BMW X6 ActiveHybrid
ActiveHybrid technology provides a glimpse into the future, achieving outstanding driving dynamics with equally impressive efficiency. It melds both of these qualities to offer a truly unique driving experience. The world’s first Sports Activity Coupe with full hybrid drive capitalizes on the options offered by combining the combustion engine with electric motors to create a powertrain with new levels dynamic performance and efficiency.
BMW ActiveHybrid technology offers a significant increase in driving dynamics and at the same time reduces fuel consumption by approximately 20 percent versus a comparable vehicle powered by a combustion engine alone. The result is even greater driving pleasure combined with enhanced fuel economy and CO2 management providing the kind of progress to make the BMW ActiveHybrid X6 a genuine BMW in the hybrid market.
The overall drive system featured in the BMW ActiveHybrid X6 consists of a 400 hp twin-turbocharged V8 gasoline engine and two electric synchronous motors delivering 91 hp and 86 hp, respectively. Maximum system output is 480 hp, and peak torque reaches 575 lb-ft.
Precisely controlled interaction of the three power units optimizes the overall efficiency of the BMW ActiveHybrid X6 at all speeds, with acceleration from a standstill to 60 mph in 5.4 seconds. Top speed of the BMW ActiveHybrid X6 is limited electronically to 130 mph, with average fuel consumption in the EU test cycle improved by roughly 20%, and a CO2 emission rating of 231 grams per kilometer. EPA ratings will be available closer to the market introduction.
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 37 mph (60 km/h), with the combustion engine being activated automatically whenever required.
These performance figures are made possible by utilizing a two-mode active transmission. The ideal combination of the two power modes can be controlled for enhanced efficiency and dynamic performance in any driving condition. With the two electric motors, three planetary gearsets and four multi-plate clutches, drive power is transmitted through a 7-speed automatic transmission.
As would be expected in a BMW, the driver can operate the transmission manually. BMW’s lauded xDrive all-wheel-drive system distributes the power between the front and rear axles.
The electric motors receive their energy from an NiMH high-performance battery pack positioned beneath the floor of the luggage compartment. This battery pack also feeds electric power to the vehicle’s on-board network. Luggage compartment capacity is therefore the same as on the original BMW X6. On brake application and/or on deceleration, kinetic energy is converted into electrical energy and is stored in the battery pack. To provide this function either one or both of the electric motors act as a generator, feeding electric power generated back into the high-voltage battery.
Unique efficiency ensured by two-mode active transmission. BMW ActiveHybrid technology has been developed specifically for use in a particularly dynamic vehicle and for a broad range of practical use. The big advantage, therefore, is optimization of drivetrain efficiency in all speed ranges and conditions.
The two-mode active transmission is based on an ECVT (electric continuously variable transmission) operating in two separate modes. One mode is for stop-and-go driving and low speeds, and the second is for driving at higher speeds.
From a stop and at low speeds, only one of the two electric motors is activated. As soon as the driver requires more power or increased speed, the second electric motor automatically starts the combustion engine. The second electric motor then serves as a generator to provide a supply of electric power to the vehicle systems. 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.
The mechanical components, including three planetary gearsets and the two electric motors, combine to provide for seven total effective gears. This configuration manages the power generated by the combustion engine and two electric motors in a way that maximizes driving versatility.
Twin-turbocharged V8 gasoline engine with High Precision Direct Injection. The combustion engine is the innovative reverse-flow V8 first featured 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 develops power throughout the entire engine speed range. The spontaneous and direct response of this engine results from its compact configuration, which allows the shortest exhaust manifolds.
Displacing 4.4 liters, this outstanding engine delivers its maximum output of 400 hp between 5,500 and 6,400 rpm. Peak torque of 450 lb-ft is maintained from 1,750 to 4,500 rpm, with High Precision Direct Injection ensuring precise supply of fuel at all times. Piezo-injectors positioned in the combustion chambers between the valves ensure a smooth, efficient and clean combustion process. The engine fulfills the European EU5 standard as well as the ULEV II standards in the US.
Compared with the engine featured in the BMW X6 xDrive50i, this version has been modified in numerous respects to the specific requirements of the BMW ActiveHybrid X6. There is no starter, alternator, or belt drive for the air-conditioning compressor and hydraulic pump. The dual-circuit cooling system has been modified for all-electric operation.
When accelerating, the V8 engine of the BMW ActiveHybrid X6 joins forces with the electric motors to ensure optimum efficiency and dynamic performance. When the driver requires more power, the two electric motors supply additional torque for enhanced performance. This boost effect significantly increases the overall output of the vehicle, without increasing fuel consumption.
While the two electric motors have almost the same output, they have been modified in their performance characteristics to meet specific requirements. The power delivered is 91 hp and 86 hp, respectively, with peak torque values of 192 lb-ft and 206 lb-ft.
The electric motors support the combustion engine effectively throughout the entire speed range. The additional electrically-generated drive power reduces the power output required of the combustion engine when driving at steady highway speeds. Load shifts are managed to give the overall system enhanced efficiency under the full spectrum of driving conditions. During kick-down and maximum acceleration shifts, the electric motors help provide an additional boost of power.
Maximum system output is 480 hp, with peak torque of 575 lb-ft. This makes the BMW ActiveHybrid X6 the most powerful hybrid vehicle in the world, with acceleration from a standstill to 60 mph in just 5.4 seconds and top speed is limited electronically to 130 mph.
Source: BMW press