Category: Lotus Engineering

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Lotus Engineering adds lightness to a Crossover Utility Vehicle

California Air Resources Board (CARB) publishes results of Lotus Engineering’s vehicle mass reduction study on a Crossover Utility Vehicle (CUV)

  • Results show a total vehicle mass reduction of 31% (528.3 kg or 1,162 lbs.) and a $239 (£150 / €188) saving in overall vehicle cost.
  • Body structure utilises advanced materials including high-strength steels, aluminium, magnesium and composites along with high tech joining and bonding techniques.

Following on from Lotus’ successful “Phase One” study, published in 2010, which looked at the empirical and theoretical weight saving for a standard CUV, Lotus Engineering conducted further research to confirm if a lightweight and commercially feasible body structure has the potential to meet or exceed the requirements for size, luggage volume, comfort, crashworthiness and structural integrity.

Lotus Engineering’s “Phase Two” body structure design was based on the dimensions of a 2009 Toyota Venza CUV and utilised advanced materials such as high-strength steels, aluminium, magnesium and composites along with advanced joining and bonding techniques to achieve a substantial body and overall vehicle mass reduction without degrading size, practicality or performance. The body mass was reduced by 37% (311 lbs. or 141.6 kg), which contributed to a total vehicle mass reduction of 31% (1,162 lbs. or 528.3 kg) including the mass savings of other vehicle systems (interior, suspension, chassis, closures, etc.) that had previously been identified in “Phase One”.

The detailed Computer Aided Engineering (CAE) analysis undertaken indicated that a 31% mass-reduced vehicle with a 37% lighter Body-in-White (BIW) structure has the potential to meet U.S. Federal impact requirements. This includes side impact and door beam intrusion, seatbelt loading, child seat tether loadings, front and rear chassis frame load buckling stability, full frontal crash stiffness and body compatibility and frame performance under low-speed bumper impact loads as defined by the Insurance Institute for Highway Safety (IIHS). The result is a BIW design with a 20% increase in torsional stiffness over the class leading CUV.

Although the significant mass savings in the BIW design results in an increased BIW cost of $723 (£456 / €568), the overall vehicle cost is reduced through savings of $239 (£150 / €188) identified across the whole vehicle and when manufacturing and assembly costs are included in the analysis. A significant reduction in the parts count from 269 to 169, achieved by an increased level of component integration, also helped offset the increased BIW piece cost.

The background to the study

In April 2010, Lotus Engineering concluded the first phase of a study which substantiated that a reduction in vehicle mass could be achieved for medium production volume vehicles (approximately 50,000 units per year) with a 23% reduction in fuel consumption. In September 2010 the California Air Resources Board (CARB) commissioned Lotus Engineering to initiate Phase Two of the study and take a deeper look into the future of lighter, more efficient vehicles manufactured using lighter yet stronger materials.

Lotus has always been about Lightweight

When Lotus founder Colin Chapman coined the phrase “performance through light weight” he was referring to much more than mere accelerative performance. In the broader sense he meant that a lighter vehicle does everything better, including being more fuel efficient. Over the past 60-plus years, Lotus road and racing vehicles have consistently benefited from this core philosophy and Lotus has developed a strong reputation as a leader in lightweight vehicle technologies.

After decades of most manufacturers building increasingly heavy, feature-laden cars, now the very aggressive corporate average fuel economy (CAFÉ) standards increasing from a target of 35.5 mpg in 2016 to 54.5 in 2025 have all manufacturers reevaluating the virtues of mass reduction and prioritising the materials, technologies and production methods that will enable lighter, stronger and more efficient vehicles.

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Lotus Raises The Style Stakes in Monaco

Lotus Originals is the fashion arm of the legendary sports car and racing marque, and the collection is inspired by the British sense of style, heritage, innovation and rebellious spirit that goes into every on-road Lotus design.

