Ignition timing control system for internal combustion engines

• US 4,539,957 A
• Filed: 09/03/1982
• Issued: 09/10/1985
• Est. Priority Date: 09/07/1981
• Status: Expired due to Term

• Current Assignee: Nippondenso Co., Ltd. (DENSO Corporation)
• Original Assignee: Nippondenso Co., Ltd. (DENSO Corporation)
• Inventors: Haraguchi, Hiroshi, Iwata, Toshiharu, Narita, Ko
• Primary Examiner(s): ARGENBRIGHT, TONY MICHAEL
• Application Number:
  US06/414,578
• Time in Patent Office: 1,103 Days
• Field of Search: 123/425, 123/427, 123/415, 123/416, 73/35
• US Class Current: 123/406.38
• CPC Class Codes: F02P 5/1523 with particular laws of return to advance, e.g. step by step, differing from the laws of retard
• CPC Class Codes: Y02T 10/40 Engine management systems

Abstract

In a system for retarding an ignition timing of the engine depending on a signal from a knock detector, the knocking intensity and the knocking frequency are discriminated in accordance with the signal of the knock detector. On the basis of the discriminated results, the system provides a small amount of retard angle for ignition timing per one knocking when the knocking frequency is low, that is, the interval between knocking signals is long and the intensity of knocking is light. On the contrary, the system provides a large amount of retard angle when the interval is short and the intensity is heavy.

Claims

1. An ignition timing control system for internal combustion engines, comprising:

a knocking detector for detecting the presence of knocks of the engine to produce a knock signal and;

an electronic control unit for controlling the ignition timing from the knock signal produced by said knocking detector, including,

first discrimination means for discriminating at least two intensities of knocks from the knock signal of said knocking detector,

second discrimination means for discriminating the interval between a knock cycle and a succeeding knock cycle, which is decided as having knocks, and

means responsive to the outputs of said first and second discrimination means for providing a small amount of retard angle for ignition timing per one knocking when said interval is long and said intensity is light, and for providing a large amount of retard angle for ignition timing per one knocking when said interval is short and said intensity is heavy.

2. An ignition timing control system comprising:

a knocking detector for dectecting an engine knocking and;

an electronic control unit for controlling the ignition timing from a detection signal produced by said knocking detector,

said control unit discriminating the intensity of knock from the detection signal,

said control unit further discriminating the interval between occurring knocks, and

said control unit still further varying the retard angle amount per one knocking in accordance with both of said discriminating results, said control unit comprising;

a knocking detector circuit for detecting the presence and absence of a knocking and the intensity thereof in response to a detection signal produced from said knocking detector, said knocking detector circuit including a rectifier circuit for rectifying the detection signal produced from said knocking detector, a knocking decision level producing circuit for producing a knocking level by integrating and amplifying the rectification signal from said rectifier circuit and adding a predetermined offset voltage thereto, and a comparator circuit for comparing the knocking level produced from said decision level producing circuit with the rectification signal produced from said rectifier circuit and generating a knocking signal,

a retard amount changing circuit for changing the retard amount for each knocking in response to said knocking signal produced from said knocking detector circuit in accordance with the intensity thereof,

a retard amount computing circuit for computing a retard amount behind a basic ignition timing in response to a retard amount signal produced from said retard amount changing circuit, and

an ignition timing computing circuit for determining the actual ignition timing by subtracting the retard amount produced by said retard amount computing circuit from said basic ignition timing.

3. An ignition timing control system comprising:

a knocking detector for detecting an engine knocking and;

an electronic control unit for controlling the ignition timing from a detection signal produced by said knocking detector,

said control unit discriminating the intensity of knock from the detection signal,

said control unit further discriminating the interval between occurring knocks, and

said control unit still further varying the retard angle amount per one knocking in accordance with both of said discriminating results, said control unit comprising;

a knocking detector circuit for detecting the presence and absence of a knocking and the intensity thereof in response to a detection signal produced from said knocking detector,

a retard amount changing circuit for changing the retard amount for each knocking in response to a knocking signal produced from said knocking detector circuit in accordance with the intensity thereof, said retard amount changing circuit including a monostable circuit triggered by said knocking signal produced from said knocking detector circuit for generating a pulse signal having a predetermined time duration, first switch means turned on and off for said predetermined time duration in response to the pulse signal from said monostable circuit, said first switch means having a charging constant current source, a capacitor adapted to be charged from said charging constant current source when said first switch means is turned on, a comparator for comparing the charge voltage of said capacitor with a threshold level and generating a timer signal having a predetermined duration, and second switch means adapted to be turned on and off in response to the timer signal produced from said comparator, said second switch means having first and second charging constant current sources,

a retard amount computing circuit for computing a retard amount behind a basic ignition timing in response to a retard amount signal produced from said retard amount changing circuit, and

an ignition timing computing circuit for determining the actual ignition timing by subtracting the retard amount produced by said retard amount computing circuit from said basic ignition timing.

4. A system according to claim 3, wherein said retard amount computing circuit includes switch means adapted to be turned on and off in response to a pulse signal produced from said knocking detector circuit, and a capacitor adapted to be charged by selected one of said first and second charging constant current sources of said retard amount changing circuit thereby to provide a predetermined retard amount when said switch means is turned on.

5. An ignition timing control system comprising:

a knocking detector for detecting an engine knocking and;

an electronic control unit for controlling the ignition timing from a detection signal produced by said knocking detector,

said control unit discriminating the intensity of knock from the detection signal,

said control unit further discriminating the interval between occurring knocks, and

said control unit still further varying the retard angle amount per one knocking in accordance with both of said discriminating results, said control unit comprising;

a knocking detector circuit for detecting the presence and absence of a knocking and the intensity thereof in response to a detection signal produced from said knocking detector,

a retard amount changing circuit for changing the retard amount for each knocking in response to a knocking signal produced from said knocking detector circuit in accordance with the intensity thereof, said retard amount changing circuit including a monostable circuit adapted to be triggered by the knocking signal produced from said knocking detection circuit and producing a pulse signal having a predetermined duration, a counter adapted to be reset by the pulse signal produced from said monostable circuit and supplied with a basic ignition timing clock signal from said distributor, a flip-flop circuit adapted to be set by the pulse signal produced from said monostable circuit and reset by a predetermined count signal produced from said counter, and switch means adapted to be turned on and off by a timer signal having a predetermined duration produced from said flip-flop circuit, said switch means having first and second changing constant current sources,

a retard amount computing circuit for computing a retard amount behind a basic ignition timing in response to a retard amount signal produced from said retard amount changing circuit, and

an ignition timing computing circuit for determining the actual ignition timing by subtracting the retard amount produced by said retard amount computing circuit from said basic ignition timing.