Bmw I3 Concept: official details, photos and specs

Article by Christian Andrei, on July 29, 2011

As expected, due to an official announcement, Bmw revealed today the i3 Concept, its all-new masterpiece that previews the vehicle designed for urban areas. The car is drive purely by electric power and embodies an intelligent form of urban transportation and commuting. The Bmw I3 Concept is powered by an electric motor found on the rear axle and capable to deliver a total output of 125 kW/170 hp and impressive torque of 250 Nm (184 lb-ft).

With these numbers, the vehicle is able to accelerate from 0 to 60 km/h (37 mph) in under four seconds and from 0 to 100 km/h (62 mph) in less than eight seconds.

The secure arrangement of the battery in the Drive module gives the vehicle a very low centre of gravity and optimum weight distribution. Regarding the interior, the Life module conjures up a feeling of space inside the car, while select materials materials lend the open and airy cabin a lounge-like character.

According to the manufacturer, the elements found on the materials lend the open and airy cabin a lounge-like character, while the naturally tanned leather of the seats creates a lounge-style ambience.

Moreover, Bmw says that the car offers a boot capacity of around 200 litres, wide-opening opposing “coach” doors, four seats and an additional functional compartment in the front – this means that the all-new i3 Concept is ready for the demands of everyday use. What is really interesting is that the I3 will offer range-extending functions, such as ECO PRO mode.

The concepts of the BMW i3 and BMW i8 are inspired by the BMW’s LifeDrive design technology. Still, the two models employ an entirely different geometric implementation.

The i3 concept for one uses the horizontal-split variant to adapt to the BMW model’s electric drive system. In this case, the Drive module supports the Life cell mounted over it.

For improved range capacity, the battery was made even bigger. After all, it serves as the driving element of the module’s fundamental design. Meanwhile, the i3 Concept battery is stored under the BMW’s flooring in order to provide space efficiency. Due to this, the car has better dynamics because the weight is distributed properly around the centre.

The BMW i3 concept battery is confined in an aluminium shell to protect against external elements and strong impacts. In case of collision, energy absorbing crash active structures are already in place.

Overall, the electric drive system is relatively more compact as compared to a typical combustion engine. It already houses the drive electronics, gear assembly and electric motor without eating up so much space under the hood. Thus, when it comes to pure electric vehicle standards, the BMW i3 Concept provides fully optimised architecture configuration from the LifeDrive technology.

The i3’s chassis is also suitable for daily city driving. In fact, it can provide an outstanding response even while driving at low gear. Likewise, the rear wheel drive’s steering function offers optimum performance since the front axle is not susceptible to any driving force. On the other hand, the torque gives an impressive traction for dynamic handling.

For its interiors, the very spacious LifeDrive module gives way to a brand-new design for the BMW i3 concept vehicle. All the Drive components were used in the new module so that the interior won’t need any more adjustments to generate more power along the rear wheels.

Comfort and convenience also wait behind the doors of the new BMW i3. The absence of B-pillars instead gives back a highly sufficient space for a more comfortable entry. The Concept car can also fit four passengers and still provide a handy space for the luggage with up to 200L boot space.

To make the most of the cabin area, the concept vehicle has strategically designed the bonnet to give extra room for other personal belongings as well as a neat little space for the charging cable.

As a whole, the BMW i3 Concept delivers more spacious interiors as compared to similar vehicles with the exact wheelbase. Add to that the full-width seat bench that provides improved functionality for city driving.

Press Release

BMW i3 Concept – dynamic, compact, emission-free

The BMW i3 Concept is an uncompromisingly sustainable vehicle designed for urban areas. Driven purely by electric power and purpose-built to meet the demands of sustainable and emission-free mobility, it embodies an intelligent form of urban transportation and commuting.
“This automotive concept uses a new architecture which showcases all of its new possibilities and potential. It is the world’s first premium electric vehicle.” (Andreas Feist, Head of vehicle project BMW i3)

