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Solar roof: additional energy without fuel consumption


Solardach: Zusätzliche Energie ohne Kraftstoffverbrauch



BMW Vision EfficientDynamics

Experience driving pleasure and reduce fuel consumption and exhaust emission levels - BMW EfficientDynamics makes both possible at the same time. BMW's unique development strategy has now been taken one stage further:

../../JPG/BMW/bmw00118.JPG, photo by bmw 2008with the concept study BMW Vision EfficientDynamics, the German premium automobile manufacturer presents a vehicle in which a diesel engine and BMW ActiveHybrid Technology combine to provide increased driving dynamics with a total output of 165 kW and an acceleration rate of 0 to 100 km/h in 8.9 seconds, as well as fuel consumption reduced to just 6.5 litres per 100 kilometres in the EU test cycle and a CO2 emission level of 172 grams per kilometre. The combination of current BMW diesel engine expertise and pioneering hybrid technology reflects the unique potential of the development strategy BMW EfficientDynamics. With model-specific innovations, BMW achieves the best possible relation between sheer driving pleasure and economy in all vehicle segments. The concept study BMW Vision EfficientDynamics is based on the Sports Activity Vehicle BMW X5 which already occupies a leading position in its segment in terms of both driving dynamics and efficiency. This is due to the use of technologies selected for this specific model which were developed as part of the BMW EfficientDynamics program. The concept car BMW Vision EfficientDynamics adheres to this consistent strategy with further innovations which are harmoniously integrated with one another. This applies particularly to the combination of a 4-cylinder diesel engine with a Mild Hybrid concept, ensuring a new dimension of efficiency in this vehicle segment. What is more, the generator supports the combustion engine with an output of 15 kW and a maximum torque of 210 Nm: this is the basis for being able to realise the drive characteristics typical of the BMW X5 with a 4-cylinder diesel engine. For the purposes of efficiency optimisation, Mild Hybrid and the 4-cylinder diesel engine complement each other just as well as in the BMW Concept X6 ActiveHybrid with its combination of a Full Hybrid concept and an 8-cylinder petrol engine. With these differing approaches, BMW demonstrates the large breadth of potential hybrid applications. This also shows that in the field of hybrid technology, solutions tailored to specific models and concepts help achieve maximum efficiency in all output categories and vehicle segments. BMW Vision EfficientDynamics has at its disposal a large number of measures for promoting efficiency which already form part of the standard fittings of new BMW models, as well as others which are potential options for future use. Each individual innovation presented in the concept car BMW Vision EfficientDynamics is capable of achieving a further increase in efficiency which is relevant to the customer - to a degree of technological expense and effort which is realistic for serial production vehicles. This is also in keeping with the character of technologies developed as part of the BMW EfficientDynamics program both in the past and in the future. They are successively being integrated in more and more model series, each one in a specific configuration to suit the model in question. In this way, the impact of these innovations in enhancing efficiency is able to grow steadily and become increasingly widespread. With the overall package of innovations used in the concept car BMW Vision EfficientDynamics, the already outstanding efficiency of the standard BMW X5 is taken to the limits of what is feasible in this segment, regardless of today's customer acceptance of a large vehicle with a small engine and its costs. The study combines the supremacy, comfort and extensive space provision of a large SAV with levels of fuel consumption and exhaust emissions which would otherwise only be familiar among conventional vehicles of the compact class. This shows that with this highly advanced degree of optimisation, any reduction of fuel consumption and exhaust emission levels going beyond this would require a disproportionate increase in technological effort and expense. For reasons of cost, such an imbalance would work against the realization of such measures in serial production vehicles.

Innovative combination: BMW diesel engine and BMW ActiveHybrid.

