Expanderkammaren

Expanderkammaren, Swedish for "expansion chamber," is a component found in internal combustion engines, primarily in exhaust systems. Its main purpose is to reduce noise by manipulating sound waves. The chamber is designed with specific dimensions and volume that interact with the pressure pulses from the engine's exhaust. As these pulses enter the expander chamber, they reflect and interfere with each other. This interference can be constructive or destructive, and the design aims to create destructive interference for specific frequencies, thereby canceling out or significantly reducing the noise emitted by the exhaust.

This acoustic principle is a form of passive noise control. Unlike mufflers that often use baffling or sound-absorbing materials, expander chambers rely purely on the geometry of the exhaust system. They can be particularly effective in reducing certain types of engine noise without creating excessive backpressure, which could negatively impact engine performance. The effectiveness of an expander chamber is highly dependent on its size and shape relative to the engine's operating characteristics, such as its displacement and exhaust port timing. Therefore, expander chambers are often tuned for specific engine applications.