The BMW i3 is a well-resolved all-round concept, with every detail conceived and optimised to fulfil its eventual purpose. Central to its design is the innovative LifeDrive architecture, the key to the BMW i3 Concept’s appeal as a light, safe and spacious car. Innovative use of materials and intelligent lightweight design not only enable the i3 Concept to travel long distances on a single charge and provide superb safety in the event of a collision, they also help give the car its excellent driving dynamics. The secure arrangement of the battery in the Drive module gives the vehicle a very low centre of gravity and optimum weight distribution. The electric motor over the rear axle – which generates output of 125 kW/170 hp and impressive torque of 250 Nm (184 lb-ft) from a standstill – and a small turning circle combine to deliver pleasingly crisp driving characteristics and give the driver a very immediate experience of the BMW i3 Concept’s lightweight design. The BMW i3 Concept accelerates from 0 to 60 km/h (37 mph) in under four seconds and from rest to 100 km/h (62 mph) in less than eight seconds. The extremely direct sensation at the wheel is expressed in outstanding agility at low speeds and during turning manoeuvres, and makes parking in tricky situations that much easier.

The Life module conjures up a feeling of space inside the car more generous than even the latest conversion vehicles can offer. Select materials lend the open and airy cabin a lounge-like character. The use of renewable raw materials is another defining characteristic of the interior, offering passengers a further means of “experiencing” the sustainability of the vehicle. Elements of the instrument panel and door panelling are visibly made from natural fibres, while the naturally tanned leather of the seats creates a lounge-style ambience. Together, these materials provide an appealing contrast to the clear, “floating” forms of the instrument panel and door elements, and lend the interior a strikingly modern feel. With the drive components located in the Drive module, there is no centre tunnel running through the passenger compartment. This allows the two front and two rear seats to be connected with each other by a continuous seat surface, which allows for ease of entry and exit via the front passenger side of the car and means you can park up close to walls, for example. With four seats, wide-opening opposing “coach” doors, boot capacity of around 200 litres and an additional functional compartment in the front, the BMW i3 Concept is neatly equipped for the demands of everyday use.

However, the electric motor developed by BMW and the optimised lightweight design of the LifeDrive architecture cannot take all the credit for imbuing the car with such efficiency and enabling it to travel such long distances on each charge. Indeed, the ability of the car to recoup energy while on the move and special range-extending functions, such as ECO PRO mode, also add miles to the clock. With ECO PRO mode activated, all the vehicle functions operate with maximum efficiency. For example, the accelerator mapping is tweaked to limit the output summoned when the driver flexes his right foot, and the climate control functions also use as little energy as possible. Added to which, sophisticated aerodynamics and slim, low rolling resistance wheels minimise resistance to the car’s forward progress and maximise its range.

Innovative connectivity functions create a seamless connection between the BMW i3 Concept and its customers’ lives outside the car. Remote functions accessible via a smartphone enable owners to find their vehicles, flag up nearby charging stations, allow battery charging and preconditioning at the touch of a button and supply information on the current status of the vehicle. Meanwhile, intelligent assistance systems ease the stress on drivers in monotonous city driving situations and allow them to arrive at their destination more safely and in a more relaxed state of mind.

The BMW i8 Concept and the fascinating approach that underpins it embody the vision of a sustainable contemporary sports car brought to life. Its innovative plug-in hybrid concept combines the modified electric drive system from the BMW i3 Concept – fitted over its front axle – with a high-performance three- cylinder combustion engine producing 164 kW (220 hp)/300 Nm (221 lb-ft) at the rear. The electric motor in the BMW i8 Concept is a full-capability unit which can also power the car on its own, if required. However, working in tandem allows the two drive systems to display their respective talents to the full, delivering the performance of a sports car but the fuel consumption of a small car.

Acceleration of 0 to 100 km/h (62 mph) in under five seconds combined with fuel consumption in the European cycle of under three litres per 100 kilometres (approx. 94 mpg imp) and average customer fuel consumption of between five and seven litres per 100 kilometres (40.4 – 56.5 mpg imp) – even when driven hard – are figures currently beyond the capability of any vehicle powered by a combustion engine of comparable performance. Thanks to its large lithium-ion battery, which can be charged from a domestic power supply, the BMW i8 Concept can travel up to 35 kilometres (approx. 20 miles) on electric power alone. A large proportion of short everyday journeys can therefore be completed with zero emissions. The car’s electric-only mode allows it to enter emissions- capped central areas of cities with access restrictions in place for petrol or diesel-powered vehicles. The i8 Concept’s efficiency rating is further enhanced by its ability to generate energy at both axles. The electric motor at the front axle recoups maximum energy every time the driver brakes, while a high-voltage alternator hooked up to the combustion engine charges the battery, if required. Added to which, the 2+2-seater offers enough space for four people, giving it a high level of everyday practicality.

