The first purpose-built, plug-in hybrid sports car from BMW has gone on sale powered by engines exclusively produced at BMW’s Hams Hall engine manufacturing facility, near Birmingham.
The BMW i8 is a brand-new contemporary, sustainability-focused sports car. It is the first BMW production vehicle to be powered by a three-cylinder engine and together with BMW eDrive technology is able to combine the dynamics of a high-performance sports car with the fuel efficiencies of a small car. Demand in the UK is high and already the BMW i8 has sold out for more than a year.
A brand-new, unique production facility has been developed at the Hams Hall plant for the world-wide production of the new three-cylinder BMW TwinPower Turbo technology petrol engines – the first of a new generation of engines to be built at the plant.
Transport Minister Baroness Kramer said: “The British-made engine for this ground-breaking car demonstrates that the UK automotive industry is at the forefront of the production of high-quality, low emission car technology. As our recent commitment to invest £500m in ultra-low emission vehicle design, production and adoption shows, we want the UK to be a world leader in the global transition to ultra-low emission motoring.”
Plant director, Nick Spencer, said: “Our plant is going through a huge transformation, and we are excited to see the first of our brand-new engine assembly facilities ramping up production. The new three-cylinder petrol engines will enable the BMW i8 plug-in hybrid sports car to set new standards for dynamic performance in combination with industry-leading fuel efficiency and low carbon emission levels. With the exclusive supply of these engines coming from the Hams Hall plant, we are proud to be contributing to this innovative new sports car.”
Each engine is built by a small team of people, all of whom previously worked at the plant and have been specifically recruited and trained to work on the new engines. Two technical apprentices who spent the final year of their training programme working on the development of the new production area are now placed in full-time technical jobs within the new team having successfully completed their apprenticeships.
Front electric motor with battery pack in backbone
Former apprentice James Law said: “My apprenticeship was an ideal combination of academic study, through which I achieved higher qualifications, along with practical, invaluable work placements. It has been a fantastic opportunity to see this new engine manufacturing facility being installed and I’m thrilled to have successfully completed my apprenticeship and to be working in such an interesting, technical role within the new team.”
The Hams Hall plant already has a sustained 13-year history of manufacturing over 3.5 million small, fuel efficient and low emission engines since its official opening in 2001. Over 400,000 engines were produced during 2013 representing around 16 per cent of all engine production in the UK. Ramping up production of this new facility forms the first part of an ongoing multi-million pound development programme at the Hams Hall site which will continue into next year.
Rear-mid mounted three-cylinder petrol engine
BMW i8: Three-cylinder petrol engine with BMW TwinPower Turbo technology combined with BMW eDrive technology in the form of a hybrid synchronous electric motor; engine with a displacement of 1.5 litres, output of 231PS and maximum torque of 320Nm; power sent to the rear wheels via a six-speed automatic gearbox; electric motor with an output of 131PS and maximum torque of 250Nm; power channelled through the front wheels via a two-stage automatic transmission; lithium-ion high-voltage battery with direct refrigerant cooling and gross capacity of 7.1 kWh.
The BMW i8 embodies a revolutionary, future-focused interpretation of the driving pleasure for which BMW is renowned. It was purpose-designed as a plug-in hybrid sports car offering agile performance and outstanding efficiency. An exceptionally lightweight and aerodynamically optimised body – including a passenger cell made from carbon-fibre-reinforced plastic (CFRP) – plus advanced BMW eDrive drive system technology, a compact, highly turbocharged 1.5-litre petrol engine with BMW TwinPower Turbo technology and intelligent energy management all come together to create an overall concept that represents a new landmark in the Efficient Dynamics development strategy. The BMW i8 blends the performance of a top-end sports car with the sort of fuel economy and emissions usually associated with compact models. It is based, moreover, around a vehicle architecture that creates the perfect platform for thrillingly agile handling, thanks to an ultra-low centre of gravity and almost exactly 50:50 weight distribution. The BMW i8 boasts supremely precise driving dynamics and superb steering feel, giving the driver outstanding command of the vehicle even when exploring the limits of its performance.
