PAVING THE WAY TO THE VEYRON

THE FOUR BUGATTI CONCEPTS FROM 1998 TO 2001

Once Volkswagen had acquired the Bugatti marque in 1998, the design teams started work right away. The aim was to create a vehicle that would be in keeping with the proud tradition of styling, performance and technical sophistication founded by Ettore Bugatti. Four design studies were produced in quick succession, and from these the Veyron was selected for development into a production model. In late autumn 2001, the design team set to work under the leadership of Karl-Heinz Neumann, who had previously been Volkswagen’s head of engine development. Contrary to the automotive industry’s usual practice, a design freeze was imposed at a very early stage – in other words, the engineers were committed to a basic design more or less from the outset. And they succeeded in turning this concept into a production model with only minor modifications.
Now the development phase began. The clay model was scanned into a computer, allowing the designers to work with it on their CAD systems. Details of the car’s kinematics – wheelbase, track, rolling circumferences, mounting points for the double wishbones and positions of the anti-roll bars and absorbers – were fine-tuned and finalised, and the specifications for the vehicle electronics were drawn up, so that work on these could progress paralell with the development of the engine and transmission. The team were very conscious of the fact that they were exploring uncharted design territory: the gearbox and drive shafts would be subjected to a level of torque previously unseen in sports car design, while the wheels and aerodynamics would have to handle unprecedented speeds of over 400 km/h – naturally while still complying with the Volkswagen group’s strict quality and safety standards. As a result, several prototypes were quickly built to allow for the data produced in electronic simulations by the Italian formula one specialists Dallara to be verified in practice. Even more importantly, however, this also meant that the thermal management systems of the 1001-horsepower car could be analysed in detail. By autumn 2003, it had become clear to the company’s management that the technological solutions developed so far would not suffice to achieve the project’s stated aims. When Dr. Neumann retired around this time, the board of Volkswagen AG were faced with a difficult decision: either they abandoned the project, or they started all over again. Fortunately, they chose the latter option.
Franz-Josef Paefgen, the CEO of Bentley Motors, was chosen to head up Bugatti Engineering, while the post of technical director was filled by Wolfgang Schreiber, Volkswagen’s former head of transmission development and the man responsible for the dual-clutch gearbox. Dr. Schreiber was given all the resources he needed, and the heads of the various technical areas had to report to him in the workshop every evening, in meetings that often lasted several hours. Participants in these sessions looked in detail at the status of every single prototype, reviewed the day’s test data and agreed on the next steps.
At the same time, quality assurance professionals and development engineers were despatched to every corner of Europe to meet with component suppliers, obtain their commitment to Bugatti’s quality standards and check the suitability of their processes. But what exactly was so unusual about the challenges posed by this project? The examples given below will throw some light on the extent and complexity of the problems that the designers faced. Engine: it was never the designers’ aim to build an engine with an output of over 1,000 horsepower; the aim was to build a car with a maximum speed of over 400 km/h.
However the aerodynamic constraints of the basic design meant that this amount of power turned out to be a necessary prerequisite. Given the parameters of a square engine, a maximum specific output of 125 horsepower per litre and a capacity of 0.5 litres per cylinder, a 16-cyclinder engine was the logical solution. To keep the engine compact, the team chose to make use of Volkswagen’s proven VR technology, which, thanks to a cylinder bank angle of just 15 degrees, allows the two cylinder banks in the V configuration to share a single engine block.
In the Bugatti, two V8 arrays using this design are connected to a single crankshaft to create a 16-cylinder W-engine, with four camshafts and 64 valves. Four turbochargers and two intercoolers make sure the cylinders receive sufficient air, while four catalytic converters ensure the car comfortably complies with applicable emissions regulations. Transmission: thanks to the dual-clutch gearbox – which at the time was a very new technology – the car’s awesome power can be delivered to the wheels without interruption.
However, nobody had previously tried to use this kind of gearbox with seven gears and 1,250 Nm of torque, or indeed with a four-wheel drive layout.
As a result, an all-new gearbox had to be designed and built, in collaboration with British transmission specialists Ricardo. The key tasks were to set the parameters for the power distribution, strengthen the gear linkages, successfully incorporate a separate gearbox oil circuit, minimise noise, and ensure the durability that customers rightly expect of a Volkswagen-group vehicle. Carbon fibre chassis: to achieve the perfect balance between weight and safety considerations, the designers opted for a carbon fibre monocoque design of the sort commonly used in Formula one, despite the ensuing high costs.
The company had no experience to speak of in working with carbon fibre, and so the team had to work out the principles of the technology for itself as they went along – for example, over 1,000 connection points and screw thread inserts were made and tried out in different positions. To prevent contact corrosion, all-new bolts and inserts were developed, made of titanium. Torsional rigidity is essential not just for crash safety, but also to a car’s handling when driven to the limit. As a result, a lot of effort was put into optimising the layer structure of the carbon fibre sheets in the individual components, and into experimenting with different weaves, lamination techniques and core materials.
The end result was a recordbreaking torsional rigidity of over 50,000 Nm per degree. Driving dynamics: as with any road-going vehicle, the designers of the Bugatti Veyron wanted to ensure their creation remained fully controllable in any situation. The enormous tyres (265-680 ZR 500 at the front, 365-710 ZR 540 at the rear), vast reserves of power and the uncompromising design of the braking system all enabled the car to break new ground in this regard. The combination of sophisticated construction techniques with the best materials available enables the Veyron to accelerate from 0 to 160 km/h and brake to a standstill in
less than nine seconds.
The cornering acceleration of over1.25 g also puts considerable vertical dynamic stress on all the car’s components. An array of electronic systems work together to ensure maximum safety and responsiveness: programming the ESP to compensate for the difference in the number of wheel revolutions between front and rear axles resulting from the staggered tyre sizes was one of the simpler challengesthat had to be overcome. The system also had to help regulate engine braking, process data from the gearbox and the Haldex clutch, and communicate with the braking pressure control system and rear differential lock.
And of course, the interaction of the various systems had to be constantly refined in countless rolling road and track tests. Lightweight construction: as was alluded to above, when the projectwas relaunched under Wolfgang Schreiber it quickly became clear that the car’s weight was getting out of hand. Quite apart from the general design imperative for a sports car to minimise weight, there was also a very real danger that the car would not be granted approval for road use. Reducing the weight thus became a priority, and the designers were not afraid to make use of unconventional solutions and unusual materials.
For example, the exhaust, axle springs, brake disc hats and heat shields were made of titanium, while valve and intercooler covers were made of magnesium. Special aluminium alloys were formulated for use in very thin components such as the radiator hoses, wings and doors, and extensive use was made of carbon fibre.
Even the onboard electronics systems were redesigned, with special lightweight cabling of a type that had previously only been used in aircraft and racing cars.
The various lightweight construction techniques employed resulted in a total weight saving of almost 200 kilograms. Thanks to an enormous amount of hard work by all the team, the project was completed on schedule and, in October 2005, the car was unveiled to the world’s press in Sicily. The last few remaining issues were ironed out over the following weeks, and the first customers took delivery of
their cars in early 2006.