Lotus is hailed for its engineering and thirst for competition. It is also known for style. Heroes of reality and fiction, from Jim Clark to James Bond, have outgunned their rivals from behind the wheel of a Lotus, and they looked good doing it. Partner Forza Rossa Holding, official Lotus cars dealer since 2011, recognise this and joins the Lotus family with the opening of the Monte Carlo store which carries the brand new Lotus Originals retail concept.

It’s fitting that this first franchise store be in Monaco, the scene of the first grand prix victory for a Lotus, in 1960 at the hands of Stirling Moss. His Serene Highness Prince Albert II, Monaco’s Mayor Georges Marsan and State Minister Michel Roger were joined by Lotus F1 Team’s Gerard Lopez, Eric Boullier and Romain Grosjean, Lotus Sales and Marketing Director Maurizio Parlato and Forza Rossa Holding’s President Ion Bazac at the opening of the store.

Here you will find apparel, accessories, gifts, toys, bikes and collectables that will thrill Lotus fans, and bring others into our Lotus world.

Speaking of which, we took the opportunity in Monaco to launch a special car designed for the next generation of Lotus drivers: a slightly smaller-than-usual Lotus Elan, one of Lotus’ most-beloved classics which this year celebrates its 50th anniversary. What’s more, the car is eligible for racing. The Little Big Le Mans which forms part of the Le Mans Classic race weekend, is designed for lucky young drivers aged 6-14, and this Elan is eligible for this events.

Also, 20 years after we helped win gold at Barcelona in 1992 with the revolutionary Lotus Type 108 Superbike, we are showing for the first time, a stunning hand made carbon fibre black and gold bespoke bicycle from our new collaboration with Condor Cycles Ltd.

Lotus Originals can also be found at the company’s Hethel HQ and at Norwich City Football Club’s stadium, and we’re also opening our flagship store in the heart of London in six weeks time: 4,800 sq ft of retail space on Regents Street. It will be, as it is here in Monaco, an iconic location for an iconic brand.

Maurizio Parlato, Director of Sales & Marketing, Group Lotus: “It is our mission to grow the Lotus brand internationally, to become more of a global player, and to do that we need to produce great cars, but we also want Lotus to be a lifestyle brand of its own. Our founder, Colin Chapman, understood this. He was a trendsetter in every way. He also recognised the marketing potential of motorsport better than anyone else at that time, and had an eye for detail that pervaded every aspect of his company’s presentation. Therefore, I believe he would be very excited to see what we’re doing here today – opening this first Lotus Originals franchise.”

Ion Bazac, Forza Rossa Holding President: “It is a big honour and pleasure for us to inaugurate the first Lotus Originals franchise store in such a prestigious and exclusive place like Monte Carlo, famous worldwide for its fabulous Grand Prix. With the new Lotus originals collections and accessories you will find a unique link between the past, the present and the future of the Lotus brand and its very passionate history and heroes. Lotus Originals Monte Carlo is more than a store, it is a place of meeting and dialogue between fans and their favorite brand, so that the legend, the winning heritage and dreams of Colin Chapman be more alive than ever.”

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Lotus Engineering develops Electric Drivetrain for the Rolls-Royce 102EX

Lotus Engineering, a company with over 20 years of EV and HEV experience, has been responsible for all aspects of the electric drivetrain integration for 102EX, the Rolls-Royce Phantom Experimental Electric. This includes the largest battery pack fitted to a road car, together with an innovative 7 kW induction charging system. These components and the electric drivetrain have been integrated by Lotus Engineering into the existing Phantom electrical systems, giving an efficient electrical propulsion control strategy and retaining full vehicle functionality.

Lotus Engineering has a broad expertise in vehicle design, manufacture and development. For the Phantom Experimental Electric project Lotus Engineering provided engineering services in the areas of: drivetrain layout, vehicle simulation, Computer Aided Engineering (CAE), component specification, vehicle build, control strategy, control integration, procurement, commissioning and development testing. This project highlights the technical competence in Electrical and Electronic Integration and the capability and range of consultancy services offered by Lotus Engineering.

