Combustion condition diagnosis utilizing multiple sampling of ionic current

An apparatus for combustion condition diagnosis, comprising:

• voltage supplying means for applying a predetermined voltage to an ignition plug immediately after sparking of said ignition plug;
• measuring means for measuring a voltage at a secondary side of an ignition coil, which is connected to said ignition plug, during a plurality of successive time periods during one operation cycle, including a time period in which an internal pressure of a combustion chamber in which the spark plug is disposed becomes maximum under a normal combustion condition and a time period in which charging of a voltage to a primary side of the ignition coil is initiated;
• feature extracting means for extracting features of the voltage measured in each of said time periods;
• memory means for storing a list of combustion conditions corresponding to said features extracted in each of said time periods;
• and
• combustion condition judging means for diagnosing a combustion condition in said cylinder based on said features extracted in each of said time periods and said list of combustion conditions stored in said memory means.

An apparatus for combustion condition diagnosis, comprising:

• combustion condition judging means for diagnosing various kinds of combustion conditions of an engine on the basis of a plurality of values of current flowing through a spark plug as detected during respective time periods in one operation cycle of the spark plug;
• frequency memory means for storing frequencies of occurrence of the various kinds of combustion conditions diagnosed by said combustion condition judging means, respectively;
• and
• display means for displaying results of diagnosis relating to only a combustion condition which has a frequency of occurrence which exceeds a predetermined value or a value defined by a predetermined function assigned respectively to each kind of combustion condition among frequencies of occurrence of said various kinds of combustion conditions.

A method of combustion condition diagnosis comprising the steps of;

• applying a predetermined voltage to an ignition plug installed in a combustion chamber at least immediately after sparking of said ignition plug;
• measuring a voltage or electric current at said ignition plug to which said predetermined voltage is applied during a plurality of successive time periods during one operation cycle, including a time period in which an internal pressure in said combustion chamber becomes maximum under a normal combustion condition;
• extracting features of said voltage or electric current measured in each time period;
• and
• diagnosing combustion condition of an engine based on the features extracted during each time period.

A method of combustion condition diagnosis comprising the steps of;

• diagnosing various kinds of combustion conditions of an engine on the basis of a plurality of values of current flowing through a spark plug as detected during respective time periods in one operation cycle of the spark plug;
• storing frequencies of occurrence of various kinds of diagnosed combustion conditions for each kind of combustion condition, respectively;
• and
• displaying results of the diagnosis relating to only a combustion condition which has a frequency of occurrence which exceeds a predetermined value or a value defined by a predetermined function assigned respectively to each kind of combustion condition among frequencies of occurrence of said various kinds of combustion conditions.

A combustion control apparatus, comprising:

• voltage supplying means for applying a predetermined voltage to an ignition plug disposed in a combustion chamber;
• measuring means, to be connected to a secondary side of an ignition coil which is connected to said ignition plug, for measuring an electric current flowing through said ignition plug during a plurality of successive time periods during one operation cycle, including a time period in which an internal pressure of said combustion chamber becomes maximum under a normal combustion condition;
• feature extracting means for extracting features of the electric current measured in each of said time periods;
• memory means for storing a list of combustion conditions corresponding to said features extracted in each of said time periods;
• combustion condition judging means for diagnosing a combustion condition in said combustion chamber based on said features extracted in each of said time periods and said list of combustion conditions stored in said memory means;
• and
• control means for altering various controlled variables of an engine corresponding to various combustion conditions diagnosed by said combustion condition judging means.

A combustion control apparatus, comprising:

• voltage supplying means for applying a predetermined voltage to an ignition plug immediately after sparking of said ignition plug;
• measuring means for measuring a voltage at a secondary side of an ignition coil, which is connected to said ignition plug, during a plurality of successive time periods during one operation cycle, including a time period in which an internal pressure of a combustion chamber in which the spark plug is disposed becomes maximum under a normal combustion condition and a time period in which charging of a voltage to a primary side of the ignition coil is initiated;
• feature extracting means for extracting features of the voltage measured in each of said time periods;
• memory means for storing a list of combustion conditions corresponding to said features extracted in each of said time periods;
• combustion condition judging means for diagnosing a combustion condition in said cylinder based on said features extracted in each of said time periods and said list of combustion conditions stored in said memory means;
• and
• control means for altering various controlled variables of an engine corresponding to various combustion conditions diagnosed by said combustion condition judging means.

An apparatus for combustion condition diagnosis, comprising:

• voltage supplying means for applying a predetermined voltage to an ignition plug disposed in a combustion chamber immediately after the ignition plug fires;
• measuring means for measuring an electric current flowing through said ignition plug during a plurality of successive time periods during one operation cycle, including a time period in which an internal pressure of said combustion chamber becomes maximum under a normal combustion condition;
• and
• combustion condition judging means for diagnosing a combustion condition in said combustion chamber based on the values of electric current measured in said plurality of successive time periods.