The 80th International Geneva Motor Show sees Lotus Engineering unveil
the Lotus Evora 414E Hybrid concept, a high performance technology
demonstrator with a plug-in series hybrid drive system and new
technologies for enhanced driver involvement.
0-60 mph (97 kph) in under 4 seconds
Total hybrid range of over 300 miles (483 kilometers)
Eco mode or Sports mode featuring realistic 7-speed paddle shift
with energy recuperation
HALOsonic Internal and External Electronic Sound Synthesis
Torque vectoring for improved dynamic stability
Integrated glass roof and engine cover and interior concept from
Lotus Design
The Lotus Evora 414E Hybrid, so-named because this latest environmentally focused
technology demonstrator from Lotus Engineering produces 414 PS of power (408 horsepower), promises breathtaking performance from a highly efficient propulsion
system. The concept showcases new developments in plug-in, range-extended electric
propulsion, new electronic technologies to enhance driver involvement, the adaptability of
the Lotus Versatile Vehicle Architecture (VVA) that underpins the Evora 414E Hybrid and
a dramatic new roof system and interior concept from Lotus Design. Through all of these
aspects it ultimately demonstrates the exceptional ability of Lotus Engineering to
integrate and develop advanced technologies for exciting, efficient, high performance
niche vehicles.
The range extended electric drive of the Evora 414E Hybrid consists of two electric
motors driving each of the rear wheels independently via a single speed geartrain,
integrated into a common transmission housing, thus enabling torque vectoring for
stability control of the vehicle. Electrical power is stored in a lithium polymer battery pack
optimized for energy density, efficiency and high power demand, mounted in the center
of the vehicle for stability and safety. Additional range is provided by the Lotus Range
Extender engine, an optimized 1.2 liter, three-cylinder engine, designed specifically for
series hybrid vehicles. The drivetrain is designed to combine astonishing performance
with efficient, low emissions driving.
Driver involvement is enhanced by the incorporation of HALOsonic Internal and External
Electronic Sound Synthesis technologies from Lotus and Harman International, which
provide sound contouring within the cabin and improve pedestrian safety outside the
vehicle. Integrated with the HALOsonic technology, the Evora 414E Hybrid also
showcases a brand new technology from Lotus Engineering, a sports mode that
simulates a 7-speed, paddle shift transmission that combines exceptional driver
involvement for a hybrid sports car and optimized energy regeneration.
The Evora 414E Hybrid has been designed to highlight Lotus’ innovative electric and
hybrid vehicle technology without distracting from the pure sports car character of the
Evora. The solution is innovative, instantly recognizable, beautiful and sporty. It
demonstrates Lotus DNA.
Dr Robert Hentschel, Director of Lotus Engineering said: “Innovation has always been at
the heart of Lotus and is needed now more than ever. The Evora 414E Hybrid is the
perfect demonstration of Lotus Engineering’s core competencies: lightweight
architectures, efficient performance, electrical and electronics integration and driving
dynamics. The technology demonstrator represents an encapsulation of the advanced
technologies that Lotus Engineering continues to develop to overcome the current
environmental challenges facing the automotive industry and showcases the future
direction that the sector is taking and why Lotus Engineering is perfectly placed to lead
the technological development in this area.”
The Drivetrain
For the Lotus Evora 414E Hybrid, Lotus Engineering has developed a highly efficient,
high performance drivetrain system consisting of twin motors each limited to providing
152 kW (207 PS/204 hp) of power and 400 Nm (295 lb.-ft.) of torque to each wheel via
independent, single speed, reduction transmissions integrated into a single housing,
enabling torque vectoring dynamic control of the vehicle.
The vehicle energy storage system is made up of the latest Lithium Polymer battery
chemistry providing 17 kWH energy storage capacity. The battery pack is optimized for
energy density, efficiency and high power demand, with over 300 kW discharge
capability.
The Lotus Range Extender engine provides 35 kW (48 PS/47 hp) of power at 3,500 rpm
via the integrated electrical generator and features an innovative architecture comprising
an aluminum monoblock construction, integrating the cylinder block, cylinder head and
exhaust manifold in one casting. This results in reduced engine mass, assembly costs,
package size and improved emissions and engine durability. The engine uses an
optimized two-valve, port-fuel injection combustion system to reduce cost and mass and
can be operated on alcohol-based fuels and/or gasoline. The generator converts
mechanical energy to electrical energy to replenish the battery pack charge and provides
additional vehicle range in a small lightweight package. The generator is also used as a
motor to start the range extender engine. The low mass of the range extender unit (187
lbs. or 85 kg) and compact package makes it ideal for the series hybrid drivetrain in the
Evora 414E Hybrid
All the operation and management of the range extender engine, the power management
of the batteries and motor control are controlled by Lotus’ electronic control units and
software systems. Full energy management of all the operating systems is the key to
maximizing performance and operation while minimizing energy consumption and CO2
emissions.
For everyday commuting journeys, up to 35 miles can be traveled using battery power.
The battery can be charged overnight using a conventional domestic main supply
through a socket concealed by the rear license plate. This permits the vehicle to operate
with zero tailpipe emissions. For longer journeys, exceeding the battery capacity, the
highly efficient range extender engine is used as a generator to supply the motors with
electrical power and top up the battery.
Lotus has used its own vehicle simulation tools to determine the size, capacity, power
and performance of all the components in the drivetrain system to optimize the system
operation. Overall this is far more energy efficient, weight efficient and cost effective than
fitting the vehicle with a larger and more expensive battery, which for the majority of short
journeys is a redundant weight, which increases energy requirements. With regard to the
total lifetime CO2 emissions of the vehicle, including the energy required to manufacture
and run it, the range extender solution has a lower overall CO2 footprint than a fully
electric car of comparable performance and operating range running with a larger battery.