The three-cylinder combustion engine in the BMW i8 develops 170kW/231PS and drives the rear wheels, while the 96kW/131PS electric motor draws its energy from a lithium-ion battery, which can be charged from a conventional domestic power socket, and sends its power to the front axle. This bespoke plug-in hybrid system, developed and produced by the BMW Group, enables a range of up to 37 kilometres (23 miles) in the EU test cycle and a top speed of 120km/h (75mph) on electric power alone, coupled with a “glued-to-the-road” all-wheel driving experience headlined by powerful acceleration and a dynamically-biased distribution of power through keenly taken corners. The more powerful of the two power sources drives the rear wheels and uses the electric boost from the hybrid system to deliver hallmark BMW driving pleasure while at the same time offering groundbreaking levels of efficiency. The sprint from 0 to 100 km/h (62 mph) takes just 4.4 seconds, yet combined fuel consumption – as calculated in the EU test cycle for plug-in hybrid vehicles – stands at 2.1 litres per 100 kilometres (approx. 135 mpg imp) plus 11.9 kWh of electricity. This equates to CO2 emissions of 49 grams per kilometre.
The actual fuel economy in everyday driving provides further impressive proof of the BMW i8’s outstanding efficiency. Depending on the user’s charging habits and the distances driven, it is capable of returning fuel consumption figures that are almost unheard of for a sports car. The typical driving requirements of commuter traffic can be met with average fuel consumption of less than five litres per 100 kilometres (over 56.5 mpg imp) when utilising the two drive units. If the daily commute is combined with longer sections of motorway and country driving – on weekend trips for instance – the intelligent powertrain management in the BMW i8 is capable of keeping consumption below the seven litres per 100 kilometres mark (40.4 mpg imp). And even when it’s just being used for long-distance holiday driving, fuel consumption still averages below eight litres per 100 kilometres (35.3 mpg imp). Overall, the plug-in hybrid’s fuel consumption figures are around 50 per cent lower than conventionally powered models in the sports car segment under virtually all operating conditions.
For maximum driving pleasure and efficiency: BMW TwinPower Turbo engine and BMW eDrive.
The plug-in hybrid drive system of the BMW i8, which comprises a BMW TwinPower Turbo engine combined with BMW eDrive technology, offers the best of both worlds: excellent potential for improved efficiency and exciting, sporty driving characteristics. The BMW Group has developed not only the internal combustion engine and electric motor in-house but also the power electronics and the battery. This ensures that all these components offer high product and quality standards, underpinned by the outstanding capabilities of the BMW Group in the field of powertrain research and development.
The revolutionary character of the BMW i8 is emphasised by a further innovation: the use of an internal combustion engine which is making its debut in this model. The BMW i8 is the first BMW production model to be powered by a three-cylinder petrol engine. This highly turbocharged unit is equipped with latest-generation BMW TwinPower Turbo technology. It is exceptionally compact and extracts maximum power of 170 kW/231 hp from its 1.5-litre displacement. The resulting specific output of 113kW/154PS per litre of displacement is on a par with high-performance sports car engines and is the highest of any engine produced by the BMW Group.
The new three-cylinder engine derives its typical characteristics from BMW’s six-cylinder in-line engines, to which it is closely related and which are noted for their eager power delivery, revving ability and refinement. The three-cylinder’s BMW TwinPower Turbo technology comprises a high-performance turbocharging system and direct petrol injection with high-precision injectors positioned between the valves, along with VALVETRONIC throttle-less load control, which improves efficiency and response thanks to seamlessly variable valve lift control. Like a straight-six engine, the three-cylinder unit is free of first and second-order inertial forces. The low rolling moment, a typical feature of a three-cylinder design, is further reduced by a balancer shaft, while a multi-stage damper integrated in the automatic transmission ensures very smooth and refined running at low rpm. BMW TwinPower Turbo technology and low internal friction improve both fuel efficiency and torque characteristics. Accelerator response is sharp and the three-cylinder unit quickly reaches its maximum torque of 320Nm. It also makes its mark by producing a decidedly sporty soundtrack. Both this and the engine’s hearty appetite for revs stem from the design characteristics it shares in common with the six-cylinder in-line unit featuring BMW TwinPower Turbo technology.
