World Premiere Of The Mercedes CLS 350 CGI
Posted by www.eMercedesBenz.com on February 24, 2006 at 8:40 AM CST
Mercedes has announced today that they will be adding a new member to
the CLS family, dubbed the Mercedes-Benz CLS 350 CGI.
The CLS 350 CGI, or Stratified-Charged Gasoline Injection if you're
not the acronym-inclined type, is the world's first vehicle sporting
a petrol engine to feature piezoelectric direct injection and spray-
guided combustion. Or in plain English, the CLS has more power than
a conventional CLS 350, all while consuming less fuel. Sound too
good be to true? Read on my skeptics.
First up are the specs. The Mercedes CLS 350 CGI is powered by a 215
kW/292 hp six-cylinder engine, producing a torque rating of 365
Newton metres at 3000-5100 rpm. That's an increase of 20 horsepower
over the conventional-injection V6 and four percent more torque. In
terms of on-road performance, the CLS 350 CGI accelerates from 0-60
in 6.7 seconds, and can reach an electronically limited top speed of
155 mph.
But as promised, despite the impressive numbers, the newest CLS also
features improved fuel economy. According to the press release,
owners can expect to see approximately 9.1 - 9.3 liters per 100
kilometers, which gives the four-door coupe a range of about 807
kilometers on one tank filling (80 Liters). For my American readers,
that comes out to about 25 mpg, an increase in fuel economy of up to
15% over the standard CLS 350.
This all sounds great, but you're probably wondering how the new
injection system works. Fear not my faithful readers, here's a small
sample from taken the press release that should give you some idea of
what's going on under the hood: "The main advantage of the CGI
engine lies in the stratified operating mode from which it takes its
name. During this mode the engine is run with high excess air and
thus excellent fuel efficiency. Now, thanks to multiple injection, it
is for the first time possible to extend this lean-burn operating
mode to higher rpm and load ranges too. During each compression
stroke, a series of injections takes place, spaced just fractions of
a second apart. This has the effect of significantly improving
mixture formation, combustion and fuel consumption. While stratified
charge operation was previously only possible in the low part-load
range, the new Mercedes direct-injection engine can still operate in
this lean-burn stratified mode at speeds in excess of 120 km/h."
Got that? Of course, that's only a small sampling of what you can
expect from the press release. Visit www.eMercedesBenz.com for
photos of the new Mercedes CLS 350 CGI as well as the new CGI
injection system, and check out the press release below for the full
details of how the new system works. Oh, and by the way - expect to
see the CLS 350 CGI hitting European shores in the second quarter of
2006.
Enjoy.
OFFICIAL PRESS RELEASE
World premiere of an innovative direct petrol injection system: Ten
percent lower fuel consumption with more output and even more driving
pleasure
Stuttgart, Feb 24, 2006
Following intensive development work, Mercedes-Benz is now presenting
the world's first petrol engine with piezoelectric direct injection
and spray-guided combustion. This 215 kW/292 hp six-cylinder engine
will enter the market in the second half of 2006 in the CLS-Class. In
the European driving cycle, this innovative injection technology from
Mercedes-Benz achieves fuel consumption improvements of ten percent
over the highly efficient V6 petrol engine with port injection and
fully variable valve timing: the figures for the CLS 350 CGI are 9.1
litres per 100 km. Thus Mercedes-Benz has succeeded in combining a
substantial increase in output with a significant increase in fuel
economy.
This pioneering injection system is another trend-setting technology
from Mercedes-Benz. It achieves much better fuel efficiency, and thus
also higher thermodynamic efficiency, than conventional wall-guided
direct injection systems. The new system will form the basis for
future engine development work in this output class.
The main advantage of the CGI engine (CGI = Stratified-Charged
Gasoline Injection) lies in the stratified operating mode from which
it takes its name. During this mode the engine is run with high
excess air and thus excellent fuel efficiency. Now, thanks to
multiple injection, it is for the first time possible to extend this
lean-burn operating mode to higher rpm and load ranges too. During
each compression stroke, a series of injections takes place, spaced
just fractions of a second apart. This has the effect of
significantly improving mixture formation, combustion and fuel
consumption. While stratified charge operation was previously only
possible in the low part-load range, the new Mercedes direct-
injection engine can still operate in this lean-burn stratified mode
at speeds in excess of 120 km/h.
When driving on main roads and motorways at largely constant speed
and with proper anticipation, the CGI engine outperforms the fuel
economy of the six-cylinder engine with conventional injection
technology by up to 1.5 litres per 100 km, a saving of up to 15 percent.
