DI Turbo mit Scavenging – Weniger Verbrauch durch mehr Drehmoment

Authors

Dr.-Ing. Martin Brandt, Dipl.-Ing. Michael Bäuerle, Dipl.-Ing. Martin Klenk, Dr.-Ing. Michael Nau, Dipl.-Ing. Martin Rauscher, Robert Bosch GmbH, Germany

Year

2006

Summary

Fuel costs of today lead to the most important challenge for SI engines: the reduction of fuel economy. However, the actual benefits of a SI engine compared with a Diesel engine should be maintained, e.g. lower system costs and a simple exhaust gas aftertreatment which allows complying with the most stringiest emission standards. The driver expects the same driveability especially concerning engine out torque and elasticity as already obtained with a Diesel engine. This paper shows the way to realize an increase of engine torque and fast response mainly during low speed by the combined use of Gasoline Direct Injection, Turbocharging and camshaft phasing. Different valve timing values and configurations of turbochargers are evaluated by simulation of engine charge exchange. The higher engine torque and also the sufficiency of a conventional exhaust gas aftertreatment have been proved by running vehicle tests. To limit the thermal stress of the catalyst a fine calibration of the scavenging process is necessary. All functions have been implemented in a demonstration vehicle to make the benefits be felt. The described concept represents concerning cost benefit ratio a very attractive system which complies with future requirements for an SI engine regarding fuel consumption, driveability and exhaust pollutants.

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