The car’s second power source is a hybrid synchronous electric motor specially developed and produced by the BMW Group for the BMW i8. The motor develops maximum power of 96kW/131PS and instantly produces its maximum torque of 250Nm from standstill. Besides the instantaneous response typically generated by electric motors when pulling away, power continues to be developed into the higher load ranges. Credit for the linear power delivery, which extends right up to the high end of the rpm range, goes to a special motor design developed exclusively for BMW i. BMW eDrive technology refines and improves on the principle of the permanently excited synchronous motor with a special arrangement and dimensions for the torque-producing components. This has the effect of generating a “reluctance torque” in addition to the drive torque from the permanent magnets resulting from the rotor’s magnetic asymmetry. The upshot of this is that the electric motor can continue to supply plenty of torque at high revs, unlike other motor designs. The hybrid synchronous motor owes its name to this blend of torque-producing properties stemming from two different types of motor.
As well as providing a power boost to assist the petrol engine during acceleration, the electric motor can also power the vehicle by itself. Top speed is then 120km/h (approx. 75mph). The BMW i8 has a maximum driving range in this emission-free, virtually soundless, all-electric mode of up to 37 kilometres (23 miles) as measured on the EU test cycle. The motor derives its energy from the lithium-ion battery which is centrally mounted underneath the floor of the vehicle. This model-specific version of the high-voltage battery was developed and produced by the BMW Group. It features an evaporative cooling system, offers a gross energy capacity of 7.1 kilowatt hours and can be recharged from a conventional household power socket, at a BMW i Wallbox or at a public charging station. The battery was designed by the BMW Group and built to last for the life of the car. Customers receive a warranty for the battery spanning eight years or 100,000 kilometres (approx. 62,000 miles).
Sports car also displays maximum efficiency when it comes to operating costs.
The vehicle concept and drive system technology of the BMW i8 help it earn top marks for efficiency. The low fuel consumption of the plug-in hybrid sports car brings with it not only impressively low emissions but also significantly reduced running costs.
The process for calculating the average fuel consumption of plug-in hybrid vehicles in the EU test cycle also takes into account the use of the available energy capacity in a fully charged battery. All of which allows the BMW i8 to boast unrivalled economy given its performance potential; the test cycle fuel consumption comes in at 2.1 litres per 100 kilometres (134.5 mpg imp). This figure is based on a driving profile where the high-voltage battery’s capacity is initially used for all-electric driving, before switching to hybrid mode when energy is recuperated to recharge the battery, allowing further sections of the journey to be covered solely on electric power. This profile uses up 11.9 kWh of electricity and 2.1 litres (0.5 gallons) of fuel to complete the 100 kilometres (62 miles). Assuming electricity charges of 0.25 euros per kWh and a fuel price of around 1.50 euros per litre, this results in energy costs of some 6.00 euros per 100 kilometres. This is equivalent to the price of around four litres (0.9 gallons) of premium unleaded petrol.
The pioneering powertrain technology at the heart of the BMW i8 allows customers to benefit from the tax incentives offered in many countries for ultra-low-emission vehicles, especially for electric and hybrid cars. The reliability of the electrical drive system components and their low maintenance requirements minimise the amount of servicing needed. The vehicle concept of the BMW i8 has a favourable impact on its insurance rating too. Any damage to the exterior bodyshell, such as occurs in around 90 per cent of all accidents, can be rectified with relatively little effort and expense by replacing plastic components. Overall, the repair costs following a collision are similar to those for conventional BMW models. This is reflected in the BMW i8’s German insurance group rating, which is low for a high-powered sports car in this segment (group 30 for fully comprehensive protection).