DEVELOPING THE BUGATTI VEYRON 16.4

THE TECHNICAL BACKGROUND

Once Volkswagen had acquired the Bugatti marque in 1998, the design teams started work right away. The aim was to create a vehicle that would be in keeping with the proud tradition of styling, performance and technical sophistication founded by Ettore Bugatti. Four design studies were produced in quick succession, and from these the Veyron was selected for development into a production model. In late autumn 2001, the design team set to work under the leadership of Karl-Heinz Neumann, who had previously been Volkswagen’s head of engine development. Contrary to the automotive industry’s usual practice, a design freeze was imposed at a very early stage – in other words, the engineers were committed to a basic design more or less from the outset. And they succeeded in turning this concept into a production model with only minor modifications.
Now the development phase began. The clay model was scanned into a computer, allowing the designers to work with it on their CAD systems. Details of the car’s kinematics – wheelbase, track, rolling circumferences, mounting points for the double wishbones and positions of the anti-roll bars and absorbers – were fine-tuned and finalised, and the specifications for the vehicle electronics were drawn up, so that work on these could progress paralell with the development of the engine and transmission. The team were very conscious of the fact that they were exploring uncharted design territory: the gearbox and drive shafts would be subjected to a level of torque previously unseen in sports car design, while the wheels and aerodynamics would have to handle unprecedented speeds of over 400 km/h – naturally while still complying with the Volkswagen group’s strict quality and safety standards.
As a result, several prototypes were quickly built to allow for the data produced in electronic simulations by the Italian formula one specialists Dallara to be verified in practice. Even more importantly, however, this also meant that the thermal management systems of the 1001-horsepower car could be analysed in detail. By autumn 2003, it had become clear to the company’s management that the technological solutions developed so far would not suffice to achieve the project’s stated aims. When Dr. Neumann retired around this time, the board of Volkswagen AG were faced with a difficult decision: either they abandoned the project, or they started all over again. Fortunately, they chose the latter option.
Franz-Josef Paefgen, the CEO of Bentley Motors, was chosen to head up Bugatti Engineering, while the post of technical director was filled by Wolfgang Schreiber, Volkswagen’s former head of transmission development and the man responsible for the dual-clutch gearbox. Dr. Schreiber was given all the resources he needed, and the heads of the various technical areas had to report to him in the workshop every evening, in meetings that often lasted several hours. Participants in these sessions looked in detail at the status of every single prototype, reviewed the day’s test data and agreed on the next steps.
At the same time, quality assurance professionals and development engineers were despatched to every corner of Europe to meet with component suppliers, obtain their commitment to Bugatti’s quality standards and check the suitability of their processes. But what exactly was so unusual about the challenges posed by this project? The examples given below will throw some light on the extent and complexity of the problems that the designers faced. Engine: it was never the designers’ aim to build an engine with an output of over 1,000 horsepower; the aim was to build a car with a maximum speed of over 400 km/h.
However the aerodynamic constraints of the basic design meant that this amount of power turned out to be a necessary prerequisite. Given the parameters of a square engine, a maximum specific output of 125 horsepower per litre and a capacity of 0.5 litres per cylinder, a 16-cyclinder engine was the logical solution. To keep the engine compact, the team chose to make use of Volkswagen’s proven VR technology, which, thanks to a cylinder bank angle of just 15 degrees, allows the two cylinder banks in the V configuration to share a single engine block.
In the Bugatti, two V8 arrays using this design are connected to a single crankshaft to create a 16-cylinder W-engine, with four camshafts and 64 valves. Four turbochargers and two intercoolers make sure the cylinders receive sufficient air, while four catalytic converters ensure the car comfortably complies with applicable emissions regulations. Transmission: thanks to the dual-clutch gearbox – which at the time was a very new technology – the car’s awesome power can be delivered to the wheels without interruption.
