrich Baretzky, head of engine design at Audi. ‘We could never do for 2014 what we did from 2012-2013. That would be the wrong way to go. We always have to save weight, but I don’t know how much we saved. The most important thing about the engine is that it has to last. We have saved some kilos, but we are not in Le Mans yet, tests are not finished yet, we have to wait until it is done.’
The loss of the MGU-H is less of a concern to the engine department than you might expect. ‘The MGU-H is less of an influence in the design of the engine, it is more complex in terms of overall energy management in the car,’ says Baretzky. ‘You have an amount of energy then you have to use it, and if you waste it you are lost. You have to have the management to do this, part of it by the driver, and some by the electronics.
‘The engine design methodology has not changed at all because it was always part of our job to run the engine efficiently. The only thing that has changed is the proportion; only economy or only power, and it has moved more towards economy. You have less quantities of pure performance in the lap than before to take the efficiency and to use the energy, because the energy is still used by the combustion engine, and nothing else.’
he flywheel now exactly fulfils our demands, which we have for the nw rules. Anything else would be stupid. It is the same principal, some components we took over. A hybrid system is a system. If you have an MGU with a max power of 170Kw, and a storage system capable of 100. You also need to work out how much storage do you need, and you don’t take more because it is weight.’
Audi has had another stab at improving its light system on the new generation R18 and has introduced a laser light system in addition to the LEDs that have come to be an iconic image of the car.
A blue laser beam backlights a yellow phosphorous crystal lens through which the light beam is then emitted. This new light source then provides even more homogenous lighting of the road.
The last time Audi introduced its super bright lighting system, it blinded the GTE drivers and was likely a contributory factor in Mike Rockenfeller’s accident in 2011.
“By using this new lighting technology Audi is setting yet another milestone at Le Mans,” said Dr. Ulrich Hackenberg, Member of the Management Board for Technical Development of AUDI AG. ‘Laser light will also open up completely new possibilities for our production models in the future.’
‘The new laser light is just one of numerous technical innovations featured by our new R18,” said Head of Audi Motorsport Dr. Wolfgang Ullrich. ‘We’re not going to reveal any more than that at this early stage, as in 2014 we’re facing an extremely tough competition and a year full of challenges for Audi Sport.’
Technical Analysis by Sam Collins
Audi’s chassis naming convention has stuck at R18, as this is the third LMP1 chassis to bear the name. The reason for this is because the Rx numbering system is copyrighted by Renault – and the R20 series and R30 series of numbers are the French firms most recent Grand Prix cars.
Audi has revealed that the R18 (2014) is an all new development, whilst visually similar to the 2013 car closer inspection reveals this to be the case.
The new car features a V6 TDI engine which is said to be ‘all new’ and not an evolution of the existing 3.7 litre unit raced in both of the previous R18’s. The front mounted electric motor concept carries over from the 2013 car but the MGU itself is also new. In addition to the front motor the car features a 2014 F1 style ‘electronic turbo-compound’ layout. Energy storage is once again in the form of a flywheel though scaled up. Something that comes as a surprise as many did not believe that the technology could be scaled up adequately. It could be that Audi is not using the full 8MJ allowed, indeed it is suspected that the car is using a 4MJ hybrid system.
As in the past, a Motor-Generator-Unit (MGU), during braking events, recovers kinetic energy at the front axle, which flows into a flywheel energy storage system. For the first time, the turbocharger of the internal combustion engine is linked to an electrical machine, which makes it possible to convert the thermal energy of the exhaust gas flow into electric energy – for instance when the boost pressure limit has been reached. This energy also flows into the flywheel energy storage system. When the car accelerates, the stored energy can either flow back to the MGU at the front axle or to the innovative electric turbocharger, depending on the operating strategy.
In aerodynamic terms efficiency is the key for the new R18, the whole car is 100mm narrower with smaller tyres, this is a significant drag reduction. But the height of the car has to be increased to a minimum of 1,050 millimeters, 20 millimeters higher than before, and a larger cockpit is also mandatory, increasing drag. Interestingly Audi has not met this regulations by using a legality blister something evident on the Dome S103 and the Porsche 919.
With respect to designing the front end, the Audi engineers enjoyed new freedoms. Instead of a diffusor, a genuine front wing with a flap may be used for the first time (common to all 2014 rules LMP designs). This promises aerodynamic advantages and lower costs, as this part of the bodywork will lend itself to easier modification to suit the various race tracks. In the past, it was necessary to produce different bodywork assemblies.