Effortless performance twinned with excellent fuel economy
Low fuel consumption and excellent power delivery are not at odds
with each other on the second-generation Mercedes-Benz direct petrol
injection model. On the contrary, the engine delivers 15 kW/20 hp
more power than the conventional-injection V6 and four percent more
torque.
Thus the V6 combines its excellent fuel economy with a level of
effortless driving enjoyment that is unprecedented in the six-
cylinder segment. The CLS 350 CGI accelerates from 0 - 100 km/h in
just 6.7 seconds and has an electronically gov-erned top speed of 250
km/h. The key figures for the new CGI engine are:
Displacement: 3498 cc
Compression ratio: 12.2:1
Rated output 215 kW/292 hp at 6400 rpm
Rated torque 365 Newton metres at 3000-5100 rpm
With a fuel consumption of 9.1 - 9.3 litres per 100 kilometres (NEDC
combined cycle), the four-door Coupé has a range of approximately 870
kilometres on one tank filling (80 litres).
Pioneering invention: outward-opening piezoelectric injectors
The most important components of this innovative direct petrol
injection system are the fast-acting, high-precision piezoelectric
injectors. It is on this invention and the way it has been translated
into series-production technology that the most important advances
associated with spray-guided combustion are based. The piezoelectric
valves have injectors which open outwards to create an annular gap
just a few microns wide. This gap shapes the fuel jet and produces a
uniform, hollow-cone-shaped spray pattern. The microsecond response
times of the piezoelectric injectors provide the basis for delivering
multiple injections per compression stroke, and thus for lean-burn
operation. By allowing flexible and efficient control of the
combustion process they play a key part in ensuring the engine's
outstanding fuel efficiency.
With the aid of simulations for the fuel mixture and the combustion
process, the pistons have been designed with special piston bowl
geometry which concentrates the lean mixture in the area around the
spark plug and prevents it from spreading out towards the cylinder
wall. The piston shape therefore also plays its part in ensuring near-
total combustion, low fuel consumption and low emissions in the
direct-injection petrol engine.
A high-pressure pump and downstream fuel rail and pressure control
valve are responsible for delivering the fuel and regulating the
quantity supplied. The peak fuel pressure in this system is up to 200
bar - around 50 times the fuel pressure in a conventional petrol
injection system.
Dual effect: low engine-out emissions and high exhaust temperatures
The Mercedes-developed combustion process featuring multiple closely
spaced injections on each compression stroke also results in smoother
operation and improved emissions performance. Measurements show that
engine-out hydrocarbon emissions in the warm-up phase are almost
halved. Furthermore, since the injection and combustion processes can
be actively controlled, it is also possible to raise temperatures in
the exhaust manifold and thus speed catalytic converter warm-up. Just
ten seconds after starting from cold, the direct-injection petrol
engine reaches an exhaust temperature of over 700 degrees Celsius.
Emissions are controlled by two close-coupled three-way catalytic
converters with linear oxygen sensor control, which goes into
operation immediately after the engine starts from cold.
To reduce nitrogen oxide emissions, Mercedes-Benz has adopted a two-
part strategy. This comprises, firstly, dual electrically controlled
and cooled exhaust gas re-circulation which, depending on engine
operating conditions, redirects up to 40 percent of the exhaust gases
back into the cylinders. Secondly, it also comprises two underfloor
NOx storage-type catalytic converters. Under lean operating
conditions, these converters adsorb the nitrogen oxides.
Periodically, during brief regeneration pulses, the nitrogen oxides
are then desorbed, reacting with other exhaust gas constituents to
form harmless nitrogen. Sensors upstream and down-stream of the
catalytic converters monitor their operation.
In addition, the new CGI engine also incorporates the same unique
package of high-tech features as its conventional-injection
counterpart. This includes four-valve cylinder heads, variable intake
and exhaust camshaft timing, a two-stage in-take manifold, balancer
shafts and intelligent thermal management with an electronically
controlled thermostat. The crankcase and cylinder heads are of
aluminium and the cylinder liners are of low-friction, thermally
resistant, lightweight aluminium-silicon alloy.
All fuel-carrying components of the CGI engine are of high-grade
steel or brass; the rails in the area of the two cylinder banks and
the housing of the high-pressure pump are of forged stainless steel.
The new CLS 350 CGI is designed to operate on sulphur-free unleaded
premium fuel and its state-of-the-art technology gives it the
potential to adapt to emissions standards of the future. In Western
Europe, the CLS direct petrol injection model will replace the
current CLS 350.
For more Mercedes-Benz news and information, visit
www.eMercedesBenz.com.