The emotional design of the BMW i8 Concept ensures its qualities are clear for all to see. Its dynamic proportions give the BMW i8 Concept the appearance of surging forward before it even turns a wheel and lend visual form to its extraordinary performance. The sophisticated concept behind the upward- swivelling doors fixed to the A-pillars underlines the car’s sporting capability and opens up access to the front and rear seats at the same time.

A series of air inlets allow the air to flow through and around the vehicle to optimum effect, ensuring extremely low drag. They also add visual emphasis to these advanced aerodynamics. Airflow plays an extremely important role at the rear of the vehicle as well. Intakes behind the passenger cell and at the rear provide a cooling flow of air through the engine compartment, while outlets in the rear diffuser and the flow of air around the rear wheels ensure the car is extremely efficient in terms of lift and downforce at both axles.

The LifeDrive architecture of the BMW i8 Concept has been carefully adapted to enhance the vehicle’s sports car character, and therefore to deliver unbeatable performance and excellent driving dynamics. The motor in the front axle module and combustion engine at the rear are connected by an “energy tunnel”, which houses the high-voltage battery. This gives the car a low centre of gravity – and the dynamic benefits that come with it. The positioning of the electric motor and engine over their respective axles and the space-saving and well-balanced packaging of all components result in an optimum 50/50 weight distribution.

The weight of every component inside the BMW i8 Concept has been minimised down to the very last detail, allowing the extra weight of the electric drive system and battery to be cancelled out. The BMW i8 Concept therefore presents the ideal environment in which to sample this very special drive concept on the road. The passengers sit – in typical sports car style – in an extremely low and enclosed position inside the CFRP-constructed Life module (mounted above the Drive module).

The sporting character of the BMW i8 Concept continues into the interior. Boasting a driver-focused environment unmatched by any BMW Group vehicle before it, the BMW i8 Concept immerses the driver fully in the unique driving experience. The purpose-built driver’s position is geared squarely towards the person at the wheel and gives optimum access to all information and controls. The three-dimensional displays are crystal clear and flash up the relevant information for the driving situation at hand. The interior as a whole is defined by the functionality of a classical BMW sports car and majors on lightness and ease of use. The BMW i8 Concept is the sports car for a new generation – pure, emotional and sustainable.
BMW i thinks beyond the vehicle.

An additional range of mobility services – which can also be used independently of the cars – will be an integral component of BMW i alongside the vehicles themselves. This should allow the creation of a new, profitable area of business over the long term and attract new customers to the company’s brands. A totally new development in this area will be vehicle-independent mobility services. These will allow BMW i to offer bespoke mobility solutions representing a perfect combination of premium vehicles and premium services. The focus is on solutions which will improve usage of existing parking spaces, as well as

intelligent navigation systems with local information, intermodal route planning and premium car-sharing. In addition to service packages developed in-house, the BMW Group is pursuing cooperations with partner companies as well as strategic capital investments with providers of mobility services. BMW i Ventures was established with this purpose in mind. The company aims to expand the product portfolio of BMW i over the long term with stakes in highly innovative service providers, such as MyCityWay and ParkatmyHouse.

Purpose-built design – the LifeDrive concept.

The construction of electric vehicles has, up to now, been based on the “conversion” approach. This involves integrating electric components into vehicles originally designed to be powered by a combustion engine, as in the case of the MINI E and BMW ActiveE test cars. However, this form of automotive electrification involves making complex modifications throughout the vehicle and therefore increasing its weight considerably. That is because the electric drive components place totally different demands on a vehicle when it comes to installation space and cannot be integrated into that vehicle without adding weight and compromising interior and boot space. Conversion cars thus do not represent the best long-term response to the challenge of e-mobility.