The Phantom Experimental Electric has two electric motors to replace the 6.75 litre V12 engine. These electric motors each produce 145 kW of power to provide a total 290 kW and torque of 800 Nm giving a 0 – 100 km/h time of under eight seconds and a top speed limited to 160 km/h.

In the conversion of a Phantom into an electric vehicle a study was conducted to ensure that the optimum layout of the electric drivetrain and ancillaries was achieved with no intrusion into passenger compartment. Following an iterative design study the 71 kWh, 640 kg lithium ion battery pack was placed under the bonnet where the engine had been. The two motors, gearbox and inverters were located behind the rear seats in the original fuel tank bay, with power cables running longitudinally between the converters and the battery. This has enabled the Phantom Experimental Electric to retain its 50:50 weight distribution and characteristic Rolls-Royce driving experience.

The Rolls-Royce Phantom is a complex vehicle with many advanced electrical systems. The integration of the electric drivetrain and ancillaries with the existing vehicle control unit provided the greatest challenge for the project. To compound this the Phantom Experimental Electric features the additional complexity of a 3 mode charging system (single phase, three phase and the inductive power transfer) together with a two level driver selectable regenerative braking system.

Dr Robert Hentschel, Director of Lotus Engineering, said “The Rolls-Royce Phantom Experimental Electric is an extremely advanced vehicle. I am delighted that Rolls-Royce Motor Cars has recognised Lotus Engineering’s world class engineering capability and chosen us to be a part of this project. We have taken a great deal of pride working for such a prestigious ultra luxury brand and I believe that this project illustrates the technical competency of Lotus Engineering in Electrical and Electronic Integration and the capability to apply our expertise to a wide range of applications and types of vehicle”.

[press release from Lotus Engineering]

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Lotus Engineering wins CARB contract

2020 Toyota Venza

Lotus Engineering is delighted to announce that it has been commissioned by the Air Resources Board of California to undertake the second stage of a study investigating efficient, lightweight vehicles manufactured using lighter, stronger materials.

Lotus Engineering will conduct a detailed structural design and analysis of the prototype vehicle from an earlier study to demonstrate it meets the crashworthiness and stringent safety requirements for vehicles sold in the United States.

In April this year, Lotus Engineering concluded the first part of the study, released by the International Council on Clean Transportation in California, which recognised that a reduction in vehicle mass of 38% can be achieved for medium volume vehicles (around 50,000 units a year) with just an increase in 3% in vehicle cost and giving a 23% reduction in fuel consumption.

It is widely recognised in the automotive industry that a reduction in vehicle mass gives more efficient vehicles; with the global drive to reduce emissions, manufacturers are working hard to take mass out their cars. Lightweight vehicles have additional benefits in terms of performance, agility and cornering, (the lighter the car, the less power it needs to propel it along the road for the same performance as a heavier car).

For 62 years, Lotus has been leading the car world with ‘performance through light weight’ engineering. The strict adherence to this philosophy enabled Lotus to develop some of the finest sportscars of all time such as the Lotus Elite, Elan, Esprit from Lotus’ peerless past and the Elise, Exige and Evora from the current line up – all of which are the lightest cars in their class. But it is not just sportscars; Lotus’ consultancy division, Lotus Engineering has been applying its light weight principles behind the scenes for other car makers for years on many types of vehicles, both low volume and mass production.

This study will be led by Lotus Engineering’s Michigan, USA office with completion in April 2011. The vehicle design will use a mixture of materials best suited to its application including aluminium, magnesium, composites, high strength lightweight steel and plastics.

