|The new 3.0-liter gaosline engine combines turbocharging, direct fuel injection and VALVETRONIC for the first time. Click to enlarge.|
For its Technology Day 2009 in Germany, BMW focused on describing its work with aerodyanmics, engines and transmissions in the context of its EfficientDyanmics development strategy.
The company presented the capabilities of its Aerodynamic Test Center and Aerolab; a new 3.0-liter gasoline unit combining turbocharging, direct fuel injection and VALVETRONIC fully-variable valve management; a new 3.0-liter twin turbo diesel with 2,000-bar injection pressure; and an 8-speed automatic transmission that can also be used in a hybrid application.
EfficientDynamics. BMW has been able to deliver significant improvements in its fleet CO2 emissions over the past few years. According to statistics compiled by the German Motor Vehicle Registration Authority cited by BMW, the average fuel consumption of all BMW and MINI vehicles registered in Germany in 2008 is 5.9 L/100 km (40 mpg US), with an average CO2 rating of 158 g/km. Both figures are significantly lower than the average of all vehicles registered in Germany in 2008.
From 2006 to 2008, BMW’s average fuel consumption and CO2 ratings decreased by 16%, the average MINI ratings by 20%. In all, the reduction in average CO2 emissions achieved by the BMW Group, as calculated by the German Motor Vehicle Registration Authority, is four times greater than the average figure for all car makers operating in the German market.
On a European level, BMW Group (BMW and MINI brands) fleet consumption between 1995 and 2008 has decreased more than 25%.
Aerodynamic Test Center. At the end of 2007, BMW completed its new €170-million (US$236-million) Aerodynamic Test Center (ATC) to help optimize the car’s aerodynamic qualities, resulting in improvements in performance, efficiency, and driving stability on the road.
Optimized aerodynamics have a direct impact on the car’s fuel economy and emission management; a reduction of air drag by 10% offers a reduction of fuel consumption on the road of more than 2.5%, according to BMW.
Beyond its enhanced integration into the vehicle development process, the ATC offers some unique facilities and capabilities in determining aerodynamic features and qualities in a realistic process. For example,
The ATC can analyze new models at a very early stage of development in a wide range of different situations with all test scenarios following real-life driving conditions. This means not only the consideration of all kinds of speed ranges, but also different driving situations such as driving in a bend, taking the actual movement of the body into account.
The ATC comprises a wind tunnel serving to analyse vehicles in their original size. To reproduce the most important effects and phenomena when driving on the road, the road surface is modelled through a simulation process using five rolling tracks.
A second wind tunnel allows the engineer to move the models tested from one position to the other by means of a control system operating in all directions above the world’s largest rolling road in a wind tunnel. This serves to analyse vehicle flow conditions under all kinds of circumstances, applying a concept already used for a number of years in motorsport.
The ATC Aerolab is now able for the first time to render and analyse the interaction of a car with other vehicles, for example when overtaking.
3.0 Liter Straight-Six Gasoline Engine with TwinPower Turbo. BMW’s new straight-six gasoline engine for the first time combines a twin-scroll turbocharger, direct fuel injection and VALVETRONIC fully variable valve management in one drive unit.
This 225 kW (306 hp) engine develops its maximum torque of 400 N·m (295 lb-ft) at an engine speed of just 1,200 rpm and maintains this level all the way to 5,000 rpm. In comparison with the straight-six featuring Twin Turbo technology and High Precision Injection already featured in several model series, the engine at the same time offers a further reduction of fuel consumption by up to 9%.
VALVETRONIC already plays a role worldwide in numerous BMW power units; the advantage of this system is infinite valve lift control on the intake valves, making the conventional throttle butterfly used in former engine generations superfluous.
VALVETRONIC reduces power losses in the charge cycle to a minimum and optimizes engine response. The significantly better response of a VALVETRONIC power unit results in particular from the fact that under-pressure in the part load range is only about 50 millibar, while in a conventional engine under-pressure is up to 800 millibar.
In developing the new engine, BMW’s engineers refined the system and all its functions by means of a new adjuster with its own integrated sensor ensuring even faster valve control and timing. Inertia of the new adjuster is only one-tenth of the former level of inertia on the “old” model, further improving engine response and behavior.