The BMW Group engineers took a different approach, focusing squarely on the eventual usage of the BMW i vehicles in developing the LifeDrive concept. This new vehicle architecture meets the full range of technical requirements of an electric drive system (including a large battery), while keeping weight low, maximising range, creating generous levels of space, enabling supreme driving characteristics, and ensuring impressive safety for the battery and passengers alike.

In contrast to vehicles with a self-supporting body, the LifeDrive concept essentially comprises two separate, independent functional units. The Drive module integrates the vehicle’s suspension, battery, drive system, and structural and crash functions into a construction made chiefly from aluminium. Its partner, the Life module, consists primarily of a high-strength and extremely lightweight passenger cell made from carbon fibre-reinforced plastic (CFRP). The use of this high-tech material across large sections of the car ensures that the Life module is remarkably light and, in so doing, helps to achieve both impressive range and improved performance. Added to which, the car’s handling is also much enhanced, and the functional connection between the Drive module and the torsionally rigid Life module lends it a very distinctive dynamic character. The use of CFRP on this scale is unprecedented. Indeed, with the creation of its LifeDrive architecture the BMW Group has taken lightweight design, vehicle architecture and crash safety into a whole new dimension. By avoiding the need for modifications to accommodate the electric drive components, the LifeDrive architecture ensures the car is no heavier than a conversion vehicle of similar size. Intelligent lightweight design and the innovative use of materials allows the LifeDrive architecture to cancel out all the extra weight added by giving the car an electric drive train rather than a comparable combustion engine.

Another special feature of the BMW i3 Concept and BMW i8 Concept are their wheels, which are noticeably larger and narrower than those of their class rivals. Slimmer tyres generate far less drag and rolling resistance, reduce unsprung masses and, in so doing, allow the cars to travel further on a single charge and use less energy.

Lightweight and safe.

Equally impressive as the vehicle architecture’s benefits in terms of weight and handling is its performance in crash tests. Here again, the combination of the aluminium in the Drive module and the Life module’s CFRP passenger cell demonstrates just how well lightweight design and safety can go together. Like the cockpit of a Formula One car, the CFRP passenger cell provides an extremely strong survival area. Pole impacts, side-on collisions and rollover tests highlight the impressive safety-enhancing properties of this extraordinarily robust material. While metal constructions require the addition of large energy absorption zones, special deformation elements in the CFRP structure allow large amounts of energy to be absorbed in an amazingly small area. Despite the heavy and sometimes concentrated forces, the material barely sustains a dent. Together, the high-strength CFRP passenger cell and intelligent distribution of forces through the LifeDrive module lay the foundations for optimum protection for the car’s occupants and battery alike.

The LifeDrive architecture of the BMW i3 Concept.

Both the BMW i3 Concept and the BMW i8 Concept have been designed around the innovative LifeDrive architecture. However, the geometric implementation of the concept differs in the two models, having been adapted to suit their different usages. The BMW i3 Concept features a horizontal-split variant of the LifeDrive concept optimised to accommodate the car’s electric drive system. Here, the Drive module provides the solid foundations for the Life cell, which is simply mounted on top. The driving element of the Drive module’s functional design is the battery, which is made as large as possible to give the car better range. Bearing in mind the size of the BMW i3 Concept’s battery, the most space-efficient place to store it was in the car’s underfloor section. There, it occupies the whole of the module’s central section, giving the car optimum weight distribution and a low centre of gravity and therefore enhancing its dynamics. The battery is penned in by aluminium profiles, which protect it from external impacts. Crash-active structures in front and behind it provide the necessary energy absorption in the event of a front- or rear-end collision. The electric drive system is, as a whole, much more compact than a comparable combustion engine, cleverly accommodating the electric motor, gear assembly and drive electronics – in space-saving fashion – within a small area over the driven rear axle. The BMW i3 Concept therefore features the optimum LifeDrive architecture configuration for a purely electric vehicle.

The chassis of the BMW i3 Concept is also ideal for city driving. Its enviably small turning circle and direct steering responses are a recipe for outstanding agility, notably at low speeds. Rear-wheel drive allows the front axle to remain free from drive forces and therefore to carry out its steering function to optimum effect. These elements team up with the electric motor – whose impressive torque from a standstill provides exceptional traction – to produce extremely dynamic handling characteristics.

