BMW extends X6 Range with Active Hybrid X6

Through its combination of a V8 gasoline engine and electric drive, the BMW ActiveHybrid X6 offers a significant increase in dynamic performance together with a reduction of fuel consumption and emissions by approximately 20 per cent. This joint enhancement of driving pleasure and efficiency clearly proves that the BMW ActiveHybrid X6 is a typical BMW in the hybrid segment.

The overall drive system featured in the BMW ActiveHybrid X6 consists of a 300 kW/407 hpV8 gasoline engine with BMW TwinPower Turbo Technology and two electric synchronous motors delivering 67 kW/91 hp and, respectively, 63 kW/86 hp. Maximum system output is 357 kW/485 hp, peak torque is 780 Newton-metres/575 lb-ft.

Precisely controlled interaction of the three power units optimises the overall efficiency of the BMW ActiveHybrid X6 at all speeds, with acceleration from a standstill to 100 km/h in 5.6 seconds. Top speed of the BMW ActiveHybrid X6 is limited electronically to 236 km/h or 146 mph (250 km/h or 155 mph with the optional Sports Package, with average fuel consumption in the EU test cycle of 9.9 litres/100 km (equal to 28.5 mpg imp) and a CO2 emission rating of 231 grams per kilometre.

BMW’s first full hybrid model is able to run exclusively on electric power – and that is entirely free of CO2 – up to a speed of 60 km/h or 37 mph, with the combustion engine being activated automatically whenever required.

Ideal variation of the two drive modes for enhanced efficiency and dynamism is ensured by The two-mode active transmission provides the ideal combination of the two power modes for enhanced efficiency and dynamic performance at all times. With the two electric motors, three planetary gearsets and four multiple-plate clutches, drive power is transmitted through a seven-gear automatic transmission operated by the driver of the BMW ActiveHybrid X6 via an electronic gear selector lever and, respectively, shift paddles on the steering wheel.

BMW’s intelligent xDrive all-wheel-drive system spreads out engine power variably between the front and rear wheels.

The electric motors receive their energy from an NiMH high-performance battery positioned beneath the floor of the luggage compartment and feeding electric power also to the car’s on-board network. Luggage compartment capacity is therefore the same as on the “regular” BMW X6 with its combustion engine. When applying the brakes or taking back the gas pedal kinetic energy is converted into electrical energy and is stored in the high-performance battery. To provide this function either one or both of the electric motors acts as a generator, feeding electric power generated without the slightest increase in fuel consumption directly into the high-voltage battery. Subsequent use of this energy to provide extra drive power significantly reduces the consumption of fuel.

BMW ActiveHybrid technology raises the development of drive systems enhancing both efficiency and dynamism in one to a new, unprecedented standard, clearly confirming BMW’s superior competence in development in this area. Now the introduction of this innovative technology in such an exceptional vehicle concept adds a particularly fascinating motoring experience through the efficiency achieved in this way. Through its size, character and driving dynamics, the world’s one and only Sports Activity Coupé is particularly well-suited to combine the progressiveness and the potential of BMW ActiveHybrid technology to a standard never seen before.

Unique efficiency ensured by two-mode active transmission.

BMW ActiveHybrid technology has been developed specifically for use in a particularly dynamic vehicle in this segment and for a broad range of practical use going far beyond city traffic as such. The big advantage, therefore, is the overall optimisation of drivetrain efficiency in all speed ranges and under all conditions.

The two-mode active transmission is based on an ECVT (electric continuously variable transmission) operating in two separate modes. One mode is for setting off with particular power and for driving at low speeds, the second is for motoring at high speeds.

When setting off only one of the two electric motors is activated. Then, as soon as the driver requires more power, the second electric motor automatically activates the combustion engine and subsequently serves as a generator providing a permanent supply of electric power.

When driving steadily at a higher speed most of the power required is delivered by the combustion engine in a largely mechanical process. Here again, one of the two electric motors acts as a generator.

Together with the mechanical components, the electric motors form a joint transmission unit providing the optimum transmission ratio at all times as a function of driving conditions. The mechanical link within the two-mode active transmission is provided by three planetary gearsets in a configuration dividing the drive power generated by the combustion engine and the two electric motors into two transmission modes and therefore ensuring a degree of variability in combining the two power sources conventional hybrid drive would not be able to provide.

The two operating modes of the electric motors are supplemented and enhanced by fixed transmission ratios providing a total of seven gears for full use of the highly efficient hybrid function throughout the vehicle’s complete range of operation and at the same time maintaining the driving performance so typical of BMW.

Conventional but unique all in one: V8 gasoline engine with BMW TwinPower Turbo Technology and High Precision Injection.

