Behind the wheel - 3 SERIES #F30
Plug-In Hybrid Prototype
Charges BMW’s plug-in hybrid technology moves the game on significantly from where the ActiveHybrid started off 3Series Ahead. Words: Dave Humphreys Photography: #B#MW
It was #2012
introduced the #ActiveHybrid
3. It was coupled with the TwinPower six-cylinder engine from the #335i
and had a 55hp electric motor powered by a high-voltage lithiumion battery. This combination drove the rear wheels via an eight-speed automatic transmission and ensured a sub-six second dash to 62mph from rest. The more important figures at the time were the 51.4mpg fuel economy, a CO² emissions output of 139g/km and the ability to drive up to a distance of 2.5 miles solely using electric power. However, compare this to the best-selling 320d Saloon of today and the ActiveHybrid 3 starts to make less sense as it falls behind in both fuel economy and CO² output – and that’s before you consider the sizeable price premium that it commands.
Enter the next generation of 3 Series hybrid, which harnesses plug-in technology and the latest in electric motors derived from its BMW i division. Gone is the 3.0-litre straight-six engine and in its place is the #B48
2.0-litre four-cylinder TwinPower turbocharged unit. Mounted aft of the engine is a 95hp electric motor powered by a high-voltage lithium-ion battery that is located over the rear axle. Emissions fall to 50g/km, while the official fuel economy rating of 140mpg is a significant advancement over the ActiveHybrid 3 – even if those figures are elevated by the low-speed, low-distance nature of the official test procedure. The new 3 Series hybrid may share much of its eDrive technology with the i3 and i8, but it won’t be as radically styled. In fact, one of the only visual clues as to its plug-in hybrid underpinnings is the placement of the battery inlet flap on the wing behind the front left wheel arch. Once in final production trim the car is also likely to have subtle ‘eDrive’ badging and aerodynamically-optimised model-specific alloy wheels, which will be shod in low rolling resistance tyres. There is a decrease in overall boot capacity due to the housing of the lithium-ion battery, though it remains a very useable size.
From the driver’s seat the overall cockpit layout is familiar with the addition of an ‘eDrive’ button to the base surround of the automatic gear selector. This button can be used to select electric-only mode, which, battery charge permitting, is capable of a driving range of 22 miles and can reach a top speed of 75mph. BMW’s engineers say they believe this range is acceptable, based on existing customer driving data that showed average daily commutes. Consideration was also given when determining the size of the high-voltage battery required and how it could impact overall weight and balance of the car. Should the battery’s charge level be depleted, or you wish to preserve it prior to entering a congestion charge zone for example, the ‘Save’ mode keeps the battery at a constant state of charge above 50 per cent. Should it already be below this level the engine will generate enough energy to charge the battery up to 50 per cent capacity.
Despite the presence of the TwinPower petrol engine, it is the electric motor that is the default choice every time the car is started – providing there is some charge in the lithium-ion battery – while the Driving Experience Control defaults to Comfort mode. Engaging ‘Drive’, the car silently moves away and wastes no time in getting up to speed, although not with quite the same urgency that can be experienced in the i3. In comparison to the i3, however, there is less of a high-pitched whine from the electric motor – in fact the noise level in the cabin remains quite low during this mode. With more than 95hp and 184lb ft of torque (250Nm) at your disposal, performance is more than acceptable for urban use and heavy throttle pressure needs to be applied in order for the combustion engine to spool into life. When it does the integration of the two motors is quite smooth. On poorer road surfaces that generate higher levels of road noise the activation of the combustion engine would almost go unnoticed were it not for the rev counter rising up from its indicated 0rpm in EV mode. The car’s iDrive screen can also be configured to display precisely which elements of the hybrid drivetrain are being used in real time.
What was less refined in the pre-production prototype we drove was the roll-on throttle when the combustion engine is in use, especially immediately following a regenerative braking period. It lacked the smoothness that one would expect, though engineers were keen to point out that this is a known issue that is expected to be eradicated come series production through software enhancements.
In the broader sense the driving dynamics are very impressive even in this early development prototype, driven around the winding canyon course at BMW’s Testing Centre in Miramas on the outskirts of Marseille. With ‘Sport’ mode selected, both motors are engaged simultaneously delivering a level of performance that is closer to what would normally be achieved with the company’s six-cylinder engines. This ‘eBoost’ also harvests energy under braking to feed back into the battery – unlike ‘Eco Pro’ mode, which enables a coasting function off throttle to help maximise driving range. The car has a planted feel even though it carries an additional 165kg in hybrid hardware. Engineers at the event suggested that the overall balance of the car could be very close to BMW’s usual 50:50 weight distribution.
Given the popularity of diesel engines in the current market, particularly the 320d, the plug-in hybrid will already face an uphill battle to win over the hearts and minds of buyers. A two-hour charging time from a dedicated domestic wallbox (or four-and-a-half hours at a public station) shouldn’t deter too many; however it is the CO² emissions that are likely to pique the interest of business and company car buyers. At just 50g/km it attracts a low five per cent BIK rate and also avoids London’s congestion charge. Just where BMW decides to pitch its pricing for the plug-in hybrid remains to be seen, though it will most certainly carry a premium over both entry-level petrol and diesel models. However, as BMW’s battery and eDrive technology advances, by the time the series production begins the price gap may not be quite as big as it is with the ActiveHybrid 3 at present.