Knock control system

• US 4,528,955 A
• Filed: 01/17/1983
• Issued: 07/16/1985
• Est. Priority Date: 01/19/1982
• Status: Expired due to Fees

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Sugiura, Noboru
• Primary Examiner(s): Cox, Ronald B.
• Application Number:
  US06/458,324
• Time in Patent Office: 911 Days
• Field of Search: 123/425, 123/435, 73/35
• US Class Current: 123/406.37
• CPC Class Codes: F02P 5/1526 with means for taking into account incorrect functioning of the pinking sensor or of the electrical means
• CPC Class Codes: F02P 5/1527 with means allowing burning of two or more fuels, e.g. super or normal, premium or regular
• CPC Class Codes: Y02T 10/40 Engine management systems

Abstract

A gain control system comprising a gain variable amplifier for amplifying an input signal linearly, a gain control circuit for producing a gain control signal for controlling the gain of the amplifier on the basis of an output signal of the amplifier, and a gain control signal controller for controlling the gain control signal to prevent the gain of the gain variable amplifier from changing abruptly. A signal for controlling the ignition timing is produced by a comparison of a background level of engine noise with the output of a knock sensor. The background level signal is produced by a first integration circuit having a time constant of T₁. The gain of the output signal from the knock sensor is controlled by an output signal from the background level sensor which is integrated by a second integration circuit having a time constant of T₂ in which T₂ >T₁.

Claims

1. A knock control system comprising:

a knock sensor for detecting an engine knock signal;

a gain variable amplifier coupled to receive and amplify a knock detection signal from said knock sensor;

first integrating means having a first time constant and coupled to receive an output signal of said gain variable amplifier to provide an integrated output signal;

a gain control circuit for delivering a gain control signal for controlling gain of said gain variable amplifier on the basis of the level of said integrated output signal; and

second integrating means having a second time constant larger than said first time constant for integrating said gain control signal delivered from said gain control circuit prior to application to said gain variable amplifier.

2. A knock control system according to claim 1, further comprising a comparator circuit for comparing the output signal of said gain variable amplifier with said integrated output signal from said first integrating means so as to provide a spark timing control signal to an ignition control device based on said comparison of said integrated output signal and the output signal from said automatic gain control circuit.