Engine controlling device

An engine controlling device comprising in combination:

• knocking detecting means which detects pressure variation in a combustion chamber of the engine or vibration resulting from the pressure variation, and discriminates a knocking state;
• operating and controlling means responsive to said knocking detecting means and adapted to generate a feed-back control output signal for controlling at least one operational parameter of the engine, which is influential in occurrence of the knocking, such that the knocking state is optimized;
• said feed-back control signal having a level which decreases at a predetermined rate when said operating and controlling means is supplied by said knocking detecting means with a knocking signal indicating an occurrence of knocking, and which increases at a rate lower than said decreasing rate when said operating and controlling means is not supplied with said knocking signal;
• and
• means for detecting a transitional driving condition of the engine and for controlling said operating and controlling means during the transitional driving condition such that the operating and controlling means generates a forced control output signal regardless of said feed-back control output signal derived from the knocking state, said forced control output signal controlling said at least one operational parameter of the engine, in the direction in which the knocking state is avoided so that a weak knocking state is maintained.