|Category||Le Mans LMP1 Prototype|
|Chassis||Carbon-fibre composite and honeycomb monocoque|
|Suspension (front)||Double wishbones, push-rod actuated torsion bar springs and dampers|
|Suspension (rear)||Double wishbones, push-rod actuated torsion bar springs and dampers|
|Engine||3.7 litre V6 TDI 120º|
|Power||540 hp @ N/A rpmN/A lb-ft. of torque @ N/A rpm|
|Transmission||XTrac 6 speed Sequential|
|Fuel||Direct Fuel Injection|
|Debut||2011 6 Hours of Spa-Francorchamps|
|Designer||Designer (lead designer if it was a team effort)|
The Audi R18 TDI, is a Le Mans Prototype (LMP) racing car built Audi AG. It is the successor to the Audi R15 TDI. Like its predecessor, the R18 uses a TDI turbocharged diesel engine but with a reduced capacity of 3.7 litres and in a V6 configuration. For the first time since the 1999 R8C, Audi's Le Mans prototype uses a closed cockpit design. The R18 is also the first racing car from Audi to feature hybrid power.
As per the new rules for Le Mans in 2011 the car features a stabilisation fin on the engine cover and has a new 6-speed gearbox. The new gearbox is electrically controlled instead of pneumatically controlled, saving weight by eliminating the pneumatic system. Despite the capacity reduction, the 3.7L V6 is claimed to develop more than 397 kilowatts (532 bhp) of power. This is less than the outgoing R15, but the V6 engine's fuel consumption will more than likely be lower than that of the outgoing V10 engine on the R15. The new engine has a single Garrett TR30R VGT turbocharger, as opposed to the twin TR30R configuration of both the Peugeot 908 HDi FAP and the previous Audi R15 TDI.The R18's V6 engine exhausts inwards between the cylinder banks, where the turbocharger is placed. This is called a 'hot side inside' configuration and is opposed to the traditional configuration with each cylinder bank of a V engine exhausting outwards to their respective turbochargers.
The Audi R18 is the first ever LMP car to race with full LED headlights, in this case in the shape of the number "1." Unlike other coupé competitors in its class, the chassis on the R18 is not composed of two halves but rather a single-piece construction for improved rigidity. The R18 has an engine cooling duct above the cockpit roof as well as redesigned rear wheel arches to channel more air to the rear wing. Like the Acura ARX-02a, Audi has chosen to install bigger and wider tyres at the front for increased contact patch. Further changes include a lower rear wing, aluminium splitters and a small duct on the front of the car for improved driver comfort within the cockpit. The 2011 ACO regulations have limited the R18's fuel tank to 65 litres.
For 2012, Audi introduced an evolution of the original car called the R18 ultra. In addition to the changes required by the regulations (reduced air intake restrictor and 60 litre fuel tank) the car was completely reworked to reduce weight. These changes included a new carbon-fiber composite gearbox housing and changes to the one piece monocoque making the ultra the lightest Le Mans prototype that Audi Sport has ever built.
R18 e-tron quattroEdit
The R18 e-tron quattro is a hybrid version of the R18 ultra, utilising a Williams Hybrid Power designed flywheel accumulator system for energy storage which delivers 500 kJ to the front wheels via an electric motor, giving the car four (quattro) wheel drive. The system, as per the regulations, is only available at speeds above 120 km/h (75 mph). The car is fitted with a smaller 58 litre fuel tank.
The e-tron has six automatic modes that are driver selectable on the steering wheel. The modes manage engine mapping, short bursts accelerating from corners, quattro four wheel drive, wet weather, etc. Allan McNish said "I don't have to press a button ... It does it automatically ... It is like traction control."