However, nobody had previously tried to use this kind of gearbox with seven gears and 1,250 Nm of torque, or indeed with a four-wheel drive layout.
As a result, an all-new gearbox had to be designed and built, in collaboration with British transmission specialists Ricardo. The key tasks were to set the parameters for the power distribution, strengthen the gear linkages, successfully incorporate a separate gearbox oil circuit, minimise noise, and ensure the durability that customers rightly expect of a Volkswagen-group vehicle. Carbon fibre chassis: to achieve the perfect balance between weight and safety considerations, the designers opted for a carbon fibre monocoque design of the sort commonly used in Formula one, despite the ensuing high costs.
The company had no experience to speak of in working with carbon fibre, and so the team had to work out the principles of the technology for itself as they went along – for example, over 1,000 connection points and screw thread inserts were made and tried out in different positions. To prevent contact corrosion, all-new bolts and inserts were developed, made of titanium. Torsional rigidity is essential not just for crash safety, but also to a car’s handling when driven to the limit. As a result, a lot of effort was put into optimising the layer structure of the carbon fibre sheets in the individual components, and into experimenting with different weaves, lamination techniques and core materials.
The end result was a recordbreaking torsional rigidity of over 50,000 Nm per degree. Driving dynamics: as with any road-going vehicle, the designers of the Bugatti Veyron wanted to ensure their creation remained fully controllable in any situation. The enormous tyres (265-680 ZR 500 at the front, 365-710 ZR 540 at the rear), vast reserves of power and the uncompromising design of the braking system all enabled the car to break new ground in this regard. The combination of sophisticated construction techniques with the best materials available enables the Veyron to accelerate from 0 to 160 km/h and brake to a standstill in
less than nine seconds.
The cornering acceleration of over1.25 g also puts considerable vertical dynamic stress on all the car’s components. An array of electronic systems work together to ensure maximum safety and responsiveness: programming the ESP to compensate for the difference in the number of wheel revolutions between front and rear axles resulting from the staggered tyre sizes was one of the simpler challengesthat had to be overcome. The system also had to help regulate engine braking, process data from the gearbox and the Haldex clutch, and communicate with the braking pressure control system and rear differential lock.
And of course, the interaction of the various systems had to be constantly refined in countless rolling road and track tests. Lightweight construction: as was alluded to above, when the project was relaunched under Wolfgang Schreiber it quickly became clear that the car’s weight was getting out of hand. Quite apart from the general design imperative for a sports car to minimise weight, there was also a very real danger that the car would not be granted approval for road use. Reducing the weight thus became a priority, and the designers were not afraid to make use of unconventional solutions and unusual materials.
For example, the exhaust, axle springs, brake disc hats and heat shields were made of titanium, while valve and intercooler covers were made of magnesium. Special aluminium alloys were formulated for use in very thin components such as the radiator hoses, wings and doors, and extensive use was made of carbon fibre.
Even the onboard electronics systems were redesigned, with special lightweight cabling of a type that had previously only been used in aircraft and racing cars.
The various lightweight construction techniques employed resulted in a total weight saving of almost 200 kilograms. Thanks to an enormous amount of hard work by all the team, the project was completed on schedule and, in October 2005, the car was unveiled to the world’s press in Sicily. The last few remaining issues were ironed out over the following weeks, and the first customers took delivery of their cars in early 2006.

Bugatti SAS

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Ce qui a été déjà inventé appartient au passé, seules les innovations sont dignes d'intérêt - Ettore Bugatti

Thanks. Was very interesting to read.

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Old name: D55L