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Lotus Lightens a Toyota Venza

2020 Toyota Venza

Lotus Engineering has conducted a study to develop a commercially viable mass reduction strategy for mainstream passenger vehicles. This study, released by the International Council on Clean Transportation, focused on the use of lightweight materials and efficient design and demonstrated substantial mass savings. When compared with a benchmark Toyota Venza crossover utility vehicle, a 38% reduction in vehicle mass, excluding powertrain, can be achieved for only a 3% increase in component costs using engineering techniques and technologies viable for mainstream production programmes by 2020. The 2020 vehicle architecture utilises a mix of stronger and lighter weight materials, a high degree of component integration and advanced joining and assembly methodologies.

Based on U.S. Department of Energy estimates, a total vehicle mass reduction of 33% including powertrain, as demonstrated on the 2020 passenger car model, results in a 23% reduction in fuel consumption. This study highlights how automotive manufacturers can adopt the Lotus philosophy of performance through light weight.

Dr Robert Hentschel, Director of Lotus Engineering said: “Lighter vehicles are cleaner and more efficient. That philosophy has always been core to Lotus’ approach to vehicle engineering and is now more relevant than ever. Lightweight Architectures and Efficient Performance are just two of our core competencies and we are delighted to have completed this study with input from the National Highway Traffic Safety Administration and the U.S. Environmental Protection Agency to provide direction for future CO2 reductions. We believe that this approach will be commonplace in the industry for the future design of vehicles.”

The study investigated scenarios for two distinct vehicle architectures appropriate for production in 2017 and 2020. The near-term scenario is based on applying industry leading mass reducing technologies, improved materials and component integration and would be assembled using existing facilities. The mass reduction for this nearer term vehicle, excluding powertrain, is 21% with an estimated cost saving of 2%.

A benchmark Toyota Venza was disassembled, analysed and weighed to develop a bill of materials and understand component masses. In developing the two low mass concepts, Lotus Engineering employed a total vehicle mass reduction strategy utilising efficient design, component integration, materials selection, manufacturing and assembly. All key interior and exterior dimensions and volumes were retained for both models and the vehicles were packaged to accommodate key safety and structural dimensional and quality targets. The new vehicles retain the vision, sight line, comfort and occupant package of the benchmarked Toyota Venza.

Darren Somerset, Chief Executive Officer of Lotus Engineering Incorporated, Lotus’ North American engineering division which led the study, said “A highly efficient total vehicle system level architecture was achieved by developing well integrated sub-systems and components, innovative use of materials and process and the application of advanced analytical techniques. Lotus Engineering is at the forefront of the automotive industry’s drive for the reduction in CO2 and other greenhouse gas emissions and this study showcases Lotus Engineering’s expertise and outlines a clear roadmap to cost effective mass efficient vehicle technologies.”

Mass and Cost Summary

Base Toyota Venza

excluding powertrain

Lotus Engineering Design

System

Weight

(kg)

2020 Venza

2017 Venza

% Mass Reduction

% Cost Factor

% Mass Reduction

% Cost Factor
Body

383

42%

135%

15%

98%
Closures/Fenders

143

41%

76%

25%

102%
Bumpers

18.0

11%

103%

11%

103%
Thermal

9.25

0%

100%

0%

100%
Electrical

23.6

36%

96%

29%

95%
Interior

252

39%

96%

27%

97%
Lighting

9.90

0%

100%

0%

100%
Suspension/Chassis

379

43%

95%

26%

100%
Glazing

43.7

0%

100%

0%

100%
Misc.

30.1

24%

99%

24%

99%
Totals

1290

38%

103%

21%

98%

The 2020 Passenger Car Technical Details

Body

The body includes the floor and underbody, dash panel assembly, front structure, body sides and roof assembly. The baseline Toyota Venza body-in-white contained over 400 parts and the revised 2020 model reduced that part count to 211. The body-in-white materials used in the baseline Venza were 100% steel, while the 2020 model used 37% aluminium, 30% magnesium, 21% composites and 7% high strength steel. This reduces the structure mass by 42% from 382 kg to 221 kg.

