Abstract: The present invention provides a spark plug coil and pressure sensor assembly for providing a spark to a cylinder of an internal combustion engine. The assembly comprises a spark plug configured for mounting in a cylinder and a pressure sensor associated with the spark plug configured to detect a pressure in the cylinder and generate a pressure signal in response thereto. The assembly includes a first electrically conductive ring connector configured to receive the pressure signal and a housing having a main axis and having at least one electrically conductive leaf spring member. The leaf spring member is configured to resiliently engage the first electrically conductive ring connector over a first predetermined circumferential angle relative to the main axis of the coil housing.

Abstract: An ignition coil durability testing apparatus and method utilizing an electronic spark timing circuit, a plurality of SCRs, a plurality of LEDs, and a voltage detection circuit. The electronic spark timing circuit activates an ignition switching transistor which applies a time varying voltage to a primary winding of an ignition coil. The plurality of SCRs are connected in series. A sustaining voltage device in the form of a spark gap or zener box is connected in series with the plurality of SCRs. The secondary winding of the ignition coil is connected to one end of the spark gap or an input of the zener box and to one input of a comparator through a voltage divider and a voltage reference is also connected to the other input of the comparator. When the output voltage of the secondary winding exceeds a preset breakdown voltage, the comparator turns on the plurality of LEDs which activate the plurality of SCRs.

Abstract: A thick film resistor strain gauge is applied to a stainless steel shell portion of a spark plug. There are two preferable ways of applying a thick film resistor to the metal shell. In a first embodiment, the thick film resistor may be directly printed on to the shell portion with special screen printing equipment. In a second embodiment, the thick film resistor is printed and applied as a decal to the shell portion. The thick film resistors may be included in a quarter, a half, or a full wheatstone bridge strain gauge circuit. One of two embodiments of an automatic drift compensating circuit is used to determine the change in resistance experienced by the thick film resistors affixed to the spark plug. Either one of the automatic drift compensation circuits output a voltage signal which is proportional to the pressure changes occurring inside the engine cylinder into which the spark plug is threaded.

Abstract: An ignition coil, spark plug, and pressure sensor for an internal combustion engine are, in a preferred embodiment, integrated into a single assembly and mounted directly on a plug hole of an internal combustion engine. A hard spark plug shell serves as a pressure member and on which a strain gage is affixed. Changes in the pressure in the combustion chamber deform the shell, causing a corresponding change in the resistance of the strain gage. A bridge circuit or the like is used to measure the resistance change thereby providing a direct indication of cylinder pressure.

Abstract: A thick film resistor strain gauge is applied to a stainless steel shell portion of a spark plug. There are two preferable ways of applying a thick film resistor to the metal shell. In a first embodiment, the thick film resistor may be directly printed on to the shell portion with special screen printing equipment. In a second embodiment, the thick film resistor is printed and applied as a decal to the shell portion. The thick film resistors may be included in a quarter, a half, or a full wheatstone bridge strain gauge circuit. One of two embodiments of an automatic drift compensating circuit is used to determine the change in resistance experienced by the thick film resistors affixed to the spark plug. Either one of the automatic drift compensation circuits output a voltage signal which is proportional to the pressure changes occurring inside the engine cylinder into which the spark plug is threaded.

Abstract: An ignition coil, spark plug, and pressure sense assembly for an internal combustion engine are, in a preferred embodiment, integrated into a single assembly and mounted directly on a plug hole of an internal combustion engine. A pressure sense assembly is welded to a spark plug shell which serves as a pressure member. The pressure sense assembly includes a base plate onto which first and second pairs of strain gauges are printed using a thick film ink process (piezoresistive) in a full bridge arrangement. The geometry of the base plate and the fashion in which it is welded to the shell allow one pair of the gauges to function as strain sensing elements while the other pair can function for temperature compensation. Changes in the pressure in the combustion chamber deform the shell, causing a corresponding change in the bridge producing the pressure signal.

Abstract: An impulse noise suppression circuit for an integrator-based ion current signal processing system includes a one-shot circuit activated by a trigger signal that is produced when a noise transient in a bandpass filtered ion current signal exceeds a predetermined threshold. The output pulse of the one-shot circuit is selected to have a pulse width configured to mask a substantial portion of the noise transient without masking the remaining filtered ion current signal during the remainder of a knock window in which knock is detected.

Abstract: An ignition coil durability testing apparatus and method utilizing an electronic spark timing circuit, a plurality of SCRs, a plurality of LEDs, and a voltage detection circuit. The electronic spark timing circuit activates an ignition switching transistor which applies a time varying voltage to a primary winding of an ignition coil. The plurality of SCRs are connected in series. A sustaining voltage device in the form of a spark gap or zener box is connected in series with the plurality of SCRs. The secondary winding of the ignition coil is connected to one end of the spark gap or an input of the zener box and to one input of a comparator through a voltage divider and a voltage reference is also connected to the other input of the comparator. When the output voltage of the secondary winding exceeds a preset breakdown voltage, the comparator turns on the plurality of LEDs which activate the plurality of SCRs.

Abstract: A thick film resistor strain gauge is applied to a stainless steel shell portion of a spark plug. There are two preferable ways of applying a thick film resistor to the metal shell. In a first embodiment, the thick film resistor may be directly printed on to the shell portion with special screen printing equipment. In a second embodiment, the thick film resistor is printed and applied as a decal to the shell portion. The thick film resistors may be included in a quarter, a half, or a full wheatstone bridge strain gauge circuit. One of two embodiments of an automatic drift compensating circuit is used to determine the change in resistance experienced by the thick film resistors affixed to the spark plug. Either one of the automatic drift compensation circuits output a voltage signal which is proportional to the pressure changes occurring inside the engine cylinder into which the spark plug is threaded.