All-new sports car driving sensation rooted in hybrid-specific all-wheel drive and intelligent energy management.
The rear wheels of the BMW i8 are driven by the petrol engine via a six-speed automatic transmission, while the front wheels receive their power from the electric motor via a two-stage automatic transmission. This, together with the maximum output of 266kW/362PS and peak torque of 320Nm at the rear wheels and 250Nm at the front, provides all-wheel-drive performance which is as dynamic as it is efficient. The BMW i8’s intelligent powertrain control system ensures perfect coordination of both power sources. The variable power-sharing between the internal combustion engine and the electric motor makes the driver aware of the sporty temperament of the BMW i8 at all times, while at the same time maximising the energy efficiency of the overall system. Using the two power sources in unison enables the car to sprint to 100km/h (62mph) from stationary in 4.4 seconds. The BMW i8 has an electronically controlled top speed of 250km/h (155mph), which can be reached and maintained when the vehicle operates solely on the petrol engine.
Variable front-rear power splitting in line with changing driving conditions makes for excitingly dynamic cornering. On entering the corner, the power split is biased towards the rear wheels to improve turning precision. For more vigorous acceleration out of the corner, the powertrain controller returns to the default split as soon as the steering angle becomes smaller again.
The BMW i8’s vehicle concept and powertrain control system mark it out as a progressive, revolutionary sports car. It always achieves the optimal balance between dynamic performance and efficiency, whatever the driving situation. In order to do this, the interaction between combustion engine and electric motor is governed by the intelligent energy management system aboard the BMW i8. A bespoke display and control concept and the link-up between the driver, car and outside world provided by BMW ConnectedDrive bolster the efficiency-enhancing effect of the energy management system. At the same time, they make the targeted management of energy flows in the BMW i8 something the driver can experience in considerable depth.
The high-voltage battery can be recharged via the electric motor with energy recuperated on the overrun. Recovery of energy during braking and overrun phases takes place particularly frequently while driving in SPORT mode. The high-voltage starter-generator, responsible for starting the combustion engine, can also be used as a generator to charge the battery, the necessary power being provided by the BMW TwinPower Turbo engine. These various processes help to ensure that the BMW i8 always has sufficient energy on board to power the electric drive system. The all-electric driving range is sufficient to cover most urban driving requirements. Out of town, the BMW i8 delivers impressively sporty performance extremely efficiently, thanks to the electric motor’s power-boosting support for the petrol engine. With such versatility, the BMW i8 belongs to a new generation of sports car which unites sensational performance with cutting-edge efficiency – to enhance both driving pleasure and the sense for sustainability.
The standard-fitted Navigation System Professional links up with a version of the proactive drivetrain management system likewise specially developed for the BMW i8. When the route guidance function is activated, the drivetrain management is configured to ensure the electric motor is employed as extensively as possible and as wisely as possible from an efficiency point of view. The system analyses the route in full and sets up the drivetrain management to run on purely electric power over low-speed sections of the journey in particular. In so doing it also ensures, for example, that the battery has sufficient capacity for driving in all-electric mode when approaching the journey’s end.
Five driving modes allow drivers to adjust efficiency and dynamic performance as desired – at the touch of a button.
The BMW i8 affords the driver unusually wide scope for adjusting the drive settings and vehicle setup in order to adapt the driving experience to his or her individual preferences. As well as the electronic gear selector for the automatic transmission, the driver can also use the Driving Experience Control switch – a familiar feature of the latest BMW models – for this purpose. This gives the driver a total of five operating modes to choose from: COMFORT mode, SPORT mode and ECO PRO mode, with the additional option of switching to all-electric driving in COMFORT and ECO PRO mode by pressing the eDrive button. The Driving Experience Control switch on the centre console gives drivers a choice of two vehicle setups. On starting, COMFORT mode is activated, which offers a balance between sporty performance and fuel efficiency, with unrestricted access to all convenience functions. The everyday driving range of the BMW i8 on a full fuel tank and with a fully charged battery in COMFORT mode is up to 600 kilometres (approx. 375 miles), as measured in the EU test cycle. Alternatively, at the touch of a button, ECO PRO mode can be engaged, which, on the BMW i8 as on other models, fosters an efficiency-optimised driving style. The powertrain controller coordinates the cooperation between the petrol engine and the electric motor for maximum fuel economy. At the same time, ECO PRO mode also programs electrical convenience functions such as the air conditioning, seat heating and heated mirrors to operate at minimum power consumption – but without compromising safety.
