By November 30, 2010 Read More →

Road Test: 2011 BMW ActiveHybrid X6

BMW X6 ActiveGybrid 2010_01There are few exterior details, where BMW ActiveHybrid X6 differs from the standard X6. One and probably most noticeable is the Powerdome on the engine lid, which is required to make room for the hybrid technology in the engine bay. Of course there are also “ActiveHybrid” model designations on the tailgate and on the front doors. ActiveHybrid has 19-inch light-alloy wheels or, as an option, 20-inch light-alloy wheels in aerodynamically optimised Streamline design. ActiveHybrid can also be ordered with an exclusive exterior paintwork, the Bluewater metallic.

The basis of the drive system in the BMW ActiveHybrid X6 is the 4.4-litre V8 with BMW TwinPower Turbo Technology. The petrol engine alone produces 407 hp. It is assisted by two electric motors developing 91 hp and 86 hp. Drive system’s maximum combined output is 485 hp and peak torque 780 Newton metres. This makes the X6 ActiveHybrid the most powerful hybrid vehicle in the world. Acceleration from a standstill to 100 km/h takes 5.6 seconds and the top speed is 236 km/h, or 250 km/h with the optional Sports Package. ActiveHybrid technology offers three modes of driving. Depending on the driving situation, ActiveHybrid can drive with the combustion engine, with the electric power alone, or benefit from the combination of the both driving modes.

You don’t really notice the changes between combustion and electric power, except that suddenly it gets a bit quieter inside and the rev counter shows zero, when the combustion engine stops. At first it feels a bit unbelievable that car this big can be moving just by electric power and even with speed as high as 60 km/h. Although driving with electric power is only possible when driving at a steady speed. The combustion engine cuts in quickly when you need to accelerate.

Driving in the electric mode is possible up to the speed of 60 km/h and the range of 2.5 kilometres, after which you have to start loading the battery again. Eventhough you can drive only short distances with electric power alone, the electric motors support the combustion engine effectively throughout the entire speed range. The additional, electrically generated drive power helps to reduce the power output required on the combustion engine when driving steadily at a higher speed. ActiveHybrid’s average fuel consumption in the EU5 test cycle is 9.9 litres/100 km (28.5 mpg) and the CO2 emission rating is 231 grams/kilometre.

When using the brakes or easing on the gas pedal, kinetic energy is converted into electrical energy and stored in the high-performance battery. This is achieved by one or both electric motors act as a generators, depending on driving conditions. The recuperation efficiency and output achieved by the system is 25 times greater than with Brake Energy Regeneration featured so far in BMW’s production models. Electrical energy is stored in an NiMH high-performance battery with a capacity of 2.4 kWh. The temperature of the high-voltage battery is controlled as required and with maximum efficiency by liquid cooling interacting with the air conditioning and an external heat exchanger.

While driving electrically, the ActiveHybrid 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 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.

BMW ActiveHybrid X6 is the first BMW X model to feature EPS Electronic Power Steering. This allows active steering assistance in-all electric mode and when driving with the combustion engine. Electronic Power Steering also helps to reduce the fuel consumption. Since EPS only becomes active when steering assistance is actually required, it significantly reduces the energy required for steering assistance compared with conventional, hydraulic power steering. Driving straight ahead in a straight line, the electric motor does not consume any energy whatsoever.

Unfortunately the EPS doesn’t offer the same kind of steering feel that we are used to have in a BMW. ESP comes with integrated speed-related power assistance (Servotronic), which makes the steering heavier on higher speeds. X6 is easy to drive around city corners with its light steering, but on the road we would have hoped for a better steering feedback, which is a big part of driving enjoyment, especially in a BMW.

BMW X6 ActiveGybrid 2010_02

Specification

Engine

  • Petrol
  • 8-cylinder
  • 4395cc
  • Twinturbo
  • Hybrid

Power

  • 357 kW (485 hp)

Torque

  • 780 Nm (575 lb-ft)

Transmission

  • 7-speed automatic
  • AWD

0-100km/h / 0-62mph

  • 5.6 seconds

Top speed

  • 236 km/h

Fuel consumption

  • 9.9 l/100km
  • 28.5 mpg

CO2 emissions

  • 231 g/km

BMW X6 ActiveGybrid 2010_03