Innovative Solutions for the Use of Catalytic Converters in Hand-Held Engine-Powered Equipment under Severe Conditions

For performance and weight reasons conventional two-stroke engines have mainly been employed with hand-held power equipment to date. Because of the design principle, these are affected by high scavenging losses in the range of 20 to 30 per cent of the drawn-in fresh charge mass. The increasing introduction and tightening of thresholds for pollutant emission therefore require new technologies and solutions.

The development and the design of retrofit mufflers with catalyst for hand-held power equipment (especially chainsaws and power cutters) are introduced in this report.

Two different muffler concepts have been developed to be ready for serial production. The first muffler concept is specifically customized for peripheral conditions of chainsaws with two-stroke engine. The second muffler concept satisfies the specific requirements of power cutters with two-stroke engine.

Both developments show that the legal requirements in terms of exhaust gas emission and permissible temperatures can be satisfied even for existing power equipment without expensive redesigns through suitable designs of mufflers with integrated catalysts.