Aqua Silencer: A Review of Design, Noise Attenuation, And Exhaust Emission Control in Internal Combustion Engines

The aqua silencer is an innovative exhaust management device designed to simultaneously reduce noise pollution and exhaust gas emissions from internal combustion (IC) engines. Unlike conventional metallic silencers, the aqua silencer routes exhaust gases through a water-filled chamber equipped with a perforated tube and activated carbon or lime water filter media. The turbulent interaction between exhaust gases and water causes sound wave absorption, while dissolved pollutants — primarily carbon monoxide (CO), hydrocarbons (HC), and particulate matter (PM) — are trapped in the liquid medium. This seminar paper synthesises fifteen peer-reviewed and technical studies on aqua silencer design configurations, noise attenuation performance, emission reduction efficiency, filter media comparisons, and emerging hybrid variants. Results across studies consistently demonstrate that aqua silencers reduce exhaust noise by 10–18 dB(A) and lower CO emissions by 25–45% relative to conventional silencers. The paper further examines challenges including backpressure increase, water management, and corrosion resistance, and concludes with recommendations for standardisation and broader vehicular adoption.