2014-spec R18 e-tron quattro Edit
Changes from 2013 R18 e-tron quattro include the introduction of blue laser beam backlights with a yellow phosphor crystal lens complementing the LED headlights, a revised V6 TDI engine with an electric turbocharger, upgrades to the flywheel accumulator system and an exhaust heat recovery system. The system captures the thermal energy from the exhaust and can add power to either the turbocharger or the flywheel accumulator system. Audi later opted not to race with the second Energy Retrieval System, which is known as a Motor Generator Unit-Heat [MGU-H] in F1, because it did not result in the performance gain engineers had hoped for and was therefore considered an unnecessary risk to take. The aerodynamics have been heavily revised in accordance with the new rules: the width is reduced by 10 cm, the height is increased by 20 mm and there is a new set of front wings. However, the exhaust-blown diffuser on the 2013 model has been banned and removed. The safety monocoque has been strengthened with additional fabric. Wheel tethers and extra crash structures are also added to the car. Finally, there are numerous smaller upgrades to vision and ergonomics to improve drivability.
2015-spec R18 e-tron quattro Edit
In comparison to the 2014 car the 2015 R18 e-tron quattro's aerodynamics have been significantly improved and the turbocharged 4.0L V6 diesel engine now produces more power while using less fuel. The flywheel accumulator system's capacity has been increased from 500KJ to 700KJ as the 2015 Audi's energy output per round has been increased from 2MJ to 4MJ. Changes also include a significant increase of the hybrid system's power output.
2016-spec R18 Edit
On November 29, 2015, Audi Sport debuted the redesigned R18 that the team plans to race in the 2016 FIA World Endurance Championship season. The new R18 features significantly altered aerodynamics, including a raised nose similar to pre-2014 Formula One nose designs, air scoops above the front fenders, integrated mirrors, and other body modifications. The KERS for the 2016 R18 has also been changed from a flywheel system to a lithium-ion battery, and has been upgraded to the 6MJ class from the 4MJ class. The engine remains the same 4.0L turbodiesel V6. Audi has dropped the e-tron quattro name badge for the 2016 season.
Audi plans to race two R18s all across the 2016 WEC season. As of June 9th 2016, Audi has won both WEC events (in Silverstone and Spa Francorchamps); however an irregularity concerning the underbody of the winning car at Silverstone resulted in the winning car being outlawed; Audi decided not to dispute this decision.
GalleryEditAdd a photo to this gallery
Complete Racing ResultsEdit
(key) (results in bold indicate pole position)
|Audi Sport Team Joest||1||4||Ret||3||2||Ret||3|
|Audi Sport North America||3||3||Ret|
† - Result includes points scored by the Audi R15 TDI plus, which finished 4th and 5th in Round 1.
|Audi Sport Team Joest||1||16||2||1||1||2||1||2||3|
|Audi Sport North America||4||3||3|
|Audi Sport Team Joest||1||2||1||5||1||3||26||1||2|
|Audi Sport Team Joest||1||Ret||2||2||2||5||5||5||3|
|Audi Sport Team Joest||7||1||1||3||3||2||3||3||2|
|Audi Sport Team Joest||7||EX||5||4|
* Season in progress
Notes and referencesEdit
Please include any external sites that were used in collaborating this data, including manufacturer sites, in this section.
News and References
Enthusiast Sites and Discussion Forums
Audi R18 2016: обзор, фото и видео
В начале зимы 2015-2016 годов компания из Ингольдштадта порадовала всех поклонников марки и любителей автогонок своим самым быстрым автомобилем за всю историю. Речь идёт о гоночном автомобиле Audi R18 2016 модельного года.
Внешность болида изменилась за счёт полностью пересмотренного передка. При его создании дизайнеры и инженеры руководствовались, в первую очередь, улучшением аэродинамических характеристик Audi R18 2016.
Смотрите также все новинки модельного ряда Audi
Технические характеристики Ауди Р18 2016
В движение суперкар приводится шестицилиндровым дизельным V-образным агрегатом TDI рабочим объёмом 4 литра и электромоторами. Суммарная отдача гибрида пока держится в секрете, но, судя по предварительной информации, он стал мощнее прошлого поколения. Напомним, предшественник нового Audi R18 выдавал 830 лошадиных сил.
Технически Ауди Р18 лишился системы преобразования кинетической энергии при торможении в пользу увеличения емкости литий-ионных аккумуляторов. Кроме этого, новинка стала легче за счёт использования в конструкции кузова высокотехнологичных легких материалов.
