2011 Mercedes-Benz E350 BlueTec Diesel 12-Month Review and Report – The Green Car Driver –

Our 2011 E350 BlueTec is a standard E350 sedan in every regard save one: the engine.  Compared to the gasser, the E350 BlueTec came with a smaller 72° V-6 3.0-liter engine, which is the same one that powered an earlier E-Class diesel in the U.S., the 2006 E320 diesel. The difference is that, today, the engine is fitted with Mercedes’ AdBlue urea-injection system that scrubs the exhaust, eliminating almost all of its NOx emissions and making the car legal in all 50 states.

While the outward appearance is similar, one drive makes the differences rather apparent.  Although the diesel only produces 210 hp, it does develop 400 pound-feet of torque between 1,600 and 2,400 rpm.  The E350 petrol variant only manages 278 pound-feet between 2,400 and 5,000 (incidentally, the diesel tops out at 4500 rpm, but that’s fairly typical for an oil burner), and, until recently, the diesel beat the E550’s massive V-8, which just got an increase from 391 pound-feet of torque to 443.

The E350 has also gotten me used to certain creature comforts as well as some safety features I thought I would never like or use that make long-distance driving safer and more comfortable.  The seats are excellent and can be adjusted to suit any need.  The massage feature (only on the driver’s seat) has everyone vying to be the driver, and features such as blind-spot detection and active cruise control are starting to become a necessity as opposed to a high-tech option.

The safety features not only protect the vehicle’s occupants but actively take measures to avoid accidents.  Mercedes has a long history of innovation in this area, starting with the safety cage, a reinforced structure, introduced to the world in 1951, that surrounds the passenger cabin with front and rear crumple zones.  Another innovation is the integration of seat belts and air bags into a common restraint system, a feature introduced in 1981 in the S-Class.  (Until that point, most people assumed that airbags would replace seatbelts completely.)  The Mercedes system would pre-tension the seat belt, thereby limiting the wearer’s movement upon impact.  Mercedes was also an early adopter of traction control systems in 1987 and developed Brake Assist (1997), a system that uses sensors to determine the need to boost braking force in order to avoid an accident if the driver is not depressing the brake pedal sufficiently for maximum stopping power.

Distronic Plus shown as engaged on central display

These systems seem downright quaint compared to what is present in our E350 BlueTec sedan.

Disclaimer: I’ve never been a fan of cruise control and believed that it would lead to a lack of paying attention on the part of drivers.  That was the case until the E350 BlueTec arrived.  While others here were exposed to radar cruise control (I recall our associate editor Basilio Alferow, after driving for several hours from New York City to New Haven,Connecticut and back on the Interstate, how he didn’t touch either the gas pedal or the brake once on the return drive and that the car did all the work of slowing down, stopping, and accelerating based on traffic flow), I was a virgin.

How active cruise control works is simple: The Mercedes Distronic Plus adaptive cruise control system uses radar sensors in the grille to adjust the car’s speed in order to maintain a preset distance between you and the vehicle ahead.  It uses two radar beams (24 GHz and 77 GHz) to cover the road in front.  The system covers a total of more than 160 yards, monitoring every movement.

Appropriately enough, I had a chance to experience the Distronic system on the very first drive.  Shortly after leaving the Mercedes factory in Sindelfingen, we encountered heavy traffic on the A81 Autobahn on the drive to Maastricht.

While Distronic works particularly well in stop-and-go traffic, and it definitely adds a layer of safety, what really matters is the Pre-Safe Brake system that uses inputs from the Distronic system.  Pre-Safe is always monitoring the road ahead, even when the cruise control system is not turned on.  If it senses an impending collision, it emits three warning tones.  If the driver doesn’t do anything (such as brake), it will initiate braking and begin to reposition driver and passenger seats (and power rear seats in vehicles so equipped) to a position that provides best protection in the event of a crash. The system also closes the side windows (this provides greater support for the window curtain airbags) and, if a rollover is possible, the sunroof is closed as well.

An Attention Assist warning

If the driver still fails to react by 0.6 seconds prior to the impending impact, the Pre-Safe Brake system initiates full-power braking.  If nothing else, this will reduce the severity of the impact and, according to Mercedes, serve as an “electronic crumple zone.”

Another feature I like, particularly given that today’s cars have nowhere the visibility that many cars had 20 years ago thanks to the thicker C pillars and bigger blind spots, is what Mercedes calls Blind Spot Assist.

The concept here is simple: radar sensors in the rear bumper monitor the space to the right and left of the car, particularly focusing on the blind spot.  If a car is detected, a warning triangle in the respective rear view mirror turns yellow.  If a car is more or less alongsode, the arrow turns red.  If the sriver puts the turn signal on, indicating a plan to move in the direction of said vehicle, the arrow blinks red and an alert sounds to warn the driver.  If the warning is ignored and the driver persists in continuing in the direction of said vehicle, the car’s Electronic Stability Program uses rear-wheel braking to nudge the car back into its lane.

Click here to continue to Page 3 – Cruising the Autobahn and Virtual Drives

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