There is again an example of a global player in automotive manufacturing, changing his production rather quickly and thus his product line. There I remember spontaneously VW, the in a tour de force moved from pump-nozzle to common rail. Not an another word about possible fuel consumption benefits, completely redesigned cylinder heads for all diesel engines.
Water under the bridge, I know. But it is the Mercedes group currently which is satisfied not only with a radical turnaround in the design of the A-class. No, even under the sheet metal there is something going. What we did not heard all on the occasion of the introduction of the A-class 1998. The engine lying nearly pushes in an accident under the body, also nothing but benefits.
Let's make it short, all water under the bridge. The engines of the new A-class are just as upright as the front-wheel drive, transverse engines from other manufacturers. New vehicles must be compatible. In the case of Mercedes that is obviously, it fit either engines from Renault as well as those of the C-Class, even though they are mounted there of course longitudinally.
Yes, you heard it right, the smallest diesel engine with 1.5 liters displacement, soon be offered is well from Renault. The next more expensive with 1.8 liters is then from Mercedes, 30 kg heavier and has with the same performance even slightly less torque, however, in the more favorable rpm range. With the Renault engine, the belt drive is finding its way into the group finally after 50 years. 30 kg, the engine is lighter than the next following OM 651, fuel efficiency included.
Efforts are being made in the Daimler press release, the engine to praise because of its previous product success by more than 1.3 million and emphasizes at the same time,it has passed the usual Daimler tests successfully.In addition are changed two-mass flywheel, starter, generator, and several software settings according to the Mercedes-level.
Interestingly perhaps, that the uppermost of the three Mercedes diesel engines comes to 350 cc more with a bigger stroke and thus leaves a little bit the total displacement equality of the range of engines. Then there are well for the other two 16 mm too much height of the engine block, which is compensated by longer conrods. Another possible reason for the 30 kg extra weight.
Thereto fit the cylinder blocks made of cast iron and the disposition of the charge air cooler directly on the cylinder head, Daimler does not take part in although in this case would be possible still shorter induction pathes and thus more spontaneous throttle response. About the apparent step backwards to magnetic injectors of Delphi will be reported somewhere else.
Meanwhile, in turn Piezo conquers the world of gasoline engine and is impressive with its multiple direct injection and actuation without hydraulic transmission. This is not, however, beyond more than 200 bar. Again, no equality with displacements of 1.6 and 2 liters, which would be differentiated only by the charging pressure. The of course is 1.9 bar higher than for diesel engines and the cylinder blocks made of aluminum yet something more modern.
Of interest, how the Mercedes engineers want to reduce the turbo lag even further. They increase with its variable valve train in certain areas of operation the overlap and thus provide a more complete filling with cold air. If thereby also passes air into the outlet, no matter. And the extra amount the charger slows down less at a gas withdrawal.
Mercedes specifies the fuel would evaporate up to four times faster with the piezo-injectors, particularly important because of the limited time at direct injection. Meanwhile, this gasoline engines have to deal with particle formation just as the diesel engines and there the rapid evaporation is certainly a help. Furthermore, with smaller quantities per injection cycle is deposited on the walls less.
Just like VW one has studied the shutdown of two of the four cylinders and will thus also now on the market. Here too, an actuation via the valve control. To the many saving possibilities today already belonging to the standard belong the start-stop automatic which is treated somewhat neglected by many manufacturer of gasoline engines. Maybe it brings indeed more with the diesel.
In addition to the now usual energy savers such as the controlled oil pump is interesting the description of the cooling. There is circulated not at all immediately after cold start but rather when getting warm inside the engine. Presumably to avoid hot spots. Later, the large cooling circuit is included. 06/12