The spacious Life module of the BMW i3 Concept allows the vehicle’s interior to boast a totally new design. The integration of all the drive components within the Drive module removes the need for a centre tunnel bisecting the interior, through which power would previously have been transferred to the rear wheels. The BMW i3 Concept therefore offers significantly more interior space than other vehicles with the same wheelbase and – through solutions such as a full-width seat bench – also allows the interior to be adapted extremely effectively to the needs of urban mobility. Added to which, a pair of opposing doors and the omission of B-pillars provide a large entry area for passengers – and a generous view into the cutting-edge interior for admiring eyes. The BMW i3 Concept offers comfortable accommodation for four passengers and, with around 200 litres of boot space, room for their luggage as well. Up front, underneath what would normally be the bonnet, the Life module gives the BMW i3 Concept a separate luggage area with space for the charging cable and other items passengers would rather not carry in the passenger compartment.

The LifeDrive architecture of the BMW i8 Concept.

The BMW i8 Concept sees the LifeDrive architecture concept adapted to suit the vehicle’s sports car character – i.e. primed to deliver leading performance and sharp dynamics. This interpretation of the LifeDrive concept takes its cues from the innovative hybrid concept of the BMW i8 Concept, which links up an electric drive system at the front axle with a combustion engine over the rear wheels to lay on an unparalleled driving experience.

In a departure from the purely horizontal configuration favoured for the BMW i3 Concept, the LifeDrive architecture of its BMW i8 Concept sibling also features vertical layering in the front axle module, passenger cell and rear axle module. The drive systems powering the BMW i8 Concept are integrated into the front and rear axle modules, with the CFRP Life module providing the bridge between the two. As a plug-in hybrid, the BMW i8 Concept is not designed purely for all-electric propulsion, and therefore carries fewer battery cells than the BMW i3 Concept. These are stored in the Life module inside an energy tunnel, a structure similar to a central transmission tunnel. The front and rear axle modules therefore combine with the passenger cell and battery to form a functional unit, which adopts not only load-bearing responsibilities but also extensive crash functions. The location of the high-voltage battery in the energy tunnel gives the vehicle a low centre of gravity, and this enhances its dynamics. Together with the positioning of the motor and engine over the axles, the result is optimum 50/50 weight distribution. Intelligent lightweight design and the innovative use of materials produce extremely low unsprung and rotating masses, which is good news for the car’s driving dynamics, acceleration, range and fuel economy. All in all, the BMW i8 Concept offers the ideal environment in which to experience the special drive concept and distinctive sports car character of the BMW i8 Concept on the road.

The BMW i8 Concept’s axles are designed to deliver optimum handling properties, in keeping with the car’s sporting profile. The multi-link front axle provides the ideal geometric platform for an extremely flat and aerodynamically efficient silhouette. The front axle construction is also designed explicitly to handle the twin demands of the steering and drive system. It eliminates any drive forces which may otherwise affect the steering, ensuring optimum handling in every situation.

In the CFRP Life module passengers sit low down and enclosed – in classical sports car style – between the motor and engine. Between them runs the energy tunnel that intersects the interior. Swivelling doors fixed to the A-pillars provide large openings that allow access to both front and rear seats. Four seats make the BMW i8 Concept a practical everyday vehicle that brings together the full array of positive BMW attributes.

Intelligent lightweight design.

Systematic lightweight design is a particularly important element of electrically- powered vehicles. An electric drive system (incl. battery) tips the scales at up to 200 kg heavier than a comparable combustion engine and full tank of fuel. And high vehicle weight is a major factor – alongside battery capacity –in restricting how far an electric car can travel on a single charge. As well as increasing such a vehicle’s range, lower vehicle weight is also a ticket to noticeably improved performance. After all, a lightweight vehicle accelerates faster, is more agile through corners and brakes to a standstill more quickly. Lightweight design therefore paves the way for greater driving pleasure, agility and safety. In addition, lower accelerated mass means that energy-absorbing crash structures can be scaled back – and that, in turn, saves weight. The aim of the development engineers was therefore to achieve the electrification/hybridisation of the vehicles without adding weight. Alongside the innovative LifeDrive architecture, other aspects central to the BMW Group’s success in cancelling out the extra weight of the electric components were systematic lightweight design and the innovative use of materials.

