The baffle silencer uses the principle of the reflective silencer. In this case, the highs and lows of a sound wave are superimposed, thereby eliminating the sound. The silencer has a broadband effect, but is particularly effective at low frequencies.
Since the exhaust gas is directed through several throat tubes and chambers, it is accompanied by a higher loss in pressure. However, when used as an integral solution in combination with an SCR catalytic converter, which separates pollutants in the exhaust gas, it has the positive effect that the turbulence created in the chambers can be used to achieve better mixing during urea injection thanks to the targeted placement of the silencer. The urea is necessary for the chemical reaction in the catalytic converter.
The combination of the two systems (KeSS research project) results in shorter installation lengths for the mixing sections and higher conversion rates when the urea reacts with the SCR combs. Since no mineral wool fibres are used in this type of silencer, it can be placed in front of catalytic converters or exhaust gas heat exchangers without any problems.
In this way, the sound energy, which is highly energetic especially in the range of engines’ ignition frequency, is reduced as early as possible. This reduces the stress on downstream components, such as catalytic converters, and minimizes sound radiation from them.