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World Premiere Of The Mercedes CLS 350 CGI
Posted 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.  Read on for photos of the new Mercedes CLS 350 CGI as well as the new CGI injection system, and check out the press release 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.


Mercedes-Benz CLS 350 CGI Studio Shot Front and Side View
 
World premier of the Mercedes-Benz CLS 350 CGI
     
Mercedes-Benz CLS 350 CGI Studio Shot Rear and Side View   World premier of the Mercedes-Benz CLS 350 CGI
     
Mercedes-Benz CLS 350 CGI Studio Shot View of Hood   World premier of the Mercedes-Benz CLS 350 CGI
     
Mercedes-Benz CLS 350 CGI Studio Shot Engine View   Mercedes-Benz CLS 350 CGI: World premiere of an innovative direct petrol injection system
     
Mercedes-Benz CLS 350 CGI Studio Shot Engine View   Mercedes-Benz CLS 350 CGI: World premiere of an innovative direct petrol injection system
     
Mercedes-Benz CLS 350 CGI Studio Shot Engine View   Mercedes-Benz CLS 350 CGI: World premiere of an innovative direct petrol injection system
     
Mercedes-Benz CLS 350 CGI Engine Control Unit   In the interests of the shortest possible electrical paths the engine control unit is centrally located above the intake tract and is integrated into the engine design.
     
Mercedes-Benz CLS 350 CGI Direct Petrol Injection System   Mercedes-Benz CLS 350 CGI: World premiere of an innovative direct petrol injection system
     
Mercedes-Benz CLS 350 CGI Exhaust System   To reduce nitrogen oxide emissions, Mercedes-Benz has adopted a two-part strategy. This comprises, firstly, dual electrically controlled and cooled exhaust gas recirculation. Secondly, it also comprises two underfloor NOx storage-type catalytic converters.
     
Mercedes-Benz CLS 350 CGI Direct Petrol Injection System   Mercedes-Benz CLS 350 CGI: World premiere of an innovative direct petrol injection system
     
Mercedes-Benz CLS 350 CGI Direct Petrol Injection System   Mercedes-Benz CLS 350 CGI: World premiere of an innovative direct petrol injection system
     
Graphical Overview of Mercedes-Benz CLS 350 CGI Direct Petrol Injection System   Injection system of the direct-injection V6 petrol engine
     
Graphical Overview of Mercedes-Benz CLS 350 CGI Exhaust System   CLS 350 CGI: exhaust gas aftertreatment system
     
Parts taken from Mercedes-Benz 350 CGI Direct Petrol Injection System   Mercedes-Benz CLS 350 CGI: World premiere of an innovative direct petrol injection system
     
Mercedes-Benz 350 CGI forged crankshaft with four bearing points   V6 engine: The forged crankshaft has four bearing points.
     
Mercedes-Benz 350 CGI camshaft adjuster   V6 engine: The variable camshaft adjuster is driven by means of a double chain and braced pairs of gears.
     
Graph showing the Mercedes-Benz 350 CGI power curve   Mercedes-Benz CLS 350 CGI: World premiere of an innovative direct petrol injection system




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.

Copyright © 2006, DaimlerChrysler AG

 

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