Akademik Veri Yönetim Sistemi
1st International Conference on Engineering and Applied Natural Sciences, Kocaeli, Türkiye, 10 - 13 Mayıs 2022, ss.380-385
Effect of engine speed and load on raw exhaust noise was measured by using a bare engine
without any kind of muffler or exhaust device (such as after-treatment systems). The tests were conducted
in ambient conditions for minimizing noise reversion. Test engine, which is a four-stroke, four-cylinder
gasoline engine, was tested by using an active electrical dynamometer. Noise sampling rate was 44.100 Hz
during test. Frequency range of data collected with microphone in range from 2 to 20.000 Hz. The
fundamental noise frequency of the engine, which is directly related to engine speed, determined to be 100
Hz at 3000 rpm that directly corresponding to EFR. In fact, all flow and pressure wave noise peaks and
their harmonics are shifting with engine speed. Tailpipe harmonics are also effecting noise spectrum but
other noise sources (such as flow noise) have more dominant effects. As engine load increased from 0% to
100% at 2000 rpm, the noise level is increasing approximately from 114 dB to 133 dB. However, the
frequency zone of the maximum noise intensity is not affected significantly by the engine load. The
increases in the noise intensity with engine load is especially clear in the frequency range from 700 to 10000
Hz.