../../JPG/BMW/bmw00119.JPG, photo by bmw 2008 The combustion engine of this study - a 2.0 litre 4-cylinder diesel with Variable Twin Turbo, common rail direct injection of the third generation and all-aluminium gearbox housing - was developed as part of BMW EfficientDynamics. The state-of-the-art engine delivers 150 kW/204 bhp. With a maximum torque of 400 Nm from 2,000 rpm, it provides pulling power at the level of a 6-cylinder diesel with a much larger capacity. In spite of this, the new 2.0 litre engine has one of the lowest levels of fuel consumption in the world for a diesel engine. Its unsurpassed efficiency is also due to the BMW EfficientDynamics measures in the environment of the engine, including Brake Energy Regeneration, needs-oriented control of ancillary units and the Auto Start/Stop Function. This intelligent energy management is supplemented in the concept car BMW Vision EfficientDynamics by BMW ActiveHybrid Technology, resulting in a further increase of both dynamic performance and efficiency. A generator integrated in the gear casing with an output of 15 kW and a maximum torque of 210 Nm supports the combustion engine in producing a dynamic drive torque, also combining with a lithium-ion battery at the rear of the vehicle to efficiently supply power for numerous electrical consumers. The Mild Hybrid concept means that the vehicle has a direct increase in dynamic performance during acceleration: its total output is 165 kW. What is more, the generator is able to produce electrical power with a high degree of efficiency and without direct conversion of primary energy due to Brake Energy Regeneration. With its high performance and storage capacity, the lithium-ion battery allows ancillary units to be operated on electrical power at a level which goes far beyond what is currently possible in serial production vehicles. The possibilities of this concept extend to powering the air conditioning compression, the electric coolant pump and an electrical steering system. For these extended functions, a 120 volt vehicle power system was designed which operates parallel to the conventional 12 volt network in the BMW Vision EfficientDynamics study. The intensified production and use of electrical energy takes the strain off the combustion engine so that the latter can operate even more economically and at the same time generate an even higher level of driving dynamics. BMW Vision EfficientDynamics also shows what other advances will be possible in future in connection with BMW EfficientDynamics. The concept study has a solar roof with photovoltaic units which generate electrical energy while the vehicle is at a standstill. This energy can either be stored or used immediately. In particular, this energy produced in a CO2-neutral manner is available to pre-heat the gear oil. Inefficient warm-up phases are thus significantly shortened. In addition, it is possible to operate ventilation, air conditioning and entertainment systems permanently even when the vehicle is stationary, without having to draw on the reserves of the vehicle batteries. In order to optimise aerodynamics, the concept car BMW Vision EfficientDynamics not only has active air intake flaps which are also available in serial production vehicles and a chassis with lowered suspension, it is also fitted with completely newly developed wheels. The design of the light alloy rims is designed to achieve an intensive reduction of aerodynamic drag.

Unique: a large SAV with 165 kW and an average fuel consumption of 6.5 litres per 100 kilometres.

The harmonious overall concept on which the concept study BMW Vision EfficientDynamics is based is just as impressive as the variety of individual measures it includes. All components have been carefully harmonised with one another and go together to form a fascinating, trend-setting whole. Based on the successful Sports Activity Vehicle BMW X5, a concept study has been created which demonstrates the unique potential of BMW EfficientDynamics on a whole new scale. The big SAV model provides generous and versatile space. Its superior chassis technology and the intelligent all-wheel drive system BMW xDrive ensure it offers outstanding agility and supreme driving properties over all terrains. By combining BMW ActiveHybrid Technology with a highly efficient 4-cylinder diesel engine which has an outstanding output of 150 kW/204 bhp, these qualities can be realised at a level of fuel consumption and exhaust emissions which is exemplary. The concept car BMW Vision EfficientDynamics fulfils the requirements of a large SAV in the premium segment in terms of driving pleasure, space and comfort. With a total output of 165 kW, an acceleration rate of 0-100 km/h in 8.9 seconds, an average fuel consumption in the EU test cycle of 6.5 litres per 100 kilometres and a CO2 emissions level of 172 grams per kilometre, it offers a balance between driving dynamics and economy which is unique in this vehicle category.

BMW ActiveHybrid generates more electrical energy from less fuel.

