Launched in Jaguar's S-TYPE saloon in 2004, Jaguar's
state-of-the-art twin-turbo V6 Diesel sets new standards in
refinement and performance. The highly efficient 24-valve engine
features advanced technologies, including the latest generation
high-pressure, commonrail, direct-injection fuel system and a
lightweight, compacted graphite iron (CGI) cylinder block.
The outstanding strength and durability of CGI means that less
material is needed than for a conventional cast iron block,
ensuring reduced engine weight and length. In fact, the new diesel
engine is the lightest unit of its type, at just 202kg. This
significantly contributes to excellent power-to-weight ratio and
fuel economy.
Other features at the heart of the engine provide the capability
to deliver high performance and excellent durability. Cast
aluminium pistons incorporate 'double wave-gallery' cooling. In
this process, oil is sprayed precisely onto the inside of the
pistons from jets in the block. The oil then flows through two
internal wave-shaped channels to help cool each piston crown. This
arrangement also has the indirect benefit of reducing piston 'slap'
noise.
Management of the engine's noise characteristics has focused
particularly on injector tick and combustion noise, which is
controlled through the use of next-generation commonrail
technology, including 'multiple-point' injection and closed-loop
injection control, which ensure that the combustion is smooth under
all operating conditions.
The fuel quantity provided by each injector is controlled by a
piezo actuator, which enables highly accurate fuel metering of up
to five injections per cycle. These features provide an extremely
fine spray of diesel fuel, which ensures the most uniform fuel-air
mixture possible, resulting in a more complete combustion process.
The 2.7-litre diesel engine achieves both high power and the
desired emissions capability.
From the outset, the Jaguar 2.7 diesel engine was designed to
meet future emissions levels. However, further advances in reducing
emissions since the launch of the
S-TYPE Diesel (2004) have been made through changes to the fuel
injection system, utilising higher injection pressures and
different injector spray patterns. The calibration of the
electronically actuated turbochargers, the exhaust gas
recirculation system and port deactivation have also been revised.
With the addition of a Catalysed Diesel Particulate Filter (CDPF),
the advanced design of the V6 engine ensures it exceeds Euro Stage
IV emissions requirements for model-year 2006 S-TYPE Diesel.
Aiding both performance and emissions is a forced induction
system, comprising twin-turbochargers with state-of-the-art
electronic actuation. Traditionally, turbochargers are vacuum
actuated, but this new form of rotary electric actuator gives a
higher degree of control, providing benefits in the areas of
emissions and transient engine performance, as well as in balancing
performance and emissions between the two cylinder banks. The
turbochargers are a low inertia type for quick, responsive, power
delivery.
The high-grade aluminium alloy cylinder heads are equipped with
four valves per cylinder and double overhead camshafts. This
combination provides optimum induction and exhaust actuation, with
attendant benefits in performance and emissions. The cylinder head
design includes a port deactivation system and pistons with
toroidal combustion chambers, producing a highly efficient
combustion capability. A low - by diesel standards - compression
ratio of 17.3:1 contributes to improved emissions quality, quieter
combustion and compatibility with the engine's unique forced
induction system. In a diesel engine, reduced compression means
less heat build-up in the piston bowl and more efficient fuel burn,
resulting in lower levels of pollutants.