Дебют нового Ауди Р18 намечен на середину апреля 2016 года. Первым делом автомобиль покажет себя в деле на трассе Сильверстоун в Соединённом Королевстве. Позже, создатели планируют заявить машину для участия в 24-часовом марафоне Ле-Ман и мировом первенстве гонок на выносливость WEC.
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Audi R18 (2016)
For the 2016 World Endurance Championship Audi Sport developed an all new chassis. This car which is the third distinct design to be called ‘R18′ carries over almost nothing from the 2014 variant (also used in 2015).
Most immediately apparent is the new monocoque used on the 2016 car, the proportions of the front end and the cabin within the overall vehicle length have changed, the roof is much flatter and the nose and front end of the tub is extremely tight with the front bulkhead smaller perhaps than those found on current F1 cars. “The new proportions influence weight distribution and aerodynamics,” explains Jörg Zander, Head of Engineering at Audi Sport. “Our most important objective was to improve airflow.”
At the front end, airflow has to be directed across the top of the race car and between the wheel wells, enter the cooling ducts through the body shell, and optimally approach the underfloor. “In this process, vortices must be avoided, as this costs energy,” says Zander. “Undesirable vortices and turbulent flow would reduce the energy in the airflow and increase resistance. The smaller the space which the monocoque occupies in this area the larger are the clearances for low-loss airflow.” The new tub believed to be developed by Ycom in Italy in conjunction with Audi Sport is reportedly lighter than the chassis used in 2014/2015. The monocoque consists of a high-strength CFRP structure with an aluminium honeycomb core. The cell has been provided with additional side impact protection, as Zylon layers integrated into the cockpit walls prevent the intrusion of objects.
This new concept required major work in other areas of the car especially round the front which is very tightly packaged indeed. Audi has been very reluctant to show off much of the detail around the front bulkhead and suspension of the car and is making great efforts to keep the mechanical components under cover making clear images hard to come by. (note the driveshaft) While the front suspension remains a double wishbone layout with push rod actuated spring-damper units the exact layout internally remains unclear as the damper and torsion bars are located deep in the monocoque and are simply not visible from the front of the car. It is known that the 2013/2014 F1 style interlinked suspension system is crucial to the cars aerodynamic performance. Note the drive shafts on the front end in these images. The car uses a hydraulic power steering system as well as an all-new high-pressure central hydraulic system, the details of which have yet to emerge.
The car’s power unit produces in excess of 1,000bhp with a combination of a four litre V6 mono turbo diesel engine and front axle mounted motor generator unit – kinetic (MGU-K aka KERS). From a internal combustion engine development stand point the V6 is particularly impressive, a combination of rule changes and an increase in the potency of the hybrid system on the car it has a much smaller fuel energy allocation than it did in 2015.
The basic concept of the V6 TDI engine dates to 2011. With its double-flow VTG mono turbocharger, 120-degree cylinder bank angle, the exhaust gas side within the V angle, and innovative detailed solutions the unit tends to be regarded as unusual. The initial displacement volume of 3.7 liters increased to four liters in 2014. “We’re now using the basic engine concept for the sixth consecutive year. This shows how sound the basic idea still is,” says Ulrich Baretzky. “Due to efficiency increases, we partially compensate for the lower amount of fuel.”
The current V6 TDI consumes 32.4 percent less fuel than the first generation did in 2011. This progress is even more substantial in comparison with the original Audi R10 diesel engine, the current engine uses 46.4 percent less fuel at Le Mans. Still, it achieves lap times that are ten to 15 seconds better than a decade ago.
