Mercedes-Benz E300 Bluetec Hybrid sedanEnlarge Photo
Starting up--like many hybrids--is a silent experience. A little beep signifies that the car is "Ready", at which point you can pull away on electric power alone.
The engine soon kicks in if you press the gas pedal any harder, and thanks to the tiny electric dial it's much easier to accidentally drive at a pace where the engine kicks in. When it does, it's admirably quiet and smooth--very nearly as slick as the gasoline-powered Lexus GS 450h.
The engine also frequently cuts out at speed, allowing the car to coast--Mercedes says that the engine can cut off at any speed below 100 mph.
Even with the engine running, economy is still impressive. Officially, on notoriously optimistic European fuel tests, the E300 Bluetec Hybrid will average 54-56 mpg.
Economy figures from relatively short runs--we drove the car around 13 miles in total--and deduced entirely from the on-board trip computer must always be taken with a pinch of salt.
However, we were still impressed by the numbers we saw: At around 80 mph on the freeway, driving both into and away from the wind, the computer showed an average of 41 mpg.
By the end of our drive, with a few periods of engine-off "gliding" and some low-speed driving in EV mode, the computer was showing 44 mpg. Both are remarkable figures for a car of this size and performance, and 10 mpg higher than we achieved in our test of the Lexus GS 450h--though admittedly, the Lexus' figure was attained over a more comprehensive 100 miles of driving.
Not for the U.S...
The Lexus also offers greater performance, and a marginally smoother drivetrain--thought the Mercedes is very, very close. On the other hand, the Lexus runs on premium gasoline, currently slightly more expensive than diesel.
Really though, the biggest strike against the Mercedes is that the company has no plans to bring it to the U.S, instead intending to supply the gasoline-fueled, quicker but less efficient E400 Hybrid instead.
That's a shame, given the E300 diesel hybrid's talents. It can hardly be considered slow, yet trounces any current gasoline-hybrid luxury sedan on freeway economy--surely, an environment in which many luxury sedans need to excel.