26 September 2008

Lotus Evora Aluminium Structure Celebrated

In what is the first award to be bestowed on the visually stunning Lotus Evora, even before production is underway, the award, only presented when special recognition is warranted, recognises the latest developments of this low volume version of the Lotus vehicle architecture technology. The European Aluminium Award is the leading international prize of the aluminium industry and was presented to Lotus at the prestigious International World Trade Fair ‘Aluminium 2008’ at Messe Essen in Germany on Tuesday 23rd September.

Mike Kimberley, Chief Executive Officer of Group Lotus Plc said: “We are absolutely delighted that the Lotus Evora has won such a prestigious award so soon after its official unveiling at the British International Motor Show in July. The Lotus Evora architecture is an advanced, lightweight technology that provides a foundation for our long term model plan for future Lotus and client products.

Kimberley continues: “This structure is the latest development of our vehicle architecture technology which was celebrated as the leading entry in the Aluminium Awards in 2006. The Evora heralds an exciting new era for Lotus Cars and proves that you can have phenomenal performance, fuel efficiency, elegant design and practicality all in a mid-engined 2+2 sportscar.”

A statement from the jury said: “Lotus provides an automotive structure with a unique approach. They combined adhesive bonding techniques with mechanical joining, resulting in innovative and creative solutions. Lotus used their expertise in lightweight materials to complete this structure, achieving a low weight and a high structural stiffness and therefore ensuring a major impact on environmental and sustainable performance.”

Richard Rackham, Vehicle Architect at Lotus Engineering said: “The Lotus Evora demonstrates an accumulation of our core competencies in aluminium and composite body engineering, jointing techniques and vehicle systems integration. Lotus pioneered the technology of bonded aluminium extrusions for use in road vehicles and has successfully developed high performance cars for other car companies around the world. One great advantage of our low volume vehicle architecture technology is that it can be used by one car manufacturer looking to develop a range of niche products, or by a group of car manufacturers looking to share investment, but still retain a high degree of end product separation.”

Lotus Evora Architecture
The Evora’s chassis is an evolution of the Lotus vehicle architecture from the Lotus aluminium crossover concept vehicle previously showcased at the Geneva Motorshow, and allows for the development of a range of vehicles up to a gross vehicle weight of 1,900 kg. This architecture has been designed to be more applicable to mid-volume applications by utilising low capital investment manufacturing processes. The Evora structure progresses the Lotus ‘bonded and riveted’ technology used in the Elise family of vehicles with unique extrusions and folded panels, whilst providing contemporary ease of ingress/egress, build modularity and improved, lower cost repairs.

The low volume versatile architecture has been designed so that it can be extended in width, length and height. The strength and stiffness of the low volume chassis can be modified cost effectively by varying the wall thickness of the extrusions, without altering the exterior dimensions. The ability to lengthen or shorten extrusions with the option to tailor the chassis stiffness vastly increases the number of vehicles that can be developed from this vehicle architecture. Front and mid engine installations have been considered, as well as hybrid and Electric Vehicle (EV) applications.

The Lotus Evora employs a composite roof as a stressed structural member to give an exceptional vehicle stiffness of 26,000 Nm per degree, thanks in part to the seatbelt anchorage frame’s secondary function as a roll over structure, and partly because the high-tech composite body panels are stressed items. However, despite this high stiffness, the complete chassis and modules weigh just 200 kg (prototype weight), helping to keep the weight of the whole car to just 1350 kg (prototype weight). To deliver this high performance structure, bonded and riveted high grade aluminium extrusions and simple, elegant folded sheet elements are used in the lower structure, which complements the stressed composite roof upper structure.

Attached to the high strength central tub are sacrificial energy absorbing subframes of extruded aluminium at the front and lightweight welded steel at the rear. These subframe modules also offer advantages in terms of convenience and low cost of repair, and during manufacturing can be brought to the production line fully assembled, ready to be attached to the fully assembled tub.

The high technology Lotus Evora chassis will be manufactured at the new Lotus Lightweight Structures facility in Worcester, UK. LLS employs 110 skilled engineers, technicians and sales staff and will manufacture all the Lotus aluminium structures, including those for the Elise, Exige, 2–Eleven and Europa and aluminium and composite structures and components for Lotus’s extensive global client base.