Abstract:
Embodiments herein relate to a rotary attachment of a power driven garden tool, which rotary attachment (100) comprises a core member (110) having a cylindrical configuration and an envelope surface (111). The core member (110) is arranged to be rotatably coupled to a rotary attachment receiving portion of the power driven garden tool, so as to be rotatable about a central longitudinal axis of rotation (112). The rotary attachment also comprises a working tool (120), attached to the core member (110) so as to rotate therewith. The rotary attachment is characterized in that the core member (110) comprises at least one air gap providing element (115) extending between two axially spaced apart positions along the envelope surface (111) of the core member (110).
Abstract:
A crankcase-scavenged two-stroke engine (1) having a cylinder (9), a reciprocating piston (7) movable back and forth in the cylinder (9), and a conduit (21) ported by the piston (7) for supply of additional air into the interior of the cylinder (9) for the scavenging. The engine has an automatic decompression valve (30) for reducing compression in order to facilitate starting of the engine (1), said decompression valve (30) being connected to a combustion chamber (13) of the engine (1) and being closed by underpressure periodically created in a section of the engine (1) when the engine piston (7) is moving back and forth, said section including the additional air conduit (21), said decompression valve (30) being connected to the additional air conduit (21) by an underpressure conduit (37) having a check valve (38) for preservation of the underpressure so as to keep the decompression valve (30) closed when the engine (1) is running, and a bleed conduit (45) for eliminating the underpressure within a few seconds after the engine (1) has stopped so as to open the decompression valve (30).
Abstract:
An internal combustion engine (1) may include a combustion chamber (41) into which a mixture (40) of fuel and air is supplied, a spark plug (50) disposed proximate to the combustion chamber (41) to ignite the mixture (40) by generating a spark such that ignition of the mixture drives a piston (6) operably coupled to a crank portion (12) of the engine (1), a speed sensor (102) configured to determine engine speed, and an electronic control unit (100) configured to control operation of the spark plug (50). The electronic control unit (100) may be configured to initiate a speed limitation operation in response to engine speed reaching a cut out speed threshold and to control ignition timing within an operating band (320) of ignition angles prior to engine speed reaching the cut out speed threshold. The speed limitation operation may include skipping application of sparks. The electronic control unit (100) is further configured to apply a changed ignition angle (330) relative to the operating band (320) for first at least one spark initiated after the speed limitation operation.