US 4,393,850 AGranted

Ignition system for internal combustion engines

AssigneeNippon Soken, Inc.

InventorsMinoru Nishida, Tadashi Hattori, Akira Tanaka

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Abstract

An ignition system for an internal combustion engine includes an ignition coil system for applying a secondary generated voltage of an ignition coil and a DC high voltage to each of spark plugs and an ignition control circuit for controlling the ignition coil system. The ignition control circuit includes an ignition coil control circuit for energizing and deenergizing the ignition coil and a DC high voltage generating circuit for generating a DC high voltage. The DC high voltage generating circuit generates the DC high voltage from before the secondary generated voltage of the ignition coil causing capacitive discharge at a spark plug to a predetermined time or crank angle after the start of the discharge.

Claims9

Dependent claims

An ignition system for an internal combustion engine having a plurality of spark plugs comprising:

an ignition coil including a primary coil and a secondary coil for generating a secondary voltage including a high voltage generated by interruption of a primary coil current, said secondary voltage reaching a dielectric breakdown voltage of a gap between discharge electrodes of any one of said spark plugs to cause a capacitive discharge therebetween;
a DC high voltage generating circuit for generating a DC high voltage which is, in absolute value magnitude, lower than the dielectric breakdown voltage and higher than a voltage required to sustain discharge between the discharge electrode gap during a predetermined time interval from before occurrence of the capacitive discharge to a predetermined time or a predetermined crank angle thereafter;
said DC high voltage generating circuit including memory means for storing a plurality of predetermined time periods corresponding to a plurality of engine conditions and for generating a signal indicative of one of said time periods in response to a detected engine condition, and a circuit responsive to said output signal of said memory means to determine said predetermined time interval after the beginning of the capacitive discharge, whereby the time of interrupting said DC high voltage is determined in dependence on the detected engine condition;
an output circuit for selectively applying one of the secondary voltage and the DC high voltage to the discharge electrode gap in accordance with relative levels of both voltages;
and
an ignition coil control circuit for controlling supply and interruption of the primary coil current.

3 more elements

An ignition system for an internal combustion engine comprising:

an ignition coil having a primary winding and a secondary winding for generating a secondary voltage including a high voltage generated by interruption of a primary current, said secondary voltage being decreased after occurrence of capacitive discharge at one of a plurality of spark plugs;
said plurality of spark plugs each being supplied with said secondary voltage of said ignition coil, at each of said spark plugs capacitive discharge is caused when said ignition coil secondary voltage reaches a dielectric breakdown voltage of a gap between electrodes of the spark plug and then sustained discharge is caused;
ignition signal generating means for generating an AC signal synchronized with the rotation of the engine;
control signal generating means responsive to said AC signal synchronized with the engine rotation to generate a control pulse signal having a first transition edge indicative of a time of starting flow of a primary current in said ignition coil and a second transition edge indicative of a time of interrupting the primary current flow;
control means responsive to said control pulse signal to control the primary current flow in said ignition coil;
a monostable circuit responsive to said control pulse signal to generate a pulse signal having a duration for a predetermined time interval from the second transition edge of the control pulse signal to a predetermined time or crank angle;
an oscillator circuit for generating repetitive pulses of a predetermined repetition rate;
an AND circuit having a first input terminal for receiving the output pulse signal of said monostable circuit and a second input terminal for receiving the repetitive pulses from said oscillator circuit for delivering the repetitive pulses during said predetermined time interval;
switching means responsive to the output pulse signal of said AND circuit to perform on-off operation during said predetermined time interval;
transformer means whose primary current is controlled in response to the operation of said switching means to thereby generate a high voltage pulse in its secondary winding during said predetermined time interval;
DC high voltage generating means for rectifying and smoothing said secondary high voltage pulse from said transformer means to generate during said predetermined time interval a DC high voltage which is lower than said dielectric breakdown voltage of spark plug gap in absolute value magnitude and which is higher than a voltage required to maintain said sustained discharge in absolute value magnitude;
and
output means connected to the secondary winding of said ignition coil and said DC high voltage generating means, whereby one of said secondary voltage generated by said ignition coil and said DC high voltage is selected in accordance with the relative levels thereof and supplied to the spark plug.