SPORT mode offers sequential manual gear selection and at the same time switches to a very sporty vehicle setup. With the SPORT setting activated, the engine and electric motor deliver extra-sharp performance, accelerator response is faster and the power boost from the electric motor is maximised. And to keep the battery topped up, SPORT mode also activates maximum energy recuperation during overrun and braking, ensuring that the BMW i8 is able to perform to the very best of its sporting abilities at all times. If the battery is being recharged using the car’s kinetic energy, the electric motor’s generator function switches to a more powerful setting. At the same time, gear change times are shortened and an extra-sporty setting is selected for the standard-fitted Dynamic Damper Control and the Electric Power Steering.
When the eDrive button is pressed, the vehicle will switch to the electric motor as its sole power source. Only if the battery charge drops below a given level or the driver suddenly wishes to drive at full throttle (kickdown) does the internal combustion engine cut in automatically.
A bespoke display and control concept that further intensifies the driving experience brings the sporty and progressive character of the BMW i8 even further to the fore. The iDrive Controller, gear selector and driving function buttons on the centre console are all positioned in the classic BMW arrangement. The instrument cluster in the BMW i8 takes the form of a fully digital multifunctional instrument display. Three-dimensional graphics are used to present the current road speed in digital form, information on the vehicle and powertrain status, as well as feedback from the driver assistance systems, Check Control messages and detailed route instructions from the navigation system. The electric range is permanently displayed too, along with the fuel gauge for the petrol engine.
The specially adapted version of the fully digital instrument display fitted in the BMW i8 shows the car’s speed and driving status information in a format and colour selected to suit the driving mode currently engaged. Traditional, orange-coloured circular dials are used for the speed and rpm readouts in SPORT mode. In COMFORT mode a blue “powermeter” display replaces the rev counter to keep the driver up to speed on what the electric motor is up to, while ECO PRO mode adds an efficiency display, which encourages drivers to maximise fuel efficiency through their use of the accelerator.
The high-end chassis and suspension technology of the BMW i8 is based on a double-wishbone front axle and a five-link rear axle, whose aluminium components have been specially designed and manufactured in order to optimise both their weight and strength. Not only does the double-wishbone axle with split lower link level enable high levels of lateral acceleration and ensure excellent straight-line stability, this design principle also has the effect of minimising transmission of any bumps in the road to the steering. The kinematics of both the front wheel suspension and the five-link axle at the rear have been geared to superb handling dynamics. What’s more, the elastokinematics have been precision-tuned for the vehicle to strike an ideal balance between insulation from tyre roar and satisfying the high demands placed on its dynamic performance abilities.
The Electric Power Steering offers easy manoeuvring in town and typical sports car-style high-speed steering precision. Another distinguishing feature is that it requires remarkably little energy too. The steering wheel developed especially for the BMW i8 bears the hallmark BMW i design traits, such as the coloured rim inlay and the BMW emblem encircled by a blue ring. It is furthermore the lightest steering wheel available in any BMW Group model and includes both multifunction buttons and shift paddles for changing gear manually as standard, thereby capturing the sporty and sustainable character of the BMW i8 to perfection.
Also standard is Dynamic Damper Control: the electronically controlled dampers endow the vehicle with sharper agility without any loss of ride comfort. The dampers’ characteristics change according to the selected driving mode to deliver the desired vehicle dynamics.