The cars hybrid system is also all new, the GKN (nee Williams) Hybrid Power electro mechanical flywheel energy storage solution has been replaced by a battery electric system. “The flywheel accumulator definitely proved viable for the lower energy classes,” explains Thomas Laudenbach, Head of Electrics, Electronics and Energy Systems at Audi Sport. “But due to the fact that we now have to process even more energy than before, a technology change suggested itself.” Audi has stepped up from a 4MJ system to a 6MJ system. The production-based cells of the new hybrid storage system use ‘advanced and powerful cell chemistry’ (lithium-ion) and are serially connected. The battery pack is located in the tub (below) alongside the driver, note what appears to be a liquid pipe connector. The battery is linked to a single MGU-K mounted on the front axle. This motor is extremely potent but looking at the shape and size of the front of the tub it is clear that it is also quite compact. It appears to sit in front of the dampers, possibly for reasons of weight distribution. From the 2016 season on, there will be a track-specific limitation imposed on power output in addition to the previous energy classes. Although the MGU may recuperate any desired amount of energy, it may now only supply 300 kW (408 hp) in the race at Le Mans. Audi has designed its MGU for an output of more than 350 kW (476 hp) in order to recover as much energy as possible. The reason is that even when braking at high speed, the braking phases of an LMP1 race car last only three to five seconds. The high system output helps efficiently recover the required energy. At Le Mans, the system may only supply 300 kW during subsequent acceleration. Accordingly, the energy from the hybrid system will be available for a longer period of time. This limit does not apply to the other FIA WEC rounds.
In 2012, Audi started with about 150 kW (204 hp) of electrical power output. To date, this level has far more than doubled. Conceptually, the previous and the new MGU are akin to each other. However, the power electronics, stator, and rotor are new developments. This generation of the hybrid drive system delivers high output and develops strong torque, as a result of which the loads acting on the components that transmit power to the front axle increase accordingly. Audi uses a limited slip differential at the front axle to transfer torque with minimal loss.
The transmission is a new design as well, probably with much work done by Xtrac in England. ‘Audi’s simulations revealed that the optimised engine allows a very good gear ratio spread with minimal rpm jumps even in combination with a six-speed instead of the previous seven-speed unit. As a result, the engineers managed to further reduce the weight of the transmission.’ The mandatory wheel arch openings have been extensively reshaped and by regulation are 45% larger than those seen in 2015.
The brake calipers on the R18 come once again from Brembo. Almost none of the friction material is visible externally. (Front brakes above, rear below).
A look at the rear end of the R18 and its arrangement of outlets between the diffuser and rear deck.
The amount of aerodynamic detailing on R18 is unprecedented in LMP1. Almost every aspect of the car has a some kind of flow conditioner, turning vane or other appendage. Such as here looking rearward through the rear wheel arch.
Ahead of the rear wheels there is a stack of three vortex generator style elements on the side of the bodywork. Note the drag reducing wheel design.
On the inner face of the front fender there is a stack of three strakes, another example of the level of aerodynamic detailing evident on this car.
A look at the front fender in the high downforce Silverstone specification. It features a single dive plane and a small element on the outer edge.
The front wheel arch opening has an interesting shape at the rear edge where it terminates in a small slot on the inner face of the fender.
There is a small air outlet on the side of the bodywork behind the front wheel. Note the small turning vanes on the leading edge of the floor.
A look at the inner face of the nose, which illustrates how small the front bulkhead is. Note the mounting pins and the electrical connector (one assumes for the headlights and any sensors housed in the front bodywork). The opening on the tip of the nose appears to feed air though the nosecone and on through the bulkhead opening to the electric motor beyond.
A very vague look at the rear end of the R18 with the top of a cooler in evidence with some of its ducting. The rear wing pylon picks up on the top of the composite transmission casing. The rear suspension components are not visible as the R18 has a pull rod layout.
At the rear a lack of symmetry is evident, note the blisters on the centre of the bodywork on either side of the fin. The one on the left side of the car significantly larger than that on the right. Its not clear what they accommodate but the location appears to be related to the suspension. Note the twin exit exhaust (and recall this is a mono turbo engine).
Interestingly the arrangement of the vanes on the front of the car (above and below) has changed since its initial roll out and testing.
On the launch spec car the upper vane is much larger than the lower and the two appear to sit one above the other, but by the time the car arrived at the Prologue and Silverstone (below) the lower vane had become much larger than the upper and sits further forward.
The wing mirrors are faired into the side panels of the car. An approach seen previously and on other cars.
A look at the assortment of the turning vanes under the nose of the R18.