10 more elements

An ignition system for an internal combustion engine comprising:

an ignition coil having a primary winding and a secondary winding for generating a secondary voltage including a high voltage generated by interruption of a primary current, said secondary voltage being decreased after occurrence of capacitive discharge at one of a plurality of spark plugs;
said plurality of spark plugs each being supplied with said secondary voltage of said ignition coil, at each of said spark plugs capacitive discharge is caused when said ignition coil secondary voltage reaches a dielectric breakdown voltage of a gap between electrodes of the spark plug and then sustained discharge is caused;
ignition signal generating means for generating an AC signal synchronized with the rotation of the engine;
control signal generating means responsive to said AC signal synchronized with the engine rotation to generate a control pulse signal having a first transition edge indicative of a time of starting flow of a primary current in said ignition coil and a second transition edge indicative of a time of interrupting the primary current flow and corresponding to the point of positive to negative transition of said AC signal synchronized with the engine rotation;
control means responsive to said control pulse signal to control the primary current flow in said ignition coil;
comparison means connected to said ignition signal generating means for comparing said AC signal synchronized with the engine rotation and a positive reference voltage so as to generate a pulse signal for a period of time during which said AC signal is greater than said reference voltage;
first trigger pulse generating means responsive to the leading edge of said output pulse signal of said comparison means to generate a first trigger pulse;
monostable circuit means responsive to said control pulse signal to generate a pulse signal for a predetermined period from the second transition edge of said control pulse signal;
second trigger pulse generating means responsive to the trailing edge of said output pulse signal of said monostable circuit means to generate a second trigger pulse;
a flip-flop circuit responsive to said first and second trigger pulses to generate a pulse signal having a duration for a time interval from the time of generation of said first trigger pulse to the time of generation of said second trigger pulse;
an oscillator for generating repetitive pulses having a predetermined repetition rate;
an AND circuit having a first input terminal for receiving said output pulse signal of said flip-flop circuit and a second input terminal for receiving said repetitive pulses from said oscillator for delivering the repetitive pulses during said time interval;
switching means responsive to the output pulse signal of said AND circuit to perform on-off operations during said time interval;
transformer means whose primary current is controlled in response to the operation of said switching means, to thereby generate a high voltage pulse in its secondary winding during said time interval;
DC high voltage generating means for rectifying and smoothing said secondary high voltage pulse from said transformer means to generate during said time interval a DC high voltage which is lower than said dielectric breakdown voltage of spark plug gap in absolute value magnitude and which is higher than a voltage required to maintain said sustained discharge in absolute value magnitude;
and
output means connected to the secondary winding of said ignition coil and said DC high voltage generating means, whereby one of said secondary voltage generated by said ignition coil and said DC high voltage is selected in accordance with the relative levels thereof and supplied to the spark plug.

14 more elements

An ignition system for an internal combustion engine comprising:

an ignition coil having a primary winding and a secondary winding for generating a secondary voltage including a high voltage generated by interruption of a primary current, said secondary voltage being decreased after occurrence of capacitive discharge at one of a plurality of spark plugs;
said spark plugs each being supplied with said secondary voltage of said ignition coil, at each of said spark plugs capacitive discharge is caused when said ignition coil secondary voltage reaches a dielectric breakdown voltage of a gap between electrodes of the spark plug and then sustained discharge is caused;
ignition signal generating means for generating an AC signal synchronized with the rotation of the engine;
control signal generating means responsive to said AC signal synchronized with the engine rotation to generate a control pulse signal having a first transition edge indicative of a time of starting flow of a primary current in said ignition coil and a second transition edge indicative of a time of interrupting the primary current flow;
control means responsive to said control pulse signal to control the primary current flow in said ignition coil;
a first monostable circuit responsive to said control pulse signal to generate a pulse signal having a duration for a predetermined time interval from the second transition edge of the control pulse signal to a predetermined time or crank angle;
a second monostable circuit connected to said first monostable circuit to generate a pulse signal having a duration from the trailing edge of the output pulse signal of said first monostable circuit to a determined time;
switching means responsive to the output pulse signal of said second monostable circuit so as to be turned on;
DC high voltage generating means for generating a DC high voltage which is lower than said dielectric breakdown voltage of spark plug gap in absolute value magnitude and which is higher than a voltage required to maintain said sustained discharge in absolute value magnitude;
DC high voltage output means connected to an output of said DC high voltage generating means and said switching means, whereby said DC high voltage is delivered when said switching means is off and a DC voltage lower than said voltage required to maintain said sustained discharge is generated when said switching means is on;
and
output means connected to the secondary winding of said ignition coil and said DC high voltage output means, whereby one of said secondary voltage generated by said ignition coil and said DC output voltage of said DC high voltage output means is selected in accordance with the relative levels thereof and supplied to the spark plug.

