The Range Rover Vogue's new TDV8 diesel engine builds on
learning from the widely acclaimed TDV6, used in the Discovery 3
and Range Rover Sport. Delivering substantial improvements in both
performance and refinement, its maximum power is increased by more
than 50 per cent, at 272 bhp/PS (200 kW), compared with the
outgoing straight-six diesel's 177 bhp/PS (130 kW).
Maximum torque is an enormous 640 Nm (472 lb ft). This is
maintained constantly from 2000 rpm to 2500 rpm, delivering
effortless performance even at low engine speeds. Over 400 Nm of
torque is available from just 1250 rpm - greater than the previous
engine's maximum torque of 390 Nm (288 lb ft).
Acceleration is similarly transformed, with the 0-60 mph time down
to 8.5 sec from 12.7 sec (0-100 km/h now 9.2 sec, from 13.6 sec).
The improvements continue right across the speed range. In the
crucial 50-70 mph acceleration range (80-110 km/h), for example,
the new diesel model is about 40 per cent faster. Top speed is an
electronically limited 124 mph (200 km/h), up from 111 mph (179
km/h).
Twin variable nozzle turbochargers contribute to the huge torque
of the V8 diesel, as does the relatively low 17.3:1 compression
ratio. The 32-valve engine configuration allows for smooth
high-revving, assisting performance and on-road refinement.
The engine exceeds EU4 emissions standards and fuel consumption
is impressively low considering the performance: combined average
fuel economy is 25.1 mpg (11.3 litres/100 km). This is comparable
to that of many petrol saloon cars, in a vehicle that has the
capability to cruise motorways, climb mountains, cross rivers,
carry five adults in ultimate comfort plus an enormous amount of
luggage, and has one of the highest permissible towing weights of
any vehicle.
Although sharing many technologies with the TDV6, the 3.6-litre
TDV8 has been designed from the outset to meet the refinement,
torque characteristics and off-road needs of the Range Rover Vogue.
It is not just a V6 with two extra cylinders. For example, the V6
has a bank angle of 60 degrees, while the V8 has 90 degrees - the
best configuration for a V8's balance and refinement.
As with the TDV6, the TDV8 uses a revolutionary Compacted
Graphite Iron (CGI) block, which has much higher tensile strength
than 'standard grey' cast iron, better fatigue strength than
aluminium, and extraordinary stiffness. Its overall advantages in
weight and strength mean the block can be lighter and smaller than
those of rivals, making it astonishingly compact for such a
large-capacity engine.
The block's outstanding stiffness is a major factor in the
refinement of the engine. The TDV8 is one of the world's quietest
and smoothest diesels, as well as one of the mightiest. Heads are
cast in aluminium. The overhead camshafts - two per cylinder bank -
are hollow to reduce weight, and actuate the 32 valves through
roller-finger followers and hydraulic lash adjusters. The intake
camshaft is driven by a simplex bush chain, the exhaust camshaft by
near-silent gearwheels. The intake manifold - made from lightweight
injection moulding - and cylinder heads employ Land Rover's intake
port deactivation technology, to optimise swirl across the full
engine speed range.
The new TDV8 is designed not just for day-to-day road driving
and high-speed motorway or autobahn cruising, but also for river
wading, dust, mud and the steep angles necessary for class-leading
off-road capability. As with all Land Rover products, the new Range
Rover Vogue TDV8 must be able to drive through 45-degree gradients
and traverse 35-degree side slopes, as well as wade through water
500 mm deep.
The 90-degree V8 configuration means the twin turbochargers are
sited low in the engine. At extreme angles, there is a risk that
either turbo may be below the sump level, restricting oil flow. So
a new, patent pending, vacuum lubrication system has been developed
to ensure full flow of oil at all times to the critical
turbochargers, even on the most severe side slopes. No other turbo
V8 has anything like the all-terrain versatility of the Range Rover
Vogue's new engine.
The variable nozzle turbochargers - one per cylinder bank - have
small turbine wheels, for excellent response. Their variable nozzle
design boosts not only response, but also low-end torque and
top-end power. No wastegate is necessary, improving refinement and
boosting the progressive driving characteristics of the engine.
Common-rail injection technology improves refinement, power and
economy. Fuel is injected at up to 1700 bar (more than 24,000 psi),
about 30 per cent higher than in previous-generation common-rail
fuel systems. Incredibly accurate Piezo injectors provide highly
efficient combustion, very low particulate emissions and instant
power on demand. They also reduce combustion noise, improving
refinement.
Despite the phenomenal performance, this is one of the world's
quietest diesels. Noise, at both idle and full load, is extremely
low.
"Compared with the outgoing Range Rover Vogue diesel, the new
engine is up to 75 per cent quieter, a huge improvement," says Al
Kammerer, product development director for Land Rover. "In both
qualitative and quantitative measures, the new diesel is very
similar to the V8 petrol engine - a tremendous achievement."
The noise levels are so low that Land Rover engineers had to
target other sources of engine noise normally masked by combustion
noise. Extraneous sounds are dampened by a comprehensive acoustic
system, including a glass-reinforced nylon engine cover and
sound-deadening rubber-mounted covers encapsulating the fuel
injectors, to ensure that injection noise goes unnoticed.
Given the TDV8's exceptional standards of performance and
refinement, it would be easy for people to mistake it for a petrol
engine. So Land Rover has developed a new, patented device for the
TDV8 fuel filler neck, to avoid the risk of inadvertent fuelling
with petrol.
The new TDV8 diesel engine is matched to the latest-generation
ZF six-speed automatic electronically controlled transmission,
which offers extra smoothness and response. The CommandShift
facility allows for manual gearchanges, improving the dynamic
nature of the driving experience when required. Low-range is also
provided, for extreme off-roading and heavy-duty towing.
Both the new gearbox and transfer box have a wider ratio spread
than the outgoing units. Together, these provide for a 12 per cent
lower first gear, giving better off-road control and power, while
the top gear is now 28 per cent higher, to consolidate the benefits
of the new engine's excellent refinement and economy.
This latest Land Rover diesel engine was developed specifically
for Range Rover Vogue, jointly by Land Rover and Ford engineers. It
is built at Ford Motor Company's high-tech diesel engine facility
in Dagenham, England.