Max. rpm Sc
Hello,
i found an article in the Forum about the Lysholm-Supercharger for the AMG V6. What I don't understand is : If the supercharger is driven at 3,3 times the crankshaft speed ,it runs max.6.220 x3,3 = 20526 RPM STOCK !!
Others say it runs max. about 16.000RPM STOCK...
Which statement is correct?
Kind Regards Bruno
Unlike the Roots-type Eaton blower used on the supercharged Mercedes four cylinder engines, the 260kW engine uses a very sophisticated Lysholm-type supercharger produced by IHI in Japan. Driven at 3.3 times crankshaft speed, the helical lobe supercharger develops up to 1 Bar (14.5 psi) of boost. One of its two cast aluminium rotors is Teflon-coated (it's the yellow one), and the supercharger drive is through an air-conditioning style electromagnetic clutch. Despite the high efficiency of this design of supercharger, the blower still requires 45kW to power it when the engine is at its 6220 max rpm. Of course, the blower is also then flowing a lot of air - up to 1200kg per hour of it, in fact.
In order that the supercharger could be fitted into the already tight confines of the SLK and C-class bodies, it has been mounted within the 'V' of the V6. Sandwiched between the supercharger and the inlet manifold is a reverse-flow heat exchanger for a water/air intercooling system. Aimed specifically at reducing temperature peaks (an area where Mercedes-AMG engineers believe that an air/air system can be less effective), the system has its own radiator and electric water pump. The complete supercharger and intercooler system adds only 25kg of mass - so the power/weight ratios of the two cars equipped with the upgraded drivetrain are radically improved!
The supercharger engages only as required; when it is not being driven, the intake air flows through its rotors (ie no external bypass is fitted). Supercharger operation is dictated by the Bosch ME 2.8.1 engine management system on the basis of engine speed and load. However, the supercharger, which is driven from the engine's serpentine belt, will not engage at engine speeds over 3000 rpm - if this occurred, the belt stresses would be too high. If required, the engine can develop 400Nm from 2300 rpm to 6100 rpm.
The better breathing and engagement-on-demand characteristics of the supercharger have not turned the engine into a polluting and thirsty monster. Mercedes-AMG engineers are proud that that the C 32 AMG has a NEDC combined fuel consumption of just 11.5 litres/100 km and already complies with the EU 4 emissions standard that does not come into effect until 2005.