An apparatus for controlling an internal combustion engine.

摘要

An apparatus (14) for controlling an internal combustion engine (12) comprises a transducer (16) which detects acoustic emissions generated by the operation of the engine, and produces an output signal. The output signal is amplified (18), rectified (20) and enveloped (22) to produce an electrical signal. The electrical signal has its direct current component removed (24) to leave the alternating current component of the electrical signal. The AC component of the electrical signal is rectified by a rectifier (26) and the mean level of the AC component of the electrical signal is measured by a measurer (28). An analyser (30) monitors the mean level of the AC component of the electrical signal and sends a feedback signal to an ignition timing device (32) of the internal combustion engine (12). The analyser (30) sends feedback signals such that the mean value of the AC component of the electrical signal lies in the region of a positive peak prior to the occurrence of preignition. <IMAGE>