50cc Two-Stroke Engines for Mopeds, Chainsaws and Motorcycles with Catalysts

4 different engine concepts with Catalyst have been developed in regard to pollutant emission, fuel efficiency and performance. Despite the wide power range from 1,2 HP to 12 HP and the different applications of these engines to Mopeds, Chainsaws and Motorcycles, the problems to solve have been similar. Internal measures such as optimized carburetion, cooling, piston shape and clearance, scavenging and tuning of the exhaust must enable the engine to run on the lean side. This is imperative to supply sufficient oxygen for the exothermal reaction and to keep the energy to be converted in the Oxidation Catalyst at a minimum. Secondary measures have been taken to shorten the Catalyst's light-off and to keep the temperature range in limits.