Knock control for high speed engine including a knock burst envelope follower
AssigneeDelco Electronics Corporation
InventorGlen C. Hamren
Life of this patent
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Abstract
An ignition system for a vehicle engine has a fast response knock control which generates a rectified knock sensor signal having peaks at a knock frequency in accordance with the knock induced engine vibrations and samples and holds the voltage at each consecutive peak to generate a knock burst envelope signal in which knock burst envelopes correspond in amplitude and duration to knock vibration bursts in the knock sensor signal without phase shift induced group delay. The fast response is preserved in a fast response DC noise reference and an output which provides pulses at a frequency increasing with amplitude of the knock burst envelopes.
Claims11
An ignition system for a vehicle engine of the type which may exhibit bursts of knock induced engine vibrations at a knock frequency, the apparatus comprising, in combination:
- knock sensor means responsive to the knock induced engine vibrations for generating a rectified knock sensor signal having peaks in accordance with the knock induced engine vibrations;
- trigger apparatus responsive to each consecutive peak of the rectified knock sensor signal at the knock frequency for generating a trigger signal;
- sample and hold apparatus responsive to each consecutive trigger signal to sample and hold each successive peak amplitude of the rectified knock sensor signal and thereby generate a knock burst envelope signal in which knock burst envelopes correspond in amplitude and duration to knock vibration bursts in the knock sensor signal without phase shift induced delays;
- and
- output circuit means responsive to the amplitude and duration of the knock burst envelopes in the knock burst envelope signal for deriving ignition timing for the engine, whereby knock control is enabled at high engine speed.
Dependencies are inferred from the claim text.