On the other hand the blown diffuser used on the 2013 R18 has been banned.
So the exhausts currently exit on the car centreline. It is believed that Audi has once again found a way to optimise the exhaust gasses, perhaps in an attempt to reduce drag.
The chassis itself has to be stronger to be able to withstand higher loads. At the same time, it is reinforced by additional layers of fabric, which are hard to penetrate in the case of a concentrated impact. This reduces the risk of intrusion by pointed objects in accidents. Another safety change is the introduction of wheel tethers. They connect the outer assemblies of the front wheel suspensions with the monocoque and the ones of the rear suspensions with the chassis structure as is common in F1. Each of the two tethers required per wheel can withstand forces of 90 KN – which equates to a weight force of nine metric tons. Another new feature is a CFRP rear impact structure behind the transmission (below).
The R18 shown off at the Audi Sport Finale party featured a curious cooling duct (below) just behind the cockpit. When asked about its function all Christophe Reinke would say is “this is not the final bodywork.”
A look along the side of the car reveals a outlet duct apparent on the 2013 R18 has carried over, the bulge in the bodywork below the fuel flow meter connectors is of uncertain purpose.
It has been widely noted that the front of the monocoque is much tighter and more waisted than that of the 2013 car.
This section of the car also houses the front motor, judging from the size of the driveshafts it is a more potent (larger) unit than that used in 2013.
Some early development work on the 2014 R18 was conducted at Le Mans in 2013 when Audi ran its very secret ‘black beauty’ on the test day. This car was equipped with the now mandatory narrow Michelin tyres along with some other technologies which Audi refused to disclose.
Audi has chosen to place its mandatory air extraction holes on top of the wheel arches instead of the inner face where it is also allowed. Interestingly the design shown is very basic compared to the version run on the 2013 car (below)
The Audi R18 e-tron quattro did not only cause a sensation on its drive through Le Mans due to its striking livery. At the beginning of a fundamentally new technological era, Audi published the key technical data of the race car’s powertrain as well. For instance, the cubic capacity of the V6 TDI power plant was increased from 3.7 to four liters in order to further optimize the engine that had already been very efficient. After testing various energy recovery systems, Audi decided to compete in the class of up to two megajoules of recuperation energy at Le Mans. The energy exclusively flows through a motor generator unit (MGU) at the front axle and is stored in a flywheel energy storage system. “We opted for this concept following extensive testing,” says Head of Audi Motorsport Dr. Wolfgang Ullrich. “In our opinion, it provides the optimum balance between efficient energy use, size, weight, energy conversion efficiency, responsiveness, drivability and a favorable operating strategy – combined with durability, which is the basic prerequisite for success at Le Mans.
RACE 01: SILVERSTONE
A new rating shortly before the season opener aggravates the situation. The final energy allocation list was only issued before the season opener. Audi now has less fuel available per lap, the permissible flow amount has been lowered, the fuel tank capacity reduced by 0.5 to 54.3 liters and the inlet cross-section for refueling has become smaller for the R18 e-tron quattro. At the same time, the parameters for the LMP1 teams using gasoline engines have been raised.
But this not only poses an additional challenge to the engineers and technicians this season. The drivers significantly influence consumption by their driving style as well.
The two accidents at Silverstone were unfortunate for Audi in two respects. For the first time ever, the team of Head of Audi Motorsport Dr. Wolfgang Ullrich and Chris Reinke, Head of LMP, had to endure the retirement of all cars and the total loss of valuable championship points. The incidents caused considerable vehicle damage. The two monocoques of the hybrid sports cars were damaged. Consequently, cars number ‘1’ and ‘2’ had to be prepared again completely from scratch. As a result, the WEC World Champions at Audi are tackling an extreme workload between Easter and May 1.
RACE 02: SPA
The new R18 (no.3) has a different body that can be recognized at first glance by the longer rear overhang. Its use in Belgium is very valuable for the Audi engineers, as the data generated assists in validating the simulations which Audi previously performed. By the same token, the team can test how to handle the special body version and other technical modifications in racing conditions. The differences at the rear are conspicuous. The body is now flush with the rear wing and fully uses the maximum length of 4,650 millimeters. By contrast, the high-downforce version has a shortened body. The tailpipes differ as well. For Le Mans, they do not exit to the right and left of the central fin but at the body surface above the diffusor.
The new specification R18, features a number of very interesting differences to the high downforce version. Audi has fitted an entirely new exhaust layout to the car (above), instead of a single pipe from the turbo running to the rear of the fin as seen at Silverstone the new specifications has two pipes mounted much lower and wide apart.