Audi R18 TDI
Chassis: Carbon fibre monocoque (Dallara) Class: LMP1 Engine: Audi Twin turbo 3700cc V6 Fuel: Diesel Transmission: Xtrac 6spd sequential Brakes: Brembo carbon ceramic Weight: – Fuel Tank: – Litres Year introduced: 2011
Audi aimed to continue its string of victories at the Le Mans 24 Hours with a completely new LMP1 sports car development. Since its debut in 1999, the brand with the Four Rings had won the world’s most important endurance race as many as nine times with the R8, R10 TDI and R15 TDI models. In doing so, Audi has equaled this feat in the race’s roll of honor with Ferrari. With the new R18, which was presented at the Audi Sportpark in Ingolstadt on the evening of Friday, December 10, 2010, Audi is aiming for its tenth Le Mans success in 2011.
How Audi Won Le Mans – Read all about how Audi R18 TDI successfully reduced power whilst increasing innovation in the preview below. Download the full July 2011 digital edition today
For the first time since 1999, Audi will contest Le Mans with a closed coupe again. “In the future, aerodynamic efficiency will be even more important at Le Mans than it was in the past,” says Head of Audi Motorsport Dr. Wolfgang Ullrich. “A closed car has clear advantages in this respect. Our computer simulations have been confirmed in the wind tunnel and during initial track tests.” Significantly smaller engines than those used before will be prescribed at Le Mans in 2011 as the rule makers aim to achieve a substantial reduction of engine power. By opting for a 3.7-liter V6 TDI unit, Audi retains the diesel concept that saw its first victorious fielding in 2006. “From our point of view, the TDI continues to be the most efficient technology,” says Ulrich Baretzky, Head of Engine Development at Audi Sport. “There are good reasons why the share of TDI units among Audi’s production models is as high as it is.”
Through the innovative V6 TDI engine for the Le Mans 24 Hours, motorsport is yet again performing pioneering work for the production arm at Audi where there is a growing trend towards smaller, more economical but yet powerful engines.
Another new development is the six-speed transmission in the R18 which has been specifically modified for use with the smaller engine.
With regard to the chassis Audi Sport wants to live up to its promise, expressed in the brand’s “Vorsprung durch Technik” tagline. Unlike those of the closed Le Mans prototypes, the carbon fiber monocoque of the Audi R18 TDI does not consist of two halves but features a single-component design. This saves weight and increases stiffness.
For the development of the closed Audi R18 TDI, engineers at Audi Sport were able to draw on the experiences gained in 1999 with the R8C and in 2003 with the LMP1 of the corporate “sister brand” Bentley that was victorious at Le Mans. “Also the Audi A4 DTM, which for example, features a heated windshield, allowed us to shorten the development cycle with respect to the ventilation of the cockpit, the doors and the heating of the windshield,” explains Dr. Martin Mühlmeier, Head of Engineering at Audi Sport.
The chassis and aerodynamics package contains a lot of know-how from the R8, the R10 TDI and the R15 TDI whereas the fitting of identically sized front and rear wheels is new to an Audi Le Mans sports car. This configuration allows a more balanced weight distribution.
The Audi R18 TDI’s headlights, which are the first to completely consist of LEDs with optimized amount of light, are a technical highlight. The new generation of headlights was developed in close cooperation between Audi Sport and the Technical Development (TE) division of AUDI AG and by using at Le Mans, will be prepared for future use in production vehicles. Audi’s light designers had the chance to make their mark on the development as well: The LEDs of the daytime light form the shape of a “1” which is intended to inspire associations with Audi’s historic brand logo.
The Audi R18 has been designed for progressive electrification, which Audi Sport is planning to drive forward step by step. “But efficiency is always the crucial factor for us,” says Dr. Wolfgang Ullrich. “No matter which form of energy recovery we may choose the key aspect for Audi – in motorsport as well as on the production side of the house – is that it provides a true advantage.”
The development of the new Audi R18 started in mid 2009. The V6 TDI engine has been running on the dynamometers since the summer of 2010. The R18, with Allan McNish at the wheel, completed its first test on a racetrack at the end of November.