../../JPG/BMW/bmw00120.JPG, photo by bmw 2008The technology applied in the concept car BMW Vision EfficientDynamics aims to support the combustion engine in generating dynamic performance as well as operating as many vehicle functions as possible electrically by producing the electrical power required by means of Brake Energy Regeneration. Both functions are performed by the generator, compactly and safely integrated in the transmission casing, with an output of 15 kW and a maximum torque of 210 Nm. Under load it provides additional drive torque which results in a perceptibly more spontaneous response in start-up situations. This further intensifies the power delivery of the diesel engine with Variable Twin Turbo - which is already quick in response. The support provided by the generator gives the 4-cylinder engine the drive characteristics appropriate to a BMW X5. During trailing throttle and braking phases, the generator feeds the electrical power it produces to the lithium-ion battery via the high-power electronic system system, which is likewise fully integrated. This form of Brake Energy Regeneration represents a consistent further development of the principle which has already been applied to BMW serial production models. Brake Energy Regeneration generates electricity for the vehicle power supply whenever it is available at no cost and does not impair driving dynamics. The generator integrated in the transmission casing provides a significantly more efficient form of power generation than a conventional generator which takes energy directly from the combustion engine and thus diminishes its efficiency. In terms of its own efficiency, too, BMW ActiveHybrid Technology is superior to a conventional generator: the energy efficiency achieved by means of Brake Energy Regeneration is about ten times greater than with a conventional generator.

Intelligent energy management with lithium-ion battery, AGM battery and two vehicle power systems.

The additional energy can only be used if it can be fed to a battery in varying rhythms and is available there as dictated by needs, regardless of individual driving style. Furthermore, the storage capacity has to be at a high level so that lengthier distances without trailing throttle and braking phases can be dealt with without a supply shortfall occurring. In serial production vehicles which are fitted with Brake Energy Regeneration, BMW uses AGM (Absorbent Glass Matt) batteries for this reason since they can cope with frequent and irregular charge and discharge cycles without loss of power. Another step forward in development is the use of lithium-ion batteries in this vehicle. In many other areas of application - for example in mobile phones and laptops - this type of battery has long demonstrated its high storage capacity and cycle resilience. The lithium-ion battery used in the concept car BMW Vision EfficientDynamics shows a perspective for the use of this technology under the particular demanding conditions which apply to a motor vehicle. The lithium-ion battery is placed directly adjacent to the AGM starter battery under the luggage compartment cover of the Sports Activity Vehicle, as is appropriate to the overall package. The two batteries occupy approximately equal space here. In order to ensure that energy management is as needs-oriented and efficient as possible, the concept car BMW Vision EfficientDynamics is fitted with two parallel vehicle power systems. In addition to the conventional 12 volt system supplied by the AGM starter battery there is also an innovative 120 volt system which is fed by electrical power from the generator and supplies electrical consumers from the lithium-ion battery.

High storage capacity increases efficiency and comfort.

The lithium-ion battery used in the concept study BMW Vision EfficientDynamics is able to supply a particularly large number of electrical consumers with power via the 120 volt electrical system. This high-voltage network is also the requirement for the connection of especially high-power electrical power systems. In contrast to a conventional vehicle power system, for example, this includes the possibility of directly powering air conditioning compressors. In existing BMW serial production models, the functions which can be electrically powered already range from ventilation and air conditioning to lighting, entertainment, navigation and communication systems, servomotors for steering, the coolant pump and the driving dynamics system such as Electronic Damper Control, optionally available as part of the optional Adaptive Drive system in the BMW X5. The stable and reliable supply of energy to all the electrically powered vehicle functions in the concept vehicle BMW Vision EfficientDynamics is guaranteed regardless of the driving situation. This also means that the Auto/Start Stop Function in conjunction with ActiveHybrid Technology can be used more frequently than in current serial production vehicles and without any loss of comfort. When stopping at a junction, at a set of traffic lights or in a tailback, the combustion engine is automatically switched off so as to avoid inefficient idling phases. As soon as the driver releases the brake pedal and activates the accelerator pedal to set off again, the engine is automatically restarted. The functions which are no longer linked to the generator in the concept study BMW Vision EfficientDynamics can continue to be operated during the interim stop phases. The energy required for this is permanently supplied by the high-capacity lithium-ion battery. In particular, the continued operation of the ventilation and air conditioning systems contributes to the optimisation of comfort as the desired interior temperature can be maintained at a constant level. All other comfort functions can also be used permanently while the engine is switched off.