The low mass 2020 body-in-white would be constructed using a low energy joining process proven on high speed trains; this process is already used on some low volume automotive applications. This low energy, low heat friction stir welding process would be used in combination with adhesive bonding, a technique already proven on Lotus production sports cars. In this instance, the robotically controlled welding and adhesive bonding process would be combined with programmable robotic fixturing, a versatile process which can be used to construct small and large vehicles using the same equipment.

Closures/Fenders

The closures include all hinged exterior elements, for example, the front and rear doors and the rear liftgate. One alternative approach included fixing the primary boot section to improve the structure, reduce masses and limit exposure to high voltage systems. A lightweight access door was provided for checking and replacing fluids.

The closures on the baseline Toyota Venza were made up of 100% steel. The low mass Venza closures/fenders would be made up of 33% magnesium, 21% plastic, 18% steel, 6% aluminium with the other 22% consisting of multiple materials. The mass savings are 41%, a reduction from 143 kg to 84 kg.

Interior

The interior systems consist of the instrument panel, seats, soft and hard trim, carpeting, climate control hardware, audio, navigation and communication electronics, vehicle control elements and restraint systems. There is a high level of component integration and electronic interfaces replace mechanical controls on the low mass model. For the 2020 model the instrument panel is eliminated replaced by driver and passenger side modules containing all key functional and safety hardware. A low mass trim panel made from a high quality aerated plastic closes out the two modules. The air conditioning module is incorporated into the console eliminating the need for close out trim panels; heated and cooled cupholders are integrated into the HVA/C module. The audio/HVA/C/Navigation touch screen contains the shifter and parking brake functions and interfaces with small electric solenoids. This eliminates conventional steel parking brake and shifter controls and cables as well as freeing up interior space.

The front seats mount to the structural sill and tunnel structure eliminating conventional seat mounting brackets (10 kg) and the need to locally reinforce the floorpan. The composite front seat structure utilises proven foam technology; the seat mass is reduced by up to 50%. The rear seat support structure is moulded into the composite floorpan eliminating the need for a separate steel support structure. The front and rear seats use a knit to shape fabric that eliminates material scrap and offers customers the opportunity to order their favourite patterns for their new vehicle. Four removable carpet modules replace the traditional full floor carpeting; this reduces mass and allows cost effective upgrading of the carpet quality. The floorpan is grained in all visible areas. The 2017 production interior mass was reduced from 250 kg to 182 kg with projected cost savings of 3%. The 2020 production interior mass was 153 kg with projected cost savings of 4%.

Chassis/Suspension

The chassis and suspension system was composed of suspension support cradles, control links, springs, shock absorbers, bushings, stabilizer bars and links, steering knuckles, brakes, steering gearbox, bearings, hydraulic systems, wheels, tires, jack and steering column.

The chassis and suspension components were downsized based on the revised vehicle curb weight, maintaining the baseline carrying capacity and incorporating the mass of the hybrid drive system.

The total vehicle curb weight reduction for the 2020 vehicle was 38%, excluding the powertrain. Based on the gross vehicle weight, which includes retaining the baseline cargo capacity of 549 kg and utilising a hybrid powertrain, the chassis and the suspension components were reduced in mass by 43%, with projected cost savings of 5%.

Front and Rear Bumpers

The materials used on the front and rear bumpers were very similar to the existing model to maintain the current level of performance. One change was to replace the front steel beam with an aluminium beam which reduced mass by 11%. The use of a magnesium beam was analysed but at the current time exceeded the allowable price factor.

Heating, Ventilation and Air Conditioning

The air conditioning system was integrated into a passenger compartment system and an engine compartment system. This section addressed the under hood components which included the compressor, condenser and related plumbing. The under hood components were investigated for technologies and mass.

The study showed a relatively small mass difference for the underhood air conditioning components based on both vehicle mass and interior volume. Because of the highly evolved nature of these components, the requirements for equivalent air conditioning performance and the lack of a clear consensus for a future automotive refrigerant, the mass and cost of the Toyota Venza compressor, condenser and associated plumbing were left unchanged for both the 2017 and 2020 models.