The combustion engine is a technically unique eight-cylinder featured for the first time in the BMW X6 xDrive50i. The world’s first V8 gasoline engine with two turbochargers in the V-section between the two rows of cylinders excels in particular through its smooth development of power setting in from the start and continuing in an ongoing surge throughout the entire speed range. The exceptionally spontaneous and direct response of this V8 with BMW TwinPower Turbo Technology results directly from the compact configuration of the engine allowing short manifolds as well as large cross-sections on the intake and exhaust side.

Displacing 4.4 litres, this outstanding eight-cylinder delivers maximum output of 300 kW/407 hp consistently maintained between 5,500 and 6,400 rpm. Superior torque of 600 Newton-metres/442 lb-ft is maintained all the way from 1,750 to 4 ,500 rpm, with High Precision Injection ensuring precise supply of fuel at all times.

Piezo-injectors positioned in the middle between the valves ensure a smooth, efficient and clean combustion process, the V8 naturally fulfilling both the European EU5 standard as well as the ULEV II limits in the USA.

Compared with the power unit featured in the BMW X6 xDrive50i, this new engine has been modified in numerous respects to the specific requirements of the BMW ActiveHybrid X6. The first point is that there is no starter, no alternator and belt drive for the climate compressor and hydraulic pump on the power steering. The main and low-temperature circuits in the cooling system have been modified for all-electric operation, the low-temperature circuit already serving to cool the charge air in the combustion engine being used additionally to cool the power electronics.

Electric motors for enhanced performance on no extra fuel.

When accelerating the eight-cylinder power unit of the BMW ActiveHybrid X6, joining forces with the electric motors, ensures optimum efficiency and dynamic performance. As soon as the driver requires more power the two electric motors fed by the high-voltage energy battery supply additional torque for enhanced performance. This boost effect significantly increases the overall output of the BMW ActiveHybrid X6, without any increase in fuel consumption.

While the two electric motors have almost the same output, they have been modified in their performance characteristics to meet individual requirements. The power delivered is 67 kW/91 hp and. respectively, 63 kW/86 hp, with peak torque of 260 Newton-metres/192 lb-ft and 280 Newton-metres/206 lb-ft.

The electric motors support the combustion engine effectively throughout the entire speed range, the additional electrically generated drive power serving to reduce the power output required on the combustion engine when driving steadily at a higher speed. This shift in load is perfectly controlled at all times to give the overall system enhanced efficiency and its maximum effect under practical driving conditions.

The electronic control unit is also able to provide a consistent, ongoing surge of power, maximum power being generated when shifting gears through the so-called response boost effect. When kicking down the accelerator for maximum acceleration, the control unit generates stationary boost right from the start in the initial downshift phase, interaction of response boost and stationary boost ensuring a very spontaneous and direct response to every movement of the gas pedal.

Maximum system output is 357 kW/485 hp, with peak torque of 780 Newton-metres/575 lb-ft. This makes the BMW ActiveHybrid X6 the most powerful hybrid vehicle in the world, with acceleration from a standstill to 100 km/h in just 5.6 seconds and top speed is limited electronically to 236 km/h or 146 mph (or, respectively, 250 km/h or 155 mph with the optional Sports Package).

The unique positon of BMW ActiveHybrid X6 within the BMW X segment as a whole follows very clearly and convincingly from the comparison of these performance figures, on the one hand, with the vehicle’s fuel consumption and emission ratings, on the other. The BMW ActiveHybrid X6 combines its supreme dynamism with equally fascinating efficiency, with fuel average fuel consumption in the EU test cycle of just 9.9 ltr/100 km (equal to 28.5 mpg imp) and a CO2 rating of 231 grams per kilometre.

All-electrical driving mode reducing emissions to zero.

With its combination of two-mode active transmission and high-performance battery, the BMW ActiveHybrid X6 is able to run on its electric motors alone. This makes it a zero emission vehicle under such conditions, fulfilling even the strictest requirements foreseen for the future and ensuring the highest conceivable level of mobility.

The BMW ActiveHybrid X6 may run on electric power alone regardless of the ambient temperature, minimum operating temperatures being required only for the engine coolant, transmission fluid and high-voltage battery. A further requirement is that the high-performance battery is adequately charged.

Top speed in the electric mode is 60 km/h or 37 mph, maximum range is 2.5 kilometres (1.6 miles).

While driving electrically, the BMW ActiveHybrid X6 retains all its safety and comfort functions. The brakes remain fully operative thanks to electronic vacuum supply, not requiring the combustion engine to develop their full effect. The same applies to the EPS Electronic Power Steering, with steering assistance being generated as required and with maximum efficiency by an electric motor.

Even the air conditioning remains fully available without any restrictions, running efficiently on an electrical climate compressor. And since the high-performance battery supplies electric power to the complete 12-volt on-board network through a voltage converter regardless of the driving mode, all other power-consuming items such as the lights and the on-board entertainment system remain fully functional at their usual, consistent level.