Innovative 8-speed automatic transmission: higher shift dynamics, greater efficiency.

The hybrid components, the generator and - for the first time - the high-power electronic system, are integrated in and mounted directly on the transmission casing which is extended in length by around 4 centimetres for this reason. The transmission itself has also been completely newly developed. The new 8-speed automatic transmission, developed jointly by BMW and ZF Getriebe GmbH and presented in the concept car BMW Vision EfficientDynamics for the first time, is soon to be used in serial production for conventional BMW vehicles. It is characterised by outstanding shift dynamics and a level of efficiency which remains unsurpassed for automatic transmission systems. In the concept car BMW Vision EfficientDynamics the new, extremely fast and efficient 8-speed automatic transmission also ensures that there is a further increase in driving dynamics and economy in the transmission of propulsion power. The conception which provides for eight drive positions allows a broad spread of gears so as to enhance efficiency. It means that the optimum drive position can be selected even more precisely for each situation than with the familiar 6-speed automatic transmission systems - from the point of view of dynamic performance or efficiency. Gear shifting is even faster and more precise. The new transmission is fitted with a sophisticated electronic control system and its unsurpassed response and shift speed is highly impressive, setting sporty standards. An electronic gear finding system allows one or more drive positions to be skipped so as to select the ideal drive position directly. With gently flowing shift transitions and only slight engine speed jumps, the new 8-speed automatic transmission system also offers maximum ride comfort as well as increasing dynamic performance. The new 8-speed automatic transmission also makes an additional contribution to the efficiency of the concept car. A clear and practically measurable fuel consumption reduction is achieved not only by the broad spread of gears and reduced inner loses but also the direct connection of the transmission to the engine. Its converter clutch is closed immediately after the vehicle sets off. This means that torque-converter slip - which impairs power output - is reduced to a minimum. What is more, the direct engine connection supports the vehicle's capacity for dynamic acceleration.

Powerful basis for efficient dynamics: BMW diesel engines.

It is with good reason that the diesel versions of the BMW X5 are especially popular not only in Germany but also in many other markets. Over the course of about two and half decades, BMW has gained experience in the construction of diesel vehicles and made use of its outstanding engine expertise in developing highly attractive representatives of this drive form. The model program ranges from the outstandingly economical BMW 118d with 4-cylinder diesel engine and 105 kW/143 bhp to the BMW 520d (4-cylinder, 130 kW/177 bhp) - with an unequalled level of efficiency in its class - through to the top class models, the BMW 635d Coupé and BMW 635d Convertible (in-line 6-cylinder diesel, 210 kW/286 bhp) and the luxury sedan BMW 745d (8-cylinder diesel, 242 kW/330 bhp). All BMW diesel models are characterised by a balance between driving dynamics and economy which is unequalled by any other vehicle in the respective competitive field. In particular it is the combination of Variable Twin Turbo charging and common rail direct injection of the third generation which ensures such an excellent balance between engine output and fuel consumption. The unique charging system consists of two turbochargers of different sizes whose interaction is regulated by a powerful electronic control system. At lower engine speeds, the smaller turbocharger is initially active. Due to its low moment of inertia it responds to slight movements of the accelerator pedal. As engine speed increase the larger turbocharger comes into play as well. In this way, the excellent pulling power of the engine sets in just above idling speed and is maintained across a broad load range. The efficiency of the engine is further optimised by the common rail system by which piezo injectors convey the fuel into the combustion chambers under very high pressure and in precisely measured quantities.