Glazing

The glazing of the baseline vehicle was classified into two groups: fixed and moving. The fixed glass is bonded into position using industry standard adhesives and was classified into two sub groups: wiped and non wiped.

Factors involved in making decisions about glazing materials include the level of abrasion it is likely to see during the vehicle life, the legislative requirements for light transmissibility, the legislative requirements for passenger retention and the contribution it will make to interior noise abatement.

The specific gravity of glass is 2.6 and the thickness of a windshield is usually between 4.5 mm and 5 mm, therefore the mass per square metre of 5 mm glass is approximately 13 kgs. The high mass of glass provides a strong incentive to reduce the glazed area of the body, reduce the thickness of the glass and find a suitable substitute that is lighter. Fixed glass on the side of the vehicle offers the best opportunity for mass reduction.

The mass of the baseline glazing was retained for both the 2017 and 2020 models; this was a conservative approach. It is possible that coated polycarbonate materials may become mainstream in the 2017 – 2020 timeframe for fixed applications.

Electrical/Lighting

The estimated mass savings for using thinwall cladding and copper clad aluminium wiring, as used on the 2017 model was 36% versus the baseline model. The lighting technologies section reviewed included diodes, xenon and halogen. The study also reviewed a variety of wireless technologies under development for non-transportation applications that could be used in this time period pending successful development for mobile applications.

More information
The full report, entitled ‘An Assessment of Mass Reduction Opportunities for a 2017 – 2020 Model Year Vehicle Program’ can be found at this link (pdf).

[press release from Lotus Engineering]

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Making Hybrids sound Sporty

Car & Driver magazine got a demo of the HALOsonic Sound Synthesis developed by Lotus Engineering for the Evora 414E Hybrid concept car. It allows the driver to select a range of different virtual engine configurations so that your hybrid sports car will still sound sporty even while running on electric power. Check out the video below for a full demo including virtual gear shifts.

[via Car & Driver]

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Group Lotus and Cosworth Announce Strategic Partnership

Two of Britain’s most renowned automotive names to become closely associated through a strategic partnership looking at the opportunity to develop high performance engines for Lotus road and race cars

The new partnership includes the supply by Cosworth of high performance engines based upon existing Toyota engines for future Lotus cars and the assembly by Cosworth of racing engines for all motorsport activities which are based on Toyota powertrains. The first application of these race engines will be for the V6 engine in the new Lotus Evora Cup racing car.

Dany Bahar CEO of Group Lotus commented, “The ties between Lotus and Cosworth are, of course, already historical ones but our new strategic relationship is based purely on Cosworth’s competencies, brand and race engine development capabilities. This new strategic partnership will align two of the most renowned names in the automotive world and will be of huge benefit for both organisations.”

Tim Routsis, CEO & Managing Director of Cosworth Group said, “I am delighted that the Cosworth name is once again linked to Lotus through this new strategic partnership and these new high performance engines. Our mutual history over many decades resulted in a great number of racing successes and I expect to see further triumphs not only on the racetrack but also in the competitive high performance sportscar market, where Lotus is already acknowledged as a world leader.”

[press release from Lotus]

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Geneva Preview: Lotus Evora 414E Hybrid

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.

  1. 0-60 mph/97 kph in under 4 seconds
  2. Total hybrid range of over 300 miles/483 kilometres
  3. Eco mode or Sports mode featuring realistic 7 speed paddle shift with energy recuperation
  4. HALOsonic Internal and External Electronic Sound Synthesis
  5. Torque vectoring for improved dynamic stability
  6. Integrated glass roof and engine cover and interior concept from Lotus Design

Lotus Evora 414E Hybrid

The Lotus Evora 414E Hybrid, so-named because this latest environmentally-focused technology demonstrator from Lotus Engineering produces 414 PS (306 kW) of power, 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 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 optimised for energy density, efficiency and high power demand, mounted in the centre of the vehicle for stability and safety. Additional range is provided by the Lotus Range Extender engine, an optimised 1.2 litre, 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 optimised energy recuperation.