The Package
The Lotus Evora 414E Hybrid structure is the same award-winning, versatile vehicle
architecture used on the Lotus Evora. The low volume architecture was designed with the
utmost flexibility in mind. The Evora 414E Hybrid is a perfect example of how to integrate
a compact packaged drivetrain, with excellent performance and range, while using this
underpinning. The complete chassis has remained unchanged from the Evora which
maintains the structural integrity and strength performance of the original car.
The structure progresses the Lotus ‘bonded and riveted’ technology with new and unique
extrusions and folded panels, while providing production build modularity and lower cost
repairs. The chassis has been designed for scalability so that it can be extended in width,
length and height. The strength and stiffness of the low volume VVA 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.
Driving Dynamics
The Lotus Evora 414E Hybrid offers exhilarating, all-round dynamic performance and
takes advantage of Lotus developed torque vectoring dynamics. Torque vectoring, which
is the capacity to generate different torque levels at each of the driving wheels, is
particularly suited to electric vehicles and significantly reduces the conflict between
stability and response.
A key benefit of separate motors to drive each rear wheel individually is that this
facilitates a much higher level of vehicle dynamics control. Driving the wheels with
different levels of torque can not only generate all the capabilities of a conventional ESP
system using energy regeneration as opposed to brake application, but it can also
actively drive each wheel forward at different rates, producing a turning moment at the
rear of the vehicle in addition to the steering input.
This can be used to enhance low speed maneuverability and ease of parking but can
also be used to produce a much greater level of straight line high speed stability.
Incorporating lateral sensors the system also provides stability control capabilities and
levels of steering response normally only associated with heavy and expensive rear steer
systems. This can provide automatic correction of both understeer and oversteer
characteristics. In addition, the standard method to provide high speed stability of
designing the rear wheels to toe-in is not required as the torque vectoring system
automatically provides this stability control, with toe-in increasing rolling resistance,
lowering fuel economy and increasing tire wear. Lotus‘ long history of active suspension
control provides the core capability to develop this technology and provides extraordinary
driving pleasure on the Evora 414E Hybrid.
Driver Interaction
The Evora 414E Hybrid provides less of a psychological step change for people familiar
with high performance cars compared to other electric and hybrid sports cars. The car
has a simulated paddle shift gear change offering ultra quick gear changes reminiscent
of a dual clutch transmission, while actually being single speed. This enhances the driver
interaction with the vehicle and provides a driving experience similar to current internal
combustion engine high performance sports cars. The Evora 414E Hybrid uses a column
mounted paddle shift to simulate the gear change and a synthesized engine sound
changes frequency with virtual gear selection. The drive torque is also modulated to
simulate a physical feeling of a gearshift jolt.
The virtual gearshift simulation, like a conventional gearbox, is used to change the driving
characteristics and response of the vehicle. The most significant aspect that this offers
the driver is the ability to control the vehicle deceleration by simulating engine braking
through a virtual downshift in gears. Unlike true engine braking, the Lotus system does
not dissipate the energy of the moving vehicle through internal engine friction but uses
the electric motors to regenerate the energy back into the battery. While many electric
and hybrid vehicles provide engine braking, this is generally at a fixed rate or preselected
rate. In some driving situations this can either be too aggressive, slowing the
vehicle unnecessarily, or too light, requiring additional braking application. The Lotus
system effectively allows the driver to select the appropriate level of regeneration by
simulating stepping down by one, two or even three gears. The simulation of engine
braking through both the gear noise change and the retardation of the vehicle is fully
intuitive to a driver familiar with a conventional gearbox. The simulated gearchange
capability can be selected for greater driving involvement or switched off for more relaxed
driving.
The Evora 414E Hybrid uses the Lotus Engineering and Harman International developed
HALOsonic suite of noise solutions. The first of which is Electronic Sound Synthesis. This
generates engine sounds inside the vehicle through the audio system where it provides
an exciting sports sound in line with the brand and nature of the vehicle together with a
high level of driver feedback in an intuitive manner. In addition, it also generates sound
on the outside of the vehicle through speakers mounted at the front and rear to provide a
warning to increase pedestrian safety, which is especially important for electric and
hybrid vehicles which can be difficult to hear at slower speeds.
There are four driver selectable engine sounds currently on the vehicle, two of which
have been designed to have characteristics of a multi-cylinder conventional V6 and V12
engine. There is also a futuristic sound and a combination of a conventional engine and a
futuristic sound, enhancing the brand identity of the vehicle as a step forward in electric
vehicle design.
The addition of this Lotus patented simulated gearshift concept not only provides for an
exciting and involving driving experience that customers would expect from a Lotus, but
also enhances the driver’s control of the vehicle while providing the capability for more
efficient operation through a greater use of energy regeneration.
The Design
The distinctive color scheme and ‘floating’ roof have been carefully designed to accent
the car’s electric vehicle technology while complementing the iconic lines of the Evora.
Copper, a color often associated with electrical systems, has been chosen for the car’s
exterior and interior. A contemporary satin finish paint is complemented by electrical
circuit inspired graphics that highlight the car’s key feature lines and the unique glazed
roof panel. The newly extended glazed zone integrates seamlessly with the existing
forms of the Evora while showcasing the key components behind the hybrid and electric
vehicle technology.
The signature copper theme is consistently carried throughout the car from the dramatic
seat stripes and instrument panel inserts to the copper brake callipers that nestle behind
the carbon grey forged wheels. Inside the cabin a sense of quality and richness has been
created by carefully juxtaposing the different tactile qualities intrinsic to leather, Alcantara
and metal.
