| 摘要 |
The invention relates to a control mechanism 5 related to a four-stroke combustion engine, of the type having, for each working cylinder 2 and communicating therewith, a prechamber cylinder 3, the prechamber piston 4 of which under control of the control mechanism 5 is brought to perform a cyclic movement between an inner and an outer dead centre position. Of these, the inner is independent of the partial load of the engine and the outer dead centre position is controlled in dependency of the partial load of the engine, so that the compression pressure in the working cylinder 2 and the corresponding prechamber cylinder 3 is approximately constant. The excellent feature of the invention is that the control mechanism 5 comprises an axle 6, operatively connected to the crankshaft of the engine and axially displaceable in dependency of the partial load of the engine, and adapted to rotate with half the rotational speed of the crankshaft. The axle 6 has a cylindrical portion 8, the centre-line 9 of which forms an angle with the axle 6, that is, such that during the rotation of the axle 6, the centre-line 9 generates the mantle surface of a cone, and a rotatably sleeve 11, secured against rotation and rotatably journalled on said cylindrical portion 8. Said sleeve 11 has a cam 12 with axial extent with which cam 12 the prechamber piston 4 is operatively connected, either directly or via a link mechanism 13. The operative connection is such that by displacement of the axle 6, the relative movement between the piston 4 and the cam takes place along a predetermined, straight trajectory which slopes relative to the centre-line 9 at an angle which is equal to that which the centre-line 9 forms with the axle 6, but opposed, so that, as the axle 6 has a predetermined rotational position, said trajectory 14 is approximately parallel to the axle 6 and at the same time thus defining the inner dead centre of the prechamber piston 4 which is independent of the partial load of the motor. As the axle 6 has an opposed rotation, the trajectory 14 has maximum slope relative to the axle 6, thereby defining the outer dead centre of the prechamber piston 4, dependent of the partial load of the engine. <IMAGE> |
