- Feb 24th 2006 at 10:43AM
Lotus APX concept unveiled
Lotus Engineering released Friday specs and photos for its APX crossover concept, ahead of its official debut at the Geneva Motor Show next week.
In case you were wondering, APX stands for "Aluminium Performance Crossover." The concept car is a demonstration vehicle for Lotus' Versatile Vehicle Architecture, which will be the foundation for the upcoming Lotus mid-engine "super sportscar", slated for a 2008 launch.
The APX is a 4WD crossover with "5 2" seating. (In a refreshing bit of candor, Lotus calls the two rear seats "occasional." Other SUV and CUV manufacturers, please take note.) The APX is powered by a supercharged, front-mounted, 3-liter DOHC V6 designed by Lotus (!) and making 300 hp at 6250 rpm, good for 0-60 mph in 5.0 seconds (quicker than the Lotus Europa S). A symphony of cast, stamped and extruded aluminum, the APX weighs only 3454 lb, its light weight contributing to not only its sparkling performance, but also its impressive fuel consumption of 32 mpg.
Lotus says that the APX and its powerplant are not "concepts" but "feasible prototype(s) close to production," even though they are "not a concept indicating a strategic direction of Lotus Cars." Whatever. There's a lot going on at Lotus - the next couple of years should be interesting. More after the jump!
[Source: Group Lotus]
Lotus Engineering Press Release:
At the Geneva International Motorshow 2005 Lotus Engineering showed the
first example of a VVA understructure. This understructure is the basis for
APX. Traditionally 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.
The key to the VVA architecture is the high-pressure die cast corner nodes
that are combined with bonding, mechanical fasteners, extruded and pressed
aluminium. Lotus Engineering is a world leader in aluminium, steel and
composite body engineering, joining techniques, and vehicle systems
integration. The innovative VVA 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
The 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
The Engine - 300 hp, 3-litre V6
APX is a front engined and four wheel drive "Crossover" vehicle for
occasional off road use.
The V6 engine has been designed and developed by Lotus Engineering's
powertrain division. The directive for the project was to produce a high
performance prototype engine without the need to resort to exotic materials
or manufacturing technology, allowing manufacture around the world.
The supercharged V6 is part of a family of normally aspirated and
supercharged high performance engines which includes 2.2 litre and 3.0 litre
normally aspirated derivatives. All of these engines are at the prototype
stage and are production feasible, but are not currently planned for
The engine is production feasible and it is expected that the
commercialisation of this engine will be of interest to the automotive
clients of Lotus Engineering.
APX's engine is a supercharged 3 litre (2996 cc, Bore: 88 mm, stroke: 82.1
mm) V6 DOHC engine, mounted longitudinally in the front of the vehicle. It
uses a Rootes-type supercharger with a compact air - to - water Laminova -
type charge cooler with separate parallel coolant system using its own water
pump and heat exchangers allowing a charge temperature reduction of
approximately 50 degrees Celcius.
Performance of the engine is maximum power of 224 kW (300 hp, 304 PS) at
6250 rpm and a torque of 360 Nm at 4500 rpm. 80% of peak torque is between
1500 rpm and maximum revs of 6500 rpm.
Like all products from Lotus, it follows the adage of "performance through
light weight", in that the engine weighs just 171 kg (fully dressed, dry
weight). This gives a phenomenal specific output of around 1.31 kW/kg (1.7
hp/kg). Specific performance is 74.6 kW / litre (100 hp / litre, 101.3 PS /
This light weight comes from using cast lightweight aluminium alloy cylinder
block (with thin wall iron liners), aluminium cylinder head, and an
aluminium structural oilpan, able to support the front drive shafts. The
oilpan also includes coolant and lubrication channels to the oil cooler and
filter, and an electronic oil level and temperature sensor. Even the pistons
are lightweight - with each on weighing just 454 grams!
The construction of the V6 engine is arranged around the two banks of
cylinders at an angle of 75 degrees with a compact cylinder offset of just
32.5 mm. This allows the engine to be compact, with good vibration
characteristics, eliminating any requirement for balance shafts and the
related extra cost, weight, height and complexity.
The Engine Management System uses a state of the art 32 bit ECU processor
capable of over 200 million calculations per second. The ECU is Euro IV /
E-OBD and LEV/OBDII compliant.
And of course the engine satisfies the European End of Life Requirements
(ELV) with respect to recyclability and recovery.
The V6 engine is an example of extensive research into "engine downsizing by
Lotus Engineering's Powertrain Team. Engine downsizing is the concept of
using advanced technologies to enable a small engine to produce the power
and torque of a much larger engine, with the obvious reduction in fuel
consumption and emissions. One of the key demands of the automotive industry
is to produce engines with not only low emissions and high fuel economy but
also extremely good performance. These two demands for performance and
economy are not normally compatible unless there is a significant change in
the engine development strategy.
