System for cooling catalyzed combustion exhaust gas of hydrocarbon fueled internal combustion engines used in small power equipment and power tools

A small power equipment, the small power equipment comprising:

• an internal combustion engine,
• a short length exhaust including a catalytic converter operably connected to the internal combustion engine and a muffler outlet tube, the short length exhaust being operable to receive combustion exhaust gas from the internal combustion engine,
• an exhaust cooling system operably connected to the short length exhaust, the exhaust cooling system being operable to received catalyzed combustion exhaust gas from the short length exhaust;
• wherein the exhaust cooling system comprises:
• a cooling air guide;
• and
• a mixing chamber including an intake end, an exhaust end, at least one cooling inlet, and a swirl mixer, wherein:
• the short length exhaust is operably connected to the intake end of the mixing chamber via the muffler outlet tube;
• the cooling air guide includes an air guide panel and at least one radial rib, wherein the cooling air guide is operably connected to the at least one cooling inlet, and is operable to direct cooling air through the at least one cooling inlet into the mixing chamber;
• the swirl mixer includes a swirl vane assembly positioned around a cylindrical sleeve, the cylindrical sleeve being operably connected to the muffler outlet tube, wherein the swirl vane assembly is operable to induce the cooling air and catalyzed combustion exhaust into a vortex within the mixing chamber;
• and
• the mixing chamber is operable to facilitate mixing of the catalyzed combustion exhaust gas and cooling air to reduce a peak temperature of a combined exhaust gas.