Abstract: A drive circuit for an ignition system includes an ignition coil and spark plug associated with each cylinder of an internal combustion engine. Each ignition coil has a primary winding with the first end connectable to a power source and a second end opposite the first end connected to a silicon-control rectifier (SCR). Each coil also has a secondary winding connectable to a respective spark plug. The SCR may be integrated with the coil. A main driver device is connected between the other end of the SCR and ground. The driver device is configured to conduct a primary current in response to a drive signal. The SCRs are controlled into conduction by a respective gating signal. A control circuit is configured to generate the gating signals and the drive signal in response to one or more ignition control signals. An SCR for each coil is used to select which coil is allowed to carry current when the main driver is turned on.

Abstract: An ignition coil, spark plug, and pressure sensor for an internal combustion engine are, in a preferred embodiment, integrated into a single assembly and mounted directly on a plug hole of an internal combustion engine. A hard spark plug shell serves as a pressure member and on which a strain gage is affixed. Changes in the pressure in the combustion chamber deform the shell, causing a corresponding change in the resistance of the strain gage. A bridge circuit or the like is used to measure the resistance change thereby providing a direct indication of cylinder pressure.

Abstract: An ignition apparatus including a primary and a secondary winding for producing a spark voltage, an ion current detection circuit for producing an ion current signal, a slope detector and a knock detector. The slope detector determines when the ion current signal exhibits a slope indicative of a time period when knock is likely to occur, and de-asserts a knock reset signal. The knock reset signal holds the knock detector in reset, thus disallowing or masking the processing of signals by the knock detector that may be mistaken for knock.

Abstract: An impulse noise suppression circuit for an integrator-based ion current signal processing system includes a one-shot circuit activated by a trigger signal that is produced when a noise transient in a bandpass filtered ion current signal exceeds a predetermined threshold. The output pulse of the one-shot circuit is selected to have a pulse width configured to mask a substantial portion of the noise transient without masking the remaining filtered ion current signal during the remainder of a knock window in which knock is detected.

Abstract: An apparatus for detecting a combustion condition, such as knock or misfire, includes an incremental integrator in proximity with an ignition coil and provides a stream of digital pulses to a remote control unit, such as an engine control unit. The incremental integrator includes an integration device, such as a capacitor, a threshold comparator, and a pulse generator. A charging current proportional to an ion current charges the capacitor to a preset level wherein the threshold comparator changes state, causing the pulse generator to generate a pulse. The pulse is provided to the control unit, which may include a counter for counting the stream of pulses. The generated pulse also is fed back to reset the integration device, for example discharge of the capacitor. The process is repeated during a condition window, such as a knock window or a combustion window. The count held in the counter of the control unit is indicative of the level of combustion or knock, as applicable.

Abstract: A thick film resistor strain gauge is applied to a stainless steel shell portion of a spark plug. There are two preferable ways of applying a thick film resistor to the metal shell. In a first embodiment, the thick film resistor may be directly printed on to the shell portion with special screen printing equipment. In a second embodiment, the thick film resistor is printed and applied as a decal to the shell portion. The thick film resistors may be included in a quarter, a half, or a full wheatstone bridge strain gauge circuit. One of two embodiments of an automatic drift compensating circuit is used to determine the change in resistance experienced by the thick film resistors affixed to the spark plug. Either one of the automatic drift compensation circuits output a voltage signal which is proportional to the pressure changes occurring inside the engine cylinder into which the spark plug is threaded.

Abstract: An ignition coil, spark plug, and pressure sensor for an internal combustion engine are, in a preferred embodiment, integrated into a single assembly and mounted directly on a plug hole of an internal combustion engine. A hard spark plug shell serves as a pressure member and on which a strain gage is affixed. Changes in the pressure in the combustion chamber deform the shell, causing a corresponding change in the resistance of the strain gage. A bridge circuit or the like is used to measure the resistance change thereby providing a direct indication of cylinder pressure.

Abstract: An ignition coil, spark plug, and pressure sensor for an internal combustion engine are, in a preferred embodiment, integrated into a single assembly and mounted directly on a plug hole of an internal combustion engine. A hard spark plug shell serves as a pressure member and on which a strain gage is affixed. Changes in the pressure in the combustion chamber deform the shell, causing a corresponding change in the resistance of the strain gage. A bridge circuit or the like is used to measure the resistance change thereby providing a direct indication of cylinder pressure.

Abstract: A compression detection apparatus for determining which one of a pair of phase-opposed cylinders is under compression has a capacitive probe coupled to both ends of the secondary winding of an ignition coil servicing both spark plugs of the pair of cylinders. Phase and magnitude of the voltage signal appearing on the capacitive probe line are processed by a single comparator for determining which on of the pair of cylinders is under compression.

Abstract: Ignition drive circuitry for generating sequential first and second arcs across electrodes of spark plugs in internal combustion engine cylinders for contributing supplemental combustion energy and for enabling simple, robust misfire detection with a first arc generated through rapid discharge of a storage element and the second arc generated through interruption of said discharge through a transformer primary ignition coil.

Abstract: A self-diagnosing ignition drive circuit for applying a first ignition drive signal to a spark plug in an internal combustion engine cylinder for generating an arc across the electrodes thereof to ignite an air/fuel mixture in the cylinder and, following a delay period, applying a second ignition drive signal to the spark plug for generating a second arc across the electrodes to contribute combustion energy and to provide for measurement of the frequency content of energy trapped in an ignition coil during combustion. If the frequency content includes a predetermined frequency, improper ignition in the cylinder is diagnosed through excitation of a natural frequency of a misfire detection circuit coupled to the ignition coil corresponding to at least one engine cylinder.