BMW X5 Plug-In Hybrid Prototype: We Drive Future Electric SUV

They're not here yet, but in less than two years, U.S. buyers will have a choice of at least three plug-in hybrid SUV models to choose from.

Now, we've driven a prototype version of one of them: the BMW X5 e-Drive, which will be shown as an updated concept car at this week's New York Auto Show.

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It won't arrive on the U.S. market for more than a year, but BMW is sufficiently confident in its state of development that it let a handful of journalists drive a development prototype yesterday.

Assuming the plug-in hybrid X5 arrives sometime late in 2015 or during 2016, it will face off against at least two similar vehicles: the all-new Volvo XC90 Plug-In Hybrid, and the Mitsubishi Outlander Plug-In Hybrid already in production, which is selling well in Japan and some European countries.

Our drive consisted of a dozen or so loops around the sprawling grounds of BMW's U.S. headquarters in Woodcliff Lake, New Jersey.

Standard X5, plus camo

The test car itself was a modified third-generation BMW X5, known to BMW afficionados as the "F15" after its project number.

It had been built in South Carolina, as are all X5s, shipped to Germany for modification into a plug-in hybrid, and then shipped back to the U.S. for testing.

It would have been a completely standard-looking 2014 BMW X5 if not for several patches of camouflage covering various aspects of the vehicle.

Most notable was the charge-port door on the left-front fender, which we were only allowed to photograph in its closed position because the insides were a mockup rather than a final, BMW-quality production item.

It contained a standard J-1772 socket (connected to a 3.5-kilowatt onboard charger, as we found out later).

Minimal cargo loss

Other than that, it would have been an unremarkable X5--and it would take a skillful eye to notice that the cargo deck was 1 inch higher than in a gasoline or diesel X5.

Under the floor, a 9-kilowatt-hour lithium-ion battery pack (using similar cells to those in the upcoming 2015 BMW i3 plug-in hybrid sports coupe) rode just over the rear axle, with a shallow compartment containing a 120-Volt charging cable behind it.

Like our prototype, the production version of the X5 e-Drive will forgo a spare tire, using either run-flat tires or a can of emergency sealant and inflator as an emergency measure.

The battery is cooled, when necessary, using refrigerant that loops through channels in the pack and shed their heat via the exchanger in the X5's standard air-conditioning system.

Four-cylinder X5

The powertrain dispenses with the six-cylinder and V-8 gasoline engines used in conventional X5s, and substitutes a 240-horsepower 2.0-liter turbocharged four-cylinder engine producing 255 lb-ft of torque.

That would make the X5 e-Drive the sole model in the range to use a four-cylinder gasoline engine--although every BMW exec who pointed this out also noted that the company "does not currently" offer a four-cylinder gasoline X5, or that such a model did not exist "as yet."

A 70-kilowatt (95 hp) electric motor producing 185 lb-ft of torque is located between the engine and an adapted version of BMW's standard eight-speed automatic transmission.

The electric motor replaces the transmission's torque converter, and has a clutch on either side. A large engagement clutch sits between the engine and motor, plus a smaller "creeper" clutch between the motor and transmission to allow for smooth idle creep in traffic.

Output of the combined powertrain is expected to be 270 hp or higher, and 300 lb-ft of torque or higher.

Mechanical AWD

Importantly for those in snowy climates, the standard BMW xDrive all-wheel-drive stays intact.

The xDrive system electronically controls torque distribution among the four wheels based on driving conditions, but sends power to all four wheels mechanically.

That system was used by the old Ford Escape Hybrid in its 4WD variant, but it differs from other hybrid SUVs.

The current Toyota Highlander Hybrid, for example, employs an all-wheel-drive system that drives the front wheels mechanically but uses an additional electric motor on the back axle to power the rear wheels when needed.

'Max eDrive'

As befits a standard model-line extension, the X5 plug-in hybrid resembles a conventional X5 in every way possible--including the three standard BMW drive modes: Eco Pro (for maximum energy efficiency), Comfort (the default mode), and Sport (for faster powertrain response).