Knock detector for IC engine

摘要

The detector contains a knock sensor (1), an amplifier (2) and a filter (3) whose frequency characteristic is matched to an anticipated knock signal. The sensor output is fed to the filter via the amplifier. The filter output drives a first threshold switch (4) which has a hysteresis characteristic. The gain of the amplifier (2) is controlled according to its output via a rectifier (7) and an integrator (8). Alternatively, the amplifier output drives the integrator via a second threshold switch with hysteresis. The first threshold switch's output circuit contains a switch which is closed when the crankshaft angle is that for which knock is expected.