Your servant standing in front of the astonishingly powerful, but clean and frugal C-class 250 CDI, with the new generation Diesel engine...
Of course a car show visit here in Brussels is never complete without a stop at the stand of the oldest car manufacturer in the world. The marque with the star uses several technologies to make cleaner cars. The term “BlueEFFICIENCY ” actually indicates the different measures the car builder adopts to reduce fuel consumption and CO2 emissions.
The “Bluetec” is one of these measures or technologies, used in Diesel engines to reduce emissions. On the show we saw a C-class 250 with the brand new “Bluetec” Diesel generation engines. Also a S 320 “Blue BlueEFFICIENCY” was on display. In the near future, Mercedes will make available to the public a semi-hybrid car, the S-Class 400 “BlueHYBRID ”. The car, which goes in Belgium for sale in April, and is scheduled for delivery in June, sports a V6 engine coupled with lithium Ion battery based hybrid technology for which the factory has secured not less than 23 patents.
The surprising 250 CDI BlueEFFICIENCY Prime Edition …
The 250 CDI made its Belgian debut at the Brussels Motor Show...
Since autumn last year, Mercedes-Benz is set to launch a completely new diesel engine generation, and this is the topic of this report. For its world premiere, the Stuttgart-based car manufacturer has unveiled a C-Class model with this new four-cylinder engine. In this car, the C 250 CDI BlueEFFICIENCY Prime Edition, this engine produces, with its 2.2 litres of displacement, 150 kW/204 hp and 500 Nm of torque. The performance of the car is excellent, from 0 to 100 km/h in just 7.0 seconds, on the way to its top speed of 250 km/h. Notwithstanding these exceptional performance figures, the Prime Edition only consumes an average of 5.2 litres of fuel per 100 km (NEDC), with CO2 emissions of 138 g/km. The engine – according to the factory - impresses with its eager responsiveness and smoothness of operation, which can make it a sensible alternative to the higher-displacement six-cylinder engines in future. A test of a Mercedes equipped with this engine will soon prove all this… and needless to say we look forward to it!
As can be seen also from the position of the flywheel, the dual camshaft chain drive is actually at the rear of the engine, allowing a lower bonnet and enhanced pedestrian protection...
The engine design includes a number of new developments, the likes of which can hardly be found in any other standard-production passenger car diesel engine.
Here are the most important high-tech features of the new Diesel engine, which will be found not only in the passenger cars, but even in the future Sprinter models.
• Two-stage turbocharging, ensuring high power output and optimum torque delivery.
• Fourth-generation common-rail technology with a rail pressure that has been increased by 400 bar to 2000 bar, plus a new piezoelectric injector concept, featuring direct injector needle control. This creates the ideal basis for more flexible injection timing, leading to smoother engine running, lower fuel consumption and reduced emissions.
A higher ignition pressure is achieved, with pressure in the common rail system now at 2000 bar...and direct injector needle control.
• The maximum ignition pressure is raised to 200 bar which also contributes to the high output.
• Both the oil-spray nozzles and the water pump are activated in accordance with requirements to save energy and therefore fuel. The oil pump's controllable design additionally reduces the oil flow rate – and therefore fuel consumption.
• The camshaft drive is positioned at the rear in order to enhance running refinement and satisfy the exacting pedestrian protection requirements.
The 250 CDI proudly carries the BlueEfficiency badge on the side(s).
• The engine block is made from cast iron, the cylinder head from aluminum.
• A two-part water jacket in the cylinder head ensures maximum cooling in the area of the combustion chamber plate; it is this that enables an ignition pressure of 200 bar and such a high power-to-displacement ratio.
• The cast-iron cylinder barrels have been more finely honed than in the predecessor model and as such help to improve consumption.
• To compensate for the second-order forces which are inherent to four-cylinder in-line engines there are two Lanchester balancer shafts at the bottom of the engine block running in low-friction roller bearings rather than conventional plain bearings.
• The two-mass flywheel has been specifically designed for high engine torque at low engine speeds in order to isolate the crankshaft's vibration stimuli, thereby contributing to the engine's excellent smoothness.
This host of refinements leads to a very impressive engine.
As said, we look forward to a test drive with a car equipped with this engine.
And soon we will also look in more detail at the numerous technical innovations of the S-Class 400 “BlueHYBRID...
Hans Knol ten Bensel