Test Car Specifications
Model tested: BMW 3 Series plug-in hybrid prototype (330e)
Engine: 2.0-litre four-cylinder petrol and 80kW electric motor
Transmission: rear-wheel drive, eight-speed automatic
Body style: four-door saloon
CO2 emissions: 49g/km (VED Band A, £0 first year, £0 annually thereafter)
Combined economy: 134.5mpg (official)
Top speed: 140mph
0-62mph: 6.3 seconds
Total system maximum power: 252hp
Total system maximum torque: 420Nm
What's this?
Don't let the light disguise fool you, this is essentially a current 3 Series exterior. The real difference lies beneath, where the latest plug-in hybrid technology from BMW is fitted in a state that isn't be too far from series production. In fact, leaving aside the camouflage livery, the only noticeable exterior change is the addition of a small flap on the front left wing, which gives access to the battery charging port. Saying that, the new 330e will be launched when BMW gives the 3 Series a mild facelift later this year.
Unlike the ActiveHybrid 3 that is currently offered, this prototype can be plugged in to a public or domestic charge point in order to recharge the lithium-ion battery, which can give a driving range of up to 22 miles using only electric power. This is transmitted to the rear wheels via a 109hp electric motor that is derived from the BMW i3's and is located directly behind the engine without having any apparent impact on cabin space.
How does it drive?
The BMW eDrive system defaults to electric driving mode each time the car is started and will do so until the battery charge depletes or higher levels of power are requested by the driver - by applying greater pressure on the throttle pedal. With 230Nm available from the electric motor, the BMW's electric-only driving performance is sufficient to cope with everyday commuting. When the four-cylinder petrol engine engages it integrates with the drivetrain in a smooth fashion though in certain scenarios, namely when reapplying power exiting a corner, the finesse one would expect from a BMW is lacking. This is an issue that engineers working on the project are aware of and explain that this will be ironed out before the car enters series production.
Different drive modes can be chosen via the familiar Driving Experience Control button located beside the automatic gear selector. 'Eco Pro' mode extends the electric-only driving range slightly by lowering throttle sensitivity and reducing power to the air conditioning system. Lifting off the throttle in this mode also disconnects the motors in order to let the car coast freely - further benefitting the electric driving range.
At any stage, providing there is charge in the battery the 'eDrive' all-electric driving mode can be selected by pressing the dedicated button on the base of the gear selector. In this setting the car can drive at speeds of up to 74mph. Should you exceed this speed, or the battery's charge reduces to critical levels, the combustion engine immediately comes into play without causing any noticeable disruption to the drive.
Switching to 'Comfort' provides the driving mode that is likely to be used the most and delivers a good balance of both power and economy. When braking and off throttle the car's hybrid system regenerates energy to go back into charging the battery. The latter is housed directly over the rear axle in a bid to get as close to BMW's usual 50:50 weight distribution as possible.
For more spirited driving 'Sport' mode engages both the internal combustion engine and the electric motor in tandem to deliver the maximum 252hp and 420Nm. The result is a power delivery that is on a part with some of the larger petrol-engined 3 Series models. Through tighter corners there is little difference in driving dynamics even though the plug-in hybrid and battery system adds a further 165kg to the kerb weight. The level of balance and composure from the chassis is very good.
Verdict
With a near-diesel-rivalling 400 miles or so driving range and performance that almost matches that of the BMW 330i, the 330e plug-in hybrid could be the best of both worlds. For it to really work though it will have to be a more affordable than the ActiveHybrid 3, which carries a prohibitively expensive price tag. Taking that into account, providing some of the minor areas in need of improvement are sorted by the time it reaches series production, BMW could have a very competitive and complete package on its hands that could deal a significant blow to diesel sales.