The DSC (Dynamic Stability Control) system includes the Anti-lock Braking System (ABS), Cornering Brake Control (CBC), Dynamic Brake Control (DBC), Brake Assist, Brake Standby, Brake Drying function, Start-Off Assistant, Fading Compensation, Active Differential Brake (ADB-x), Driving dynamic impellent torque pre-control, E-Traction, as well as the push button-activated Dynamic Traction Control (DTC) mode.
The brake system on the BMW i8 was purpose developed for the road-hugging hybrid powertrain and delivers superlative performance with outstanding stopping abilities. The perforated brake discs and black painted brake callipers, meanwhile, simply ooze quality and sporty flair.
The car’s standard-fit 20-inch forged aluminium wheels sport a bi-colour finish, along with an aerodynamically optimised, lightweight design, plus mixed-sized tyres measuring 195/50 R20 at the front and 215/45 R20 at the rear. Two further light-alloy wheel designs are available as alternatives to the standard specification, both shod with mixed-sized tyres measuring 215/45 R20 for the front and 245/40 R20 for the rear wheels. The slender profile of both wheels and tyres together with their large diameter helps to further hone the aerodynamic properties at the same time as ensuring great cornering dynamics and supreme traction. Finally, the tyres’ low rolling resistance further reduces the BMW i8’s power consumption.
Lightweight design, maximised occupant protection: Body and safety
The BMW i8 has its own version of the LifeDrive architecture developed for BMW i that gives it a unique range of tools for combining intelligent lightweight design and safety – to the highest standard in each case. The horizontally split LifeDrive architecture consists of two separate, independent modules. The combustion engine and electric motor, battery pack, power electronics, chassis components, and structure and crash functions are arranged together in the aluminium Drive module, while the central element of the Life module is the 2+2-seater’s carbon-fibre-reinforced plastic (CFRP) passenger cell. The vehicle structure and materials employed in the i8 represent a pioneering example of automotive construction and reinforce the position of the BMW i8 as an exceptionally progressive model in the sports car segment.
CFRP is the lightest available material that can be used in the construction of a car body without compromising on safety. One of the stand-out characteristics of this high-tech material is its hugely impressive torsional rigidity, yet it also carries 50 per cent less weight than steel and is 30 per cent lighter than aluminium. The LifeDrive architecture and high proportion of CFRP and aluminium in the car’s construction allow a previously unprecedented degree of weight saving. The intelligent lightweight design is therefore able to compensate for the additional weight of the plug-in hybrid drive system and the high-voltage battery. The kerb weight of the BMW i8 stands at 1,485 kilograms, and the LifeDrive architecture also has a positive effect on how this weight is distributed. The battery unit is positioned low down in a central position, helping to give the car a low centre of gravity and enhance safety accordingly. Indeed, the centre of gravity of the BMW i8 is less than 460 millimetres from the ground, making it lower than any other current BMW Group model. And this, like the car’s almost exact 50:50 weight distribution, ensures excellent handling properties.
The principle of intelligent lightweight design was applied to the rest of the car’s components, too. The intelligent construction of the magnesium instrument panel support brings a weight saving of around 30 per cent compared with the BMW 6 Series, for example. In addition, the high structural rigidity of the magnesium support structure gives it a strengthening effect which allows the number of components to be reduced, thereby lowering weight by a further 10 per cent. Innovative foam plastic technology used in the air conditioning ducts cuts their weight by 60 per cent compared with a conventional solution, while also improving acoustics thanks to its sound-absorbing properties. The fact that the power electronics and electric motor are directly connected reduces the amount of wiring required, while partial use of aluminium wiring enables a further reduction in weight.
The BMW i8 is also the world’s first volume-produced vehicle to be equipped with chemically hardened thin glass. This innovative technology, so far used mainly in smartphone manufacturing, lends the material impressive strength. The partition between the passenger compartment and boot of the BMW i8 consists of two layers of chemically hardened glass, each of which is just 0.7 millimetres thick, with acoustic sheeting sandwiched in between. In addition to excellent acoustic properties, a further advantage of this solution is a weight saving of around 50 per cent compared with conventional laminated glass.
