In Europe, stage 1 of the EU directive EN 2000/14 entered into force in June/2001, putting more stringent limits on noise emission of some outdoor powered machinery categories, such as tillers (< 3 kW), lawnmowers, generators and welders, hydraulic power packs etc.
The introduction of stage 2 noise emission limits is scheduled for June/2006.

Although these noise limits do only apply to the powered equipment as an integral unit, the engine contributes obviously in a considerable way to the total noise performance.

In order to assist the manufacturers of powered equipment to reduce the overall noise emission of their products,

Honda developed and offers a wide variety of "low noise" engine types with reduced noise emission characteristics.

The development efforts have been focussed on lowering both mechanical noise as well as total noise radiation, by applying silent technologies for internal gearing and addition of sound dampening materials.

Depending on the engine model and type, the engine-specific noise emission could be lowered by 1 to 5 dB(A).

Further improvements are scheduled in view of EU stage 2 noise limits.