In this study, an exhaust conducting device designs and produces so that it is inquiring out the back pressure inside automobile mufflers and the actual noise generated in exhaust variable valves and study progressed in order to look into taking effects of noise as any characteristics according to the torsion spring constants of conducting exhaust variable valve within muffler.

In the experiment, exhaust variable valve designed as using CATIA V5, and it was used into experimental device as copying for exhaust system.

As experimental results, a burst of speed sections generated noise in orderof size as K2 (70 (dB)) < K3 (76 (dB)) < K1 (79 (dB)) < K4 (81 (dB)) around 2.5 seconds, a certain section turned up to maintained results of the noise changes after 8 seconds in order of size as K2 (78 (dB)) < K3 (80 (dB)) < K1 (81 (dB)) < K4 (87 (dB)) in similar tendency like burst of speed section. Therefore, it was found that whereas the constants of torsion spring tension of exhaust variable valves and the size of noise can be proportional to each other, performance characteristics for the size of the back pressures and noises inside the muffler may arise wherein these two are inversely proportional may arise too when torsion spring tension is either too small or large.

burst of speed section (BOSS), certain section (CS), exhaust variable valve (EVV), noise, back pressure.