The racing debut of the Audi R18 is planned for the Spa-Francorchamps (Belgium) 6 Hours on May 8. Prior to the event, the new prototype will be able to do its first laps on the race track at Le Mans during the official test day on April 24 and gather important data for the race on June 11 and 12.
“Lightweight design expertise expressed visually” is the principle under which Audi enters the famous 24 Hours of Le Mans this year. The three Audi R18 TDI cars, which join the grid for the French endurance classic on June 11/12 and which make their first public appearance over the Easter weekend at the Le Mans test day, perfectly embodies – also visually – Audi’s core expertise in lightweight technology. The livery of the three Audi Sport Team Joest Audi R18 TDI cars is dominated by puristic carbon fiber. The car of last year’s Le Mans winners carrying start number “1” even runs in the characteristic black of the extremely light and, at the same time, high-strength material, which also plays an increasingly important role in the development of new production cars.
“Carbon fibre is ideally suited for lightweight design and construction,” explains Head of Audi Motorsport Dr. Wolfgang Ullrich. “We have deliberately made this material and the ultra lightweight technology visual for Le Mans. Lightweight design has occupied us for many years in motorsport. Everything that we have learnt over the years and especially about lightweight design and construction during development of the R18 TDI will also be available for our customers in the future – either in the form of greater performance or in the shape of low fuel consumption and lower emissions.” The R18 TDI is a particularly authentic ambassador for the company’s lightweight technology which will be bundled by the term ‘ultra’ in the future. “Lightweight design is a very important factor at Le Mans because a light car is also always a more efficient car,” says Dr. Wolfgang Ullrich. This year, it is of even greater significance since the regulations stipulate smaller engines producing less power – for the Audi R18 TDI this means over 540 hp (397 kW). Although there is a minimum weight of 900 kilograms for LMP1 cars at Le Mans, the target is to produce a car weighing significantly less than this limit in order to optimize the weight distribution with the help of ballast and to lower the center of gravity as much as possible. “With the R18 TDI every component was optimized logically with regard to weight,” stresses Martin Mühlmeier, Head of Technology at Audi Sport. “The same applied to the chassis and the bodywork, the gearbox and the engine. We scoured the car for every superfluous gram.”
The carbon monocoque produced in a single-piece, for which a highly complex manufacturing process was developed and which is an impressive proof of the company’s lightweight design expertise, is not only revolutionary for a Le Mans sports car. The same applies for the bodywork which was lightened by 40 kilograms between the first and second version. “Such a consequent lightweight design is a high technical challenge,” says Christopher Reinke, Technical Project Leader at Audi Sport. The V6 TDI engine in the R18 TDI is about 25 percent lighter than the V10 TDI engine in its predecessor. “On one hand through downsizing, but also to a certain extent because we explored completely new directions and chose an unusual engine concept,” explains Ulrich Baretzky, Head of Engine Development at Audi Sport. The new six-speed gearbox, which has a high amount of carbon-fiber composite material, and the complete LED headlights also help to save weight. It was also possible to omit the electric cooling of the light-emitting diodes in the headlights commonly found in production cars. Because the gearshift is no longer activated pneumatically but rather electrically, the R18 TDI requires no more pneumatic system. Optimized airflow through the cockpit should make air-conditioning redundant. “The Audi R18 TDI is equipped with many innovative solutions,” says Head of Audi Motorsport Dr. Wolfgang Ullrich proudly. “It was built for regulations specifically targeting future technologies – and with the background enabling these technologies to be introduced into road going cars in the future. This is what makes sport prototypes so interesting for Audi. That we will now see the first impact of Audi ultra lightweight technology at Le Mans demonstrates just how motorsport and production line development go hand in hand at Audi. I’m convinced that ultra will be mentioned in one breath with terms like quattro or TDI in a few years.”
During the Le Mans test Audi was paying a lot of attention to the front tyre temperatures, with a laser temperature array mounted on top of the front arches.
Audi have been keeping their new Audi R18 TDI engine under very tight wraps, the above shot being the best so far. From this it appears that the exhaust system runs between the cylinder banks, however, the location of the turbos is not known.
