Controller for internal combustion engine

• US 4,450,811 A
• Filed: 09/30/1982
• Issued: 05/29/1984
• Est. Priority Date: 10/08/1981
• Status: Expired due to Term

• Current Assignee: NGK Spark PLUG Company Limited
• Original Assignee: NGK Spark PLUG Company Limited
• Inventors: Ichikawa, Sadao
• Primary Examiner(s): Cox, Ronald B.
• Application Number:
  US06/430,225
• Time in Patent Office: 607 Days
• Field of Search: 123/425, 123/435, 73/35
• US Class Current: 123/406.37
• CPC Class Codes: G01L 23/222 using piezoelectric devices
• CPC Class Codes: G01L 23/225 circuit arrangements therefor

Abstract

A controller for controlling the combustion timing of an internal combustion engine and a method for controlling the ignition timing of an internal combustion engine in which variations in combustion timing as detected from the pressure in the combustion chamber of the engine and the intensity of knocking are simultaneously detected and the ignition timing corrected to provide optimum combustion efficiency at all times. From the sensed pressure in the combustion chamber, the crank angle at which the maximum pressure occurs is determined. If the crank angle thus determined exceeds a first reference value, a first ignition time correcting signal is generated. If the knocking intensity exceeds a second reference value, a second ignition timing correcting signal is generated. The output signal utilized to correct the ignition timing is produced by selecting one of the two ignition timing correcting signals thus generated, wherein the second ignition timing correcting signal has priority over the first ignition timing correcting signal.

Claims

1. A method for controlling the combustion in an internal combustion engine, comprising the steps of:

sensing a crank angle of said engine corresponding to a time of maximum pressure in a combustion chamber of said engine;

sensing a reference crank angle;

providing a first ignition timing correcting signal when the sensed crank angle is delayed beyond said reference crank angle;

sensing a knocking intensity;

producing a second signal for correcting said ignition timing when said sensed knocking intensity exceeds a predetermined reference level; and

effecting correction of said ignition timing in response to one of said first and second ignition timing correcting signal with said second ignition timing correcting signal having priority over said first ignition timing correcting signal, and wherein said step of correcting said ignition timing in accordance with one of said first and second ignition timing correcting signals comprises inhibiting said first ignition timing correcting signal for a predetermined time period in response to said second ignition timing correcting signal.

2. A controller for controlling the combustion in an internal combustion engine comprising:

a pressure sensor for sensing a gas pressure within a combustion chamber of said engine;

means for detecting a moment of maximum pressure from an output of said pressure sensor;

a crank angle sensor;

a maximum-pressure crank angle detecting circuit for determining in response to outputs from said pressure detecting means and said crank angle sensing means a crank angle at which a maximum pressure in said combustion chamber occurs;

first comparing means for comparing an output of said maximum-pressure crank angle detecting circuit with a first predetermined reference value for producing a first ignition timing correcting signal when the crank angle at which said maximum pressure occurs exceeds said first predetermined reference value;

knocking intensity detecting means operating in response to an output of said pressure detector;

second comparing means for comparing a knocking intensity signal produced by said knocking intensity detecting means with a second predetermined reference value for producing a second ignition timing correcting signal when the detected knocking intensity exceeds said second predetermined reference value; and

selecting circuit means for delivering as an output ignition timing correcting signal one of said first and second ignition timing correcting signals, wherein said second ignition timing correcting signal has priority over said first ignition timing correcting signal, and wherein said selecting means comprises means for inhibiting from said output ignition correcting signal said first ignition timing correcting signal for a predetermined time after said second ignition timing correcting signal is received.

3. A controller for controlling the combustion in an internal combustion engine comprising:

a pressure sensor for sensing a gas pressure within a combustion chamber of said engine;

means for detecting a moment of maximum pressure from an output of said pressure sensor;

a crank angle sensor;

a maximum-pressure crank angle detecting circuit for determining in response to outputs from said pressure detecting means and said crank angle sensing means a crank angle at which a maximum pressure in said combustion chamber occurs;

first comparing means for comparing an output of said maximum-pressure crank angle detecing circuit with a first predetermined reference value for producing a first ignition timing correcting signal when the crank angle at which said maximum pressure occurs exceeds said first predetermined reference value;

knocking intensity detecting means operating in response to an output of said pressure detector;

second comparing means for comparing a knocking intensity signal produced by said knocking intensity detecting means with a second predetermined reference value for producing a second ignition timing correcting signal when the detected knocking intensity exceeds said second predetermined reference value; and

selecting circuit means for delivering as an output ignition timing correcting signal one of said first and second ignition timing correcting signals, wherein said second ignition timing correcting signal has priority over said first ignition timing correcting signal, and wherein said crank angle sensor comprises a disc coupled to be rotated by the crank of said engine, said disc having a first projection at a position indicative of a top-dead-center crank angle, and a plurality of second projections spaced at equal intervals on said disc; and

first and second stationarily mounted projection sensors for sensing said first projection and said projections, respectively, for producing a top-dead-center position signal and an incremental angle signal, respectively, said first comparing means comprising an RS flip-flop, an AND gate, a counter, and an analog-to-digital converter, said flip-flop having an R input coupled to receive said maximum-pressure signal outputted by said pressure detecting means, an S input coupled to receive said top-dead-center position signal, and a Q output coupled to a first input of said AND gate, said AND gate having a second input coupled to receive said incremental angle signal and an output coupled to a clock input of said counter, said counter having a reset input coupled to said R input of said flip-flop and outputs coupled to digital inputs of said digital-to-analog converter, an output of said digital-to-analog converter forming said first ignition timing correcting signal.