Leistungsverbesserung von Dieselmotoren durch variable Ventilsteuerung

Autoren

T. Tomoda, T. Ogawa, H. Ohki, T. Kogo, Dr. K. Nakatani, E. Hashimoto, Toyota Motor Corporation, Japan;

Jahr

2009

Druckinfo

Fortschritt-Berichte VDI, Reihe 12, Nr. 697

Zusammenfassung

In this research, the effect of variable valve timing and lift was studied to improve thermal efficiency of a diesel engine, while maintaining low engine-out emissions. At high load conditions, early closing of one intake valve to the other or early intake valve opening realizes an enhancement of actual swirl motion without increased pumping losses, and retarded intake valve closing reduces the effective compression ratio, which both result in an increase of EGR ratio and an advanced fuel injection timing. Consequently low NOx formation and an improved thermal efficiency can be achieved simultaneously. At low load conditions, heat release is small and fuel is dispersed with swirl because of the small fuel injection quantity, therefore increasing the effective compression ratio by early intake valve closing is effective to reduce HC.

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