PORTLAND, OR – The Mercedes-Benz E-Class does not spark the same fiery passion among well-heeled gearheads as does the BMW 3-Series and is more likely found in the parking lot of an upscale mall or country club than at a weekend autocross event.

But give the E-Class its props: So far this year, it is outselling every car from Cadillac, Audi, Volvo, Lincoln, Buick, Acura, Infiniti and all but one Lexus (ES 300/350) and one BMW (3-Series), according to WardsAuto data.

The E-Class, accounting for 25% of Mercedes sales in the U.S., has been America’s best-selling Middle Luxury car since 2009, according to WardsAuto data, and is on pace to best the BMW 5-Series again.

Its popularity stems from whisper-quiet cabins, lots of high-tech features and class-appropriate styling without being too conspicuous.

For ’14, the E-Class gets a mid-cycle freshening. From the A-pillar forward, everything is new, including the grille, sheet metal and optional light-emitting diode headlamps.

Gone is the “four eyes” look that separated the high beam from the low beam – a styling coup in the 1990s. Now, as is the case with most vehicles, one lens covers both lighting functions.

The front bumper has been rechiseled to incorporate three prominent intake ducts that alter the car’s first impression. While the previous E looked docile from head-on, the new model appears intent on retribution.

The 3-pointed hood ornament now is available only in the chrome-heavy Luxury edition while other E-Class models cradle the star within the grille for a cleaner, sportier look. It was the right move. Hood ornaments hold an important place in automotive history, but they are passé now and a danger to pedestrians.

Most significantly, the E-Class undergoes a powertrain shakeup that exemplifies the trend toward downsized engines.

Mercedes dropped the 3.0L turbodiesel V-6, which carried a $1,500 premium over the base gasoline V-6 in the E-Class sedan.

The new entry-level engine in the E250 Bluetec is a 2.1L turbodiesel 4-cyl. that undercuts the 3.5L V-6 by $500 (yes, that includes the cost of AdBlue selective catalytic reduction to scrub oxides of nitrogen emissions) and actually trumps it in sheer thrust with 369 lb.-ft. (500 Nm) of torque. That’s a staggering 96 lb.-ft. (130 Nm) more potent than the carryover V-6.

With 302 hp, the 3.5L gasoline 6-cyl. still gets off the line more quickly than the diesel I-4, which is rated at 195 hp, but the E250 never feels underpowered during test drives near scenic Mount Hood.

And the fuel-economy gain is tremendous. While the gasoline V-6 struggles in real-world driving to reach its highway rating of 30 mpg (7.8 L/100 km), the thrifty and smooth 4-cyl. diesel easily hits 40 mpg (5.9 L/100 km) on a rural route here. Even notoriously indulgent journalists broach 40 mpg, and one group rolls in at better than 44 mpg (5.3 L/100 km).

With numbers like these, it’s easy to understand why auto makers will introduce several new diesels this year in light vehicles.

Even with a slight price premium for diesel fuel over petrol, Mercedes’ new engine is supremely more engaging to drive than any hybrid around.

The 7-speed automatic transmission is an ideal match for the I-4, intuitively changing gears with little fuss, and the 2-stage turbocharger expertly mitigates lag.

With the accelerator pedal mashed, the transmission and engine, along with ample sound damping, work in tandem to quell any ruckus, while delivering a goodly amount of torque to scoot up and down this hilly terrain.

A downshift from sixth to second gear can be managed with little powertrain distress. Even paying close attention, internal-combustion aficionados are hard-pressed to identify the 2.1L as a diesel.

Across the E-Class range, a buttery stop/start system is standard for the first time.

An “eco” gauge in the central cluster turns green whenever the driver coasts, decelerates or keeps a steady pace. Consider it an e-coach for economical driving.

This 2.1L diesel, available with both rear- and 4Matic all-wheel drive, is new to the U.S. But it first was offered in 2009 in Europe, where it managed a healthy take-rate in the flagship S-Class sedan.

In the E-Class, Mercedes expects about 10% of buyers to pick the new 4-cyl. diesel (up slightly when compared with sales of the previous V-6 diesel), and about 10% will choose the 402-hp 4.6L BiTurbo gasoline V-8.

The remaining 80% of E-Class customers are expected to select the 3.5L gasoline V-6, which, like the V-8, is available in the sedan, coupe and cabriolet.

The sedan and wagon went on sale in April with the gasoline engines, and the coupe and cabriolet in June. The diesel 4-cyl. is arriving in showrooms this month in the E-Class (sedan only) and GLK cross/utility vehicle.

Also available in the lineup is the carryover E400 hybrid sedan, which pairs the 3.5L gasoline V-6 with an electric motor and is rated at 24/30 mpg (9.8-7/8 L/100 km) city/highway.

Those are decent efficiency numbers for the E-Class, but not as good as the E250 diesel, which is expected to be rated at 28/45 mpg (8.4-5.2 L/100 km) with rear-wheel drive and 27/42 mpg (8.7-5.6 L/100 km) with AWD.

It’s fair to assume the 2.1L Bluetec will eat into E-Class hybrid sales.

The kicker is the sticker: The E250 diesel carries a base of $51,400, compared with $56,700 for the hybrid.

On the inside, the refreshed E-Class receives mild design tweaks and a new instrument display.

But the real interior upgrade comes from a host of active safety technologies identical to those that will arrive in the redesigned (and more expensive) S-Class sedan this fall.

That includes surround-view camera vision, automated parallel parking, Attention Assist to prevent drowsiness, Distronic Plus tied to steering to help keep the vehicle centered in its lane, Pre-Safe rear-end collision mitigation and Brake Assist Plus to detect crossing traffic and pedestrians and provide additional stopping force when necessary.

Key enablers are new forward-facing stereo multi-purpose cameras mounted near the rear-view mirror and multi-mode radar sensors capable of seeing not only the car in front but the car ahead of that one.

What’s it all mean? That the car can behave like a person, with senses such as sight, but with faster reaction times.

Safety technology is cool, but the bigger story with the new E-Class is its outstanding 2.1L turbodiesel. Its only drawback, for showroom purposes, is its displacement: Mercedes’ customers like big engines that translate into big numbers on the trunk, such as CL63 and S550.

Dealer response surely played into naming the car E250 instead of E210.

But Mercedes knows something about marketing diesels. In the U.S., the brand sells more than all other German luxury brands, combined.

tmurphy@wardsauto.com

'14 Mercedes E250 Bluetec 4Matic Sedan
Vehicle type Front-engine, 5-passenger, 4-door AWD luxury sedan
Engine 2.1L DOHC turbodiesel 4-cyl.; aluminum block/head
Power (SAE net) 195 hp @ 3,800 rpm
Torque 369 lb.-ft. (500 Nm) @ 1,600-1,800 rpm
Bore x stroke (mm) 82.8 x 98.8
Compression ratio 16.2:1
Transmission 7-speed automatic
Wheelbase 113.2 ins. (288 cm)
Overall length 192.1 ins. (488 cm)
Overall width 73 ins. (185 cm)
Overall height 57.1 ins. (145 cm)
Curb weight 4,409 lbs. (2,000 kg)
Price as tested $68,264
Fuel economy 27/42 mpg (8.7-5.6 L/100 km)
Competition Audi A6, BMW 5-Series, Lexus GS
Pros Cons
2.1L diesel more than capable Hybrid E400 sales will suffer
40 mpg without even trying Diesel only available in sedan
Clobbers 3.5L in torque, price But gas V-6 nabs most sales