On cars, old, new and future; science & technology; vintage airplanes, computer flight simulation of them; Sherlockiana; our English language; travel; and other stuff
DIESELS AND Daimler-Benz go way back. In fact, the world’s first passenger car powered by Rudolf Diesel’s compression-ignition engine was the 1936 Mercedes-Benz 260D. The newly introduced GLK250 BlueTEC 4Matic continues this tradition in a highly efficient mid-size SUV.
I confess, my first thought about luxury car diesels is to recall past Editor of R&T Tony Hogg, rest his soul, who once said, “They offer rich people the opportunity to slum at truck stops.” However, diesel efficiency gets my attention.
Hearing that this mid-size GLK250 is EPA-rated at 24 City/33 Hwy/28 Combined puts things in perspective. The GLK is just a little smaller than my Honda Crosstour (www.wp.me/p2ETap-9S), the EPA numbers of which are 21/29/24, respectively.
I drove a GLK250 recently and, without buyer’s regret for my Crosstour, I can certainly appreciate the GLK’s attractions. Like any Mercedes, it’s well executed and beautifully finished. Styling is a subjective thing, and, in fact, I find a little too much action, especially in its front three-quarter view. Otherwise, it’s trim, tidy and utile.
The GLK comes close to passing the Simanaitis In/Out Test, though I must either scrape a litttle hair or exercise vertebrae a bit much (unlike in the Crosstour, which doesn’t have the SUV step-up). Mercedes marketers tell me that three in four of GLK buyers don’t have children at home—it’s their friends who get to enjoy the car’s more than adequate rear accommodations. (Once seated, there’s more headroom in back than in the Crosstour.)
Here in North America, the GLK250 BlueTEC comes only with Mercedes’ excellent 4Matic all-wheel drive. Price for a base model, fairly austere by Mercedes standards, but including $905 destination and delivery, is $39,495. Plenty of Optional Packages take prices beyond $50K (and make the GLK250 look like the photos here). Figure it’s three-quarters of the way between a gasoline-fueled GLK350 and its 350GLK 4Matic counterpart.
Being a genuine SUV, the GLK is capable of off-road shenanigans that 95 percent of its owners will never experience. The only tradeoff I sense in this regard is a rather high step-up accompanying its 7.9-in. ground clearance (see In/Out Test above).
The GLK250’s powerplant is a 2.1-liter two-stage turbocharged inline-4 BlueTEC diesel. The BlueTEC moniker identifies Selective Catalytic Reduction, downstream injection of an on-board AdBlue urea solution for NOX control. The two turbos are in series, a small high-pressure unit at the exhaust manifold (for quick spin-up), its larger low-pressure counterpart located farther downstream.
I asked specifically about “clean diesels,” because generally these are no cleaner than their average gasoline-fueled competitors. Mercedes tells me that GLK250 BlueTEC is a ULEV, as in Ultra Low Emissions Vehicle, which is impressive. Plenty of diesels are mere LEVs. None to my knowledge are SULEVs, as in Super. By contrast, scads of gasoline cars are, including lots of non-hybrids (http://goo.gl/TQ1dr).
The GLK250’s 369 lb.-ft. of torque gives it plenty of grunt in any accelerative challenge. Mercedes suggests a 0-60-mph time of 7.9 seconds. Typical of the best of modern diesels, there’s very little recognition of compression-ignition, except in these extreme calls for torque—or when waiting at a light with the window down next to other cars.
Diesels are an interesting phenomenon. In Europe, they’re half the vehicle fleet, at least in part because of governmental actions with motor fuel taxation. Here in the U.S., diesel fuel gets no tax break and has to compete with jet fuel, home heating oil and other uses for middle distillates. Plus, our refineries are optimized for cracking the middle of the barrel to extract higher distillate, namely gasoline.
There’s also the NOX/particulate conundrum: Higher temperatures for a diesel reduce soot, but increase NOX. Optimize compression-ignition for low NOX, and there are more particulates. As the risk of being tongue-twisty, even the Europeans are becoming particularly particulate-picky.
With its enhanced diesel technology, though, the GLK250 BlueTEC offers an excellent way to optimize that barrel of petroleum. ds
© Dennis Simanaitis, SimanaitisSays.com, 2013