Recuperation: electric power generated without additional fuel consumption.

The BMW ActiveHybrid X6 features an enhanced version of Brake Energy Regeneration already used in BMW’s current models running on a combustion engine alone, generating the electric power saved in the high-performance battery. In this case the electric motors act as generators in overrun and when applying the brakes in order to feed electric power into the high-voltage battery unit, again in the interest of maximum efficiency.

This uses energy otherwise simply lost in conventional vehicles as heat escaping through the brakes – and depending on road speed, one or both of the electric motors may perform this function.

The power delivered by the generator is approximately 50 kW, about 25 times as much as the power provided so far by Brake Energy Regeneration.

Generator delivering electrical brake power.

In the generator mode the two electric motors supply a lot of the energy required to slow down the vehicle whenever necessary. Indeed, the stopping power generated in this way is up to 3 metres/sec2 or, respectively, 0.3 g in a purely recuperative process, significantly reducing the load acting on the mechanical brake system.

Sensotronic Brake Actuation (SBA) in the BMW Active Hybrid X6 may be used at any time without a direct mechanical connection between the brake pedal and the hydraulic circuit. Pedal movement is recorded by sensors and split up by a control unit into brake power generated in a regenerating and in a hydraulic process. At the same time an integrated pedal force simulator generates the usual brake feeling for the driver as an additional factor in this brake-by-wire solution.

The active brake servo builds up brake pressure with electrical control according to the signals emitted by the control unit. To ensure brake power assistance also in the all-electric mode, the BMW ActiveHybrid X6 comes furthermore with an electrical under-pressure pump replacing the vacuum pressure in the intake system of the combustion engine on a conventional vehicle. A mechanical fallback function, in turn, guarantees full operation of the brake system in the event of a failure or deficiency in the electrical system, in which case the stopping power required is generated by the hydraulic system alone, like on a conventional vehicle.

The primary task of the SBA system is to split up the brake power required by the driver into a regenerating and a hydraulic brake factor. Via the xDrive powertrain, the hybrid system in the BMW ActiveHybrid X6 is able to transmit brake forces to all four wheels generated by the stopping power of the recuperative electric motors. And whenever the stopping power required exceeds the level of 3 metres/sec2, the control unit builds up additional brake force through the mechanical brake by means of the active brake servo.

In braking situations critical to driving stability the control unit receives additional signals from the DSC Dynamic Stability Control, intervening in the brakes and engine management to keep the vehicle safely on course. This ensures safe braking manoeuvres under all conditions, with all driving stability systems developing their complete effect when required regardless of whether the stopping power needed is generated electrically or hydraulically.

A further point is that all driving stability systems are tailored in their operation to the dynamic character of the Sports Activity Coupé also on the BMW ActiveHybrid X6. DTC Dynamic Traction Control selected at the touch of a button, for example, provides maximum traction and drive power on loose surfaces such as snow or sand thanks to its higher slip thresholds. And with the DTC mode activated, the driver may opt for a particularly sporting style of motoring all the way to a controlled power slide in bends.

BMW xDrive: intelligent all-wheel drive for extra performance, optimum driving stability and supreme traction.

The sports-oriented driving behaviour of the BMW ActiveHybrid X6 is also attributable to xDrive all-wheel-drive technology. Permanent all-wheel drive with electronically controlled, variable distribution of drive power front-to-rear gives the BMW ActiveHybrid X6, like all BMW X models, not only superior traction, but also enhanced driving dynamics.

BMW xDrive qualifies as an intelligent all-wheel-drive system in particular through the smooth division of drive power ensured by a power divider with an electronically controlled multiple-plate clutch feeding the appropriate level of power to the right axle with optimum wheel contact and grip on the road.

Under normal conditions BMW xDrive spreads out drive power to the front and rear axle in a 40:60 split, sensors consistently measuring wheel slip both front and rear. The system is able to vary the balance of drive power within fractions of a second, BMW xDrive, unlike conventional all-wheel-drive systems, thus looking ahead and not only responding when a wheel is already spinning.

Benefiting from these abilities, BMW xDrive raises the driving dynamics of the BMW ActiveHybrid X6 to an even higher level by recognising even the slightest tendency to over- or understeer right from the start and taking appropriate counter-action.

EPS Electronic Power Steering for even greater driving comfort.

The BMW ActiveHybrid X6 is the first BMW X model to feature EPS Electronic Power Steering. This allows active steering assistance both when driving with the combustion engine and in the all-electric mode.