Engine of superlatives: BMW 4-cylinder diesel with Variable Twin Turbo.

Variable Twin Turbo Technology will be applied to a BMW 4-cylinder diesel engine for the first time in the model year 2008. The new 2.0 litre engine with Variable Twin Turbo - also an all-aluminium power unit with common rail direct injection of the third generation responsible for the fuel supply - delivers an output of 150 kW/204 bhp at an engine speed of 4,400 rpm. The unique supercharging system makes the new 4-cylinder the world's first all-aluminium diesel engine with a specific output of over 100 bhp per litre of capacity. Its maximum torque of 400 Nm is equally impressive, already available at 2,000 rpm. With its lively revving and the vehemence of its power delivery, the new 4-cylinder clearly leads the field when compared to other engines of its kind. Its pulling power reaches the level of higher-capacity 6-cylinder diesel engines. The new 4-cylinder diesel engine not only sets standards in terms of output but also as regards efficiency. The impressive pulling power is combined with an unusually low weight thanks to the engine's all-aluminium construction as well as a unique level of economy in relation to output. Its fuel consumption and exhaust emission levels significantly undercuts less powerful diesel engines among the competition. This outstanding efficiency is the second no less impressive characteristic of the engine. The key factor here is the common rail injection system of the third generation. In the 4-cylinder diesel with Variable Twin Turbo, the diesel fuel - fed via a shared line - is injected by piezo injectors into the combustion chambers under especially high pressure. For the first time, an injection pressure of 2,000 bar is reached. This enables a high degree of precision in the determining the quantity of fuel and efficient combustion. Since the fuel is injected in up to three portions per combustion cycle, the flame spreads relatively gently which mainly benefits the diesel engine's running smoothness. With this sum of qualities, the new 4-cylinder diesel with Variable Twin Turbo is ideally suited to becoming the central pillar in a concept with which to further develop the potential of BMW EfficientDynamics technology. Due to its efficiency it fulfils all the requirements for achieving uniquely low fuel consumption and exhaust emission levels. Thanks to its power and with the support of the generator, it fulfils the high demands made of an SAV model in the premium segment. What is more, this modern engine perfectly complements the other innovations for the reduction of fuel consumption and exhaust emissions presented in the concept car BMW Vision EfficientDynamics. This especially applies to the study's ActiveHybrid module. In developing the hybrid components, BMW is seeking to realise applications which are individually tailored to the specific model or concept in question. BMW ActiveHybrid is based on a modular principle which allows the optimum components for different vehicle concepts, according to the strategy "Best of Hybrid". In the concept car BMW Vision EfficientDynamics, the 4-cylinder diesel engine and the generator complement each other ideally as Mild Hybrid components - just like the 8-cylinder petrol engine and the Full Hybrid concept in the BMW Concept X6 ActiveHybrid presented in 2007. This breadth of potential hybrid applications is in keeping with the principle of BMW EfficientDynamics of developing solutions for all vehicle segments and output categories which are specific to the concept and vehicle in question. BMW develops hybrid components in co-operation with Daimler with each party having equal status. The aim of this co-operation is to develop and test components or hybrid drive forms for luxury performance segment vehicles. The integration of hybrid components in the various vehicles is undertaken by each manufacturer separately, taking into account the specific brand qualities of each.

Solar roof: additional energy without fuel consumption.

Intelligent energy management even goes beyond vehicle operation in the concept car BMW Vision EfficientDynamics. The study has a solar roof with photovoltaic units which generate electricity even when the vehicle is at a standstill. This can either be stored or used immediately. The solar roof thus serves as an additional source of energy for the vehicle power system which is independent of the engine. Powerful solar cells over a surface area of some 1.0 square metres generate a maximum output of one kilowatt hour for consumers both inside and outside the vehicle. This energy is especially available for pre-heating the gear oil. Inefficient warm-up phases can thus be significantly reduced. What is more, direct energy supply is available during standstill for such functions as ventilation, operating a cool box, audio equipment or mobile phone chargers as well as for charging the vehicle battery. This reduces the need to convert fuel into electrical energy. Although this function takes effect while the vehicle is stationary and no measurable fuel consumption benefit from it can be ascertained in the test cycle, there is an obvious added value relevant to the customer: increased comfort from energy which is produced in a CO2-neutral way.

