The unspoken word hanging in the air over the 2016 Range
Rover Td6 and Range Rover Sport Td6: still.
Range Rover, the luxury SUV imprint of Jaguar Land Rover
(JLR) and currently a brimming fountain of Yankee cash, is still following
through with its plan to offer diesel powertrains to the U.S. market. This,
despite the recent unpleasantness known as Dieselgate, Volkswagen’s
emissions-cheating scandal.
Talk about climate change. Five years ago diesel was the
great green hope, a conventionally handled fuel with about 20% higher fuel
economy and lower CO2 emissions. With low-sulfur fuel and post-combustion
urea-injection systems to reduce NOx (nitrogen oxides), diesel light-duty
vehicles could pass even California’s stringent tailpipe tests.
Today, thanks to VW, diesel’s brand is in disgrace. Meet
your new spokesman: Jared.
The good people of JLR understand the timing of their push
is less than optimal, but they note heavy industry doesn’t turn on a dime. They
make the case, reasonably, that there remains a cadre of unserved Jaguar and
Land Rover/Range Rover clients who prefer the range, durability, ready torque
and efficiency of diesel.
We’ll see. Range Rover clients can now order either truck
with a 3.0-liter turbodiesel V6 (254 hp at 4,000 rpm and 440 pound-feet of
torque at 1,750 rpm). The optional diesel will continue across the JLR’s
lineup, including the keenly awaited Jaguar F-Pace crossover.
For them, the Td6 puts up some pretty persuasive numbers.
Example: The Td6-powered Range Rover gets 32% better fuel economy (EPA combined
fuel economy rating of 25 mpg) than its petrol V6-powered twin.
I interviewed JLR’s hushed, oily gyre under the hood of both
Range Rover and Range Rover Sport, on and off-road, around Sedona, Ariz., and
its next-generation transparency was remarkable. Not only can’t you tell it’s a
diesel; you can hardly tell it’s on.
The throttle pickup is nearly identical to JLR’s feisty
supercharged six’s. On the highway, a warm warble soars from under a stamped
right foot, very like a gasser, and nothing but serene forward thrust.
Milled from compacted graphite iron, the Td6 boasts a
super-solid construction (deep skirt, through-bolted, load-bearing oil sump)
designed to attenuate diesel-y noise and vibrations. The engine is carried by
fancy dual-isolating mounts.
To outwit diesel’s famous knock, the Td6’s injection cycle
comprises multiple injection events, with fuel spritzes timed to interfere with
the initial detonation’s pressure wave. Other emoluments include acoustic
windscreen glass and noise-dampening firewall design.
These exertions are necessary primarily due to the vehicle’s
standard (and mandatory) start-stop function. Start-stop is demanding for
diesel engines, because it is that first half-second that sees the big spike in
transient rocking, when a heavy crank gets spun up against all that
compression.
Taming this shuddering has left the Td6 RR an overstuffed,
deeply hushed product otherwise. When the engine lights again, you feel the
barest frisson through the aluminum-intensive frame, and hear the faintest
thrum, as if you were in the wheelhouse of a tugboat and somebody on the
fantail started using an electric razor.
It’s all pretty marvelous. So let’s call this application of
Rudolf Diesel’s principles what it is: the technical high point of
combustion-ignition in passenger cars, the beginning of sunset.
Even before VW’s betrayal, there were good reasons to doubt
the long-term prospects of diesel fuel in the American passenger-car fleet, now
lingering at about 3% penetration. First, in an age of historically low
gasoline prices, diesel fuel prices have trended stubbornly high, an artifact
of limited refining capacity and demand from the commercial-trucking sector in
a growing economy.
Nationally in January, a gallon of on-highway diesel
averaged $2.21 compared with gasoline’s $2.03, according to the U.S. Energy
Information Administration (eia.gov). Taxes on gasoline and diesel average
about the same: 22%. The price difference just doesn’t want to go away.
Second, diesel powertrains come with a price premium, due
primarily to the aforementioned 50-state legal emissions controls, including
exhaust treatment with Diesel Emission Fluid (DEF). However, in the case of
these two new Range Rovers, the price difference between gas and V6 turbodiesel
version ($1,500) is painlessly absorbed into the overall cost of the luxury
vehicle.
Third, which I believe is the nail in the coffin: Increased scrutiny
by European regulators, who have for years waved past auto makers’
less-than-clinical test results.
It would be hard to overstate European indignation over
Dieselgate and the gaming of emissions tests by auto makers generally. In
response, the EU Parliament is hammering out new Real Driving Emissions (RDE)
requirements, whose purpose is self-explanatory: to take the self-reporting and
bench biases out of emissions tests.
That, as any engineer can tell you, is a vastly more
stringent standard, and a game changer. VW’s diesels (Audi and Porsche are now
also implicated) couldn’t pass such standards as there are without weaseling,
allegedly.
As of September 2014, the Euro 6 rules for light-duty
passenger cars include a NOx standard of .08 milligram per kilometer.
Mind you: It’s not that auto makers cannot technically make
any number the regulators put up. It’s only doubtful they can do it in a way
that doesn’t cost them money.
source: http://www.marketwatch.com/story/range-rover-td6-a-last-gasp-for-diesel-2016-01-09
by Dan Neil
http://www.boscheuropean.com
