Abstract
Keywords
Compressor surging, Tongue, Blade Passing Frequency (BPF), Synchronous Noise, VGT(Variable Geometry Turbocharger)
Abstract
This paper introduces the improvement process for the several noises occurred in the turbocharger of diesel engines. The turbocharger noises introduced in this paper approximately can be divided into five kinds, that is, synchronous noise, sub-synchronous noise, BPF noise, exhaust pipe ring noise and compressor surging noise. The synchronous noise is the same frequency as turbo rotation speed and sub-synchronous noise is the lower frequency than turbo rotation speed. These could be reduced by the rotor shaft unbalance improvement and bearing clearance optimization. The complex noise between BPF and exhaust pipe ring noise was reduced by the stiffness reinforcement of exhaust system and the structure modification of the turbo charger housing. The compressor surging noise at sudden acceleration pedal release was reduced by the bypass valve control using engine ECU and EGR valve control.