The outer skin of the BMW i8 is made of thermoplastic polymers and is likewise manufactured at BMW Plant Leipzig. Apart from being half the weight of sheet steel, the plastic material provides corrosion-free surface protection that is produced using a low-energy process and is resistant to minor damage, too.
The LifeDrive architecture allows exceptional levels of freedom when it comes to body design. In the case of the BMW i8, the result is an appearance that faithfully reflects the car’s sporting characteristics, its innovative premium character and its ground-breaking technology. The impressive structural strength of the CFRP passenger cell allows particularly large door apertures, which in turn ensure comfortable access, even to the rear seats of the BMW i8. The distinctive doors, which open forwards and upwards like wings, are composed of a CFRP inner structure and an aluminium outer skin. This construction is 50 per cent lighter than a conventional door design.
In its dry, resin-free state, CFRP can be worked almost like a textile, and as such allows a high degree of flexibility in how it is shaped. The composite only gains its rigid, final form after the resin injected into the lattice has hardened. This makes it at least as durable as steel, but it is much more lightweight. The high tear resistance along the length of the fibres also allows CFRP components to be given a high-strength design by following their direction of loading. To this end, the fibres are arranged within the component according to the load processes it is subject to. By overlaying the fibre arrangements, components can also be strengthened against load in several different directions. In this way, the component design can be made significantly more efficient and effective than is possible with any other material that is equally durable in all directions – such as metal. This, in turn, allows further reductions in terms of both material use and weight, leading to another new wave of savings potential. The lower accelerated mass in the event of a crash means that energy-absorbing structures can be scaled back, cutting the weight of the vehicle.
The development of the LifeDrive architecture and the version of it used for the BMW i8 incorporated the latest findings from safety and accident research and the requirements of international crash test procedures. The high-strength passenger compartment teams up with the intelligent distribution of forces within the LifeDrive module to provide the cornerstones for optimum occupant protection. The extremely rigid material used for the passenger cell and the crash-activated aluminium structures at the front and rear end of the Drive module maintain an intact survival space for passengers even in a structurally debilitating offset front crash.
Impressive rigidity, combined with its ability to absorb an enormous amount of energy, makes CFRP extremely damage-tolerant. Even at high impact speeds it displays barely any deformation. As in a Formula One cockpit, this exceptionally stiff material provides an extremely strong survival space. Less body deformation occurs compared with comparable steel bodies. Furthermore, the doors can be opened without any problem and the interior remains largely free of intrusions. Rescue scenarios were worked through and checked as part of the development process. In standard cutting tests, the process of rescuing occupants from a BMW i8 involved in an accident was, in various scenarios, even more straightforward than that for conventional vehicles. That is because body components made from CFRP are lighter and can be more easily cut than high-strength steels, for example.
The impressive safety characteristics of CFRP also come to the fore in side impact scenarios. Despite the heavy, in some cases concentrated forces, the material barely sustains a dent, and passengers enjoy unbeatable protection. All of which makes CFRP perfectly suited for use in a vehicle’s flanks, where every centimetre of undamaged interior is invaluable. However, there are limits to what CFRP can endure. If the forces applied go beyond the limits of the material’s strength, the composite of fibres breaks up into its individual components in a controlled process, absorbing energy as it does so.
The occupant protection concept is rounded off by standard safety equipment – including electronically controlled restraint systems – of the same high standard in terms of scope and effectiveness as that featured in vehicles from all the BMW Group’s brands. Front airbags and side airbags integrated into the seat backrests, plus head/curtain airbags for both rows of seats, are all fitted as standard, as are three-point inertia-reel seatbelts including belt tensioners and belt force limiters for all seats.
The crash-activated aluminium structures in the front and rear sections of the vehicle provide unbeatable safety for the Drive module. In a front or rear-end collision, these absorb a large proportion of the energy generated. The battery, meanwhile, is mounted centrally in the underbody section of the car to give it the best possible degree of protection. Statistically, this is the area that absorbs the least energy in the event of a crash, and the vehicle is subject to barely any deformation here as a result.
