In the meantime, the VTG technology is already applied in petrol engines. It was left up to now to the diesel engines because their exhaust gas temperatures are lower. Now the materials of the shifting mechanism are designed partly also by liquid cooling for higher petrol-exhaust gas temperatures. With it these engines also receive turbochargers which produce a lot of boost pressure from the exhaust gas already at low revs. If this technology is combined electronically with all other measures of the engine management and the constructive interpretation, the charge technology will not be left - like with the diesel - only to especially sporty vehicles. The engine already pulls with more power in the lower speed range if you hit the accelerator pedal as compared to an aspirating engine. The accelerator pedal response time also improves.

Already the carburetor technology teaches us that a restriction raises the aerial speed. This principle is applied for the charger with variable turbine geometry.Guide vanes arranged around the turbine wheel can all be adjusted by a twistable ring at the same time and almost infinitely variable in their incline during the engine run. Thereby the exhaust gas flow onto the turbine wheel changes. The restriction of the exhaust gases brings more flow speed and with it more pressure on the suction side in this operational area. In addition, the blades of the turbine wheel are touched further outside from the flow, raising the efficiency once more.

Up to now there was a boost pressure control. The charger was designed for a higher boost pressure than maximally needed by the engine. If the pressure became too large in certain working conditions, a bypass was opened and the exhaust gas flew partially round the turbine directly into the exhaust system. Now this complete equipment is obsolete and the charger becomes smaller. 05/07