9 more elements

An ignition system for an internal combustion engine comprising:

an ignition coil having a primary winding and a secondary winding for generating a secondary voltage including a high voltage generated by interruption of a primary current, said secondary voltage being decreased after occurrence of a capacitive discharge at one of a plurality of spark plugs;
said plurality of spark plugs each being supplied with said secondary voltage of said ignition coil, at each of said spark plugs capacitive discharge is caused when said secondary voltage reaches a dielectric breakdown voltage of a gap between electrodes of the spark plug and then sustained discharge is caused;
ignition signal generating means for generating an AC signal synchronized with the rotation of the engine;
control signal generating means responsive to said AC signal synchronized with the engine rotation to generate a control pulse signal having a first transition edge indicative of a time of starting flow of primary current in said ignition coil and a second transition edge indicative of a time of interrupting the primary current flow and corresponding to the point of positive to negative transition of said AC signal synchronized with the engine rotation;
control means responsive to said control pulse signal to control the primary current flow in said ignition coil;
comparison means connected to said ignition signal generating means for comparing said AC signal synchronized with the engine rotation and a positive reference voltage to generate a pulse signal for a period of time during which said AC signal is greater than said reference voltage;
trigger pulse generating means responsive to the leading edge of said output pulse signal of said comparison means to generate a first trigger pulse;
an oscillator for generating repetitive pulses having a predetermined repetition rate;
a counter responsive to the second transition edge of said control pulse signal to start counting said repetitive pulses of said oscillator;
memory means for storing a plurality of predetermined time periods or crank angles each corresponding to one of a plurality of engine conditions and for producing in accordance with a detected engine condition, a signal indicative of the corresponding one of said predetermined time periods or crank angles;
a comparison circuit connected to said counter and said memory means to generate an output pulse as a second trigger pulse when the output of said counter coincides with the output of said memory means;
a flip-flop circuit responsive to said first and second trigger pulses to generate a pulse signal having a duration for a time interval from the time of generation of said first trigger pulse to the time of generation of said second trigger pulse;
an oscillator circuit for generating repetitive pulses of a predetermined repetition rate;
an AND circuit having a first input terminal for receiving said output pulse signal of said flip-flop circuit and a second input terminal for receiving said repetitive pulses from said oscillator circuit to deliver said repetitive pulses signal during said time interval;
switching means responsive to the output pulse signal of said AND circuit to perform on-off operations during said time interval;
transformer means whose primary current is controlled in response to the operation of said switching means, to thereby generate a high voltage pulse in its secondary winding during said time interval;
DC high voltage generating means for rectifying and smoothing said secondary high voltage pulse from said transformer means to generate during said time interval a DC high voltage which is lower than said dielectric breakdown voltage of spark plug gap in absolute value magnitude and which is higher than a voltage required to maintain said sustained discharge in absolute value magnitude;
and
output means connected to the secondary winding of said ignition coil and said DC high voltage generating means, whereby one of said secondary voltage generated by said ignition coil and said DC high voltage is selected in accordance with the relative levels thereof and supplied to the spark plug.

16 more elements

Dependencies are inferred from the claim text.