The Lola Drayson B12/69 EV is Drayson Racing Technologies’ biggest green tech project to date and a collaboration between a number of our technical partners. The B10 Le Mans Prototype (LMP) car, which was originally powered by a 5.5 litre bio-fuelled Judd engine has been converted to pure electric drive. Our aim is to produce the fastest electric racing car in the world and one which show cases some of the best technology in the electric car industry.
Drayson Racing Technologies have designed a complete electric drivetrain which has been integrated into the existing chassis resulting in an extremely exciting package which produces zero emissions. Designed to the highest standards of quality and safety, this car is being used to develop drivetrain technologies and systems to be used in a wide variety of future projects from road to race and truly demonstrates the philosophy of using the racing track as a laboratory for the development of next generation electric car technologies.
(higher with ratio change)
|Power||640kW / 850Bhp|
|Active elements||Rear wing element
|Drag reduction from active system||30%|
|Motor||200kW axial flux (PMSM)|
|Inverter||750v, 400A CAN controller|
|Battery||Lithium Ion Phosphate|
|Transmission||Single ratio, split drive
Ratio: Track dependent
Safety is the highest priority at DRT. This is an area where we are using the project to improve industry learning and understanding on both general design and use of electric vehicles but also the maintenance and repair of these vehicles in high pressure situations.
DRT engineers have applied existing EV experience to the B12 system but are also working with industry experts, the FIA safety and medical teams and military high voltage system experts to develop new technologies and techniques to improve EV safety.
The B12 meets all road and motorsport electric drivetrain requirements and has been designed using expertise and analysis techniques previously applied to designing ASILD ISO26262 systems. The result is a system with multiple levels of failure tolerance comprising hardware and software, passive and active safety systems.
The design of the drivetrain followed an industry standard ‘V’ format. This involved a structured approach to the entire process with detailed and controlled documentation for all the key phases of the design. Key aspects include:
Simulation was a key to getting the design right before any commitment was made to components or designs. Various tools were used to simulate different key components and systems of the cars and help identify the optimum specification and layout of the car.
Working with various partners, the DRT engineers simulated all aspects of the car from the aerodynamics and chassis performance down to the high voltage electrical circuitry and control software on the car. This fed both into the specification and layout of the car as well as being used to prove the behaviour of key components prior to building the car.
Modern drivetrain and control systems are complex systems and require a clearly defined and analysed architecture for the physical and electronic makeup and information transfer of the system.
DRT engineers approached the B12 project by defining the top level System Architecture to give the optimum balance of safety, minimum complexity and maximum performance and reliability. This part of the design was key to ensure that the required safety and functional aspects of the system would be achieved as well as to identify requirements requiring addressing throughout the remainder of the design phase.
DRT designed low and high voltage systems form the backbone of the vehicle drivetrain. These systems are designed to be inherently safe and easy to use.
The high voltage systems manage both driving and charging and include numerous safety features and sensing systems. The low voltage systems incorporate multiple levels of redundancy as well as passive mechanisms which ensure the safety and integrity of the system before the software systems are even considered.
Electromagnetic interference and noise issues are regular stumbling blocks on internal combustion vehicles and can be significantly worse on EVs. Attention to detail of the design of the low and high voltage systems, sensor systems, chassis design and communication systems result in a system which is inherently robust to such interference.
Packaging and Cooling
Packaging and cooling of the main components was one of the major challenges of the project due to the need to integrate the EV system into a car originally designed for an internal combustion engine.
Using CAD tools (Computer Aided Design) design techniques the best possible layout was achieved with the minimum of compromises in safety, strength and weight. With these tools, the DRT engineers also evaluated the feasibility, simplicity and safety of key service and maintenance tasks which would have to be carried out in use.
Being pushed way beyond their original limits, the motor, inverter and battery systems required a lot of detail attention to be paid to thermal management. Working with the suppliers, DRT engineers optimised the existing cooling systems and identified key improvements which enabled the systems to be pushed to these limits.
Mechanical Structure and Design
This project was the first time that anyone had designed an electric drivetrain comprising stressed chassis members. The electric drivetrain needed to be capable of supporting the entire chassis loads endured driving flat out on the track including those expected during crashes.
This was no easy task but extensive use of CAD and FEA (Finite Element Analysis) allowed this to be done in parallel with the packaging and cooling system work to enable quick iteration through numerous options in very short periods of time.
Packaging the battery, motor and inverters within the confines of a race car proved highly challenging as the best balance of packaging efficiency, structural integrity, safety and serviceability had to be maintained.
The control system is the intelligence at the heart of an electric vehicle. DRT engineers designed the control systems for the B12 from first principles. Detailed specifications were produced and, working with technical partner Cosworth,the code was implemented and tested according to these specifications.
The system performs all vehicle control functions including:
This part of the system is where the key integration challenges were met to ensure that the subsystems which make up the drivetrain work together correctly and are controlled and managed appropriately.
DRT and our technical partners have used a range test rigs to prove the performance of all parts of the system. Key facilities include:
DRT engineers, using their prior experience of Formula 1, WRT and OEM projects, used a combination of the leading automotive and motorsport tools to methodically test, analyse and setup the complex calibration of the system to achieve the target performance, efficiency and reliability. This involved the precise setup of over 10,000 calibration parameters.
Designing an electric racing car requires looking at more than just the engineering of the car itself. DRT engineers focused on the functionality and layout of the controls to ensure a simple and intuitive interface for the driver; one which requires little knowledge of the system and minimum attention while on track. These controls incorporate safety mechanisms within their function and simple, logical feedback to allow a driver to quickly understand the health and operation of the car.