“The LifeDrive concept avoids the additional weight involved in making the necessary modifications to conversion concepts. At the same time, in both vehicles we’ve been able to cancel out all of the extra kilos added by the electric motor(s) through the innovative use of materials and intelligent lightweight design.” (Bernhard Dressler, Responsible for bodywork and equipment
at project i)

The various components within a vehicle’s structure have to deal with an extremely wide range of demands, which can only be addressed to full effect by a variety of construction methods. For each component, the BMW Group engineers therefore select the material to fit its usage profile and the demands placed on it, so that battery weight is no longer an issue. In order to meet the engineers’ ambitious aims, every component has been rigorously developed, examined and, if necessary, modified to optimise its functional effectiveness and minimise weight. Designing the components specifically for their particular purpose ensures the vehicles work as well and weigh as little as possible. CFRP plays a major role in reducing weight. The extensive use of this material – e.g. in the Life module of the BMW i3 Concept and BMW i8 Concept – is unprecedented in volume vehicle production. CFRP is at least as strong as steel, but roughly 50 per cent lighter. By comparison, aluminium would save “only” 30 per cent in weight over steel. All of which makes CFRP the lightest material available for vehicle body construction which does not compromise safety.

As well as “conventional” CFRP components made from resinated carbon fibre weave, in some areas the BMW i8 Concept also contains specially woven CFRP structures known as “braided profiles”. Here, CFRP preforms are woven like a sock over a mould. This allows much greater design freedom, and fewer joints are required. Flush-fitting connections also make the profiles extremely strong. The braided profiles are therefore used in areas – such as the door sills, doors and A-pillars – in which greater strength is required, not least in the event of a collision. The special manufacturing process involved makes it extremely easy to optimise wall thickness (by adjusting the diameter of the mould). Much more complex forms can also be achieved without bonding or the use of connecting pieces and, most importantly, produce far fewer waste cuttings. Lower material usage also reduces the energy requirement.

Two vehicles, two drive concepts.

BMW i stands for a new concept in sustainable mobility and a new approach to vehicle drive system design. The BMW i3 Concept and the BMW i8 Concept, with their highly innovative and efficient drive systems, demonstrate how future mobility can be both sustainable and dynamic. The BMW i3 Concept and BMW i8 Concept are two entirely different vehicles, and this is reflected in their different drive concepts. In both cases the design and configuration of the drive systems are dictated by the individual character of the vehicle and its intended area of application. While the BMW i3 Concept is an all-electric vehicle and therefore optimally equipped for operation around town, the plug-in hybrid BMW i8 Concept combines its electric motor with an internal combustion engine to deliver a high level of performance. The common link between the two vehicles is their electric motor, which marks a move away from exclusive reliance on an internal combustion engine. These cars are “born electric”, and define a whole new concept in drive technology in their segment.

All-electric – the BMW i3 Concept.

The electric motor of the BMW i3 Concept is designed primarily for operation in an urban environment. Already tested in a pre-production version in the BMW ActiveE, the version of this permanently excited hybrid synchronous motor which will be used in the BMW i3 Concept has undergone further optimisation in terms of weight and driveability. It develops 125 kW/170 hp, with peak torque of 250 Nm (184 lb-ft). Typically of an electric motor, maximum torque is developed from standstill, in contrast to an internal combustion engine where torque increases with engine rpm. This makes the BMW i3 Concept highly agile and provides impressive acceleration. The BMW i3 Concept accomplishes 0-60 km/h (37 mph) in under four seconds and 0-100 km/h (62 mph) in under eight seconds.

At the same time the abundant torque is delivered over a very large rpm range, resulting in very smooth power delivery. The single-speed gearbox provides optimal power transmission to the rear wheels and accelerates the BMW i3 Concept to an electronically governed 150 km/h (93 mph) without the loss of power typically associated with having to shift gears. The speed governor cuts in at this point in the interests of efficiency: going even faster would result in very high energy consumption, which would unnecessarily restrict the driving range. The motor is located directly above the drive axle, for optimal and typical BMW rear-wheel-drive handling characteristics.