Audi engineers would not be drawn on the specifics of the layout other than insisting that the engine still uses a single turbocharger.
The shape of the rear deck has also been heavily revised compare the new specification version (above) with the old (below). Note also the small turning vane behind the rear wheels on the new version.
The new specification R18 sees the mandatory holes on the front wheels pods moved from the top to the inner face. The rear end of the pd has also been milady reshaped. The sticker on the inner face of the rim blanking just visible suggests that this car is chassis 6. Audi destroyed two tubs at Silverstone and it is believed that the car running as no.3 at Silverstone was in fact the newest build prior to the opening WEC round, suggesting that as many as 8 R18’s have been built ahead of Le Mans.
Standing slightly to the rear of the low drag R18 it is possible to get an idea of the airflow through the front of the car by looking through the louvres along the cars flank. In 2014 the LMP1 class cars are allowed to be fitted with what amount to fully adjustable front wings (yes this caption is also in the Porsche 919 article)
Some dirt on the engine cover of one of the high downforce specification cars at Spa revealed a little about the air flow over that section of the car. The R18 has its rivals scratching their heads in some areas as to why some things have been designed the way they are.
It is hard to tell too much from this image of the rear end of the R18, but there are some notable details. The roll hoop loads are carried by two members running diagonally downwards toward the bellhousing (though the exact pickup point is not visible).
The turbo housing region is just visible, albeit deep in heat shield material to the right of the image. Most interesting perhaps is the exhaust design, a straight pipe running rearwards from the turbocharger with a split at its tail end which gives the R18 its twin exits. What is not visible is the housing for a diesel particulate filter, its location remains unknown.
A look at the F1 style rear brake design on the Audi R18, the Brembo calliper is mounted at the leading edge of the brake disc, recent trends in other categories have seen the callipers mounted at the lowest point of the disc, it is not clear why Audi has not taken this approach.
A look could also be had of the whole rear end with the wheels and engine cover removed (above)
Glimpses of the front bulkhead could be had at Spa when one of the R18’s was in the pit with mechanical issues. In 2014 Audi has switched monocoque supplier to Italian firm YCOM. The shape of the front of the tub is very tight indeed considering it houses the cars MGU. The steering rack and suspension pickups are clear to see.
LE MANS TEST
The eight hours of testing at La Sarthe proved very valuable for Audi. During the four hours in the morning set up work was conducted. In addition to the final aerodynamic configuration, the mechanically generated grip was another focal point of the program. Furthermore, all eight drivers had the first opportunity at Le Mans to align their race cars and their personal driving styles with the energy consumption targets which the regulations specifically define for each track. In the morning, Marco Bonanomi, on setting a lap time of 3m 23.799s, achieved the fastest time in the first practice session.
The afternoons session was used for extensive tire tests and further aero tests. The objective was to test the performance of the fundamentally new tire generation over the long run.
Audi ran all three of its cars in low drag configuration at the Le Mans test, largely using the bodywork first seen at Spa. Much experimentation was done around the front of the cars with the inner face of the brake ‘cake tins’ of particular interest.
Attached to the inner face of the brake ‘drum’ is a fairly substantial turning vane (above). During the test Audi ran with these on both left and right front wheels initially, but then tried running the cars with only the right hand vane fitted, an unusual configuration which resulted in the cars fastest laps.
It has been suggested that this gives the car a different tyre usage, perhaps reducing wear or thermal degradation on the side with the vane removed. The brake performance is clearly part of the same system as when the vanes were removed the internal brake ducting within the ‘cake tin’ was also adjusted.
At least one of the Audi’s also ran with both left and right vanes removed entirely for some of the test session.
LE MANS 24 HOURS
Audi took an unexpected victory at Le Mans after every car in the LMP1 category was hit by problems during the race. The two Audi R18’s had turbocharger failures during the race (the third car crashed out early on).
On the starting grid the name of the winning no.2 car was revealed to be ‘Betty Boost.’
The duct behind the cockpit on the R18 has three distinct slit like apertures. It is not clear what the exact purpose of the duct is.
As with the 2013 R18 the headlamps have a very small cooling outlet above them on the front fender.
There is a depression in the top of the R18 monocoque, underneath the air box, this apparently gives some aerodynamic gains as well as cleaner airflow to the engine.
The exhaust layout on the low drag version of the R18 seen at Le Mans is remarkable with the tail pipes running through the upper wishbones. The layout is claimed to actually cost the engine power, but improves the cars overall performance due to the aero gains.
