Basic study on inset position of stack in the system with branch tubes for applying thermoacoustic silencer to multi cylinder engine muffler

We have proposed an automobile muffler that uses the thermoacoustic effect. Application of the thermoacoustic effect to a silencer was investigated experimentally in previous studies. Results confirmed that the sound pressure after passing through the stack with a temperature gradient was less than that without a temperature gradient. From these experiment results, a silencer based on the thermoacoustic effect was developed. This study specifically examined the stack installation position. The muffler of a multi-cylinder engine has branch tubes. We investigated the influence of the stack installation position of the branch tube. A branch tube has a confluence. A stack was installed on the front and back of the confluence. When the stack was installed on the front and back of the confluence, a silencing effect was confirmed. When the stack was installed on the back of the confluence, the silencing effect was effective.