The Evora 414E Hybrid has been designed to highlight Lotus’ innovative electric and hybrid vehicle technology without distracting from the pure sportscar 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 lbft) 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 optimised for energy density, efficiency and high power demand, with over 100 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 aluminium 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 optimised 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 light weight package. The generator is also used as a motor to start the range extender engine. The low mass of the range extender unit (85 kg) and compact package makes it ideal for the series hybrid drivetrain in the Evora 414E Hybird.

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 maximising performance and operation while minimising energy consumption and CO2 emissions.

For everyday commuting journeys, up to 35 miles can be travelled using battery power. The battery can be charged overnight using a conventional domestic mains supply through a socket concealed by the rear number 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 motor 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 optimise 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 upmost 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, whilst 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 torques 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 manoeuvrability 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 tyre 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 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 synthesised 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 colour scheme and ‘floating’ roof have been carefully designed to accent the cars electric vehicle technology whilst complementing the iconic lines of the Evora.

Copper, a colour 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 whilst 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 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.

[press release from Lotus]

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Lotus hybrid power for the PROTON Concept

The PROTON Concept car, to be unveiled at the Geneva Motor Show, showcases an advanced series hybrid drivetrain, designed and developed by Lotus Engineering.

PROTON Concept Drivetrain

Lotus Engineering, the world-renowned automotive consultancy division of Lotus Cars Limited today announces its latest series hybrid vehicle technology application in the PROTON Concept, which will be unveiled at the 80th International Geneva Motor Show. The complete hybrid drivetrain in the PROTON Concept city car has been developed by Lotus Engineering and it includes the Lotus Range Extender engine, designed specifically for series hybrid vehicles.

The PROTON Concept, a plug-in series hybrid city car, has been styled by Italdesign and will be unveiled on the Italdesign stand at the Geneva Motor Show. Lotus Engineering has designed and integrated the complete drivetrain, including the electrical drive system with single-speed transmission, which delivers low emissions, optimised performance and acceptable electric-only operating range for city use. For longer journeys, when the battery charge level falls, the 3 cylinder, 1.2 litre Lotus Range Extender engine is used to replenish the charge in the battery and provide electrical power for the drive motors. The battery can also be recharged via an AC mains domestic outlet to achieve initial electric-only operation.

Dr Robert Hentschel, Director of Lotus Engineering said: “The hybrid drivetrain of the PROTON Concept is another example of Lotus Engineering’s expertise in electrical and electronic systems and efficient performance engines. The high efficiency Lotus Range Extender engine, which we unveiled to great acclaim at the IAA Frankfurt Motor Show last year is perfectly suited for the advanced series hybrid we have created for the PROTON Concept city car. It is an exciting example of the diverse range of highly efficient total propulsion systems that Lotus Engineering continues to develop for its partners and clients.”

PROTON Holdings Berhad Group Managing Director, Dato’ Haji Syed Zainal Abidin Syed Mohd Tahir said, “Our collaboration with Lotus and Italdesign on progressive technology and design will further propel our competitiveness in the world market. Through this association, we strive to acquire and jointly develop new knowledge, skills and technologies that will ultimately benefit our customers.”

[press release from Lotus]

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Lotus Omnivore Engine interactive animation

Picture 1

While we have posted about the Lotus Omnivore engine before, all the existing information on it has been from dry technical press releases. Lotus Engineering has just released a new interactive animation that allows you to play with the various parameters of the engine and see how it alters itself to deal with various fuel mixes, loads, speeds, etc… My personal favorite is the Variable Combustion Ratio (VCR) that physically alters the volume of the combustion chamber.

Click here to play with the animation.