IGNITION TIMING CONTROL DEVICE FOR VARYING COMPRESSION RATIO TYPE INTERNAL COMBUSTION ENGINE

摘要

PURPOSE:To prevent the occurrence of knocking and lowering of an output, by a method, during switching of a compression ratio from a high value to a low value or during switching of it from low value to a high value, an optimum ignition timing for a high compression ratio and interpolation calculation is made on a low compression ratio to set an ignition timing. CONSTITUTION:A compression ratio varying mechanism is formed such that an outer piston is vertically moved based on, for example, an inner piston to change a compression ratio. A compression ratio discriminating means 1 is provided for discriminating whether the compression ratio varying mechanism is in a high compression ratio state or a low compression ratio state. Further, a first memory means 2 to store an optimum ignition timing prevailing when it is in the high compression state and a second memory means 3 to store an optimum ignition timing prevailing when it is in the low compression ratio state are provided. Based on a compression ratio discriminating result, the memory means 2 and 3 are selected by a selection means 4 to control an ignition timing, and during switching of a compression ratio, interpolation calculation is made on data of the memory means 2 and 3 by means of a correction means 5 during switching to set an ignition timing.