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Thursday, February 21, 2008

BMW X5 Twin Turbo Hybrid Concept

BMW are pulling out all the stops to beat Ken Livingston’s increase in the London Congestion charge. Porsche are heading to the courts while BMW are spending money on innovation.

To be revealed at the Geneva show, BMW’s Vision EfficientDynamics Concept is jam packed with innovative new state-of-the-art technology aimed at reducing emissions and improving efficiency। Based on the bulky X5, the Vision EfficientDynamics Concept is one of the first Diesel Hybrid applications in a passenger car. Only a few other manufacturers like Mercedes, PSA and Ford have shown Diesel Hybrid systems in the past. The vehicle employs a highly developed 2.0L turbo diesel four cylinder engine that uses variable twin turbo system and 3rd generation common rail technology to produce an impressive 204hp and 400Nm of torque. This powerplant is assisted by a mild Hybrid concept that uses a compact generator to provide up to 20hp more power and a whopping 210Nm of torque. All the torque is fed through a new 8 speed automatic transmission developed in conjunction with ZF. The greater spread of gear ratios should allow the engine to run at its more optimal speed/load point for a given road speed. BMW quote 43.5mpg or 172g/km CO2 of on the combined cycle, which is hugely impressive for a vehicle the size of the X5. The car is also equipped with BMW’s regenerative braking system and photovoltaic solar panels mounted to the roof.

It makes perfect sense to couple a hybrid system to a diesel engine। Diesel engines are significantly more efficient than a gasoline engines but generally cost substantially more as a unit. This is a result of their complex fuel injection systems and the obligatory turbocharger, in this case two. Modern diesels emit fewer CO2 emissions too as a result of using less fuel. The cost of the diesel engine has to be added to the hybrid generator and the batteries and all of a sudden you are looking at a very expensive vehicle. Nevertheless, directionally it is a great step forward and perhaps those central London dwellers can still have their SUV fix after all. Read on for more details.

Press Release

BMW Vision EfficientDynamics Concept Revealed

Offering an insight into the future of BMW’s innovative EfficientDynamics technologies

The Geneva Motor Show (4 – 16 March) will mark the world premiere of the BMW Vision EfficientDynamics, a concept car designed to showcase the future direction of BMW’s performance enhancing and emissions lowering innovations. Mild ActiveHybrid technology is combined with a twin-turbocharged four-cylinder diesel engine, a new eight-speed automatic gearbox and even roof-mounted solar panels, and all shrouded in a BMW X5 body.

All of these technologies combine to deliver the best fuel economy and lowest emissions of any large 4x4 currently on sale. The BMW Vision EfficientDynamics delivers 43.5mpg on the combined cycle and just 172g/km of CO2 emissions. However, these frugal figures do not translate into low performance figures. With its twin-turbocharged two-litre diesel engine delivering more than 100hp per litre, the BMW Vision EfficientDynamics concept completes the sprint from zero to 62mph in just 8.9 seconds, a time faster than most current production competitors.

The 2.0-litre four-cylinder diesel engine in the BMW Vision EfficientDynamics uses BMW’s Variable Twin Turbo concept, third-generation common-rail injection and an all aluminium crankcase to deliver 204hp and 400Nm of torque between 2,000 and 2,250rpm. The engine is supplemented by a mild hybrid concept that delivers a further 20hp and 210Nm of torque under acceleration. As a consequence, even though the BMW Vision EfficientDynamics features a relatively small capacity engine, it delivers nearly the same levels of horsepower as the conventional X5, but offers improvements in its already class-leading consumption and emissions figures.
The mild hybrid solution in the BMW Vision EfficientDynamics uses a compact generator that, for the first time, is flange mounted directly onto the gearbox. This motor produces up to 20hp of on-demand power. In addition, BMW’s now familiar Brake Energy Regeneration is used to efficiently capture energy that would previously have been lost when the engine is on overrun. Innovatively, the alternator is also integrated into the crankcase rather than conventionally driven from the front of the engine.

BMW’s concept uses highly efficient lithium-ion batteries in the boot area to store the power generated. These high-storage-capacity batteries enable optimum use of Brake Energy Regeneration. In addition, they create possibilities to power the air conditioning, electric coolant pump and the electric power steering system. For these functions, a 120 volt vehicle power system was designed and runs in parallel with the conventional 12 volt system.

The power harnessed by the batteries is also supplemented by roof mounted photovoltaic solar panels, measuring 1.0 metre square. The energy generated can either be used immediately or stored for later use. Importantly, the power created in this zero- CO2 way can be used to pre-heat the diesel fuel. The less efficient warm-up phase is thus shortened considerably.

This innovative and technologically advanced engine is directly mated to a new eight- speed automatic transmission. Developed jointly between BMW and ZF, the new gearbox delivers fast and efficient gear changes. With such a spread of gears, the car will always be in exactly the right ratio for the prevailing driving conditions. It also improves fuel consumption and minimises emissions.

The chassis and ride-height of the X5 have been adapted for the BMW Vision EfficientDynamics. This includes aerodynamically-efficient 19-inch light alloy wheels with reduced ventilation. The design of the spokes reduces wind resistance to the extent that, at 100mph, the car has to produce one horsepower less than a conventionally-wheeled car. This benefit has not been included in the fuel consumption calculations but, on the road, the impact is noticeable.

Source: BMW

Related entries:

BMW X6 ActiveHybrid Spied
BMW X6 Active Hybrid Concept


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