Engine knock control method and system with fail-safe mode

To provide for adaptive change of the operating characteristics of an engine, so that it will operate at its optimum effectiveness, just below the knocking limit, while reliably preventing knocking thereof, a computer receives engine data from respective sensors and a knock sensor (5), from which the computer calculates, based on data stored in a memory (3), operating parameters for the engine (1). The engine is, for example, an Otto-type internal combustion engine (ICE) or a Diesel engine. The operating characteristics, as computer-modified based on sensed knocking, and the modification data, are then placed into the memory to modify the basic memory content. Preferably, the memory has a basic memory content section and a programmable differential or modification section, in which algebraic constants or modifying factors are stored, based on actual experience of operation of the engine, just under the knocking limit. Thus, the stored data on which the engine operation is controlled is continuously up-dated based on actual engine operating conditions, and thereby compensating for ageing, wear and tear of parts, different fuels, or environmental conditions or the like. The computer can likewise recognize substantial deviation of the modified characteristics from the basic characteristics and, if the modifications exceed a certain limit, provide an error or malfunction output signal to an error or malfunction output indicator (9, 4) and go into a fail-safe mode.