The concept study based on a BMW X5 – even as a serial production model extremely efficient and dynamic – shows the unique potential of technology developed as part of the BMW EfficientDynamics program. It combines BMW’s superior diesel expertise with the innovative BMW ActiveHybrid Technology. A further increase in efficiency is achieved by means of BMW EfficientDynamics measures in the environment of the combustion engine by optimising energy flow and aerodynamics.
By intelligently combining a combustion engine and a generator as part of a Mild Hybrid concept, dynamic performance and efficiency are increased to an equal degree. With the extensive deployment of measures which are in some cases ready for serial production and were in some cases specially developed for this study, there is maximum utilisation of the potential of BMW EfficientDynamics for the reduction of fuel consumption and CO2 emission levels up to the limits of what is feasible within the BMW X5 vehicle segment. At the same time, the study clearly shows that any additional increase in efficiency over and above the highly efficient BMW vehicles already available today can only be achieved by means of an exponential increase in effort and expense.
With an average fuel consumption of 6.5 litres per 100 kilometres in the EU test cycle and a CO2 emission level of 172 grams per kilometre, BMW Vision EfficientDynamics is by far the most efficient vehicle of its size in the competitive environment of the BMW X models. The significant reduction of fuel consumption and exhaust emission levels is realised having to forego BMW’s characteristic driving dynamics. In addition to acceleration (0-100 km/h in 8.9 seconds), comfort and versatility are also at the level of a large SAV – but in conjunction with the fuel consumption and CO2 emission levels of conventional vehicles in the compact class.
Technology
The 2.0 litre 4-cylinder diesel engine with Variable Twin Turbo, common rail injection of the third generation and all-aluminium gearbox housing delivers 150 kW/204 bhp and generates a maximum torque of 400 Nm between 2,000 and 2,250 rpm. It is the first diesel in the world with a specific power output of over 100 bhp per litre of capacity.
BMW ActiveHybrid is based on a modular principle which allows the integration of the best possible components in differing concepts, according to the “Best of Hybrid” strategy. The components used in the BMW Vision EfficientDynamics study – Mild Hybrid and 4-cylinder diesel – harmonise just as perfectly as the combination of Full Hybrid and the 8-cylinder petrol engine in the BMW Concept X6 ActiveHybrid.
The innovative hybrid system of the concept study BMW Vision EfficientDynamics reflects the most sophisticated stage of development of intelligent energy management in the vehicle to date. In the Mild Hybrid concept, the generator contributes to vehicle acceleration with 15 kW and a maximum torque of 210 Nm. The total output of the vehicle is 165 kW. The hybrid technology thus increases the dynamic potential of the 4-cylinder diesel engine in way which is in keeping with the character of the BMW X5, as well as enabling the combination of a small engine with a large vehicle in the first place. What is more, the generator produces electricity to supply the power consumers in the vehicle by means of Brake Energy Regeneration. This minimises the direct conversion of fuel into electrical energy and maximises the drive torque available for conversion into driving dynamics.
Power generation: the compact generator, integrated in the gearbox housing, replaces a conventional generator powered directly by the engine. Electrical energy is produced by Brake Energy Regeneration with a unique degree of efficiency without impairing the drive torque of the engine. The high-power electronic system – for the first time flange-mounted directly onto the gearbox – allows a compact design which has never been possible before, as well as a sound arrangement of the hybrid components.
Battery: a high-performance, package-appropriate lithium-ion battery integrated in the luggage compartment supplies the vehicle electrical system. Its high storage capacity enables optimum exploitation of the potential provided by Brake Energy Regeneration.
Use of electrical power: due to the higher level of electrical power output available, additional vehicle functions can be powered purely electrically. The Auto Start/Stop Function for avoiding idling phases of the combustion engine is available virtually all the time and without any loss of comfort in conjunction with ActiveHybrid Technology.
The hybrid module is based on a technology which was conceived as part of the hybrid co-operation between BMW and Daimler. The hybrid co-operation successfully develops components for hybrid drives including high-power electronic systems and high-volt batteries. Here, the specific BMW design of the hybrid drive systems is ensured.
The concept car BMW Vision EfficientDynamics is fitted with a novel, highly efficient 8-speed automatic transmission developed jointly by BMW and ZF Getriebe GmbH. Presented here for the first time and ready for serial production use, this 8-speed automatic transmission makes an additional contribution to reducing fuel consumption and exhaust emissions with its direct connection to the engine and minimised torque-converter slip. The further increased shift dynamics and direct-find function for moving into the selected driving position promote a dynamic driving response. Power transmission is effected via the intelligent all-wheel drive system BMW xDrive, i.e. fully variably between the front and rear axle.
In the concept car BMW Vision EfficientDynamics there is also a solar roof which acts as an additional energy source for the vehicle power supply which is independent of the engine. High-power solar cells covering a surface area of some 1.0 square metres generate a maximum energy of one kilowatt hour for consumers inside and outside the vehicle. This enables pre-heating of the gear oil, thereby shortening the inefficient warm-up phase. What is more, direct energy supply is possible during standstill for ventilation or for operating a cool box, audio equipment, a mobile phone charger or for charging the vehicle battery, for example. This optimised the availability and use of electrical energy in a way which is CO2-neutral.
Exterior design
BMW Vision EfficientDynamics is based visually and technologically on the BMW X5. The BMW ActiveHybrid components are integrated in the vehicle in a way which is appropriate to the overall package. The generator and high-power electronic system are integrated in the transmission casing and thus invisible from the outside. A specially designed load compartment recess reflects the compact design of the lithium-ion battery.
An innovative rim design opens up additional potential in the optimi-sation of aerodynamics. The aero wheels of the concept car BMW Vision EfficientDynamics make an additional contribution to reducing fuel consumption, for example by requiring one kilowatt less of propulsion power at a speed of 160 km/h. The aerodynamic shaping of the spokes reduces rim ventilation. This has a positive impact on the aerodynamic properties of the vehicle.