Aero-rims: fascinating design, optimised aerodynamics.

The body height of the vehicle is reduced by means of specific chassis modifications as compared to the serial production model. For the further optimisation of aerodynamics, new 19-inch light alloy rims with reduced ventilation effects were specially developed for the concept study BMW Vision EfficientDynamics. The aerodynamically optimised shaping of its spokes reduces resistance at the wheel's axis of rotation. The impact of this directionally bound rim design specifically geared towards aerodynamics and thus to the efficiency of the vehicle is considerable. When travelling at high speeds, a vehicle fitted with the aerodynamic rim has to produce one kilowatt of engine output less at a speed of 160 km/h than the equivalent vehicle with conventional wheels, for example. This effect is not included in the calculation of the standardised average fuel consumption either, but it is certainly noticeable when driving.

Clear accentuations in design: progress made visible in the detail.

BMW Vision EfficientDynamics is based conceptually in terms of design on the BMW X5. The appearance of the successful Sports Activity Vehicle is preserved. Certain details reflect functional modifications which serve to optimise the vehicle's aerodynamics, for example. The fact that the concept study is largely identical to the serial production vehicle symbolises the aspiration of the concept car to demonstrate the potential of BMW EfficientDynamics technology within an existing vehicle segment. The concept study BMW Vision EfficientDynamics provides feedback on the kind of increase in efficiency which is feasible in an SAV model of the premium segment without having to impose limitations on the characteristic properties of this model in terms of driving experience, comfort and space. Finished in exclusive Mineral White, the vehicle has roof rails in Aluminium Satin. The plastic protective trim at the lower edge of the body is in Titanium Silver - distinct from the serial production model. The ActiveHybrid components in the engine and luggage compartments are labelled with the relevant designations. The "EfficientDynamics - ActiveHybrid" lettering on the lower section of the doors also shows the Sports Activity Vehicle to be an especially economical and low-emission concept.

A perspective for the future: BMW Vision EfficientDynamics.

../../JPG/BMW/bmw00270.JPG, photo by bmw 2008 With the application of innovative hybrid technology in combination with a 4-cylinder diesel engine, the concept car BMW Vision EfficientDynamics is set firmly within the development strategy BMW EfficientDynamics. As in the past, new technologies in the future for the reduction of fuel consumption and exhaust emissions will be applied in a combination which is adapted specifically to the model in question to provide increased driving dynamics and fuel efficiency. The aim is to develop concepts for all model series which provide maximum driving pleasure with as little fuel consumption as possible. In the field of hybrid applications, too, BMW opts for solutions adapted specifically to particular concepts and models. The Mild Hybrid concept put forward in the concept car BMW Vision EfficientDynamics thus offers just as promising a perspective as the Full Hybrid concept of the BMW Concept X6 ActiveHybrid. The great variety of innovations and their intelligent combination with efficiency-enhancing measures already applied in serial production vehicles is what distinguishes the character of the concept car BMW Vision EfficientDynamics. It demonstrates what might be feasible in the field of fuel consumption and CO2 reduction when the highest level of development expertise and innovative concepts are applied. Each individual innovation presented in this concept car can achieve a further increase in efficiency which is relevant to the customer. The sum total of these effects is illustrated by the concept car BMW Vision EfficientDynamics, at the same time demonstrating the limits of what is feasible in the vehicle segment of the BMW X5. It shows clearly that in a vehicle which is already highly optimised, a disproportionate degree of technological expense and effort would be required to achieve even an even greater increase in efficiency. This also shows just how significant an advance has already been achieved by means of BMW EfficientDynamics in reducing fuel consumption and exhaust emission levels.


Media Information
February 2008



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