EPS provides optimum steering assistance under all conditions to give the driver that special feeling so typical of the BMW brand. Another advantage is the further reduction of fuel consumption, EPS significantly reducing the energy required for steering assistance compared with conventional, hydraulic power steering, since Electronic Power Steering only becomes active when steering assistance is actually required or desired by the driver. So when driving straight ahead in a straight line, for example, the electric motor does not consume any energy whatsoever.

Electronic Power Steering on the BMW ActiveHybrid X6 comes complete with fully integrated speed-related Servotronic steering assistance, the reduction of assistance at high speeds ensuring not only safe directional stability but also extremely precise steering behaviour in bends as well as the safe feeling at high speeds again so characteristic of a BMW. At low speeds, on the other hand, for example when parking, extra power assistance significantly reduces the steering forces required.

Liquid cooling for even greater performance on the high-performance battery.

The high-voltage battery featured in the BMW ActiveHybrid X6 comes in nickel-metal hydrid technology (NiMH). Capacity is 2.4 kWh, with 1.4 kWh available actively for practical use. Maximum output, in turn, is 57 kW, with the battery’s control unit permanently determining the output level currently available as well as the charge status of the battery.

The high-performance battery comes with its own liquid cooling system incorporating a heat exchanger to cool the battery through the flow of air from the outside and, additionally, through the cooling circuit in the air conditioning. These two circuits are activated either individually or in combination with one another, depending on current requirements, the control unit selecting the most effective and efficient cooling option as a function of ambient temperature and the temperature of the high-voltage storage unit.

Cooling by the air conditioning is activated by an appropriate switch valve, with the electrical climate compressor being switched on automatically whenever required. The interior and the high-voltage battery being cooled separately of one another, cooling is far more efficient than with a system using air cooling only, raising the energy storage medium to a far higher level of performance and retaining the hybrid functions longer in extreme weather and whenever the driver prefers a very sporting style of motoring. Ultimately, this gives BMW ActiveHybrid X6 an outstanding potential in driving dynamics far superior to other hybrid vehicles in the market.

Intelligent energy management and integral safety concept.

Power electronics developed especially for BMW ActiveHybrid technology ensures energy management on board the BMW ActiveHybrid X6 both very efficient and flexible in use. The electronic control system consistently controls the distribution of energy as a function of ambient conditions, the status of the vehicle, and the demands made by the driver. The most important incoming and control factor for the operating strategy chosen is the charge status of the high-performance battery saving the electrical energy generated through recuperation.

The BMW ActiveHybrid X6 naturally complies in full with the integral safety concepts developed for hybrid vehicles by BMW. With central control functions being integrated both in the power electronics and the energy battery, the system has the ideal starting point for fulfilling all kinds of international crash test standards as well as the demanding internal standards of the BMW Group, in particular guaranteeing the highest level of operating safety on all components in the high-voltage on-board network.

Some of the features of this safety concept are the different colours of cables to avoid any confusion, the presentation of clear safety warnings and the all-round cover on the entire system using extra-large insulation panels and newly developed connectors.

The high-voltage battery is housed in a high load-resistant steel casing and is fitted firmly inside the car, just above the rear axle at an extremely safe point for the event of a collision. The status of the storage modules is constantly supervised by integrated safety electronics, the driver being informed immediately of any malfunction and, wherever necessary, the entire system being automatically discharged and deactivated.

In the event of a collision, the system is switched off automatically within fractions of a second, the car’s central safety electronics assessing the severity of an accident and ensuring a safe operating mode as a function of current, individual requirements.

Special hybrid drive Auto Start Stop function.

In city traffic the BMW ActiveHybrid X6 can be run in the all-electric mode without using the combustion engine. A further advantage is that the vehicle comes with a new generation of Auto Start Stop technology featured here for the first time. Tailored specifically to the requirements of a hybrid car, this new Auto Start Stop function allows a much higher standard of comfort and is available more often than the conventional system. Automatic deactivation of the combustion engine at a road junction or at the traffic lights does not in any way impair the driving experience, just as the V8 power unit will start again immediately as soon as the driver presses down the gas pedal.

BMW ActiveHybrid X6 provides the Auto Start Stop function consistently at all outside temperatures, no matter how cold or how hot.

As long as the engine is switched off, the electric climate compressor automatically maintains the climate and temperature desired within the passenger compartment. All other electrically operated functions are also maintained, with the on-board network being consistently supplied with power from the high-voltage storage unit. The only way to deactivate the special hybrid Auto Start Stop function is by choosing the manual gearshift mode on the automatic transmission.

Additional displays informing the driver of the operating status and efficiency of the hybrid system.

Operation of the hybrid system and current operating conditions are presented clearly and understandably in the displays. The most important information is shown in the central instrument cluster, clearly separated according to the various operating modes. Further information and technical explanations, in turn, are shown in the Info Display in the centre console.