• A Comparative Study of Sound Pressure Level (SPL) Generated in CI DI Diesel Engine Run on Petrodiesel and Biodiesel Blends
• Author  :  K.Chandrashekara, H.Yogish, R.Srinidhi, B.P. Harsha and Pramod R Sharma
• Pages   :  208-213
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• Abstract

Engine Noise Studies are being focused to check the possibility of reducing the noise at source as a means of control. In the present study, the focus is on SPL analysis, experimental investigations on performance and emission characteristics of a CI DI engine run on petrodiesel and petrodiesel-biodiesel blends. Composite Oil Methyl Ester (COME) of Jatropha and Pongamia, Graded Coconut Oil Methyl Ester (GCOME) and Waste Cooking Oil Methyl Ester (WCOME) are blended with petrodiesel in various proportions and used as fuel in the engine. SPL analysis is carried out using Brule & Kjaer (B&K) – Type 2231 Modular Precision Sound Level Meter (SLM) along with Type 1625 Octave Filter Set which measures noise pressure level differences between use of these fuels in decibels (dB).Injection pressures (IPs), 160 bars, 180 bars and 200 bars are used. The entire 1/1 and 1/3rd octaves of the sound pressure levels (SPL) generated during the combustion process are recorded and analyzed to identify critical frequencies in Hz. Comparison of SPL between petrodiesel and petrodiesel-biodiesel blends is done at the IPs chosen and at various electrical loading conditions of the engine. Experimental results show use of bio-diesel blends generated lower SPL than neat petrodiesel at various IPs and loads. Comparisons between SPL, Brake Thermal Efficiency (BTE), NOx emissions for all the blends considered have been made. By the spectrum analysis, the dominant frequencies occurred at 1250Hz and either 1000Hz or 1250Hz for 1/1 and 1/3rd octaves respectively. Generally, the occurrence of these frequencies was dominant for the optimized blends of the Methyl Esters considered.

Keywords: SPL, COME, Octaves and Dominant Frequencies.

Article published in International Journal of Thermal Technologies, Vol.4, No.3 (Sept-2014)