VALVETRONIC is fully integrated in the cylinder head for the first time in BMW’s new straight-six gasoline engine. This extremely compact configuration allows the combination of VALVETRONIC with High Precision Injection (direct injection), in which the injection nozzles are placed in the middle between the valves and therefore in the immediate vicinity of the spark plug in the cylinder head.
High Precision Injection in the new six-cylinder delivers fuel into the combustion chambers at a higher injection pressure of up to 200 bar over a wide range of running conditions. This, in turn, ensures extremely precise dosage of the fuel delivered and a particularly clean combustion process. A further advantage is that the cooler air/fuel mixture resulting from the direct injection of fuel allows a higher compression ratio than on a turbocharged engine with intake manifold injection, again benefiting power and performance.
Depending on the model, BMW will combine the new straight-six gasoline engine with a range of features and technologies from BMW EfficientDynamics, including technologies such as Brake Energy Regeneration; on-demand management of ancillary units such as the electrical coolant pump; the electrical steering assistance pump and the on-demand a/c compressor; as well as consistent lightweight technology; optimized aerodynamics including active air flap management and tires with minimum roll resistance.
The new straight-six may also be equipped in the future with the BMW Auto Start Stop function already used on the brand’s current four-cylinder models. In cars featuring a manual gearbox, in turn, a gearshift point indicator facilitates the choice of the ideal gear for maximum fuel economy.
The new six-cylinder is also the first turbocharged power unit to come with a map-controlled oil pump to reduce energy consumption and improve efficiency. The engine will meet the Euro 5 standard in Europe and ULEV II in the US. The new straight-six with BMW TwinPower Turbo will make its production debut in the BMW 5 Series Gran Turismo.
Straight-Six Diesel Engine with BMW TwinPower Turbo. This additional variant of BMW’s 3.0-liter straight six diesel delivers maximum output of 225 kW (306 hp) and peak torque of 600 N·m (442 lb-ft) at 1,500 rpm.
The newest 3.0-liter diesel features two substantial changes from its cousin. The first is an injection pressure of 2,000 bar. The second is a change in the TwinPower Turbo technology, which incorporates two turbochargers varying in size, harmonized with one another and acting either individually or together as a team, depending on current load requirements. The Variable Twin Turbo for the first time features variable turbine geometry on the small turbocharger unit.
Adjustment of turbine geometry is activated as a function of load conditions, via an electrical adjuster motor. This ensures early and smooth operation of the larger turbocharger interacting with the smaller turbocharger at low speeds and helps to build up a high level of power and performance under full load. The new engine reaches its maximum output of 225 kW at 4,400 rpm.
The engine also uses a new exhaust gas recirculation system, incorporating an exhaust pipe integrated in the cylinder head itself, a newly arranged intake pipe leading into the manifold, and more effective cooling. Optimized for maximum power, the stainless-steel exhaust gas cooler is positioned at the front of the engine and comes with a bypass flap limiting harmful emissions while the engine is warming up. The volume and temperature of exhaust gas may be determined precisely as a function of current running conditions and the temperature of the engine.
In various combinations specific to each model, EfficientDynamics technologies such as Brake Energy Regeneration, on-demand control of ancillaries such as the coolant pump, the fuel pump and the a/c compressor, as well as active air flap control and tires with minimum rolling resistance will be used.
The diesel particulates filter and the oxidation catalyst are housed in the same unit positioned directly behind the engine. The diesel particulates filter is maintenance-free; periodic regeneration is initiated by a subsequent injection process activated by the engine control unit at regular intervals.
|Eight-speed transmission. Click to enlarge.|
Eight-speed transmission. The new eight-speed automatic transmission, developed in partnership with ZF, adds further gears and covers an even wider range of gear increments than the former six-speed automatic transmission without any negative effects on the size and dimensions of the transmission, the weight of the entire unit, and its inner efficiency.
The eight forward gears and the reverse gear are provided by four simple gearsets and five shift elements. Only two clutches are open at a time in each gear, thus reducing friction losses to a minimum under all conditions and in every situation. In nearly all gearshifts, the transmission opens and closes only one clutch at a time, even when shifting down by more than one gear—a benefit so far provided only by a doubleclutch gearbox.
The eight-speed automatic transmission may be combined with hybrid drive. It is therefore part of BMW’s ActiveHybrid Technology combining an eight-cylinder gasoline engine with electric drive. This will be applied in a production BMW 7 Series hybrid model in 2009.