The new Audi R18 TDI with which Audi targets its tenth victory in the famous 24 Hours of Le Mans on June 11/12 is ready today with “tomorrow’s” technology. During development of the new LMP1 sports car the integration and future electrification of the powertrain and various possible concepts for energy recuperation have been taken into account. We are very conscious of such systems,” explains Head of Audi Motorsport Dr. Wolfgang Ullrich. “In our opinion, just as soon as this technology proves to be the most efficient we will use it at Le Mans.”
Although diesel engines have been repeatedly restricted by the regulations since their victorious introduction in 2006, Audi relies on TDI power once again for its new LMP1. “Audi invented the TDI engine and is convinced that this technology remains one of the most efficient and modern forms to power a car – especially at Le Mans where engines with high specific power, low fuel consumption and low emissions are a necessity.”
New regulations devised by the Automobile Club de L’Ouest (ACO) and introduced this year dictate significantly smaller engines. Audi has chosen a particularly compact 3.7 liter V6 TDI engine, which is about 25 per cent lighter than the V10 TDI power plant previously fitted to the older R15 TDI, and which leaves all options open for the technicians with regard to electrification and energy recuperation. “This would not be the case with a V8, for example, which is also permitted by the regulations,” explains Ulrich Baretzky, Head of Engine Development at Audi Sport.
However, Audi does not only surprise with its extremely compact engine. The concept is also innovative for an LMP1 sports car. To lower the center of gravity as much as possible and to improve airflow through the car, the exhaust manifolds were migrated from the left and right hand sides of the engine to sit between the two cylinder banks. “Hot side inside” is the name given to this concept by specialists, which was implemented in similar form in Formula 1 in the 1980s. But the V6 TDI engine powering the Audi R18 TDI, which has a cylinder angle of 120 degrees and thus an extremely low center of gravity, is technically generations further along the line and is also a technology-demonstrator for future production engines.
In contrast to previous Audi Le Mans sports cars, which all had twin turbochargers, the R18 TDI is quite logically now only fitted with a single turbocharger that also sits above the engine and draws its air directly through the air scoop mounted on the roof. “In this way we are able to convert the dynamic pressure generated at high speeds with minimal losses into power,” explains Dr. Martin Mühlmeier, Head of Technology at Audi Sport.
The mono-turbo concept developed in cooperation with Garrett was only made possible by the variable turbine geometry (VTG) already used victoriously in the R15 TDI. “Otherwise the response characteristics of such a large turbocharger would just be too bad,” explains Baretzky.
The concept was continued logically through a single pipe exhaust that exits at the rear of the R18 TDI below the new fin which is stipulated by the regulations. “This also stands for Audi ultra lightweight technology,” says Baretzky, “since we save components and weight – for example for a second diesel particle filter.”
Audi Sport has worked since July 2009 on the innovative engine concept for which numerous new routes had to be explored. To control the enormous ignition pressures and loads now only distributed between six cylinders, a unique method of cooling the cylinder heads was developed for the aluminum power unit, a concept that could also be interesting in the future for production.
Owing to the compact engine and uncluttered flanks, the airflow from the coolers can now exit practically unobstructed through the rear end. “We could increase the aerodynamic efficiency of the car as a result,” says Martin Mühlmeier, Head of Technology at Audi Sport. This aspect is even more important than ever before at Le Mans due to the reduction in engine power – for the Audi R18 TDI more than 397 kW (540 hp).
Another unique aspect of the new Le Mans sports car is its unusual sound. The Audi R18 TDI is probably the quietest race car Audi Sport has ever built. “Noise is unused energy,” stresses Dr. Wolfgang Ullrich who is delighted by the whispering murmur of the R18 TDI. “The sound is unique,” raves Le Mans record winner Tom Kristensen. “It’s hard to describe. You have to hear it yourself. I think it’s fantastic.”
In the latest issue of Racecar Engineering we look inside the Audi R18 TDI. View the preview of the issue and subscribe here
Read about the Future of Motorsport according to the Audi team here
Audi R18 (2014)
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.