Noise Distribution of the Internal Combustion Engine

Abstract

Use noise and vibration measurement and analysis system for diesel engine noise and vibration testing and spectrum analysis.Draws the following distribution:Engine noise level mainly concentrated in 400Hz-2000Hz in the normal operating conditions, the noise value of each measuring point appear a peak at about 800Hz.Intake noise is important source of noise and the noise values of the point 9 (near the intake port) are greatest in any condition.Load is constant, the sound pressure level increases as the speed increases, and the rate of increase become small when speed is high. The vibration acceleration of air intake increases sharply and appear a peak at 400Hz, causing structural resonance.Results of this research have some reference value for vibration and noise reduction design of diesel engine. The test of engine noise and vibration 1 Test equipment and acoustic environment This test uses HEAD acoustics noise and vibration measurement and analysis system.The acoustic environment is lead to the exhaust pipe outside, do not consider the exhaust noise for whole machine test, the internal combustion engine use the water-cooled means and the air filter is not installed, so measured is the diesel whole machine surface radiation noise (3). 2 Test objects and test point arrangement (1)Test objects: a single vertical direct injection four-stroke marine diesel engines, the technical parameters of the diesel engine as shown in table 1. The internal combustion engine is directly connected to the dynamometer to measure its speed and power. Figure 1 is the test site picture. Table 1 The technical parameters of diesel