Like the vehicle, the engine is not just a Lotus Engineering concept, but a
feasible prototype close to production, however it is not a concept
indicating a strategic powertrain direction of Lotus Cars. The engine is
production feasible and it is expected that the commercialisation of this
engine will be of interest to the automotive clients of Lotus Engineering.
Prior to design release for the manufacture of this vehicle, the project was
subject to industry standard engineering processes to ensure a quality
product. Industry standard APQP processes have tracked and validated CAE
(Computer Aided Engineering - Computer analysis for strength, durability,
crash performance, Vibration, Aerodynamics, Fluid Flow etc), NCAP targets
for crash, pedestrian impact, torsion, bending and modal stiffness targets,
full static and dynamic CATIA V5 DMU (Digital Mock Up - Digital build of the
car to demonstrate the vehicle build and prove the fit of each part) to
minimise build issues and the full suite of Material and Process simulation
and validation to confirm manufacturing feasibility.
This coupled with tolerance analysis, full DFM/DFA (Design For
Manufacture/Design For Assembly) and advanced joining technology research
has been delivered in a true simultaneous engineering environment. The
vehicle build proved very successful with only a handful of build concerns.
A number of assembly validation builds were eliminated form the project
saving both time and cost essential for niche vehicle projects needing
'Right First Time' design and engineering philosophies to overcome tight
All significant components and structural items are made from Aluminium.
This means that APX weighs in at a sector leading light weight of 1570 kg so
even though it is not a Lotus car, it adheres rigidly to the fundamental
core values of the Lotus brand of "Performance Through Light Weight". Of
course lightweight structures are Lotus Engineering's forte and this is the
industry recognised area where the greatest improvements in performance and
fuel economy can be gained.
The understructure is riv-bonded aluminium, 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 adhesive cure cycle, and contribute to the performance of the
structure during both static and dynamic impact conditions.
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
The whole vehicle is 4697 mm long and 1852 mm wide. Wheel base is 2700 mm
and track is 1554 mm (front) and 1556 mm (rear).
The brief for Lotus Design was to create a visually arresting " Jekyll and
Hyde " car that fulfilled the needs of practical and flexible everyday
transport but also provided the enthusiast with a focused driving machine.
As with all crossover vehicles the solution is tailored to a specific niche
buyer who will instantly identify with these unique attributes.
Russell Carr, Chief of Design for Lotus explains: "We saw the customer as a
sportscar enthusiast who, with a typical family of 2 young children,
occasionally wants to carry four or five adults in addition to their
children. To facilitate this a third row of fold flat coupe style rear seats
are accommodated within the cabin."
The flexibility of the VVA platform system enabled the Lotus Design Studio a
rare opportunity to create a highly tailored solution that would meet, both,
the complex requirements of the occupant and technical package as well as
being aesthetically pleasing. The car has to look and feel like a sportscar
but accommodate a 5 2 seating package.
Russell Carr explains the exterior design philosophy: "We wanted the design
to communicate the driving experience of the car, which is characterised by
extreme power, performance and grip. Therefore the form language had to
convey strength and velocity whilst looking planted to the road. As with all
designs the essences of strength and movement are generated from stance and
proportion which are, on this car, characterised by an extreme cab rearward,
teardrop like silhouette and prominent wheel arches The illusion of speed is
further communicated by a taught, fluid form language within which feature
lines and surfaces stretch seamlessly from the penetrative nose to the boat
- tail rear end. Power is re- enforced by a prominent hood line, similar to
classic front engined sportscars, and flared arches, whilst strength is
given by a deep bodyside and coupe style slim glasshouse."
The brief for the interior of the car was to create an environment with the
visual drama of a sportscar but with a high degree of functionality and a
contemporary sense of luxury. Russell Carr explains further: "We started by
working with the engineering group to optimise the driving position and
major controls. Then we created memorable features and controls that combine
intuitive function with a unique design and high quality materials. This is
evident in the design of the HVAC control, the start button and instrument
pack. The latter communicates the cars sporting personality through a
distinctive sports bike look which mixes analogue and digital displays
within a high quality aluminium casing."
The digital screens of the instrument pack have multi-functionality enabling
major data, including Satellite Navigation, to be placed logically in front
of the driver. Great care was taken in developing the grains, textures and
material finishes to ensure an ambience of sportiness and contemporary
Example VVA families
The following represents illustrative VVA families that could be achieved:
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
Front engine FWD coupe 10,000
Front engine 4WD SUV 25,000
Mid engine RWD coupe 5,000
Front engine FWD saloon 25,000
Front engine 4WD crossover 30,000 - i.e. APX by Lotus Engineering