By Samuel Ee
As the top-of-the-line 5 Series model here, the BMW ActiveHybrid 5 represents the latest in petrol-electric hybrid technology. But thanks to the Green Vehicle Rebate, it is still priced lower than the BMW 535i with a conventional 3.0-litre turbocharged petrol engine. As with other hybrids, the ActiveHybrid 5 premium saloon has a sophisticated powertrain that combines an electric motor with a 3.0-litre inline six-cylinder petrol engine with forced induction. But unlike the usual fuel-sipping variety, this Beemer is a performance hybrid.
On its own, the petrol engine produces 306 hp and 400 Nm of torque, or exactly what the 535i also has. But with help from the synchronous electric motor's 55 hp and 210 Nm, the ActiveHybrid 5's total system output climbs to 340 hp and a prodigious 450 Nm in combined torque. It may sound like an easy thing to do but integrating an electric motor into the conventional propulsion system is actually highly complex. And on the ActiveHybrid 5, BMW has further improved the hybrid system.
On its conventional petrol-engined cars, the carmaker's eight-speed automatic transmission works with a torque converter. But for the hybrid drivetrain, the electric motor takes the place of the torque converter and the clutch is electronically controlled.
This results not only in increased operating efficiency but also a more compact powertrain package because the electric motor is located within the gearbox housing.
Also novel is the aircon compressor's dedicated motor. Normally belt-driven, it gets its own motor powered by the hybrid system's lithium-ion battery, which is located in the boot between the rear wheel arches.
While all these innovations should be integrated seamlessly, the ActiveHybrid 5 driver will find a palpable transition between the petrol and electric systems. But otherwise, the drive is smooth and quiet, especially when driven in all-electric mode. This can be done at up to 60 kmh. With the battery fully charged, the all-electric driving range is 4.0 km at an average speed of 35 kmh.
BMW ActiveHybrid 5
|Price: $323,800 (with COE)
Engine: 2,979cc inline-6 turbocharged
Transmission: 8-speed Steptronic automatic
Total system power: 340 hp @ 5,800 rpm
Total torque: 450 Nm @ 1,950-5,000 rpm
0-100kmh: 5.9 secs
Top speed: 250 kmh
CO2 emissions: 163 g/km
Distributor: Performance Motors 6319-0100
The straight-six petrol engine is only activated if the driver floors the accelerator pedal for more power. Depending on how much power is required, the electric motor actually provides a performance boost to complement the petrol engine's operation.
As a result, the ActiveHybrid 5 sprints from zero to 100 kmh in 5.9 seconds, or exactly the same time as the 535i despite it being 150 kg heavier than the latter at 1,925 kg.
Despite its dynamism, BMW says the ActiveHybrid 5 averages 6.4 to 7.0 litres of fuel per 100 km under the combined cycle. It helps that there are aids like the Eco Pro mode which allows the car to coast at speeds of up to 160 kmh with the combustion engine switched off and fully decoupled.
But as with all BMWs, the ActiveHybrid 5 also has more performance-oriented driving modes like Sport and Sport+. In these two modes, the handling of this rear-wheel-driven BMW saloon is satisfyingly sharp.
And it is this combination of economy and performance that makes the BMW ActiveHybrid 5 a very interesting hybrid.
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