To Optimise The Exhaust Gas Content

To Optimise The Exhaust Gas Content

Stuttgart, Germany, May 29, 2009 - It is the bestselling van in its class in Europe, and has lent its name to an entire vehicle category. It has repeatedly set standards in technology, safety, economy, environmental protection and performance. Now the Mercedes-Benz Sprinter is consolidating its leading position even further, pulling away from its competitors with a new generation of diesel engines, new manual transmissions and numerous other features. It is cleaner, more economical and more powerful than ever, with engines of exemplary efficiency. Accordingly the Sprinter is set to continue its success story: since spring 2006, well over 400,000 units of the current second generation have been produced, with a total of over 1.7 million units if the preceding model is included. 3.5-tonne gross vehicle weight level. This comprehensive further improvement of the Mercedes-Benz Sprinter centres on the newly developed drive train, with completely new four-cylinder diesel engines having the in-house designation OM 651 and the comprehensively re-engineered OM 642 V6 engine.

210 CDI/310 CDI/510 CDI: output 70 kW (95 hp) at 3800 rpm, max. 213 CDI/313 CDI/413 CDI/513 CDI: output 95 kW (129 hp) at 3800 rpm, max. 216 CDI/316 CDI/416 CDI/516 CDI: output 120 kW (163 hp) at 3800 rpm, max. Compared to its predecessor, the top engine variant now benefits from an eight percent increase in output and an increase of no less than ten percent in maximum torque. The V6 OM 642 engine has been comprehensively developed further, with an unchanged displacement of 2987 cc. As the only six-cylinder unit installed in a van, it likewise now meets the Euro 5 emission standard. In addition to slight increase in output, it impresses with its ten percent increase in maximum torque. 219 CDI/319 CDI/419 CDI/519 CDI: output 140 kW (190 hp) at 3800 rpm max. The four-cylinder OM 651 diesel engine is a completely new design. It only shares its overall displacement of 2.15 litres with its predecessor (to be precise: 2143 cc, predecessor 2149 cc). It has a completely different geometry, however.

While the bore and stroke were previously roughly square, the new engine is a long-stroke unit with a bore of 83 mm and a stroke of 99 mm. This allows a high ignition pressure of 200 bar, leading to increased torque, pulling power and overall performance. The compression ratio has been reduced from 17.5:1 to 16.2:1. The advantages include smooth idling even when cold, despite the undersquare configuration. The engine has a high-strength block of grey cast-iron, with deep-seated cylinder head bolts. This reduces friction and allows more perfectly cylindrical walls, which are finely honed for even lower friction. The pistons are of aluminium. Owing to the long-stroke geometry, an omega shape was chosen for the piston crown. This wide, flat crown harmonises with the long injection spray lengths of an undersquare engine. An optimised combustion process significantly reduces the untreated emissions. Owing to the long stroke, the forged, weight-optimised connecting rods are short, which is an advantage in terms of strength.

The forged crankshaft with eight counterweights rotates in five bearings. It is very low in vibrations, thereby contributing to the smoothness of the engine. The two overhead camshafts operate a total of 16 intake and exhaust valves via roller-type tappets with hydraulic valve adjustment. The camshafts are driven by a combination of gears and a short duplex chain. Great attention to detail has reduced the louder noise normally associated with gear-driven camshafts. As before, a common-rail system is used to inject the fuel. This design ensures highly precise and therefore economical fuel metering for each cylinder, as well as smooth running. The maximum injection pressure has been increased to a remarkable 1800 bar in the new engine generation. Improved, fourth-generation solenoid injectors with improved control and a seven-hole injection nozzle allow up to five injections per combustion cycle: a maximum of two pre-injections is followed by the main injection and, if required, a post-injection phase. The benefits include a gentle increase in pressure, and therefore quiet, smooth running.

The new injectors are free of leaks, therefore no additional line is necessary to return fuel. This improves thermal management of the injection system and makes it unnecessary to cool the fuel. A compact dual-plunger injection pump generates the necessary pressure in the rail, while a throttle valve regulates the charge level. The required pump output has been considerably reduced as one of several measures designed to lower fuel consumption. The developers devoted great attention to the turbocharging. This is not only of decisive importance for the rated output and torque, but also for power delivery and therefore responsiveness. In the basic 70 kW (95 hp) version, the engine is aspirated by a single-stage turbocharger with variable turbine geometry. This ensures a high level of efficiency and rapid response. In the other output versions of the four-cylinder engine, a further development of the two-stage turbocharging installed in a van for the first time in the preceding model is used. In this case a small high-pressure turbocharger works together with a large low-pressure turbocharger. The two turbines are connected in series.