Ignition system improvements for internal combustion engines

An ignition system for a spark ignition internal combustion engine comprising:

• a pulse transformer having a primary winding and a secondary winding connected to a spark plug;
• driver means for supplying a voltage signal to said pulse transformer primary winding thereby inducing a high voltage signal and said secondary winding applied to said spark plug;
• controller means for providing control signals to said driver means, thereby causing said driver means to generate a voltage applied to said secondary winding, and
• discharge detection means for sensing the occurrence of electrical discharge across said spark plug and applying a discharge signal to said controller means for controlling the operation of said controller means;
• wherein said controller means minimizes the duty cycle of said transformer by terminating the control signal to said driver means upon the detection of discharge by said discharge detector means.

An ignition system for a spark ignition internal combustion engine which detects the existence of auto-ignition characterized by pressure and temperature fluctuations within the engine combustion chamber occurring after piston top dead center which departs from normal combustion, comprising:

• timing means for sensing the position of the piston and for providing a timing signal,
• an ignition spark plug having electrodes presenting an air gap within the combustion chamber,
• electrical energy source means for applying voltage to said spark gap air gap,
• controller means for receiving said timing signal and controlling said energy source means for applying a hover voltage of a predetermined maximum level across said spark plug gap during a period of the cylinder operating cycle after piston top dead center, said hover voltage applied at a level at which discharge across the spark plug occurs in the even that said combustion chamber is experiencing auto-ignition but does not occur if the conditions within the cylinder are of normal combustion, and
• discharge detection means for sensing the occurrence of electrical discharge across said spark plug gap caused by said hover voltage, thus providing an indication of the existence of auto-ignition.

An ignition system for a spark ignition internal combustion engine which detects the existence of auto-ignition characterized by pressure and temperature fluctuations within the engine combustion chamber occurring after piston top dead center which departs from normal combustion comprising:

• timing means for sensing the position of the piston and for providing a timing signal,
• an ignition spark plug having electrodes presenting and air gap within the combustion chamber,
• a pulse transformer mounted directly to said spark plug having a primary winding and a secondary winding, said secondary winding electrically connected to said spark plug electrodes,
• a driver circuit for transmitting a pulse of voltage to said pulse transformer primary winding in response to control signals thereby producing a high voltage signal at said spark plug electrodes,
• a spark discharge detector including a ground return conductor electrically connected to one of said spark plug electrodes connected to ground, said conductor also connected to ground and further including a current detector for sensing current flow in said conductor, wherein said spark discharge detector senses the short duration high level current flow which occurs at the onset of arcing across said spark plug gap, and
• controller means for receiving said timing signals and providing said control signals to said driver circuit, said controller means applying a hover voltage of a predetermined maximum level across said spark plug gap during a period of the cylinder operating cycle after piston top dead center, said hover voltage maximum level being set such that which discharge across the spark plug occurs in the event that said combustion chamber is experiencing auto-ignition, but does not occur if the conditions within the cylinder are of normal combustion, and said controller means modifying spark timing in response to said spark discharge detector.

An ignition system for a spark ignition internal combustion engine which detects the existence of auto-ignition characterized by pressure and temperature fluctuations within the engine combustion chamber occurring after piston top dead center which departs from normal combustion comprising:

• timing means for sensing the position of the piston and for providing a timing signal,
• an ignition spark plug having electrodes presenting an air gap within the combustion chamber,
• a pulse transformer mounted directly to said spark plug having a primary winding and a secondary winding, said secondary winding electrically connected to said spark plug electrodes,
• a driver circuit for transmitting a pulse of voltage to said pulse transformer primary winding in response to control signals thereby producing a high voltage signal at said spark plug electrodes,
• a spark discharge detector including a ground return conductor electrically connected to one of said spark plug electrodes connected to ground, said conductor also connected to ground and further including a current detector for sensing current flow in said conductor, wherein said spark discharge detector senses the short duration high level current flow which occurs at the onset of arcing across said spark plug gap, and
• controller means for receiving said timing signals and providing said control signals to said driver circuit, said controller means providing an interrogation control signal at a period of the piston operating cycle where auto-ignition does not normally occur, said interrogation control signal causing an interrogation pulse voltage at said spark plug gap to increase over time until said interrogation voltage reaches the breakdown voltage which causes discharge across said gap, said breakdown voltage being affected by pressure and temperature conditions that said spark plug electrodes are exposed to, and for measuring the phase difference between the leading edge of said interrogation control signal and said breakdown current which said phase difference is an indication of said conditions, said controller means further applying a hover voltage of a predetermined maximum level across said spark plug gap during a period of the cylinder operating cycle after piston top dead center, said hover voltage applied a a level at which discharge across the spark plug occurs in the event that said combustion chamber is experiencing auto-ignition but does not occur if the conditions within the cylinder are of normal combustion, and said controller means further for adjusting the level of said hover voltage in response to s id phase difference to thereby adjust said hover voltage in response to said interrogation pulse breakdown voltage.

An ignition system for a spark plug ignited internal combustion engine for improved lean air/fuel mixture burn limits comprising:

• a pulse transformer having a primary winding and a secondary winding connected to the spark plug;
• driver circuit means for supplying a voltage pulse to said pulse transformer primary winding thereby inducing a high voltage in said secondary winding;
• controller means for generating control signals causing said driver circuit means to cause said pulse transformer to output a series of pulses from said secondary winding thereby causing a series of spark discharges starting less than 100 microseconds apart, whereby the multiple firing of the spark plug enables leaner air/fuel mixtures to be combusted as compared with a single spark discharge;
• and
• discharge detection means for sensing the occurrence of electrical discharge across the spark plug electrodes and wherein said controller means terminates said control signal upon the detection of said discharge.

An ignition system for a spark plug ignited internal combustion engine for improved lean air/fuel mixture burn limits comprising;

• a pulse transformer mounted to the spark plug and having a primary winding and a secondary winding connected to the spark plug,
• driver circuit means for supplying a voltage pulse to said pulse transformer primary winding thereby inducing a higher voltage in said secondary winding,
• controller means for generating control signals causing said driver circuit means to cause said pulse transformer to output a series of pulses from said secondary windings thereby causing a series of spark discharges across electrodes of said spark plug, said discharges starting less than 100 microseconds apart, whereby the multiple firing of the spark plug enables leaner air/fuel mixtures to be combusted as compared with a single spark plug discharge, and
• discharge detection means for sensing the occurrence of electrical discharge across the spark plug electrodes and providing a signal to said controller means for terminating said control signal upon the detection of said discharge.

An ignition system for a spark ignition internal combustion engine comprising

• a pulse transformer having a primary winding and a secondary winding connected to said plug,
• driver circuit means for supplying a voltage signal to said pulse transformer primary winding thereby inducing a high voltage pulse in said secondary winding applied to said spark plug gap,
• controller means for providing control signals to said driver circuit means,
• discharge detection means for sensing the occurrence of electrical discharge across said spark plug gap caused by said pulse transformer secondary voltage, and
• said controller means receiving a discharge signal from said discharge detection means and causing said control signal to be curtailed thereby minimizing the duration of said secondary winding pulse.

An ignition system for a spark ignition internal combustion engine which senses abnormal conditions within the engine combustion chamber comprising;

• a pulse transformer having a primary winding and a secondary winding connected to said plug,
• driver circuit means for supplying a voltage signal to said pulse transformer primary winding thereby inucing a high voltage pulse through said secondary winding,
• controller means for providing a control signal to said driver circuit means whereby at the onset of said control signal, the voltage at a spark plug rises with respect to time until a breakdown voltage is reached causing electrical discharge across the spark plug, and wherein normal operation of said engine will result in said breakdown voltage having a magnitude within a voltage range, and wherein abnormal conditions within said combustion chamber will result in a breakdown voltage which is outside said range,
• discharge detection means for sensing the short duration, high level current flow occurring at the initiation of discharge across the spark plug, and
• wherein said controller means measures the breakdown voltage thereby providing a means for detecting said abnormal con itions.