First Drive Review
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The 3-series hybrid is refined, but a four-cylinder system would make more sense.
Like all of the German carmakers, BMW has a preference for diesel power over hybrids in the search for improved fuel efficiency. But America—a pretty huge market, as you may have noticed—is crazy for gas-electrics, as are parts of Asia, so the Bavarians have spun off hybrid versions of their mainstream sedans.
The ActiveHybrid 3—or “3-series hybrid” to those who prefer nomenclature that’s not fairly dripping with marketing goo—uses BMW’s 300-hp, 3.0-liter, turbocharged six, coupled to a ZF eight-speed automatic in which the torque converter has been replaced by a 54-hp electric motor. Add a clutch between the electric motor and the internal-combustion engine and you’ve got all of the go bits. It’s the same gasoline-electric system in the ActiveHybrid 5, and it also is being adopted for the repositioned 2013 ActiveHybrid 7.
Batteries Included
Power for the electric motor comes from a 1.3-kWh lithium-ion battery pack made from 96 cylindrical cells from supplier A123 Systems; the stack is mounted below the trunk floor. The 317-volt battery, which weighs 101 pounds with its internal cooling apparatus, also can power the electric air conditioning compressor. Feeding juice into the battery pack is the work of the electric motor, which acts as a generator during braking and coasting. A pair of conventional 12-volt batteries also is aboard; one is devoted to energizing the engine starter, the other to various other electrical systems that include the electric power steering and the brakes.
The gasoline engine and electric motor produce a combined output of 335 ponies, as well as 332 lb-ft of torque—35 and 32 more than developed by the conventionally powered 335i. However, all of the hybrid’s hardware puts it 298 pounds above a 335i sedan, and the green-leaning car’s final-drive ratio has been lengthened from 3.15 to 2.81 in search of fuel economy.
Not Slow—But Not Terribly Efficient, Either
As a result, we estimate the 3-series hybrid will hustle to 60 in five seconds flat—not slow by any means, but a tenth off BMW’s own claim for a 2013 335i automatic. (The 2013 335i auto will be recalibrated for less torque interruption during shifts compared to the 2012. We also typically find BMW acceleration estimates to be conservative.) At 33 mpg, highway fuel economy is unchanged from our benchmark 335i automatic, but city mpg climbs up two to 25. A 328i can achieve as high as 23/34. We’re curious to see what we measure in real-world driving with the hybrid.
Specifications
VEHICLE TYPE: front-engine, rear-wheel-drive, 5-passenger, 4-door sedan
BASE PRICE: $50,195
ENGINE TYPE: turbocharged and intercooled DOHC 24-valve 3.0-liter inline-6, aluminum block and head, 300 hp, 300 lb-ft; AC synchronous electric motor, 54 hp, 155 lb-ft; combined power rating, 335 hp, 332 lb-ft; 1.3-kWh lithium-ion battery pack
TRANSMISSION: 8-speed automatic with manual shifting mode
DIMENSIONS:
Wheelbase: 110.6 in
Length: 182.0 in
Width: 71.3 in Height: 56.3 in
Curb weight (C/D est): 3900 lb
PERFORMANCE (C/D EST):
Zero to 60 mph: 5.0 sec
Standing 1/4-mile: 13.6 sec
Top speed: 155 mph
FUEL ECONOMY (C/D EST):
EPA city/highway driving: 25/33 mpg
Continued…