What is the internal structure of an exhaust muffler?
2 Answers
An exhaust muffler generally consists of several parts including the exhaust pipe, connecting threaded sleeve, muffler cylinder, and cylinder core. Inside the connecting threaded sleeve, there is an oil-soaked asbestos sealing ring to prevent air leakage at the joint between the exhaust pipe and the muffler cylinder. The muffler cylinder is welded with seven partition plates, dividing it into eight muffler chambers (seven expansion chambers and one resonance chamber). The cylinder core features inverted triangular flow guide grooves and numerous small holes. Relevant information is as follows: 1. Mufflers can be categorized into resistive mufflers, reactive mufflers, and impedance composite mufflers based on their working principles. 2. Resistive mufflers primarily use sound-absorbing materials to reduce noise. The sound-absorbing materials are fixed on the inner wall of the airflow pipe or arranged in a certain pattern inside the pipe. When sound waves enter the muffler, most of the sound energy is absorbed. The advantage of resistive mufflers is their ability to reduce noise over a wide range of mid-to-high frequencies, particularly excelling in attenuating high-frequency sound waves.
With years of experience in car repair, I find the internal structure of exhaust mufflers quite fascinating. It mainly consists of several compartments or chambers, intersected by perforated tubes—meaning the tubes have many small holes. When exhaust gases flow in and out through these holes, the sound waves are either reflected back by various baffles or absorbed. The interior is also packed with sound-absorbing materials, such as fiberglass layers, specifically designed to capture sound vibrations and prevent them from escaping. The design aims to allow smooth airflow while 'eating up' the noise, much like a filter. Over time, the materials degrade, rust can clog the holes, leading to increased noise or poor exhaust flow. I recommend car owners regularly inspect the exhaust pipe for corrosion and address any issues promptly to avoid affecting overall performance or increasing fuel consumption. During modifications, some may adjust the spacing of internal baffles to alter sound levels, but care must be taken not to create excessive exhaust backpressure, which could harm engine efficiency.