But impressive, instantaneous, response is not the only distinctive aspect about the driving experience in the BMW i3 Concept. Another is the dual accelerator/decelerator function of the accelerator pedal. After the driver eases up on the accelerator, the electric motor acts as a generator, converting the kinetic energy into electricity which is then fed back into the battery. Energy recuperation generates a braking effect which makes a significant contribution to vehicle deceleration. Around town, approximately 75 per cent of all braking operations can be performed in this way, i.e. without using the brake pedal at all. Intensive use of this energy recuperation function of the electric motor can increase the driving range by up to 20 per cent. Only when the driver’s braking request exceeds a given level is the conventional brake system of the BMW i3 Concept engaged as well.

A coasting facility makes this unique “single-pedal control” of acceleration and braking using just the accelerator even more user-friendly. The BMW i3 Concept features a distinct “neutral” position of the accelerator pedal, i.e. rather than switching straight to recuperation when the driver eases off the pedal, the electric motor’s zero torque control keeps the drive train disconnected as long as the pedal is in this position. The vehicle now coasts without consuming power, driven by its own kinetic energy. Used as part of a proactive driving style, this coasting mode is a very user-friendly way of increasing the driving range even further.

Compact and powerful – the electric motor.

The electric motor of the BMW i3 Concept not only offers attractive driveability, it also has a very high power-to-size ratio. This is partly explained by the fact that electric motors typically achieve over 90 per cent energy efficiency. This means that a smaller electric motor can produce the same power output as a larger internal combustion engine. Due to its compact size, the electric motor used in the BMW i3 Concept can be optimally integrated into the vehicle architecture. The permanently excited hybrid synchronous electric motor and the power

electronics of the BMW i3 Concept were developed entirely in-house, and boast very high efficiency, optimised power delivery and compact design. As mentioned, the innovative nature of the electric motor is particularly evident in the favourable power-to-size ratio. As a result of continuous development and refinement, the space requirements of the electric motor used in the

BMW i3 Concept have been reduced by 40 per cent compared with the motor used in the MINI E. This compact drive unit is mounted over the rear axle, together with the power electronics, transmission and differential, causing no loss of interior space.

The power needed to drive the vehicle and to operate all other vehicle functions is supplied by specially developed lithium-ion battery cells. The BMW i3 Concept’s battery system has undergone detailed optimisation which significantly reduces the extent to which external factors can influence the vehicle’s power and driving range. An integrated liquid cooling system keeps the battery at its optimal operating temperature at all times, which helps to significantly boost the performance and life expectancy of the cells. The climate/heating system cools the fluid circulating in the battery housing via a heat exchanger.

If necessary, in winter, this fluid can also be heated in order to bring the battery up to its optimal operating temperature of around 20 degrees Celsius. These precautions ensure that power and torque remain constant throughout most of the battery’s charge range and make the system significantly less sensitive to extreme external temperatures. The battery can be fully recharged in six hours at a standard power socket. If a high-speed charger is used, an 80 per cent charge can be achieved in just one hour.

Range Extender increases the driving range.

As the MINI E field tests showed, a driving range of 120 to 150 kilometres (74 to 93 miles) was sufficient to meet 90 per cent of the mobility requirements of the pilot users. However, some customers want a longer driving range, or want their vehicle to be as flexible as possible. The BMW i3 Concept therefore offers an optional Range Extender, the REx, which allows the electric driving range to be increased. REx, a small, very smooth-running and quiet petrol engine, drives a generator which maintains the battery charge level and therefore extends the range of the electric motor. As soon as the battery charge reaches a critical level, REx supplies the necessary energy to get the driver the rest of the way to his destination. In a sense, therefore, the Range Extender is like having a reserve fuel can on board.

The very compact size of the electric motor used in the BMW i3 Concept means there is room left over to accommodate REx and its attached generator over the rear axle, alongside the drive components. The petrol engine complies with the SULEV standard, currently the strictest emissions standard for internal combustion engines. To reduce fuel consumption to a minimum, REx also features such functions as Automatic Start-Stop and other intelligent operating strategies.


Topics: bmw, bmw i3, concept

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