The high-voltage system is designed to cope with accidents beyond the legal requirements and includes safeguards with a multi-redundant design to ensure the high-voltage battery’s safe reaction even in situations such as these. A series of tests conducted by the renowned DEKRA E-Mobility Competence Center were extremely extensive – ranging from how a car might catch fire, how the flames might spread and what would be required to extinguish the fire, to the pollution caused by run-off of the water used for fighting the fire. The experts concluded that electric and hybrid cars with lithium-ion drive system batteries are just as safe as vehicles with conventional drive systems. To ensure maximum safety in such a crash scenario, the high-voltage battery is disconnected from the high-voltage system and the connected components discharged as soon as the passenger restraint systems are triggered.
Tests by vehicle insurers and BMW Accident Research show that accidents primarily result in minor damage. In around 90 per cent of all recorded accidents involving conventional vehicles, the damage sustained is to the outer skin. The BMW i8 takes account of this and is equipped with screw-on/clip-on plastic panelling all around. Minor bumps are absorbed without leaving dents, as usually occurs with metal parts, and damage to the paint does not lead to corrosion. If a section of the external skin needs to be replaced, this can be carried out quickly and economically.
Thanks to innovative repair methods, which also encompass the CFRP components, the sum total of the accident repair costs for all the different cases of damage is similar to that for conventionally powered BMW models.
As a result, the BMW i8 has a comparatively low insurance rating in Germany (group 30 for fully comprehensive).
The slim headlights of the BMW i8 team up with the BMW kidney grille to form a horizontal unit emphasising the car’s width. The plug-in hybrid sports car is fitted as standard with powerful and energy-efficient full-LED headlights. In their lower section, the light sources are framed by a U-shaped bar into which are integrated the daytime driving lights, sidelights and direction indicators. The intricately designed rear light clusters also feature the U-shape typical of BMW i cars. All of the lights on the BMW i8 are LEDs as standard. The optional LED headlights with extended features also include a specific light distribution mode for a notably improved light range when driving on motorways and cross-country routes at speeds over 120km/h (75mph).
Before the end of 2014, the BMW i8 will become the world’s first series-produced vehicle to be made available with innovative laser headlights as an option. These generate a pure-white, extremely bright light that is pleasant to the eye by carefully converting the beams emitted by tiny laser diodes using a fluorescent phosphorous material inside the headlight. The laser diodes are ten times smaller than conventional light-emitting diodes, helping to save space in the headlight unit and also reduce weight. What’s more, the reflector’s surface area can be made far smaller compared to LED headlights, and measures less than 3 centimetres in height compared to 9 centimetres previously.
Laser light is monochromatic, which means that the light waves all have the same length (colour). They also have a constant phase difference. As a result, laser lighting can produce a near-parallel beam with impressive luminance, which gives it an intensity ten times brighter than that of conventional light sources. The beam can also be adjusted extremely precisely. The optional laser boost light furthermore produces a high-beam range of up to 600 metres, thereby doubling the already impressive range of the sophisticated LED high-beam headlight. The camera-based, digital High Beam Assistant reliably prevents both oncoming traffic and vehicles travelling ahead from being dazzled. Apart from all this, the laser lighting system is even more efficient too, meaning that energy consumption can be reduced by more than a third even compared to LED headlights, which are already very efficient themselves; laser light generates approximately 170 lumens (photometric unit of light output) per watt, whereas LED lighting produces around 100 lumens per watt.
The pedestrian alert sound that has previously been required by law for electrically powered vehicles in certain markets will be offered as an option worldwide. To ensure that pedestrians are able to detect the vehicle’s presence more easily when driving at low speeds purely on electric power, a distinctive sound is generated that mimics the noise made by a turbine. This pedestrian alert sound is active at speeds of up to 30 km/h (approx. 18 mph) in order to amplify the vehicle’s barely audible road/tyre and wind noise when travelling at this speed.