METHOD AND DEVICE AT A COMBUSTION ENGINE WITH VARIABLE GEOMETRICAL COMPRESSION RATIO

摘要

The invention relates to a method and to an arrangement pertaining to internal combustion engines in which each cylinder (1) communicates with a second cylinder (4) that includes a movable piston (5), by means of which the volume of the combustion chamber (3) can be varied. The movable piston (5) is connected to a double-acting hydraulic piston (7) in a hydraulic cylinder (8), which communicates with a pressure source (15) through the medium of an electromagnetically controlled directional valve (13). A microprocessor (20) controls the valve (13) in response to the position of the engine crank angle and load, and closes the valve to lock the movable piston (5) in a position depending upon the value of said parameters in its cylinder (8) during the compression stroke.