Thanks to its know-how in the design of aluminum structures, in 2005 Lotus developed a modular architecture technology named VVA (Versatile Vehicle Architecture) that will be used for a forthcoming range of sportscars.
The main scope of the VVA project is to bridge a gap in the investment-volume curve for the production at medium volumes (up to 50,000 units/year) of niche vehicles.
|Lotus Crossover rendering||Lotus Crossover rendering|
It will enable to differentiate niche products without the compromises of the conventional ‘platform sharing’. The first example of the VVA technology is the APX concept unveiled at the 2006 Geneva Motor Show.
From the official Press Release:
Constructed almost entirely from aluminium subcomponents, the understructure reveals the next stage in the development of the innovative technology. The structure reveals the high-pressure die cast corner nodes that are key to an architecture that additionally draws upon Lotus’ extensive experience with bonding and extruded aluminium.
“I’m very pleased to be able to demonstrate how far we’ve come with VVA,” explains Steve Swift, head of vehicle engineering. “The understructure proves the concept and we’re excited about the possibilities the technology brings to OEMs worldwide.”
“We expect that the demonstration of this technology through a real understructure will stimulate yet more interest from OEMs or consortiums looking to produce exciting products utilising cost efficient, proven architecture,” he adds.
Versatile Vehicle Architecture
Lotus VVA – Chassis StructureTraditionally OEMs seeking to gain competitive advantage through exciting niche vehicles have to either design a new platform or share one already available. Engineering a bespoke low-volume platform is an expensive, time-consuming solution, whilst sharing a mainstream chassis normally results in compromises in performance and design.
Lotus Versatile Vehicle Architecture (VVA) has been developed to bridge a gap in the investment-volume curve to exploit the benefits of producing at medium volumes but for niche markets, thereby giving the best chance of business case success and favourable returns.
VVA exploits Lotus Engineering’s expertise in aluminium, steel and composite body engineering, joining techniques, and vehicle systems integration. This innovative technology offers a fast-to-market, cost-effective approach to differentiated niche products by spreading the development, investment and bill of materials burden across a range of niche vehicle variants, without the compromise that stems from conventional ‘platform sharing’.
Lotus CUV UnderstructureThe philosophy is based on the commonality and versatility of key elements of the vehicle structure and body systems across a ‘family’ of niche vehicle variants, with a combined annual production rate of up to around 50,000 units. Structural components common to each family member are arranged in different configurations in each variant around the ingenious corner nodes.
The great advantage of this technology is that it can be used by one OEM looking to develop a range of niche products, or by a group of OEMs looking to share investment, but still retain a high degree of end product separation.
“We believe it is a technology that provides solutions to a wide range of manufacturers,” says Swift. “The worldwide vehicle market continues to sub-segment at a rate greater than its overall growth, leading to lower volumes per vehicle variant. OEMs are looking for architectures that give them a superior investment return with a high degree of product separation. VVA gives them that opportunity.”
The understructure is aluminium riv-bonded, consisting of high-pressure die-castings, stampings and extrusions, and uses advanced assembly techniques, including adhesive bonding, self-piercing rivets and flow-drill screws for construction.
The self-piercing rivets are used in a similar way to spot welding on a conventional steel shell, with the flow-drill screws used for single-sided access on closed sections. Both suffice to hold the structure together during the bonding cure cycle, and prevent adhesive joint peeling in the event of a crash.
The heat-cured high strength structural adhesive is the main joining medium, and used in combination with the mechanical fasteners, produces an immensely strong, durable joint and a lightweight shell with exceptional torsional stiffness.
|Lotus supercar understructure exploded view||Lotus supercar understructure|
Example VVA families
The following represents illustrative VVA families that could be achieved:
- Family A
- Front engine 4WD crossover 15,000 / year
- Mid engine RWD supercar 5,000
- Front engine RWD coupe 10,000
- Front engine RWD saloon 20,000
- Family B
- Front engine FWD coupe 10,000
- Front engine 4WD SUV 25,000
- Family C
- Mid engine RWD coupe 5,000
- Front engine FWD saloon 25,000
- Front engine 4WD crossover 30,000 – i.e. APX by Lotus Engineering