Electrical control method and apparatus for combustion engines

A method for controlling a combustion engine having an output shaft driven by mechanical energy converted from heat energy caused by the combustion of an air-fuel mixture, said engine including first and second control means for controlling the combustion of said air-fuel mixture in accordance with changes in a condition of said engine, said method comprising the steps of:

• a. generating an electrical signal in the form of a binary number, the signal indicating a condition of said engine as of a selected instant in time during operation of said engine;
• b. generating a synchronized pulse as part of a pulse train synchronized with and in response to the rotational speed of said output shaft;
• c. generating at least one clock pulse in a predetermined time interval;
• d. sequentially calculating first and second values corresponding to respective settings of said first and second control means by a computer programmed to calculate said first and second values from a first function describing a desired relationship between the condition of said engine and the setting of said first control means and from a second function describing another desired relationship between the condition of said engine and the setting of said second control means, the calculations of said first and second values being respectively performed using said binary number electrical signal in accordance with said synchronized pulse and said clock pulse such that the calculation of said first value is conducted first by said computer in response to receipt of said synchronized pulse even during the calculation of said second value, and the rest of the calculation of said second value is subsequently conducted after completion of the calculation of said first value;
• e. converting said first and second calculated values into the settings of said first and second control means;
• and
• f. continuously repeating the above sequence of steps for controlling the combustion of the air-fuel mixture in response to any changes in said binary number electrical signal.

In an electrical control apparatus for a combustion engine having an output shaft driven by mechanical energy converted from heat energy caused by the combustion of an air-fuel mixture, said engine including first control means for controlling either the amount of air-fuel mixture metered into said engine and/or the spark-ignition timing of said engine and second control means for controlling the amount of exhaust gases recirculated from an exhaust pipe into said engine, said control apparatus including:

• a first electrical circuit for generating an electrical signal in the form of a binary number, the signal indicating a condition of said engine as of a selected instant in time during the operation of said engine;
• a digital computer for sequentially calculating first and second values corresponding to respective settings of said first and second control means by using said binary number electrical signal, said computer being programmed to calculate said first and second values from a first function describing a desired relationship between the condition of said engine and the setting of said first control means and from a second function describing another desired relationship between the condition of said engine and the setting of said second control means;
• and
• a second electrical circuit coupled between said digital computer and said first and second control means for converting said first and second calculated values into the settings of said first and second control means;
• the improvement comprising:
• a detector for generating output pulses at a frequency proportional to the rotational speed of said output shaft to initiate the calculation of said first value in said computer;
• a clock circuit for generating clock pulses at a predetermined frequency to initiate the calculation of said second value in said computer, the frequency of said clock pulses being substantially lower than that of said output pulses from said detector during the idling of said engine;
• and
• an interrupt controller for issuing an interrupt request signal therefrom upon receiving one of said output pulses from said detector during the calculation of said second value to prohibit the calculation of said second value in said computer and to simultaneously initiate the calculation of said first value in said computer, the remainder of the prohibited calculation being executed in said computer after completion of the calculation of said first value, said interrupt controller issuing an interrupt prohibit signal therefrom during the calculation of said first value to continue the calculation of said first value in said computer.

A method for controlling a combustion engine having an output shaft driven by mechanical energy converted from heat energy caused by the combustion of an air-fuel mixture, said engine including first control means for controlling the amount of air-fuel mixture metered into said engine and/or the spark-ignition timing of said engine and second control means for controlling the amount of exhaust gases recirculated from an exhaust pipe into said engine, said method comprising the steps of:

• a. generating an electrical signal in the form of a binary number, said signal indicating a condition of said engine as of a selected instant in time during operation of said engine;
• b. generating output pulses at a frequency proportional to the rotational speed of said output shaft to initiate the calculation of a first value;
• c. generating clock pulses at a predetermined frequency, the frequency of said clock pulses being lower than that of said output pulses;
• d. sequentially calculating first and second values corresponding to respective settings of said first and second control means by a computer programmed to calculate said first and second values from a first function describing a desired relationship between the condition of said engine and the setting of said first control means and from a second function describing another desired relationship between the condition of said engine and the setting of said second control means, each calculation of the first and second values being executed by using said binary number electrical signal in response to said output pulses and said clock pulses, respectively;
• e. issuing an interrupt request signal in response to one of said output pulses during the calculation of said second value in said computer to prohibit the calculation of said second value in said computer and simultaneously initiate the calculation of said first value in said computer, the remainder of the prohibited calculation being executed in said computer after completion of the calculation of said first value;
• f. issuing an interrupt prohibit signal during the calculation of said first value to continue the calculation of said first value in said computer;
• g. converting said first and second calculated values into the settings of said first and second control means;
• and
• h. continuously repeating the above sequence of steps for controlling the combustion of the air-fuel mixture in response to any changes in said binary number electrical signal.